517.01 Post -Tensioning
482 SECTION 517 POST -TENSIONING
517.01 Description
A.General Post -tensioning work consists of stressing concrete by furnishing, placing, and tensioning of post -tensioning steel in accordance wi th details shown in the contract documents and as specified in these specifications. This work consists of providing and installing any appurtenant items necessary for the particular stressing system to be used, including but not limited to ducts, anchor age assemblies and grout used for pressure grouting ducts.
B.Definitions Anchorage assembly. An assembly of various hardware components that secures the end of a tendon after stressing, transferring the tendon force into the concrete. Anticipated set. The wedge set in the design calculation of post -tensioning forces at the time of load transfer. Bar. Coarsely threaded, high strength steel bars, from ⅝ in to 1¾ in [15 mm to 46 mm] in diameter. Bearing plate. Transfers the tendon force directly into a struct ure or the ground. Bleed. Excess flow of water in or out of new grout. Coupler. Transfers the prestressing force between partial length post -tensioning tendons. Duct. Conduit that accommodates post -tensioning steel and provides a space for the grout that protects the steel. Family of systems. Groups of post -tensioning tendon assemblies that use common anchorage devices and design. Fluidity. Measure of time in seconds for a quantity of grout to pass through a flow cone. Grout. Mixture of cementitious materi als and water (with or without mineral additives or admixtures), proportioned to a consistency that can be pumped without segregation into the duct around the post -tensioning steel. Grout cap. Contains the grout and forms a protective cover sealing the pos t-tensioning steel at the anchorage. Inlet. Tubing or duct used to inject the grout into the duct. Outlet. Tubing or duct that allows air, water, grout, and bleed water to escape from the duct. Permanent stress and permanent force. Stress and force remaini ng in the post -tensioning steel after losses induced by the post -tensioning system. POST -TENSIONING 517.01 483 Post -Tensioning. Method of stressing in which tendon tensioning occurs after the concrete reaches the strength required by the Contract. Prestressing steel. Steel element of a post -tensioning tendon, elongated and anchored to provide a permanent prestressing force. Post -tensioning scheme or layout. Pattern, size, and locations of post -tensioning tendons specified by the Designer. Post -tensioning system. An assembly of tendo ns of a size and type required by the Contract that meets the system pressure testing specifications. Internal and external systems are independent of one another. Pressure rating. Maximum estimated pressure that water in a duct or duct component can cont inuously exert without failure (working pressure). Set (also anchor set or wedge set). Total movement of a point on the strand just behind the anchoring wedges during load transfers from the jack to the anchorages. Set movement is the sum of the wedge sli ppage with respect to the anchorage head and the elastic deformation of the anchor components. For bars, set is the total movement of a point on the bar just behind the anchor nut at transfer and is the sum of bar slippage and the elastic deformation of t he anchorage components. Strand. High -strength steel wires wound together. Strands have six outer wires helically wound around a single straight wire of a similar diameter. Tendon. At least one post -tensioning steel element and anchorage assembly that imp art stressing forces to a structural member or the ground. Tendon size. Number of individual strands of a certain diameter or the bar diameter. Tendon type. Location of the tendon relative to the internal or external concrete shape. Thixotropic. Property o f a material that enables it to stiffen in a short time while at rest, but to acquire a lower viscosity when mechanically agitated. Wedge plate. Hardware that holds the wedges of a multi -strand tendon and transfers the tendon force to the anchorage assembl y. Wedge. Conically -shaped device that anchors the strand in the wedge plate.
517.02 Post -Tensioning
484 517.02 MATERIALS Provide Materials in accordance with the following subsections: Material: Subsection: Post -Tensioning Steel Wire 723.05 Bars for Post -Tensioning 723.04 Water 701.04 Post -Tensioning Grout 701.18 Epoxy Resin and Adhesives 701.13 Magnesium Ammonium Phosphate Concrete 701.21 Elastomeric Coating System 737.03
A.Certification of Post -Tensioning Systems Provide post -tensioning systems approved by the Department’s Materials Division through certified test reports from an independent laboratory and submitted by the manufacturer. Ensure the manufacturer tests plastic components at a certified independent laboratory accredited by th e Geosynthetic Accreditation Institute (GAI) or the American Association for Laboratory Accreditation (AALA). The Department will allow an independent laboratory outside the US to certify test reports if the Department’s Materials Division approves of the lab. If modifying or replacing post -tensioning components, retest the system. Provide the Engineer with certification confirming that the plastic from the duct sample complies with the Contract required cell class, stress -crack rating, and the antioxidan t amount in accordance with Subsection 517.02.G, “Duct and Pipe.” Ensure the system components are stamped with the supplier’s name, trademark model number, and catalog designation size. Provide post -tensioning syste ms developed and tested for bar systems, internal corrugated duct, and external smooth duct applications with standard tendons containing 4, 7, 12, 15, 19, and 27 strands. Provide standard tendon sizes consisting of 0.6 in [15 mm] diameter strands.
B.Post-Tensioning System Provide a post -tensioning system to the Engineer for approval. The Department will not allow substitution of components within an approved system. Store materials in a weatherproof building or container. Provide tendons enclosed in an chorages and ducts. The Department will not allow systems that transfer prestressing force by bonding the strand directly to concrete. The Engineer will allow embedded anchors for bars. The Engineer will not allow systems that use formed, ungrouted void s.
C.Post -Tensioning Anchorages Test the anchorages while unbonded to ensure they develop at least 95 percent of the ultimate tensile strength of the post -tensioning steel without exceeding the anticipated set. POST -TENSIONING 517.02 485 Design anchorages so the average concrete be aring stress is in accordance with AASHTO LRFD Bridge Design Specifications . Test and provide written certification that confirms anchorages at least meet testing specifications in AASHTO LRFD Bridge Construction Specifications . Galvanize the anchorage bo dy in accordance with AASHTO M 111. The Engineer will not require galvanizing for other anchorage components. Provide ferrous metal to construct the bearing surface and wedge plate. Bolt a vented, permanent fiber, reinforced plastic grout -cap to the anc horages. Provide wedge plates with centering lugs or shoulders to align them with the bearing plate. Cast anchorages with grout outlets for inspection from the anchorage top or front. Construct grout outlets to facilitate drilling using a straight bit. P rovide an endoscope to allow the Engineer to inspect behind the anchor plate. Alternatively, construct anchorages to facilitate inspection from the top and front, or fabricate two anchorages to provide two inspection entry locations.
D.Bar Couplers Provi de couplers in accordance with AASHTO LRFD Bridge Design Specifications and Bridge Construction Specifications . Test and provide written certification that shows that the couplers are in accordance with AASHTO LRFD Bridge Construction Specifications . The Engineer must approve the use and location of bar couplers for permanent applications.
