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HomeMy WebLinkAbout03 38 10 - Post-Tensioned Vehicular Barrier Cable SystemMidtown West 17070 Carmel, Indiana September 15, 2017 03 38 10 - 1 SECTION 03 38 10 - POST-TENSIONED VEHICULAR BARRIER CABLE SYSTEM PART 1 - GENERAL 1.1 SECTION INCLUDES A. All labor, materials, equipment, special tools and services to complete barrier cable system work for the Project as herein specified, and as indicated on the Drawings. 1.2 RELATED SECTIONS A. Section 03 30 00 – Cast-in-Place Concrete B. Section 03 38 00 – Post-Tensioned Concrete 1.3 REFERENCES A. Post-Tensioning Institute (PTI) Specification for Seven-Wire Strand Steel Barrier Cable Applications. B. ASTM A416: Standard Specification for Steel Strand, Uncoated Seven-Wire for Pre- stressed Concrete. C. Other ASTM references as noted in this Section. D. Post-Tensioning Institute (PTI): Specification for Unbonded Single Strand Tendons, Second Edition. E. Post-Tensioning Institute (PTI): Field Procedures Manual for Unbonded Single-Strand Tendons, Third Edition. 1.3 SUBMITTALS A. Submit shop drawings showing complete details of vehicular barrier system, including arrangement and number of tendons, methods of maintaining hole and alignment through column, detailing of anchorage devices, live end anchor locations, sequence of tensioning, and strand repair procedures. B. With shop drawings, and before installation of any vehicle barrier strands, submit detailed calculations. Refer to paragraph 1.4A below. C. Submit tendon sample including wires, tensioning anchorages, and associated hardware. D. Submit independent testing laboratory certification for all grease used showing full compliance with Table 1 in PTI Specification of Unbonded Single Strand Tendons. E. Submit calibration certificates for every jack and gauge used on the Project. F. Submit static and fatigue test reports of representative anchorage assemblies to be used on the Project in accordance with PTI Specification for Unbonded Single Strand Tendons. Midtown West 17070 Carmel, Indiana September 15, 2017 03 38 10 - 2 G. Submit experience records of post-tensioned system installer. Records to include list of project experience of installer’s superintendent. Refer to paragraph 1.5 B below. H. Submit written certification that the plant manufacturing the post-tensioned Vehicular Barrier Cable System complies with the PTI Certification Program. I. Submit copies of certified mill test reports for each coil or pack of strand used for the Project in accordance with PTI Specification for Seven Wire Steel Strand Barrier Cable Application. J. After review, shop drawings and data shall not be changed nor shall construction operations be deviated from unless resubmitted. K. Architect/Engineer’s review of details and construction operations shall not relieve Contract of the responsibility for completing the work successfully in accordance with these Specifications and within Contract time. 1.4 SYSTEM REQUIREMENTS A. System design: 1. The Contractor shall be responsible for the structural design and detailing of vehicular barrier system. The structural design and detailing of connections shall be in accordance with the following provisions and those identified on the drawings. 2. Design vehicular cable barrier system per Chapter 16 of the PTI Post-Tensioning Manual. 3. Design system under the direct supervision of a suitably qualified and experienced structural Professional Engineer, who shall sign and seal the shop drawings of the work for which he was responsible. B. Design system to resist the following live loads: 1. Vehicular Impact per KBC Section 1807.7.3; 8000# Working Load (10,000# Ultimate) at 18 inches above the floor or ramp. 2. Guardrails per KBC Section 1607.7.1; 50#/lf and 200# concentrated load applied in any direction. C. Vehicular barrier profile as shown on the drawings and in accordance with IBC Sections 406 and 1013. D. Deflection requirements: 1. Limit sag in the strand to 0.007 in/ft. 2. Limit maximum horizontal deflection to 18” under impact loading. 1.5 QUALITY ASSURANCE A. Furnish the necessary information, materials, accessories and other items for pre- stressing and attaining the effective prestressing forces. The Post-tensioning (PT) Subcontractor responsible for the work of this Section shall perform with his own forces the field labor for placing and stressing of post-tensioning materials. B. Installation shall be performed by individuals holding a current certificate as a PTI Certified Installer of Unbonded Post-Tensioning. Furthermore, all prestressed reinforcing Midtown West 17070 Carmel, Indiana September 15, 2017 03 38 10 - 3 work shall be under the immediate control of the PT Subcontractor’s superintendent, who shall have supervised at least five (5) prior projects of similar magnitude and design. PT superintendent shall exercise rigid control of all operations as necessary for full compliance with contract document requirements. C. Plant certification: 1. Post-tensioned barrier cable system shall be manufactured in a plant certified to comply with the PTI Program for Certification of Plants Producing Unbonded Single Strand Tendons. 2. Plant to be certified as of the date bids are received by the Owner of this Project, and at the time post-tensioning system is manufactured and delivered for this Project. 