STRENGTHENING OF RC BRIDGE WITH MECHANICALLY FASTENED-FRP FRP STRIPS

Transcription

1 May 5 th 4 STRENGTHENING OF RC BRIDGE WITH MECHANICALLY FASTENED-FRP FRP STRIPS Andrea Rizzo (Graduate Research Assistants) Dr. Nestore Galati (Research Engineer) Dr. A. Nanni (Faculty Advisors) Meramec Regional Planning Commission DELTA Authority Objectives Upgrade the existing flexural capacity of bridge structures with mechanically fastened FRP laminates. Features: rapid installation; simple procedure; and, cost savings Non Destructive Tests for the bridge 1335 in Phelps County (3) Bridge 1335 in Phelps County (4) before and after the strengthening Procedure FRPs are Very Light and Easy to Handle FRP Preparation (cutting of the FRP to the design length and drilling of the holes according to the specifications) Surface Preparation (removal of sizeable protrusions such as form lines) Positioning of the CFRP Laminates Drilling of the Concrete Injection of Epoxy After Cleaning the Holes Placement of Studs in the Holes Fastening of the Bolts Bridge After Installation

2 In-Situ Diagnostic Cyclic Load Testing Paolo Casadei, Ph.D. Dr. A. Nanni (Faculty Advisor) NSF Industry/University Cooperative Research Center Load (lbf) Load (lbf) May 7-8 th 4 To assess a new protocol for load testing of RC/PC structures that allows to rate the structure based on the test-load reached during the load test, for which the structure has failed one of the three acceptance criteria, real time during the test Typical Load-vs-Time Plots Dead Load of Truss + Engagement : :4 4:48 7:1 9:36 1: 14:4 16:48 19:1 1:36 : Service level 4 hour load Test Cumulative Time (H:m) Cyclic load Test Load step Dead Load of Truss + Engagement : :14 :8 :43 :57 1:1 1:6 1:4 Cumulative Time (H:m) Load Cycle Background: In-situ Diagnostic Cyclic Load Test is a key procedure for structure evaluation. Cyclic In- Situ Load Testing, recently published in the ACI 437R-3 document takes a similar approach as the 4 hr load test described in ACI-318 (ch.), but uses cyclic instead of static loading, measures the structure response real time, and assesses its behavior through 3 acceptance criteria. This approach allows to rate the structure at the site by implementing these three parameters in the software that collects the data by flagging one of them when the reference values are not respected. Repeatability > 95% Permanency < 1% Deviation from Linearity < 5% The Orange Box Data Acquisition System R Typical Test Set-Up Steel Section Steel Plate R Steel Joists Hydraulic Jack Plywood Load Cell High Strength Steel Bar Reaction Beam Tested Slab Anticipated Benefits Validation of the Cyclic Load Test procedure, recently published in the ACI437R-3 document. Give more confidence in the owner of the structure about the real performance of the member under questioning, without permanently damaging it. Load-Rating of the structural member. Real-Time assessment of the structure investigated. R R

3 Secondary Reinforcement for FRP Reinforced Concrete Daniel Koenigsfeld (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) NSF Industry/University Cooperative Research Center May 7 th, 4 To investigate the development of an empirical based secondary reinforcement ratio which controls shrinkage and temperature cracks in applications such as bridge decks and other areas where durability is of concern. Background : GFRP secondary reinforcement ratio based on material stiffness comparison No experimental data available In most applications, Secondary Reinf. > Primary Reinf. Considered excessive by many experts Test Program: Three Phase Study: Phase I Early-age tensile test subjected to environmental conditions Phase II Later-age tensile test Phase III Cracks control of panels tested in flexure. To investigate possible standard test methods for secondary reinforcement that includes boundary restraint Phase I Environmental Chamber Restraint Load (lb) Avg. Crack Width (in) -#3 Steel -#3 GFRP 3-#3 GFRP 4-#3 GFRP Phase I Test Setup Phase I Crack Width vs. Restraint Load