E.Inlets, Outlets, Valves, and Plugs Provide permanent grout inlets, outlets, and threaded plugs of ASTM A 240 Type 316 stainless steel, nylon, or polyolefin. Ensur e nylon products have a cell class of S -PA0141. Ensure products made from polyolefin contain antioxidants with an Oxidation Induction Time (OIT) of at least 20 min, in accordance with ASTM D 3895. Test the remolded finished polyolefin material for stress crack resistance in accordance with ASTM F 2136. Use an applied stress of 348 psi [2.4 MPa] with a failure time of at least 3 hr. Provide inlets and outlets equipped with pressure rated mechanical shut -off valves or plugs. Ensure inlets, outlets, valve s, and plugs are rated for a pressure of at least 150 psi [1.03 MPa]. Provide inlets and outlets with an inside diameter of at least ¾ in [20 mm] for strand and ⅜ in [10 mm] for single bar tendons and four -strand duct. Provide dual mechanical shutoff valv es when vertically grouting.
F.Permanent Grout Caps Provide permanent grout caps made from fiber -reinforced polymer or ASTM A 240 Type 316L stainless steel. Ensure the resins in the fiber -reinforced polymer are nylon, acrylonitrite butadiene styrene (ABS ), or polyester. Seal the cap with O-ring seals or precision fitted flat gaskets placed against the bearing plate. Place a grout vent on the top of the cap. Provide grout caps with a pressure rating of at least 150 psi [1.03 MPa]. Provide ASTM A 240 Ty pe 316L stainless steel bolts to attach the cap to the anchorage. Provide certified test reports of the steel chemical analysis if using stainless steel grout caps.
517.02 Post -Tensioning
486 G. Duct and Pipe
1.General Provide plastic duct, steel pipe, or both. Provide airtight and watertight connectors, connections, and post -tensioning hardware components that pass the pressure test. Provide smooth, plastic duct in post -tensioning systems for external tendons. Provide corrugated plastic duct in post -tensioning systems for inte rnal tendons .
2.Duct or Pipe Minimum Diameter Provide duct with an internal diameter at least ½ in [13 mm] larger than the outside diameter of the post -tensioning bar. For post -tensioning bars with couplers, provide duct ½ in [13 mm] longer than the out side diameter of the coupler. Provide ducts for multi -strand tendons with a cross -sectional area at least two and one -half times larger than the cross -sectional area of the post -tensioning steel.
3.Connection Tolerance Between Pipe and Duct Connect steel pipe and plastic ducts directly if the outside diameters vary by less than 0.08 in [2 mm]. Use a reducer to fit steel pipes and plastic ducts with diameters outside the tolerances required by the Contract.
4.Steel Pipes Use galvanized Schedule 40 steel pipes where shown on the Plans and in deviation blocks. Equip steel pipes in the tendon anchorage zones with shear transfer devices as shown on the Plans.
5.Corrugated Plastic Duct The Department will not allow the use of ducts manufactured from recycl ed material. Manufacture ducts using seamless fabrication methods. Provide corrugated duct manufactured from uncolored, unfilled polypropylene, in accordance with ASTM D 4101. Provide polypropylene with a cell classification range from PP0340B44544 to PP0340B65884. Provide white duct with antioxidants with an OIT of at least 20 min, in accordance with ASTM D 3895. Provide duct with a non -yellowing light stabilizer. Use Table 517:1 to determine the minimum duct thickness. Table 517:1 Duct Dimensions Duct Shape Duct Diameter, in [mm] Duct Thickness, in [mm] Flat any size 0.08 [2.0] Round 0.9 [23] 0.08 [2.0] Round 2.375 [59] 0.08 [2.0] Round 3.0 [76] 0.10 [2.5] Round 3.35 [85] 0.10 [2.5] Round 4.0 [100] 0.12 [3.0] POST -TENSIONING 517.02 487 Table 517:1 Duct Dimensions Duct Shape Duct Diameter, in [mm] Duct Thickness, in [mm] Round 4.5 [115] 0.14 [3.5] Round 5.125 [130] 0.16 [4.0] Round 5.71 [145] 0.16 [4.0]
6.Testing Requirements for Corrugated Plastic Duct Provide duct system components and accessories in accordance with Chapter 4, Article 4.1 through Article 4.1.8 of International Federation of St ructural Concrete (FIB) Technical Report, Bulletin 7, “Corrugated Plastic Ducts for Internal Bonded Post -Tensioning.” Modify the requirements in FIB Technical Report, Bulletin 7, as follows: Conduct the lateral load resistance test (FIB 4.1.4) without using a duct stiffener plate. Use a load of 150 lbf [667 N] for all sizes; Ensure the wear resistance of the duct (FIB 4.1.7) is at least 0.06 in [1.5 mm] for ducts no greater than 3.35 in [85 mm] in diameter and at least 0.08 in [2 mm] for ducts greater than 3.35 in [85 mm] in diameter; Ensure the bond behavior of the duct (FIB 4.1.8) achieves 40 percent Guaranteed Ultimate Tensile Strength GUTS in a maximum length of 16 duct diameters.
7.Minimum Bending Radius for Corrugated Plastic Duct Ensure the man ufacturer establishes the minimum -bending radius for the duct through testing. The test consists of modifying a duct wear test in accordance with Chapter 4, Article 4.1.7 of FIB Technical Report, Bulletin 7, "Corrugated Plastic Ducts for Internal Bonded P ost-Tensioning.” Provide identical test and wear test apparatus with clamp forces that are a function of the number of strands in the duct. Modify the procedure as follows: Do not move the sample along the strand to simulate wear. Ensure the test lasts 7 days. When the test period is complete, remove the duct. Ensure the wall thickness along the strand path is at least 0.06 in [1.5 mm] for ducts with diameters no greater than 3.35 in [85 mm] diameter, and at least 0.08 in [2 mm] for ducts with diameters greater than 3.35 in [85 mm].
8.Corrugated Duct Connections and Fittings Make splices, joints, couplings, and connections to anchorages using devices and methods that produce a smooth interior alignment. Design airtight connections and fittings. The De partment will not allow the use of duct tape to join or repair duct connections. Construct connections and fittings from polyolefin materials containing antioxidant stabilizers in accordance with Subsection 517.02.E, “Inlets, Outlets, Valves, and Plugs.”
517.02 Post -Tensioning
488 (9) Smooth Duct Provide smooth duct manufactured from 100 percent virgin polyethylene resin in accordance with ASTM D 3350. Provide polyethylene resin with a cell class of at least 344464C. Provide resin containing a ntioxidants with an OIT of 40 min in accordance with ASTM D 3895. Manufacture duct with a 17.0 dimension ratio (DR) in accordance with ASTM D 3035 or ASTM F 714, for the manufacturing process used. Provide smooth duct with a pressure rating of 100 psi [0. 69 MPa]. Provide duct manufactured in accordance with ASTM D 3035 or ASTM F 714.
10.External Duct Connections Heat weld to make splices between sections of plastic duct, in accordance with the duct manufacturer’s instructions. Alternatively, provide me chanical couplers as required by the Contract. Provide connections with a pressure rating of at least 100 psi [0.69 MPa], produce a smooth interior alignment, and connect without lips or kinks. Make connections between embedded steel pipe and plastic duct using a mechanical coupler or a circular sleeve made of ethylene propylene deine monomer (EPDM). Provide EPDM with a pressure rating of at least 100 psi [0.69 MPa] and 100 percent quality retention in accordance with ASTM D 1171, ozone chamber exposure m ethod B. Provide EPDM sleeves with a wall thickness of at least ⅜ in [10 mm] and reinforced with at least four sheets of ply -polyester reinforcement. Use a ⅜ in [10 mm] wide power -seated band and Type 316 stainless steel clamps on the boot ends to seal ag ainst grout leakage. Install the band with a seating force from 80 lbf to 120 lbf [356 N to 534 N].
