Delaware Department of Transportation Bridge Manual

Transcription

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2 Delaware Department of Transportation Bridge Manual Shailen Bhatt Secretary of Transportation Natalie Barnhart, P.E. Chief Engineer of Transportation Joe Wright, P.E. Director of Maintenance and Operations Transportation Barry Benton, P.E. Assistant Director of Bridge Design Editor: Compiling Help: Shahin Taavoni, Ph.D., P.E. Jonathan Tice

3 DEDICATION Vasuki Hiraesave, P.E., the late District Engineer was a vital part of the fabric of Central District, DelDOT, and as such the editor felt it only appropriate to honor this man with the dedication of this manual. Our lives were made better with his presence, and we will always miss his spirit and kindness. Lead me from falsehood to truth, from darkness to light, from death to immortality. Vasuki Hiraesave Central District Engineer

4 Chapter A: Bridge Anatomy Section A.1: Bridge Types A.1.1 General... A.1.2 Beam-type Bridges... A.1.3 Arch Bridges... A.1.4 Cable-Supported Bridges... A.1.5 Truss Bridges... A.1.6 Culverts... Section A.2: Bridge Components A.2.1 General... A.2.2 Superstructure Elements... A Deck Elements... A Wearing Course... A Structural Deck... A Sidewalks... A Curbs... A Railings... A Main Load Carrying Elements... A Rolled Beams... A Plate (built up) Girders... A Reinforced Concrete Beams... A Prestressed Concrete Beams... A Trusses... A Culvert Elements... A Miscellaneous Elements... A Expansion Joints... A Open Joints... A Butt Joints... A Sliding Plate Joints... A Finger Joints... A Closed Joints... A Filled Butt Joints... A Neoprene Compression Seals... A Membrane Seal... A Cushion Seal Joint... A Modular Dam Joint... A Scuppers... A Downspouts... A.2.3 Substructure Elements... A Bearings...

5 A Abutments... A Piers... A Piles... Chapter B: Preventive Maintenance Section B.1: General B.1.1 Definition... B.1.2 Classifications of Preventive Maintenance... Section B.2: Scheduled Preventive Maintenance B.2.1 General... B.2.2 Scheduling... B.2.3 Requirements... B.2.4 Deck Cleaning... B.2.5 Bridge Drainage Systems... B.2.6 Bearings and Bearing Seats... B.2.7 Steel Horizontal Surfaces... Section B.3: Response Preventive Maintenance B.3.1 General... B.3.2 Resealing Expansion Joints... B Bridge Joint Sealing Hot Pour... B B Bridge Joint Sealing Silicone... Bridge Joint Sealing Preformed Elastomeric Compression Joint Seal... B.3.3 Protective Coatings... B Concrete Deck Sealing... B Linseed Oil Treatment to Entire Deck... B Sealing Concrete Substructures... B.3.4 Painting Structural Steel... B.3.5 Removing Debris from Waterway Channels... B.3.6 Extending or Enlarging Deck Drains... B Welded Drain Extension... B Bolted Drain Extension Using Straps... B Bolted Drain Extension Using Anchorages... B.3.7 Repairing Damage from a Vehicle Hitting the Structure... B.3.8 Lubricate Bearings... B.3.9 Suggested Rainy Day Bridge Activities...

6 Chapter C: Bridge Repairs and Rehabilitation Section C.1: Superstructure Related Work C.1.1 Deck Elements... C Deck Repair... C Deck Sealing for details see Chapter B... C Partial Depth Repair of Concrete... C Full depth repair of unsound concrete... C Total Replacement Of Concrete or Precast Deck... C Scale repair... C Spall Repair... C Polymer Deck Patching... C Asphaltic Concrete Patching... C Emergency Temporary Patching... C Precast Concrete Deck Replacement... C Timber Deck... C Open Steel Grid... C Concrete Sidewalk Repair... C Concrete Curb/Parapet Repair... C Railing/Parapet Repair... C General... C Concrete Railings... C Steel Pipe and Tubular Railings... C Aluminum Railings... C Railing Replacement With W-Beam... C Bridge Parapet Repair... C Structure Mounted Railing Repair... C Steel Guiderail Mounted to Concrete... C Steel Guiderail Mounted to Steel Beam... C Pedestrian Railing Repair... C Median Barrier Repair... C Chain Link Fence On Concrete Rail... Section C.1.2: Main Load Carrying Elements C Repairing Load carrying Steel Members... C Temporary Concrete Slab Support During Beam Replacement... C Repair of Shallow Nicks and Gouges in Steel Members... C Repair of Structural Cracks in Steel Members... C Repair of Damaged Flange/Web of Steel Beams... C Repair of Overloaded Steel Beams... C Repair of Damaged Steel Beam at Bearing Locations...

7 C Repair of Bent Steel Beams (Heat Straightening)... C Straightening Deformed Webs of Steel Beams... C Replace Steel Stringer... C Noncomposite beams... C Composite beams... C Repair/Replace Steel Floorbeam... C Repair of Steel Girders... C Repair Steel Diaphragm/Lateral Bracing... C Repairing Load Bearing Concrete Members... C Introduction... C Repair of Spalled Areas of Concrete Beams and Stringers... C Conventional repair... C Conventional reinforcement... C Prestressing steel... C Repair Prestressed Stringer (Post-Tensioning)... C Repair or Replacement of Reinforced or Prestressed C Concrete Diaphragm... Repair of Reinforced or Prestressed Concrete Members Other Than Stringers or Diaphragms... C Truss Repair... C Introduction... C Replacement of a Vertical Tension Member... C Repairing of a Diagonal Tension Members... C Replacing Vertical Compression Members... C Straightening a Steel Truss Member... C Repair of Damaged Lower Chord Members... C Tighten or Shorten Eye-bar and Rod Truss Tension Members Using Flame Shortening... C Strengthening Bottom Chord by Post-Tensioning... C Strengthening Top Chord Member... C Repair of a Floor Beam... C Strengthen Entire Bridge Cable Sling System... C Strengthen Entire Bridge Cable-Stayed Additional Support System... C Strengthen Entire Bridge Shifting Supports... C Strengthen Entire Bridge Addition of Support... C Strengthen Entire Bridge Method of Subdivision... C Strengthen Truss Connections and Braces... C End Vertical... C Eyebar at Pin-Alternate 1... C Eyebar at Pin-Alternate 2... C Pin Plate... C Lateral Connection... C Lower Lateral... C Vertical Channel at Kneebrace Connection... C Increasing Vertical Clearance by Modifying the Portal Bracing... C Repair of Timber Members...

8 C Introduction... C Temporary Repair of a Deteriorated Timber Beam... C Repair of a Split Stinger... C Repair of Decayed Stinger Ends... C Repair/Replace Timber Stringer From Under the C Deck... Repair/Replace Timber Stringer From Above the Deck... C Repair of Timber Connections... C Bolts, drift pins, and screws... C Wood scabbing... C Steel connector plates... C Nails, spikes, and screws deck connectors... C Deck Connectors... Section C.1.3: Miscellaneous Deck Elements C Expansion Joints... C Introduction... C Open Joints... C Neoprene Joints (Preformed Compression Seals)... C Cork Filled Joints... C Sliding Plate Joints... C Finger Plate Joints... C Waterproof Expansion Joints... C Neoprene Seals... C Flex Type... C Strip Seals... C Foam Type Sealants... C Evazote... C Other Joint Problems... C Drainage... C Replace Scupper Grate... C Install Drain/Scupper... C Install PVC Deck Drain... C Install Metal Drains Through Parapets... C Install Deck Drain using Eccentric Reducers... C Install Standard Scupper... C Repair/Replace Downspouting... Section C.2: Substructure Related Work C.2.1 Bearings... C Maintenance... C Sliding Plate Bearing Maintenance...

9 C Roller Bearing Maintenance... C Rocker Bearing Maintenance... C Pin-and-Hanger Bearing Maintenance... C Elastomeric Bearing Maintenance... C Pot Bearing Maintenance... C Bearing Repair... C Roller Bearing Repairs... C Rocker Bearing Repair for Reducing Expansion... C Reset Rocker Bearings... C Repair/Rehab other Steel Bearings... C Elevating Bearings to Increase Vertical Clearance... C.2.2 Bridge Seats... C Introduction... C Reconstruction of a Bridge Cap... C Bridge Seat Repair by Concrete Cap Extension... C Pedestal/Seat Reconstruct... C Pedestal/Seat Modification to Elevate Bridge Profile... Sub Section C.2.3 Abutments/Wings/Piers C Repair Substructure Cracks... C Repair Water Line Deterioration... C Repair Surface Deterioration of Abutments... C Repairing All or Portions of Concrete or Masonry Abutments... C Repairing Abutment Faces by using Jacket Concrete... C Abutment Stabilization... C Repair to Increase the Load Carrying Capacity of Deteriorated Abutment Walls or Bridge Seats... C Repair to Protect Exposed Abutment Footing and/or Piling... C Repair of Partially Spalled and Cracked Concrete C Abutment and Footings... Install L-Shaped Abutment Jacket to Strengthen Stone Abutments... C Repoint Masonry Walls... C Repair Backwall... C Replace Concrete Wingwalls... C Repair Broken or Deteriorated Concrete Wingwalls... C C Repair of Concrete Wingwall That is Breaking and Tipping Outward on One Side of Abutment... Repair of Concrete Wingwalls That Are Breaking and Tipping Outward on Both Sides of Abutment...

10 C Extend Wingwalls with Gabions... C Repair to Stabilize Existing Wingwalls with Gabions... C Repair to Protect Exposed Abutment Footing and/or Piling... C Repairing Spread Footing... C Underpin Footing with Concrete or Pumped Grout... C Underpin Footing Using Tremie Concrete... C Repair Abutment Slopewall... C Construct New Abutment Slopewall... C Piles, Piers and Bent Repair... C Repair Deteriorated Concrete Pile... C Pile Replacement... C Casting Subfooting to Cap Piles... C Repairing Concrete or Masonry Piers... C Repair of Tilted Pier and Deck... C Repair of Cracked Hammer Head Piers Using Epoxy C Grout and Reinforcement... Repair Cracked Hammer Head Piers by Post Tensioning... C Repair of Steel Piles Using Channel Splice... C Repair Steel H-Pile Bents With Concrete Jacket... C Strengthen Existing Cap... C Replacing Timber Caps... C Repairing Rotated Caps... C Repair All or Nearly All Piles in a Timber Bent... C Replacing Timber Pile Bent With Steel Columns... C Replace Single Pile... C Strengthening by Installing Helper Timber Bents... C Replace Pile Section... C Replace Timber Cross-Bracing... C Underwater Repair of Substructures... C Engineering the Repair... C Control of Work in Waterways... C Protecting Underwater Bridge Elements... C Pressure Injection of Underwater Cracks... C Concrete Repair Underwater... C Concrete Removal... C Forms... C The Mix... C Underwater Placement... C Bagged Concrete... C Prepackaged Aggregate Concrete... C Tremie Concrete... C Pumped Concrete... C Free-Dump Concrete... C Hand-Placed Concrete... Section C.3 Other Bridge Related Work

11 C.3.1 Culverts... C Repair Headwall/Wings... C Replace Headwall/Wings... C Repair or Replace Culvert Apron/Cutoff Wall... C Repair Culvert Barrel... C.3.2 Erosion Control... C Repair or Construct Streambed Paving... C Paving Metal Bottom Pipes, Arches and Culverts... C Dumped Riprap (Rock Protection)... C Gabion Baskets (Rock Protection)... C Repair or Construct Stream Deflector... C Excavate and Fill Scour Hole... C Repair of Scour Holes Beneath Concrete Footings... C Removal of Vegetation/Debris... C Removal Depositation... C.3.3 Construct Temporary... C Construct Temporary Support Bent... C Construct Temporary Pipes... C Construct Temporary Bridge... References Appendix 1 Appendix 2 Appendix 3

12 Chapter A Bridge Anatomy - 1 -

13 A. Bridge Anatomy A.1. Bridge Types A.1.1. General. Bridges incorporate four basic types of structural systems to provide capacity to carry the various loads and forces resulting from those loads, namely: Beam-type Bridges Arch Bridges Cable Supported Bridges Truss Bridges Culverts A.1.2. Beam-type Bridges. The most common example of this type of bridge construction is a structure of rolled steel beams with shear studs attached to the upper flange and a reinforced-concrete deck placed on top of the beams that then acts as an integral structural unit when the studs transmit forces from the deck to the beams. (1) Figure A. 1 Figure A

14 Figure A. 3 Figure A. 4 Figure A. 5 Figure A

15 A.1.3. Arch Bridges. Structural arches have been incorporated into bridge design to permit the loads on the bridge to be carried entirely by compression against the bridge abutment. In early bridgebuilding technology, arch bridges were required to permit the construction of bridges with masonry materials and other materials that could not carry tension or be fastened to carry tension. Modern arch bridges may be designed to be constructed from steel or reinforced-concrete members that are so delicate in their dimensions that the tension forces they are capable of resisting are negligible in comparison to the compression forces they resist. (1) Figure A. 7 Figure A. 8 Figure A. 9 Figure A

16 A.1.4. Cable-Supported Bridges. Cable-supported bridges are usually classified as either cable suspension bridges or cable-stayed bridges. Typically, suspension bridges have two tall towers near the ends of the cable-supported span from which the cables on each side of the suspended roadway are hung. In contrast, a typical cable-stayed bridge may have one or more tall towers from which cables run to the adjacent suspended roadway in a radiating pattern of individual cables. Cable-supported bridges are often used to cross long spans where high clearances above the water are needed. (1) Figure A. 11 Figure A

17 A.1.5. Truss Bridges. A truss is a system of structural members joined at their ends to form a stable framework. A bridge may be designed such that the truss acts as a beam with the same function as reinforced-concrete beams or structural steel beams, or an arch may be created from a series of curved trusses. The unique characteristic of trusses is that all loads are transformed into axial (either tension or compression) loads in the individual members of a truss, even though the truss itself may be resisting shear and moment loads. (1) Figure A. 13 Figure A

18 Figure A. 15 Figure A

19 A.1.6. Culverts There are several different types of culverts, the most common being: Corrugated Metal Galvanized Steel Plate Culvert Four-sided Precast Concrete Box Culvert Corrugated Aluminum Box Culvert Three-sided Precast Concrete Box (Framed) Culvert The most common is the box culvert, which is usually a closed, rectangular frame. Box culverts range in size from small, single-cell units to multicell units as large as 20 by 20 feet. Natural rock may also be used as a floor instead of being closed. Usually, transverse joints are provided every 20 to 30 feet. Some of these slabs are made of stone, while some walls are made of rubber masonry, rather than concrete. (4) Figure A. 17 Four-sided Precast Concrete Box Culvert Figure A. 18 Corrugated Aluminum Box Culvert - 8 -

20 Figure A. 19 Three-sided Precast Concrete Box (Framed) Culvert - 9 -

21 A.2. Bridge Components A.2.1. General. A bridge is made up of two major components: The Superstructure The Substructure The superstructure includes all those parts which are supported by the substructure, with the main part being the bridge spans. Vehicular forces are transmitted from the bridge deck, through the supporting beams or girders of the span, and into the substructure. (4) The substructure includes those parts which transfer the loads from the bridge span down to the supporting ground. (4) A.2.2. Superstructure Elements. Some different types of superstructures: Figure A. 20 Masonry Arch Figure A. 22 Truss Figure A. 21 Through and Deck Girder Figure A

22 The superstructure can be divided into three major element groups: Deck Elements Main Load Carrying Elements Miscellaneous Elements A Deck Elements The deck is the portion of a bridge which provides direct support for vehicular and pedestrian traffic. The deck may be a reinforced concrete slab, timber flooring, or a steel plate or grating on the top surface of abutting concrete members or units. (4) A typical deck may be made up of the following: A Wearing Course The Structural Deck Sidewalks Curbs Railings, etc. A Wearing Course (Tread) The wearing course provides the riding surface for traffic and is placed on top of the structural slab. There are also wearing courses poured integral with the structural slab. When this technique is used it is generally referred to as a monolithic deck. Wearing courses can be either asphalt concrete or portland cement and are not considered to provide load carrying capacity. (2) A Structural Deck The structural deck or slab provides the load carrying capacity of the deck system. (2) It s primary purpose is to provide a roadway for moving vehicles and to distribute their loads, but from a maintenance perspective it also provides a cover for primary members, bearings and substructures, protecting them by diverting debris, salt, and moisture. (3) Typical structural deck systems are: Reinforced Concrete with separate wearing surface Reinforced Concrete with integral wearing surface Prestressed concrete box beams Precast concrete planks Steel Plates (Orthotropic decks) with thin wearing course overlay Open Steel Grid Concrete Filled Grid Timber Planks (nail-laminated, glue-laminated, stress-laminated Asphalt-filled metal stay-in-place (SIP) forms (2) (3) A SideWalks Sidewalks are provided on structures where pedestrian traffic counts warrant their use. Otherwise, safety walks are generally recommended. (2) Typical sidewalks are: Reinforced concrete Steel plate

23 Wood planking Filled grid (2) A Curbs Curbs are provided in conjunction with sidewalks and safety walks. Curbs can be constructed of reinforced concrete, pre-cut granite, timber or steel plate. (2) A Railings Railings are placed along the extreme edges of the Deck system and provide protection for traffic and pedestrians. There are a wide variety of railing materials and configurations. (2) Some of the more common are: Metal multiple rail systems Box Beam W-Beam Reinforced concrete Timber (2) A Main Load Carrying Elements These elements support the dead load and live loads transmitted through the deck. Because they transfer live and dead loads to the substructure, section losses resulting from corrosion may decrease their load-carrying capacity. Some common load carrying members are: (3) Rolled beams Plate (built up) girders Reinforced concrete beams Prestressed concrete beams Trusses. A Rolled Beams The rolled beam is used for short spans. The beam comes from the rolling mill as an integral unit composed of two flanges and a web. The flanges resist the bending movement and the web resists shear. (2) The more common types of rolled beam shapes are: a) Figure A. 24 Standard Beam c) Figure A. 26 Channel Section b) Figure A. 25 Wide Flange

24 Figure A. 27 A Plate (built up) Girders This type of structural member is used for intermediate span lengths not requiring a truss and yet requiring a member larger than a rolled beam. The basic elements of a plate girder are a web to which flanges are riveted or welded at the top and bottom edges. (2) The most common forms of cross section are shown below: a) Figure A. 28 b) Figure A. 29 Riveted with Cover Plate The portion above the neutral axis of the plate girder will be in compression and the portion below the neutral axis will be in tension for simple span structures. FLANGE ANGLES Flange angles are used for riveted plate girders and carry tensile or compressive forces induced by bending. COVER PLATES Cover plates are welded or riveted to the top and/or bottom flanges of the girder to increase the load carrying capacity. BEARING STIFFENERS These are either plates or angles placed vertically at the location of the support and attached to the web. Their primary function is to transmit the shearing stresses in the web plate to the bearing device, and by so doing prevent web crippling and buckling. INTERMEDIATE STIFFENERS Intermediate stiffeners are used at points of concentrated loads or for deep girders to prevent web crippling and buckling. (2)

25 Figure A. 30 A Reinforced Concrete Beams The concrete beams are reinforced wherein the tensile stresses (whether resulting from bending, shear or combinations thereof produced by transverse loadings) are by design carried by the steel reinforcement. The concrete takes compression and shear only. It is commonly rectangular or T-shaped with its depth dimension greater than its stem width. (2) A Prestressed Concrete Beams The two main types of prestressed concrete beams are box beams and I-beams. The box beams are constructed with a rectangular cross section with a single void inside. The top and bottom slabs of the box act as the flanges while the sidewalls act as webs. The most common prestressed concrete I-beams are the AASHTO shapes. The cracking and tensile forces in the prestressed concrete are greatly reduced by compressing it with tensions cables or bars. (2) A Trusses The truss is one form of structural system which, because of its characteristics, can be used to span greater lengths than rolled beams and girders. The truss functions basically in the same manner as a rolled beam or girder in resisting loads the top and bottom chords act as the flanges of the beam and the diagonal members act as the web. (2) CHORD In a truss, the upper and lower longitudinal members extending the full length are termed chords. The upper portion is designated the upper or top chord and correspondingly the lower portion is designated the lower or bottom chord. For a simple span, the top chord will always be in compression and the bottom chord will always be in tension and should be considered a main structural member. Failure of either chord will render the truss unsafe. DIAGONALS The diagonal web members span between successive top and bottom chords and will either resist tension or compression depending on the truss configuration and the live load position. Most diagonals are also main structural members and their failure would be extremely critical and render the truss unsafe. VERTICALS Vertical web members between top and bottom chords which will resist either tension or compression stresses depending on the truss

26 configuration. Most verticals are also main structural members and their failure would usually be critical and render the truss unsafe. PANEL POINT The point of intersection of primary web and chord members of a truss. The items below can be considered secondary structural members and although their failure should receive immediate attention an individual member failure will not render the structure unsafe. PORTAL BRACING The portal bracing is found overhead at the ends of a thru truss and provides lateral stability and shear transfer between trusses. SWAY BRACING Sway braces are secondary structural members spanning between the trusses at interior panel points and provide lateral stability and shear transfer between trusses. TOP LATERAL BRACING The top lateral braces lie in the plane of the top chord and provide lateral stability between the two trusses and resistance to wind stress. BOTTOM LATERAL BRACING The bottom lateral braces lie in the plane of the bottom chord and provide lateral stability and resistance to wind stresses. FLOOR BEAM The floor beam spans between trusses at the panel points and carry loads from the floor stringers and deck system to the trusses. STRINGERS The stringers span between floor beams and provide the primary support for the deck system. The deck loading is transmitted to the stringers and through the stringers to the floor beams and to the truss. GUSSET PLATES These plates connect the structural members of a truss, on older trusses, pins are used instead of gussets. Figure A

27 A Culvert Elements Generally, every part of a culvert (top, walls and floor) can be considered to be load-carrying since culverts are made of a whole-piece section and live loads are transmitted through the whole of the culvert and onto the ground or footer. A Miscellaneous Elements Elements classified here as miscellaneous are: Deck Expansion Joints Suppers Downspouts A Expansion Joints Bridge deck expansion joints accommodate movement of the superstructure as live loads move across the bridge, as environmental conditions change, and as the bridge materials themselves change over time. Live-load deflection and substructure settlement can cause rotational movement. Skewed bridges can develop significant maintenance problems because of the difficulty of allowing transverse movement through the joints. Movement is usually allowed by providing a space between rigid sections of the superstructure equal to or greater than the movement expected. This space requires a break in the deck surface that adversely affects ride quality and provides an opportunity for water and other contaminating materials to reach the structural elements below the deck. (1) The two general types are: Open joints Closed joints: A Open Joints: In open joints, water and contaminating materials are allowed to pass through the joint and onto elements beneath or are collected in a drainage trough to move them away from sensitive areas of the bridge structure. This type of joint is not used as much now as in the past because the drainage trough must be well maintained and because it allows water and material to move directly into the deck. Some types of open joints are: (1) Butt Joints Sliding Plate Joints Finger Joints A Butt Joints: Butt joints may or may not be reinforced at the joint face. They are often used where the movement is limited to 25 mm (1 inch) or less and may be commonly found in a bridge at a point where only rotation movement is expected with some minor thermal expansion or contraction. It is difficult to protect the joint from corrosion. If the deck receives an asphalt overlay and the joint has a reinforced face, then the reinforced face should be extended through the overlay. Normal maintenance includes periodically clearing the opening of roadway debris, painting, and repairing the roadway surface adjacent to the reinforcement (armor plate). (1)

28 Figure A. 32 A Sliding Plate Joints: Sliding plate (plate dam) joints are typically used when movement between 25 mm (1 inch) and 75 mm (3 inches) is expected. This was the predominant type of bridge expansion joint used before neoprene joints were developed. Plate joints tend to be difficult to maintain. The plates clatter and bang when hit by a vehicle; they sometimes come loose from the bridge, presenting a roadway safety problem. Maintenance personnel need to clean the joint periodically to prevent excessive buildup of debris in the joint, to check for deterioration of the concrete in the vicinity of the joint, to check for deterioration of the anchor bolts holding the plate in place, and to keep all exposed metal parts painted and free of corrosion. (1) Figure A. 33 Expansion Joint (Sliding Plate Type) A Finger Joints: When movement is expected to be more than 75 mm (3 inches), a finger or cantilever joint is typically used. These joints require the same type of maintenance care as sliding plate joints, in addition to maintenance of the drainage trough typically installed under the finger joint. (1) Figure A. 34 Finger Joint with Drainage Trough

29 A Closed Joints: Closed joints are designed and intended to be waterproof. Some types of closed joints are: Filled Butt Joint Neoprene Compression Seal Joint Membrane Seal Joint Cushion Seal Joint Modular Dam Joint. (1) A Filled Butt Joints: This joint is very similar to an open butt joint and is intended to be applied to the same general movement conditions, except that a premolded joint material is usually attached to one face of the joint or supported from beneath by an offset in the vertical slab of the deck. Sealant material is placed into the joint at the roadway surface, sealing the opening and preventing water from entering the joint. Maintenance typically includes periodic cleaning of the point, replacing the sealant at the roadway surface, replacing the filler material when needed, and repairing the roadway surface adjacent to the joint when needed. Generally, a poured-in-place seal performs best when the expected movement is less than about 13 mm (about 0.5 inch). (1) Figure A. 35 Filled Joint A Neoprene Compression Seals: These seals can be used where deck movement up to about 65 mm (about 2.5 inches) is expected. Successful joint operation requires that the initial installation provide a properly sized opening so that under low temperatures tensile stresses will not separate the seal from the deck face and under high temperatures compressive stresses will not crush or damage the seal. Maintenance includes sweeping or flushing the deck to prevent incompressible fine materials from building up in the joint area and periodically inspecting the seal for cracking and deterioration from weathering effects. (1)

30 Figure A. 36 Compression Seal Figure A. 37 Compression Seal with Overlay A Membrane Seal: A membrane (strip) seal is a flexible sheet of neoprene rigidly attached to two metal facings at the joint. The installed seal has a downward curved shape and flexes ( stretches ) with the bridge deck s movement. Membrane seals can be applied where movement up to about 100 mm (about 4 inches) is expected. Installations sometimes leave breaks or cracks in the seal at gutter lines and at points where a change in the deck cross section occurs. Debris and fine material in the joint space can tear the seal or cause it to come out of the metal facing under the downward force of vehicle wheels. Maintenance, therefore, should include periodically removing debris and reattaching or replacing defective membranes. Figure A. 38 Membrane (Strip) Seal A Cushion Seal Joint: In a cushion seal (elastomeric) joint, a reinforced neoprene pad is rigidly attached to each side of the joint. The neoprene pad has elastic characteristics that allow it to stretch when the joint opens and shrink when the joint closes, while the reinforcing materials in the pad provide sufficient strength to span the joint gap in a durable manner. Cushion seal joints are normally used to span joints with movement up to about 100 mm (about 4 inches). These joints need regular inspection to ensure that the cushion remains firmly anchored, especially when the bridge contracts. Joint maintenance at a curb line can require frequent attention also. A cap to seal the anchor area can be glued down with adhesive and aid in maintaining a watertight seal, but frequent inspection is needed because the adhesives tend to deteriorate, resulting in cap loss and leaking joint seals. These joints should be periodically cleaned, the anchoring devices should be inspected and replaced when needed, and the seal repaired when needed

31 Figure A. 39 Cushion Joint A Modular Dam Joint: These joints are typically fabricated to accommodate joint movements in excess of about 100 mm (about 4 inches). These joint seals are special designs incorporating strip or compression seals separated by beams and supported by a series of bars. They are designed to allow some individual sections and components to be replaced as needed. These joint seals should be inspected periodically, especially after snowplowing season in snow and ice climates because snowplow blades can damage them. Impact from heavy traffic is also a source of damage, necessitating regular inspections. Like strip seals, these joints need to be periodically cleaned for the same reasons. Figure A. 40 Upgrading Joint to Accommodate Compression Seal A Scuppers These are located along the curb line and provide drainage from the deck. (2)

32 A Downspouts When it is not desirable to allow water from the scuppers to fall free, it is carried off by pipes (downspouts). (2) Figure A. 41 PVC Deck Drain A.2.3. Substructure Elements. The main elements found in the substructure are: Bearings Abutments Piers Piles A Bearings Bearings transmit the superstructure load to the substructure. They are also provided for longitudinal movement due to expansion and contraction and rotational movement due to deflection. (2) Figure A. 42 Some typical Bearings

33 A Abutments Abutments are substructures supporting the end of a single-span or the extreme end of a multispan superstructure and usually retaining or supporting the approach embankment. Typical abutments are shown in Figure A. 43. Abutments usually consist of a footing, a stern or breast wall, a bridge seat, a backwall, and wing walls. The backwall prevents the approach embankment soil from spilling onto the bridge seat, where bearings for the superstructure are situated. The wing walls are retainers which keep the embankment soil around the abutment from spilling into the waterway or roadway that is spanned by the bridge. When U-shaped wing walls are used, parapets and railings are often placed on top of them. Abutments may be constructed of plain concrete, reinforced concrete, stone masonry, or a combination of concrete and stone masonry. Plain concrete and stone masonry abutments are usually gravity structures, while reinforced concrete abutments are mostly cantilever or counterfort types. (4) Figure A. 43 Abutment Types and Components A Piers - Bridge Piers transmit the load of the superstructure to the foundation materials and provide intermediate supports between abutments. (2) Here are six typical piers: Frame piers Dumbbell Piers Hammerhead piers Column Piers Solid-stem piers Pile-bent piers (3)

34 Figure A. 44 Pier Types A Piles Piles are used to transmit the bridge loads to the foundation material when soil conditions are not suitable for receiving the load in bearing. (2) Typical pile types are: Steel H Piles Timber Concrete piles (both CIP and precast) Concrete filled pipe or shell piles (2) Figure A. 45 Pile Bent and Frame Bent Pier

35 Chapter B Preventive Maintenancee

36 B. Preventive Maintenance B.1. General B.1.1. Definition Preventive maintenance can be defined as the act of keeping a structure in its as-built condition and/or protecting it from inevitable deterioration due to environment, traffic vibration and deicing chemicals. In some cases, structures are built with flaws such as cracks in concrete which require action to prevent moisture and chlorides from infiltrating the micro-structure and causing early deterioration. One fact remains, however; a structure starts to deteriorate the day its construction is completed, and it is the duty of the person in charge to slow the deterioration as much as practical using methods and materials that are considered best practices. It is always more cost-effective in the long run to perform preventive maintenance activities than to allow a known condition get progressively worse until the entire member or structure has to be replaced. Many times on a bridge, there are numerous visual defects which may be overwhelming as to what should be fixed now and what can be deferred. Usually a bridge deteriorates from the top (deck) down. (5) B.1.2. Classifications of Preventive Maintenance Preventive maintenance activities can be classified into two groups: scheduled and response. (a) Scheduled preventive maintenance is the systematic servicing of bridges on a scheduled basis. The interval varies according to the type of work or activity. Tasks identified as interval maintenance can be incorporated into a maintenance schedule for that bridge. (4) (b) Response preventive maintenance is the activities that are performed when the need is foreseen for remedial work to prevent further deterioration or the development of defects. The need for this type of maintenance is often related to the environment or identified during inspections. (4)

37 B.2. Scheduled Preventive Maintenance B.2.1. General Typical activities that are conducted on a scheduled interval basis include: Cleaning decks; Cleaning bridge drainage systems; Cleaning bearings and bearing seats; Cleaning Steel Horizontal Surfaces. B.2.2. Scheduling The maintenance activities described in this section should generally be preformed annually, after the winter season is over, or as needed. B.2.3. Requirements Equipment Sweeper Water Tank with pressure hoses or compressor Front End Loader Snakes or Roto-rooter Wire Brush Access Equipment Materials Water Lubricate Paint Labor 1 Foreman 2 Crew Members 1 Special Crew Member (Operator) B.2.4. Deck Cleaning Proper maintenance of bridge decks is very critical, not only from a structural integrity preservation viewpoint but also from one of public perception. Decks littered with antiskid materials contribute to the chloride contamination of concrete and corrosion of reinforcing steel which, in turn, accelerates the formation of potholes and the ultimate deterioration of highway structures. Decks normally consume a large part of the maintenance dollar, and all efforts to reduce these sometimes unnecessary expenditures should be encouraged as much as possible by managers at all levels. A quality deck preventive maintenance program will go a long way in minimizing repair costs. Winter snow and ice removal activities deposit antiskid materials and chemicals on bridge decks which normally tend to accumulate over the winter within the area of the water table near scuppers and around structural members (panel points of trusses, flange angles, and bottom flanges of plate girders). As soon as practical (when the threat of snow has subsided to a reasonable level) this debris should be removed by sweeping and/or flushing

38 Care should be exercised when cleaning decks to prevent debris from entering the drainage system (scuppers and downspouts) which could create serious problems. Structural members of the superstructure such as end posts, diagonals and vertical web members, panel points of trusses and flange angles, stiffness, web plates and bottom flanges of plate girders that lie within the wheel splash zone should also be cleaned of debris and salt residue by pressurized flushing, air blasting, scraping, brushing or mechanical devices. Areas that exhibit signs of corrosion should be noted, reported to the Bridge Engineer and scheduled for painting or repair. (2) In open joints, water and contaminating materials are allowed to pass through the joint and onto elements beneath or are collected in a drainage trough to move them away from sensitive areas of the bridge structure. The drainage trough must be well maintained because it allows water and material to move directly into the deck. Clean the joint periodically to prevent excessive buildup of debris in the joint, to check for deterioration of the concrete in the vicinity of the joint, to check for deterioration of the anchor bolts holding the plate in place, and to keep all exposed metal parts painted and free of corrosion. Procedures 1. Sweep loose material from parapets, railings, and sidewalks onto bridge deck by manual or mechanical means. Utilize mechanical removal devices (i.e., street sweepers) in areas where the equipment is available. 2. Sweep and collect material from the deck. Do not deposit material in drainage facilities or joints. Minimize discharge of loose material, grit and debris into the water. 3. Remove remaining dirt and debris from deck joints and drains. 4. Dispose of collected cleanings at a proper disposal or fill site. 5. Use clean water when flushing the deck. Water should be obtained from the same water body that the bridge being cleaned spans. For small streams, where a significant decrease in stream flow is likely, water may be brought to the site providing it is of equal or better quality than the background stream quality. 6. Minimize the amount of debris entering the water body. For instance, where feasible, cover or plug scuppers to prevent debris and cleaning water from entering the stream. 7. When cleaning open grid decks flush supporting structural members also. 8. Use temporary silt fencing and other erosion control measures where necessary to prevent stream bank sediments from entering the stream. (8) B.2.5. Bridge Drainage Systems The operation and maintenance of bridge drainage systems is a very important element of bridge preventive maintenance. Deck drainage is required for proper maintenance of bridges since the lack of proper drainage affects many elements of the structure. Poor drainage is normally due to the accumulation of antiskid material and other debris within the drainage system preventing proper operation. Backed up water might then freeze and rupture the pipe, and may contain corrosive chemicals which, when leaked through the rupture, will attack structural elements of the bridge. Bridge drainage systems consist of: scuppers drop through and piped, gratings (open steel grid floors), open joints with troughs and all associated piping. (2)

