602 No measurement or direct payment will be made for the temporary bracing of erected girders, or for preparation of the girder bracing plan, the costs being considered as included in contract items. 602- 1 Description: The work under this section shall consist of prestressing precast and cast -in-place concrete by furnishing, placing and tensioning of prestressing steel in accordance with the details shown on the project plans, and the requirements of the specifications. The work under this section shall also include the furnishing and installation of any appurtenant items necessary for the particular prestressing system to be used, including but not limited to ducts, anchorage assemblies, and grout used for pressure grouting ducts for post -tensioning systems and strand deflection devi ces, such as hold- downs and hold- ups for pretensioning systems. Prestressing for precast concrete items shall be performed by the pretensioning method. Prestressing for cast -in-place concrete structures shall be performed by the post -tensioning method. 602- 2 Materials: 602- 2.01 Reinforcing Steel and Prestressing Steel: Materials furnished for reinforcing steel shall conform to the requirements of Section 1003 of the specifications. Prestressing steel shall be high- tensile steel wire, high- tensile seven- wire strand or high- tensile alloy bars, as shown on the project plans. High -tensile steel wire shall conform to the requirements of AASHTO M 204. High -tensile seven- wire strand shall conform to the requirements of AASHTO M 203 for Grade 270. In addition to the 0.5- inch diameter prestressing steel shown on the project plans, 0.6- inch diameter seven- wire strand may be used for cast -in-place prestressed structures. High -tensile alloy bars shall conform to the req uirements of AASHTO M 275. All prestressing steel shall be satisfactorily protected from damage by abrasion, moisture, rust, or corrosion and shall be free of dirt, rust, oil, TABLE OF CONTENTS INDEX 603 grease, or other deleterious substances when installed and when tensioned. 602- 2.02 Ducts: Duct enclosures for post -tensioning steel shall be rigid galvanized ferrous metal. 602- 2.03 Grout: Grout for post -tensioning tendons shall be a cement grout with a maximum water -cementitious material ratio of 0.45. Adding water to increase grout flowability that has decreased by delayed use of the grout will not be allowed. If approved by the Engineer, cement grout may contain chemical admixtures to improve workability and r educe the water required, reduce bleed, improve pumping properties or entrain air. Chemical admixtures shall conform to the requirements of Subsection 1006- 2.04 of the specifications, except no admixtures containing chlorides, sulfates or nitrates shall be used. Cement grout shall be stored per the manufacturer recommendations. Portland cement shall be Type II conforming to the requirements of Subsection 1006- 2.01 of the specifications. Water shall conform to the requirements of Subsection 1006- 2.02 of the specifications. 602- 2.04 Structural Steel: Material furnished for structural steel shall conform to the requirements of Section 1004 of the specifications. 602- 2.05 Portland Cement Concrete: Portland cement concrete shall conform to the requirements of Section 1006 of the specifications for the class and strength of concrete shown on the project plans. 602- 3 Construction Requirements: 602- 3.01 Shop Drawings:
Shop drawings of the proposed prestressed concrete items shall be submitted in accordance with the requirements of Subsection 105.03 of the specifications. TABLE OF CONTENTS INDEX 604 The drawings shall show the method and procedure of jacking and the type, size, and properties of the strands and number of strands. The size, shapes, dimensions, and concrete cover shall be shown for the reinfor cing steel, including any reinforcing steel to be relocated or added. Calculations shall be submitted showing the elongation of the strands at the time of jacking, the initial forces in the strands, and the final working forces. These calculations may be submitted separately from the drawings, and should also include the latest calibration certifications for the jacking system. In addition, a graph shall be prepared showing the gauge pressure in pounds per square inch and force in thousands of pounds plot ted through the whole range of the tensioning calibration. Not more than two years shall have elapsed between any jack calibrations. In addition to all required working drawings, the contractor shall prepare composite drawings in plan, elevation and secti on which show to scale the relative positions of all items that are to be embedded in the concrete and their embedment depth for the portions of the structure that are to be prestressed. Such embedded items include the prestressing ducts, vents, anchorage reinforcement and hardware, reinforcing steel, anchor bolts, earthquake restrainers, deck joint assemblies, drainage systems, utility conduits, and other such items. Such drawings shall be adequate to ensure that there is no conflict between the planned positions of any embedded items, and that concrete cover is adequate. If during the preparation of such drawings conflicts are discovered, the contractor shall revise its working drawing for one or more of the embedded items, or propose changes in the dimensions of the work as necessary to eliminate the conflicts or provide proper cover. Any such revisions shall be approved by the Engineer before work on an effected item is started. The shop drawings reviewer shall notate their full first and last name and contact phone number on the approved shop drawings. The contractor shall submit a copy of the approved shop drawings to the Structural Materials Testing Section at least 5 working days in advance of the start of production of the precast items. Any changes to shop drawings must be approved by the Engineer. The updated and approved shop drawings shall be sent to the Structural Materials Testing Section at least 24 hours in advance of the start of production.