11.Corrugated Ferrous Metal Ducts The Department will not allow the use of corrugated ferrous metal ducts.
12.Shipping and Storage of Ducts Provide duc ts with end caps to seal the ducts from contamination. Ship the ducts in capped and covered bundles. Protect ducts against ultraviolet degradation, crushing, excessive bending, dirt, and corrosive elements during transportation, storage, and handling. B efore incorporating the ducts into the bridge component, keep the end caps in place. Store ducts on a raised platform, in a dry location, protected from the sun, and covered to prevent contamination. Ensure ducts are clean before using. Wash the ducts t o remove contamination if necessary.
13.Flush Water Provide flush water with 0.17 lb/gal [0.02 kg/L] slack lime (calcium hydroxide) or quicklime (calcium oxide).
H.Mechanical Couplers and Heat Shrink Sleeve Requirements Construct mechanical couplers with stainless steel, plastic, or both. To construct plastic couplers, provide plastic resins for plastic ducts as required by the Contract. Make metallic components using ASTM A 240 Type 316 stainless steel. POST -TENSIONIN G 517.02 489 Provide and install heat shrink plastic sleev es sized for the coupled duct. Ensure the sleeves consist of an irradiated and cross -linked, high -density polyethylene backing for external applications and linear -density polyethylene for internal applications. Provide heat shrink sleeves with an adhesi ve layer that withstands 150 °F [66 °C] in accordance with Table 517:2: Install heat shrink sleeves in accordance with the manufacturer’s recommendations.
I.System Test Requirements Assemble systems and test the pressure required by the Contract for each family of post -tensioning systems. Test the largest and smallest assemblies from each family. Include plastic -to-steel pipe connections and segment duct couplers. Table 517:2 Heat Shrink Sleeve Specifications Property Test Method Minimum Requirements Internal Application External Application Minimum fully recovered thickness — 92 mil [2.3 mm] 111 mil [2.8 mm] Peel strength ASTM D 1000 29 pli [50 N/mm] 46 pli [80 N/mm] Softening point ASTM E 28 162 °F [72 °C] 216 °F [102 °C] Lap shear DIN 30 672 M 87 psi [600 kPa] 58 psi [400 kPa] Tensile strength ASTM D 638 2,900 psi [20 MPa] 3,480 psi [24 MPa] Hardness ASTM D 2240 46 Shore D 52 Shore D Water absorption ASTM D 570 <0.05% <0.05% Color — Yellow Black
1.External Duct Systems For external ducts, test the following: The anchorage and its connection to the duct or pipe as required by the Contract for internal duct systems. The grout cap to anchorage fit. The duct and pipe assembly by maintaining a pressure of 150 psi [1.03 MPa] in the system for 3 hr. After conditioning, ensure the assembly sustains a 150 psi [1.03 MPa] internal pressure for 5 min without losing more than 15 psi [103 kPa].
2.Internal Duct Systems Provide an internal duct system assembly in accordance with Chapter 4, Article 4.2, Stage 1 and Stage 2 Testing of the FIB Technical Report, Bulletin 7, “Corrugated Plastic Ducts for Internal Bonded Post -Tensioning.” For tests in precast segmental construction, include one duct coupler for use at the segment joint. Test the couple r by casting the coupler into a two -part concrete test block using match cast techniques. Provide blocks at least 12 in × 12 in × 12 in [300 mm × 300 mm × 300 mm]. After the concrete hardens, separate the blocks and clean bond -breaker materials
517.02 Post -Tensioning
490 from the surface. Using an external apparatus, clamp the blocks together and maintain 40 psi [276 kPa] pressure on the block cross -section throughout the test. Do not apply epoxy during this portion of the test. Pressurize the duct to 5 psi [34 kPa] when the test is complete and lock -off the outside air source. Ensure the assembly loses no more than 2 psi [14 kPa]. Separate the duct coupler blocks from the duct system. Remove the clamping device and place a 1/16 in [1.6 mm] layer of epoxy on the face of both blo cks. Clamp the blocks together with a pressure of 40 psi [276 kPa]. Maintain the pressure on the block cross -section for 24 hr. Demolish the blocks after removing the clamp. Ensure the coupler ducts are intact, epoxy free, and do not show signs of fail ure. Test the grout cap to anchorage seal as required by the Contract. The Department requires one test for systems that use the same anchorages and caps as external systems.
3.Grout Provide grouts in accordance with Subsection 701.18 “Post -Tensioning Grout.” Select the post -tensioning grout based on use. Mix grout with potable water in accordance with Subsection 701.04, “Water.” Maintain grout fluidity in accordance with the gr out manufacturer’s recommendations. Test the fluidity using a flow cone. Submit to the Engineer a copy of the manufacturer’s grout QC Data Sheet for the lot numbers and shipments sent to the job site. Require the supplier to retest and recertify materia ls sent from the manufacturer more than 6 months before use. Store grout in a dry location near the bridge site. If stored in the open, place grout on a raised platform with waterproof covering. Do not store grout on -site for longer than one month.
4.Post -Tensioning Steel Test post -tensioning strand and bar in accordance with Subsection 723.05, “Post -Tensioning Steel Wire.”
J.Testing by the Contractor
1.Tendon Modulus of Elasticity Test Perform a tendon modulus of elasticity test if the Contract requires or the Engineer directs. Bench test two samples of each tendon size to determine modulus of elasticity before stressing the initial tendon. Ensure the bench length between anchorages is at least 40 ft [12 m] for this test and the tendon duct is at least 2 in [50 mm] clear of the tendon. Stress the tendon at an anchor assembly with a load cell at the dead end. Tension the test specimen to 80 percent of ultimate in ten increments. Then detention from 80 percent t o zero in ten decrements. For each increment and decrement, record the gauge pressure, elongations, and load cell force. Note the elongations of the tendon at the ends and the central 30 ft [9 m]. Measure the elongation to within 1/32 in [1 mm]. Correc t the elongations for the actual anchorage set of the dead end. POST -TENSIONING 517.02 491 Calculate the modulus as follows: dlALPE where E = Modulus of elasticity; P = Force in tendon, pound -force [newton]; L = Distance between wedges and dead end wedges, or length in center 30 ft [9 m] of tendon, feet [meter]; A = Cross sectional area of the tendon, square inch [square millimeter]; and dl = Strand elongation for load P. Submit revisions to the Engineer if the bench test varies from the modulus of elasticity on the shop drawings or working drawings by more than 1 percent. If the elongations of the tendons do not meet the Contract required tolerances, the Engineer may require additional tendon modulus of elasticity tests. If the source of post tensioning steel changes during the project, the Engineer will require additional test series or substantiation from previous projects. Ensure the number of tests does not ex ceed two per source. Submit the test apparatus and methods to the Engineer. Conduct tests in the Engineer’s presence.