39 All scuppers should be examined frequently for proper operation and cleaned when necessary. Antiskid or other debris should be removed by water pressure or metal probes. Particular attention should be applied when flushing antiskid from decks to prevent it from entering the drainage systems and compounding the problem. (2) Troughs under open joints are susceptible to debris accumulation with subsequent backup of drainage which contributes to the accelerated deterioration of concrete, corrosion of steel and erosion of earth. These troughs should also be inspected at frequent intervals and cleaned as required. (2) Procedures 1. Remove debris from grating and lift grating from scupper. 2. Remove debris and sediment from scupper box and pipe. 3. Flush pipe and downspouting with water. Do not use high-pressure water that may damage joints or anchors. Minimize discharge of loose material, grit and debris into the waters of the Commonwealth. 4. If debris has accumulated in downspouting, remove cleanout plugs as necessary and dislodge with water, snakes, or "roto-rooter" type devices. 5. Replace grating and cleanout plugs. 6. Dispose of collected cleanings at a proper disposal or fill site. 7. Use clean water when flushing scuppers and downspouts. Water should be obtained from the same water body that the bridge being cleaned spans. For small streams, where a significant decrease in stream flow is likely, water may be brought to the site providing it is of equal or better quality than the background stream quality. 8. Minimize the amount of debris entering the water body. (8) B.2.6. Bearings and Bearing Seats This element is the top of the piers, bents and abutments upon which rests the bearings. Any deterioration of this section could result in differential settlement of the superstructure and unplanned stresses. The most common problem is the general deterioration of the concrete. This can be the result of chemical attack, poor aggregates, poor concrete, freeze/thaw damage, insufficient reinforcing steel coverage or various combinations of these. The damage is usually in the form of scaling, popouts or sloughingoff at the corners. Due to the proximity of leaking joints which tends to deposit chemical-laden dirt and debris in this area, the depth of deterioration is likely to be greater at this location than at other locations. The most important step in preventing damage to the caps and seats is to reduce the amount of leakage from the joints. Runoff from scuppers and joints should be diverted by pipes or splash plates. The chemical-laden dirt and debris should not be allowed to accumulate on these surfaces. These surfaces should be flushed annually after the threat of snow and ice has diminished or passed. In the event the caps and seats are steel, the most common problem is rust and the resultant corrosion. The same preventive maintenance procedures outlined for concrete should be followed for steel and, in addition, proper painting schedules should be developed to prevent corrosion problems. (2) All rockers, pins, and rollers are to be kept free of debris and corrosion, lubricated where necessary, and maintained in good working order. Depending on the type of bearing (fixed or expansion), they should permit the superstructure to undergo necessary

40 movements without developing harmful overstresses. A frozen or locked bearing that becomes incapable of movement allows the stresses generated to become excessive and may even cause a major failure in some affected member. (4) Beam ends, which would include the last one or two feet of the beam and the back side of the bearing at expansion joints, are most vulnerable to determine due to leaky joints. Beam ends should be flushed along with the cleaning of bearings and beam seats. (2) Procedures 1. Set up scaffolding or ladders, or position manlift or snooper truck as required. 2. Manually dry clean the bearing and bearing seats, by scraping, brushing or chipping all accumulated debris. Material should be collected and disposed of at a proper disposal or fill site. 3. Remove loose paint by dry brushing. Collect and dispose of at an approved disposal site. Avoid paint chips from entering water bodies. 4. Thoroughly flush all bearings and bearing seats at piers and abutments with pressurized water to remove salt, dirt and debris, that could not be removed by manual cleaning methods. 5. Limit wet cleaning to (5) feet on either side of the joint at the pier, unless debris in other areas require further cleaning. Clean (5) five feet from each abutment. 6. Use clean water when flushing the bearings and bearing seat. Water should be obtained from the same water body that the bridge being cleaned spans. For small streams, where a significant decrease in stream flow is likely, water may be brought to the site providing it is of equal or better quality than the background stream quality. 7. Minimize the amount of debris entering the water body. 8. Use temporary silt fencing and other erosion control measures where necessary to prevent stream bank sediments from entering the stream. (8) 9. Lubricate Bearings where necessary and possible without jacking the superstructure. B.2.7. Steel Horizontal Surfaces The elements most usually affected by splash are piers/columns within the "splash zone" (usually shoulder piers), and the lower portion of beam webs due to salt spray collecting on top of the bottom flange directly over passing traffic. (5) Procedures 1. Set up scaffolding or ladders or position manlift or snooper truck as required. 2. Manually dry clean the horizontal surfaces, by scraping, brushing or by other hand or mechanical means all accumulated debris. Material should be collected and disposed of at an approved disposal site. 3. Remove loose paint by dry brushing. Collect and dispose of at an approved disposal site. Avoid paint chips from entering water bodies. 4. Thoroughly flush all horizontal surfaces of structural steel members, with pressurized water to remove salt, dirt and debris, that could not be removed by manual cleaning methods. 5. Limit wet cleaning of steel horizontal surfaces to five (5) feet on either side of the joint at the pier and five (5) feet out from the abutment, unless debris in other areas require further cleaning. Fascia beams may be flushed their entire length. 6. Use clean water when flushing steel horizontal surfaces. Water should be obtained from the same water body that the bridge being cleaned spans. For small streams,

41 where a significant decrease in stream flow is likely, water may be brought to the site providing it is of equal or better quality than the background stream quality. 7. Minimize the amount of debris entering the water body. 8. Use temporary silt fencing and other erosion control measures where necessary to prevent stream bank sediments from entering the stream. (8)

42 B.3. Response Preventive Maintenance B.3.1. General Typical activities that are performed on an as-needed basis include: 1. Resealing expansion joints; 2. Sealing concrete decks or substructure elements; 3. Painting structural steel members; 4. Removing debris from waterway channels; 5. Extending or enlarging deck drains; and 6. Repairing damage from a vehicle hitting the structure. (1) 7. Lubricating Bearings when superstructure jacking is required. B.3.2. Resealing Small Expansion Joints Some deck joints are sealed and some are not. Damaged joints or leaking seals need to be repaired or replaced for the bridge to function as the original design intended. Leaving a damaged deck joint or breaking seal unattended also increases exposure of the bridge structural elements under the deck to increased damage from debris and contaminating materials from the deck surface. No bridge deck joint is perfect, but if a bridge deck joint was properly installed at the original construction and is well maintained, it will contribute to a bridge s long, effective service life. Ideally, a joint should be watertight, allow deck movement in expansion and contraction, last at least as long as the adjacent deck materials, and never require any maintenance. However, maintenance personnel will have to deal with less than ideal joints. (1) There are three main types of material for repair of small joints these are: (a) Hot pour rubberized (b) Silicone (c) Compression type seal B Bridge Joint Sealing Hot Pour The purpose of this activity is to prevent dirt, debris, and chlorides from deteriorating the deck and supporting bridge members. Scheduling should be March thru May and September thru December, weather permitting with temperatures between 45 to 80 degrees. No significant precipitation with 24 hours. (11) Sealing of bridge approach or deck joints with hot pour material should be used at all bridge ends which butt against asphalt approach pavements or in concrete to concrete joints which are 1 ½ inches or less in width and do not exhibit significant movement. (11) Equipment Sealant Melter/Applicator Air Compresor Backer Rod Roller Materials Crafco AR Plus or approved equal Heat resistant backer rod Procedures: 1. Perform any repairs to joint, as required, before attempting to do any hot pour work

43 2. Using hand tools or other equipment as required, clean out as much of old sealant and debris as possible to depth three times the width of joint. 3. Do not apply material to joint faces that are wet or damp. If any dampness remains in the joint, dry with heat lance or compressed air. For joints greater the one half inch, install backer rod to a depth one inch below the roadway surface. For joints less than one half inch, no backer rod is required. (11) The backer rod may be installed by hand, but a roller device (See Figure B.1) to aid in placement can be easily constructed. This device will not only speed installation but also insure a consistent, uniformly placed backer at the proper depth. In cases where the pavement is faulted or where future surface grinding may be anticipated, the backer rod (and sealant) may be installed deeper than normal; however, the sealant bead thickness should not be increased. (10) Figure B.1 Backer Rod Roller 4. Clean out the area with compressed air. Apply the sealant in the joint as per manufacturers recommendation. The correct filling of a joint is shown in the figure below (Figure B.2)

44 Figure B.2 Joint Seal Installation (both hot-pour and cold-applied sealants) 5. If traffic needs to be turned onto the area before the joint sealant can appropriately set up, spray the sealant with water-soap mixture and restore traffic. (11) B Bridge Joint Sealing - Silicone The purpose of this activity is to prevent dirt, debris, and chlorides from deteriorating the deck and supporting bridge members. Scheduling should be late April thru early June and mid September thru early November, weather permitting with temperatures between 55 to 80 degrees. No significant precipitation within 36 hours prior to installation. (11) Sealing of concrete-to-concrete bridge approach or deck joints with silicone material should only be done during moderate temperatures. Use silicone products only at concrete or steel joints which are in good condition. Use silicone when one of the following conditions is present in a concrete-to-concrete joint: (11) Joints which are one inch or less in width that are very clean to work with and would require very little hand or mechanical cleaning to prepare. Use DOW 890- SL or approved equal. (11) Joints greater than one inch in width but less than 2 ½ inches wide, that are very clean to work with and would require only minimal mechanical or hand cleaning to prepare. Use DOW 902-RCS (rapid setting) or approved equal. (11) Equipment Saw Water Blaster Sandblaster Air Compressor Bazooka gun or hand caulk gun Materials

45 DOW 902-RCS, DOW 888, or 890-SL or approved equal Backer rod Primer (Note: refer to Dow Corning table for appropriate primer required.) (11) Procedures: Perform any repairs to joint, as required, before attempting to do any silicone work. It is vital that concrete faces are in sound condition or the silicone will pull off the weak concrete. Joints repaired with concrete products shall be allowed to cure for fourteen days. Joints repaired with epoxy products shall be cured in accordance with manufacturer s recommendations. For example, with Silspec 900 PNS or approved equal (See Figure B. 3): Figure B. 3 Repair of Joint for Sealing 6. Using hand tools or other equipment as required, clean out as much of the existing old sealant and debris as possible to a depth three times the width of joint. 7. Sandblast the joint faces with black beauty or other clean abrasives. 8. Inspect vertical faces to assure that they are immaculately clean and no residue is present. 9. Prime the joint faces with recommended material and allow to cure as per manufacturer s guidelines. 10. Install appropriate size backer rod to a completely snug fit but not over compressed. Installation of backer rod should be to a depth one half the joint width, plus an additional one half inch but not greater than 1 ¼ total depth below the roadway surface. 11. Install silicone with Bazooka gun for 902 or hand caulk gun for 890 to one half inch below roadway. 12. Thoroughly clean out Bazooka gun as recommended by manufacturer after completing installation. (11) B Bridge Joint Sealing Preformed Elastomeric Compression Joint Seal (Polytite or approved similar) The purpose of this activity is to prevent dirt, debris and chlorides from deteriorating the deck and supporting bridge members. Scheduling should be October thru April with temperatures between 40 to 65 degrees. Equipment Sand Blaster Materials Polytite or approved equal Epoxy adhesive

46 Sand Blasting Abrasive (Black beauty abrasive or approved equal) Procedures: 1. Perform any repairs to the joint, as required, before attempting to seal with Polytite or approved equal. Minor spalls or chipping of the concrete are acceptable. Joints repaired with concrete products shall be allowed to cure for fourteen days. Joints repaired with epoxy products shall be cured in accordance with manufacturer s recommendations. 2. Using hand tools or other equipment as required, clean out as much of the existing sealant and debris as possible to a depth of at least 5 inches. 3. Sandblast the joint faces with black beauty or other clean abrasives. 4. Mix and apply epoxy adhesive to sidewalls of joint face. 5. Release Polytite or approved equal from packaging and pull off tape to expose tacky surface. Slide material down into the gap leaving material one-quarter inch below roadway surface. Upon release from packaging, Polytite or approved equal will begin to expand so install product immediately. It may be necessary to install temporary shims against the sidewalls between the joint face and the Polytite or approved equal to help hold the material in place. Remove shims when the material has adequately expanded. 6. Coat adjacent pieces or Polytite or approved equal with silicone caulk when working across the joint opening, and push snugly to fit against each additional section. Caulk the top of the butt joint at the roadway surface. Material should be sized to fit as snugly as possible into the joint. The expansion is based on temperature and colder temperatures may take longer to expand. Acceleration of the expansion may be obtained by using artificial heating source. The material should be placed in a warmer environment such as truck cab on colder days to help the material expand quicker when the release tape is removed. B.3.3. Protective Coatings Protective coatings for reinforced concrete surfaces are available that prevent or minimize scaling or spalling. Apply to exposed concrete roadway surfaces of bridge decks, to curbs, sidewalks, divisors, concrete median barriers, inside and top surfaces of parapets and to abutments, pier caps and end walls. Some materials which can be used are boiled linseed oil petroleum spirits mixture and epoxy-resin. To be effective, these sealants should be applied before opening the roadway to traffic. (2) B Concrete Deck Sealing Sealer materials require penetration since the surface film is worn away by traffic abrasion. Sealer materials include silanes, siloxanes, silicone, epoxies, and methyl methacrylates. Good sealing requires a clean deck, a dry deck, and warm temperatures. Equipment Compressor w/hoses, etc. Truck w/pumps & spray bar Paint/herbicide spray unit Paint rollers & brushes Shovels, scrapers, & brooms Sandblaster

47 Personal safety equipment Various handtools Materials Water Blasting sand Sealer (silanes, siloxanes, silicone, polymers) Procedures 1. Clean the deck by brooming, washing, air-blasting, or a combination thereof. For some sealants, sandblasting or shot-blasting may be recommended by the manufacturer. 2. Check the environmental conditions with respect to the agency s and/or the manufacturer s specifications for sealant application. Typical items to be checked are as follows: Correct temperature of air and deck. Temperature range of materials as recommended. Wind velocity low enough to prevent air drift. No falling temperature during or immediately after application. Clean deck with no moisture or oil on it. Other conditions that could prevent satisfactory application. 3. Mark off or measure areas to be sealed, ensuring the correct rate of application. (1) 4. Surface shall be completely dry prior to coating. Temperature shall be above 50 o F. (8) 5. Prepare sealant as recommended by manufacturer. 6. Apply sealant by a recommended method, such as by spraying using pump tanks or mechanical spray equipment, or by using notched or unnotched squeegees, rollers, or distributors. 7. The freshly sealed surface may have to be treated to retain acceptable skid resistance. Sealants that do not penetrate the deck surface usually require an immediate application of sand or other grit material that will embed into the sealant. Sealants that penetrate the deck surface may have to be blotted with sand until the sealant has been absorbed into the deck, temporarily increasing skid resistance. 8. Estimate cure and deck absorption times for the application method used and match lane closures and traffic control to these estimates. 9. Monitor procedures to maintain maintenance personnel safety in the handling and application of sealant chemicals, and to ensure that the natural environment beyond the bridge deck is not contaminated with any hazardous materials. Deck sealer is often applied as a part of concrete deck rehabilitation. (1) Runoff from sealing needs to be controlled to prevent contamination of waterways and property damage. (11) B Linseed Oil Treatment to Entire Deck The purpose of this activity is to reduce the intrusion of water and chlorides into the deck surface on bridges with B-2, low slump, or silica fume concrete decks. To be performed in hot, dry weather such as in July and August. (11) The linseed oil penetrates the fine pores in the deck and greatly reduces the permeability/ porosity of the deck. This provides freeze/thaw protection and reduces the chloride penetration into the deck. The linseed oil treatment is a total surface treatment, not a

48 crack treatment. Newly constructed bridges receive the first application of linseed oil by the contractor upon completion. A second treatment is applied about one year later by maintenance personnel. It has been shown that additional treatment after the second coat offer little additional benefit as only a small amount of the linseed oil penetrates the surface. Bridges several years old that show signs of scaling may benefit from an additional application of linseed oil. Should not be applied to worn or polished bridge decks. (11) Bridges to receive an application of linseed oil are identified by bridge inspection personnel. A list is created from which material quantities can be determined. (11) Equipment Sprayer or distributor Squeegee Materials: Boiled linseed oil Mineral spirits Sand (11) General Note: Procedures: 1. The deck should be completely clean and dry. Any loose dirt or dust should be blown off the deck immediately prior to the application of the mixture. 2. The material is applied using a sprayer or a distributor that has been thoroughly cleaned out. See table below for the proper application rate. The mixture is applied to half the deck at a time. The inside face and top of the barrier curbs shall also be treated. Traffic must be stopped while the material is being applied to prevent over spray on vehicles. DECK SURFACE CONCRETE APPLICATION RATE Silica Fume 0.02 gal/sy B gal/sy Low Slump 0.02 gal/sy 3. Mixture is 50% linseed oil and 50% mineral spirits. 4. Traffic must not be allowed on the wetted, slippery surface. The mixture is allowed to penetrate and dry. Areas that dry quickly should be sprayed with the hand sprayer to maintain an even coat. Puddles should be squeegeed to assist drying. Drying time is dependent on application rate, temperature, sunshine, humidity, and wind. Apply sand to surface to improve short-term skid resistance. 5. Traffic is allowed on the treated surface only when the surface is dry and traffic does not pick up the linseed oil. 6. Repeat treatment to the other half of the deck. 7. Excess sand shall be removed when the deck is completely dry. (11) 8. The mineral spirits and linseed oil mixture has a low flash point. Care must be exercised to prevent igniting the mixture by sparks, open flame or other means. In no case should the mixture be heated in a distributor. Spray must be controlled so not to get on passing vehicles or adjacent property. (11)

49 B Sealing Concrete Substructures Equipment Compressor w/hoses, etc. Backpack (handheld) sprayer Paint rollers & brushes Scrapers & stiff brushes Various handtools Sandblaster or Water-Blaster Barrel pump with hose & spray attachment Shovels & brooms Personal safety equipment Materials Water Blasting sand Sealer (silanes, siloxanes, silicones, and polymers) Procedures The following tasks are general steps typically associated with this maintenance activity. These tasks are not all-inclusive, nor always required. 1. Prepare work zone (i.e., traffic control, environmental protection, ladders & scaffolding, equipment). 2. Loosen and shovel off heavy dirt deposits. 3. Clean substructure elements by washing or using compressed air. 4. Sandblast or use stiff brushes and scrapers to loosen material if necessary. 5. The surface must be clean and dry, temperatures correct, and wind calm. (3) 6. Surface shall be completely dry prior to coating. Temperature shall be above 50OF. (8) 7. Apply sealer according to manufacturer's instructions. Begin sealing at the bottom of the element and work up, controlling application rate to avoid excess running. Use multiple coats, if necessary. (3) 8. Successive coats shall not be applied until preceding coats have become dry to the touch. (8) B.3.4. Painting Structural Steel Rust and corrosion are the greatest enemies of steel. When rust is allowed to progress without interruption, it may cause a disintegration and subsequently complete loss of strength in a bridge member. The corrosion also causes other problems such as pressure or friction between the surfaces. (4) An effective preventive maintenance measure to control rust and resultant corrosion of steel bridge members is to spot/zone paint exposed members. (2) Spot-Painting Guidelines: Spot painting involves painting damaged, repaired, or corroded members of a bridge where less than 35% of the paint on the bridge has deteriorated. Generally, if more than 35% of the bridge needs to be painted, the whole bridge should be painted since it will all need to be painted soon. The first consideration is to select a paint type compatible with the existing paint. Paint formulas are constantly changing, and many newer paints will not adhere, cover, or endure if applied over an older formulation. Generally, it is best to

50 spot-paint with the same type of paint already on the bridge. When this is not possible, consult the paint manufacturer s technical data to find a compatible paint. Whenever possible, spot painting should be done with a matching color to enhance the appearance of the bridge. Only the part of the structural member that has corroded is cleaned to bare metal, and only that part is given a prime coat, followed by a final coat. Equipment Power Chippers Power Brushes Sand Blasting Equipment Paint Brushes Rollers Sprayer Paint Thickness Tester Access Equipment Materials Paint Procedures 1. Power tools shall be used to clean corroded spots to bright metal. 2. Take measures to allay dust, if necessary. 3. Take measures to protect adjacent property, vehicles, pedestrians, concrete surfaces, and waterways. 4. Insure that temperature is above 45 o F, relative humidity is less than 85%, and surface is not hot or damp. Painting may be performed under cover in cold or damp weather. 5. Paint neatly with brush, roller, or sprayer. 6. Work paint into all crevices, if appropriate. 7. No coat shall be applied until preceding coat has dried. 8. Test thickness of paint. Note: Comply with applicable permit and procedural requirements of the Delaware Department of Natural Resources & Environmental Control (DNREC) in accomplishing this procedure and for containing and disposing of paint chips and sand. (8) B.3.5. Removing Debris from Waterway Channels This maintenance operation is performed to prevent scour and erosion of fills under abutments and piers. Removal of timber, debris and stream restrictions from waterways is necessary especially after heavy rainfalls and runoffs. Continued buildup of debris reduces the entrance area and increases the scour potential. The substructure is susceptible to debris or floating ice that forms drifts against its components. This can cause premature deterioration of these components and place excessive lateral loads on the whole structure. (4) Equipment Chain Saw Bush Ax Backhoe Front End Loader Winch or Pulling Equip Materials None Procedures 1. Remove debris collected around substructure. 2. Remove vegetation from stream banks and the streambed

51 3. Dispose of debris and vegetation properly. NOTE: Comply with all applicable permit and procedural requirements of the Delaware Department of Natural Resources & Environmental Control (DNREC) in accomplishing this procedure. (8) B.3.6. Extending or Enlarging Deck Drains This operation is performed to carry water discharge of drains away from supporting structure members. (10) Many structures which were constructed in the 1950's and 1960's were built with short deck drains at the gutter line that barely go through the deck. Most of these drains are located close to the facia beams (either on the inside or outside of these beams). Exposure to moisture, especially wind blown water, causes a fast rate of beam deterioration at these locations. A splash pad may be needed if the drain discharge extends beyond the limits of the inplace slope paving. (10) Bridge Maintenance Inspectors should become aware of situations which could be improved by installing drain extensions and recommend their use accordingly. Elimination of some of the existing deck drains (especially those causing slope paving scour) may be possible upon approval of the Engineer. (10) B Welded Drain Extension Equipment Welding Equipment Paint brushes Material Paint Procedure Installation procedure for extending bridge drains (when existing drain protrudes below concrete deck to allow welding) 1. Cut a box beam (203 mm x 152 mm (8 in x 6 in) or size as necessary to fit around the in-place drain) to the length required to extend the drain down to the bottom of the beam. Note: If clearance to the roadway is not critical, the drain should be extended 50 to 100 mm (2 to 4 in.) below the bottom of the beam. 2. Weld the extension piece to the inplace drain with 6 mm (1/4 in.) fillet weld (all around). 3. Grind the weld smooth and paint the drain. NOTE: A special nickel rod is necessary to weld the drain extension to the existing drain when cast iron and/or galvanized material is being welded. Also, see Figure B. 4 for lower angle bracket detail and its usage

52 Figure B. 4 B Bolted Drain Extension Using Straps Equipment Paint brushes Material Bolts and lock washers Paint Procedure Installation procedure for extending bridge drains (when the existing drain protrudes below the concrete deck a minimum of 25 mm (1 in.)) 1. Cut a box beam (203 mm x 152 mm (8 in x 6 in) or size as necessary to fit around the in-place drain) to the length required to extend the drain down to the bottom of the beam. NOTE: If clearance to the roadway is not critical, the drain should be extended 50 to 100 mm (2 to 4 in.) below the bottom of the beam. 2. Drill 4 holes (12 mm (1/2 in.) diameter) in the drain and drain extension. 3. Bolt straps to existing drain and drain extension respectively with 10 mm (3/8 in.) diameter by 25 mm (1 in.) long bolts with lock washers, etc. 4. Paint drain assembly

53 Figure B. 5 B Bolted Drain Extension Using Anchorages Equipment Drill Angle brackets Welding equipment Material Bolt anchorages, bolts, hex nuts and lock washers Angle brackets Procedure 1. Installation procedure for extending bridge drains (when existing drain does not protrude below the concrete deck to allow welding or bolting,) 2. Cut a box beam (203 mm x 152 mm (8 in x 6 in) or size as necessary to fit around the inplace drain) to the length required to extend the drain down to the bottom of the beam. NOTE: If clearance to the roadway is not critical, the drain should be extended 50 to 100 mm (2 to 4 in.) below the bottom of the beam. 3. Drill holes for and loosely bolt 2 angle brackets to the concrete slab and beams using 12 mm (1/2 in.) diameter bolt anchorages, bolts, hex nuts and lock washers. Weld the angle brackets to the drain extension

54 4. Mark the bracket locations on the drain extension and beam. 5. Drill holes in the drain extension, connecting bracket and beam for 12 mm (1/2 in.) diameter anchorage, bolts, etc. (Remove the brackets from the anchorages if necessary.) 6. Bolt the brackets and L76 x 76 x 6.4 (3 x 3 x ¼ in.) connecting bracket together. 7. Paint drain assembly. NOTE: A channel section (and in some cases PVC pipe) may be used in some cases in lieu of box beams. Figure B. 6 B.3.7. Repairing Damage from a Vehicle Hitting the Structure Regardless of the degree of severity of damage, loose concrete from a damaged girder has the potential to fall onto the road and could result in injury to motorists or damage to vehicles. (6) When damage to a concrete bridge girder occurs, the first action is to remove all debris on the road. It is also necessary to remove loose concrete and debris from the damaged girders. It may be necessary to provide wire mesh netting on the bottom of the damaged girder flanges to retain any fragments that become dislodged due to subsequent live load deflection. It may be necessary to post a load limit and utilize barricades or barriers to direct traffic away from the damaged area on the bridge. This is particularly necessary when the bridge rail is damaged, part of the bridge is no longer adequately supported by the girder, or there is structural damage to the deck. The requirement for barricades should be assessed at the time of initial inspection. (6)

55 While repair of damaged structural steel bridge elements may be unique and specific to the particular bridge element, standard techniques and procedures are provided for heat straightening, partial member replacement and repair of other defects. These techniques and procedures are carried out with minimal use of costly temporary shoring and supports and little disruption to the traveling public. (7) B.3.8. Lubricate Bearings This is primarily a periodic activity, with elapsed time between lubrications based on circumstances and conditions at each structure. Bearings below open joints require more frequent cleaning and lubrication than ones below sealed joints. The time between lubrications can also be revised as a result of bridge inspection reports. (8) All bearings having surfaces involving metal to metal movement where the metal surfaces are not permanently lubricated. The bearings can be located at abutements, piers, and in pin or pin and link assemblies for cantilever/suspended spans. (8) The work can include, but is not limited to, temporarily modifying superstructures to accept jacking loads, providing temporary supports for jacking; removing loads from bearings by either jacking from below or using needle beams from above; disassembling bearings; cleaning and lubricating all moving parts; reassembling bearings; and painting bearings with a prime coat. (8) Equipment Crane Jacks Wire Brush (8) Material Temporary Bent or Needle Beam Lubricate Paint (8) Procedure 1. Modify superstructure to accept jacking loads, if necessary. 2. Construct temporary bent or other supports for jack support or install needle beam. 3. Jack superstructure and remove the bearing assembly. 4. Disassemble bearing 5. Clean, paint and lubricate bearing. 6. Reassemble the bearing and reinstall the bearing. 7. Remove jacks or needle beams. (8)

56 B.3.9. Suggested Rainy Day Bridge Activities 1. Check bridge surface for ponding 2. Check bridges and box culverts for drift and erosion 3. Check drain basins at bridges 4. Clean abutment caps 5. Cut and treat brush and vines under bridges 6. Flush bridge decks (11)

57 Chapter C Bridge Repair And Rehabilitation

58 C. Bridge Repair and Rehabilitation C.1. Superstructure Related Work As discussed in chapter A, a bridge can be divided into the superstructure and the substructure. This chapter will discuss work on bridge elements in the same order and classification as in chapter A. Work on the superstructure as discussed in this manual is divided into work on: Deck elements Main load carrying elements Miscellaneous elements C.1.1. Deck Elements Work deck elements is classified here as work performed: The deck itself; and Deck railings and parapets. C Deck Repair Deck repair consists of repairing areas between the curbs of a bridge deck whether concrete, timber or steel deck with or without an asphalt overlay. Concrete decks often scale, spall and delaminate due to the effects of salt and the elements. They also develop cracks due to shrinkage and other causes. Timber decking usually 4" x 12" or 3" x 10" are subject to decay and cracking. They also come loose at times. Open or concrete filled steel grid decking sometimes cracks or becomes loose. (9) Use a chain drag to determine the limits of delamination. Repair of concrete decks include: 1) Deck Sealing 2) Crack repair 3) Partial depth repair of unsound concrete 4) Full depth repair of unsound concrete 5) Scale repair 6) Spall repair 7) Concrete Deck Patching 8) Repair of concrete deck overlaid with AC C Deck Sealing for details see Chapter B A. Crack repair A crack is a linear fracture in the concrete wearing surface that may only extend partway through the deck or it may occur as a failure plane running completely through the concrete structural element. The five types of cracks are as follows: longitudinal, transverse, diagonal, pattern or map, and random. (1) Longitudinal cracks are reasonably straight cracks running parallel to the centerline of the roadway. These cracks are usually caused by shrinkage, settlement, differential deflection of adjacent beams or girders, voids in the slab, or corrosion of reinforcing steel. (1)

59 Cracks classified as transverse cracks will appear in patterns roughly perpendicular to the centerline of the roadway. These cracks are usually caused by shrinkage, settlement, corrosion of the reinforcing steel, or deflection of the superstructure. (1) Diagonal cracks are similar to longitudinal and transverse cracks, but they tend to run at an angle to the centerline of the roadway. Frequently a bridge constructed on a skew angle to the centerline will exhibit diagonal cracks. (1) When an interconnected network of cracks appears, similar to the cracks that occur in dried mud flats, it is classified as pattern or map cracking. This normally results from improper curing of the concrete or a weakness in the concrete mix design. (1) If cracks are meandering, irregular, and have no particular form or direction, they are classified as random. (1) Isolated longitudinal, transverse, or diagonal cracks may be sealed. Wearing surfaces with severe cracking sometimes are overlaid with concrete in an attempt to seal the deck. One other categorization of cracks must be noted. Cracks may be either working (i.e., the crack is expanding and contracting, is growing in length, or is opening and closing, with elapsed time or with changing environmental conditions), or non-working (i.e., the cracks are stable in their character and extent of their existence). Non-working cracks may be filled and/or sealed with any material deemed suitable for the bridge s material and for the environmental conditions the bridge experiences. Working cracks, on the other hand, typically are more difficult to treat. Structural engineers need to assess the working crack for its danger to the structural member and to the bridge as a whole. If the crack is deemed to not present any immediate danger to the bridge, the cracking condition may be recorded and monitored for changes until such time as an engineering assessment suggests some treatment is needed. If the working crack is deemed to present a danger to the bridge, a structural engineering and an engineering material assessment should be undertaken to determine if the bridge member can be repaired or whether the cracked member should be replaced. (1) Cracks in the concrete deck that reach the reinforcing steel and have widths greater than about 0.18 mm (0.007 inch or the thickness of two sheets of paper) can allow moisture and associated chlorides to initiate and support corrosion of the reinforcing steel. Some experiences suggest that even epoxy-coated reinforcing steel will develop corrosion over an extended time if concrete cracks are left unsealed. Some common causes of cracking in a concrete deck are as follows: (1) Thermal stresses or drying shrinkage stresses. Defective aggregates that cause shrinkage or expansion of the concrete matrix. Too much water in the concrete mix. Insufficient or improper curing of the concrete. Bending and flexure stress in the deck. Movement between beams and girders supporting the deck. Bridge foundation settlement. (1) If small cracks exist over large areas, application of a liquid sealer to the entire deck surface may be an effective treatment to seal out moisture. (1) Large, open cracks that are no longer expanding may be treated by injecting a sealant (e.g., an epoxy- or polyurethane-based material). If the crack has passed completely through the deck, it will be necessary to seal off the lower surface of the crack before injecting sealant into the cracked area from above. To seal large cracks successfully by

60 injection, a clean crack (vacuumed, air-blasted, water-blasted, chemically washed, and flushed) is important. (1) If a crack is open and appears to be a moving crack, if a crack has been sealed before and has failed again, and if evidence of recent re-cracking exists, the crack is a working crack and may be sealed with a flexible crack sealant material. This usually requires routing a groove over the crack to hold the sealant and any recommended backer material. (1) In all crack-sealing operations for bridge deck maintenance, observe the following cautions: The cause of the cracking condition should be determined and corrected (if practical) at the same time. The crack surfaces must be clean and dry before sealing the crack. The depth of the seal should be less than or equal to the width of the seal. (1) Laboratory quality control tests suggest that gravity-fill polymer crack sealers effectively seal cracks in concrete bridge decks. With the wide variety of sealers available, a methodology has been developed to predict concrete sealer service life so that a reapplication interval can be estimated. At least experimentally, moderate full-depth cracking has been repaired by epoxy gluing narrow carbon fiber composite plates to the unfilled cracks. Fiber-reinforced materials used in deck patching also have the potential to seal cracks and to bridge over the crack in such a way as to return some of the structural strength lost by the cracked condition. (1) In composite deck systems, prestressing techniques can be employed to help close cracks in the deck. The repair consists of placing a tie rod across the deck crack. The tie rod is emplaced through drilled holes in the beams on either side of the cracked deck. The torquing nuts or turnbuckles on the tie rods are then tightened to close the crack in the deck (Figure C. 2). (4) Figure C. 1 External prestressing strands used to close a crack

61 Figure C. 2 Closing a crack in a deck using prestressing steel C Partial Depth Repair of Concrete Removal procedures should be restricted to methods which will not damage the structure. Modified boyer riveting hammers are commonly used to remove unsound concrete. Jackhammers heavier than 15 kg (30 lbs) should not be used for partial deck removal. Pointed bits should be used with caution. (10) Concrete removal should continue to a minimum depth of the top reinforcing bars, or until the exposed surface is sound concrete. Before removing the unsound concrete a minimum 25 mm (1 ) vertical saw cut is recommended for the perimeter of all areas designated for slab patching to provide a clean sharp edge for bonding. Care should be taken during the saw cutting to prevent damage to the reinforcing bars. Saw cutting is recommended, but other methods may be used if they can provide a 25 mm (1 ) vertical edge. (10) All exposed reinforcing bars shall be cleaned of all rust and concrete by sandblasting, so as to provide a tight surface but not necessarily to white metal. The concrete surface should be cleaned of all remaining unsound or fractured concrete by sandblasting. Spent sand and debris shall then be removed by air blasting. Place a concrete patching mix in accordance. (10) Figure C. 3 Deck Section Immediately prior to placing new concrete, the in-place concrete surface shall be sand blasted and then thoroughly cleaned with air blast. The air system shall have

62 a suitable oil trap in the air supply line between the storage tank and the nozzle. The surface of the in-place concrete that will be in contact with new concrete should be wetted and coated with bonding grout just before placing the new concrete. (10) The grout shall consist of equal parts by weight of Portland cement and sand (sand may be omitted) mixed with sufficient water to form a slurry whose consistency should be such that it can be applied with a stiff brush or broom to the in-place concrete, in a thin even coating that will not run or puddle in low spots. The grout slurry should not be so stiff that it forms globules when applied. The rate of progress in applying the grout slurry should be such that it does not become dry before it is covered with the new concrete. (10) Figure C. 4 Placement of Bonding Grout The concrete shall be vibrated and struck off at the level of surrounding concrete. Care should be taken not to over-vibrate the concrete. The patch should be finished with a wooden darby, floated with a magnesium float, and its edges sealed with epoxy penetrant after the patch has set up. After finishing, the patch should be textured with a medium or coarse street broom or tined in a transverse direction to centerline of roadway. (10) Figure C. 5 Tined Surface Finish Patches shall be sprayed with an approved membrane curing compound. A blanket of burlap and white plastic bonded together, called burlene, or wet burlap with white plastic sheeting held tightly in place should be placed on the patch as soon as the concrete is hard enough and will not be marked by the covering. (10) A concrete mix may be opened to traffic in 24 hours, provided the fresh concrete can be kept at a temperature above 15 C (60 F) which may require insulation in cool weather. 50 mm (2 ) slump concrete patches should be cured for a minimum

63 of 48 hours at temperatures of 15 C (60 F) and above, and for 72 hours if temperatures are below 15 C (60 F) prior to opening to traffic. No concrete patching should be done at temperatures below 5 C (40 F) unless an emergency situation exists. After the concrete patch has cured, seal its surface with an approved sealer. (10) Equipment Welding Equip. Concrete Mixer Air Compressor with Jack Hammer appropriate to depth to be removed (8) Material Reinforcing Steel Concrete (8) Procedure 1. Saw cut the boundaries of the deteriorated or damaged concrete to be replaced. Before sawing, use a pacometer to locate the reinforcing bars and anvil cutting them. 2. Remove deteriorated concrete with jackhammers. Cut and remove deteriorated reinforcing steel. Provide minimum 3/4" clearance around all reinforcing steel in top mat, regardless of concrete deterioration. 3. Place replacement reinforcing steel by tying into existing sound steel. 4. Place forms for concrete. Provide side forms including drip strip and chamfering as appropriate. 5. Erect the concrete screed and work platforms to permit finishing the plastic concrete at the proper elevation. 6. Pour concrete for a span or between construction joints in a continuous span in one continuous operation. 7. Finish and texture the deck and cure the concrete. 8. Remove forms. (8) C Full depth repair of unsound concrete Full depth removal shall be limited to those areas where deteriorated concrete extends thru the deck. Jackhammers that are heavier than 15 kg (30 lbs) are not recommended for full depth removal as the area of complete removal cannot be determined in advance. Pointed bits should be used with caution so as not to damage the rebars. Full depth removal is not recommended on delaminated areas. Sound concrete should be left in-place in conjunction with full deck removal. See Figure C. 6. (10) Concrete shall be vibrated, struck off and finished. Overnight lane closure is recommended for curing concrete

