DYWIDAG Soil Nails. Dallas Cowboy Stadium, Dallas, TX

Transcription

1 DYWIDAG Soil Nails Dallas Cowboy Stadium, Dallas, TX

2 References Retaining Wall at Dallas/Fort Worth International Airport, TX Secured with DYWIDAG Soil Nails Part of the extensive and ambitious expansion of Dallas/Fort Worth Airport included numerous roadways in and around the congested airport infrastructure. Some roads required significant cuts and retaining walls next to many existing bridges, buildings and roadways. In order to support the adjacent structures and roads, more than 16,400 ft DYWIDAG Soil Nails were installed. The soil nail method of construction allowed for the least disruption of the adjacent structures and movement of people and vehicles. Soil Nail retaining walls require minimum excavation and are installed faster than alternate types of retaining walls. i Owner Dallas/Fort Worth International Airport, TX, USA +++ Contractor Craig Olden, Inc., Little Elm, TX, USA +++ Installed by Craig Olden, Inc., Little Elm, TX, USA DSI Scope Supply of approximately 650 DYWIDAG Soil Nails size #8, total length about 16,400 ft San Manuel Indian Casino, Highland, CA i Owner San Manuel Band of Mission Indians, Highland, CA, USA +++ General Contractor Bomel Construction Anaheim, CA, USA +++ Constructor Pennhall Company, Las Vegas, NV, USA +++ Subcontractor Condon-Johnson & Assoc., San Diego, CA, USA +++ Engineers PB&A (Pirooz Barar & Assoc.), San Anselmo, CA, USA DSI Unit DSI USA, BU Geotechnics, Long Beach, CA, USA DSI Scope Supply of 481 double corrosion protected DYWIDAG soil nails #8 grade 75: S 520/690 N/mm², 193 double corrosion protected DYWIDAG V-Nails #8 grade 75: S 520/690 N/mm² and #8 grade 75: S 520/690 N/mm² test nails

3 Contents DYWIDAG Soil Nails... 4 Construction of a Soil Nail Wall... 5 Soil Nails - Options for Materials... 6 Corrosion Protection... 7 Bar Properties... 8 Hardware Properties... 9 DYWI Drill Hollow Bar System Anchorage System and Centralizers Soil Nail Testing References

4 DYWIDAG Soil Nails History The technique of soil nailing began to evolve in the early 1970 s. Major research programs in Germany in the mid to late 70 s and in France in the late 80 s advanced this method of construction. It has been successfully utilized worldwide for excavation support and slope stabilization and its use continues to grow rapidly. General Notes Applying the principles of systematic rock anchoring to soil seems to be obvious, but the requirements for soil nailing are higher. The many years of experience gained with pressuregrouted anchors have resulted in a certain level of standards, however, the stability of the supported soil mass must be verified for all stages. Soil nails are used for stabilizing slopes and excavations. They find an efficient application in granular soils of medium to high density with sufficient internal friction, so that a good load transfer along the soil nail is possible, and only slight creep movements occur in the supported soil mass. The soil nails are installed as the excavation progresses from top to bottom. The surface of the cut is usually stabilized by shotcrete and rebar mats. Since the soil nails are loaded only by ground movement, a certain outward deflection of the top of the stabilized wall must be expected. The theoretical pivot of the wall is at the bottom of the excavation. Calculations assume the maximum tensile force in the earth mass to occur at a distance from the wall equal to 1/3 to 1/2 of the wall height. There, parallel to the wall, the interface between the unstable soil and the retaining stable ground must be assumed. This location is also the area of the highest bending for the soil nails. The anchoring length of the soil nails must extend into stable ground. DSI has been a pioneer in the use of soil nails to reinforce existing ground. Today DSI is widely recognized as the principal worldwide source for soil nails meeting the most demanding performance requirements. Advantages Design Considerations of soil nail walls Top-down construction Light construction equipment Lower construction costs versus tieback walls with soldier beams and lagging of DYWIDAG soil nails Can be used for temporary and permanent applications Simple components and component assembly Easy to install and test Durable threads. Allow splicing at any point along the length Requirements for the site Design Life (permanent or temporary wall) Corrosion Protection Pullout resistance between nail and the ground Individul nail capacity (strength and length) Length of nail to reach beyond the failure surface Nail spacing (typically 4-6 ft) cip and architectural treatment existing grade drainage varies driving forces Nail inclination (typically deg.) Wall inclination Stability analysis for each stage of construction Allowable horizontal and vertical displacement limits Dewatering, if below the ground water table Drainage system surcharge assumed failure surface resisting forces Stable, self-supporting soils at the excavation face Benches strong enough to support drilling equipment for the Soil Nail System High tensile and shear strength High ductility High bond strength Ability to accommodate structural and non structural face attachments wall height primary shotcrete wall bottom of wall Typical section Soil Nail Retaining Wall soil nail adheres to soil on both sides of failure surface 4