2.In Place Friction Test Test at least one tendon in each tendon group that performs the same function for tendons longer than 100 ft [30 m]. The Department defines functional tendon groups as cantilever tendons, continuity tendons, draped external tendons, or continuous profiled tendons passing through at least one span. Ensure the selected tendon represents the size and length of the tendon group. The Engineer will not require the in -place friction test on projects with straight tendons in flat or precast voided slabs. Stress the tendon at an anchor assembly with a load cell or a second, certified jack at the assembly dead end. Stres s to 80 percent of ultimate tendon strength in eight increments. At each increment, record the gauge pressure, elongations, and load cell force. Compensate for wedge seating in the live and dead end, friction in the anchorages, wedge plates, and jack. F or long tendons requiring multiple jack pulls and intermediate temporary anchoring, keep an account of the elongation at the jacking end. Investigate, and make detailed recalculations to ensure the final tendon forces are as indicated if the elongations fa ll outside the 5 percent range of the calculated elongations. Do not vary the friction and wobble coefficients by more than 10 percent in reconciling theoretical and actual elongations. As the Engineer approves, correct or compensate for duct misalignment that causes elongation, at no additional cost to the Department.
517.03 Post -Tensioning
492 The Engineer will require one successful friction test for each tendon group. The Engineer may specify additional friction tests if forces and elongations are irreconcilable during stressing operations. Submit the test apparatus types and test methods to the Engineer. Conduct tests in the Engineer’s presence.
3.Tests Reports Required Submit two copies of the test report for the “Tendon Modulus of Elasticity Test” to the Engineer at least 3 0 days before installing the tendon. Submit two copies of the test report for the “In Place Friction Test” to the Engineer within 2 weeks of installation of the test tendon.
4.Application of Test Results Reevaluate the theoretical elongations shown on th e shop drawings or working drawings using the test results for “Tendon Modulus of Elasticity” and “In Place Friction.” Submit revisions to the Engineer.
517.03 Equipment
A.Stressing Equipment Use equipment provided by the supplier of the post -tensioning system.
1.Stressing Jacks and Gauges Equip the jacks with a pressure gauge. Provide a pressure gauge with a dial at least 6 in [150 mm] in diameter.
2.Calibration of Jacks and Gauges Calibrate the jacks and gauges as a unit. Ensure the calibration co nsists of three test cycles with the cylinder extension of the jack in various positions. At each pressure increment, average the forces from the test cycle. Calibrate the equipment in the same configuration intended for the project. Ensure the post -tensioning supplier or an independent laboratory initially calibrates jacks and gauges. Use load cells calibrated within the past 12 months to calibrate stressing equipment. For jack and gauge units, provide certified calibration charts and curves to the En gineer before the start of stressing and every 6 months thereafter, or as directed by the Engineer. Use a master gauge to calibrate equipment after the initial calibration. Give the Engineer the master gauge in a waterproof container to protect the calibr ation gauge during shipment. Provide a quick -attach hydraulic manifold for the master gauge. The Engineer will keep the master gauge for the project duration. Recalibrate using a load cell after any jack repair.
B.Grouting Equipment Provide grouting equ ipment consisting of water -measuring devices, a high -speed shear colloidal mixer, a storage hopper, and a pump with connecting hoses, valves, and pressure gauges. Provide POST -TENSIONING 517.04 493 pumping equipment that can completely fill the post -tensioning duct system uninterru pted at a uniform rate within 30 min in accordance with Subsection 517.04.H(5), “Grout Operations.” Provide vacuum grouting equipment before starting grouting operations.
1.Mixer, Storage Hopper Provide a high -speed, shear, colloidal mixer to continuously mix and produce a homogeneous, stable grout free of lumps and undispersed cement. Provide colloidal grout machinery with a charging and holding tank. Provide a blending tank equipped with a high shear colloidal mixer. Keep the holding tank agitated and at least partially full during the pumping to prevent drawing air into the post -tensioning duct. Add water during the initial mix using a flow meter or calibrated water reservoir with a measuring accuracy within 1 percent of the total water volume.
2.Grout Pumping Equipment Provide positive displacement type pumping equipment that can circulate the grout between operations and maintain pressure on grouted ducts. Fit the ducts with a valve that does not lose pressure when closed. Provide a continuous flow of grout that maintains a discharge pressure of at least 145 psi [1 MPa]. Provide pumps with seals that prevent foreign substances from entering, and loss of grout or water. Ensure the capacity achieves an op timal grouting rate. Place a pressure gauge with a scale reading in increments of no greater than 20 psi [140 kPa] at the duct inlet. If using hoses longer than 100 ft [30 m], place one gauge at the pump and one gauge at the inlet. Provide grout hoses with a diameter and rated pressure capacity compatible with the pump output.
3.Vacuum Grouting Equipment Provide the following during grouting operations for vacuum grouting equipment at the job site: Volumeter for measuring void volume, Vacuum pump with a capacity of at least 10 cfm [0.283 cmm] and equipped with a flow -meter that measures the amount of injected grout, Manual colloidal mixers, dissolvers, or both for voids less than 0.7 ft³ [20 L], and Standard colloidal mixers for voids at least 0.7 ft³ [20 L].
4.Stand -by Equipment Provide a stand -by grout mixer and pump during grouting operations.
517.04 Construction Methods
A.Qualifications Perform post -tensioning field operations under the supervision of a post -tensioning grouting technician with a t least three years experience and is an ASBI Certified Grouting Technician Holder. For
517.04 Post -Tensioning
494 segmental construction, ensure the supervisor and one grouting technician are ASBI Certified Grouting Technician Holders.
B.Shop Drawings Submit shop drawings and wor k plans in accordance with Subsection 105.02, “Plans and Working Drawings.” Include details about the following: Post -tensioning systems, Tendon geometry and locations shown on the Plans in accordance with the limitati ons of the Engineer approved post -tensioning system, Inlets, Outlets, High point outlet inspection, Anchorage inspection, Permanent grout caps, Protection system materials, Application limits, and Method and spacing of duct supports.
C.Protection of Post -tensioning Steel
1.Shipping, Handling and Storage Protect post -tensioning steel against damage and corrosion. The Engineer will reject damaged post -tensioning steel. Inspect reels that contain broken wires, and discard damaged strands. Provide bright and uniformly colored wire with no foreign matter or surface pitting. Package post -tensioning steel in containers to protect them from damage and corrosion during shipping and storage. Place a corrosion inhibitor in the package or in carrier type packagin g material. Provide a corrosion inhibitor with no deleterious effect on the steel, the concrete, or the steel -to-concrete bond strength. Provide corrosion inhibitor carrier packaging. Replace damaged packaging. Ensure the shipping package clearly states that the package contains high -strength post -tensioning steel, the handling care, and information about the corrosion inhibitor. Designate low relaxation strands in accordance with ASTM A 416. The Engineer will reject undesignated strands.
2.During In stallation in the Structure The Engineer will not consider light corrosion cause for rejection of the post -tensioning steel, but will reject any stands with pits or second loss.