64 Figure C. 6 Full and Partial Depth Removal Figure C. 7 Formwork Support System for Full Depth Removal Figure C. 8 Alternate Formwork Support System

65 Immediately prior to placing new concrete, the in-place concrete surface shall be sand blasted and then thoroughly cleaned with air blast. The air system shall have a suitable oil trap in the air supply line between the storage tank and the nozzle. The surface of the in-place concrete that will be in contact with new concrete should be wetted and coated with bonding grout just before placing the new concrete. (10) The grout shall consist of equal parts by weight of Portland cement and sand (sand may be omitted) mixed with sufficient water to form a slurry whose consistency should be such that it can be applied with a stiff brush or broom to the in-place concrete, in a thin even coating that will not run or puddle in low spots. The grout slurry should not be so stiff that it forms globules when applied. The rate of progress in applying the grout slurry should be such that it does not become dry before it is covered with the new concrete. (10) The concrete shall be vibrated and struck off at the level of surrounding concrete. Care should be taken not to over-vibrate the concrete. The patch should be finished with a wooden darby, floated with a magnesium float, and its edges sealed with epoxy penetrant after the patch has set up. After finishing, the patch should be textured with a medium or coarse street broom or tined in a transverse direction to centerline of roadway. (10) Patches shall be sprayed with an approved membrane curing compound. A blanket of burlap and white plastic bonded together, called burlene, or wet burlap with white plastic sheeting held tightly in place should be placed on the patch as soon as the concrete is hard enough and will not be marked by the covering. (10) A concrete mix may be opened to traffic in 24 hours, provided the fresh concrete can be kept at a temperature above 15 C (60 F) which may require insulation in cool weather. 50 mm (2 ) slump concrete patches should be cured for a minimum of 48 hours at temperatures of 15 C (60 F) and above, and for 72 hours if temperatures are below 15 C (60 F) prior to opening to traffic. No concrete patching should be done at temperatures below 5 C (40 F) unless an emergency situation exists. After the concrete patch has cured, seal its surface with an approved sealer. (10) Equipment Welding Equip. Concrete Mixer Air Compressor with Jack Hammer appropriate to depth to be removed (8) Material Reinforcing Steel Concrete (8) Procedure 1. Saw cut the boundaries of the deteriorated or damaged concrete to be replaced. Before sawing, use a pacometer to locate the reinforcing bars and anvil cutting them. 2. Remove deteriorated concrete with jackhammers. Cut and remove deteriorated reinforcing steel. Provide minimum 3/4" clearance around all reinforcing steel in top mat, regardless of concrete deterioration. 3. Place replacement reinforcing steel by tying into existing sound steel

66 4. Place forms for concrete. Provide side forms including drip strip and chamfering as appropriate. 5. Erect the concrete screed and work platforms to permit finishing the plastic concrete at the proper elevation. 6. Pour concrete for a span or between construction joints in a continuous span in one continuous operation. 7. Finish and texture the deck and cure the concrete. 8. Remove forms. (8) C Total Replacement Of Concrete or Precast Deck Total replacement of a deck span is necessary when the concrete slab span has deteriorated and its load carrying capability has decreased. Where the bottom and/or ends of a "structural slab" are badly deteriorated, underpinning, total replacement or reconstruction is normally necessary. (10) When permanent slab repairs cannot be performed immediately and the roadway must be kept open to traffic, all areas which show weakness or are suspected of having low structural strength should be underpinned and maintained in a safe condition until permanent repairs can be made. (10) Procedure 1. Remove deteriorated concrete from area to be covered by new concrete seat. Drill holes into existing concrete footing and abutment wall for concrete anchors. 2. Place bent No.4 threaded bars (or 20 mm diameter bolts), horizontal rebars and form work, then pour concrete to provide a horizontal seat for the vertical columns. 3. Cure concrete for a minimum of 7 days. 4. NOTE: Steps 1,2 and 3 are only necessary if a concrete seat is required. 5. Secure HP 250 x 62 or equal vertical columns to front face of abutment wall with 20 mm diameter x 150 mm long anchor bolts. 6. Place a HP 250 x 62 or equal cap on top of the vertical columns and new steel beam sections (or other designated section) on top of the HP cap and beneath concrete slab. 7. Shim up between the columns, caps, and new beams using steel shims. 8. Field weld all connections that are not bolted. (10)

67 Figure C. 9 Half Transverse Section at Abutment Figure C

68 Figure C. 11 Figure C. 12 Enlarged Detail C Scale repair Scaling results when mortar and aggregate are gradually and continually lost over an area of the deck surface. If the surface is scaled to a depth less than about 6 mm (

69 inch), this is usually considered to be light scaling; a depth of about 6 mm to 13 mm (0.25 inch to 0.5 inch) is usually considered medium scaling; a depth of about 13 mm to 25 mm (0.5 inch to 1 inch) is usually considered heavy scaling; and a depth exceeding about 25 mm (1 inch) is usually considered severe scaling. Severe scaling is often the result of improper concrete construction methods rather than negligent preventive maintenance. Repair of light scaling on bridge deck surfaces is usually not necessary unless it affects the riding surface. Light scaling may be corrected by applying a concrete sealing membrane or other approved concrete surface sealant. Sealing the surface initially may be helpful in preventing the scaling condition from arising in the first place (see Chapter B). For any scaling condition exceeding a light scale, concrete repair procedures similar to those applicable to concrete pavement must be performed. When removing the deteriorated concrete, use care to avoid damaging any reinforcing steel. If the scaling results from chlorides penetrating the deck wearing surface, the deck needs to be monitored for further deterioration from chloride intrusion producing delamination of the structural concrete over the reinforcing steel. (1) However, if the scaling is due to poor concrete, scaling may progress downward resulting in deeper deterioration of the concrete which will require repairs. Because this type of problem is associated with concrete which did not have air entrainment, or which is weak or porous, full depth removal of the deteriorated area may be necessary in order to prevent future problems. A good repair of scaling is dependent on removal of all unsound material. Preparation of the area for patching, material requirements and curing should be the same as those covered in section(c (c) ). (10) Figure C. 13 Profile of Scaling C Spall Repair A spall appears as a depression resulting from a chunk of concrete, usually in a circular or oval shape, breaking loose from the concrete deck surface. Corrosion of the underlying reinforcing steel or deteriorated aggregate is usually the cause. If the spall is about 25 mm (1 inch) or less in depth or about 15 cm (6 inches) in diameter or less, it is considered a small spall. Dimensions exceeding this are usually considered large spalls, and their size begins to affect vehicular travel over the bridge. A hollowsounding area (a hollow sound produced when struck with a hammer or steel bar or when swept with a drag chain) indicates a fracture plane (or delamination) below the deck surface. When any spalling or delamination is suspected or evident, the entire deck area should be surveyed to determine the extent of spalling and delamination before beginning repairs. Since surveying a bridge deck interferes with traffic flow,

70 exposes maintenance personnel to traffic hazards, and is generally time-consuming and expensive, all aspects of the deck condition should be examined, if practicable, when conducting the survey. Survey aspects to be considered include the delamination survey, reinforcing cover survey, chloride content survey, and corrosion potential survey. The delamination survey covers rod sounding, hammer sounding, drag chain sounding, ultrasonic delamination detecting, etc. The reinforcing cover survey uses a magnetic field detector to estimate the depth of concrete over the reinforcing steel. The chloride content survey analyzes samples of concrete powder produced by drilling holes in the deck concrete over the reinforcing steel. The corrosion potential survey consists of electrical resistivity measurements with a halfcell probe; however, this is not an effective procedure when the deck contains epoxycoated reinforcing steel or contains galvanized coated steel, or if the deck surface has been treated with a dielectric material. (1) Once the extent and severity of the root cause of the spalled deck surface condition has been determined, an appropriate corrective action can be scheduled on the basis of the agency s guidelines and policies regarding whether the deck should be repaired with a maintenance treatment or scheduled for an overlay or replacement. If the deck is overlaid, use of low-slump dense concrete should be considered to improve resistance to moisture penetration. (1) Figure C. 14 The evolution of a spall Spall repair on bridge decks can be broken into three categories based on the overall condition of the deck, as is shown further into this paragraph. The

71 categories are identified according to the amount of spall, the extent of total deterioration (spall, delaminations, and corrosion potentials over volts), and total percentage of concrete samples containing at least 2 pounds of chloride per cubic yard of concrete: (4) (1) Extensive active corrosion. (a) Spall covers more than 5 percent of total deck area. (b) Deterioration covers more than 40 percent of total deck area. (c) Chlorides high in over 40 percent of samples. (2) Moderate active corrosion. (a) Spall covers from 0 to 5 percent of total deck area. (b) Deterioration covers from 5 to 40 percent of total deck area. (c) Chlorides high in 5 to 40 percent of samples. (3) Light to no active corrosion. (a) No spall present. (b) Deterioration covers from 0 to 5 percent of total deck area. (c) Chlorides high in from 0 to 5 percent of samples. (4) In many cases the identifying characteristics of the moderate category will overlap with the other two categories, and a best judgment based on engineering, economics, and other factors must be used to establish the appropriate repair for the bridge. (4) Concrete Deck Patching Deck deterioration requiring patching is usually caused by corrosion of the reinforcing steel. Patching is a temporary repair unless all of the chloride-contaminated concrete is removed before the deck is patched. If only the spalled and delaminated concrete is removed, the corrosion process continues and additional spalling will soon appear. Studies of deck-sealing practices suggest that while sealing or overlaying chloridecontaminated concrete will not stop the concrete s corrosion and deterioration, it can slow the process, which may be acceptable, depending upon the schedule of future major rehabilitation efforts, such as entire deck replacement. (1) Potholes in a deck sometimes require a temporary patch, while at other times a permanent patch may be best. They should not be allowed to remain without some action if they are severe enough to adversely affect the rideability of the deck or the safety of vehicles operating at normal speeds. In addition, the vertical acceleration of vehicles hitting potholes increases the impact loading on a bridge and can increase damage to other parts of the bridge structure. (1) Procedures to patch concrete decks should include the following steps: Evaluate surface areas to be patched, using hammers or a drag chain for hollowsounding delaminated areas (or using instruments to detect unsound areas). Outline the area to be patched with spray paint (or lumber crayon). A concrete saw is best for a rectangular area with square corners. Mark the area about 6 inches beyond the detected delamination to ensure coverage of all damage. (1) The saw cut is usually about 3/5 inch deep around the edge of the patch to provide a good vertical edge face. Monitor sawing to ensure that no reinforcing steel is cut. Saw operators should not cut beyond the patch area in the corners or a future spall

72 will form there. Patch areas that are within 2 feet of each other should be combined into a single larger patch. (1) Workers should use hand tools or pneumatic hammers weighing 30 pounds or less 15 pounds (at reinforcing steel level) at an angle of 45 to 60 to the deck, removing the concrete within the patch area. The patch area should be periodically sounded to ensure that the area and depth are correct and that all deteriorated concrete has been removed. If fracture lines are observed over a reinforcing steel bar, this indicates an area that will soon spall and should thus be removed. (1) The patch area should be thoroughly cleaned by sandblasting or water-blasting to remove loose concrete, rust, oil, or other materials that will prevent good concrete bonding. (1) Reinforcing steel will probably be deteriorated from any corrosion action. As a general rule, if the reinforcing steel bar has lost over 20% of its original cross section, new steel bars should be added by lapping, welding, or mechanically connecting them to the deteriorated bars. (1) Patching is often classified according to the depth of the patch required to make the necessary repairs. (1) Type A Patches only above the top layer of reinforcing steel. This type of patching may require special aggregate since the largest diameter of aggregate particles can not exceed the depth of the patch. If the patch depth is too thin for effective concrete patching and, simultaneously, too thick for epoxy mortar patching, then the patch depth may need to be increased to create an effective concrete patch. (1) Type B Patches from the deck surface to at least 1 inch below the top mat of the reinforcing steel. Type B patching will require removing enough concrete from under the reinforcing steel bars to permit fresh concrete to flow under the bars and to ensure that no voids exist. (1) Type C Patches to the full depth of the deck. If Type C patching is suspected to be required, ensure that preparations include gaining access to the deck s underside. Type C patching will require formwork to support the bottom of the hole. When any Type C patch exceeds a 4 feet 4 feet area, an engineer qualified to assess the structural implications should be consulted, determining if patching or some other rehabilitation action should be pursued. (1) When the fresh concrete is placed in the patch hole, the surface of the concrete to be patched should be damp but free of standing water. The patch concrete should be finished with a straightedge or float to produce a patch surface that is not more than 1/8 inch above or below the surrounding concrete surface. (1) If a patched area must be opened to vehicular traffic flow quickly, rapid-setting patch materials can be used. However, maintenance personnel must follow the manufacturer s or agency s specifications exactly while applying these materials because the quality of the patch is very sensitive to application condition control limits. (1) Any patching concrete mixed from scratch (not arriving at the job site in premixed sacks or containers) should be mixed in accordance with a design developed by a qualified materials engineer and with the agency s specifications. If large areas of a deck are being patched, a qualified bridge engineer should be consulted to determine if the patching process will adversely affect the bridge s structural capacity. (1)

73 Proper curing of the patch is important. If the cement being used is supposed to have a wet cure, ensure that the surface remains wet until it is opened to traffic. Membrane sealing cures may be appropriate. (1) C Polymer Deck Patching Polymer binder materials are not a commonly used patching material. Its main advantage is that it does not require a sawed hole. The maximum depth of the hole is generally limited to about 3/4 inch to 1 inch owing to high shrinkage of the material during the curing process. If neither an agency specification nor any manufacturer s recommendation is available for a mix, experience has shown that about one part epoxy polymer to four to seven parts of well-graded dry sand is a good epoxy-patching mix. Maintenance personnel should remember to add the sand to the epoxy polymer, rather than adding the epoxy polymer to the sand. (1) A variety of patching materials with a polymer base are available to maintenance agencies, if they are willing to purchase proprietary materials. Among the materials available, the unit cost of each material may vary considerably in any given location. Many of the materials available exhibit different characteristics in strength, durability, and cure times so that maintenance engineers and maintenance managers should research which material may best suit the agency need. The Advanced Civil Engineering Material Research Laboratory at the University of Michigan and the Michigan Department of Transportation have jointly conducted experiments using engineered cementitious composites (ECC) for patching bridge decks and for structural member repairs. Good initial results have been reported. (1) C Asphaltic Concrete Patching Asphaltic concrete is a porous material that will permit moisture (and any associated chloride ions) to reach the concrete deck and the reinforcing steel unless a waterproofing membrane is applied to the cleaned, exposed concrete before the asphalt is placed in the patch area. Patching a deteriorated area in a reinforcedconcrete deck with asphalt should be considered a temporary patch until a better time to apply permanent repairs becomes available. (1) C Emergency Temporary Patching Temporary repairs performed by maintenance forces, where rapid restoration of riding surface is required, may simply consist of filling the potholes or spalls with hot or cold mix bituminous. Bituminous patches are relatively inexpensive in cost and easy to place. However, bituminous patches may actually accelerate deterioration of surrounding concrete. Cold mix bituminous is used for emergency, cold weather repairs when concrete patches cannot be placed and a reasonably smooth riding surface must be maintained. Bituminous should be removed and replaced with concrete where a permanent repair is necessary. Bituminous patches may be used to extend deck life until (1) a protective overlay system is placed, (2) a bituminous

74 overlay is placed, (3) the entire deck is repaired with concrete, or (4) the deck is replaced. (10) Figure C. 15 A full-depth hole in the deck will often require emergency repair. Maintenance personnel must be cautious to keep traffic from moving across a bridge with a fulldepth deck hole unless it is clear (after consulting with a qualified engineer if necessary) that the hole is not a symptom of some greater structural weakness that may require closing the bridge for major rehabilitation and repair. If it is appropriate to make emergency repairs to the hole, it may be possible to hang plywood underneath the deck, allowing the hole to be filled with one of several proprietary materials that will develop high strength quickly, even in low temperatures. Sometimes steel plates can be bolted over a full-depth hole to provide an emergency cover. Steel plates have the disadvantage of creating a bump and a slick spot on the deck surface. In either type of emergency repair, the materials needed typically cannot be obtained on emergency notice. Therefore, advance planning is required so the necessary materials are available when needed. This type of emergency repair should be replaced by permanent repair or rehabilitation as soon as is practicable. (1) C Precast Concrete Deck Replacement Precast concrete tee beams, box girders, channels and concrete slab spans have "structural slabs" which support the wearing surface, the individual wheel load and also support the span. (10) Deterioration of these sections on the top surface and at keyways, concrete cracking and spalling at the rebars on the bottom side of the slab, and leakage of water through the slab are all items which require maintenance. (10) Rather than wait until repair of the structural slab is necessary (such as placing concrete patches on the bottom of a slab) preventive maintenance work is normally performed. This may entail removal of an existing bituminous overlay, cleaning out keyways between sections (for sectional type bridges), replacement of keyway grout and placement of an impervious or waterproof topping and wearing course. (10) Equipment Air Compressor with Jack Hammer

75 Welding Equip. Crane (8) Material Precast panel Section Epoxy Mortar or Concrete (8) Procedure 1. Precast deck sections or purchase from supplier. 2. Remove deteriorated concrete deck section with jackhammers. Cut and remove deteriorated reinforcing steel. 3. Prepare the abutments or beams for the precast units. 4. Place precast deck sections. 5. Fill stud void areas or panel connecting joints. 6. Grout keyways. (8) Figure C. 16 Precast concrete panels placed longitudinally

76 Figure C. 17 Precast concrete panels placed transversely C Timber Deck Repair Timber decks are usually the easiest type to repair. Broken, worn, or decayed planks can generally be replaced with little difficulty. When replacing them, nail the planks securely because loose planks increase future surface wear and create traction difficulties for vehicles. Plank or laminated timber decks can be fastened to steel I- beams, using metal fasteners or wood spiking pieces. A timber deck can be replaced by maintenance personnel relatively easily. Consequently, if a significant number of individual planks need to be replaced as part of the maintenance effort, the total lifecycle cost of material and labor may be reduced by replacing the entire deck, especially if an inspection indicates that further deterioration of individual planks will require more replacements in the near future. If an asphalt wearing surface is placed over the timber deck to improve surface traction and to improve the surface s ride quality, it must be frequently checked for needed maintenance. A deteriorated asphalt wearing surface over a timber deck may hinder more than help the deck surface s quality. (1) Equipment No Special equipment required (8) Material Pressure Treated Timber Spikes Anchor Plates Treated timber (8) Procedure 1. Remove and store deck mounted curbs, parapets, wheel guards and railing. 2. Remove existing deteriorated decking that can be repaired or replaced in the same day. 3. Clean and paint top flanges of stringers

77 4. Place pressure-treated lumber on the stringers parallel to the abutment. Lumber should be placed with the smallest dimension on the stringer. No stick shall bear on fewer than three stringers and joints should be staggered. 5. Spike each stick in place with spikes spaced as specified by the District Bridge Engineer. 6. Place Anchor plates spaced as specified by the District Bridge Engineer along every stringer, alternating sides of the stringer flange with every stringer. 7. Apply wood preservative to the ends of any stick that is field cut. 8. Place preformed membrane waterproofing if authorized by the District Bridge Engineer and place the bituminous wearing surface if authorized. 9. Replace deck mounted appurtenances (after wearing surface applied if applicable). (8) Figure C. 18 C Open Steel Grid Repair Remove and replace damaged portions of structura deck steel. To restore structural integrity of the deck, provide a smooth riding surface, and improve safety of the traveling public. (3) Material Steel shot Reinforcing steel Blasting sand Water Portland cement concrete (or other patching material) (3) Equipment Concrete saw 450-CFM compressor w/hoses, etc. Generator, Sandblaster Concrete mixer Pneumatic hammer (<30 lb)

78 Shovels & pickaxe Brooms & brushes Sounding hammer Various hand tools Personal-safety equipment Steel-short blaster (3) Procedure 1. Prepare work-zone (i.e., traffic control, environmental protection, equipment). 2. Identify and mark extent of damaged portions. Repair areas should be rectangular. 3. Saw cut outside the damaged area (straight cuts). 4. Remove deteriorated concrete using pneumatic hammers and hand tools to 1 in. below the steel. 5. Periodically sound the remaining concrete. 6. Clean the area using water-blasting or sandblasting. 7. Sandblast or wire brush exposed steel to remove rust and other contaminants. 8. Weld or mechanically fasten additional reinforcing steel to the existing steel if section loss is 20% or more. 9. Form underside of deck for any of full-depth repairs. 10. Apply a bounding agent of neat cement paste or 1:1 sand-cement grout mix to remaining concrete, if necessary 11. Place new concrete or patching material (depending on repair depth). 12. Broom-finish surface of the patch. 13. Provide for proper cure to avoid shrinkage cracks. (3) C Concrete Sidewalk Repair Since sidewalks facilitate the safe movement of pedestrians over a bridge, the surface needs to be maintained so that people do not encounter any surface hazards. In concrete sidewalks, cracks should be sealed; spalls or potholes need to be filled; scaled areas need to be resurfaced for a smooth, well-draining surface; joints need to be kept sealed to minimize any tripping potential; and surface drainage needs to minimize any surface ponding of water (which may form ice patches in freeze-thaw climates). While sidewalk deterioration can be reduced by applying a surface sealant, any sealant should be applied in such a way that the surface retains good traction for pedestrians during wet weather. Where steel plates or steel grating is used for sidewalks, regularly check for any loose fasteners, ensuring that the surface is not slippery for pedestrians when wet (a sand, aluminum oxide, or other abrasive coating may be added to improve skid resistance). Asphaltic concrete sidewalk surfaces are often overlaid on Portland cement concrete, and as such, need to be maintained so that raveled spots, potholes, and cracks do not present pedestrians with difficulties or hazards. Timber deck sidewalks need to be inspected for cracks, warped areas, rotted areas, or knothole openings that can create pedestrian difficulties; when such defects are observed, the deteriorated planking needs to be replaced as soon as practicable. In urban areas, police agencies often inform maintenance agencies of any areas where vandalism associated with pedestrians throwing objects from bridges has been

79 reported. To reduce such vandalism, maintenance agencies can consider adding chain-link fencing to sidewalks and bridges. (1) Equipment Air Compressor with Hammer Welding Equip. (8) Material Concrete Reinforcing Steel (8) Procedure 1. Remove existing deteriorated sections of sidewalk to sound concrete. 2. Place replacement reinforcing mesh or bars by tying them into reinforcing in sound concrete. 3. Place forms for concrete. 4. Place and cure concrete. (8) C Concrete Curb/Parapet Repair Problems with concrete curbs include freeze-thaw deterioration, deterioration from de-icing chemicals, spalling at expansion joints, cracking, and deterioration from corrosion of reinforcing steel or anchor bolts. Deteriorated concrete should be removed down to good concrete (even if the entire curb section must be removed), the area thoroughly cleaned (sandblasted if needed), and a patch applied. Spalling is often associated with expansion joint movement, so in the repair process additional clearance for longitudinal movement should be provided. Cracks often appear as transverse cracks in adjacent deck paving or adjacent sidewalk paving. Minor cracks can be sealed with a waterproofing sealant material. Where reinforcing steel and anchor bolts are encountered in curb repair, if corrosion has caused the bar or bolt cross section to be reduced, they should be replaced with new bars or bolts in the concrete repair process. Preventive maintenance includes regular deck flushing, treatment of curbs with waterproofing sealants in snow and ice climate areas, and good deck joint maintenance. (1) The work area may also includes the slab directly underneath and adjacent to the curbs or parapets when minor repairs or adjustments must be made to the slab to accomplish this activity. The work can include, but is not limited to, removing deteriorated or damaged concrete and reinforcing steel; drilling and grouting or otherwise securing dowels into existing concrete; placing and tying reinforcing bars; constructing forms; and placing new concrete. (8) Equipment Crane Air Compressor with hammer (8) Material Precast parapet section Epoxy mortar Anchorage system (8) Procedure 1. Remove existing deteriorated section of parapet and curb with light hammer

80 2. Level deck in parapet location and drill holes for anchors into deck. Do not penetrate deck unless approved. 3. Set section of parapet on a leveling bed of mortar to bring the parapet into proper line. 4. Install threaded insert with grovor approved adhesive (Method I). Insert galvanized bolts, washers, and nuts and tighten sufficiently to retain poured grout through the access hole (Method II). Permanently tighten nuts (Method II) or grout after bolt is tightened (Method I). 5. Pack bolt pocket with non-shrink, nonstaining mortar. (8) Figure C

81 C Railing/Parapet Repair C General Railings: Railings include any barrier or parapet that runs parallel with the traffic on either side of the bridge. Avoid leaving the end of a bridge rail or a parapet wall exposed to traffic flow. If a bridge rail or barrier has been identified as substandard, at the first rehabilitation opportunity practicable consider upgrading it to the current applicable standard as part of the rehabilitation activity. Repair collision damage to railings as soon as possible. Since major collision damage to a section of railing may make complete replacement of the entire run of railing more cost-effective than repair, any substandard railing should be considered for an upgrade replacement in such a situation. (1) Some different types of railings are concrete railing, steel pipe and tubular railing and W-beam railing. Some are defined below: C Conncrete Railings: Like concrete decks, concrete railings are susceptible to cracks and spalls from de-icing chemical damage. Sealing cracks and applying surface sealant as is done to decks is helpful in minimizing needed maintenance. If a sealant is applied to a concrete railing soon after construction is completed, as a preventive measure use of a sealant containing a light-reflecting material should be considered to enhance driver awareness of the bridge railing. When one or more sections of a concrete railing have been broken (assuming a replacement with concrete will be done), remove the damaged sections of post and rail with a jackhammer and acetylene torch; straighten or position existing reinforcing steel as needed; splice and replace reinforcing steel as needed; form new concrete sections to conform with rail dimensions as shown on the original construction plans; place and properly cure the concrete; finish the concrete as needed with a rubbing stone to match the existing rail and seal; and clean up the job site to remove any traffic hazard debris. Maintenance inspections need to pay particular attention to the joints of any electrical conduit in a concrete railing because differential expansion can create conduit breaks. (1) C Steel Pipe and Tubular Railings: Steel pipe and tubular railings are susceptible to collision damage, loose anchor bolts and connections, corrosion damage, and weaknesses resulting from original design deficiencies. Corrosion damage is minimized by using galvanized materials in the original installation (or in repair replacement) and a zinc-rich paint to coat any parts not galvanized. Repair and replacement typically consists of straightening any collision-damaged components for which replacement is not deemed necessary; installing a temporary railing with traffic warning devices if the repair and replacement process cannot be completed quickly; tightening all loose anchor bolts and connections; painting any corroded areas with zinc-rich paint; cleaning and painting any rusted areas where posts or anchors enter concrete; replacing any railing components for which corrosion has significantly reduced the structural cross section; repairing or replacing all damaged anchor bolts; welding any anchor bolt extension at a point below the finished surface of

82 the concrete to which it is anchored; replacing any damaged concrete or concrete removed to perform repairs; and conducting touch-up painting of any connections after final tightening of nuts and connections (hot-dip galvanizing is preferred to painting when practical). (1) C Aluminum Railings: Aluminum railings are susceptible to collision damage, anchor bolt and connection damage, oxidation (aluminum corrosion), and original design inadequacies. Because aluminum is a more chemically reactive material than most other structural materials, oxidation protection is required at the contact surface with other materials. Steel-to-aluminum contact surfaces should be caulked with an elastic, non-staining blend of water-repellent oil, asbestos fiber, and flakes of aluminum (metal or other suitable materials). The contact surface of each aluminum railing post attached to concrete should be separated from the concrete with a non-reactive bedding material such as 14-kg (30-pound) non-perforated, asphalt-saturated felt; galvanized or painted steel plate; or an elastomeric caulking compound. General repair procedures include repairing or replacing any collision damage to return the railing to its original design strength (new railing rather than repair of damaged sections is usually better because of the skill level needed to properly straighten or weld aluminum). Anchor bolts and connections should be inspected and repaired in the same manner as is done for steel railings. When the damaged area is extensive, the possibility of replacing an aluminum railing with a New Jersey type concrete railing should be considered for maintenance and safety considerations. (1) C Railing Replacement With W-Beam When existing bridge railing has been damaged or deteriorated to an unsafe condition. (10) Procedure 1. Remove existing rail system. 2. Drill holes in concrete slab for 19 mm (3/4 ) diameter concrete anchors and 19 mm (3/4 ) diameter bolts. 3. Bolt W 150 x 22 posts to concrete with 19 mm (3/4 ) diameter bolts. 4. Bolt two W-beam guardrails to TS 125 mm pipe using 16 mm (5/8 ) diameter bolts, nuts and washers. (10) NOTE: TS 125 mm (5 ) OD x 3.2 mm (1/8 ) thick pipe to be shop welded to W 150 x 22 pipe with 5 mm (1/5 ) fillet welds. (10) Figure C. 20 Outside Elevation

83 Figure C. 21 Figure C. 22 C Bridge Parapet Repair When damage is extensive, temporary installation of signs, lights, barricades or other safety/warning devices may be required. (8) This activity involves repairing or replacing all or portions of a parapet mounted metal railing. The work can include, but is not limited to, removing damaged or deteriorated portions of the railing; placing and securing anchor bolts preparatory to placing concrete; drilling and grouting or otherwise securing anchor bolts into

84 hardened concrete: installing railing; and cleaning railing after installation is completed. (8) Equipment 30 Lb. Hammer Welding Torch Equipment Concrete Drill (8) Material Concrete Replacement Railing (8) Procedure 1. Remove damaged or deteriorated section of existing parapet mounted metal rail, salvaging reusable parts. Flame cutting may be necessary. 2. Remove concrete around damaged anchor bolts with a 30 lb hammer. 3. Cast new concrete to original lines. 4. Drill holes in concrete for anchor bolts. 5. Install anchor bolts with grout or approved adhesive. Fill any remaining space with epoxy material. 6. Prior to installation, thoroughly coat surfaces of aluminum in contact with other metals, stone masonry, or concrete with caulking compound. 7. Install new railing. 8. Burr threads on anchor bolts to prevent loosening of nuts. 9. Clean railing with an acceptable solvent (8) Figure C

85 C Structure Mounted Railing Repair When damage is extensive, temporary installation of signs, lights, barricades, or other safety/warning devices may be required. (8) This activity involves repairing or replacing all or portions of a structure mounted railing. The work can include, but is not limited to, removing damaged or deteriorated railing; repairing or replacing elements of metal railing; placing and securing anchor bolts preparatory to placing concrete; drilling and grouting or otherwise securing dowels or anchor bolts into hardened concrete; construction forms, installing reinforcing bars and placing concrete in concrete posts and railing elements; and installing metal railings. (8) Equipment 30 lb. Hammer Concrete Drill Hammer and Chisel (8) Material Replacement Rail Elements or sections Concrete Anchor Bolts (8) Procedure 1. Remove damaged or deteriorated structure mounted railing. 2. Remove elements of the structure as necessary, salvaging reusable parts. 3. Remove concrete around damaged anchor bolts with a 30 lb hammer. 4. Cast new concrete to original lines in concrete parapets or to match existing lines for metal rails. 5. Drill holes in concrete for replacement anchor bolts. 6. Install anchor bolts with grout or an approved adhesive. 7. Prior to installation, thoroughly coat surfaces of aluminum in contact with other metals, stone masonry, or concrete with caulking compound. 8. Install new railing. 9. Burr threads on anchor bolts to prevent loosening of nuts. 10. Clean railing with an acceptable solvent. (8) NOTE: Details of repair/replacement of structure mounted railing should be provided by the District Bridge Engineer. (8)

86 Figure C. 24 Typical Section-Existing Parapet C Steel Guiderail Mounted to Concrete Figure C. 25 Structure mounted guide rail installation

87 Figure C. 26 C Steel Guiderail Mounted to Steel Beam Figure C

88 C Pedestrian Railing Repair When damage is extensive, temporary installation of signs, lights, barricades or other safety/warning devices may be required. (8) This activity involves repairing or replacing all or portions of a pedestrian railing. The work can include, but is not limited to, removing damaged or deteriorated railing; salvaging reusable parts; repairing or replacing elements of the railing; placing and securing anchor bolts preparatory to placing concrete; drilling and grouting or otherwise securing anchor bolts into hardened concrete; and installing railing. (8) Equipment Air Compressor Concrete Drill (8) Material Replacement Rail Elements or sections Concrete Anchor Bolts (8) Procedure 1. Remove damaged or deteriorated pedestrian railing. 2. Repair or replace elements of the railing as necessary, salvaging reusable parts. 3. Remove concrete around damaged anchor bolts with a 30 lb hammer. 4. Cast new concrete to original lines. 5. Drill holes in concrete for replacement anchor bolts. 6. Install anchor bolts with grout or approved adhesive. 7. Prior to installation, thoroughly coat surfaces of aluminum in contact with other metals, stone masonry, or concrete with caulking compound. 8. Install new railing. 9. Burr threads on anchor bolts to prevent loosening of nuts. 10. Clean railing with an acceptable solvent. (8) C Median Barrier Repair When damage is extensive, temporary installation of signs, lights, barricades or other safety/warning devices may be required Small areas of deck directly at the barrier which require minor amounts of leveling or surface preparation to permit satisfactory repair or installation of the barriers are also included in this activity. This activity involves repairing or replacing all or portions of a median barrier. The work can include, but is not limited to, removing damaged or deteriorated median barrier; salvaging or replacing parts of a metal barrier; placing and securing anchor bolts preparatory to placing concrete; drilling and grouting or otherwise securing anchor bolts or dowels into hardened concrete; constructing forms for concrete median barriers; placing concrete; and installing metal railing. (8) Equipment Crane Air Compressor with Hammer (8) Material Precast parapet Section

89 Epoxy Mortar Anchorage System (8) Procedure 1. Remove existing deteriorated section of median barrier with a 30 lb hammer. 2. Level deck in barrier location and drill holes for anchors into deck taking care not to punch through if through bolts are not to be used. 3. Set section of barrier on a leveling bed of mortar to bring the barrier into proper line. 4. When using through bolts, insert galvanized bolts, washers, and nuts and tighten sufficiently to retain grout poured through the access hole. If screw anchors are used, permanently tighten nuts after the anchor and bolts are grouted in and grout has set. 5. Pack bolt pocket with non-shrink mortar. (8) C Chain Link Fence On Concrete Rail This repair procedure is for lowering fence posts of chain link fences that are placed in pipe sleeves on concrete rail bases and have been forced up by freeze/thaw action. (10) Procedure 1. Detach fencing ties and remove post. 2. Probe or drill open the weep hole. 3. Remove remaining foreign materials from weep hole and pipe sleeve cavity with compressed air or water. Suction forces may be necessary in removing the foreign material. 4. Lower post down to its original position. 5. Caulk around post at pipe sleeve with an approved caulking compound. (10)

90 Figure C

91 Section C.1.2 Main Load Carrying Elements C Repairing Load carrying Steel Members C Temporary Concrete Slab Support During Beam Replacement C Repair of Shallow Nicks and Gouges in Steel Members C Repair of Structural Cracks in Steel Members C Repair of Damaged Flange/Web of Steel Beams C Repair of Overloaded Steel Beams C Repair of Damaged Steel Beam at Bearing Locations C Repair of Bent Steel Beams (Heat Straightening) C Straightening Deformed Webs of Steel Beams C Replace Steel Stringer C Repair/Replace Steel Floorbeam C Repair of Steel Girders C Repair Steel Diaphragm/Lateral Bracing C Repairing Load Bearing Concrete Members C Introduction C Repair of Spalled Areas of Concrete Beams and Stringers C Repair Prestressed Stringer (Post-Tensioning) C Repair or Replacement of Reinforced or Prestressed Concrete Diaphragm C Repair of Reinforced or Prestressed Concrete Members Other Than Stringers or Diaphragms C Truss Repair C Introduction C Replacement of a Vertical Tension Member C Replacement of a Vertical Tension Member C Replacing Vertical Compression Members C Straightening a Steel Truss Member C Repair of Damaged Lower Chord Members C Tighten or Shorten Eye-bar and Rod Truss Tension Members Using Flame Shortening C Strengthening Bottom Chord by Post-Tensioning C Strengthening Top Chord Member C Repair of a Floor Beam C Strengthen Entire Bridge Cable Sling System C Strengthen Entire Bridge Cable-Stayed Additional Support System C Strengthen Entire Bridge Shifting Supports C Strengthen Entire Bridge Addition of Support C Strengthen Entire Bridge Method of Subdivision C Strengthen Truss Connections and Braces C Increasing Vertical Clearance by Modifying the Portal Bracing