5 Construction of a Soil Nail Wall Excavate soil Drill hole Install and grout nail Test selected nails Place reinforcement Place shotcrete Finish shotcrete Install soil nail plate, washers and nut Excavate for the next level of nails 5

6 Soil Nails - Options for Materials WALL THICKNESS SHOTCRETE FACING CIP CONCRETE ARCHITECTURAL TREATMENT (TYP.) BACK FACE OF SHOTCRETE HEX NUT OR ANCHOR NUT (TYP.) IES) 3 H (VAR M A15 LENGT R AST TOTAL ED PE IZ N A ALV G IP D OTCOUPLERS AS REQUIRED E OR H C L SOIL NAIL ASSEMBLY (TYP.) ANGLE VARIES (TYP.) BAR DYWI Drill Hollow Bar n n n Bare Epoxy coated Galvanized BEVEL WASHERS SET (TYP.) CONCRETE ANCHOR USED FOR PERMANENT SOIL NAILS (TYP.) HOLLOW-CORE SELF-DRILLING ROD E D HOL DRILLE BEARING PLATE ASSEMBLY (TYP.) FIELD GROUT DRILL BIT BACK FACE OF SHOTCRETE TOTAL EPOXY ARIES) GTH (V LEN ASTM D PER COATE 3" CLR. THREADBAR H LENGT TED A UNCO 775 STM A RA A934 O CONCRETE COVER (TYP.) n n n Bare Epoxy coated Galvanized E D HOL DRILLE SOLID REINFORCING STEEL BAR PER ASTM A615 OR A722 HOLE CENTRALIZER NAIL GROUT BACK FACE OF SHOTCRETE ARIES) GTH (V N LE TOTAL 3" CLR. 4 M A93 R AST PE OATED C EPOXY THREADBAR H LENGT TED A UNCO n Epoxy coated plus partial DCP 775 TM A OR AS ED RUGAT UTED 0" COR REGRO L = 3'HOP P S G IN HEATH S D HOL DRILLE SOLID REINFORCING STEEL BAR PER ASTM A615 OR A722 E HOLE CENTRALIZER CORRUGATED HDPE OR PVC SHEATHING 40 MIL MIN. THICKNESS NAIL GROUT THREADBAR ARIES) GTH (V OUTED PREGR SHOP BACK FACE OF ATHING LENGTH E H S D MENT UGATE SHOTCRETE CORR EMBED ENTIRE TOTAL LEN NAIL GROUT 3" CLR. D HOL DRILLE E HOLE CENTRALIZER 6 SOLID REINFORCING STEEL BAR PER ASTM A615 OR A722 CORRUGATED HDPE OR PVC SHEATHING 40 MIL MIN. THICKNESS H LENGT TED A UNCO n Full length DCP