D.Placing Ducts
1.General Fasten post -tensioning anchorages, ducts, inlet p ipes, outlet pipes, miscellaneous hardware, reinforcing bars, and embedments where shown on the Plans, shop drawings, working drawings. Minimize the use of duct splices in constructing tendons. POST -TENSIONING 517.04 495 (2) Ducts Fasten internal ducts at intervals no greater than 30 in [750 mm] for steel pipes, 24 in [610 mm] for round plastic duct, and 12 in [300 mm] for flat ducts. Ensure straight external tendon ducts between internal duct connections at anchorages, diaphragms, and deviation saddles. Support external tendon du cts at intermediate locations as shown on the Plans or shop drawings. Ensure smooth and continuous alignments with no lips, kinks, or dents. Check and repair ducts before placing concrete. Seal duct ends, anchorage connections, splices, inlets, and outlets after installation and until grouting completion. Use a plumber’s plug to seal anchorage and duct terminations. Install inlets and outlets with plugs or valves in the closed position. Leave low point outlets open. The Department will not allow the use of duct tape.
3.Splices and Joints The Engineer will consider splices, joints, couplings, inlets, outlets, and valves part of the post -tensioning system. Use shrink -sleeve material to repair ducts. The Department will not allow the use of duct tape to repair or seal duct.
4.Location of Grout Inlets and Outlets Equip grout inlets and outlets with positive shut -off devices. Place grout inlets and outlets in the following positions, or as shown on the Plans or shop drawings: At the top of the tendon an chorage, At the top of the grout cap, At the duct high points if the vertical distance between the highest and lowest point is more than 20 in [0.5 m], At 3 ft [1 m] past duct high points on the upstream and downstream sides, At low points, and At major changes in the cross section of the duct. Extend grout tubes out of the concrete so valves can close.
5.Tolerances Ensure post -tensioning ducts are within the tolerances specified in Table 517:3 ; otherwise, ensure tendons are within ¼ in [6 mm] of the position required by the Contract. Ensure tendon path entrance and exit angles at anchorages, concrete faces, or both are within 3° [5 percent] of the Contract required angle. Ensure smooth transitions. Make angle changes at duct joints no greater than 3° [5 percent]. Place anchorages laterally within ¼ in [6 mm] and along the tendon within 1 in [25 mm] of the Plan positions unless otherwise directed by the Engineer. Maintain minimum coverage of ducts.
517.04 Post -Tensioning
496 Table 517:3 Duct Pos ition Tolerances Tolerances Vertical position, Lateral position, in [mm] in [mm] Horizontal tendons in slabs or in slab regions of larger members ±¼ [±6] ±½ [±13] Longitudinal draped super -structure tendons in webs: Tendon over supports or in middle third of span ±¼ [±6] ±¼ [±6] Tendon in middle half of web depth ±½ [±13] ±½ [±13] Longitudinal, generally horizontal, superstructure tendons in top or bottom of member ±¼ [±6] ±¼ [±6] Horizontal tendons in substructures and foundations ±½ [±13] ±½ [±13] Vertical tendons in webs Longitudinal ±1 [±25] Transverse ±¼ [±6] Vertical tendons in pier shafts ±½ [±13] ±¼ [±6] Center anchorage confinement reinforcement around the duct in spirals, multiple U-shaped bars, or links. Ensure anchorage reinforcement starts within ½ in [13 mm] of the main anchor plate back. Adjust the reinforcement locally as approved by the Engineer if the reinforcement conflicts with post -tensioning duct positions.
6.Internal Duct Pressure Test For tests in precast se gmental construction, include one duct coupler for use at the segment joint. Test the coupler by casting the coupler into a two -part concrete test block using match cast techniques. Provide blocks at least 12 in × 12 in × 12 in [300 mm × 300 mm × 300 mm] . After the concrete hardens, separate the blocks and clean bond -breaker materials from the surface. Using an external apparatus, clamp the blocks together and maintain 40 psi [276 kPa] pressure on the block cross -section throughout the test. Do not app ly epoxy during this portion of the test. Pressure -test internal ducts before casting concrete, except longitudinal ducts, in segments of box girders. Seal the duct and test with compressed air to determine if the duct connections are tight. Pressurize t he duct to 5 psi [34 kPa] and lock -off the outside air source. Record the pressure loss for 5 min. If the duct loses more than 2 psi [14 kPa], repair the leaks as approved by the Engineer. POST -TENSIONING 517.04 497 Separate the duct coupler blocks from the duct system. Remove t he clamping device and place a 1/16 in [1.6 mm] layer of epoxy on the face of both blocks. Clamp the blocks together with a pressure of 40 psi [276 kPa]. Maintain the pressure on the block cross -section for 24 hr. Demolish the blocks after removing the clamp. Ensure the coupler ducts are intact, epoxy free, and do not show signs of failure.
E.Placing Concrete
1.Precautions Place and consolidate concrete without damaging or displacing post -tensioning ducts, anchorage assemblies, splices and connection s, reinforcement, or embedments. Fabricate duct splices to prevent duct kinks during concrete placement. Use mandrels to maintain duct alignment and shape.
2.Proving of Post -Tensioning Ducts Ensure clear, undamaged ducts that can accept post -tensioning tendons, pass a torpedo through the duct after concrete placement. Use a torpedo with the same cross -section as the duct and ¼ in [6 mm] smaller than the duct dimensions. Perform torpedo test in the presence of the Engineer. Do not make deductions to t he torpedo dimensions for tolerances. For straight ducts, use a torpedo at least 2 ft [0.6 m] long. For curved ducts, determine the torpedo length so when both ends touch the outermost wall of the duct, the torpedo clears the innermost wall by ¼ in [6 mm]. Ensure the torpedo passes through the duct without excessive effort or mechanical help. Unless a repair clears the duct, the Engineer will reject ducts if torpedoes cannot pass.
3.Problems and Remedies The Engineer will reject deficient ducts. Make duct repairs as approved by the Engineer.
F.Installing Tendons Do not install permanent tendons if grouting operations cannot be completed in 7 calendar days. Blow oil -free, compressed air through the duct to remove excess water. Push or pull post -tensioning strands through the ducts to make a tendon. Prevent the strands from snagging on lips or joints. Round -off or cap the ends of pushed strands. Ensure a mechanical device does not rotate the strand during the post -tensioning strand installation . Alternatively, assemble strands to form the tendon. Pull the tendon through the duct using a special, steel wire sock. The Department will not allow welding the strand ends together. Round the end of the pre -assembled tendon. Cut strands using an abr asive saw. The Department will not allow flame -cutting. Install permanent tendons after testing as required by the Contract, except for tendons tested for the “In Place Friction Test.”
517.04 Post -Tensioning
498 G. Post -Tensioning Operations
1.General Apply post -tensioning forces after concrete attains the Contract required compressive strength determined by cylinder tests. Stress and grout ducts in the presence of the Department’s Materials Engineer.