The shop drawings shall show the strand locations and harping points of the strands. The drawings shall identify the type of finish or surface condition on the top of the precast member. The drawings shall include complete details of the method, materials, and equipment proposed for use in the prestressing operations. Such details shall outline the method and sequence of jacking, complete TABLE OF CONTENTS INDEX 605 details of the prestressing steel, anchoring devices, type of enclosures, block- outs, and all other data pertaining to the post -tensioning system or operations.
The drawings shall show the type, size, and properties of the strands or bars and the anchorage assemblies. The number of strands per tendon shall be shown. Details in addition to those shown on the contract plans shall be included for any additional reinforcing steel required to resist the concrete bursting stresses in the vicinity of the anchorage assemblies. The force or stress diagram shall be shown on the drawings. The sizes, shapes, dimensions, and concrete cover shall be shown for the ducts. Lay- out dimensions for locating the ducts along the tendon path shall not exceed 15- foot intervals. Vent locations and details of the vents shall also be included on the drawings. Calculations shall be submitted showing the stresses in the anchorages and distribution plates. The drawings shall include complete details of the method, materials, and equipment proposed for use in the tensioning operations. Such details shall outline the method and sequence of jacking, complete details of the prestressing steel, anchoring devices, type of enclosures, block- outs, and all other data pertaining to the post -tensioning system or operations. 602- 3.02 Approval of Prestressing Systems: The contractor is responsible for furnishing either basic or special anchorage devices which satisfy the anchor efficiency requirements of the latest edition of AASHTO LRFD Bridge Construction Specifications Article 10.3.2. The anchor efficiency test shall be conducted by an independent testing agency acceptable to the Engineer. A basic anchorage device is an anchorage device meeting the restricted bearing compressive strength limits and the minimum plate stiffness requirements as specified in the latest edition of AASHTO LRFD Bridge Design Specifications Article 5.8.4.4.2. If basic anchorage devices are used, the contractor is responsible for the design of the anchor age device and for determining the required concrete strength. A special anchorage device is an anchorage device whose adequacy must be proven experimentally in the standardized acceptance test and met the acceptance criteria specified in the latest edition of AASHTO LRFD Bridge Construction Specifications, Article 10.3.2.3. If special anchorage devices are used, the contractor is responsible for furnishing anchorage devices that satisfy the acceptance test r equirements of the latest editions of AASHTO LRFD Bridge Design Specifications Article 5.8.4.4.3 and AASHTO LRFD Bridge Construction Specifications Article 10.3.2.3. This acceptance test shall be conducted by an independent TABLE OF CONTENTS INDEX 606 testing agency acceptable to the Engineer. The contractor shall provide records of the acceptance test in conformance with the latest edition of AASHTO LRFD Bridge Construction Specifications Article 10.3.2.3.12 to the Engineer , and shall specify auxiliary and confining reinforcement, minimum edge distance, minimum anchor spacing, and minimum concrete strength at time of stressing required for proper performance of the local zone. Post-tensioning systems which have been approved by the California Department of Transportation (Caltrans) and are listed in the Caltrans Authorized Materials List (AML) are considered an acceptable alternate to the AASHTO testing criteria. A copy of the approval letter from the Caltrans “Division of Engineers Services” , including any details associated with the approval, shall be submitted with the shop drawings by the post -tensioning company. The contractor sh all provide a calibration of the post -tensioning jacking system and shall provide the appropriate control settings for the Department's transducer, electro- hydraulic load cell system by testing the jacking system in a manner that has been pre- approved by t he Engineer. Any deviation from the approved materials and details will not be permitted unless new details are submitted by the contractor and approved in advance of use. The approval of any proposed method, material or equipment shall not operate to reli eve the contractor in any respect of full responsibility for successfully completing the prestressing in accordance with details shown on the project plans and the requirements of these specifications. 