4 Secondary Reinforcement for FRP Reinforced Concrete Daniel Koenigsfeld (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) NSF Industry/University Cooperative Research Center May 7 th, 4 Phase II Test Setup Phase III Test Setup Conclusions: Three times more GFRP is required to produce similar crack control characteristics when subjected to similar axial restraint loads at early-age. At later-age, steel is 1.3 times more efficient (load/area) at crack control than GFRP reinforcement. In flexure, twice as much GFRP is required to produce similar crack control as steel. Two and half time more GFRP yields similar mid-span deflection characteristics as steel when subjected to flexure. Tensile Load (lb) Crack Area (in ) 4-#3 Steel -#3 GFRP 3-#3 GFRP 4-#3 GFRP -#4 Steel -#4 GFRP 3-#4 GFRP 4-#4 GFRP Phase II Tensile Load vs. Crack Area Load (lb) Crack Area (in ) Steel (ρ=.) GFRP (ρ=.37) GFRP (ρ=.4) GFRP (ρ=.56) Phase III Load vs. Crack Area

5 Evaluation of the In-Service Performance of Bridge Decks Built with Fiber Reinforced Polymer (FRP) Composite System U. Deza (Graduate Research Assistant) Dr. Antonio Nanni (Faculty Advisor) University Transportation Center May 7 th -8 th, 4 Analytical Models Comparison between Field Test Results and Analytical Models aid to understanding the behavior of the structure and ensure appropriate Load Rating of the bridge decks built with FRP materials. D/ P (min/kip) WALTERS ST. BRIDGE FINITE ELEMENT RESULTS COMPARISSON AT THE FIST YEAR Field Test Results SAP Analythical Results: Solid Slab (uncracked) 1 Analytical Results: Hinge connection (uncracked) 34.in Objectives Monitor the performance of bridge decks built with FRP materials over a three-year period. Evaluated parameters include: Control of Deflections in service Assessment of Stiffness Degradation Load Rating through Load Testing Load Factor Distribution between Panels. Background Deterioration of bridges has motivated the use of FRP technology in two aging bridges in the City of Saint James. In, deteriorated concrete decks were replaced by decks built with FRP materials. Non Destructive Load Tests have been conducted over a period of three years to monitor their behavior. Walters St FRP-RC Bridge Saint Francis St GFRP Honey Combo Panel Deck Bridge St James, MO 1 in G-FRP BARS Top reinforcement and Stirrups C-FRP BARS Bottom Reinforment Evaluation of Deflection-Load over Time Field evaluation shows that the FRP bridge decks exhibit minimal stiffness degradation and same structural response under similar loading. Anticipated Benefits Motivate and create confidence in the use of both technologies in the competitive standard of short-span bridge market. D / P (min/kip. 1 6 ) WALTERS ST. BRIDGE FIELD TEST RESULTS Lateral location of the Truck Wheel (in) at Middle Span FRP RC Panels D / P (min/kip. 1 6 ) 5 1 SAINT FRANCIS ST. BRIDGE FIELD TEST RESULTS Lateral location of the Truck Wheel (in) at Middle Span GFRP Honey Combo Panels Data Acquisition System LVDT - Strands

6 Seismic Evaluation of Bent Cap/Column Joints in Missouri N. Ereckson (Graduate Research Assistant) Dr. P.F. Silva and Dr. G. Chen (Faculty Advisors) FHWA, MoDOT, ADOT, UTC 1) Investigate the failure of typical bridge bents in the central United States ) Propose a retrofit scheme using fiber reinforced polymers (FRP) Background : Despite the fact that portions of the central United States are within zones of potential seismic activity, a large number of highway bridges in this region are prone to experience damage in the event of an earthquake. Prototype Current Design Deficiencies 1. Inadequate Column/Cap Beam/Joint Shear Reinforcement. Inadequate Cap Beam Flexural Reinforcement Potential for Plastic Hinging in the Cap Beam Laboratory Test Model Testing 1) Unit 1 Test to shear failure of the column Strengthen the column using CFRP Test to shear failure of the joint Retrofit the area of the connection using CFRP Test to ultimate Unit Strengthen fully Test to ultimate Main Conclusions 1. Column capacity was enhanced w/ CFRP sheets. In joints retrofit should be conducted prior to onset of joint-shear failure Unit 1 Unit Unit 1 Damage Levels Unit At Ultimate Load (kip) Displacement (in) Units 1 & Load- Deformation Curve