2.Stressing Tendons Tension post -tensioning steel with hydraulic jacks to the post -tensioning force shown on the Plans or shop drawings. The Department will not allow the use of monostrand jacks to stress tendons with at least five strands.
a.Maximum Stress at Jacking Ensure the maximum temporary jacking stress in the post -tensi oning steel is no greater than 80 percent of its Contract required ultimate tensile strength. Elongate without overstressing tendons.
b.Initial and Permanent Stresses Anchor the post -tensioning steel at initial stresses that maintain permanent stresses shown on the Plans or shop drawings. Unless the Department’s Bridge Engineer reviews and the Engineer approves otherwise, ensure the initial stress after anchor set is no greater than 70 percent of the Contract required post -tensioning steel ultimate tens ile strength.
c.Stressing Sequence Stress permanent post -tensioning tendons from both ends unless otherwise indicated. Apply the force at one end, then the other, or at both ends simultaneously. The Engineer will allow single end stressing in accordance with the following: Space limitations prohibit double end stressing. The calculated elongation of the post -tensioning steel at the second end is ½ in [13 mm] or less, and wedges are power -seated. Apply single end stressing at alternate ends of paired adja cent post -tensioning tendons to produce a symmetrical force distribution as shown on the Plans. For construction in stages if tendons require stressing before others, install and stress them as shown on the Plans, the shop drawings, or as the Engineer appr oves.
3.Strand Elongations and Agreement with Forces Measure and record tendon forces and post -tensioning tendon elongation. Measure elongations to the nearest 1/16 in [1.6 mm]. Ensure the observed elongation is within 7 percent of the theoretical elong ation for the required tendon force. Check the operation and correct variations as approved by the Engineer before continuing. Do not overstress the tendon to achieve the theoretical elongation. If elongations at the Contract required force are outside t he tolerances, the Engineer may require additional tests for “Tendon Modulus of Elasticity,” “In -Place Friction,” or both in POST -TENSIONING 517.04 499 accordance with Subsection 517.02.J.(1), "Tendon Modulus of Elasticity Test," and Subsection 517.02.J.(2 ), "In Place Friction Test."
4.Friction Submit calculations and show a tendon force diagram, after friction, wobble and anchor set losses. Base the calculations on the expected coefficients and valu es for the post -tensioning system. Show these coefficients and values on the shop drawings. Revise post -tensioning operations so the tendon force equals the final tendon force shown on the Plans if the actual friction varies from the expected friction. Lubricate with graphite as reviewed by the Department’s Materials Engineer and approved by the Engineer when reducing friction. Use lime -treated potable water to flush lubricants from the duct after stressing. Blow dry with oil -free air.
5.Wire Failure s in Post -Tensioning Tendons The Engineer may accept multi -strand post -tensioning tendons with failed wires under the following conditions: The completed structure has a final post -tensioning force of at least 98 percent of the design total. For segmental construction with members post -tensioned together across a common joint face, the post -tensioning force across a mating joint is at least 98 percent of the post -tensioning specified for that mating joint. A tendon has no more than a 5 percent cross -section al area reduction due to wire failure. The Engineer may waive the conditions for acceptance of failed multi -strand tendons, if proposed alternative means of restoring the lost post -tensioning forces are accepted by the Engineer.
6.Cutting of Post -Tension ing Steel Cut post -tensioning steel with an abrasive saw from ¾ in to 1½ in [20 mm to 40 mm] away from the anchoring device. The Department will not allow flame cutting.
7.Record of Stressing Operations Keep a record of the following post -tensioning ope rations for installed tendons: Project number and job piece number, Names of the Contractor and subcontractor; Tendon location, size, and type, Date tendon was first installed in ducts, Reel number for strands and heat number for bars, Tendon cross -section al area, Modulus of elasticity,
517.04 Post -Tensioning
500 Date stressed, and Jack and gauge numbers per tendon end, including the following: Required jacking force, Gauge pressures, Elongations (theoretical and actual), Anchor sets (anticipated and actual), Stressing sequence (i.e. tendons to be stressed before and after, Stressing mode (one end/ two ends/ simultaneous), Witnesses to stressing operation (Contractor and inspector), and Date grouted. Record other relevant information. Provide the Department’s Materials Engineer and the Engineer with a copy of stressing and grouting operations.
8.Duct Pressure Field Test Install grout caps, inlets, and outlets after stressing and before grouting internal or external tendons. Test the tendons with compressed air to determine if duct connections need repairs. Pressurize the tendons to 100 psi [690 kPa] and lock -off the outside air source. Record pressure loss for 5 min. If the duct loses more than 10 psi [69 kPa], repair leaking connections as reviewed by the Department’s Mater ials Engineer and approved by the Engineer.
9.Tendon Protection Install grout caps and seal other tendon openings within 4 hr of stressing. If the Engineer delays tendon acceptance, seal tendon openings and temporarily weatherproof the anchorage open en ds. If tendon contamination occurs, replace the tendon.
H.Grouting Operations
1.Grouting Operations Plan Submit a grouting operations plan to the Engineer for review by the Department’s Materials Engineer at least 6 weeks before scheduled grouting oper ations , submit and approval by the Engineer . The Department’s Materials Engineer must review and the Engineer must approve the plan in writing before permanent structure grouting begins. Ensure the plan addresses the following: Grouting crew and supervis or names and proof of training, Grouting certification, Material types, quantities, and brands for grouting including certifications, Equipment types, capacity in relation to demand and working condition, back -up equipment, and spare parts, General groutin g procedure, Duct pressure test and repair procedures, Method to control the flow rate in ducts, Theoretical grout volume calculations, Mixing and pumping procedures, POST -TENSIONING 517.04 501 Grouting direction, Sequence of inlet and outlet pipe, Procedures for handling blockages, and Procedures for post -grouting repair. Before beginning grouting operations, meet with the grouting crew and the Department’s Materials Engineer. Discuss the grouting operation plan, testing, corrective procedures, and other relevant issues.
2.Grout Inlets and Outlets Ensure air -tight and dirt -free connections from the grout pump hose to inlets. Inspect valves to ensure they open and close properly.
3.Supplies Provide water and compressed air to clear and test the ducts, mix the grout, and pump it before beginning grouting operations. Where water is unavailable through the public water system, provide a water storage tank.
4.Grouting
a.General The Department will not allow grout flushing. Complete grouting operation within 7 calendar days of p ost-tensioning steel installation in the duct. If it is not complete in 7 days, the Engineer will stop the work and instruct the removal of tendons. Every day before beginning grouting operations, test the accuracy of the volume -measuring component of th e vacuum grouting equipment. Use water or grout for testing. Use standard testing devices with 0.5 gal [2 L] and 6.5 gal [25 L] volumes with a 4 oz [0.1 L] or less accuracy. Perform one test with each device. Ensure the results verify the accuracy of t he void volume -measuring component within 1 percent of the test volume. Verify the accuracy of the vacuum grouting equipment volume component within 5 percent of the test volume. Test in the presence of the Department’s Materials Engineer. Grout tendons in accordance with the Grouting Operation Plan. Grout empty ducts.
b.Temperature Limitations Ensure the grout temperature does not exceed 90 °F [32 °C] at the grout inlet. For grouting repairs, ensure the grout temperature does not exceed 85 °F [30 °C] at the grout inlet. Use chilled water, pre -cooled bagged material, or both to maintain the temperature below the specified level. The Engineer will not allow grouting operations when the ambient temperature is 40 °F [4 °C] or less. Check the temperature hourly.
c.Mixing and Pumping Mix the grout with metered water to produce a homogeneous grout. Continuously agitate the grout until grouting completion.