92 C Repair of Timber Members C Introduction C Temporary Repair of a Deteriorated Timber Beam C Repair of a Split Stinger C Repair of Decayed Stinger Ends C Repair/Replace Timber Stringer From Under the Deck C Repair/Replace Timber Stringer From Above the Deck C Repair of Timber Connections

93 C.1.2. Main Load Carrying Elements Work on the main load carrying elements is divided here according to the material the element is made of: Steel Members Concrete Members Truss Members Timber Members C Repairing Load carrying Steel Members Introduction The three general types of damage experienced in steel beams are corrosion damage, impact damage, and fatigue damage. Good maintenance practices can prevent or drastically limit corrosion damage, but if corrosion is allowed to develop it can reduce a bridge s load-carrying capacity as much as any other type of damage. Repairs to steel beams frequently require adding structural material, such as plates or angles, to provide structural strength that compensates for the damage. Because of poor experience with field-welding added material to a steel beam, some agencies prefer to bolt additional steel material to increase the strength of a damaged beam. If a repair to a steel beam is at a location where a fatigue failure is unlikely and if the weld quality can be highly controlled, good performance can be obtained from field-welding. (1) C Temporary Concrete Slab Support During Beam Replacement Damaged steel beam must be removed and deck must be temporarily supported from pier to pier (or other supporting units). Procedure 1. Determine the size of temporary support beam and hanger spacing with the Office of Bridges and Structures. 2. Place wood support blocks and shim system on the pier seats between top of pier and bottom of slab. 3. Place two wood blocks on top of concrete slab directly above each wood block system. 4. Place a steel beam (designed to carry loads) on top of wood blocks. 5. Place simultaneously 38 mm x 89 mm diagonal wood braces from the wood blocks up to the top flange on each side of the beam. 6. Locate and drill 38 mm diameter holes through the concrete for 25 mm diameter hanger rods. 7. Place hanger rods, support plates and wood blocks beneath slab and support plate above beam. Tighten rods alternately in equal amounts

94 Figure C. 29 Longitudinal Section Figure C. 30 Method of Supporting Slab During Repair Operation

95 Figure C. 31 Section at Railing and Sidewalk Figure C. 32 Section at Slab

96 C Repair of Shallow Nicks and Gouges in Steel Members If a steel member has been damaged to a maximum of 5 mm thickness. Procedure 1. Grind out the defect, blending the edges of the defect into the surface of the surrounding material at a 1 vertical to 12 horizontal maximum slope. 2. Prime and paint the exposed surface. (10) Figure C. 33 C Repair of Structural Cracks in Steel Members If a steel member has developed a structural crack, yet is repairable. Procedure 1. Notify the Office of Bridges and Structures immediately of the structural cracks. 2. Locate and determine the length and depth of the cracks using one of the following inspection methods: a. Magnetic-partic1e b. Dye penetrant c. Ultrasonic 3. Core a minimum of 20 mm diameter hole through the member at the ends of the crack. See Figure C. 34 through Figure C. 37. Test either the cored section ("coupon") or inplace steel to ensure end of crack has been arrested, and/or send coupon to Structural Metals for testing. 4. Prime and paint the exposed surface (10)

97 Figure C. 34 Repair of a Web Stress Crack Figure C. 35 Hole Location Includes Crack Tip Figure C. 36 Hole Location Does Not Include Crack Tip Figure C. 37 Hole Location Does Not Include Crack Tip C Repair of Damaged Flange/Web of Steel Beams When portions of a beam are damaged beyond repair and must be replaced. The beam must be a weldable steel. Procedure 1. Support the beam and its load by means of support system details as shown in C

98 2. Remove the damaged portion of the beam by flame cutting along marked lines. The marked lines should be placed above the beam neutral axis except at the ends of the cut. 3. Grind smooth the flame cut edges and sides of the beam to receive the weldment. 4. Cut the replacement part from a steel beam which is equal to or greater than the inplace beam. Make the replacement part the exact shape of the removed section. 5. Obtain a weld procedure. During the welding process the bridge should be closed to traffic. 6. Grind the weld smooth and flush with the original surface. 7. Paint the exposed surface. (10) C Repair of Overloaded Steel Beams When a beam is overloaded due to excessive dead load, live load or deteriorated section of beam. Procedure 1. Relieve the dead load stress on the beams by uniformly jacking the beams up at midspan. 2. Center channels on one or both sides of beams and drill holes through the beams and channels for high strength bolts. 3. Bolt channels and beam together with high strength bolts beginning at the center of the span and working toward the abutments. 4. Progressively lower jacking system to insure equal distribution of dead load to the beams. Figure C

99 Figure C. 39 C Repair of Damaged Steel Beam at Bearing Locations When Corrosion has badly damaged a beam at its bearing area and a portion of the beam must be replaced. Beam must be weldable steel. Equipment Jacks or Carrier Beams Sand Blaster Cutting Torch Welding Equip. (8) Material Temporary Bent New Section Prime Coat Paint Sand (8) Procedure 1. Support the beam and its load by means of support system details as shown in C Remove the damaged area and bearing stiffeners by flame cutting along marked lines using curved comers to eliminate notch effect. 3. Cut a steel section from a beam or tee with thickness equal to or greater than the removed section. Make the replacement beam part the exact shape of the removed section. 4. Obtain weld procedure from Structural Metals Unit and weld accordingly. 5. Check welds with dye penetrant. 6. Prime and paint the exposed surface. (10)

100 C Repair of Bent Steel Beams (Heat Straightening) When a steel member has been bent but can be straightened using heat and mechanical force. Impact damage to steel beams from over-height vehicles is a common problem. Many agencies use a heat process to straighten beams if the amount of beam deformation is not excessive. If the steel properties are well-known, it is possible to apply heat to the beam with oxyacetylene torches in such a pattern that the repetitive heating and cooling of the steel will cause an expansion and contraction of the metal, working the deformation out of the beam. The original properties of the steel have to be such that treating the beam in the field to remove the deformation does not also reduce the strength required in the original bridge design. Thus, a professionally qualified structural engineer should design and monitor the procedure. The damaged area needs to be inspected very carefully before, during, and after the repair process to identify any flaws, tears, or cracks. The heat and the resulting forces in the beam need to be applied in such a way that the warping stresses to reshape the beam result in gradual beam movement rather than any abrupt new distortion that may tear the steel s molecular bond. The total quantity of heat applied to the beam needs to be controlled so that the steel is not heated above about 1200 F to avoid damaging its material properties. Heat sticks can be used to indicate when the steel reaches the maximum allowable temperature. Anytime a steel member is bent and deformed, the steel has been stressed beyond its yield point and its mechanical properties have been altered even if no cracks or tears appear. When a bent steel beam is straightened, the increase in the working of the molecular structure reduces the steel s ductility, making it more susceptible to fatigue failure. Thus, even if a qualified structural engineering assessment indicates that a beam was designed with excess load-carrying capacity that negates the need for strengthening

101 modifications, the inspection process following beam straightening should emphasize checking for cracks or other signs of subsequent weaknesses. It is important to have a qualified bridge structural engineer determine whether it is sound practice to straighten and repair bridge damage, or whether the appropriate alternative is to replace the damaged members. Veksler reports that, after a semi-trailer and its tractor crashed into the Tacony-Palmyra Bridge near Philadelphia, an engineering assessment indicated that the damaged steel members needed to be replaced rather than repaired. (1) Figure C. 40 Locations, size, and sequence of heat application for flame straightening Figure C. 41 Torch paths for various shapes Procedure 1. Place an 191 mm x 191 mm (minimum size) diagonal timber brace between adjacent beams

102 2. Using a jacking device (as detailed in Figure C. 42 thorough Figure C. 44) placed against the bottom flange of straight beam, braced against as many beams as necessary, jack the bent beam back to its original position, utilizing heat placed on the beam. Correct methods of applying heat are given in Figure C. 40 and Figure C Paint exposed areas of steel. (10) Figure C. 42 Typical Arrangement of Jacking Device Alternative 1 Figure C. 43 Typical Installation of Come-a-long Alternative 2 Figure C. 44 Schematic Drawing of Device for Applying Auxillary Straightening Load to Bent I- Beam Alternative

103 Figure C. 45 Technique for Supporting Bridge During Mechanical Straightening of Damaged Steel Beam Figure C. 46 Jacking Device Detail

104 C Straightening Deformed Webs of Steel Beams When the web of a steel beam is deformed and must be straightened. Procedure 1. Bolt a horse collar (U shaped) bracket to the web on either side of the deformation. 2. Place a flattener plate against the other side of the web (brace against adjacent beam with diagonal wood member). 3. Place another flattener plate inside of horse collar bracket and jack the deformation out of the web. 4. Remove jack and flattener plates. Remove horse collar bracket. 4. Grind the web surface smooth and check for cracks using dye penetrant inspection. 5. Prime and paint exposed areas of steel as per painting section (.700) of this manual. (10) Figure C. 47 Device for Straightening Web Deformations C Replace Steel Stringer The addition or replacement of a stringer is normally performed in conjunction with the replacement of the deck. If the deck is not removed the member must be replaced from under the bridge. The beam replacement method will depend upon whether the beam/deck system is composite or noncomposite. (4) Equipment Welding Torch Jacks or Carriers Beams Crane or Lift Equip. (8) Material Temporary Bent

105 Replacement Members H.S. Bolts Prime Coat Paint Reinforcing Steel Concrete Mix Formwork (8) C Noncomposite Beams 1. Modify superstructure to accept jacking loads, if necessary. 2. Place jacks under the deck or under the beams that are not being replaced and jack the deck off the beam to be removed. 3. Remove beam or repair the damaged end of the beam. The beam may be cut to facilitate removal. The beam may be jacked out of position or a lift truck used to lower the beam. 4. Lift or jack the replacement beam into place. To use a lift truck or cable system, a hole must be cut or drilled into the deck to run the cable through. 5. Position the beam on the bearing plates, jack the deck down onto the new beam and check for distress in the beam and deck. 6. Remove jacks, temporary supports, and repair any holes in the deck. (4) 7. Clean and paint. 8. Repair deck if necessary. C Composite Beams 1. Modify superstructure to accept jacking loads, if necessary. 2. Use jacks to lift the composite beam off its bearing. 3. Burn or cut the lower portion of the beam (web and bottom flange) from the fixed top flange. 4. Grind the cut area of the top flange smooth. 5. Weld a new stringer to the old stringer top flange for continuity. (4) 6. Clean and paint. 7. Repair deck if necessary. Figure C. 48 Replacement of a steel beam in a composite section C Repair Steel Floorbeam Based on need as indicated by bridge inspections. When deterioration is so severe that the structural capacity of a floorbeam is impaired, special traffic controls may be required. (8)

106 All rolled beam and built-up, riveted or welded floorbeams, their connections to girders, chords or bearings; stringer connections to floorbeams; and areas of the deck directly adjacent to floorbeams requiring repair or replacement. (8) Repairing or replacing all or portions of steel floorbeams. The work can include; but is not limited to, providing temporary supports for jacking; temporarily supporting the ends of floorbeams or the loads from stringers supported by floorbeams either by jacking from below or using needle beams from above; disconnecting floorbeams from their supports, or stringers from their beams by removing bolts or rivets or using oxy-acetylene cutting torches; prefabricating replacement members or elements; drilling and reaming holes: grinding to provide the required finish or tolerances on steel surfaces; making minor repairs to decks within the work area; erecting replacement or repaired elements and incidental items in the work area by welding or high tensile strength bolting; and preparing surfaces which have been damaged or left bare by the work, and applying a prime coat of paint. (8) Equipment Jacks Carrier Beam Beam Cutting Torch Welding Equip (8) Material Beam Sections Paint (8) Procedure 1. Modify superstructure to accept jacking loads, if necessary. 2. Construct temporary bent or install needle beam under sound portion of superstructure. 3. Lift superstructure. 4. Remove damaged or deteriorated section. 5. Weld new section into place using full penetration groove welds. 6. Lower member and check for distress 7. Remove lifting devices. 8. Clean and apply prime coat paint. (8) C Repair of Steel Girders Based on need as indicated by bridge inspections or reports of accidental damage. If damage or deterioration is sufficiently severe so that the structural capacity of a girder is impaired special traffic controls may be required on an emergency basis. (8) Includes all built-up girders, riveted or welded; their connections to floor beams, incidental items such as cross frames and bearings; and areas of the deck directly adjacent to girders requiring repair. (8) Equipment Jacks or Carrier Beams Welding Equip (8)

107 Material Temporary Bent New Section Prime Coat Paint (8) Procedure 1. Modify superstructure to accept jacking loads, if necessary. 2. Construct temporary bent or install needle beam under sound portion of superstructure. 3. Lift superstructure. 4. Remove damaged or deteriorated section.weld new section into place using full penetration groove welds. 5. Lower member and check for distress. 6. Remove lifting devices. 7. Clean and apply prime coat paint. (8) C Repair Steel Diaphragm/Lateral Bracing Based on need as indicated by bridge inspections or reports of accidental damage. (8) All steel diaphragms, cross frames, lateral bracing, and their connections to beams and girders. (8) Diaphragms are usually composed of a single member such as a channel. In these cases the single member is considered as "one - each item" for measurement purposes. Cross frames are usually composed of at least four elements consisting of upper and lower members and cross members. All of these members together are considered as "one each item" for measurement purposes. Lateral systems may be composed of one or two members, and these may be discontinuous on multi-beam or girder bridges. One element, or two elements fastened together, spanning between connections without a break is considered "one each item" for measurement purposes. (8) Repairing or replacing all or part of the elements in structural steel diaphragms, cross frames or lateral bracing. The work can include, but is not limited to, disconnecting or removing elements by removing bolts or rivets or using oxyacetylene cutting torches; straightening members by the application of heat and mechanical means; prefabricating replacement elements; repairing elements; drilling and reaming holes; erecting repaired or replaced elements by welding or high tensile strength bolting; and preparing surfaces damaged or left bare by the work and applying a prime coat of paint. Cross frames and diaphragms are often connected to beam and girder stiffeners. (8) Equipment Jacks Beams Blocking Cutting Torch Welding Equipment (8) Material Steel Shapes Paint (8)

108 Procedure 1. Modify superstructure to accept jacking loads, if necessary. 2. Construct temporary bent or install needle beam under sound portion of superstructure. 3. Lift superstructure, as necessary. 4. Remove damaged or deteriorated section or member. 5. Weld new section or member into place using full penetration groove welds. 6. Lower member and check for distress 7. Remove lifting devices. 8. Clean and apply prime coat paint. (8)

109 C Repairing Load Bearing Concrete Members C Introduction Reinforced-concrete beams should be kept clean and protected from saltwater, saltwater spray, or water from the deck containing de-icing chemicals. Concrete sealers and coatings protect concrete exposed to saltwater if they are applied to a clean surface before the concrete surface is contaminated. If the concrete surface has already been contaminated, the surface must be blast-cleaned before the sealers are applied; even then, the effectiveness may be reduced because of chlorides penetrating below the surface. (1) Before agency personnel attempt to repair any reinforced-concrete beam that has been damaged, a professionally qualified structural engineer should evaluate the damage, determine the type of repair needed, and evaluate if the agency can perform the repair or if it should be contracted to a firm having capacities not present in the agency. Such repairs include repairing impact damage from over-height vehicles and spalling from corrosion of reinforcing steel. While many factors must be considered when determining the best repair method, two key factors are the location and the severity of the damage. For instance, a small area of damage is not structurally significant in a tension area of a beam if the reinforcing steel is not damaged; thus, it may be sufficient to protect the steel from exposure to elements that cause corrosion. This protection can be provided by placing a surface patch with hand methods or even by coating the exposed reinforcing bars (if appearance is not an issue) or applying shotcrete to the area (if it is cost-effective). (1) If a beam has a large damaged area that will permit a formed repair to be made, make the formed repair because it will likely be a more permanent patch. Generally, placing the aggregate inside the formed area and injecting a grout into the formed aggregate area gives the best results. (1) Structural repairs to beams may require supporting the superstructure during the repair process. Temporary bents or carrier beams designed by a professionally qualified structural engineer will provide the necessary support. If the reinforcing steel is damaged or if the damage extends into a compression area of the beam, however, it may be necessary to jack the dead-load stresses out of the damaged area before repairs are made. C Repair of Spalled Areas of Concrete Beams and Stringers Spall in beams can be dealt with in a similar manner as walls by constructing a form around the damaged area and replacing the lost concrete. Shotcrete is an excellent material to use in this type of repair. The major problem caused by concrete deterioration is the loss of effective reinforcing bar diameter due to corrosion. This is also true of cracks which allow water to penetrate to the reinforcing steel. Due to the criticality of reinforcing bars in beams, it is important to repair or replace any damaged reinforcing bars. There are three methods available to reestablish the reinforcing steel required for proper beam performance: (4) C Conventional repair Spall is repaired primarily by removing the deteriorated concrete and replacing it with new concrete of similar characteristics. The process involves the following: (4)

110 1. Analyze the structure to determine the effect of removing the deteriorated concrete down to sound concrete will have on the structure. Determine the need for and the design of any shoring and bracing required to support the structure during the repair. (4) 2. The concrete must be removed down to sound concrete or to a depth where the patch is at least ¾ inch thick. Sharp edges, at least 1 inch deep, should be formed around the area to be patched to avoid feather-edging the concrete patch. It is also advantageous to make the bottom of the removed concrete areas slightly wider than the surface to form a keying effect with the new concrete patch. If a large surface area is to be overlaid with new concrete, a minimum of ¼ inch should be removed from the surface. The edges of the overlay should be chipped or cut at about 45 degrees to prevent entrapping air under the overlay. Clean sound surfaces are required for any repair operation, and the absolute minimum amount of concrete to be removed is all unsound concrete, including all delaminated areas. (4) 3. The patch area must be cleaned to remove all debris from the concrete removal process. The existing concrete surface and reinforcing steel should then be blast cleaned. The repair is cleaned again and inspected. Any aggregate particles that have been cracked or fractured by scarifying or chipping should be removed to sound concrete. (4) 4. Patches should be reinforced with wire mesh attached either to reinforcing bars or dowels to secure the patch to the old concrete. Loose reinforcing bars should be tied at each intersection point to prevent relative movement of the bars and repaired concrete due to the action of traffic in adjacent lanes during the curing period. If new reinforcement is required, an adequate length to attain a lap splice (30 times the bar diameter) must extend from the existing section. If a proper splice is not possible, holes must be drilled into the existing concrete and dowels or anchors installed. (4) 5. An interface must be established between the existing and new concrete. Options for this include: a. Epoxy bonding. Ensure the surface is clean, dry, and free of oil. Apply the epoxy agent to the prepared surface. b. Grout or slurry. Clean the prepared surface and saturate with water. Remove all freestanding water with a blast of compressed air, and apply a thin coat of grout. 6. After surface preparation, the new concrete must be promptly applied to the repair and finished. (4) 7. The new concrete should be moist cured for a minimum of 7 days to prevent drying shrinkage and to allow proper strength development. This is most easily accomplished by covering the patch with plastic or wet burlap. (4) 8. Shotcrete can also be used to replace concrete in spalled areas. Shotcrete is a mixture of Portland cement, sand, and water shot in place by compressed air. It is best used for thin repair sections (less than 6 inches deep) or large irregular surfaces. Shotcrete requires a proper surface treatment similar to that required for a concrete overlay and no form work is needed to confine the mix. This makes shotcrete useful in the repair of vertical walls, beams, and the

111 underside of decks. This technique requires specialized training and guidance on the use of shotcrete as a repair material. (4) C Conventional Reinforcement This method is primarily used to bridge isolated cracks in the load-bearing portion of the structure for active and dormant cracks. This repair bonds the cracked surfaces together into one monolithic form. Procedures 1. Clean and seal the existing crack with an elastic sealant applied to a thickness of 1/16 to 3/32 inch and extending at least ¾ inch on either side of the crack. 2. Drill ¾-inch holes at 90 degrees to the crack plane, fill the hole and crack plane with epoxy pumped under low pressure (50 to 80 psi), and place a reinforcing bar (No. 4 or No. 5) into the drilled hole with at least an 18-inch development length on each side of the crack. (4) Figure C. 49 Reinforcing bars inserted 90 degrees to the crack plane C Prestressing steel This method can be used to close a crack and/or provide external reinforcing steel to support the beam loading. Procedure 1. Clean the crack and any exposed rebar. 2. Drill holes through the side of the beam (missing existing rebar) for the prestressing anchor at both ends of the beam. 3. Install anchors on both sides and at both ends of the beam by running bolts through prepared holes in the anchors and beam. The anchor should be designed by an engineer and generally consist of a reinforced angle section with holes in the flanges to receive the through bolts and the tension tie. 4. Connect the tension tie to each set of anchors on either side of the beam. 5. Apply tension to the ties using a turnbuckle or torquing nuts. Tension should be applied across both sides of the beam evenly. Increase tension until the crack closes and seal with a flexible seal. This method can also be used in conjunction with a patch to replace deteriorated steel. (4)

112 Figure C. 50 Reinforcement of a crack using stitching C Repair Prestressed Stringer (Post-Tensioning) Prestressed-concrete beams should be protected and maintained just like other reinforced-concrete beams. However, the consequences of poor maintenance can be more serious in prestressed-concrete because the prestressing strands are designed to keep sufficient pressure on the beam so the concrete never experiences tension forces even under the expected live load. (1) Prestressed members have thinner sections than conventional reinforced concrete and are more susceptible to deterioration if cracks in the concrete allow any contaminants to generate corrosion of the steel strands. Since the tension is high in the tendons and the concrete is squeezed together, the loss of a significant amount of concrete can cause the remaining cross section of the concrete to be overstressed and crushed to failure. A single tendon breaking because of an impact loading on the beam or because of corrosion reducing the tendon strength can create a minor explosion within the beam, and if several steel tendons snap, a bridge can fail suddenly and catastrophically. (1) Special procedures are required to repair a prestressed-concrete beam and restore the original dynamic state of stress that gives the beam its high load-carrying capacity. If a significant amount of concrete is to be replaced, the compressive forces must be removed from the concrete beam near the damaged area by applying a calibrated load on the bridge while the new concrete is placed and cured to reach its design strength. A professionally qualified structural engineer should design and review this process, determining the load needed and the proper placement of the load to create the desired stress effect in the beam. (1) Tension must be put back into any broken tendons as part of the repair process Equipment Concrete Mixer Post-tensioning Jacks Access Equip (8)

113 Material Concrete Epoxy bonding material Post tensioning ducts Tendons (8) Procedure 1. Drill 1-1/2 in. diameter holes through the web as shown to accommodate reinforcing steel to tie the new concrete together. These reinforcing bars are to be placed and grouted into the holes. Care must be exercised to avoid drilling through tendons or reinforcing bars. 2. Roughen and clean the surface of the concrete beams where the new concrete is to be bonded. 3. Install the post-tensioning ducts, reinforcing steel and the forming for the new concrete. 4. Cast the contact surfaces with an epoxy resin and place the new concrete while the epoxy is still tacky. 5. After the concrete has attained design strength, tension the strands to the specified load. The strands should be tensioned in a sequence to balance the load on each side of the flange. 6. Fill the post-tensioning ducts with grout. (8) Figure C

114 Figure C. 52 Sections showing damaged area (A A) and added tendons to strengthen the beam (B B) C Repair or Replacement of Reinforced or Prestressed Concrete Diaphragm All concrete diaphragms framed into reinforced concrete or prestressed concrete beams or girders; areas of the deck directly adjacent to concrete diaphragms requiring repair or replacement; areas of reinforced concrete at prestressed concrete beams or girders at and adjacent to diaphragms requiring repair or replacement. (8) Repairing or replacing concrete diaphragms framed into reinforced concrete or prestressed concrete beams or girders. The work can include, but is not limited to, removing damaged or deteriorated concrete and reinforcing steel; drilling, installing adhesive anchors or grouted dowels or threaded inserts; constructing false work or installing temporary hang-ers to support forms; constructing forms; installing reinforcing bars; and placing concrete. (8) Equipment Air Hammer Concrete Drill (8) Material Steel Reinforcemt Concrete Threaded Insert Adhesive Anchors or Dowel & Grout (8) Procedure 1. Remove damaged concrete using 15 lb. hammer. 2. Remove any damaged reinforcing steel

115 3. If remaining steel reinforcement is too short (less than 18' embedded), adhesive anchors threaded inserts or grouted dowels must be used. 4. Drill holes appropriate for either adhesive anchors, threaded inserts or dowels and grout. 5. Install reinforcing steel. 6. Construct form work. Form work must be supported either by false work or temporary hangers. 7. Place concrete. If possible, a one and one half inch diameter vent hole vertically through the deck will facilitate concrete placement. 8. Remove formwork. (8) C Repair of Reinforced or Prestressed Concrete Members Other Than Stringers or Diaphragms All reinforced concrete or prestressed concrete superstructure members such as girders or floor beams, which are not included in the definitions of stringers or diaphragms; areas of the deck directly adjacent to such members; and connections of such members to stringers or diaphragms. (8) Repairing or replacing reinforced concrete or prestressed concrete superstructure members that are neither stringers nor diaphragms. The work can include, but is not limited to, removing damaged or deteriorated concrete and reinforcing steel; drilling and installing adhesive anchors, grouted dowels or threaded inserts; constructing false work; constructing forms; installing reinforcing steel; and placing concrete. Equipment Air Hammer Concrete Drill (8) Material Steel Reinforcement Concrete Threaded Insert Adhesive Anchors or Dowels & Grout (8) Procedure 1. Remove damaged concrete using a 15 lb. hammer. 2. Remove any damaged reinforcing steel. 3. If remaining steel reinforcement is too short, laps cannot be used. Therefore either threaded inserts or grouted dowels must be used. 4. Drill holes, as appropriate, for the adhesive anchors, threaded inserts or dowels and grout. 5. Form work support must be provided either by false work or temporary hangers. 6. Install reinforcing steel. 7. Construct Form work. Brace Form work. 8. Place concrete. 9. Remove Form work. (8)

116 C Truss Repair C Introduction Truss bridges are usually made of steel, although some old trusses constructed of wrought iron still exist. Generally, repair consists of replacing a damaged member or of strengthening a weakened member by adding steel plates to it. Welding should be avoided if at all possible in repairing older trusses since the steel typically has a high carbon content. A professionally qualified structural engineer should make an assessment of the appropriate repair process to be applied to a truss bridge, especially since the methods used to support the structure may be much different for repair of a member carrying compression loads than for one carrying a tensile force. (1) All steel trusses are susceptible to damage from rust and corrosion. In most truss designs, the main load-carrying members cannot suffer a substantial loss of crosssectional area without beginning to lose capacity to withstand design stress levels. Through trusses and pony trusses are generally narrow and especially susceptible to damage from vehicle collisions because the exposed truss members are close to the traveled roadway. Portal and sway bracing of through trusses is also susceptible to collision damage from over-height loads. The condition of connecting pins is critical in maintaining the structural integrity of a truss with pin-connected eye-bars. Since all loads pass through the pin, failure of the pin can cause a complete structural failure of the entire span. A regular, thorough cleaning and spot-painting program is necessary to prevent rust and corrosion damage in all types of truss bridges. Cleaning of pinconnected joints is a critical maintenance activity in pin-connected trusses to ensure that the joints are free to move as the loads are transferred across the bridge. Repair procedures commonly applied to truss bridges to correct deficiencies are as follows: (1) If truss members have been damaged by rust or corrosion and a structural engineering analysis indicates the member is overstressed for its reduced cross section, plates are typically added to the member to compensate for the lost section area. Truss members that have impact damage from collisions may be temporarily repaired using a strut to reinforce damaged members carrying compression loads and using cables with turnbuckles to reinforce damaged members carrying tension loads. If a collision impact has fractured a member, the member usually must be partially replaced and perhaps the entire truss member will have to be replaced. A fractured eye-bar of a pin-connected truss can also be temporarily repaired with a cable to accept part of the stress. However, permanent repair will require that the fractured member be replaced. (1) Damage from collision impacts to truss bridges can often be reduced by upgrading the bridge railing to provide structural protection to the truss. Sometimes it is possible for bridge design engineers to develop a revised network of overhead lateral bracing to increase overhead clearance if a truss is frequently being hit by over-height loads. Some agencies have also found it helpful to install overhead devices that warn truck drivers that their load will not clear the truss overhead bracing. (1)

117 C Replacement of a Vertical Tension Member Replacement of damaged or deteriorated vertical tension member on trusses having riveted or bolted connections. This repair procedure is limited to tension members on riveted or bolted truss connections. (10) Equipment Cable Turnbuckle Cable Clamps (8) Material WF Beam Blocking Paints (8) Procedure 1. Check with the Office of Bridges and Structures for the design of new vertical section, connections and cables and for removal procedure for existing member. In general, new members will be equal to or greater than the inplace member. 2. Restrict traffic to one lane on the opposite side of the bridge or detour traffic if possible. 3. Install the wood blocking and wide flange support beam (chord to chord) as shown in Figure C. 53 Section A-A. 4. Install a cable having the capacity to carry the maximum load in the vertical member being repaired, See Figure C. 53. Make sure that the cable clears the existing structural members. 5. Tighten the cable turnbuckle to remove the dead load tensile force in the member being replaced. 6. If the member to be replaced is composed of angles, as shown in Section C-C, Figure C. 53, it can be repaired by first removing and replacing two of the angles, then removing and replacing the other two angles. The two angles that are removed first should be the weaker ones as determined by the existing condition of the vertical member. If the member to be replaced is similar to that shown in Section B-B, Figure C. 53, first one channel is removed and replaced, then the other. If the entire member can be safely removed, it can be replaced with other sections of equal strength. High strength bolts are used for connecting the new vertical members. 7. Install the batten plates or lacing bars at the required intervals along the vertical. Tighten the high strength bolts at all connections 8. Remove cable slings and other temporary components and restore the bridge to normal traffic conditions. 9. Paint new members and areas where cables have damaged paint on existing members. (10)

118 Figure C. 53 Vertical Tension Member Replacement for Riveted or Bolted Connections C Repairing Diagonal Tension Members Diagonal tension members may be damaged by corrosion, overload, or impacts from oversized vehicles. Damaged diagonal tension members consisting of two eye-bars can be replaced by using rods with U-bolt end connections. With no traffic on the structure, one of the eye-bars can usually be replaced at a time. (1) (10) These procedures are for replacement of damaged or deteriorated diagonal tension members on trusses having riveted, bolted or pinned end connections and are limited

119 to tension members where one half of the member can be removed and replaced at a time. This operation requires great care and sound judgement. (10) Equipment Cutting Roch (8) Material Wood Blocking Cables Bolts & Nuts Replacement Member Paint (8) Procedure 1. Contact the Office of Bridges and Structures for the existing plan and design of new diagonal section, connections and cables which must be equal to or greater than inplace members. 2. Restrict traffic to one lane on the opposite side of the bridge, or detour traffic if possible. 3. Cut and install the necessary wood blocking as shown in Figure C Install cables having the capacity to carry the full dead load in the diagonal plus live load resulting from the restricted traffic. Cables must clear the existing structure to be effective. 5. Tighten the cable system with a turnbuckle. 6. If the member to be replaced is composed of angles, as shown in Section A-A, Figure C. 54 it should be repaired by first removing and replacing two of the angles; then removing and replacing the other two angles. The two angles that are removed first should be the weaker ones as determined by the existing condition of the diagonal member. If the member to be replaced is similar to that shown in Section B-B, Figure C. 54, one channel is removed first and replaced, then the other. High strength bolts are used in connecting the new diagonal members. (See Figure C. 55 for suggested connection of pinned end diagonal.) 7. Install the batten plates or lacing bars at the required intervals along the diagonal. Tighten the high strength bolts at all connections. 8. Remove cable slings and other temporary components and restore the bridge to normal traffic conditions. 9. Paint new members and areas damaged on existing members. (10)

120 Figure C. 54 Truss Diagonal Replacement for Pinned End Connections

121 Figure C. 55 Truss Diagonal Replacement for Pinned End Connections C Replacing Vertical Compression Members The difference between replacing a compression member and replacing a tension member is that a heavier, more expensive temporary support system is needed for the compression member. (1) The temporary support system must be capable of supporting the compression load while the member is removed and replaced. Therefore, each member that makes up the temporary support system will consist of a large, column-like section. To provide room for removing the old compression member, the temporary support must be framed around the old member. It is not mandatory that the temporary support be more than one column; however, since the temporary support is offset, it must be able to resist the unbalanced load that is created when the old member is removed. As the temporary support is installed, the load on the damaged member must be relieved by jacking. The temporary support is designed to support each (and all) jack(s). (1) Equipment Jack Cutting Torch Lifting Equip (8) Material 12"x12" tempoary support member Jacking Blocks Replacement Member Paint (8) Procedure 1. Jack the temporary support until the designated load is reached. Place blocks and wedges that could hold the temporary support in position in the event of jack failure

122 2. Remove rivets or bolts in gusset plates at bottom chord and top chord if entire member is to be replaced. If only a portion of a member is to be replaced, remove rivets or bolts in splice, if present, or cut member in preparation for new splice. 3. If a new splice is to be added, drill holes to template from holes in new member. 4. Install new member. Tighten the high strength bolts at all connections. 5. Remove any temporary blocks or wedges, unload jack, and remove jack and entire jack support system. 6. Paint new member. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C. 56 C Straightening a Steel Truss Member A truss member has been damaged but not cracked by a vehicle impact. The load is removed from the member to prevent stretching or buckling of the heated steel. Yokes are installed to accomplish this. The yokes are designed to act as either compression or tension members. (10) (1) Heat straightening methods apply only to A 7 and A36 steels: therefore, plans or Structural Metals Unit must be consulted to determine type of steel. (10)

123 Procedure 1. Exclude traffic from the immediate area of damage. 2. Identify whether the member is in compression or tension or both. 3. Tighten the clamps of a yoke (see Figure C. 57 for tension member yoke and Figure C. 58 for compression member yoke) down around the damaged member. Use compression type yoke when member is subjected to compression and tension stresses. 4. On tension members only, progressively tighten the threaded rods to remove the tension stress in the damaged member. On compression members, simultaneously apply jacking forces parallel to the member until the compression stress is relieved in the damaged member. 5. By using an oxyacetylene torch, apply heat to the member to a dull red color (do not exceed 650 C). a. Apply heat first to the bottom point of the "V". b. Work slowly back and forth and progressively outward.. 6. Hammer peen the elongated side of the bent member. Although this operation lowers the yield stress of the strain-hardened material, it does help eliminate high residual tresses. 7. During cooling process of heated area, the shrinking effect tends to return the bent portion to its original shape. 8. This process can be repeated after steel cools down if the first attempt at straightening is not adequate. 9. Remove yoke. 10. Paint exposed areas of steel. (10) Figure C. 57 Yoke for Restoring Tension Members by Upsetting Heated Area

124 Figure C. 58 Yoke for Restoring Compression Members by Upsetting Heated Area Figure C. 59 Heat Straightening of Bent Areas in Steel Members Figure C. 60 Heat Patterns for Bending Structural Shapes

125 Figure C. 61 Sequences and Sizes of Heating Patterns for Flame Straightening C Repair of Damaged Lower Chord Members If the damage is localized, such as a transverse crack in one of two channels that make up the bottom chord of a truss, a professionally qualified structural engineer can design a splice as a repair solution. Splice plates have been successfully attached using welds, but fatigue problems may result from welds where the structure experiences a high traffic volume. A bolted connection for the splice is preferable. Details of this procedure should be furnished by the District Bridge Office. The procedure should only be accomplished by qualified personnel. (8) This repair technique can be used on tension or compression members which have one unit of a multi-unit member damaged. Some temporary lateral bracing may be required during the repairs. (10) Equipment Cold Chisel Power Drill (8) Material Side Splice Plates Bottom Plate Bolts & Nuts Paint (8) Procedure 1. Contact the Office of Bridges and Structures for design of splice and tie plates and bolted connections which must be equal to or greater than inplace members. 2. Restrict traffic to one lane on the opposite side of the bridge, or detour traffic if possible