7 Flexural Capacity of RC Beams Externally Bonded with SRP and SRG May 7 th & 8 th, 4 Determine the improvement in flexural capacity of RC members externally bonded with steel reinforced polymers (SRP) and steel reinforced grout (SRG), taking into account strain location response and a bond stress analysis. Erin Wobbe (Graduate Research Assistant) Dr. P.F. Silva (Faculty Advisors) NSF Industry/University Cooperative Research Center Structural Preservation Systems Background : It has been found that steel reinforced polymers and steel reinforced grout can provide a significant increase in flexural capacity of RC members. The advantages of this material is that it can be impregnated into a cementitious grout, providing not only a more traditional matrix, but a more fire resistant matrix as well. Test Set-up SRP/SRG Material Laboratory Strong Floor Load Cell 71.1 cm 3. cm 13.4 cm Loading Beam 44 x 3.5 cm Test Beam Support Plates Unit A-1N A-N B-1N B-N C-1N C-N D-1N D-N Test Matrix: External Reinf.. 3X 3X 3SX 3SX 3X 3X 3SX 3SX Adhesive Epoxy Resin Epoxy Resin Cement. Grout Cement. Grout Epoxy Resin Epoxy Resin Cement. Grout Cement. Grout No. Plies Internal Steel (in ) # Deflection (cm) # 3 1) Specimen Preparation ) A-1N Failure - Cover debonding in constant moment region 3) A-N Failure Cover debonding at edge of SRP sheet # 1 Shown to the right is the load deformation response for the experimental results of several of the tested specimens. This is in comparison with the theoretical predictions of the specimen. Load (Kip) A-1N Actual A-1N Theoretical A-N Actual A-N Theoretical B-N Actual B-N Theoretical..4.6 Deflection (in) Load (kn)

8 Monitoring of Bridge Structures: Cart for Bridge Inspection and Sensors Mounting Fabio Matta (Graduate Research Assistant, UMR) Max Vath (Rolla Technical Institute) Dr. Nestore Galati (Research Engineer, UMR) Dr. Antonio Nanni (V&M Jones professor of Civil Engineering, UMR) Strongwell, UMR-UTC, MoDOT, RTI Objective: All of the elements that directly affect performance of the bridge including the footing, substructure, deck, and superstructure must be periodically inspected or monitored. For bridges comprising of steel girders, in order to facilitate the inspection of the super structure and the installation of the sensors (i.e. fiber optics, strain gages, thermocouples, etc.), a modular cart supported between two adjacent girders was designed and constructed. The cart is composed by three demountable modules 4 ft (1. m) x 5 ft (1.5 m) allowing a total surface of 5 ft (1.5 m) x 1 ft (3.6 m) and a maximum number of six people on it. The total weight of the cart was contained to 47 lb (13 kg) thanks to the use of aluminum profiles for the frame and a lightweight structural fiberglass panels as flooring system. Schema of the Cart Installation of Fiber Optics Using the Cart on Bridge A6358

9 Deck Bridge Design with Internal FRP Reinforcement The construction of the bridge combined with laboratory testing, will demonstrate the feasibility using GFRP bars with internally posttensioned CFRP tendons. Raffaello Fico (Visiting Scholar, University of Naples) Dr. Nestore Galati (Research Engineer) Dr. Antonio Nanni (Faculty Advisor) FHWA-IBRC/Hughes Brothers Inc. Background: FRP composite materials are currently applied to existing construction. An area of primary interest is bridge decks where deflection control and shear capacity are of primary importance. New Bridge Cross Section FRP Reinforced Concrete Deck Existing Steel Reinforced Deck New Steel Concrete Sidewalk Specimens Preparation Prestressing System 4'-6" 19'-8" 1'-11" 6'-9" 39'-4" Benefits: Combination of post-tensioned and unstressed reinforcement increased the ultimate flexural and shear strengths as well as performance under serviceability load conditions. Laboratory Testing Load 1 Load Load [ kn ] Test Results Displacement [mm]