517.04 Post -Tensioning
502 (d) Grout Production Test Maintain fluidity during grouting operations recommended by the grout manu facturer. Use the target fluidity rate established by the manufacturer’s representative and based on weather conditions. Determine grout fluidity using test methods in accordance with Subsection 701.18 , “Post -Tensioni ng Grout.” Perform fluidity tests for grouted tendons. Maintain the water to cementitious ratio. Use grout that tests within the Contract required flow rates. Perform a wick induced bleed test in accordance with Subs ection 701.18 , “Post -Tensioning Grout. ” at the beginning of daily grouting operations. If zero bleed is not achieved at the end of the Contract required time period, delay grouting tendons until operations are adjusted and testing shows that the grout mee ts this requirement.
5.Grout Operations Open grout outlets before beginning grouting operations. Grout tendons in accordance with the Grouting Operations Plan. Pump grout at a rate from 16 ft/min to 50 ft/min [5 m/min to 15 m/min]. Conduct normal grout ing operations at a pressure range from 10 psi to 50 psi [69 kPa to 345 kPa] measured at the grout inlet. Ensure the pumping pressure does not exceed 145 psi [1.0 MPa] at the inlet. Use grout -pumping methods that fill the ducts and encase the steel. Befo re closing the outlet, ensure grout flows from the first and subsequent outlets until residual water or entrapped air is removed. Pump grout through the duct and continuously discharge it at the anchorage and grout cap outlets. Continue pumping until free water and air are discharged, and the grout consistency coming out is the same as the grout consistency going in. Close the anchorage outlet and discharge at least 2 gal [7.5 L] of grout from the grout cap into a clean receptacle. Close the grout cap. Perform fluidity test on tendons immediately after uncontaminated uniform discharge begins. Use the flow cone on the grout discharged from the anchorage outlet. Ensure the measured grout efflux time is at least the efflux time measured at the pump or in a ccordance with Subsection 701.18 , “Post -Tensioning Grout.” Alternatively, check the grout fluidity using the wet density in Subsection 701.18 , “Post -Tensioning Grout.” Ensure the m easured density falls within the values in Subsection 701.18 , “Post -Tensioning Grout.” Ensure the density at the final outlet is greater than or equal to the grout density at the inlet. If the Engineer deems the grout fluidity unacceptable, discharge additional grout from the anchorage outlet and test until grout achieves fluidity. Discard grout used for fluidity tests. Elevate the grout pressure to 75 psi [520 kPa] after bleeding and sealing outlets. Seal the inlet valve and wait 2 min to detect leaks. Fix leaks as reviewed by the Department’s Materials Engineer and approved by the Engineer. If no leaks are present, bleed the pressure to 5 psi [34 kPa]. Wait at least 10 min for entrapped air to flow to the high po ints, increase the pressure, and discharge grout at high -point outlets to eliminate entrapped air or water. Lock 30 psi [207 kPa] in the tendon. Close the inlet, and pump the grout at the next, recently closed, or ready -to-close outlet if the grouting pre ssure exceeds the maximum permitted by the Contract. Maintain the one -way flow. POST -TENSIONING 517.04 503 Do not pump grout into a succeeding outlet from which grout has not flowed. Fit the outlet or inlet with a positive shut -off and pressure gauge for pumping. Stop operations if tendon grouting completion cannot occur using the planned methods approved by the Engineer. Wait 48 hr, then fill the tendon with grout in accordance with Subsection 517.04.H.8, “Post -Grouting Operations and Ins pection.”
6.Vertical Grouting Provide a standpipe for at the upper end of the tendon to store bleed water and grout for vertical tendons . Maintain the grout level above the post -tensioning plate and the highest point of the upper anchorage. Ensure bleed water rises only into the standpipe. Discharge grout and check grout fluidity in accordance with Subsection 517.04.H(5), “Grout Operations.” As grouting is completed, add grout to the standpipe to maintain th e level at the highest point in the upper anchorage. After the grout hardens, remove the standpipe. In the presence of the Department’s Materials Engineer, use an endoscope or probe to visually inspect for voids. Fill voids in the duct using the volumet ric measuring vacuum grouting process. Pump the grout at increasingly higher outlets that were recently closed or are ready to be closed for vertical tendons longer than 100 ft [30 m], or if the grouting pressure exceeds the Contract required pumping press ure. Maintain the one -way flow of grout. Before using an outlet for pumping, allow the grout to flow from each outlet until the air and water disappear.
7.Construction Traffic and Operations Causing Vibrations Eliminate vibrations during grouting and f or 4 hr after completion from any sources such as moving vehicles, jack hammers, compressors, generators, pile driving, soil compaction within 300 ft [91 m] of the ends of the grouted spans.
8.Post -Grouting Operations and Inspection Allow the grout to cu re from 24 hr to 48 hr before removing inlets and outlets. Perform inspections within 1 hr of removal. After the grout cures, remove outlets at anchorages and high points along the tendon. Drill and inspect high points along the tendon including the inl ets or outlets located at the anchorages. Depending on the grout inlet geometry, the Engineer may specify drilling to penetrate the inner surface of the trumpet or duct. Use drilling equipment that automatically shuts -off when it encounters steel. Unles s sounding reveals that grout caps have voids, do not drill into caps. Inspect with endoscopes or probes in the Engineer’s presence. Within 4 hr of completing the inspections, fill duct and anchorage voids using the volumetric measuring vacuum grouting p rocess. Seal and repair anchorage, inlet, and outlet voids from inspection drilling in accordance with Subsection 517.04.I(2), “Repair of Grout Inlets and Outlets.” Backfill with epoxy using an injection tube that extends to the bottom of the holes.
517.04 Post -Tensioning
504 Post grouting inspection of tendons shorter than 150 ft [46 m] may use the following: For the first 20 tendons, inspect outlets at anchors and tendon high points by drilling and probing. If an inspection location cont ains a defect, test until 20 consecutive tendons have no voids. When no defects are present, reduce the inspection frequency to every other tendon. If a defect is found, inspect the last five tendons grouted. Restart the cycle of 100 percent tendon inspe ction. If tendon -grouting operations stop before filling the tendon, drill into the duct and explore the voids with an endoscope. The Engineer will not allow probing. Install grout inlets, and fill the voids with volumetric measuring vacuum grouting equi pment.
9.Grouting Report Submit a signed grouting report to the Engineer within 72 hr of the completion of each grouting operation for review by the Department’s Materials Engineer and approval by the Engineer. Report the theoretical quantity of grout co mpared to the quantity of grout used to fill the duct. Notify the Engineer and the Department’s Materials Engineer of shortages or overages. Include the following information in the report: Tendon identification, Date grouted, Number of days from tendon i nstallation to grouting, Grout type, Injection end and applied grouting pressure, Ratio of actual to theoretical grout quantity, and Summary of problems and corrective action.