126 3. Drill hole at end of crack (if cracked) See Figure C. 35 through Figure C. 37. Remove any rivet heads which will interfere with the splice plate if the repair is near a connection. Bolt splice plate to the damaged member as shown in Figure C. 62. Splice plates should not be welded. 4. If necessary, remove old tie plates (or lacing bars) from channels or angles in the area of the deterioration or damage to allow placement of the new bottom tie plate. 5. Bolt the bottom tie plate to the member as indicated in Figure C Remove temporary components used and restore the bridge to normal traffic conditions. 7. Paint as necessary to protect members from corrosion. (10) Figure C

127 C Tighten or Shorten Eye-bar and Rod Truss Tension Members Using Flame Shortening Based on need as indicated by bridge inspections and the observation of tension members during the passage of live loads. Special traffic controls for both loadings and speed are required during the work of flame shortening. (8) All eye-bar and rod truss tension members. (8) Tightening rod-turn buckle type tension members by adjusting turnbuckles, and flame shortening eye-bar type tension members by the application of controlled heat and mechanical force, to equalize stresses between tension members of two trusses or elements of single tension members. The work can include, but is not limited to, turning existing turnbuckles; removing paint; installing clamps; applying controlled heat using oxy-acetylene heating torches; applying mechanical force using clamps; measuring the increment of shortening; measuring the frequency of oscillation of paired members to insure that they are essentially equal; and preparing surfaces which have been damaged or left bare by the work, and applying a prime coat of paint. (8) Procedure 1. Remove paint from the eye-bar in the area to be heated. Attach the upsetting clamp while supporting inclined eye-bars as necessary to remove sags. 2. Restrict traffic as necessary to control live loads on the span. 3. Heat the eye-bar to the proper temperature and shorten the bar by upsetting it with force applied by turning the screws of the upsetting clamp assembly. 4. Water quench the bar after it has sufficiently air cooled. 5. Determine the proper tension in the bar by meas-uring the vibration frequency. 6. Restore traffic on completion of the procedure. 7. Repaint as necessary. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) C Strengthening Bottom Chord by Post-Tensioning Based on need as indicated by bridge inspections or reports of accidental damage. Special traffic controls may be required when accidental damage impairs the structural capacity of the truss and during repair or replacement of members. (8) All truss members upper and lower chords, diagonals, verticals, and end posts; and their connections to other elements of a truss bridge such as floor beams, lateral bracing, and bearings. (8) Strengthening a truss member by adding parts such as angles or plates, or repairing a truss member by splicing existing elements and/or replacing parts, or completely replacing an entire member. The work can include, but is not limited to, providing temporary supports and jacking or other means of unloading truss members; removing parts of truss members or entire members by removing bolts or rivets or using oxyacetylene cutting torches; prefabricating replacement elements or entire members; grinding to provide the required finish or tolerances on steel surfaces; drilling and reaming holes; erecting repaired or replaced members or elements by welding or high tensile strength bolting; and preparing surfaces damaged or left bare by the work, and applying a prime coat of paint. (8) Equipment

128 No special equip required (8) Material Posts (Braces) Cables Turnbuckles Paint (8) Procedure 1. Position and install anchor connections. 2. Position and install posts. 3. String cable with turnbuckles. 4. Tension cables to desired force and permanently secure turnbuckle. 5. Clean and paint posts and turn buckles (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C. 63 C Strengthening Top Chord Member Equipment No special equip required (8) Material New Braces High Strength Bolts Paint (8)

129 Procedure 1. Fabricate braces to proper length and drill holes in them. 2. Restrict traffic, as necessary, to provide work space. 3. Drill holes in chord and lower connection to match holes in brace. 4. Attach braces with high strength bolts. 5. Clean and paint new members. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C. 64 Strengthening of Compression Member C Repair of a Floor Beam Damage or deterioration has occurred on floor beams and/or its connections to the stringers. This repair procedure to be used on maximum movements of 20 mm. Procedure 1. Place timber mudsills, etc. on ground and jack deck up to relieve load on the floor beam and stringer connections. 2. Drill 25 mm diameter holes in existing floor beam and new W Beam at about 1 m centers, taking care to match the horizontal and vertical distances (to align the holes and bolting system). 3. Place 19 mm (3/4") diameter rods or bolts through the existing floor beam and then place 25 mm diameter pipe sleeves on the rods or bolts. 4. Place a new wide flange beam on the concrete seat and secure the top of the wide flange beam to the bottom of the existing floor beam. 5. Reinforce the concrete seat with C 310 or C 380 channels by drilling horizontal holes in the seat (at about 500 mm centers) for 16 mm diameter bolt anchors. Bolt the channels down tight to the concrete seat. 6. Place shims between the new wide flange beam and stringers and lower the deck down on to the new wide flange beam system. 7. Remove the jacking system and mudsill. (10)

130 Figure C. 65 Repair of Truss Floor Beam C Strengthen Entire Bridge Cable Sling System Equipment Backhoe (8) Material Concrete Anchors Cables Attachment Assemblies Turnbuckles (8) Procedure 1. Install anchorage devices adjacent to each abutment. 2. Suspend cables across channel each side or truss. 3. Attach cables to anchorage devices and to beams brackets, or other devices on the span. 4. Adjust turnbuckles to tighten cable. (8) Details of this procedure should be furnished by the Bridge Engineer and procedure should only be accomplished by qualified personnel. Figure C

131 C Strengthen Entire Bridge Cable-Stayed Additional Support System Equipment Backhoe Crane (8) Material Concrete (for footing) Tower Cables Attachment Assemblies Turnbuckles Paint (8) Procedure 1. Excavate and prepare foundation for tower. 2. Erect tower. 3. Install cable attachment to the bridge. 4. Attach cables to bridge attachments and the tower. 5. Clean and paint tower. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel.. (8) Figure C. 67 C Strengthen Entire Bridge Shifting Supports Equipment Backhoe Crane (8) Material Concrete Tower Bearings Paint (8) Procedure 1. Excavate and prepare foundation. 2. Erect tower. 3. Modify existing bridge members, as required

132 4. Install bearing. 5. Paint bearing. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C. 68 Added Support C Strengthen Entire Bridge Addition of Support Equipment Backhoe Crane (8) Materials Concrete Tower Bearings Paint (8) Procedure 1. Excavate and prepare foundation. 2. Erect tower. 3. Modify existing bridge members, as required. 4. Install bearing. 5. Paint bearing. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C

133 C Strengthen Entire Bridge Method of Subdivision Equipment Drill Reamer (8) Material H.S. Bolts New members Paint (8) Procedure 1. Add connections for new members. 2. Add new members. 3. Clean and paint new members. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. (8) Figure C. 70 C Strengthen Truss Connections and Braces Equipment Cold Chisel Welding Equip Lifting Equip Cable (8) Material New Assemblies Paint (8) Procedure 1. Relieve load, as appropriate. 2. Disconnect members, if necessary, after relieving the load. Observe any precautions regarding leaving one piece of a two element member in place while repair is affected. 3. Clean and prepare surfaces for welding or anti-corrosion treatment. Cleaning for welding can often be at least partially completed in advance. 4. Position and align parts making use of clamps and pins, as applicable. 5. Weld the connections or fasten as otherwise designed ensuring at least the minimum weld is attained. 6. Clean and inspect welds and apply protective coating to the area, as required. 7. Apply load to the repair. 8. Remove any lifting or dead load supporting equipment. (8) Details of this procedure should be furnished by the Bridge Engineer and the procedure should only be accomplished by qualified personnel. Welding details for this repair should be furnished by the Bridge Engineer and the welding should

134 be accomplished by personnel certified for the type and position of the weld required. (8) C End Vertical Figure C. 71 End Vertical C Eyebar at Pin-Alternate 1 Figure C. 72 Eyebar at Pin-Alternate

135 C Eyebar at Pin-Alternate 2 Figure C. 73 Eyebar at Pin-Alternate 2 C Pin Plate

136 Figure C. 74 Pin Plate

137 C Lateral Connection Figure C. 75 Lateral Connection C Lower Lateral Figure C. 76 Lower Lateral C Vertical Channel at Kneebrace Connection

138 Figure C. 77 Vertical Channel at Kneebrace Connection C Increasing Vertical Clearance by Modifying the Portal Bracing On many older through trusses, vertical clearance is restricted as allowed by modern transportation regulations. The clearance is controlled by the portal brace connected to the top chord, or the end post at the end of the span, or both. The primary purpose of the portal brace is to support the truss against lateral wind loads; however, it may have been designed also to provide support against buckling in the end post. The portal bracing can be modified to increase vertical clearance by replacing it with a shorter depth truss pattern bracing that has an equivalent or greater strength to resist expected wind loads. Thus, it is important that changes to the portal bracing be designed by a professionally qualified structural engineer, and the load-bearing capacity of the end post needs to be checked since the unsupported length may be changed. (1) Equipment Cutting Torch Power Drill Access Equip (8) Material New Members HS Bolts & Nuts

139 Paint (8) Procedure Technique A Remove knee braces Technique B Remove lower horizontal member and cut diagonals to new length. Replace horizontal member in new position and add no diagonals. Technique C Remove all portal bracing and install replacement members, which must be fabricated to fit between end posts. (8) The dimensions, locations, and installation or removal procedure for components shall be provided by Bridge Engineer. Welding details for this repair should be furnished by thebridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) Figure C. 78 Examples of portal modifications

140 C Repair of Timber Members C Introduction Repair methods for wood and timber structures are generally directed at correcting one or more of the following problem areas: fungi and/or insect attack, deterioration, abrasion, and overload. The most common repairs for timber structures are retrofitting timber connections, removing the damaged portion of the timber member and splicing in a new timber, and removing the entire member and replacing it with a new member. Common rules for timber repair are: (4) a. There should be at least 1/8-inch clearances between timbers to allow the timber to dry properly. b. When native logs are used for construction, all bark should be removed to reduce moisture penetration into the logs. c. Green or wet timber shrinks considerably when seasoned. Repeated wetting and drying also causes dimension changes as great as 5 to 10 percent in the direction perpendicular to the growth rings. Frequent renailing and tightening of bolts is necessary. d. Care should be taken when using new and salvaged wood together to carry loads because of a difference in the sag and shrinkage of the members. The repair should avoid using new and old stringers in the same panel. e. Wood shims or wedges should be made from heart cypress, redwood, douglas fir, or of the same material as the member. f. Replacement members must have the same dimensions as the existing member accounting for shrinkage. g. Always treat drill holes and cut ends, to prevent water or insect damage. (4) C Temporary Repair of a Deteriorated Timber Beam Any crack in a timber bridge beam (stringer) reduces its capacity to carry loads and therefore may require immediate repair or replacement before traffic is allowed to use the bridge again. Timber beams with a longitudinal crack can be repaired by placing steel plates on the top and bottom of the beam and clamping the plates together with bolts that extend the full depth of the beam. (1) Generally, replacing a decayed or damaged timber beam is the most cost-effective maintenance practice. In some cases, a temporary repair can be made by turning stringers with small damaged areas (e.g., around the planking spikes), but in many cases this repair will be as costly in time and effort as replacing the stringer. Furthermore, not replacing the stringer leaves a weakened structural member with a short service life until it must be replaced. (1) In many cases, it is easier to replace a damaged timber beam if the deck is removed, but if the deck is heavily spiked to all of the beams and only one beam is damaged, this may not be practical. To deal with the situation where it is not practical to remove the deck, a new beam is installed next to the existing damaged beam (or perhaps a new beam on each side of the old beam). The new beam can be trimmed at an angle on one end, providing space to insert enough of the trimmed end between the pier cap and the underside of the bridge deck so that the new beam can be rotated up against

141 the deck and slid into place over the other pier cap. (If a new beam is placed on each side of the existing beam, it may be better to trim the opposite ends of each new beam.) After the new beam is in position over both pier caps, it should be jacked tightly up against the deck and shimmed with hardwood or metal shims between the beam and pier cap. (The material trimmed off the beam end can be used to make shims.) The deck is then spiked to the new beam (or beams). (1) Figure C. 79 Splicing Augmentation Figure C. 80 Scabbing Augmentation C Repair of a Split Stinger Timber stringers, cross bracing attached to stringers being repaired or replaced, and fasteners to decks. (8) Repairing or replacing timber stringers. The work can include, but is not limited to, providing temporary supports for jacking; jacking stringers and/or portions of the deck; removing fasteners between stringers and the deck and cross bracing; removing existing stringers; fabricating and installing new stringers; treating cuts and holes with wood preservative; replacing existing cross bracing, if necessary, and fastening cross bracing to stringers; and fastening new stringers to the deck. The work can also include all work necessary for installing sister beams which does not involve removing existing stringers. Equipment Saw 15 lb hammer Concrete/Asphalt Saw (8) Material Prefabricated Straps Concrete

142 Plates with holes Draw up bolts with Nuts and Washers Bituminous Patching (8) Procedure 1. Use template to locate holes on cap and scab. 2. Drill holes and treat holes. 3. Insert rings in cap. 4. Install scab. (8) Figure C. 81 Repair of Cracked or Split Stringers C Repair of Decayed Stinger Ends Equipment Power Drill (8) Material Scabs Bolts Rings OG Washers Wood Preservative (8) Procedure 1. Use a template to locate holes on cap and scab. 2. Drill holes for draw-up bolts and treat. 3. Insert rings in the cap. 4. Install scab. 5. Install plates and tighten bolts. (8)

143 Figure C. 82 C Repair/Replace Timber Stringer From Under the Deck A timber stringer has deteriorated and a new stringer must be added to support the deck. (10) Equipment No Special Equipment Required (8) Material Replacement Stringer Wood Preservative Crossbracing Temporary Bent (8) Procedure 1. Place two jacks on each cap in adjoining bays next to deteriorated stringer. Try to place jacks at or near piles for load transfer. 2. Use steel plates under deck and jack to protect members. 3. Remove traffic from jacking area if possible. 4. Jack up the deck until the inplace stringers clears cap by 6 to 15 mm. 5. Cut wedge out of one end of new stringer and bevel comers on other end. Place crown of new stringer to provide bearing on decking timbers. 6. Place wedged end of stringer on cap far enough to allow opposite end to clear other cap. 7. Place a come-along cable or chain around cap at beveled end of stringer and attach to wedged end of stringer. 8. Pull stringer with come-along to final position. 9. Nail cut wedge back on to wedged end of stringer. 10. Remove jacks and come-alongs. 11. Nail or bolt decking to new stringer. (10)

144 Figure C. 83 New Stringer Figure C. 84 Typical Jacking Arrangement Figure C. 85 Erection Scheme C Repair/Replace Timber Stringer From Above the Deck Equipment No Special Equipment Required (8) Material Replacement Stringer Cross Bracing Decking (8) Procedure 1. Remove cross bracing between stringers. 2. Cut deck along center lines of stringers adjacent to stringer to be removed. 3. Remove stringer and continuous deck

145 4. Install new stringer. 5. Replace deck and nail decking in the same manner as existing. 6. Fasten cross bracing to new stringers in the same manner as existing. (8) C Repair of Timber Connections The typical timber connection relies on some type of hardware to connect timber members. However, with the improvements made in glues and lamination, glues are becoming a viable option that can be used to enhance the connection. They provide a bond between the wood surfaces and prevent moisture penetration into the connection. C Bolts, drift pins, and screws The two most common repairs required for these connections are the replacement of the bolts due to rust or damage and retrofitting the bolt hole in the timber. After removal and inspection of the existing bolt or screw, proceed as follows: (4) 1. No deterioration (provides a snug fit for the bolt). Inject a wood preservative into the hole and replace the bolt. (4) 2. Slight deterioration (loose fit for the bolt). Drill out the hole to a size that provides a good wood surface. (Note: The diameter of the hole should not be increased to the extent that the wood cross section will no longer carry the design load.) Inject a wood preservative. Replace the bolt or screw with a larger size to tit the increased hole diameter. (4) 3. Moderate deterioration (hole provides no bearing on the bolt and boring out the hole would reduce the connections load capacity). Remove the deteriorated wood from around the edge of the hole. Inject a wood preservative, and, if possible, coat with tar or creosote. Attach steel plates with holes corresponding with those in the timber connection across the connection to bridge the damaged area. Place bolts through holes in the plates and tighten. (4) 4. Heavy deterioration (connection is beyond repair). Cut off the damaged portion of the member and splice on a new portion, or replace the members which form the connection. C Wood scabbing Scabbing is used to join members together or splice repaired timber members into existing components. Exterior plywood can be used for light loads. However, in most cases standard sawed timbers are used. The first step in any repair of this nature is to check the scabbing for soundness and replace if required. If the scabbing is in good shape, it can be tightened in various ways: (4) 1. Remove loose nails or screws and replace with larger size. 2. Add nails or screws to the existing scabbing. 3. Drill through the scabbing and member and emplace bolts. (4) C Steel connector plates Connection plates are made of light-gauge galvanized steel plates in which teeth or plugs have been punched. If the plate must be replaced, the wood surface may be too damaged for the teeth of the new plate to provide a shear interface. In this case, wood scabbing can be used to replace the steel plate or a new steel plate can be emplaced using nails to provide the interface. A loose plate can also be tightened and strengthened by adding nails or screws to the plate. (4)

146 C Nails, spikes, and screws These are the most common hardware items used to form wood connections. When these items become loose the only options are to: 1. Replace the nail or screw with a larger one. 2. Drive or screw the connector back in place, and add nails or screws to help carry the load of the loose connector. (4) C Deck connectors Timber decking is connected to steel stringers with floor clips (figure 12-3) or nails driven into the under side of the decking and bent around the top flange of the steel member (figure 12-3). Composite action is achieved between a concrete deck and timber stringers by either castelled dapping, consisting of ½ to ¾-inch cuts in the top of the stringer; castelled dapping in conjunction with nails or spikes partially driven into the top of the stringer; lag bolts at a 45-degree inclination to horizontal; or epoxies. (4) Figure C. 86 Common Deck Connectors

147 C.1.3. Miscellaneous Elements C Expansion Joints C Introduction C Open Joints C Neoprene Joints (Preformed Compression Seals) C Cork Filled Joints C Sliding Plate Joints C Finger Plate Joints C Waterproof Expansion Joints C Neoprene Seals C Flex Type C Strip Seals C Foam Type Sealants C Evazote C Other Joint Problems C Drainage C Replace Scupper Grate C Install Drain/Scupper C Install PVC Deck Drain C Install Metal Drains Through Parapets C Install Deck Drain using Eccentric Reducers C Install Standard Scupper C Repair/Replace Downspouting

148 C.1.3. Miscellaneous Elements These sections cover work all other superstructure elements not discussed previously, namely: Expansion Joints Deck Drainage C Expansion Joints C Introduction This work will include any repairs made to any type of bridge joint whether compression seals, finger joints, sliding plates, etc. (4) Deck joints may be classified into six general types. They are: open joints, neoprene filled joints, cork filled joints, sliding plate joints, finger plate joints and waterproof expansion joints. (10) The maintenance and minor repair of joints is covered in chapter B of this manual. Deterioration around a joint in concrete may require a repair of the concrete around the joint in conjunction with resetting the joint. Some of the specialized joint repairs are as follows: C Open Joints If major reconstruction of these joints is necessary, replacement with waterproof joints should be considered to prevent drainage onto superstructure and substructure. The need for maintenance of these joints is minimal. The protection angles sometimes are loosened and bent by traffic or maintenance of the roadway surface. These are cut off flush with the concrete as a temporary repair. To effect permanent repairs the damaged area is removed. Additional concrete is removed to provide additional space to seat anchorage bolts and the joint is formed and re-cast. This joint may be recast as concrete without the angles. (10) Equipment Air Compressor & Air Hammers Welding Equip. Concrete Mixer (8) Material 1/4"x1" Steel Concrete (8) Procedure 1. Locate portion of expansion that is loose and rattling. 2. On 18-in. centers, lay off 12 in. x 8 in. rectangle immediately adjacent to the dam. 3. Outline area of concrete to be removed with a 1-in. deep concrete saw cut. 4. Remove concrete with air hammer. 5. Cut slot in top flange of dam. 6. Weld Z-strap in slot and to reinforcing steel. 7. Place concrete behind dam. (8)

149 Figure C.87 Removal of Joint Protection Angles Figure C.88 Reconstructed Joint Figure C. 89 Welded Z-Strap Repair C Neoprene Joints (Preformed Compression Seals) Repairs to neoprene joints entail repairing or replacing bent protection angles and reinserting or replacing the neoprene joint filler. All old material and debris should be cleaned from the joint and the joint sandblasted before placing new materials. To facilitate inserting the neoprene filler an adhesive coating should be brushed on the sides of the filler which will serve as a lubricant until it becomes tacky. When replacing neoprene material it should be sized to accommodate the anticipated

150 movement as well as the in-place opening. When preformed neoprene joint material is not available, butyl rod may be installed as a temporary repair. (10) A determination of joint movement should be made before replacing the neoprene joint material. Theoretical joint movements of 6 mm (1/4 ) or less indicate that neoprene material need not be used and cleaning the joint and refilling with cork, bit, felt, or paper rope, and a poured seal is sufficient. See Fig. C.5 for rope or Butyl Rod and flexible sealant alternate, and neoprene alternate. (10) If extensive repairs are required serious consideration should be given to replacing neoprene joints with a waterproof type expansion joint. (10) Preformed compression seals can be installed more efficiently during cooler, but not below freezing, temperatures. Surfaces against which seals are placed must be dry, although concrete surfaces may be "damp-dry". (8) Determine the required elastomeric seal size in accordance with these guidelines: (4) Figure C. 90 Equipment Air Compressor Concrete Mixer (8) Material Preformed Neoprene Compression Seal Lubricant Adhesive (8) Procedure 1. Remove existing compressible joint material from joint. 2. Clean joint of any foreign material using compressed air. 3. Remove and replace any deteriorated concrete. (8) 4. Cut new compressible material to fit the joint. If joint extends beyond deck to curbs or medians, then follow these procedures (see fig. C.4): a. To make an upward turn with the seal, proceed as follows. Drill three ½ inch diameter holes on line in the seal. The holes should be spaced at intervals of 1/3H (H = height of the seal) on lines 2/3H from the bottom of the seal. Cut the lower section of the seal from the bottom, and seal the hole in all three locations. Bend the seal in the desired position and install following normal sealing procedures. (4) b. To make a downward turn with the seal, drill a M-inch hole along the seal at the location of the bend in the seal in a position 2/3H from the bottom of the seal. Cut a wedge from the underside of the seal by making two intersecting angled cuts (45 degrees) from the bottom of the seal to the ½

151 inch hole. Bend the seal down and install using normal sealing procedures. (4) 5. Apply lubricant adhesive to the faces of the joint. 6. Position seal over joint opening, compress and insert into joint while the adhesive is still wet. Install seal within the joint to the required depth of application, usually ¼ to ½ inch below the deck surface. (8) Figure C.91 Up-turns and Down-turns of Compression Seal Figure C.92 C Cork Filled Joints The need for repairs to this joint usually results from the cork material coming loose and falling out of the joint or the joint becoming tight from filling with incompressible materials which enter through a broken seal at the top. A loose or open joint may sometimes be left open without any harmful effects. However, this depends on the location of the joint in relation to the substructures and any traveled roadway underneath. To repair a defective joint it should first be cleaned of old

152 material and debris, sandblasted clean, filled with cork or equal, caulked with paper rope or butyl rod and refilled with a flexible sealant material. (10) Figure C. 93 Figure C. 94 C Sliding Plate Joints Maintenance problems associated with this joint are loose and noisy plates, and insufficient space for the sliding plate. A loose and noisy plate can be corrected by tightening bolts, replacing missing bolts and/or shimming under the plate. When the concrete bearing surface under the sliding plate becomes uneven and causes unfirm bearing because of deterioration or other causes, remove the sliding plate and then remove and replace the deteriorated concrete and finally reinstall the plate using a plug weld or bolt system repair procedure. (10) Insufficient space for the plate to slide in will require spans to be jacked back to their original positions. Where the abutment has tipped, other measures have to be taken to

153 provide the space needed and the Bridge Supervisor should consult with his supervisors before undertaking any corrective action. See Figs. C.8 and C.9. (10) Equipment Welding Equip Concrete Mixer (8) Material 12" Bolt with wedge Washer & Nut 1/4" X 4" Steel Plate Latex Modified Concrete (8) Procedure 1. Burn hole through top flange of expansion dam. 2. Drill 1 & 1/4" hole at a 45 angle through the concrete deck below the burned hole. 3. Score a 6" X 6" area of concrete 1" deep with saw around bottom of hole. Remove concrete to bottom mat of reinforcing steel. 4. Place bolt in position and weld to top flange of dam with a full penetration weld. 5. Place latex modified concrete l/2" thick in bottom of 6" X 6" hole around bolt end. 6. Position 1/4" X 4" X 4" steel plate, add wedge washer and nut, then tighten. 7. Coat removed concrete area with epoxy bonding compound and fill with latex modified concrete. 8. Drill and tap flange close to bolt location, install zerk fitting and pump epoxy. 9. Remove and fill zerk fitting holes with weld material. Grind and smooth welds on top flange. (8) NOTE: Epoxy should fill area around bolt and under expansion dam where bond between dam and concrete has been lost. Several zerk fittings may be required to fill void beneath dam. (8)

154 Figure C.95 Sliding Plate Joint Repair Using Plug Welds

155 Figure C.96 Sliding Plate Joint Repair Using Bolt System C Finger Plate Joints Maintenance of these joints when needed is usually to restore the correct spacing in the joint, grind fingers flush, or replace/tighten loose capscrews (especially in wheel tracks). Otherwise these joints have a low incidence of needed repairs. Additional space can be provided by moving the spans back to their original position. These joints sometimes are the cause of maintenance problems to other parts of the structure because of their open spaces which allow water to drain through to the substructure. This will cause steel joint members and bearing assemblies to rust and concrete to scale and spall. When this water leakage problem becomes severe, steps should be

156 taken to conduct the drainage to a safe point for discharge. This may take the form of a trough under the joints with pipes and down spouts. (10) Equipment Air Compressor and Hammers Welding Equip Concrete Mixer (8) Material Finger Plate Joint Assembly Procedure 1. Remove steel dam and supports as necessary by cutting anchors or dam with cutting torch. 2. Remove unsound concrete by saw cutting and jack hammering. 3. Place forms for concrete and anchor system for dam. 4. Set dam in place. 5. Place and finish concrete. 6. Complete assembly of dam or remove temporary shipping and erection braces as necessary. 7. Place new neoprene compression seal, drainage trough or water collector as necessary. (8) Figure C

157 Figure C.98 C Waterproof Expansion Joints C Neoprene Seals C Flex Type Transflex and Waboflex type joints are bolted down in the original installation. A sealant is applied between the joint seal and concrete base and then the bolts are tightened down to 110 N.m (0.081 kip.ft) torque. A maintenance problem with this joint is loose bolts and loss of bond between joint seal and concrete which is caused by vibrations from heavy wheel load passages. Also, bolt hole plugs often break and disappear. In some instances, torquing the bolts reestablishes a waterproof joint but usually resealing with new sealant is required prior to torquing down the bolts. (10) Figure C

158 Figure C.100 C Strip Seals Strip seal joints consist of steel extrusions and waterproof neoprene gland. Details of two strip seal joints are given in Figs. Figure C.101 and Figure C (10) Equipment Welding Equip. (8) Material Modular Dam Joint or Component (8) Procedure 1. Remove deteriorated sections of gland. Heating the seal may be necessary to melt adhesives. Special tools from the seal manufacturer may facilitate seal removal and replacement. 2. Reanchor or replace as necessary any loose sections of the extrusion by removing and replacing deteriorated concrete and extrusion. 3. Replace gland using adhesive and special tools as recommended by the manufacturer. (8)

159 Figure C

160 Figure C. 102 C Foam Type Sealants C Evazote Evazote is closed cell, low density polyethylene, capable of handling movement of 50 percent compression and 25 percent tension. It can be welded together with heat. Evazote is bonded to steel or concrete with an epoxy adhesive. A maintenance problem occurs when the bond fails between the Evazote and adjacent material. Evazote should then be cut out, the area sandblasted clean, adhesive applied to clean surface, new Evazote placed and heat applied to weld the sections together. Spring is the preferred season to install Evazote because as the temperature rises, the bridge deck will expand causing the joint and material to compress, thereby creating better bond opportunities. Evazote is an ethylvinyl acetate. (10) For bending of the sealant (up-turns and down-turns) see section C and Figure C

161 Figure C. 103 Figure C. 104 C Other Joint Problems Plow Fingers Joints with angles which are skewed between 20 and 45 degrees are susceptible to damage and are hazardous to snow plow blades which drop into the joint. To correct this situation snowplow fingers should be placed across the joint (out of wheel tracks) and secured to the side of the joint facing traffic. A joint which becomes tightly closed can be especially damaging to bridge decks by raising them off of the beams or concrete deck girders causing them to crack and spall at the haunches because of the restricted movement. Therefore, joint openings should be restored as soon as possible. Where the pavement may be pushing against the ends of the bridge, a relief joint should be cut in the pavement at the bridge approaches. (10)

162 C Drainage C Replace Scupper Grate Consideration should be given to replacing damaged or deteriorated scupper grates in early spring in areas where bicycling is common. (8) All existing scuppers between backs of abutment backwalls. (8) Removing existing grates; preparing scuppers for installation of new grates; fabricating replacement grates or obtaining prefabricated grates; and installing replacement scupper grates. (8) Equipment Welding Equip. (8) Material Replacement grate assembly (8) Procedure 1. Prepare replacement grate by fabricating new grate, modifying an existing grate or obtaining a prefabricated grate. 2. Remove existing grate. 3. Repair or modify scupper as necessary for replacement grate. 4. Place grate on scupper. (8) Welding details for this repair should be furnished the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8)

163 Figure C. 105 C Install Drain/Scupper All locations at curbs or parapets selected for installation of a scupper between backs of abutment backwalls. Included in the work area is a sufficient portion of the deck so that the installation can be accomplished. Also included is a sufficient number of the superstructure members so that any connection required by the design of the drain can be attached. Installing grates and down spouting incidental to installation of a new or replacement scupper are included in this activity. (8) Installing scuppers and drains. The work can include, but is not limited to, removing sufficient wearing surface if present, to permit drilling a hole in the deck and shaping the surface to facilitate the flow of drainage water; drilling a hole of the correct size in the concrete deck to accommodate the drain pipe; grouting the pipe into position;

164 connecting the pipe to the concrete or steel superstructure elements; replacing the wearing surface; and placing grate bars if they are not part of the prefabricated scupper. (8) Equipment Concrete Mixer Welding Equip Access Equip (8) Material Drain, Scupper or grate assembly Concrete 6" diameter steel or PVC pipe; joints and clean outs Splash block or riprap (8) Procedure 1. Drill hole or holes through the deck to act as drain or to remove sufficient material to place grate, drain, or scupper assembly. Carefully cut and bend any reinforcing bars encountered to permit placement of the drain or scupper. 2. Place grate, drain or scupper. 3. Recast deck around grate, drain or scupper shaping the deck to facilitate drainage. 4. Attach any down spouting supports to beam as necessary. 5. Install down spouting as necessary. 6. Place riprap or splash blocks under drains or down spouting. (8) 7. Plug any old existing drain holes with epoxy or rapid-set concrete patching material. Welding details for this repair should be furnished by the District Bridge Office and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) C Install PVC Deck Drain Equipment Compressor Pneumatic Drill Concrete Mixer (8) Material 6" diameter PVC schedule 40 pipe No. 6 epoxy coated reinforcing bar Concrete patching material (8) Procedure 1. Drill holes through deck and remove sufficient concrete to set grate of epoxy coated No. 6 reinforcing bar. 2. Set drain pipe and grate bar with epoxy or rapid set concrete patching material. 3. Plug any old existing drain holes with epoxy or rapid-set concrete patching material. 4. Place riprap or splash blocks as required under drains. (8)

165 Figure C. 106 C Install Metal Drains Through Parapets Equipment Concrete Mixer Welding Equip (8)

166 Material C 8x 4.25 aluminum or C 8x 11.5' A36 Procedure 1. Remove existing concrete parapet and deck as required. 2. Cut metal drain section to proper length (typically 2'-3') and butt weld together. 3. Place metal drain in proper position. 4. Place concrete around drain and replace concrete in parapet deck as required. (8) Welding details for this repair should be furnished by the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) Figure C. 107 C Install Deck Drain using Eccentric Reducers Equipment Welding Equip Concrete Mixer Access Equip (8) Material Eccentric reducer assembly with grate 6" diameter standard with steel pipe Splash block or riprap (8) Procedure 1. Drill holes through the deck and remove sufficient material to place the drain assembly. Carefully cut and bend any reinforcing bars encountered to permit placement of the drain. 2. Place drain assembly and weld support to beam web. 3. Recast deck around drain shaping the top of the deck to facilitate drainage. 4. Replace wearing surface around drain as necessary

167 5. Plug any old existing drain holes with epoxy or rapid-set concrete patching material. 6. Place riprap or splash blocks under drains as required. (8) Welding details for this repair should be furnished by the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) Figure C. 108 C Install Standard Scupper Equipment Welding Equip Concrete Mixer Access Equip (8) Material Standard Scupper assembly Concrete 6" diameter standard with steel pipe Pipe supports, straps, hangers Splash block or riprap (8) Procedure 1. Drill holes through the deck and remove sufficient material to place the standard scupper. Carefully cut and bend any reinforcing bars encountered to permit placement of the scupper. 2. Place scupper assembly and weld or bolt sup port to beam web

168 3. Recast deck around scupper. Shape deck to facilitate drainage. 4. Plug any old existing drain holes with epoxy or rapid-set concrete patching material. 5. Install down spouting as necessary. 6. Place riprap or splash blocks under drains as necessary. (8) Welding details for this repair should be furnished by the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) Figure C

169 Figure C. 110 C Repair/Replace Downspouting All down spouting and connections of down spouting to superstructure and substructure elements. The work area also includes sufficient areas of the superstructure and substructure elements to make minor repairs to them when necessary and/or to remove existing down spouting anchorages and install new ones. (8) Repairing or replacing portions or all of bridge down spouting. The work can include, but is not limited to, removing deteriorated or damaged dand anchorages to superstructure or substructure elements; repairing portions of superstructure or substructure elements damaged at the down spouting anchorage points using standard concrete or structural steel repair methods, as appropriate; prefabricating all or portions of the down spouting as required; drilling and installing anchorages to the

170 bridge superstructure and substructure; and installing repaired or replacement down spouting. (8) Equipment Welding Equip Concrete Mixer Access Equip (8) Material 6" diameter standard pipe Anchor fittings Concrete (8) Procedure 1. Remove pipe supports, hangers, drain boxes and pipe sections as necessary. 2. Drill new anchor holes in concrete or steel surfaces. 3. Fasten supports to concrete surfaces with expansion anchor bolts or other approved fastener. Fasten supports to steel surfaces with bolts or by welding. 4. Install new pipe sections and attach to supports and hangers. Welding details for this repair should be furnished by the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position of the weld required. (8) Figure C. 111 Plan showing typical installation of scuppers

171 Figure C. 112 Typical downspouting details for prestressed concrete box bear bridges

172 Figure C

173 C.2 Substructure Related Work C.2.1 C.2.2 C.2.3 Bearings C Maintenance C Sliding Plate Bearing Maintenance C Roller Bearing Maintenance C Rocker Bearing Maintenance C Pin-and-Hanger Bearing Maintenance C Elastomeric Bearing Maintenance C Pot Bearing Maintenance C Bearing Repair C Roller Bearing Repairs C Rocker Bearing Repair for Reducing Expansion C Reset Rocker Bearings C Repair/Rehab other Steel Bearings C Elevating Bearings to Increase Vertical Clearance Bearing Seats C Introduction C Reconstruction of a Bridge Cap C Bridge Seat Repair by Concrete Cap Extension C Pedestal/Seat Reconstruct C Pedestal/Seat Modification to Elevate Bridge Profile Abutments/Wings/Piers C Repair Substructure Cracks C Repair Water Line Deterioration C Repair Surface Deterioration of Abutments C Repairing All or Portions of Concrete or Masonry Abutments C Repairing Abutment Faces by using Jacket Concrete C Abutment Stabilization C Repair to Increase the Load Carrying Capacity of Deteriorated Abutment Walls or Bridge Seats C Repair to Protect Exposed Abutment Footing and/or Piling C Repair of Partially Spalled and Cracked Concrete Abutment and Footings C Install L-Shaped Abutment Jacket to Strengthen Stone Abutments C Repoint Masonry Walls C Repair Backwall C Replace Concrete Wingwalls C Repair Broken or Deteriorated Concrete Wingwalls C Repair of Concrete Wingwall That is Breaking and Tipping Outward on One Side of Abutment C Repair of Concrete Wingwalls That Are Breaking and Tipping Outward on Both Sides of Abutment