602- 3.03 Sampling and Testing: Sampling and testing shall conform to the requirements of AASHTO M 203, AASHTO M 204 and as specified herein. Samples from each size and each heat of prestressing bars, from each manufactured reel of prestressing steel strand, from each coil of prestressing wire, and from each lot of bar couplers to be used shall be furnished for testing. With each sample of prestressing steel wires, bars, or strands furnished for testing, there shall be submitted a Certificate of Compliance, conforming to the requirements of Subsection 106.05 of the specifications, stating the manufacturer's minimum guaranteed ultimate tensile strength of the sample furnished. All materials for testing shall be furnished by the contractor at no additional cost to the Department. The contractor shall have no claim for additional compensation in the event work is delayed awaiting approval of the materials furnished for testing. TABLE OF CONTENTS INDEX 607 All bars of each size from each mill heat, all wire from each coil, and all strand from each manufactured reel to be shipped to the job site shall be assigned an individual lot number and shall be tagged in such a manner that each lot can be accurately identified at the job site. Each lot of anchorage assemblies and bar couplers to be installed at the job site shall be likewise id entified. All unidentified prestressing steel, anchorage assemblies or bar couplers recovered at the job site will be rejected. 602- 3.04 Anchorage and Distribution for Post -Tensioned Structures: All post -tensioned prestressing steel shall be secured at the ends by means of approved permanent type anchoring devices. The load from the anchoring device shall be distributed to the concrete by means of approved devices that effectively distributes the load to the concrete by meeting the requirements of a basic anchorage device or a special anchorage device. Both basic and special anchorage devices must also meet the following anchor efficiency test criteria: the anchorage device shall hold the prestressing steel without exceeding anticipated set at a load producing a stress of not less than 95 percent of the guaranteed minimum tensile strength of the prestressing steel. 602- 3.05 Duct Installation for Post -Tensioned Structures: Duct enclosures for prestressing steel shall be mortar -tight and accurately placed at the locations shown on the project plans or approved by the Engineer. Ducts shall be fabricated with either welded or interlocked seams. Galvanizing of the welded seam is not required. Ducts shall have sufficient strength to maintain their correct alignment during placing of concrete. Joints between sections of duct shall be positive metallic connections which do not result in angle changes at the joints. Waterproof tape shall be used at all connections. Transition couplings connecting ducts to anchoring devices need not be galvanized. All ducts or anchorage assemblies shall be provided with pipes or other suitable connections for the injection of grout after prestressing. Ducts for prestressing steel shall be securely fastened in place to prevent movement and displacement during concreting. Ducts shall be placed within ± 1/4 inch of the dimensions shown on the approved shop drawings. After installation in the forms, the ends of ducts shall be covered at all times as necessary to prevent the entry of water or debris. If prestressing steel is to be installed after the concrete has been placed, TABLE OF CONTENTS INDEX 608 the contractor shall demonstrate to the satisfaction of the Engineer that the ducts are free of water and debris immediately prior to installation of the steel. Prior to placing forms for closing slabs of box girder cells, the contractor shall demonstrate to the satisfaction of the