I.Forming and Repairs of Holes and Block -Outs
1.Repair of Lifting and Access Holes Repair holes with Magnesium Ammonium Phosphate Concrete in accordance with Subsection 701.21, “Magnesium Ammonium Phosphate Concrete for Concrete Repair.” Within 24 hr before casting the concrete, mechanically clean and roughen the mating concrete surfaces to remove laitance and expose the small aggregate. Blast using grit or water with a nozzle pressure of at least 10,000 psi [69 MPa]. Flush the surface with water and blow dry. Mix, place, and cure the material in accordance with the manufacture’s recommendations. Coat repaired holes, block -outs, and 6 in [150 mm] outside the repair perimeter with methyl methacrylate when deck grooving is complete. App ly and remove excess material as recommended by the manufacturer. As an alternate repair material, use a Type J Epoxy grout compound in accordance with Subsection 701.13 , “Epoxy Resin and Other Adhesives for General Use With Concrete.” POST -TENSIONING 517.04 505 (2) Repair of Grout Inlets and Outlets Use vacuum grouting to repair voids and blockages in accordance with Subsection 517.04.H (5), “Grout Operations.” Place threaded plastic caps in inlet and outl et locations shown on the Plans. Repair inlets and outlets as shown on the Plans using an epoxy grout. Repair cracks in accordance with Section 520, “Structural Concrete Repair by Sealing and Injection.” Repair spalls using Ty pe H epoxy in accordance with Subsection 701.13 , “Epoxy Resin and Other Adhesives for General Use With Concrete.” Prepare the surface as recommended by the manufacturer.
J.Protection of Post -Tensioning Anchorages Prote ct the post -tensioning bar and tendon anchorages as indicated within 7 days of completing the grouting. The Contractor may delay the elastomeric coating application up to 90 days after grouting. Use plastic or stainless steel threaded caps to plug grout inlets and outlets. Use a Type J epoxy grout compound in accordance with Subsection 701.13 “Epoxy Resin and Other Adhesives for General Use With Concrete” to construct pour -backs at anchorages. Remove laitance, grease, curing compounds, surface treatments, coatings, and oil by grit or water -blasting with a nozzle pressure of at least 10,000 psi [69 MPa]. Flush the surface with water and blow -dry. Ensure clean surfaces and no standing water. For disputes, use ACI 503 for substrate testing and develop at least 175 psi [1.2 MPa] tension. Mix and apply epoxy in accordance with the manufacturer’s current standard technical guidelines. Construct pour -backs in leak -proof forms, creating neat lines. Pump the epoxy grout for proper installation. Construct forms to maintain a liquid head and ensure contact with the concrete surface. Use vents so air can escape and ensure forms are completely filled. Coat the pour -backs and grout cap surfaces with an elastomeric coating syste m in accordance with Subsection 737.03 , “Elastomeric Coating System.” Cover these surfaces with a thickness from 30 mil to 45 mil [0.76 mm to 1.14 mm]. Ensure concrete, grout caps, and other substrates are structurall y sound, clean, and dry. Allow concrete to cure at least 28 days. Remove laitance, grease, curing compounds, surface treatments, coatings, and oil by grit or water -blasting with a nozzle pressure of at least 10,000 psi [69 MPa] to establish the anchor pa ttern. Blow the surface with compressed air to remove dust or water. For elastomeric -coated pour -backs receiving a Contract required coating, apply primer approved by the manufacturer over the elastomeric coating before applying the coating. Construct a 2 ft × 4 ft [0.61 m × 1.2 m] concrete test block with a similar texture to the surfaces for coating. Coat a vertical face with the Contract required elastomeric coating system. Determine the number of coats necessary for a coating thickness from 30 mil t o 45 mil [0.76 mm to 1.14 mm] without runs and drips. Mix and apply elastomeric coating in accordance with the manufacturer’s current standard technical specifications. The Department prefers spraying, but will allow rolling. Ensure the coating manufact urer representative supervises the elastomeric coating application on the test block. Ensure personnel that apply the coatings have at least 3 years of experience with similar polyurethane systems. Submit credentials to the Engineer.
517.06 Post -Tensioning
506 517.05 METHOD OF MEASUREMENT The Engineer will measure concrete for post -tensioned cast -in-place concrete structures in accordance with Section 509, “Structural Concrete.” The Engineer will measure reinforcing steel for post -tensioned cast -in-place concrete structures in accordance with Section 511, “Reinforcing Steel for Structures.” The following are post -tensioning steel unit weights: Table 517:4 Post -Tensioning Steel Unit Weights Post -tensioning system, in [mm] Weight per unit length, lb/ft [kg/m] ½ [12.7] diameter 7 wire strand 0.52 [0.77] 3/5 [15.2] diameter 7 wire strand 0.74 [1.1] 1 [26] high strength deformed bar 3.01 [4.48] 1¼ [32] high strength deformed bar 4.39 [6.54] 1⅜ [36] high strength deformed bar 5.56 [8.28] 1¾ [46] high strength deformed bar 9.23 [13.74]
517.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit: POST -TENSIONING Lump Sum Include the following in the contract unit price for Post -Tensioning : Calibration of jacks and gauges; Providing, installing, stressing, and grouting temporary, and permanent post -tensioning tendons; Anchorage assemblies; Hardware; Ducts; Grout and groutin g; Testing and reports; Anchorage protection; Vents; Inlets; Outlets; Epoxy repairs; CONSTRUCTION JOINTS AND EXPANSION DEVICES 518.04 507 Friction control lubricants; Flushing lubricants or contaminants from the ducts; and Endoscope inspection of duct work and grouting. SECTION 518 CONSTRUCTION JOINTS AND EX PANSION DEVICES
518.01 Description
This work consists of fabricating, furnishing, and installing construction joints, water stops, and expansion devices. Provide joints in accordance with the details shown on the Plans, Specifications, Standard Drawings, and recommendations of the manufacturer as directed by the Engineer. Seal the joints as indicated on the Plans to prevent water from seeping through the openings. Design expansion joint systems in accordance with the most recent edition of the AASHTO LRFD Specification, using HL93 truck loading plus Impact, and appropriate load and distribution factors.
518.02 Materials
Provide materials in accordance with the following section and/or subsections: Material: Section or Subsection: Low Modulus Silicone Joint 701.08.F Sealant (Self –Leveling) Rapid Cure Joint Sealant and 701.08.G Elastomeric Mortar Construction Joint and Expansion Joint Sealers 701.08.H Waterstops 733. 08
518.03 Equipment - Vacant
518.04 Construction Methods
A.Construction Joints Place construction joints in accordance with the plans and as directed by the Resident Engineer.
1.Forming and Sealing
a.Saw Cutting Construction Joints Saw-cut the top of the joint after concrete placed on both sides of the joint hardens 1 in [25 mm] deep and ¼ in [6 mm] wide after concrete hardens on both sides of the joint. Seal sawed joints in accordance with Section 415 “Concrete Joint Sealing.” Use a sealant meeting the properties of Subsection 701.08.F, “Low Modulus Silicone Joint Sealant (Self -Leveling).”
Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 496–520 of 935.