10 Integrated Structural Health Monitoring Using Fiber Optic Sensors s of Bridge A6358 Dr. Nestore Galati (Research Engineer) Dr. Filippo Bastianini (University of Naples- Italy) Dr. Antonio Nanni (V&M Jones professor of Civil Engineering) Yokogawa-Ando, UMR-UTC, MoDOT Background: A fully-distributed sensing technique using standard telecom fiber optics as fully-intrinsic sensors will be used in order to measure the strain along the girders of the bridge. This task will be accomplished by means of an AQ863 Brillouin Optical Time Domain Reflectometer (BOTDR). Even though this technology was developed for telecom cable testing and optical fiber quality control, it can also be used for strain and temperature monitoring in a variety of structural applications, bringing several advantages over more traditional measuring techniques. In addition, the fiber optics mounted over the bridge can also be used for health status monitoring by performing Brillouin analysis on periodical basis, or, if required, continuously. Fiber Optic Installation The scope of this project is the assessment of a High Performance Steel (HPS) bridge located at the Lake of the Ozarks in Miller County. The bridge numbers is A6358 and it is located on US Rt. 54/Osage River. Strain Distribution Along the Girders

11 Surface Roughness Effects on Bond Strength Jason Jeffries (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) National Science Foundation May 7 th, 4 Determine an optimum surface roughness for concrete accepting carbon fiber reinforced polymers (CFRP) sheets to allow for the most efficient stress transfer between the concrete surface and the CFRP sheet. Background : Bond between the substrate and FRP is crucial in the development of the stress transfer between them. This study is examining the effects of surface roughness as well as using different techniques for roughening the concrete surface UNIT I A Ranges: Average is Value Method: Two phases of study were introduced. Phase I examined the effectiveness of a rotary grinder to roughen the concrete surface. Phase II examined the effectiveness of water jet technology and created varying roughness levels and textures. Surface Roughness Made by Water-Jetting i A = 4.11 i A = i A = i A = 4.51 i A = 5.91 i A = 1.55 Phase I Phase II Roughness Measuring Equipment i A = 4.57 i A = 7.5 ICRI Standard Roughness Index i A = 9.3 Phase II Direct Shear Bond Test

12 Nondestructive Testing (NDT) of Dallas County Bridge May 7 th & 8 th, 4 1) Investigation of the long-term behavior and durability of CFRP and SRP strengthened RC bridge members. Research Topics: 1) Microwave, Ultrasonic, and Echo-Impact NDT of delaminations ) Surface roughness measurements 3) Fiber alignment measurements 4) Bond strength measurements 5) Strain measurements 6) Damage detection. M. Ekenel, A. Lopez, S. Vivian, J. Fonda, R. McDaniel, Dr. J. Myers, Dr. A. Nanni, Dr. R. Zoughi, Dr. G. Chen, Dr. N. Maerz, Dr. G. Galecki, Dr. S. Watkins, Dr. N. Galati, Dr. S. Kharkivskiy, Dr. V. Godinez MoDOT, UTC, RB C View of the Dallas County Bridge, MO Fiber Optic Installment for Strain Measurements Echo-Impact NDT of Delaminations Surface Roughness Measurements Fiber Alignment Measurements Acousto-Ultrasonic NDT of Delaminations Bond Str. Measurements by Pull-out Tests Damage Detection via Coaxial CrackSensors Microwave NDT of Delaminations

13 Stress Fatigue Behavior of RC Beams Strengthened with CFRP Sheets Under Severe Environmental Conditioning s max s min May 7 th, 4 Objectives 1.Evaluation of precracked RC beams under fatigue loading with/without CFRP strengthening and delaminations.investigation of aggressive environmental conditioning Mahmut Ekenel (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) Federal Highway Administration (FHwA) Background : In recent years, fiber reinforced polymers (FRP) have gained importance in rehabilitation works since they offer resistance to corrosion, high stiffness-toweight ratio and applicability to repair in the field with minimal disruption. However, the fatigue performance, especially under aggressive environmental conditions, still needs further investigation. Lab. Tests vcyclic Range: 33% & 63% of the ultimate moment capacity. vsustained load applied as 4% of the ultimate moment capacity. Description Stiffness Change CFRP sheet strengthening 1 CFRP plate strength.-epoxy 11 CFRP sheet strength.-anchor spikes 14 CFRP plate strength.-bolts 93 CFRP sheet strength.-4 env. cycles 93 CFRP sheet strength.-ext. conditions 8 CFRP sheet str.-delam.-4 env. cycles 79 CFRP sheet str.-delam.-ext. condition 77 CFRP sheet strength.-8 env. cycles 74 CFRP sheet str.-delam.-8 env. cycles 66 Sustained Load Test Set-up in Env. Chamber Exterior Exposure Anchor Spikes Stiffness (lbs/in) Stiffness vs Number of Cycles 1, 11, 1, 9, 8, 7, 6, CFRP - Anchor CFRP - Control CFRP - Env (4) CFRP - Env (4) Del CFRP - Env (8) CFRP - Env (8) Del CFRP - Ext. CFRP - Ext. Del CFRP - Plate Ep CFRP - Plate Bolts 5, 4, Fatigue Test Set-up Microwave NDE Inspection Mech. Anchorage Number of Cycles (Thousands)