Engineer that all ducts are unobstructed and if the pr estressing reinforcement has been placed, that the steel is free and unbonded in the duct. Prior to placing the forms for closing slabs of box girder cells, the contractor shall demonstrate to the Engineer, by aerostatic or hydrostatic tests, that the duct system does not permit leakage of grout into the box girder cells. For ducts completely encased in concrete, such tests shall be performed with a charging pressure of 40 pounds per square inch. Once the charging pressure is attained, the mechanical shut -off valve shall be closed for a period of not less than five minutes. A retained pressure of 20 pounds per square inch, or greater, after five minutes, will be considered an indication of acceptable performance. Ducts not completely encased in concrete shall have the exposed areas sealed with an epoxy compound and then pressure tested to 20 pounds per square inch for five minutes. A retained pressure of 10 pounds per square inch or greater, after five minutes, will be considered an indication of acceptable performance. All leaks shall be repaired and the ducts retested prior to placing the forms. If, after two attempts to repair leaks, the ducts still do not comply with the above performance requirements, the Engineer may accept the ducts if the Engi neer is satisfied that no significant leakage of grout will occur. After completing each aerostatic or hydrostatic test, the ducts shall be blown dry with oil -free compressed air. 602- 3.06 Prestressing:
Unless other wise shown on the project plans, the stresses in the prestressing steel shall not exceed those specified in the current edition of the AASHTO LRFD Bridge Design Specifications. However, when low relaxation strands are used in post -tensioning cast -in-place concrete, the jacking force shall not exceed 78 percent of the minimum ultimate tensile strength of the prestressing steel. Working force will be considered as the force remaining in the prestressing steel after all losses, including creep and shrinkage of concrete, elastic compression of concrete, losses in prestressing steel due to sequence of stressing, friction, and all other losses peculiar to the method or system of prestressing have taken place or have been provided for. TABLE OF CONTENTS INDEX 609 All prestressing steel shall be tensioned with hydraulic jacks so that the force in the prestressing steel shall not be less than the value shown on the project plans. Each jack used shall be equipped with either a pressure gauge or a load cell to determine the jacking force. All jacks and gauges shall be calibrated as a unit and shall be accompanied by a certified cali bration chart. All gauges shall be either a reading dial at least 6 inches in diameter or a digital display indicator. The increments shown on the reading dial gauge shall not exceed 2 percent of the jacking force. The digital display indicator shall be readable by normal vision at a distance greater than 10 feet. All gauges shall show a load accuracy of 1 percent of the load, from 1 percent to 100 percent of the capacity of the gauge. The certified calibration charts for the hydraulic jacks and pressure gauges may be checked before and during jacking operations with Department -furnished load cells. If the certified calibration is found to be in error, the operation shall be immediately discontinued until a new certified calibration is performed by the contractor. Welding or a welding ground shall not be done near prestressing steel and ducts. Welding near prestressed work shall be done only if specified on the project plans or directed by the Engineer. The tensioning process shall be so conducted that t he force being applied and the elongation of the prestressing steel may be measured at all times. The actual elongation obtained from the calibrated force value shall be compared with the theoretical calculated elongation. If the actual measured elongati on differs by more than 5 percent of the theoretical calculated elongation, the entire operation shall be carefully checked and the source of the error determined and corrected before proceeding with the tensioning. A record of the prestressing force and elongations shall be kept at all times and submitted to the Engineer for approval.