7 Corrosion Protection DYWIDAG soil nails can be protected against corrosion in a variety of ways suitable for both temporary (<24 months) and permanent (>24 months) applications. Bare bar in cement grout Cement grout alone can be used for corrosion protection of temporary soil nails and permanent nails in non-aggressive ground provided the thickness of the grout cover exceeds 1-1/2 (38 mm). The DYWI Drill bar system is ideally suited for temporary soil nails particularly in non-cohesive soils. Sacrificial steel Steel elements of the soil nail system can be oversized to allow for loss of cross sectional area due to corrosion. The rate of corrosion shall be based on historical data for ground conditions with the same or lower level of aggressiveness. Additional factors of safety are recommended. Hot Dip Galvanizing Permanent soil nails in non-aggressive ground can be protected against corrosion by hot dip galvanizing in accordance with ASTM A-153. Hot dip galvanizing of GR150 bars requires specialized procedures to avoid hydrogen embrittlement. Epoxy coating DYWIDAG soil nails in non aggressive ground and temporary nails in aggressive ground can be protected against corrosion by epoxy coating in accordance with ASTM A-934 or ASTM A-775. Although ASTM A-934 has shown better performance than A-775 coating, it is not available in all areas of North America. With the DYWIDAG system it is possible to epoxy coat the entire length of the bar. Oversized hardware is available to thread over a coating up to 10 mils thick. ASTM A-934 is usually purple or gray in color while ASTM A-775 is green in color. Epoxy coated DYWIDAG threadbar Epoxy coated bar with partial or full DCP Partial Double Corrosion Protection (DCP) protection over epoxy-coated bar provides additional protection in areas considered most corrosive. A bar that is epoxy coated over its entire length with a pregrouted plastic sheathing is often referred to as a triple corrosion protected soil nail. This type of corrosion protection is used in extremely aggressive environments. Partial DCP over epoxy coated threadbar Double Corrosion Protection DCP The most reliable corrosion protection for soil nails in permanent applications or for nails used in critical structures is to pregrout the nail in corrugated PVC or HDPE sheathing. The sheathing provides a watertight barrier. Tests have proven that the deformations of the THREADBAR limit crack width to 0.1 mm (4mils). DCP threadbar cross section DCP threadbar exposed section Epoxy Coated DYWI Drill Bar 7

8 Bar Properties THREADBAR DYWIDAG THREADBAR Reinforcing Steel ASTM A615 (Grade 75) THREADBAR Designation Maximum THREADBAR Diameter Yield Stress (fy) Cross Section Area (As) Yield Load (fy x As) Nominal Weight [in] [mm] [in] [mm] [ksi] [MPa] [in²] [mm²] [kips] [kn] [lbs/ft] [kg/m] # # # # # # , # , Note: Maximum test load = 90% of the yield load Mill length = 60'-0" for #6 through #24 bars and 48'-0" for #28 bars DYWIDAG THREADBAR Prestressing Steel ASTM A722 (Grade 150) THREADBAR Designation Maximum THREADBAR Diameter Ultimate Stress (fu) Cross Section Area (As) Ultimate Load (fu x As) Nominal Weight [mm] [in] [mm] [ksi] [MPa] [in²] [mm²] [kips] [kn] [lbs/ft] [kg/m] 1" , /4" , /8" , , , *1-3/4" , , , * Meets the strength requirements of the A 722. Note: Maximum test load = 80% of the ultimate load Mill length = 60'-0" for 1", 1¼" and 1 " Threadbars and 45'-0" for 1¾", 2½" and 3" bars 8

9 Hardware Properties A Anchor Nut B B/2 B/2 H Hex Nut Bearing Washer ØC Wedge Washer Coupler Bevel Washers ØW ØV DYWIDAG nuts and couplers develop the ultimate load of the bar. DYWIDAG THREADBAR Reinforcing Steel Hardware Properties THREADBAR Designation Hex Nut Length H Coupler Length B Coupler Outer Diameter Ø C Maximum Angle Compensation * Bevel Washer Diameter Ø V [in] [in] [mm] [in] [mm] [in] [mm] [degrees] [in] [mm] # # # # # # # * using two washers in a set. Solutions for large bars and larger angles are available please consult your local DSI Sales Engineer DYWIDAG THREADBAR Prestressing Steel Hardware Properties THREADBAR Designation Nut Length A / H Coupler Length B Coupler Outer Diameter Ø C Maximum Angle Compensation * Wedge Washer Diameter Ø W [in] [mm] [in] [mm] [in] [mm] [degrees] [in] [mm] 1" 2.36 / / /4" 3.15 / / / / /8" 3.53 / / /4" 3.50 / / * using two washers in a set. Solutions for large bars and larger angles are available please consult your local DSI Sales Engineer 9