174 C Extend Wingwalls with Gabions C Repair to Stabilize Existing Wingwalls with Gabions C Repair to Protect Exposed Abutment Footing and/or Piling C Repairing Spread Footing C Underpin Footing with Concrete or Pumped Grout C Underpin Footing Using Tremie Concrete C Repair Abutment Slopewall C Construct New Abutment Slopewall C Piles, Piers and Bent Repair C Repair Deteriorated Concrete Pile C Pile Replacement C Casting Subfooting to Cap Piles C Repairing Concrete or Masonry Piers C Repair of Tilted Pier and Deck C Repair of Cracked Hammer Head Piers Using Epoxy Grout and Reinforcement C Repair Cracked Hammer Head Piers by Post Tensioning C Repair of Steel Piles Using Channel Splice C Repair Steel H-Pile Bents With Concrete Jacket C Strengthen Existing Cap C Replacing Timber Caps C Repairing Rotated Caps C Repair All or Nearly All Piles in a Timber Bent C Replacing Timber Pile Bent With Steel Columns C Replace Single Pile C Strengthening by Installing Helper Timber Bents C Replace Pile Section C Replace Timber Cross-Bracing C Underwater Repair of Substructures C Engineering the Repair C Control of Work in Waterways C Protecting Underwater Bridge Elements C Pressure Injection of Underwater Cracks C Concrete Repair Underwater C Concrete Removal C Forms C The Mix C Underwater Placement C Bagged Concrete C Prepackaged Aggregate Concrete C Tremie Concrete C Pumped Concrete C Free-Dump Concrete C Hand-Placed Concrete

175 C.2. Substructure Work on substructure elements consists of work on: Bearings Bearing Seats Abutments, Wingwalls, Footing, Slopewalls, Piers, Piles and Pile Caps C.2.1. Bearings C Maintenance C Sliding Plate Bearing Maintenance Sliding plate bearings are plates of similar or dissimilar metal that slide on each other. Early versions were steel on steel, steel on bronze, or bronze on bronze. Refinements that developed later include slightly rounding one bearing surface to reduce frictional binding, inserting a thin sheet of lead or asbestos between the plates, using a graphiteimpregnated bronze plate, and incorporating a pad of elastic material (e.g., polytetrafluoroethylene) with a stainless-steel surface. Corrosion that increases friction is the most common problem with sliding plate bearings. If movement in the bridge exceeds that anticipated in the design, sliding plate bearing problems can also arise. Maintenance of a sliding plate bearing requires jacking the structure, except for cleaning the bearing area, removing debris from the bearing area, and lubricating a bearing that has a grease fitting. If a sliding plate bearing surface is corroded or will not allow movement, the bridge must be jacked to remove the bearing surface for cleaning, lubrication, and repositioning (if needed). Lubricants on the bearing plate surface can include a good waterproof grease, oil, or graphite, or lead sheets can be placed between steel plates, or a bronze plate can slide against a steel plate. If a sliding plate bearing assembly was not designed and constructed to include a grease fitting, consider installing one while the assembly is being maintained so that the plate surfaces can be lubricated without jacking the structure. (1) Figure C. 114 Sliding plates Figure C. 115 Grease fittings on sliding bearings

176 C Roller Bearing Maintenance Roller bearings are devices that incorporate a horizontal roller to permit longitudinal movement of the bridge structure. They range from a simple cylindrical roller to variations of segmented rollers and pinned rockers. In some designs, steel balls have been used with lateral restraints to prevent lateral movement. Many roller bearing devices are enclosed units and therefore difficult to gain access to for maintenance. Some units are housed in a sealed lubricant enclosure. Routine maintenance consists of keeping the bearing area clean and painted. Lubrication is generally limited to keeper links and nesting mechanisms that require disassembly. Figure C. 116 Roller and rocker nests C Rocker Bearing Maintenance Rocker bearings are pedestals with circular bottoms that support a pin. Since the weight of the bridge is transmitted to the rocker through the pin, it is a critical part of the assembly. The pin may become excessively worn or corroded (and then freeze up). The surface of the rocker and bearing plate can be limited in its range of movement by debris and dirt buildup. If the bridge moves beyond the intended design range of the rocker bearing, the rocker can become unstable and fail. Maintenance generally includes keeping the assembly clean, lubricated, and painted. Debris and dirt should be removed from under the rocker, and if such a problem persists, a cover for the rocker assembly should be designed and installed to keep debris and dirt away from the rocker. When pins become worn or corroded, making lack of movement a problem, they should be removed and either replaced or cleaned and lubricated, which requires jacking the bridge. Special pins can be fabricated with grease fittings and installed to permit lubrication without disassembly. (1)

177 Figure C. 117 Rocker bearing Figure C. 118 Detail of typical link C Pin-and-Hanger Bearing Maintenance Pin-and-hanger bearing devices are used where the load is transmitted from the end of one span (i.e, a cantilever span) to another (i.e., a suspended span). Thus, there is not a substructure element directly under the bearing. Most modern designs do not incorporate pin-and-hanger bearings, but many existing steel beam and truss spans have these type of bearings. Because these bearings are located under a deck joint, the pin-and-hanger assembly is particularly susceptible to corrosion. Corrosion tends to cause the assembly to freeze up, preventing movement, which in turn transmits very large forces to the assembly that can result in pin or hanger failure. The pin frequently breaks while resisting torsional forces. Hangers most often fail at either end adjacent to the hole through which the pin is fitted. A serious maintenance difficulty with pinand-hanger bearings is that any corrosion of the pin and its bearing surfaces is not easily detected without disassembling the bearing, which is also generally not feasible because these bearings are not located over substructure elements, so are difficult to gain access to. Many pin-and-hanger installations were not equipped with lubrication fittings, which further complicates maintenance and often contributes to the freeze-up of the bearing. Failure of a pin-and-hanger bearing can lead to catastrophic failure of the bridge; therefore, it is very important to inspect such bearings and watch for any cracking or other stress failure indications. In many cases, redundancy has been added to pin-and-hanger bearings that were not initially designed and constructed to be redundant to prevent a sudden failure of the bridge. However, even with redundancy improvements, bridge failures can still happen if pin-and-hanger bearings are not regularly and carefully inspected in an attempt to identify frozen or damaged assemblies. (1)

178 C Elastomeric Bearing Maintenance Elastomeric bearings incorporate an elastic material, such as neoprene, in either single or multiple pads, with or without steel plates embedded into the laminations, that compress and deform under both longitudinal and rotational movement. This material typically has a long life and is able to withstand repeated deformation cycles. Consequently, maintenance is rarely needed unless the bearing completely fails or gradually works out of position. The bridge must be jacked to replace or reposition the bearing. If the bearing slips out of position on a recurring basis, an abrasive material can be added to the contact surface or a keeper plate can be attached to the bearing seat. (1) Figure C. 119 Elastomeric bearing pad These bearings have been designed to accommodate movements up to 75 mm (about 3 inches) and several degrees of rotation. The bearings may fail because of deterioration of the material, excessive crushing, separation of composite pad laminations, or excessive shear forces. Excessive shear is normally considered to result from longitudinal movement exceeding 25% of the bearing height. Uneven compression and twisting of an elastomeric bearing can also contribute to problems. (1) C Pot Bearing Maintenance A pot bearing is a special adaptation of the elastomeric bearing that incorporates a steel ring to limit deformation of the elastomeric material. The elastomer rests on a stainless-steel plate to reduce friction and to permit sliding. Pot bearings can be damaged by movement or loading that results in uneven compression across the bearing. A hydraulic pot bearing can lose its operational effectiveness if a piston seal leaks or a piston or pot is cracked. Elastomeric pot bearings experience bond failures between the Teflon and the substrate, bond failures between the stainless-steel plate and the sole plate, deterioration of the stainless-steel plate, and cut or deteriorated Teflon. Routine maintenance is normally limited to keeping the bearing area clean and free of debris. When a pot bearing fails or malfunctions, the bridge must be jacked so that the bearing can be removed for repair or replacement. (1)

179 Figure C. 120 Pot Bearing C Bearing Repair C Roller Bearing Repairs When roller bearings stop functioning as designed and intended, they must be removed and refurbished, which in turn requires jacking the end of the span connected to the bearing. Since the nests and mechanisms normally require off-site shop maintenance to be rebuilt, many agencies fabricate spare units so that a complete change out of the roller bearing assembly can be performed in the field to avoid closing a bridge for an extended period of time. (1) The following procedure is for Roller nest bearing assemblies that have accumulated dirt and deteriorated to the point that will hinder bearing movement. This procedure is temporary in nature and is intended for situations where replacement or reconstruction will occur within 5 to 10 years. (10) Procedure 1. Jack up beams and remove roller nests. 2. Sandblast bearing area clean on inplace top and bottom plates. 3. Weld plates together to form new assembly with the same thickness as original roller nest. Top plate surface of new assembly to be finished to 3.2 micrometers or less. 4. Obtain weld procedure from Structural Metals Unit and weld bottom plate of new plate assembly to inplace bed plate. 5. Place grease on top of new plate assembly to reduce friction on sliding surfaces. 6. Uniformly lower the beams back down on the new bearing assemblies. (10)

180 Figure C. 121 Bearing Elevation (With inplace rollers) Figure C. 122 Bearing Elevation (With new bearing plate assembly) Figure C. 123 New Bearing Plate Assembly C Rocker Bearing Repair for Reducing Expansion The following procedure is for when Bottom of rocker bearing is free to slide under little or no load and it misaligns easily. (10) Procedure 1. Jack up the bridge deck to relieve the load on the rocker bearing. 2. Rotate rocker assembly to provide room to work and if necessary block up the rocker assembly to remove the holder pin and rocker assembly. (This step is necessary to clean, lubricate or replace the rocker assembly.) 3. Drill holes and/or arc cut a semi circle for a 25 mm diameter rod as shown in the side elevation view of Figure C. 124 through Figure C

181 4. Weld two 25 mm diameter steel rods about 40 mm long on top of base plate. Anchor rod nut location may need to be revised to obtain wrench and welding clearance. 5. Reposition, or replace rocker assembly and the holder pin (if removed initially). 6. Lower the jack down and check to make sure that there is a slight clearance between the steel rod and rocker assembly. If clearance is not adequate, enlarge semicircular hole to provide clearance. (10) Figure C. 124 Half Front Elevation Figure C. 125 Section A-A Figure C. 126 Detail A C Reset Rocker Bearings Based on need as indicated by bridge inspections. Requirement for resetting often indicates substructure movement. If substructure movement continues, investigation should be scheduled. (8) All expansion bearings at abutments and piers. Small areas of the pedestals/seats at and directly adjacent to masonry plates are also included for making minor repairs, leveling or adjusting the elevation of the contact surfaces, and installing new anchor

182 bolts. Superstructure members at the bearings are included to permit modification or adjustment required as a result of the resetting. (8) Resetting and relocating expansion bearings by adjusting the location of masonry plates on the bottom of bearing assemblies or, alternatively, relocating sole plates on top of bearing assemblies. The work can include, but is not limited to, temporarily modifying the superstructure to accept jacking loads; providing temporary supports for jacking; removing loads from bearings by either jacking from below or using needle beams from above; disassembling bearings; cutting off anchor bolts; preparing concrete contact surfaces for relocation of masonry plates; locating masonry plates so that bearings will be properly positioned for the temperature at time of resetting; drilling holes for and grouting in new anchor bolts and reassembling bearings; or, as an alternative to relocating masonry plates, disconnecting sole plates from superstructure members; modifying superstructure members to accept relocated bearing loads; and reconnecting sole plates to super-structure members so that bearings will be properly positioned for the temperature at time of resetting. (8) Equipment Access. Equip. Jacks (8) Material Epoxy (8) Procedure 1. Jack the bridge to a height required to reset or reposition bearings. A detailed jacking plan shall be developed by the Bridge Engineer based on structure details. Precautions shall be taken to prevent damage to the bridge during the resetting or repositioning of the bearings. 2. Reset rocker bearings so that the total travel it experiences can be divided equally by its median position. A table based on the length of bridge expanding at the bearing shall be developed by the District Bridge Engineer for various temperatures. 3. Bearing areas shall be so reconstructed as necessary that no water accumulates or stands at any point. The bearing surface shall be smooth and level. Fill minor depressions with an accepted low-viscosity epoxy, applied with a squeegee. 4. Remove jacks. (8)

183 Figure C. 127 C Repair/Rehab other Steel Bearings Frozen or misaligned bearings must be repaired or replaced. Good maintenance planning for this process generally includes the following items: (1) Determining the root cause of the bearing problem. Good bridge maintenance needs to address the cause of the bearing failure if it extends beyond the bearing itself. Otherwise, bearing maintenance is treating a symptom and not a cause. Evaluating the existing bearings to determine if repair, replacement in kind, or upgrading to a different type or newer design bearing is needed. Positioning a bearing, when setting or resetting it, so that it is centered at the median temperature for the geographical area in which the bridge is located. (1) All steel bearings, both fixed and expansion, at abutements and piers and pin or pin and link assembliers for cantilever/suspended spans. (8) Repairing or rehabilitating steel bearing assemblies of all types and sizes. The work can include, but is not limited to, temporarily modifying superstructures to accept jacking loads; providing temporary supports for jacking; removing loads from bearings by either jacking from below or using needle beams from above; disassembling bearings; prefabricating replacement parts; repairing, rehabilitating or replacing parts of bearings; reassembling bearings; and painting bearings with a prime coat. The work of lubricating bearings and resetting expansion bearings is included in this activity. When it is performed as part of a repair or rehabilitation, separate reports to activities A743501, Lubricate Bearings, and activity C744502, Expansion Bearings (reset), should not be made. (8)

184 Equipment Crane Jacks Wire Brush (8) Material Temporary Bent or Needle Beam Lubricate Paint (8) Procedure 1. Modify superstructure to accept jacking loads, if necessary. 2. Construct temporary bent or other supports for jack support or install needle beam. 3. Jack superstructure and remove the bearing. 4. Disassemble bearing 5. Install prefabricated replacement parts. 6. Clean, paint and lubricate other parts. 7. Reassemble bearing. 8. Remove jacks or needle beams. (8) C Elevating Bearings to Increase Vertical Clearance As roadway pavements deteriorate and overlays are added, the clearance under bridges commonly decreases. Replacement or repair of overpass bridge bearings is a good opportunity to consider modifying the bridge bearings to raise the vertical clearance under a bridge, if it would improve safety and commodity movement efficiency. (1) Procedure 1. Jack and support the bridge slightly above the new elevation while seat and bearing modifications are made. Jack the spans together to avoid damaging the joints or if the superstructure is continuous. 2. Modify the bearing seats to raise the bearings the required distance. For adequate superstructure support, the seat modification should be designed by a professionally qualified structural engineer. A steel pedestal or a reinforcedconcrete addition are typical methods of modifying the bearing seat. 3. Modify bridge approaches to match the new elevation of the bridge deck. (1)

185 C.2.2. Bridge Seats C Introduction Problems often found in concrete bridge seats include deterioration of concrete and corrosion of the reinforcing steel. Such problems are caused by moisture and contaminants falling through leaking deck joints. A horizontal crack along the face of the pier cap, 75 to 100 mm (about 3 to 4 inches) from the top, normally indicates that the top mat of reinforcing steel has expanded because of corrosion and has forced up the concrete (i.e., delaminated it). (1) When a superstructure moves beyond the space that is provided for it in the bearing assemblies, pressure is created on the anchor bolts. This can be caused by an inadequate design, improper placement of the bearing assemblies, or corrosion of the sliding surfaces, which produces friction. Occasionally, lateral forces from large chunks of debris hitting a bridge during flood flows or high water levels, or an over-height vehicle hitting a beam can also create large forces on the anchor bolts. The pressure from the anchor bolts is then transmitted to the substructure cap, which can damage the bridge seats or cause cracks in other parts of the substructure (such as the columns). (1) No bearing device was provided on some older concrete bridges except for a thin fabric or paper bond breaker. Friction created by the beam or bearing device sliding directly on the bridge seat can cause the edge of the seat to shear if insufficient reinforcing steel exists in this area. (1) Planning for maintenance repair of the substructure should consider the following: Identify the extent of the damage by sounding the concrete and marking the areas of unsound concrete. Make provisions to correct the cause of the damage. Plan to remove vehicular traffic from the bridge during jacking operations. Determine the size, number, and location of jacks that will be required. Ensure that jacking will not damage joints, bearing assemblies, or the area supporting jacks. Define the needed resources, which generally include jacking equipment, form carpentry, concrete sawing or chipping equipment, and any necessary staging. C Reconstruction of a Bridge Cap The substructure cap can be repaired or a new cap cast to offset any settlement that may have occurred at the substructure. Reconstruction of a bridge cap requires raising the superstructure to provide work space as well as to take the load off the bridge cap. (1) 1. Construct a temporary bent for supporting the jacks and blocking if jacking from abutment of pier elements cannot be done. 2. Remove vehicular traffic from the bridge while jacking the superstructure. 3. Lift the jacks in unison to prevent a concentration of stress in one area and possible damage to the superstructure. 4. If the bridge will carry vehicular traffic during repairs, restrict the traffic away from the repair area as much as possible. 5. Saw cut around the concrete to be removed and avoid cutting any reinforcing steel. 6. Remove deteriorated concrete to the horizontal and vertical planes, using pneumatic breakers

186 7. Add new reinforcing steel where it is required. 8. Apply bonding material to the prepared concrete surface that must interface with the new concrete to be placed. 9. Build forms for the new concrete as required and place the new concrete. 10. Service, repair, or replace the bearings as needed. 11. After the new concrete has cured and reached its required strength, remove forms, blocking, jacks, and temporary supports. Recent field trials have successfully applied carbon fiber composite material to repair pier caps (12). (1) C Bridge Seat Repair by Concrete Cap Extension Concrete cap extension. This repair restores adequate bearing for beams that deteriorated or sheared at the point of bearing by anchoring an extension to the existing cap. (4) Procedure 1. Locate and drill 6-inch-deep holes to form a grid in the existing cap and install concrete anchors that will accept a ¾-inch bolt. Place ¾- by 9-inch bolts 4 inches into the concrete anchors. 2. Wire a reinforcing steel (No. 4 bars) grid to the inside head of the anchor bolts. 3. Construct a form around the reinforcing steel grid with a minimum of 4 inches cover around the sides of the bolts and a minimum of 2 inches cover for the face of the extension. 4. Place roofing paper against the bottom of the beam and place Class IV concrete in the form. 5. Remove forms after 3 days. The extension should not carry any load during curing. 6. Repair any damage to the end of the beam. (4) Figure C. 128 Concrete cap extension to increase bearing surfaces C Pedestal/Seat Reconstruct This procedure is performed on bridge seats and/or pedestals at abutments and piers to a maximum depth of approximately 1-1/2 times the length of the anchor bolts and is for reconstructing bearing pedestals and/or bridge seats. (8) The work can include, but is not limited to, temporarily modifying superstructures to accept jacking loads; providing temporary supports for jacking; removing loads from bearings either by jacking from below or by using a needle beam from above;

187 disassembling bearings and/or providing means to support the bearings or portions of the bearings from the superstructure members; removing deteriorated or damaged concrete and reinforcing steel; drilling and grouting or otherwise securing dowels into existing concrete; placing and tying reinforcing steel; constructing forms; installing anchor bolts; placing concrete; preparing contact surfaces of concrete; and replacing bearing assemblies. (8) Equipment Concrete Mixer Air Compressor with Hammer Jacks Access Equip. (8) Material Concrete Epoxy bonding Material Reinforcing Steel (8) Procedure 1. Construct temporary bent for supporting jacks and blocking if jacking from abutment or pier elements cannot be accomplished. 2. Place jacks and lift beam until bearing pressure is completely relieved. 3. Remove deteriorated concrete to horizontal and vertical planes. 4. Add new reinforcing steel where required. 5. Form as required. Apply epoxy bonding compound to prepared surface of sheared beam and cast new concrete. 6. After concrete has reached required strength, remove forming, blocking, jacks and temporary supports. (8) Figure C. 129 Typical Repair of Sheared Concrete Beam Seats C Pedestal/Seat Modification to Elevate Bridge Profile Equipment Staging Equip. Access Equip

188 Material Prefabricated Pedestals Fabric Pads Procedure 1. Prefabricate the pedestals. 2. Jack the bridge to the height required to install the new pedestals. A detailed jacking plan shall be developed by the Bridge Engineer based on structural details. Precautions shall be taken to prevent damage to the bridge during jacking. 3. Remove any temporary blocking, install 1/4 in. preformed fabric pad on the bearing surface, and place the permanent pedestals in position. The fabric pad and bearing surface should be swabbed with red lead paint. 4. Install cross bracing or other type bracing; field weld or bolt as required and make any necessary adjustments; anchor the pedestal to the pier or abutment. 5. Reposition the beam bearing assemblies on top of the pedestals. 6. Lower the span to bear evenly on the pedestal bearings. 7. Complete all field welding and/or make other final adjustments; tighten all anchor bolts. 8. Remove jacking equipment, cribbing etc. 9. Excavate behind the abutment backwalls and wingwalls to a depth sufficient to facilitate the removal of concrete as required to ensure bond to the existing reinforcing steel. 10. Construct back and wingwalls to the new elevation as required. 11. Backfill abutment and wingwalls; reconstruct bridge approaches as required. (8)

189 Figure C

190 C.2.3. Abutments/Wings/Piers C Repair Substructure Cracks A footing may crack transversely because of uneven settlement of the pier or abutment. This crack is often accompanied by a crack continuing up through the pier or abutment. It is advisable to seal the crack, preventing further intrusion of silt, debris, and water that will attack reinforcing steel. If the crack is moving, it should be filled with a flexible material; otherwise, it will open again. If the crack is not moving, it can be bonded back together. Cracks in substructures are generally vertical. Typically, the most effective method of repair is to inject epoxy into the cracks. To get maximum penetration of the epoxy filler, the first injection is made at the bottom of the crack. Starting at the bottom and working up in gradual increments toward the top increases the pressure needed to apply the epoxy and should result in greater crack-filling penetration. Another repair method that prevents moisture from entering the crack is to chisel a V into the opening and fill it with grout. (1) 1. Cut a V-shaped groove at the surface along the crack approximately 50 to 75 mm (2 to 3 inches) in width, using a small pneumatic chisel. 2. Thoroughly flush and blow out the crack, using water and high-pressure air blasts. 3. Secure a retaining form on the face of the footing over the vertical portion of the crack. 4. Wet the surfaces of the crack thoroughly by pouring liberal quantities of water into it. Fill the crack with cement (or epoxy) and fine sand grout in a 1 to 2 mix that runs freely. 5. Clean out the V portion of the surface after the grout has partially set and apply bonding compound or a neat cement base to the surface of the V; then fill the V with a stiff grout mixture. (1) C Repair Water Line Deterioration Deterioration at the water line is unique to abutments or piers in streams or marine environments. A depression or cavity forms in the concrete, extending some distance above and below the average water level. Deterioration at the water line usually occurs on the upstream face or along the sides of the pier. Repair is very similar to any surface deterioration repair, except that it is necessary to control the water flow so the work can be kept dry. (1) Since repair of deterioration at the water line can be time consuming and expensive, maintenance supervisors should have the damage situation evaluated by a professionally qualified structural engineer or materials engineer to determine if this work should be done by maintenance personnel or contracted to a firm with special skill and experience in such repairs. (1) Procedure 1. Dewater the abutment or pier. 2. Chip away all loose concrete in poor condition. 3. Clean the reinforcing steel of scale and loose rust. 4. Clean the surface in all areas where new concrete will be placed

191 5. Chip or roughen the surface of the existing concrete, providing a better bond between the old and the new concrete. 6. Treat the entire area with epoxy or grout before placing the new concrete. 7. Construct a form of adequate strength and place concrete in the form. (1) C Repair Surface Deterioration of Abutments To repair any deteriorated concrete, completely remove all unsound concrete. Clean, sound concrete must be exposed to bond with the new concrete. Air tools are typically the most efficient means of removing the deteriorated concrete. The edge of any area cut out should be undercut enough to allow for deep patches that aid retainment of the new material to the existing concrete. Effective bonding of the new concrete to the old concrete is usually accomplished with a bonding material and is particularly important when deep cracks need to be filled with a large volume of concrete. A grout of neat cement base can be used as an effective bonding agent. Grout can also be used when the form of the concrete is so inaccessible that an epoxy material cannot be effectively applied to the existing concrete surface. The exposed area can be sloshed liberally with grout just before placing the new concrete. Shotcrete may be used to fill the crack after it has been properly prepared. (1) Shotcrete is a concrete mortar pneumatically projected at high velocity onto a surface area. Shotcrete repair is effective for the repair of bridge beams, caps, piers, abutments, wing walls, and decks. Since forms are not generally used for shotcrete, it is particularly effective for an overhead patch on the underside of a deck where a form cannot possibly be used. Shotcrete gives a superior surface bond, provides great strength because of its high density, exhibits low shrinkage, and does not require any formwork; however, it requires lots of space to be applied, demands a high skill level of the application operators, leaves a shoddy appearance, and is costly (especially in small quantities). When shotcrete is used, no bonding agent is necessary if the patch does not exceed a depth of 75 mm (3 inches). For deeper patches, hook anchors are installed in the existing concrete on 300-mm (12-inch) centers, and 50-mm 50-mm (2-inch 2-inch) wire mesh is hooked and wired to the anchors. This anchoring system may be repeated for every 75 mm (3 inches) of shotcrete depth applied. Whenever possible, use form and placing rather than shotcrete. Shotcrete tends to waste cement and requires a much higher worker skill level to obtain satisfactory results. (1) Surface deterioration in reinforced concrete will frequently reach the first layer of reinforcing steel. When this has occurred, the concrete should be removed to a depth of 40 mm (1.5 inches) to 60 mm (2.5 inches) below this layer of reinforcing steel to provide an excellent anchor for the new concrete or shotcrete. If concrete removal is stopped at the surface of the reinforcing steel, a cleavage plane may develop at the interface of the new concrete and the old concrete, reducing the strength of the structure. All rust and other harmful materials should be removed from the exposed reinforcing steel. Where reinforcing steel is exposed, clean both the concrete and the steel by sandblasting the cracks for a good repair. (1) C Repairing All or Portions of Concrete or Masonry Abutments The work can include, but is not limited to, installing sheeting when necessary and excavating material retained by or protecting the abutment; temporarily modifying

192 superstructures to accept jacking loads; providing temporary supports for jacking; removing loads from abutments either by jacking from below or using needle beams from above; removing deteriorated or damaged concrete, reinforcing steel or masonry; drilling and installing dowels; installing reinforcing steel; constructing forms; placing concrete; replacing and pointing masonry elements; pressure grouting masonry; epoxy pressure grouting; and replacing excavated material. (8) Equipment Gradall or Excavator Concrete Mixer Staging, needle beam, jacks or other equip to remove the load Tamper or roller Welding Equip (8) Material Concrete Mixer Reinforcing Steel (8) Procedure 1. Remove backfill or materials protecting or being retained by the abutment to gain access to the repair area. 2. Provide temporary supports for jacking or set up needle beams to remove loads from the abutment as required. 3. Remove loads from the abutment by jacking or using needle beams or removing portions or the entire span as necessary. 4. Remove deteriorated concrete or masonry and additional material as required to establish vertical and horizontal surfaces. 5. Place dowel bars, reinforcing steel and forms. 6. Apply bonding agent, place and cure concrete and remove forms. 7. Reload the abutment by removing jacks or needle beam or replacing the span. 8. Place and compact backfill and rock protection as required. (8) C Repairing Abutment Faces by using Jacket Concrete Concrete in abutments may deteriorate from the effects of water, de-icing chemicals, freeze cracking, or debris impact, any of which can result in portions of the edge or face of the abutment breaking off. Repair is necessary to prevent continued deterioration, especially increased spalling due to moisture reaching the reinforcing steel and causing corrosion. Equipment Air compressor Concrete drilling equipment Concrete Mixer Materials Tie screws (and lag studs) Reinforcing steel-wire mesh Forming material Reinforcing steel Portland cement concrete Epoxy bonding agent

193 Gravel (stone or riprap also). (1) Procedure 1. Establish vehicular traffic control if needed. 2. Remove deteriorated concrete and loosened face surface material by chipping and blast-cleaning. 3. To support the form work, drill and set the tie screws and lag studs. 4. Set reinforcing steel and forms. 5. Apply epoxy bonding agent to the concrete surface just before placing the concrete. 6. Place the cement concrete, allow it to cure, and remove the forms. 7. Install any needed erosion control materials. (1) Figure C. 131 Repair of abutment face C Abutment Stabilization In addition to providing end support for the bridge deck, an abutment also acts as a retaining wall and is subject to horizontal earth pressures. These pressures coupled with the dynamic loading of vehicle traffic has the tendency to push out and rotate (tip over) the abutment, especially if the fill behind the abutment is unstable or the abutment is not adequately anchored. If the abutment is unstable, it may be shored or fixed using guylines from shore anchorages or a deadman tie-back system. (4)(1) A deadman is a heavy mass (weight) usually concrete blocks attached to the abutment with a long steel rod and located in stable earth far behind the abutment. This provides an anchor that prevents overturning of the abutment. Good maintenance planning for installation of a deadman anchorage includes:

194 (1) using a professionally qualified engineer to calculate the magnitude of the forces to be resisted by the deadman, to determine the required size of the deadman and the restraining rod, and to determine if piles are required; (2) providing the necessary resources including excavation equipment, light lifting equipment, concrete, drills, miscellaneous hand tools, and any shoring as needed. Procedure 1. Excavate the area where the deadmen are to be placed and provide a trench for the restraining rods. (Excavation behind an abutment may present a high potential for a cave-in. Shoring may be needed.) 2. Place formwork and concrete for the deadmen or drive a pile anchor approximately 3 feet on either side of the approach to the bridge. These anchors should be from 60 to 100 feet from the face of the existing abutment. No formwork is required if the soil conditions are stable enough for the walls of the excavation to act as earthen forms. 3. Drill a hole in the wall on both sides of the abutment and in a position outside and in line with the abutment cap. Run a restraining rod or cable from the deadman through the hole in the wall. 4. Place a beam (example: steel wafer) on the outside of the cap. 5. Connect the retaining rod or cable to the beam and place tension on the rods or cables. 6. Wrap and coat them with tar (or provide other means to protect the rods from corrosion) 7. Grout holes in the wall. 8. Backfill the excavated area. (1) This technique can be used on smaller abutments to help draw the abutment back to its original position and to hold it in place. (4) Figure C. 132 Abutment held in place with a deadman C Repair to Increase the Load Carrying Capacity of Deteriorated Abutment Walls or Bridge Seats This repair procedure is for when concrete in abutment walls has deteriorated and the load carrying capability of abutments needs to be increased. (10) Consult with the Bridge management section for beam and angle sizes and spacings. (10)

195 Procedure 1. Excavate to expose the concrete footing if necessary. 2. Bolt steel plates to the footings with two drilled in 19 nun (3/4") diameter anchor bolts. 3. Secure steel vertical columns to front face of abutment wall with drilled in 20 mm diameter anchor bolts. 4. Place a cap on top of the vertical columns and diagonal bracing under slab or beams. Secure cap with L 102 x 76 x Shim up between the columns, steel beam caps and horizontal stringers or slab as necessary with steel shims. 6. Field weld all connections that are not bolted. 7. Backfill any excavation that was required to expose the footing. (10) Figure C. 133 Half Transverse Section at Abutment

196 Figure C. 134 Figure C

197 Figure C. 136 C Repair to Protect Exposed Abutment Footing and/or Piling This procedure is for when Exposed abutment footings and/or piling on ditches or waterways have been deepened and protection is required to prevent erosion and inward movement of the abutment. (10) This method has been used in many locations, however, this installation will reduce the waterway opening and may trap debris. (10) Procedure 1. Place sheet piling (MP-I02 or other) along the front of the abutments from end of wingwall to end of wingwall to a depth of at least 1 m below the channel ground line. 2. Place an 191 mm x 191 mm treated timber post between the front face of abutment and sheet piling and fasten it to the sheet piling with 13 rom diameter lag screws. 3. Place an adequate beam above sheeting and cinch anchor this bearing pile to the abutment over the sheet piling only if necessary. 4. If necessary place beam struts and angle braces between abutments. Size of struts and bracing to be determined by consulting with the Office of Bridges and Structures. (10)

198 Figure C. 137 C Repair of Partially Spalled and Cracked Concrete Abutment and Footings A cofferdam and water pump may be necessary to control the water while repairs are being made. (10) Procedure 1. Construct cofferdam and pump out water if necessary. 2. Cut out the deteriorated concrete on the face of abutments down to good concrete or to a depth that exposes the reinforcement in the near face. 3. Form and add a new reinforcement mat and concrete to make the abutment 100 to 150 mm thicker. Use 3Y43 concrete or equal for repairs. (10)

199 Figure C. 138 Plan View Figure C. 139 Detail C Figure C. 140 C Install L-Shaped Abutment Jacket to Strengthen Stone Abutments Equipment Concrete Mixer (8) Material Concrete Reinforcing Steel Sandbags (8) Procedure 1. Construct sandbag cofferdam and excavate for footing to sound material. 2. Clean existing stone that is to come in contact with new concrete. 3. Set dowels with non-shrink grout or approved adhesive in existing open stone joint at 24 in. horizontally and vertically with 1 ft-3 in. embedment length

200 4. Set concrete forms and place concrete as required against existing stone abutment. Prior to placing concrete, apply epoxy bonding compound to stone that is to come in contact with new concrete. 5. Place forms, reinforcing steel, and concrete for new abutment footing. 6. Place forms, reinforcing steel, and concrete for new abutment wall. 7. Remove loads from the existing abutment by jacking or using needle beams as necessary. 8. Install new bearings or move old bearings as necessary. Reload the newly jacketed abutment. 9. Remove formwork and the cofferdam. (8) Figure C. 141 Figure C

201 C Repoint Masonry Walls Work should not be scheduled when there is any possibility of freezing temperatures. (8) This work is on all masonry substructure units; abutments, wingwalls and piers, and sufficient area adjacent to them to allow for any necessary excavation and the placing of water control devices. (8) The work involves pointing and repointing masonry elements is substructure units with mortar. The work can include, but is not limited to, excavating materials; installing sheeting or other water control devices such as bagged concrete riprap; removal of deteriorated concrete with hand or power tools; cleaning surfaces to be mortared with high pressure water, air-blasting or sand-blasting, as appropriate and necessary; mixing mortar and mortaring prepared joints. (8) Equipment Pressure Grouting Equip (8) Material Concrete (8) Procedure 1. Thoroughly clean masonry joints of all loose and unsound mortar and foreign material. 2. Saturate the joint surfaces with clean water before applying mortar. 3. Fill all the voids with mortar, making the surface flush with the adjacent face of the structure. 4. Cure all new mortar with wet burlap or clear curing compound. 5. Clean the face of the masonry. (8) Figure C

202 C Repair Backwall This procedure is for abutment backwalls for the full width of the structure between abutment parapets, and to a depth sufficiently below the bridge seat elevation to permit the installation of dowels and/or the proper lapping of reinforcement bars. The work involves repairing or replacing all or portions of concrete masonry backwalls. The work can include, but is not limited to, installing sheeting, if necessary, and excavating pavement and other roadway material behind backwalls to gain access to them; removing deteriorated or damaged concrete. reinforcing steel; or masonry; drilling and installing adhesive anchored or grouted dowels; installing reinforcing steel; constructing forms; placing concrete; replacing and pointing masonry elements; pressure grouting masonry; epoxy pressure grouting; and restoring all pavement and other roadway material behind the backwalls. In some instances removal of concrete in a backwall is primarily for the purpose of gaining access to anchorages for armored or modular dams, or making minor repairs to concrete associated with deck joints and is within the defined work area for an activity involving deck joints. (8) Equipment Welding Equip Concrete Mixer Backhoe or Gradall Roller or Tamper (8) Material Reinforcing Steel Concrete (8) Procedure 1. Temporarily tack weld the abutment side of steel armored joints, plate expansion dams, or toothed expansion dams to the deck side of the joint assembly. 2. Cut and excavate the approach slab or pavement to allow access to the backwall. 3. Remove deteriorated concrete or masonry and/or reinforcing bars from the backwall. 4. Place replacement reinforcing bars by tying them into existing bars in the abutment or by grouting dowel bars into the abutment. 5. Place forms for concrete. 6. Place and cure concrete. Insure concrete is placed beneath existing joints. 7. Remove forms and temporary tack welds on joints or dams. 8. Backfill and compact subgrade under the approach slab or pavement. 9. Patch the approach slab or pavement. (8) Welding details for this repair should be furnished by the Bridge Engineer and the welding should be accomplished by personnel certified for the type and position the weld required. (8)