1.6 DELIVERY, STORAGE, AND HANDLING A. Protect tendons from moisture and rust from time of initial fabrication until installation. Store tendons above ground at all times. B. Deliver, store and handle post-tensioning materials in accordance with PTI’s Field Procedures Manual. C. Use nylon straps during loading, unloading and handling of materials. PART 2 – PRODUCTS 2.1 MANUFACTURERS A. Pre-qualified Barrier Cable System Manufacturers: 1. AMSYSCO, Inc. 2.2 POST-TENSIONING STEEL A. Vehicular barrier cable tendons shall be 0.5” diameter strands. End anchorage sizes shall be selected by vehicular barrier subcontractor and submitted to Architect/ Engineer for review. B. Strands: 1. Conform to ASTM A416 Standard Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete. Provide stand conforming to (GBS) “Galvanized Barrier Strand” or (GPC) “Galvanized Prestressed Concrete Strand.” 2. Strand to have minimum ultimate tensile strength of 270,000 psi. C. Temporary stress shall not exceed eighty (80) percent of the minimum ultimate tensile strength of the strand. D. Maximum allowable anchor slip is 1/8”. E. Broken strands, and strands showing severe fabrication defects, shall be removed and replaced. Midtown West 17070 Carmel, Indiana September 15, 2017 03 38 10 - 4 2.3 ANCHORAGES AND COUPLERS A. Anchorages and couplers shall comply with PTI Specification for Unbonded Single Strand Tendons and ACI 318. Anchors shall be designed for transfer at 2,500 psi concrete strength. B. Size bearing plates of anchorages to satisfy requirements of ACI 318 and PTI Specification for Unbonded Single Strand Tendons unless certified test reports are submitted providing acceptable deviation. C. Anchorages and couplers shall be capable of developing at least 95% of the actual breaking strength of the prestressing steel without excessive deformation. Total elongation of the tendon under ultimate load shall not be less than 2% measured in a minimum gauge length of three (3) feet. D. Insert devices may be preset prior to column placement. All inserts shall meet the ultimate pull-out and shear load requirements of the design and as a minimum, shall meet the impact load requirements. Inserts shall be rated on a minimum 4:1 factor of safety for ultimate pull-out and/or shear. E. If encapsulated anchorages are provided, tendon anchorage blocks shall be epoxy- coated or encapsulated in plastic. F. Caps over the wedge cavity at stressing end anchorages to be supplied pre-greased. G. The anchorage casting and wedges shall be supplied by the same manufacturer. 2.4 CORROSION PREVENTATIVE COATING A. Galvanized Coating: 1. Provide zinc coating complying with ASTM Specification A 475 Class A, Table 4 coating weight. 2. Apply coating by either hot-dip, hot-dip and post-drawing, or electroplating process that ensures complete zinc coating around each individual wire of the strand. 2.5 FASTENERS A. Use stainless steel nails to secure post-tensioning to forms or surfaces which will be exposed in the finished structure. PART 3 – EXECUTION 3.1 INSTALLATION OF BARRIER CABLES THROUGH COLUMNS A. Provide a hole at intermediate columns that is a minimum of 1/8” diameter larger than the barrier cable diameter, including coating material. B. Prior to column concrete placement provide one of the following anchorages at end columns: 1. Recessed stressing anchors. 2. External barrel anchors. Midtown West 17070 Carmel, Indiana September 15, 2017 03 38 10 - 5 3. Threaded anchoring devices and concrete inserts capable of developing the single strand design load. C. Firmly support conduits and anchorages to prevent displacement during subsequent operations. Place with a vertical tolerance of plus or minus 1/8”. 3.2 TENSIONING A. Stress all barrier cables to a minimum force of 3 kips to prevent sagging. Seating loss and length of cable shall be considered to ensure the specified force is achieved after back-stressing. B. All fixed and stressing anchorages shall be back-stressed. Back-stressing is performed after cable is stressed. Place jack on opposite side of bearing member and stress cable to a force equal to 80% of the strand minimum ultimate tensile strength. Use slotted bearing plate to prevent damage to backside of the member by jack nose. C. Prestressing operations may not be performed at night. D. Jack chucks shall be checked for uneven wear before each use and shall be replaced if such wear is evident. E. Stressing pockets shall be a minimum of 2” deep. Pockets shall be filled with non-shrink grout as soon as practical after tendon stressing and cutting. 1. Within one work day after tendon tails are cut, coat exposed strand and wedge areas with tendon coating material and apply watertight cap over the coated area. 2. Prior to installing pocket grout, inside concrete surfaces of the pocket shall be coated or sprayed with a resin bonding agent. 3. Under no circumstances shall grout or mortar used for pocket filling contain chlorides or other chemicals known to be deleterious to prestressing steel. 4. Grout to confirm to Section 03 30 00. 5. Finish grout pockets flush with surrounding concrete. 6. Cure grout in accordance with Section 03 30 00. 7. Rub out all stressing pockets. 3.3 PROTECTION AND STORAGE OF MATERIALS A. No material shall be stored on prestressed slabs before final stressing of the slabs and supporting beams is complete. At no time shall the weight of stored material and construction live loads placed on the slabs exceed the total superimposed design load of the slab or beams. END OF SECTION 03 38 00