10 DYWI Drill Hollow Bar System General Notes The DYWI Drill Hollow Bar System is a fully threa ded steel bar which can be drilled and grouted into loose or collapsing soils without a casing. The bar features a hollow center for simultaneous drilling and grouting and a rope thread for connection to standard drill tooling. Manufactured by cold rolling heavy wall steel tubing, DYWI Drill Hollow Bar forms a standard rope thread profile (R25 - R51, T76 has a trapezoidal thread). The rolling process refines the grain structure of the steel, increasing the yield strength and producing a durable drill rod suitable for a range of applications. DYWI Drill Hollow Bars can be installed into a variety of different soils and ground conditions ranging from sand and gravel to inconsistent fill, boulders, rubble and weathered rock, as well as through foo tings and base slabs. Installation Advantages Ability to work with small drill rigs without casing in narrow spaces Similar installation methods for all ground conditions Simultaneous Drill and Grout Installation Combines both operations into a single construction cycle, enabling high rates of production. No Casing Required Can be installed into loose or collapsing soils without the need for a temporary casing to support the borehole. Rotary Percussive Drilling Enables quick rates of installation, good directional stability and assists in the consolidation of the grout within the borehole. Material Characteristics Fully Threaded Rod Sections Continuous thread ensures that rods can be cut and coupled at any point. Thread Profile Standard ISO rope thread (R25-R51) or trapezoidal thread (T76) produces an excellent bond between the bar and grout, and enables connection to conventional drill tooling. The hollow core serves for flushing with air or water during drilling, but also for grouting the hole. Choice of drill bits for different ground conditions Enhanced corrosion protection is available upon request DYWI Drill Hollow Bar Properties Bar Designation Average Yield Average Ultimate Average Cross Yield Load Ultimate Load Nominal Outer Stress Tensile Stress Section Area Nominal Weight Diameter (fy) (fu) (As) (fy x As) (fu x As) [in] [mm] [ksi] [MPa] [ksi] [MPa] [in²] [mm²] [kips] [kn] [kips] [kn] [lbs/ft] [kg/m] R25N R32N R32S R38N R51L T40N R51N T76N , , , T76S , , , Note: Maximum allowable, temporary test load is 100% of the yield load. Average cross section area is based on average internal diameter of the bar. The ultimate and yield load capacity are measured values. The ultimate tensile and yield stress are calculated average values. Mill length is 9-10 (3m). Longer lengths can be special order. 10

11 hexnut hollow bar coupler cement grout domed or flat bearing plate drill bit (various drill bits are available for different ground conditions) Bar / Grout bond DYWI Drill Hollow Bar Hardware Properties Bar Designation Hex Nut Length H Coupler Length B Coupler Outer Diameter Ø C Maximum Angle Compensation * Bevel Washer Diameter Ø V [in] [mm] [in] [mm] [in] [mm] [degrees] [in] [mm] R25N R32N R32S R38N R51L T40N R51N T76N T76S * using two washers in a set. Solutions for large bars and larger angles are available please consult your local DSI Sales Engineer 11

12 Anchorage System and Centralizers Bearing Plate Assembly Bearing plates are available in any size with or without welded concrete anchors (studs). ASTM A36 and ASTM A572 grade 50 steel material are used for the bearing plates, stud materials conform generally to ASTM A108. Threadbar Anchorage with studs One or two beveled washers are used typically to adjust to the soil nail angle. DYWI Drill Hollow Bar Anchorage without studs Centralizers Centralizers made from PVC are available for all hole diameters and nail configurations. They are used mostly with threadbar soil nail. Wall Forming with DYWIDAG Soil Nails When your project requires a castin-place wall in front of the complete soil nailed wall, DSI offers a variety of methods to use the existing soil nails as a means of vertical form support. Reusable she-bolts are available for some of the more common THREADBAR sizes (see the detail to the right) For any DYWIDAG Soil Nail, a coupler with an extension bar provides a simple and effective means of transferring form loads to the nails. A sleeve over the bar allows for multiple reuse of the extension bar and anchorage. DYWI Drill Centralizer and Drill Bit 12

13 bonded length Soil Nail Testing Soil nail testing is performed to establish the bond stress within the stable zone of a slope. Typically no more than 5% of the nails are selected for testing. Nails are incrementally loaded during testing. Tests performed, can include: Ultimate tests (sacrificial) where nails are tested until failure occurs. Proof tests can be performed on sacrificial or production nails. Creep tests are generally conducted during proof or sacrificial testing. Acceptance criteria should be based on allowable movements of the wall over its life span. Since hollow bar nails are fully grouted it is necessary to establish the influence of the wedge zone bond on the total load. This will determine a more accurate assessment of the test load in relation to bond length. Test load is measured with a pressure gauge incorporated in the hydraulic jacking system. Nail movement is recorded by a dial gauge mounted on an independent stand. DSI Testing Equipment DSI Jack/chair assembly calibrated with the pressure gauge are available for all THREADBAR and DYWI Drill Hollow Bar sizes. test frame test soil nail primary shotcrete layer dial gauge supported on independent stand jack fill hole with grout, after testing for production nails test soil nail length block out in shotcrete excavation face initial grout drilled hole diameter 13