203 Figure C. 144 Typical Joint Details Figure C. 145 Cross Sections of Abutments With Backwalls

204 C Replace Concrete Wingwalls Equipment Gradall or Backhoe Concrete Mixer (8) Material Concrete Reinforcing Steel Stone for scour protections (8) Procedure 1. Remove existing wingwalls and excavate to sound material. 2. Clean all concrete that is to come in contact with new concrete. Chip and clean existing concrete to remove any unsound material and laitances. 3. Drill and set dowels. 4. Set forms, reinforcing steel and place concrete. Just prior to placing concrete, apply epoxy bonding compound to all existing cleaned concrete that is to come in contact with fresh new concrete. 5. Prior to placing concrete, provide for adequately reinforced weep holes. 6. Backfill adequately cured concrete wingwalls. Suitable filter shall be provided for weep holes. 7. Provide scour protection. (8) Figure C. 146 Rock Slope Protection

205 Figure C. 147 Rock Slope Protections C Repair Broken or Deteriorated Concrete Wingwalls Portions of an otherwise sound wing wall may be broken off by frost heave, ice that forms in voids created by fill settlement adjacent to the wall, ice in cracks, voids in the concrete, or insufficient air entrainment voids. Deterioration may result from de-icing and from salt-rich snow and ice being plowed onto the wing walls where it piles up. Weak aggregate in the original concrete mix can also contribute to wing wall deterioration. Losing portions of a wing wall can result in erosion of the fill and further damage to the bridge approach. The cause of the wing wall failure must be determined so it can be corrected as part of the wing wall repair process. Concrete forming should be preplanned and the forming materials cut to size in advance, if possible. Any excavation required to gain sufficient working access and to facilitate removal of defective concrete can be accomplished in advance of the wing wall repair. Materials and equipment typically needed to make this type of repair vary widely but often include excavating equipment such as a backhoe, an air drill, tie screws or equivalent bolts, wood spacers (walers, etc.), reinforcing bars, granular backfill material, hand tools, concrete removal equipment, anchor bolts and anchors, plywood forming, portland cement concrete, epoxy bonding agent, nonshrink grout, and miscellaneous hardware. Everything needs to be readily available to limit the exposure of maintenance personnel to traffic and to expedite the repair operation. (1)

206 Equipment Concrete Mixer Gradall or Backhoe (8) Material Concrete Mixer Reinforcing Steel (8) Procedure 1. Excavate as required to be able to set the dowels and the concrete forms. 2. Remove all fractured or deteriorated concrete to sound concrete by chipping and then blast-clean to remove all loosened surface material. 3. Drill and set form anchor bolts and dowels. Typically, dowels 13 mm in diameter (no. 4 bars) are placed a minimum of 225 mm (9 inches) into sound concrete and set with nonshrink grout, 150 mm (18 inches) center-to-center, both front and back. 4. Crosslace the 13-mm (no. 4) reinforcing steel bars and set the concrete forms. 5. Just before placing the concrete, apply an epoxy bonding agent to all existing concrete that will contact the new concrete. 6. Before backfilling with granular material, cure the new concrete a minimum of 7 days or until the concrete has developed sufficient strength to resist the lateral pressures of the backfill. (1)

207 Figure C. 148 C Repair of Concrete Wingwall That is Breaking and Tipping Outward on One Side of Abutment Procedure 1. Remove the soil from behind the wingwall down to the depth necessary to place the posts and deadman. 2. Drive steel I beam (or equal) posts a minimum of 1.2 m below the bottom of the footing. 3. Place a concrete deadman and/or piling in the fill parallel to the roadway or wingwall as necessary. 4. Drill 35 mm or 41 mm diameter holes through the wingwalls for 30 mm ( 1 1/8") or 36 mm (1 3/8") diameter threaded bolts respectively. 5. For anchorage on the exposed face of the wingwalls, drill two 35 mm diameter holes in steel channels and place 32 mm diameter rod (with 300 to 450 mm of thread) with a loop on one end through the wingwall. 6. Fasten the cables to the eyebolts and deadman and draw the cables tight. 7. Place the soil back in 200 mm maximum lifts with J-tamper

208 Use the larger bolts on wingwalls over 2.4 m in height on large walls or high abutments. (10) Figure C. 149 Plan View Figure C. 150 Section A-A C Repair of Concrete Wingwalls That Are Breaking and Tipping Outward on Both Sides of Abutment Procedure 1. Remove the soil from behind each wingwall down to the depth required to pull the wingwall back to its original position. 2. Drill 32 mm or 41 mm diameter holes in one wingwall for 27 mm (1 ") or 36 mm (1 3/8") threaded bolts respectively. 3. If the wingwalls are in line with each other, drill horizontally through the roadway fill with a sinker or rock drill using a 13 mm or 19 mm diameter rod. 4. Fasten a 19 mm diameter galvanized cable to the rod and pull the rod and cable back through the fill. 5. Drill 32 mm or 41 mm diameter holes in the other wingwall for 27 mm (1 ") or 36 mm (1 3/8") diameter threaded bolts respectively. 6. For anchorage on the exposed face of the wingwalls, drill two 41 mm diameter holes in steel channels and place 36 mm (1 3/8") diameter eyebolt (with 300 to 450 mm of thread) with a loop on one end through the wingwall. 7. Fasten the cable to bolt loops and draw the cables tight by tightening up the nuts on the eyebolts. NOTE: Use the larger bolts on wingwalls over 2.4 m in height

209 8. Backfill the excavation in 200 mm maximum lifts using soil removed from the excavation and hand compaction equipment. Consult Office of Bridges and Structures on large walls or high abutments. (10) Figure C. 151 C Extend Wingwalls with Gabions This repair is on the full length and depth of abutment wingwalls from, and including, the abutments parapets to the end of the wingwalls. This procedure involves repairing all or portions of concrete or masonry abutments. The work can include, but is not limited to, installing sheeting when necessary and excavating material retained by or protecting the wingwall; removing deteriorated or damaged concrete, reinforcing steel or masonry; drilling and installing dowels; installing reinforcing steel; constructing forms; placing concrete; replacing and pointing masonry elements; pressure grouting masonry; epoxy pressure grouting; and replacing excavated material. (8) Equipment Gradall or Backhoe Concrete Mixer (for concrete (pad) Tamper or Roller Sweeper (8) Material Stone for gabions Gabion basket and ties Geotextile fabric (for granular bed) Aggregate for base Water (8) Procedure 1. Excavate and remove all unsuitable material below the wingwall extension

210 2. As required, replace unsuitable material with acceptable granular material and thoroughly compact the entire foundation to a firm, even surface. 3. Place specified geotextile fabric or place cement concrete pad. 4. Assemble, bind, join, and place gabions. 5. Fill Type A gabions by hand or small power equipment, with specified aggregate. 6. As specified, secure lid to sides, ends, and diaphragms using connecting wire.(8) Figure C. 152 Typical Gabions with Granular Bed

211 Figure C. 153 Wingwall Cross-Section C Repair to Stabilize Existing Wingwalls with Gabions Equipment Gradall or backhoe Concrete Mixer (8) Material Stone for gabions Gabion basket and ties Geotextile fabric (for granular bed) Aggregate for base (8) Procedure 1. Excavate and remove all unsuitable material below the face of wingwall to be retained or stabilized

212 2. As required, replace unsuitable material with acceptable granular material and thoroughly compact the entire foundation to a firm, even surface. 3. Place specified geotextile fabric or place cement concrete pad. 4. Assemble, bind, join, and place gabions. 5. Fill Type A gabions by hand, and Type B gabions by hand or small power equipment, with specified aggregate. 6. As specified, secure lid to sides, ends, and diaphragms using connecting wire. 7. Place specified large rock buttress at a one-to-one slope. (8) Figure C

213 Figure C. 155 Wingwall Cross-Section C Repair to Protect Exposed Abutment Footing and/or Piling This procedure is for when Exposed abutment footings and/or piling on ditches or waterways have been deepened and protection is required to prevent erosion and inward movement of the abutment. (10) This method has been used in many locations, however, this installation will reduce the waterway opening and may trap debris. Therefore, installation should be approved by the Bridge Engineer. (10) Procedure 1. Place sheet piling (MP-I02 or other) along the front of the abutments from end of wingwall to end of wingwall to a depth of at least 1 m below the channel ground line. 2. Place an 191 mm x 191 mm treated timber post between the front face of abutment and sheet piling and fasten it to the sheet piling with 13 mm diameter lag screws. 3. Place an adequate beam above sheeting and cinch anchor this bearing pile to the abutment over the sheet piling only if necessary. 4. If necessary place beam struts and angle braces between abutments. Size of struts and bracing to be determined by consulting with the Office of Bridges and Structures. (10)

214 Figure C. 156 C Repairing Spread Footing Deterioration of a concrete spread footing can include breaking off of the footing projections or spalling of the sides. Severe deterioration may be caused by collision of ice and/or debris against the upstream side of the footing, water penetration resulting in corrosion of reinforcing steel, or initial construction using poor materials. Because the load of the bridge was originally designed to be supported by a uniform distribution of pressure on the material under the footing, the area of the footing must not be reduced. Installing a cofferdam, pumping, and dewatering, as needed, will allow the repair to proceed in a dry working environment. (1) Procedure 1. Keep the work area clear of water with diversion channels, cofferdams, sandbags, or sheet piling, as required. 2. Chip away the deteriorated concrete until sound concrete is reached. Clean away all loose concrete with air-blasting or other methods. 3. Install reinforcing steel, anchors, and rods, as needed. 4. Construct forms that adequately restore the footing dimensions of the original design size. Commonly, the footing is extended to cover a large area and the sides of the footing are extended downward if any undermining has occurred. 5. Apply any bonding compounds or a neat cement paste for bonding just before placing the new concrete into the forms

215 6. Mix and place the new concrete, using a strong mix with a low slump. Vibrate the concrete thoroughly to ensure dense placement and a good bond to the existing concrete surface. 7. After the new concrete has cured for at least 3 days, remove any cofferdam and restore the stream channel to its proper course. Where shotcrete is used extensively on other parts of the structure, the repairs may be made using shotcrete. (1) C Underpin Footing with Concrete or Pumped Grout All footings on all substructures units; abutments, wingwalls, piers, and sufficient area adjacent to them to allow for any necessary excavation and the placing of water control devices. (8) Underpinning concrete or masonry footing with concrete or pumped grout. The work can include, but its not limited to, excavating material; installing sheeting or other water control devices such as bagged concrete riprap or nylon tubes filled with pumped grout; erecting temporary supports to permit the removal of unsatisfactory material; constructing forms; drilling and grouting dowels; placing reinforcing steel; placing concrete or pumping grout; and replacing excavated material. When protective material such as riprap is excavated to gain access to the work area, it should be replaced in conformance with work description in appropriate activities, such as Activity B745301, Rock protection. However, a separate report is not required, and the work should be reported under this activity. (8) Equipment Concrete Mixer Gradall or backhoe (8) Material Concrete (8) Procedure 1. Construct sandbag cofferdam to an elevation above the water level or divert stream using temporary pipes. 2. Clean all exposed concrete of marine growth and remove loose or deteriorated concrete. 3. Excavate as required to sound material. 4. Drill required dowel holes, set and install dowels, set additional reinforcing, and place forms. 5. Place and compact the concrete, making sure that scour area is filled. 6. Remove forms and protect against continued stream bed erosion with gabions or stone riprap. (8)

216 Figure C. 157 Underpinning Underscoured Figure C. 158 General plan curtain wall and underpinning abutment C Underpin Footing Using Tremie Concrete Equipment Concrete Mixer Gradall or backhoe (8) Material Concrete (8)

217 Procedure 1. Clean all exposed concrete of marine growth and remove loose or deteriorated concrete. 2. Excavate as required to sound material. 3. Place concrete riprap bags around scour area. Where the scoured-out material is finegrained, a filter should be placed prior to placing the riprap. 4. Pump or tremie concrete into damaged area. 5. Protect against continued stream bed erosion as required by rebuilding stream bed with properly designed riprap or by paving the stream bed. (8) Figure C. 159 C Repair Abutment Slopewall If the bridge is a water crossing, the work can usually be done most conveniently during the middle to late summer season when water levels are normally low. (8) The entire area of existing slopewalls and sufficient additional area to permit any necessary excavation and installation of cutoff or toe walls. Repairing or replacing portions of an existing slopewall, composed of the same materials. The work can include, but is not limited to, installing sheeting or other water control devices; excavating material; removing deteriorated or damaged concrete masonry units; constructing forms; grading surfaces and install-ing aggregate and/or geotextiles; placing reinforcing steel; placing concrete; laying concrete blocks or stones; and mortaring joints. (8) Equipment Gradall or backhoe Air compressor and Jack Hammer Concrete Mixer (8) Material Concrete and/or concrete blocks Joint sealing material Sand and fine aggregate (8)

218 Procedure 1. Excavate for a new end wall around toe of slope to extend to below scour line or to solid rock. 2. Set up forms for end wall and place concrete. 3. Fill voids in existing sound slope protection by removing sections of protection and filling voids with crushed store. 4. Grade and place bedding for slope wall extension. 5. Replace damaged sections, sections removed to fill voids with concrete, and place extension. 6. Fill voids in embankment and protect slopes adjacent to stone protection with large stone riprap. (8) Figure C

219 Figure C. 161 C Construct New Abutment Slopewall If the bridge is a water crossing, the work can usually be done most conveniently during the middle to late summer season when water levels are normally low. (8) The filled area in front of a stub or semi-stub abutment extending from a line drawn perpendicular to the centerline of the bridge from the end of one wing to a similar line drawn from the other wing between the abutment structure at the top and the stream bed or shoulder depending upon whether the structure is a water crossing or an overpass at the bottom (see sketch). (8) Constructing new precast cement concrete block, cast-in-place cement concrete slab, stone or random stone abutment slope walls within the work area. The work can include, but is not limited to, installing sheeting or other water control devices; excavating material; removing deteriorated or damaged concrete masonry units; constructing forms; grading surfaces and installing aggregate and/or geotextiles; placing reinforcing steel; placing concrete; laying concrete blocks or stones; and mortaring joints. (8) Equipment Gradall or backhoe Concrete Mixer Jack Hammer (8) Material Concrete Concrete blocks Reinforcing Steel Geotextiles

220 Aggregate (8) Procedure 1. Remove existing deteriorated abutment slopewall. 2. Regrade slope and place sand and geotextiles as required for precast cement concrete blocks or stone. 3. Place forms and concrete, precast concrete blocks, or stones. 4. Construct cut-off and toe walls. 5. Seal joints as required. (8) Figure C. 162 C Piles, Piers and Bent Repair Most piles require little maintenance because the material into which they are driven protects them or deterioration is not common. Where piles are exposed (whether by design or by scour), there are potential problems. These problems include scaling and spalling of concrete piles, corrosion of metal piles, or decay in timber piles, and buckling in all types if the unsupported length of the pile becomes excessive. (1) The typical repair involving concrete columns and piles is to place a concrete jacket around the member to protect it from further deterioration or to restore the structural integrity of the member. The repair can be made with a standard wood or metal form work which is removed after curing or a fiberglass form that remains in place and helps protect the surface of the member. (4) C Repair Deteriorated Concrete Pile This repair method is used for piles that have been damaged or deteriorated to the point that structural integrity of the member is in question. In this procedure, the pile is encased with a concrete jacket reinforced with epoxy coated reinforcing steel. (Figure C. 164) Fiberglass forms can be used to prevent further deterioration or restore structural integrity to piles and columns. (4) Jackets are used for protection of all types of piles: concrete, steel, and timber. The jacket can protect against abrasion damage, repair lost cross section, or accomplish both purposes. If the jacket is for protection only, it typically consists of a liner placed around the area to be protected with a cementitious grout or epoxy resin pumped into the annular

221 opening between the existing concrete and the liner. If the jacket is intended to repair structural damage, the liner will provide space for reinforcing steel, and the space between the liner and the old pile will be filled with concrete. Deteriorated reinforced-concrete and prestressed-concrete piles can also be encased with a concrete jacket. Encasement will compensate for the cross-sectional loss and strengthen the pile. Concrete jackets can cause accelerated corrosion on a steel pile when both concrete and water are in contact with the steel. A corrosion cell will develop either below the bottom or above the top of the jacket. Thus, concrete jackets should be extended well into the mud zone and also well above the high water line. Steel piles must be protected with coatings that prevent dissolved oxygen from contacting the steel. Epoxy coating systems and polyvinyl chloride barriers have been used. While preventive maintenance for piles is thought of most often in terms of marine environments, there are significant concerns about the use in non-marine environments of steel piles driven into soil for foundation support. Equipment Concrete Mixer Welding Equipment Access Equip (8) Material Concrete Reinforcing Steel and steel mesh Forming jacket (8) Procedure 1. Remove deteriorated concrete from existing piles if required. 2. Clean the pile to ensure proper bonding with the jacket. 3. Sand-blast exposed rebars to remove corrosion and rust and replace any steel as required. 4. Install new mesh reinforcing cage around pile. Use spacers to keep the form in the proper position. 5. Treat the inside face of the forms with a release agent, and set the forms for the concrete jacket around the rebar cage and pile and seal the bottom of form against pile surface. If fiberglass forms are used they should be a minimum of 1/8-inch in thickness with noncorrosive standoffs and a compressible sealing strip at the bottom. 6. Pump concrete into the form through the opening at the top. Finish the concrete at the top of the form. Sulfate-resistant concrete should be used in saltwater environments. (8)

222 Figure C. 163 Typical round pile Figure C. 164 Standard concrete pile jacket with steel reinforcing cage C Pile Replacement It may be easier to replace a damaged pile rather than repair it. Replacement is accomplished by cutting a hole in the deck and driving the pile through the hole. Since the pile is driven from the deck, the deck must be capable of supporting the necessary pile-driving equipment. Maintenance operation planning includes the following steps: (1) Determine if the bridge will support pile-driving equipment. If it will not, an alternative is to drive from a barge or from dry land if conditions permit. Make provisions to restrict traffic from the work area

223 Typical equipment needs include pile-driving, wood-cutting, and deck-patching equipment; piles; come-alongs; jacks; flashing; fasteners; cutting torches; and pavementbreaking, concrete-sawing, and welding equipment. (1) Procedure 1. If the deck is overlaid with asphalt or concrete, locate the centerline of the stringers closest to the pile replacement. 2. Cut through the overlay and the deck along the centerline of the stringer. Remove sufficient deck to permit the pile to go through the hole adjacent to the cap. 3. If cross bracing is present, remove it from between the piles and on the side of the bent where the new pile will be driven. 4. Set the pile at a slight batter so it will be plumb when it is driven and pulled under the cap. Drive the pile to the specified bearing. 5. Install U-clamps and blocking around the pile to be replaced. Place a jack on blocking and jack the cap up approximately 13 mm (about 0.5 inch). 6. Cut the pile 6 mm (about 0.25 inch) below the cap and pull the pile into position under the cap. 7. Positioning the pile can be accomplished by using come-alongs to pull against adjacent bents. Place copper sheeting on a timber pile head. On a steel bent, the pile is welded to the cap. 8. Lower the jack and strap in place. 9. Reconstruct cross bracing on bent piles. 10. Close deck holes and restore normal traffic flow. This process may also be used for strengthening an existing bent. (1) C Casting Subfooting to Cap Piles Badly deteriorated piles that are exposed under a footing must be repaired before the void under the footing is filled. If accessible, timber or steel piles may be spliced. Where there is no room to implement a repair by adding sections, a possible alternate repair process may be used. An alternate process is outlined in the following steps: 1. Cut out the deteriorated portion of the pile from the footing bottom to the depth of the sound piling material. 2. Form and place new concrete from the footing bottom to about 150 mm (about 6 inches) below the new top of the pile, using Class I concrete. 3. When topping out the new concrete, maintain a hydrostatic head at the interface between the fresh concrete and the old footing. Attempt to eliminate voids at the interface. Pumping or pressure grouting may be required after the concrete cures. 4. The repair must be phased so that there is always sufficient support to the structure to carry the required load. 5. Fill all of the voids. When the void that exposed the piles is caused by erosion, some measures must be taken to prevent its recurrence. (1) C Repairing Concrete or Masonry Piers Repairing all or portions of concrete or masonry piers. The work can include, but is not limited to, installing sheeting when necessary and excavating material temporarily modifying superstructures to accept jacking loads, providing temporary supports for

224 jacking; removing loads from piers either by jacking from below or using needle beams from above; removing dowels; installing reinforcing steel; constructing forms; placing concrete; replacing and pointing masonry elements; pressure grouting masonry; epoxy pressure grouting; and replacing excavated material. (8) Equipment Concrete Mixer Welding Equip Scaffolding or lifting equip (8) Material Concrete Reinforcing Steel (8) Procedure 1. Saw cut the boundaries of the deteriorated concrete to be removed to a depth of 3/4". 2. Remove deteriorated concrete by chipping with light power tools. 3. Blast clean exposed reinforcing bars of all rust and foreign materials. Replace deteriorated bar sections as necessary. 4. Place reinforcing mesh as necessary. 5. Blast clean the existing concrete to be patched to remove loose concrete chips and laitances. 6. Place forms, coat existing concrete surfaced with epoxy bonding agent, and place concrete. 7. Remove forms and finish surfaces after concrete has cured. C Repair of Tilted Pier and Deck Equipment Concrete Mixer Bridge Jacks Access Equip (8) Material Concrete Reinforcing Steel (8) Procedure 1. Follow the procedures for activity Underpin Footing (C ) to stabilize the pier base. 2. Construct first stage of pier enlargement to above water level. 3. After the new structure has attained design strength, place jacks on the enlargement and jack the superstructure back to its original grade. 4. Construct the second stage portion of the pier to permit removal of temporary supports. 5. Once the second stage concrete has attained design strength, remove temporary supports. 6. Repair deck and superstructure

225 Figure C. 165 C Repair of Cracked Hammer Head Piers Using Epoxy Grout and Reinforcement Equipment Injection equip Concrete Drill Access Equip (8) Material Epoxy Grout No. 4 Reinforcing Steel (8) Procedure 1. Clean crack of all loose concrete and laitances. 2. Seal crack with epoxy grout. 3. Drill holes perpendicular to the crack place

226 4. Inject epoxy grout into the drill holes under low pressure. 5. Place the rebars into the drill holes. 6. Clean any excess grout. (8) Figure C. 166 Method used to locate intercepts and drill entry points Figure C. 167 Geometry to establish drill entry points

227 C Repair Cracked Hammer Head Piers by Post Tensioning Equipment Jack Epoxy Injecting Equip Access Equip (8) Material Epoxy Grout Post-Tensioning Bars as Fittings (8) Procedure 1. Erect all intermediate supports and anchorage assembly at one end of pier cap. Locate existing stirrups and horizontal steel in pier cap prior to installing expansion bolts for the supports. 2. Insert corrugated pipes with pre-grouted thread-bars inside to the intermediate supports or the pier cap. 3. Erect the smooth PVC pipes with threadbars inside to the intermediate supports or the pier cap. 4. Erect anchorage assembly at other end of pier cap. 5. Add anchor plates with steel tubes to both assemblies, pack tubes with plastic corrosion inhibitor and add anchor units on both ends. 6. Initially post-tension all threadbars to 10 kips in order to seat the post-tensioning system on the pier cap. 7. Epoxy inject all cracks in the pier cap. 8. After the injected epoxy has hardened, post-tension the system to the required load per bar. 9. Install sealing caps with plastic corrosion inhibitor and plastic nuts. (8)

228 Figure C. 168 C Repair of Steel Piles Using Channel Splice Steel piles may be damaged, particularly if they are located in waterways where they may be struck by heavy barges or if they are placed near roadway work zones where they may be struck by heavy equipment. The latter scenario is less common. Damage in the form of bent, torn, or cut flanges may reduce the cross section, and hence the load-bearing capacity, of the pile, requiring repair. More commonly, steel H-piles may become severely corroded in a relatively short section near the main water line in a waterway or as the result of unusual conditions such as broken drains. An otherwise sound steel pile or one that cannot be easily replaced or supplemented because of access or scheduling may be strengthened by repair with bolted channels as a temporary measure. Maintenance operation planning should include the following actions: (1) select appropriate channel size to meet strength and dimensional requirements; (2) determine length of damaged area and secure steel channels of selected size that have been fabricated in appropriate lengths with necessary hardware; and (3) assemble equipment and tools needed (such as equipment to drill bolt holes), protective coating materials, and necessary staging. (1) Procedure 1. Clean the damaged pile. 2. Locate the extreme limits of the deteriorated section. The repair channel section should be about 0.5 meter (about 18 inches) longer than the distance between these limits. 3. Thoroughly clean the area to which the channel is to be bolted. 4. Clamp the channel section in place against the pile

229 5. Locate and drill holes for high-strength bolts through the channel and the pile section. 6. Place bolts and secure the channel. 7. Remove the clamps. 8. If the pile repair is above the water, coat the entire area with a protective coating material. 9. For long-term rehabilitation, steel piles should be encased with a concrete jacket. This procedure can also be used to add a new section of pile above a damaged area. (1) Figure C. 169 Steel pile strengthening C Repair Steel H-Pile Bents With Concrete Jacket This procedure is for piling that is badly rusted or damaged at or near the water line. Check with Bridge Engineer to ensure adequate load carrying capacity of repaired pile. (10) Procedure 1. Remove rust from inplace piling by scraping, sandblasting or other methods. 2. Make a split steel pile shell casing. 3. Place it around the damaged piling. 4. Weld straps on each side, paint the steel shell and drive the casings approximately 600 mm into the ground

230 5. Pump the water out of the casing if necessary. 6. Fill the casing with approved concrete. (10) Figure C. 170 C Strengthen Existing Cap The need to increase the load capacity of a bridge may arise from improper sizes or defects in a particular member. An example is wood pier caps that have developed large lengthwise shrinkage cracks or a large number of splits near bolt fasteners. A structural analysis may indicate such caps rate significantly lower than other members because of these defects. If the original cap is still in good structural condition and no decay is evident, strengthening the cap is often easier and cheaper than replacing it. In some cases, access limitations or other factors may make it very difficult to replace a cap. Thus, strengthening the cap is the most logical maintenance process. Good maintenance planning for cap strengthening should ensure that the existing cap and columns are in good condition, that the new section (as strengthened) will meet the design analysis load conditions, and that the appropriate resources are available (heavy-duty drilling equipment, light lifting equipment, access to the pile cap, wrenches, and small hand tools). (1) Equipment Power Drill Clamps (8) Material Shims Rings Bolts O.G. Washers

231 Wood Preservative (8) Procedure 1. Construct scaffolding, as needed, around existing bent. 2. If the pile diameter is wider than the existing cap, notch the existing piles or columns to accommodate the new timber cap members. 3. Snugly place the new members against the existing cap and stringers, and temporarily clamp them in place. 4. Drill 21-mm (13/16-inch) holes for 19-mm (3/4-inch) bolts and treat with preservative. 5. Insert the bolts, tighten them down, and remove the clamps. 6. Remove scaffolding, if any was used. (1) Figure C. 171 Figure C. 172 C Replacing Timber Caps A common maintenance problem with pile caps is decay followed by longitudinal cracks and crushing from the load on the cap. When these problems arise, the pile cap must be replaced. The superstructure is jacked either from the existing columns or from a temporary bent. The decayed cap is removed and a new cap is secured in position. To avoid future decay, timber pile caps that have deteriorated may be replaced with 300-mm (12-inch) steel beam caps. Stiffeners may be welded between the flanges directly over the piling. The steel cap is secured to the piling with a piece of 75-mm (3-inch) flat stock bent to encircle the top of the pile and welded to the bottom of the cap. (1) C Repairing Rotated Caps When timber pile abutments are pushed forward by the earthen fill that the abutment is retaining, causing the pile cap to rotate, either the pile stays are broken off or the abutment was constructed without stays. Abutments that are too high can also cause this problem. (1) Procedure 1. Remove all earth from behind the abutment. (Excavation behind an abutment may present a high potential for a cave-in. Shoring may be needed. (13) ) 2. Pull the piles and caps back into position. 3. Repair or install the pile stays. 4. Bury or drive deadmen behind the abutment. Then fasten and tighten the cables to the piles with eyebolts, using the size of cables specified by a professionally qualified engineer. (1)

232 C Repair All or Nearly All Piles in a Timber Bent This procedure is for when all or nearly all of the piling are rotting at or near ground level. (10) Procedure 1. Install falsework on mud sill to hold up the timber cap. 2. Excavate down to sound timber and saw the piles off squarely to the same elevation. 3. Remove the rotted piles and other members. 4. Install a new 292 mm x 292 mm timber cap on existing piling with 19 mm (3/4") drift pins. 5. Cut and treat exposed ends and place new timber piling sections to fit between the new lower cap and inplace upper cap. 6. Consult the Office of Bridges and Structures if the new timber cap or piling provides less bearing areas than the existing cap and piling. 7. Fasten new pile sections into the lower and upper caps using boat spikes at each pile joint. 8. Install treated timber sway bracing using bolts and ogee washers. 9. Backfill excavation to original ground line. (10) Figure C. 173 Pier Elevation C Replacing Timber Pile Bent With Steel Columns Timber pilings that have decayed, have been weakened by insects or marine organisms, or have been structurally damaged by collision or overloading may be replaced with steel columns. Maintenance planning for such repair should (1) evaluate the condition of existing caps and existing piles below the surface; (2) determine any need for a cofferdam

233 to dewater the work area; (3) determine a method of temporary support for the superstructure during repairs; (4) make provisions to restrict traffic from the work area during repairs; and (5) procure necessary equipment and tools such as wood-cutting tools, welding and steel-cutting equipment, light lifting equipment, wrenches, and other small hand tools. (1) Procedure 1. Determine all cutoff points on the existing piles and the column length needed for the repair. 2. Construct temporary support for the superstructure before beginning the repair. 3. Construct a cofferdam (if needed) and dewater the work area. 4. Excavate so that the top of the footing will be a minimum of about 225 mm (about 9 inches) below the ground line. 5. Cut existing piles off so that they will project at least 300 mm (12 inches) into the new footing. 6. Separate the old sections of piling from the pier cap. 7. Form and place concrete footings over the existing pile stubs. 8. Place the anchor bolts in the footing concrete before the initial set of the concrete. 9. Cut the steel columns to the proper length and weld on the base plates. 10. After the concrete has reached the required strength, attach the new steel columns to the footings with nuts and washers. 11. Attach the top of the new columns to the existing pier caps with lag screws. 12. Remove all temporary supports, backfill where necessary, and remove the cofferdam (if one was used). (1) C Replace Single Pile Equipment Power Saw Pile Driver Come Along Jack, U-Clamps Blocking (8) Material Timber Pile Flashing Crossbracing Decking Overlay Material Wood Preservative (8)

234 Procedure 1. Cut through overlay and deck along center lines of adjacent stringers near pile to be replaced. Remove sufficient area of deck to permit pile to be driven. 2. Remove cross-bracing as necessary. 3. Drive pile at slight batter so it will be plumb when in final position. 4. Install U-Clamps and blocking on pile to be replaced as shown. Lift cap. 5. Cut new pile and pull into position under cap. 6. Install flashing and lower cap. 7. Remove existing pile and jack. 8. Install cross-bracing, deck, and overlay if appropriate. (8) Figure C. 174 C Strengthening by Installing Helper Timber Bents An existing substructure unit that is not capable of supporting its required load may be supplemented with a timber helper bent. One example is a concrete bridge pier in which seat damage is so acute that the bearings are affected and the beams may dislodge. In this case, a timber helper bent adjacent to the pier would support the load and preclude bridge failure if bearing failure did occur. The timber helper may also be used to reduce the span length and increase the bridge load-carrying capacity in a situation where the beams are weakened or were not designed for current legal loads. A professionally qualified structural engineer should determine the size and location of the helper bent. The engineer must also determine if the bridge can support a pile-driving rig or if the equipment can be located off the deck. A professionally qualified hydraulic engineer should determine if the additional restriction to stream flow that the helper bent will create is acceptable for hydraulic efficiency. Provisions should also be made to maintain traffic safely away from the work area. Equipment systems that may be needed include pile-driving equipment, lifting equipment, deck-cutting equipment, and perhaps scaffolding. (1) Procedure 1. If the deck is timber with an asphalt or concrete overlay, locate the centerline of the stringers closest to each pile location for the helper bent. If the deck is reinforced concrete, locate the piles so that the deck beams will not interfere with pile driving. 2. Cut holes in only one traffic lane at a time

235 3. If a timber deck does not have an overlay, cut the timber decking at the centerline of the stringer near the centerline of the bridge and remove the decking across the traveled lane. 4. Cut through any overlay and the timber deck along the centerline of the stringer. Remove sufficient amount of the timber decking to permit a pile to go through the hole. For a reinforced-concrete deck, remove a sufficient amount of concrete in a square pattern to permit a pile to go through the hole. Cut any reinforcing steel at the center of the hole and bend it out of the way of the pile to be inserted through the hole. 5. Set the piling and drive it to the required bearing capacity. 6. Cut off the piling approximately 6 mm (about 0.25 inch) above the bottom of the existing cap. If the existing cap has settled, allowance must be made for grade differential. 7. Place cover plates over deck holes, open the lane to traffic, move to the adjacent lane, and repeat the process as needed. 8. After all piles have been driven and cut off, jack up the superstructure approximately 13 mm (about 0.5 inch), using the existing pile bent. This may be accomplished with U-clamps and blocking supporting jacks against the beam bottoms. 9. Place timber caps over both rows of pilings. For end bents, only one row of piles and caps is required. 10. Lower the superstructure onto the new caps and strap each cap to its piling. Shimming may be required to obtain bearing between the superstructure and the timber caps. 11. Remove the deck plates and reconstruct the deck. If the deck is reinforced concrete, splice all reinforcing bars that were cut. Replace the deck one lane at a time. Sections of the deck under repair may be reopened to traffic if protected with steel plates. 12. Erect cross bracing on the new pile bent. For intermediate bents, cross bracing between the two new bents is also required. (1) An alternative temporary bent may be constructed with the following procedure: 1. Set piles and drive to the specified bearing capacity. 2. Cut off piles to allow for beams, neoprene pads, and wedge plates. 3. Connect 300-mm 300-mm (12-inch 12-inch) timber caps to plates with 22-mm (7/8-inch) 530-mm (1-foot 9-inch) headless drive spikes. 4. Connect timber brace to piles. 5. Set steel beams (such as W21 55 or W21 62) into position. 6. Jack beam from cap to obtain temporary bearing against superstructure. 7. Set neoprene pads into position. If necessary, cut them to obtain 225-mm 225-mm (9-inch 9-inch) pads. 8. Remove jacks and drive lag bolts. (1)

236 Figure C. 175 Strengthening an existing bent Figure C. 176 Temporary bent

237 Figure C. 177 Helper bent C Replace Pile Section Treated timber piles that have decayed or been damaged by fire or impact can be repaired without having to drive into the old pile, if the portion of the pile below the ground is still sound. The timber splice method should not be used when replacing piling in the abutments or end bents because it will not provide sufficient resistance to the overturning moment produced by the force of the fill against the back wall. Equipment Power Saw (8) Material Temporary Bent Shims Wood Preservative Replacement Pile Section (8) Procedure Alternate 1 1. Install temporary crutch bent near pile to be partially replaced. (Figure) 2. Install U-Clamps and jack on pile to be partially replaced. Lift cap. 3. Shim crutch bent to remove load from and lift span off of pile to be partially replaced. (8) 4. Remove the rotted section and above by sawing the pile off squarely. 5. Treat cut area with wood preservative. 6. Place a new. piece of timber pile (exact same length as piece removed) in the section and encase this section plus 600 mm on each side of saw cuts in a steel pile tube. Fill the void between the timber pile and steel tube with concrete. (10) 7. Paint the steel shell. 8. Remove crutch bent. (8)