14 May 7 th & 8 th 4 Stress (Mpa) # 1 y = 1115x Characterization of SRG and SRP (Steel Reinforced Grout /Polymer) 1X B-13 Stress Strain (Machine Head).%.5% 1.% 1.5%.%.5% 3.% 3.5% concrete block fully bonded and mechanically anchored end load cell Strain (mm/mm) hydraulic jack 1" Marta Matana (Graduate Research Assistant) Dr. Antonio Nanni (Faculty Advisor) CIES Background: Steel reinforced polymers and grouts are highly effective as external reinforcement for upgrade of concrete structures. Especially, use of cementituous grout to impregnate the steel cords will result in fire resistant composite material. # bonded length (4",8",1") concrete block test region # 3 1) Tensile characterization ) Bond performance (water jetted and laser profilometry characterized concrete surface) 3) Effective bond length 4) Tensile characterization of bent system 5) Impact testing - comparison study 6) Blast resistance - comparison study # 5 # 4 # 6 # 1 - Tensile testing # - Stress - strain curve of the specimen tested under tension # 3 - Set up for effective bond length characterization # 4 - Water jetting of concrete surface for bond performance testing # 5 - Test device for bent system testing # 6 - Impact testing

15 Device for prestressing FRP sheets and its application Piyong Yu (Graduate Research Assistant) Dr. P.F. Silva (Faculty Advisor) NSF Industry/University Cooperative Research Center May 7 th & 8 th, 4 1) Develop one mechanical device for prestressing FRP sheets ) Investigate the behavior of RC beams strengthened with prestressed FRP sheet Background : For reinforced concrete (RC) beams strengthened with externally bonded fiber reinforced polymer (FRP) sheet, higher portion of FRP sheet could be used after prestressing. Flexural capacity and serviceability of the strengthened RC beams may increase after prestressing of the FRP sheets. Nut Threaded rods Steel strip Loading region Removable plate Bearing Fixed plate Anchorage region CFRP sheet # 1 # 6 Anchorage region Loading region Testing Matrix: 1) Prestressing of FRP sheets CFRP Sheet A B C Prestressing (%) ) Strengthening of RC beams Beam A B C None One CFRP sheet Strengthening scheme One prestressed CFRP sheet Prestress to capacity (%) N/A N/A 3 # # 3 # 4 # 5 Notes: 1.Components.Applying epoxy for bonding 3.Anchorage of FRP sheet 4.FRP under prestressing 5.Bonding FRP to RC beam 6.Details of the devices 7.Geometry of the device FRP Material Laboratory Strong Floor Conclusions: 1.The device is capable of prestressing FRP sheets and prestress losses was less than 1% before prestress transfer..flexural capacity increased and midspan deflections decreased significantly after strengthening. Higher performance was achieved due to prestress P 71.1 cm 3. cm 13.4 cm Prestress (Mpa) Load Cell Loading Beam L1=381 mm L1=457 mm L1=533 mm L1=61 mm L1=686 mm 44 x 3.5 cm Test Beam Support Plates Test setup for RC beams Vertical displacement (mm) Deterrmination of the prestress A Tensioning stress(%) B Prestress after relaxation(%) FRP sheet under prestressing L 3 L 3 B Before prestressing C D L L L L Time (hrs) Test results for concrete walls C H # 7