14 References Stanley Hall Replacement, U.C. Berkeley, CA i Owner University of California at Berkeley, CA, USA +++ Engineer Pirooz Barrar & Associates (PB&A, Inc.), San Anselmo, CA, USA +++ General Contractor McCarthy Construction, Los Angeles, CA, USA +++ Sub Contractor and Soil Nail Installer Drill Tech Drilling and Shoring, Antioch, CA, USA DSI Scope Supply of 1,545 assemblies (200 t) of DYWIDAG 1 1 / 4 THREADBAR grade 150 Soil Nails with DCP Reno ReTRAC (Reno Transportation Rail Access Corridor), Reno, NV i Owner City of Reno, Nevada, NV, USA +++ General Contractor Granite Construction, CA, USA +++ Design Team Leader Parsons, CA, USA +++ Project Management Jacobs Engineering Group, CA, USA +++ SubContractor (Shoring Contractor) Schnabel Foundation Co., CA, USA DSI Scope Supply of more than 8,000 R38 DYWI Drill Hollow Bars supporting 180,000 SF of soil nail wall 14

15 References Brantford General Hospital, Brantford, Ontario, Canada Shotcrete wall with DYWI Drill Hollow Bar i Owner Brantford General Hospital, Brantford, Ontario, Canada +++ General Contractor Bondfield Construction, Concord, Ontario, Canada +++ Consulting Engineers Carruthers & Wallace Limited, Toronto, Ontario, Canada +++ Contractor for foundations HC Matcon Inc., Ayr, Ontario, Canada +++ Engineer for foundations Isherwood Associates Ltd., Mississauga, Ontario, Canada DSI Scope Supply of 40,000 ft DYWI Drill Hollow Bar Soil Nails for the shotcrete wall Additional Geotechnical Products from DSI DYWIDAG Bar Anchor Systems... DYWIDAG Driven Ductile Iron Pile... DYWIDAG Micropiles... DYWI Drill Hollow Bar Systems... DYWIDAG Strand Anchor Systems... DYNA Force TM Elasto Magnetic Sensor... 15

16 DYWIDAG-Systems International USA Inc. 320 Marmon Drive Bolingbrook, IL Phone (630) Fax (630) E. Atlantic Blvd #200 Pompano Beach, FL Phone (954) Fax (954) South Royal Atlanta Drive Tucker, GA Phone (770) Fax (770) Hwy 287 N. Suite 106 Mansfield, TX Phone (817) Fax (817) South Street Long Beach, CA Phone (562) Fax (562) Central Ave South Suite 100 Kent, WA Phone (253) Fax (253) Newark Road Toughkenamon, PA Phone (610) Fax (610) Please note: This brochure serves basic information purposes only. Technical data and information provided herein shall be considered non-binding and may be subject to change without notice. We do not assume any liability for losses or damages attributed to the use of this technical data and any improper use of our products. Should you require further information on particular products, please do not hesitate to contact us. DYWIDAG-Systems International Canada Ltd. Eastern Division 37 Cardico Drive Gormley, ON L0H 1G0 Phone (905) Fax (905) Quebec Office C.P. 412 St. Bruno, Quebec, QC, J3V 5G8 Phone (450) Fax (450) Western Division th Avenue Suite 103 Surrey, BC V4N 4C4 Phone (604) Fax (604) Calgary Office st Street NE., #204 Calgary, Alberta T2E 6Z2 Phone (403) Fax (403) ARGENTINA AUSTRALIA AUSTRIA BELGIUM BOSNIA AND HERZEGOVINA BRAZIL CANADA CHILE CHINA COLOMBIA COSTA RICA CROATIA CZECH REPUBLIC DENMARK EGYPT ESTONIA FINLAND FRANCE GERMANY GREECE GUATEMALA HONDURAS HONG KONG INDONESIA ITALY JAPAN KOREA LEBANON LUXEMBOURG MALAYSIA MEXICO NETHERLANDS NORWAY OMAN PANAMA PARAGUAY PERU POLAND PORTUGAL QATAR RUSSIA SAUDI ARABIA SINGAPORE SOUTH AFRICA SPAIN SWEDEN SWITZERLAND TAIWAN THAILAND TURKEY UNITED ARAB EMIRATES UNITED KINGDOM URUGUAY USA VENEZUELA US/07.13-web ca