238 Figure C. 178 Side Elevation Figure C. 179 Front elevation Figure C. 180 Pier Elevation Figure C

239 Figure C. 182 Split pile shell Procedure Alternate 2 1. After the required auxiliary support is in place, the old pile is cut off below the decayed or damaged area. 2. A new section of pile is cut about 150 mm (about 6 inches) shorter than the section removed. Plates are put in place on top of the existing pile and on the bottom of the new section of piling. 3. A 19-mm (3/4-inch) bolt with a nut is welded to the bottom plate, extending through a hole in the top plate. By adjusting the nut on the bolt, the new section of pile can be raised until it is securely seated against the bent cap. Care must be taken to raise the new section of piling far enough to cause the bent cap to lift from the adjacent piling. 4. After the new section is in place, 6-mm (1/4-inch) thick angles are welded between the plates at each corner. 5. Used girder plates or flat stock are then bolted to the timber pile and extended down on the original pile about 300 mm (about 12 inches). Using straps, the top of the pile is secured to the bent cap. 6. A 1 m 1 m 0.6 m (3 feet 3 feet 2 feet) block of dense concrete is placed around the pile. Any falsework erected may be removed after the concrete has been placed and has cured. (1) C Replace Timber Cross-Bracing Equipment Power Drill (8) Material Crossbracing Galvanized Nails Bolts, Washers and Nuts Wood Preservative Caulk/Grout (8) Procedure 1. Remove deteriorated cross-bracing. Plug old bolt holes with caulk/grout

240 2. Temporarily attach bracing to piles with galvanized nails. Nails should not interfere with bolt installation. 3. Drill and treat holes with wood preservative. 4. Place bolts, washers, and nuts. Tighten. (8) Figure C. 183 C Underwater Repair of Substructures Less than 20 years ago, only a few transportation agencies routinely inspected bridge substructures below the water line. Now, it is recognized that failure of structural elements under the water line can lead to bridge failures. Agencies now must identify all public highway bridges for which underwater inspections are necessary, define an appropriate inspection procedure for each bridge, and determine the necessary frequency of underwater inspection, which must not be less than every 5 years. Increased underwater inspection of bridges has made agencies more aware of the extent of deterioration below the water line, and consequently, has increased the need to respond with maintenance and repair of such damage. (1) C Engineering the Repair Solutions to underwater problems must be based on sound engineering. When underwater repairs have been necessary, bridge maintenance supervisors have tended to think in terms of dewatering the site. Cofferdams are installed and the damaged area is dewatered so that workers can perform the repair work using the same methods that would be used above the water line. The use of conventional abovewater methods provides confidence that quality of construction can be controlled. However, dewatering is not always feasible. Additionally, when underwater repairs are undertaken, there is sometimes a tendency to use one of a few commonly available techniques marketed for underwater applications, without considering alternatives that may be superior. (1) A major concern of underwater repair is that it may only hide a fundamental structural problem while this problem continues to grow worse. Repairing a condition that hides an uncorrected problem may be worse than doing nothing to the existing damage. For example, when contaminated concrete and corroded reinforcing steel are left in place to interface with new concrete, the corrosion process accelerates

241 Consequently, covering a reinforced-concrete member with a form or jacket that stays in place will not stop or prevent corrosion of the reinforcing steel; the member may look satisfactory while it is deteriorating to an unsafe condition. The repair should address the deterioration process in the structure s environment. If structural members are involved, the repair should be designed to provide the appropriate safety factor and structural redundancy needed. Unless special monitoring can be guaranteed, the repair should provide dependable service within the normal inspection cycle and the normal maintenance that can be reasonably expected from the responsible maintenance agency. (1) Since most bridge engineers are not divers, it is important that they understand the problems and limitations of performing repairs underwater. To improve the estimates of long-term maintainability in suggested repairs, some state DOTs have developed underwater inspection teams that include professionally qualified structural engineers. All repair schemes used above water are not cost effective when performed by divers underwater. The time and cost of labor is more of a consideration for underwater work. For example, it may be less expensive to accept that deterioration will continue and modify the load path by designing the repair to support the total load or by designing a supplemental supporting system than to remove and replace the damage. (1) C Control of Work in Waterways The restrictions and permits required by agencies such as the U.S. Environmental Protection Agency (EPA), the U.S. Army Corps of Engineers (CoE), and the Occupational Safety and Health Administration (OSHA) must be considered when planning underwater repair. A permit is required from the CoE if the work will involve a navigable waterway. EPA restricts introducing pollutants and contaminants into the water or air. OSHA regulates safe working conditions. Regulatory restrictions may significantly affect the cost of repair alternatives. For example, fewer environmental problems may result if an old element is left in place and supplemental support is added rather than the damaged material removed. It may also cause fewer environmental problems to prefabricate the new element before it is placed in the water. Most maintenance activities are allowed under CoE regulations in nationwide permits. However, the local CoE district office rulings and regulations should also be consulted. (1) C Protecting Underwater Bridge Elements Cementitious and epoxy coatings have been applied to underwater surfaces to protect concrete against abrasion and to cover cracks and make small repairs. The material is usually a thick mortar that is applied by hand. The cementitious products often include anti-washout admixtures and cure-set accelerators. Cementitious materials are mixed above the water line and delivered to divers in plastic bags. Epoxy resins applied underwater must perform satisfactorily and cure under both wet conditions and low surface temperature conditions. Underwater cathodic protection (CP) has achieved favorable results in preventing and halting corrosion of reinforcing steel. Cathodic protection can be provided for the reinforcing steel by either a sacrificial anode or an impressed current flow from a rectifier power source. In a marine environment and an underwater application, the sacrificial anode CP is often recommended because of the low-resistivity

242 environment. This system uses a metal (sacrificial) anode higher in galvanic series (metal activity scale) than the reinforcing steel to be protected. Zinc is often used as a sacrificial anode, but magnesium and aluminum are also sufficiently higher in galvanic activity than steel to be effective as sacrificial anodes. (1) C Pressure Injection of Underwater Cracks When cracks expose the reinforcing steel to moisture, the corrosion process may begin. In saltwater environments, corrosion can occur quite rapidly. With the proper selection of a water-compatible adhesive (normally an epoxy resin), dormant cracks (cracks that are not moving) that are saturated with water can be repaired. The procedure can also repair other small voids such as delaminations or honeycombed areas near the concrete s surface. Within limits, pressure injection can be used against the hydraulic head, provided the injection pressure is adjusted upward to counteract the pressure of the hydraulic head. The material must displace the water as it is injected into the crack to ensure that the crack is properly sealed, resulting in a watertight, monolithic structural bond. (1) Epoxies must have certain characteristics to cure and bond the cracked concrete. Many adverse elements are present inside the concrete crack (e.g., water, contaminants carried by water, dissolved mineral salts, debris from the rusting reinforcing steel, etc.). The typical low surface temperature of concrete underwater makes many repair products unsuitable candidates because of their inability to cure properly. The epoxy injection resins for cracks are formulated for low viscosity, and they do not shrink appreciably. The surface wetability of epoxy resin is a major concern because the resin needs to displace all of the water in the crack, adhere to a wet concrete surface, and then cure in the wet environment. (1) The procedure involves cleaning the crack with a high-pressure water jet system and shaping the surface of the concrete directly above the crack so that it can be sealed with a grout. Using a hydraulic or pneumatic drill, holes are drilled to intersect the crack and then injection ports are installed in the holes. Subsequently, the surface of the crack is sealed with a grout material suitable for underwater use, such as cementitious or epoxy mortar. The purpose of the grout is to retain the adhesive as it is pumped into the crack. The adhesive is pressure-injected into the crack through the ports that are embedded in the grout at regular intervals. The injection sequence begins at the bottom and advances upward. The injection moves up when the adhesive reaches a port and begins to flow out of it. Epoxy resin is mixed either before or after pumping begins. Cracks varying in width from cm (0.002 inch) to 0.6 cm (0.25 inch) have been successfully injected. Epoxy pressure injection has become regarded by the maintenance communities of a number of state DOTs as a cost-effective method to bond and seal cracked structural members under the water line. However, some precautions must be considered before using this repair method. (1) Contaminants growing inside the crack, especially those found underwater, can reduce the ability to weld cracks. Corrosion debris can reduce the effectiveness of pressure injection. Time and patience is required for a successful injection repair. An injection repair is a labor-intensive process. (As the temperature drops below 10 C (50 F), it becomes more difficult to pump epoxy resins into fine cracks.)

243 A diver experienced in the injection process and in the formulation of an epoxy resin is very important for high-quality work. (1) C Concrete Repair Underwater While the methods and materials for underwater concrete repair are nearly identical to those used above the water line, the adverse working environment creates special considerations. (1) C Concrete Removal Unless CP is used, the salt-contaminated concrete and rust must be removed from contact with the existing reinforcing steel to ensure that the corrosion damage will not continue. Concrete removal underwater is labor-intensive, difficult, and expensive work to perform. Consequently, structural jackets or auxiliary members should be evaluated as alternatives to removing concrete. Concrete can be removed with high-pressure water jets or with chipping hammers. Construction joints between old and new concrete should be saw cut prior to removing concrete, preventing feather edges at the joint. Hydraulic or pneumatic-powered concrete saws and chipping hammers may be adapted for use underwater. Mechanical grinders are also available for cleaning concrete surfaces. Surface preparation is required after concrete is removed and before making the repair. High-pressure water jets, abrasive blasting, or mechanical scrubbers can remove all loose and fractured concrete, marine organisms, and silt. Where the water is heavily laden with contaminants, repairs should be made on the day of final surface preparation. This will reduce accumulation of new surface deposits. (1) C Forms Forming materials and forming techniques have been developed specifically for application underwater. Forms are used to encase damaged concrete areas or masonry substructure units. Some pile-jacketing forms are proprietary and marketed as a repair package. The shape, size, and location of the damaged element will often dictate the forming system to be used for the repairs. In work underwater, the cost of the forms is less of an economic factor than the ease of installation and the suitability to the repair. Commonly available polyethylene drainage pipe is also used as a form. In some repairs, it may be more economical and quicker to encase all piling with a jacketing wall in one concrete placement process rather than trying to jacket individual piles. Fabric forms are relatively inexpensive and can be easily handled by a diver. With a fabric form, the final repair may appear irregular in thickness, but shape and texture are not concerns for underwater repairs. Fabric forms are available with zippers for ease of installation, with spouts for pumping the repair material into the form, and with pressure seals to hold the material inside the form. (1) C The Mix Anti-washout admixtures are used to: (1) minimize washing the fine aggregate and the cement out of the concrete while it is in contact with flowing water, (2) prevent segregation of the concrete, (3) reduce bleeding, (4) decrease migration of moisture within the concrete mix, and (5) inhibit water entrainment as the concrete is placed. These admixtures tend to make the concrete sticky. A waterreducing agent or a high-range water reducer may be necessary to maintain proper concrete slump. Slump values up to 20 cm (8 inches) are possible. Experience has

244 indicated that concrete mixes containing anti-washout admixtures with either silica fume or fly ash can produce higher quality repairs at equal or lower cost than similar concretes containing higher silica fume content or high cement content but not incorporating anti-washout admixtures. (1) C Under water Placement When a limited amount of water is needed for cement hydration and for concrete workability, additional water will damage the mix. As the ratio of water to cement increases, the permeability of the concrete increases and the strength decreases. If conventional concrete is dumped into water with no confinement as it falls through the water, it will lose fine particles, become segregated, or be completely dispersed, depending upon the distance of the fall and the velocity of the water current. Saltwater mixed with the concrete will corrode the reinforcing steel. Special techniques are needed to protect the concrete as it placed underwater. (1) C Bagged Concrete Concrete placed in bags can be used to repair deteriorated or damaged portions of concrete or masonry substructure elements underwater. Conventional bagged concrete repairs are made with small fabric bags prefilled with dry concrete mix (often only sand and cement is used) and anchored together to form the exterior of the repair. The bags are small enough to be placed in position by hand. The interior portion of the repair is then filled with tremie concrete or dewatered by small crews. This requires minimal skill and equipment. This process is often used when the water is so shallow that special underwater diving equipment is not required. Bagged concrete application was expanded when it became possible to take advantage of the durability and high strength of synthetic fibers to produce forms for casting concrete underwater. These bags possess sufficient durability to be used in marine environments exposed to cyclic changes (tidal flows) and provide abrasion resistance (to floating debris and to particulates carried in the water flow). The properties of fabric-formed concrete are essentially the same as those expected from concrete cast in conventional rigid forms, with one exception: The water-cement ratio of the concrete can be quite low at the surface since the permeable fabric allows water to bleed through the bags. (1) C Prepackaged Aggregate Concrete After the repair area is properly prepared and the forms are in place, graded aggregate is placed in the form. A cement-sand grout is then injected into the area containing the aggregate, displacing the water and filling the voids between the aggregate particles. This method is particularly effective for underwater repairs where it would be difficult to place premixed concrete because of forming restrictions. Generally, an expansive grout with a fairly high water-cement ratio is used to provide fluidity. When anti-washout admixtures are added to the grout, the forms do not have to be as watertight as is otherwise needed. (1) C Tremie Concrete Tremie concrete is placed underwater by gravity flow through a pipe called a tremie. The underwater portion of the pipe is kept full of plastic concrete at all times during placement of the total quantity of concrete. Concrete placement starts at the lowest point and displaces the water as it fills the area. A mound of concrete is built up at the beginning of the placement. To seal the tremie, the

245 bottom of the tremie must stay embedded in this mound throughout the placement. The concrete is forced into the occupied area by the force of gravity from the weight of concrete in the tremie. The thickness of the placement is limited to the depth of the mound of concrete. Tremie concrete is best suited for larger volume repairs where the tremie will not need to be relocated frequently or for deep placements where it would be impractical to pump the concrete. The method of placing concrete with a tremie is simple and requires few pieces of equipment, minimizing potential malfunctions. Thus, it is one of the most common methods used to place concrete underwater. (1) C Pumped Concrete Pumped concrete is placed underwater using the same equipment that is used to place concrete above water. The placement process is similar to the process of using a tremie except that the end of the pump line does not need to be in the concrete as with a tremie. A direct transfer of the concrete is provided, and the pump forces the concrete through the supply line. The placement of concrete must start at the bottom of the area and the hose or pipe must stay submerged in the fresh concrete during placement. However, the pipe does not need to be lifted as much as with a tremie. A handle on the end of the pipe or hose will help the diver position it. (1) C Free-Dump Concrete Anti-washout concrete admixtures have been developed to minimize loss of fine aggregate and reduce segregation when the product is placed underwater. This admixture makes the concrete more cohesive yet sufficiently flowable for placement. However, the concrete mix loses some of its normal self-leveling properties and tends to stick to equipment. It is not clear that free-dumping concrete underwater with admixtures to improve placement quality is as effective as other more controlled methods of placement. Therefore, this method should be used with caution. It may be appropriate when high-quality concrete is not a primary consideration, where there is low water current velocity, and where the free-drop distance is limited to about 1 meter (about 3 feet). (1) C Hand-Placed Concrete Hand-placed concrete is mortar or concrete that the diver places by hand and then packs or rams for consolidation. This method is best suited for isolated repair sites. Use of accelerators, anti-washout admixtures, and a low water-cement ratio is recommended. The method is best suited for deep, narrow cavities. The concrete can be delivered to the diver by a bucket on a rope conveyor assembly. It can also be dropped to him in baseball-sized quantities through a pipe with holes cut in the sides to allow displaced water to escape, easing descent of the concrete. Small quantities needed for patching can also be delivered to the diver in plastic bags. (1)

246 C.3 Other Bridge Related Work C.3.1 Culverts C C C C Repair Headwall/Wings Replace Headwall/Wings Repair or Replace Culvert Apron/Cutoff Wall Repair Culvert Barrel C.3.2 Erosion Control C Repair or Construct Streambed Paving C Paving Metal Bottom Pipes, Arches and Culverts C Dumped Riprap (Rock Protection) C Gabion Baskets (Rock Protection) C Repair or Construct Stream Deflector C Excavate and Fill Scour Hole C Repair of Scour Holes Beneath Concrete Footings C Removal of Vegetation/Debris C Removal Depositation C.3.3 Construct Temporary C Construct Temporary Support Bent C Construct Temporary Pipes C Construct Temporary Bridge

247 C.3. Other Bridge Related Work Work not performed on superstructure or substructure elements but still considered bridge work is work performed on: Culverts Erosion Control Construct Temporary Structures C.3.1. Culvert C Repair Headwall/Wings This repair is for work on the full length and depth of masonry and concrete headwalls and wingwalls of culverts identified by the Department as having the minimum dimensions to qualify as being considered a bridge in the Bridge Management System. (8) This repair involves repairing or replacing all or portions of concrete or masonry headwalls or wingwalls. The work can include, but is not limited to, installing sheeting, when necessary, and excavating material retained by or protecting the headwall or wingwall; removing deterio-rated or damaged concrete, reinforcing steel; constructing forms; placing concrete; replacing and pointing masonry elements; pressure grouting masonry; epoxy pressure grouting; and replacing excavated material. When roadway embankment or protective material such as riprap is excavated to gain access to the work, it should be replaced in conformance with standard highway maintenance procedures. (8) Equipment Concrete Mixer Gradall or Backhoe Material Concrete Mix Reinforcing Steel Formwork Siltation Devices (8) Procedure 1. Install siltation devices. 2. Excavate as required to set dowels and forms. 3. Remove all fractured or deteriorated concrete to sound concrete by chipping, and blast clean to remove laitances. 4. Drill and set form anchor bolts and dowels. Dowels are to be placed a minimum of 9 in. Into sound concrete and set with nonshrink grout, or approved adhesive, 18 in. on center, front and back. 5. Cross-lace bars and set forms. 6. Just prior to placing concrete, apply epoxy bonding agent to all existing concrete that is to come into contact with new concrete. 7. Cure concrete until concrete has developed sufficient strength to resist the imposed lateral pressures before backfilling with granular material. 8. Remove siltation devices. (8)

248 C Replace Headwall/Wings Equipment Concrete Mixer Gradall or Backhoe (8) Material Concrete Mix Reinforcing Steel Riprap Siltation Devices (8) Procedure 1. Install siltation devices. 2. Install sluices or other water diversion devices. 3. Remove existing wingwalls and/or headwall and excavate to sound material. 4. Clean all concrete that is come in contact with new concrete. Chip and blast-clean existing concrete to remove any unsound material and laitance. 5. Drill holes and set dowels with non-shrink grout or approved adhesive. 6. Prior to placing concrete, provide for adequately reinforced weep holes. 7. Set forms and reinforcing steel and place concrete. Just prior to placing concrete, apply epoxy bonding compound to all existing cleaned concrete that is to come in contact with fresh new concrete. 8. Backfill adequately cured concrete, wingwalls. Suitable filter shall be provided for weep holes. 9. Provide scour protection for wings. 10. Remove siltation devices. 11. Remove sluices or other water diversion devices. (8) C Repair or Replace Culvert Apron/Cutoff Wall Work can be most efficiently performed during periods of low water which are most likely to occur during late summer or early fall. (8) This procedure is for work on the entire width and length of existing masonry and concrete aprons and cutoff walls of culverts identified by the Department as having the minimum dimensions to qualify as being considered a bridge identified in the Bridge Management System. This work includes repairing and replacing all or portions of existing culvert cement concrete or masonry aprons and cutoff walls. The work can include, but it\s not limited to, constructing sluices or providing other means to conduct water through the structure and to protect the work and freshly placed concrete from flowing water; driving sheeting; removing deteriorated masonry units, mortar concrete, and reinforcing steel; excavating

249 material to the required dimensions; placing and compacting suitable base material; drilling and install-ing dowels; constructing forms; placing and tying reinforcing steel; placing concrete; placing and pointing masonry units; and backfilling. (8) Equipment Backhoe Drill (8) Material Concrete Reinforcing Steel Epoxy Dowels Base Material Backfill Sluice Material Siltation Devices (8) Procedure 1. Install siltation devices. 2. Construct sluices or other devices to divert stream. 3. Remove deteriorated masonry. 4. Excavate unsuitable material. 5. Place and compact base material. 6. Drill holes and set dowels with non-shrink grout or approved adhesive. 7. Construct formwork. 8. Place reinforcing steel. 9. Place concrete. Just prior to placing concrete, apply epoxy bonding agent to all existing concrete that is come into contact with new concrete. 10. Remove formwork. 11. Remove sluices and siltation devices. 12. Grade Streambed. (8) C Repair Culvert Barrel Work can be most efficiently performed during periods of low water which are most likely to occur during late summer or early fall. (8) This repair is for the full length and width of masonry and concrete culvert barrels of culverts identified by the Department as having the minimum dimensions to qualify as being considered a bridge identified in the Bridge Management System. This work may involve repairing all or portions of concrete or masonry culvert barrel. The work can include, but is not limited to, constructing sluices or providing other means to control water flow through the culvert so the work can be accomplished; driving sheeting; excavating material; removing deteriorated concrete, reinforcing steel or

250 masonry; epoxy pressure grouting; and replacing excavated material. When roadway embankment or pavement is excavated to gain access to the work, it should be replaced in conformance with standard highway maintenance procedures. (8) Equipment Backhoe Drill Pressure Injection Equip (8) Material Concrete Reinforcing Steel Epoxy Cement Dowels Backfill Sluice Material Siltation Devices Grout (8) Procedure 1. Install siltation devices. 2. Construct sluices or other devices to divert stream. 3. Remove deteriorated masonry. 4. Drill holes and set dowels with non-shrink grout or approved adhesive. 5. Construct formwork. 6. Place reinforcing steel. 7. Place concrete. Just prior to placing concrete, apply epoxy bonding agent to all existing concrete that is to come in contact with new concrete. 8. Replace, repair and point masonry elements. 9. Pressure inject any cracks with epoxy cement. 10. Remove sluices. 11. Remove siltation devices. 12. Backfill, if necessary. (8)

251 C.3.2. Erosion Control C Repair or Construct Streambed Paving This repair is performed based on need as indicated by bridge inspections and/or changes in stream flow or conditions that increase the potential for scour problems. Work can be most efficiently performed during periods of low water, which are most likely to occur during later summer and early fall. (8) This work is performed on the entire width and breath of existing paved streambed areas or areas indicated on plans for new streambed paving, plus sufficient additional space to allow for required excavation and for the construction of sluices or other means to conduct water through the structure during the paving operation. (8) This work involves repairing existing areas of cement concrete streambed paving or constructing new cement concrete streambed paving in accordance with plans prepared for the work. The work can include, but is not limited to, constructing sluices or installing sheeting or providing other means to conduct water through the structure and to protect the work area and freshly placed concrete from flowing water; removing deteriorated concrete, reinforcing steel and unsuitable material below the bottom of the paving; excavating material to the required dimensions; placing and compacting suitable base material; drilling and grouting dowels; constructing forms; placing and tying reinforcing steel; placing concrete; saw cutting concrete; and placing preformed joint filler. When protective material such as riprap is excavated to gain access to the work, it should be replaced in conformance with work descriptions in appropriate activities. (8) Equipment Backhoe or Gradall Drill Concrete Saw (8) Material Concrete Siltation Devices Backfill Dowels Reinforcing Steel Joint Filler Material (8) Procedure 1. Divert upstream flow with a sump or dam and pump water via conduit through the culvert. 2. Clean out debris and silt as required. 3. Maintain existing water surface profile. 4. Construct reinforced paving to a depth of 12", as needed, and place riprap at the outlet end as needed. Do not finish off concrete, leave the surface rough to allow turbulent flows and depositions. Depth of water through the culvert after restoration of flow will approximate the natural stream conditions

252 5. Allow concrete to harden (enough to walk on), flush concrete with stream water and pump upland until ph level is below 9. Upland discharge will preclude any reentry of water into the stream and any erosion effects. 6. Remove sump or dams and restore stream flow. Seed and mulch as required. (8) C Paving Metal Bottom Pipes, Arches and Culverts Based on need as indicated by bridge inspections and/or changes in stream flow or conditions that increase the potential for scour problems. Work can be most efficiently performed during periods of low water, which are most likely to occur during later summer and early fall. This work is on the entire width and breath of existing paved streambed areas or areas indicated on plans for new streambed paving, plus sufficient additional space to allow for required excavation and for the construction of sluices or other means to conduct water through the structure during the paving operation. (8) This procedure involves repairing existing areas of cement concrete streambed paving or constructing new cement concrete streambed paving in accordance with plans prepared for the work. The work can include, but is not limited to, constructing sluices or installing sheeting or providing other means to conduct water through the structure and to protect the work area and freshly placed concrete from flowing water; removing deteriorated concrete, reinforcing steel and unsuitable material below the bottom of the paving; excavating material to the required dimensions; placing and compacting suitable base material; drilling and grouting dowels; constructing forms; placing and tying reinforcing steel; placing concrete; saw cutting concrete; and placing preformed joint filler. (8) Equipment Backhoe or Gradall Drill Concrete Saw (8) Material Concrete Siltation Devices Backfill Dowels Reinforcing Steel Joint Filler Material (8) Procedure 1. Divert upstream flow with a sump or dam and pump water via conduit through the culvert. 2. Clean out debris and silt as required. 3. Construct reinforced paving to a depth of 6" to 8", as needed, and place riprap at the outlet end as needed. Do not finish off concrete, leave the surface rough to allow turbulent flows and depositions. Depth of water through the culvert after restoration of flow will approximate the natural stream conditions

253 4. Allow concrete to harden (enough to walk on), flush concrete with stream water and pump upland until ph level is below 9. Upland discharge will preclude any reentry of water into the stream and any erosion effects. 5. Remove sump or dams and restore stream flow. Seed and mulch as required. (8) C Dumped Riprap (Rock Protection) Based on need as indicated by bridge inspections and/orchanges in stream flow or conditions that increase the potential for scour problems. The minimum size of stone in rock protection when gabions are not used should be based on a maximum anticipated velocity of water. (8) This procedure is for all areas at and adjacent to bridge substructure units that are subject to scour and require rock protection and involves restoring existing rock protection by relocating existing rock and placing additional rock as required, or placing new rock protection at and adjacent to bridge substructure units. The work can include, but is not limited to, removing dislocated existing rock; preparing surface by excavating unsuitable material, backfilling, placing material, and grading surface; placing geotextiles; placing gabion baskets; placing rock either directly on geotextiles and prepared surface or in gabion baskets; and wiring tops on gabion baskets. (8) Equipment Front End Loader (8) Material Riprap (8) Procedure 1. Install siltation devices. 2. Prepare foundation by removing unsuitable base material if required. 3. Backfill with suitable base material if required. 4. Place geotextiles if appropriate. 5. Place Riprap of the size specified by dumping to depth specified. 6. Remove siltation devices. (8) C Gabion Baskets (Rock Protection) Equipment Excavation Equip (8) Material Aggregates or Large Rocks Siltation Screens Backfill Gabions Geotextile Fabric (8) Procedure 1. Install siltation devices

254 2. Excavate and remove all unsuitable material below the face of the wingwall to be retained or stabilized. 3. As required, replace unsuitable material with an acceptable granular material and thoroughly compact the entire foundation to a firm, even surface. 4. Place specified geotextile fabric or place cement concrete pad. 5. Assemble, bind, join, and place gabions. 6. Fill Type A gabions by hand, or with small power equipment, using specified aggregate. 7. As specified, secure lid to sides, ends, and diaphragms using connecting wire. 8. Place the specified large rock buttress at a one-to-one slope. 9. Remove siltation devices. (8) C Repair or Construct Stream Deflector Based on need as indicated by bridge inspections and/or hydraulic evaluations. Work can be most efficiently performed during periods of low water which are most likely to occur during later summer or early fall. Authorization from environmental agencies may be required before the work has begun. (8) This procedure is for areas of stream banks adjacent to bridges at existing stream deflectors or as shown on the plan for new stream deflectors. (8) This work involves repairing existing or constructing new stream deflectors. The work can include, but is not limited to, removing displaced existing embankment protection material; excavating unsuitable material; driving sheet piling; and placing embankment protection materials. (8) Equipment Backhoe Pile Driver Crane (8) Material Embankment Protection Material Sheeting Geotextile Fabric (8) Procedure 1. Install siltation devices. 2. Remove displaced existing embankment protection material and dispose of properly. 3. Excavate unsuitable material and dispose of properly. 4. Drive piling as shown on plans. 5. Place and compact suitable material. 6. Place geotechnical fabric. 7. Place embankment protection material. 8. Remove siltation devices. (8)

255 Figure C. 184 C Excavate and Fill Scour Hole Based on need as indicated by bridge inspections. Inspections in addition to regularly scheduled inspections may be appropriate following unusually high water, particularly in areas where scourable material is present and where scour holes previously occurred. Authorization from environmental agencies may be required before the work is begun. (8) This procedure is for all areas of stream beds at and adjacent to substructure units where scour holes are present and cause potential hazard to a bridge. (8) The work involves filling scour holes at and adjacent to substructure units with scour resistant material. The work can include, but is not limited to, excavation of silt or other highly scourable material naturally deposited in scour holes, removal of debris that is a contributing cause to the formation of a scour hole and the placing of heavy rock around a pier to prevent a scour hole from becoming a hazard to a pier. (8) Equipment Excavation Equip (8) Material Scour Resistant Material Siltation Devices (8) Procedure 1. Install siltation devices. 2. Excavate highly scourable material and dispose of properly. 3. Place scour resistant material. 4. Remove siltation devices. (8)

256 C Repair of Scour Holes Beneath Concrete Footings This repair is for when soil etc., has scoured out from beneath abutment or pier footings. Procedure 1. Bolt a row of sheet piling in front of the footing with 16mm diameter, 300 mm long bolts. 2. Place No.4 bars at 150 mm centers (or equal mesh) each way as shown below. 3. Fill the cavity beneath the footing and between the sheet piling and the footing with concrete. 4. Fill remaining space with grout or pumpcrete after the concrete has cured a minimum of 1 day. Figure C. 185 Abutment Plan Figure C

257 C Removal of Vegetation/Debris Debris is likely to collect at substructure units during a period of high water to help reduce scour problems. Authorization from environmental agencies may be required before the work is begun, and this authorization is especially important when standing vegetation is to be removed. (8) Areas around substructure units where debris has collected, and areas of stream beds and banks adjacent to the structure under State control where standing vegetation impedes stream flow or might become dislodged and cause hazardous conditions in the future. (8) Removing and disposing of vegetation and debris which is growing or has collected in the work area. The work can include, but is not limited to, removing debris collected around substructure units by manual and/or mechanically assisted means; cutting down and removing growing vegetation; loading material in truck; and disposing of material at an approved dumping location. (8) Equipment Chain Saw Bush Ax Backhoe Front End Loader Winch or Pulling (8) Material None (8) Procedure 1. Remove debris collected around substructure. 2. Remove vegetation from stream banks and the streambed. 3. Dispose of debris and vegetation properly. (8) C Remove Depositation Material deposited during periods of high water especially if the material is deposited in a manner that will change the direction or velocity of the flow increasing the possibility of scour. Authorization from environmental agencies may be required, particularly when it is necessary to place equipment such as bulldozers in the stream. (8) Streambeds and banks at and adjacent to bridge substructure units where excess material has been deposited that reduces the hydraulic efficiency of the structure. (8) Excavating and disposing of soil, clay silt, sand, gravel or rock that has been deposited in streambeds and on stream banks at and adjacent to bridge substructure units. The work can include, but is not limited to, excavating deposited material; grading streambeds and banks; loading material in trucks; and disposing of material at approved dumping locations. If the deposition of material has been initiated because of a collection of debris or vegetation, the debris and vegetation should be removed. (8) Equipment Excavation Equip (8) Material Silt Barrier (8)

258 Procedure 1. Install siltation devices. 2. Excavate deposition and dispose of properly. 3. Grade streambed and banks. 4. Remove siltation devices. (8) C.3.3. Construct Temporary C Construct Temporary Support Bent All areas shown on plans as required for installation of temporary support bents, placing of equipment, access to the work, and portions of existing superstructures or substructures at end adjacent to the bents. (8) Constructing temporary bents to support superstructures or substructures as indicated on the plans provided by the Department for the work. The work can include, but is not limited to, driving piles; excavating material; installing structural steel; cutting, drilling and erecting timber members; and modifying existing superstructures or substructures to accept attachments to the bents or loads imposed by them. (8) Work under this activity is intended to temporarily support or strengthen structures to eliminate or raise posting limits, to allow the passage of overweight permit vehicles, to protect the bridge and the public using it pending structure rehabilitation or replacement, or for a similar specific primary purpose. (8) Equipment Crane Pile Driver with Jack (8) Material Temporary Bent Blocking Shims (8) Procedure 1. Modify structure to accept new load distribution if necessary. 2. Prepare foundation for temporary bent or drive piles depending on bent type selected. 3. Construct bent. 4. Jack superstructure. 5. Block and shim as necessary. 6. Remove jacks and check for distress. (8)

259 Figure C. 187 Alternate No 1 Figure C. 188 Alternate No 2 Figure C. 189 Alternate No

260 Figure C. 190 Alternate No 4 Figure C. 191 Alternate No

261 Figure C. 192 Alternate No 6 Figure C. 193 Alternate No

262 Figure C. 194 Alternate No 8 C Construct Temporary Pipes Pipes can be installed most conveniently during periods of low water which normally occur in the late summer and early fall. (8) All areas shown on plans as necessary for the installation of pipes and the embankments in which they are placed. (8) Placing of temporary pipes in temporary embankments to divert traffic from an existing structure (so-called go-arounds_) or placing of temporary pipes in an existing embankment to divert water from an existing structure. The work can include, but is not limited to, excavating material; placing pipe; bolting structural plate pipe sections together; installing bands, or other means to connect pipe sections; placing and compacting embankment material; placing embankment protection material; and installing guide rail. Any necessary earthwork and other associated work should be done in accordance with the requirements of the appropriate highway maintenance activities, but should be charged to this activity. Work under this activity is intended to raise posting limits, to protect a bridge and the public using it pending structure rehabilitation or replacement, or for a similar primary purpose. (8) Equipment Backhoe Front end loader

263 Grader Paver Post Driver Crane (8) Material Fill Material Bedding Material Bridge Components Pavements Guardrail (8) Procedure 1. Install siltation devices. 2. Construct approach fills. 3. Excavate, if necessary. 4. Prepare the bedding material. 5. Place pavement. 6. Install Guiderail. (8) C Construct Temporary Bridge All areas shown on plans as necessary for the erection of a temporary bridge and its approaches. (8) Constructing temporary bridges and approaches in accordance with plans furnished by the Department. The work can include, but is not limited to, excavating material; driving piles; installing sheeting or other devices to control the flow of water; constructing forms; placing reinforcing steel; placing concrete; cutting, drilling and erecting timber members; erecting structural steel members; and placing embankments and performing associated work. Any necessary earthwork and other associated work should be done in accordance with the requirements of the appropriate highway maintenance activities, but should be charged to this activity. (8) Equipment Concrete Mixer Air Compressor with Jack Hammer appropriate to depth to be removed (8) Material Reinforced Steel Concrete (8) Procedure 1. Install siltation devices. 2. Construct approach fills. 3. Excavate, drive piles, place caps, install bulkheads, set beams, place deck, and attach rails as necessary to construct temporary bridge. 4. Backfill and finish grading approaches. 5. Place pavement. 6. Install Guiderail (8)

264 REFRENCES (1) Bridge Maintenance and Management AASHTO (2) PennDot Maintenance Manual (3) Fundamentals Of Bridge Maintenance and Inspection. New York State Department of Transportation (4) Bridge Inspection, Maintenance, and Repair, Dept of the Army and Air Force (5) Preventive Maintenance/Repair Guidelines for Bridges and Culverts. Ohio DOT. (6) Repair Manual for Concrete Bridge Elements, Alberta Infrastructure and Transportation (7) Repair of Bridge Structural Steel Elements Manual. Alberta Infrastructure and Transportation (8) Procedures and Standards for Bridge Maintenance. Pennsylvania Department of Transportation. (9) Maintenance Supervisor s Manual. Arkansas State Highway and Transportation Department (10) Bridge Maintenance Manual. MnDot. (11) Preventive Maintenance Guidelines for Bridges. Missouri Department of Transportation. (12) Deaveer, R., A.-H. Zureick, and B. Summers. Repair with high-performance materials make bridges stronger, last longer. TR NEWS 226, pp Washington, D.C.: Transportation Research Board, May-June (13) Weyers, R. E., J. Zemajtis, and R. O. Drumm. Service lives of concrete sealers. Transportation Research Record 1490, pp Washington, D.C.: Transportation Research Board,