16 Strengthening of masonry (URM) walls with polyurea Piyong Yu (Graduate Research Assistant) Dr. P.F. Silva (Faculty Advisor) Bondo May 7 th & 8 th, 4 1) Investigate the application of polyurea in structural strengthening ) Investigate the performance of strengthened infill masonry walls Background : Polyurea has been successfully used in spray coating system, including corrosion protection, containment, and others. Application of grid reinforced polyurea in unreinforced masonry (URM) walls strengthening is studied in this program. # 3 # 4 # 1 # Notes for the pictures: Preparation of the walls Spraying polyurea to the specified area Test setup for URM walls Failure mode for wall CO B Failure mode for wall CY E Testing Matrix: 1) Concrete walls (Polyurea) Walls CO A CO B CO C CO D CO E ) Clay bricks walls (polyurea) Walls CY A CY B CY C CY D CY E Walls G 1 G G 3 G 4 G 5 Strengthening scheme None Four horizontal GFRP grids Eight horizontal GFRP grids Four vertical GFRP grids Eight vertical GFRP grids Strengthening scheme None Four horizontal GFRP grids Eight horizontal GFRP grids Four vertical GFRP grids Eight vertical GFRP grids Previous Test: Strengthening scheme Four horizontal GFRP strips Sides -- Single Both Single Both Sides Single Both Single Both Four vertical GFRP strips plus seven # GFRP bars (horizontal) Seven horizontal GFRP strips Four horizontal GFRP strips Seven horizontal CFRP strips -- # 5 Conclusions: 1.Strengthening of URM walls with grid reinforced polyurea is an effective scheme.. Compared with strengthening with epoxy bonded FRP sheets, grid reinforced polyurea demonstrated better performance. Diagonal Load (kips) CY A CY B CL 1 CL Walls Test results for clay bricks walls Diagonal Load (kips) CO A CO B CO C CO D CO E G 1 Walls G G 3 G 4 G 5 Test results for concrete walls

17 Blast Resistance of Masonry Infill Wall / RC Frame Connections using FRP Systems May 7 th, 4 To investigate the feasibility of using FRP materials to develop continuity between RC frame elements and masonry infill wall systems for blast resistance. The study will also investigate the energy absorption or dissipation and deflection ductility of the control and hybrid wall strengthening systems. Preston Carney (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) NSF Industry/University Cooperative Research Center Simulated Blast (Static) Test Setup: Connection Details Under Investigation: Wall Test Matrix: Phase I Retrofit Scheme* Unstrengthened Unstrengthened 1.5 GFRP Sheets.5 GFRP Sheets 1 # GFRP Rods # GFRP Rods 1 # GFRP Rods.5 GFRP Sheets Hybrid.5 GFRP Sheets Running Bond 4.5 GFRP Sheets 6.5 GFRP Sheets Completed * Reinforcement placed vertically in or along the head joints 1 Top and bottom course grouted Reinforcement not anchored to concrete GFRP Anchored Laminate Detail Near Surface Mounted GFRP Rod

18 Wall Blast Resistance of Masonry Infill Wall / RC Frame Connections using FRP Systems May 7 th, 4 Test Matrix: Phase II Retrofit Scheme Completed Preston Carney (Graduate Research Assistant) Dr. John J. Myers (Faculty Advisor) NSF Industry/University Cooperative Research Center Field Blast Test Setup: 1.5 GFRP Sheet 1.5 GFRP Sheet * Reinforcement placed vertically in or along the head joints 1 Top and bottom course grouted Reinforcement not anchored to concrete Pressure (psi) Test Results: Deflection (in * 1 3 ) Pentolite Charge Wall #1 Wall # Wall #3 Wall #4 Wall #5 Wall #6 Wall #7 Wall #8 Wall #9 Wall #1 Wall #11 Wall #1 Pressure (psi) Wall #1 Wall # Wall #3 Continuity Detail after Blast Testing Wall #4 Wall #5 Wall #6 Wall #7 Wall #8 Phase I: Peak Pressure at Failure

19 Design, Fabrication and Testing of Low-Profile Composite Bypass Road Panel May 7 th 8 th 4 Demonstrate the feasibility of GFRP systems for low-profile bypass roadways, in particular, sandwich panels comprised of GFRP facings and Fiber Reinforced Foam (FRF) core. Silvia Rocca (Graduate Research Assistant) Dr. A. Nanni (Faculty Advisor) MODOT; Webcore Technologies, Inc. Background: The availability of lightweight FRP sandwich panels, not only for bridge decks, but also for temporary bypass roadways, has been identified as an interesting alternative to traditional construction methods. The suitability of the material for the purpose has been identified after its mechanical characterization. FATIGUE FLEXURAL TEST SETUP SCHEMATIC OF HYBRID FRF CORE Conclusions: There is not significant loss of compressive strength. The maximum residual strength after million cycles was 87 psi. Based upon de experimental results and analysis regarding the possible field application (fully supported panel), a length of 8ft is considered appropriate. FATIGUE COMPRESSIVE TEST SETUP APPLICATIONS FULLY SUPPORTED PANEL SERVICIABILITY PERFORMANCE S B3 B B1 A1 B1 A1 B1 A1 A1 A1 A1 CONDITIONING LOAD S VS. NUMBER OF CYCLES N; COMPRESSIVE TEST B1 A1 B1 B A1 B Midspan Deflection (in) L = 4 ft L = 8 ft L = 1 ft L infinite L 8 L = 8 ft N Soil Elastic Modulus (lb/in 3 )

20 Flexural Strengthening of Corroded Steel Bridge Members with Composite Materials May 7 th & 8 th, 4 To investigate the effectiveness of externally bonded composite materials to regain the original design moment capacity and to design a retrofit procedure for strengthening of corroded steel members. Design approach is based on balancing the force lost due to corrosion to the force gain from externally bonded composite material. From this area of the material required for retrofit is: μ all φ Retrofit Design: f A frp frp A = f = φμ all cor frp F l t b frp : Design bond stress from pull-out tests : Strength reduction factor d Tarun Gupta (Graduate Research Assistant) Dr. P.F. Silva and Dr. A. Nanni (Faculty Advisors) Federal Railway Administration (FRA) Background : Traditional methods of retrofitting the corroded steel bridge members involves high material costs and labour and increase the weight of the structure. To substantiate these disadvantages, the use of composite materials have shown promising results to regain the flexure integrity of such deteriorated steel members. Mid-span Moment [kn-m] M P O M Y O M D O Unit 1-N-3 Unit -C-3 Unit 3-E-3 Unit 4-E Mid-span Deflection [cm] Mid-span Moment [kn-m] Unit 5-N-4 Unit 6-C-4 Unit 7-T-4 Unit 8-T-4 Unit 9-S-4 Unit 1-S-4 Unit 11-S-4 M P O M Y O M D O Mid-span Deflection [cm] Test Unit 1-N-3 -C-3 3-E-3 4-E-3 5-N-4 6-C-4 7-T-4 8-T-4 9-S-4 1-S-4 11-S-4 Test Matrix Strengthening Material - - CFRP CFRP - - CFRP CFRP SRP SRP SRP Bonded Length - - Full Quarter - - Full Half 1 Ply Full Ply Full 3 Ply Full N: No simulated corrosion-control unit C: Corrosion was simulated-control unit E: Adhesive-Enforce CFL T: Adhesive-Tyfo MB S: Adhesive-Sikadur 33 Conclusions: All the retrofitted specimens failed by debonding of the composite material above the original allowable design moment. Adhesive is a crucial factor that influence the bond performance between the composite material and the steel substrate.

21 Strengthening of Un-Reinforced Masonry Walls with FRP Tong Li (Graduate Research Assistant) Dr. Nanni (Faculty Advisor) NSF Industry/University Cooperative Research Center May 7 th 3 Investigate the efficiency of different strengthening schemes on improving the inplane structural performance of FRP strengthened unreinforced masonry (URM) walls with central openings. Finite Element Analysis Background : URM walls is a source of great concern because their failure during seismic events has many times been identified as one of the major causes of property and human losses. Test Setup Load vs. Deformation Response Load (kips) Top Displacement (cm) A 1B A B C D Damage of URM Walls (Turkey, 1999) 1 5 Load (KN) -5-1 UNIT 1A 1B A B C D Test Matrix: Test Method R,C R,C R,FC R,FC R,FC R,FC RETROFIT SCHEME Controlled Unit 8 -# H. GFRP Rods Controlled Unit 8 -# H. GFRP Rods 8 -# V. GFRP Rods B+C R: Racking Test H: Horizontal V: Vertical C: Cyclic FC: Fully Reversed Cyclic 1A,A 1B,B C D Conclusions: FRP Reinforcement FRP composites are efficient in improving the performance of URM walls and NSM GFRP bars were observed to work properly with masonry; Vertical reinforcement in the piers significantly increased the stiffness, maximum lateral load-carrying capacity and energy dissipation capacity of URM walls; Strengthening with a combination of horizontal and vertical reinforcement significantly improved the overall structural behavior of URM walls including lateral load-carrying capacity, stiffness, and maximum displacement capacity Top Displacement (in.)