The tensioning force in pretensioned strands shall not be transferred to the member until tests on cylinder specimens made and cured under the same conditions as the member indicates the required compressive release strength has been attained. This shall constitute the end of the curing period. The release of the strands shall be from one or both ends of the casting bed depending upon which method produces the least movement of items in the casting bed and the least horizontal eccentricity of the initial prestressing force in the member. All pretensioned items shall be tensioned either by single strand or multiple strand jacks. Stressing gauges, jacks, and other related equipment shall be calibrated annually or more frequently if necessary. TABLE OF CONTENTS INDEX 610 The manufacturer shall supply calibration reports when requested by the Department. No more than one splice chuck shall be used on a cable strand. Splice chucks will not be allowed within the member. Strands to be spliced shall have the same lay or direction of twist. When multiple cable tensioning is employed, the use of splice chucks shall be limited to 10 percent of the cable strand to be tensioned or all cable strands to be tensioned. Each plant shall be required to supply load cells to measure force on each production bed as directed by the Engineer. This may include load cells placed on cable strand between chucks and the dead men (anchorage bulkheads) on both straight and harped strands, at both the live and dead ends. Load cells shall be used as necessary to monitor the gauge pressure during stressing operations, abutment rotation, and bed shortening. Load cells shall be calibrated annually or more frequently if necessary. If loss of force is suspected, load cells shall be placed between the stressing chucks and the anchorage on an everyday basis to verify stressing forces for each production bed. When all losses have been verified for each production bed and stressing values are within tolerances, load cells shall be used daily as needed to monitor stressing forces of each stressing jack. Periodically, load cells shall be placed between strand chucks and anchorage as verification. All cable strands shall be placed within 1/4 inch of the strand locations indicated on the approved shop drawings. All hold downs and cable locations shall be clearly marked on the approved drawings. At no time shall a cable strand which has been previously stressed and used outside a Precast/Prestress prod uct or member be used at a later time within another Precast/Prestress member. Cable strand shall be free of deleterious materials such as release agents, oils, grease, dirt, mud, or other foreign matters. Any cable found in such condition shall be cleaned or removed, based on the inspector’s observations. Jacking the prestressing steel shall be performed in two increments. An initial tension shall be applied to the strands to straighten them, to eliminate slack and provide a starting or reference point for measuring elongation. The final tension shall the n be applied and elongation of strands measured. Elongations shall be measured to the nearest 1/8 inch. No more than one broken wire will be permitted in a single strand. Anchoring devices shall be capable of holding strands with a minimum of differential slippage. Stringing of following lengths of strand incorporating points previously gripped within lengths to be stressed will not be permitted. Any rotation of the strand shall be limited to not more than one revolution per 100 feet of exposed strand. TABLE OF CONTENTS INDEX 611 Harped strand shall be tensioned from both the live and dead ends, except for the following:
vertically displaced into the correct height. Load cells shall be used to ver ify the force; and
At no time shall stressing operations exceed 80 percent of the minimum ultimate tensile strength for the cable strand as listed in the approved shop drawings. Initial stressi ng force shall not exceed 25 percent of the final force. De-tensioning of cables shall not be performed until concrete test cylinders indicate release strength has been attained. De- tensioning shall be performed in a manner that keeps the prestressing for ces nearly symmetrical about the vertical axis of the product and:
forms, inserts and hold downs;
by using accelerated curing such as steam or radiant heat; and
curing and the removal of forms, curing blankets, tarps, or plastic coverings while the concrete is warm and moist. When ordered by the Engineer, prestressing strands in precast items , if tensioned individually, shall be checked by the contractor for loss of force not more than 3 hours prior to placing concrete for the items . The method and equipment for checking the loss of force shall be subject to approval by the Engineer. All strands which show a loss of prestress in excess of 3 percent shall be retensioned to the original jacking force. When concrete has not been placed within 72 hours of the t ensioning of the prestressing strands, retensioning of all strands will be required prior to placing of the concrete. TABLE OF CONTENTS INDEX 612
Prestressing steel for post -tensioning, which is installed in structures prior to placing and curing of the concrete, shall be continuously protected against rust or other corrosion until gr outed by means of an approved corrosion inhibitor placed in the ducts or applied to the steel in the duct. If the strands are in the duct at the time concrete is placed, no tensioning will be allowed until it is demonstrated to the satisfaction of the Eng ineer that the prestressing strands are free and unbonded in the duct. When prestressing steel for post -tensioning is installed in the ducts after completion of concrete curing, and if stressing and grouting are completed within 10 days after the installation of the prestressing steel, rust which may form during the 10 days will not be cause for rej ection of the steel. Except as herein provided, cast -in-place concrete shall not be prestressed until at least seven days after the last concrete has been placed in the structure to be prestressed and until the compressive strength of all placed concrete, has reached the required strength for jacking. Prestressing steel shall be tensioned by jacking from each end of the tendon for continuous structures unless otherwise noted on the project plans. Such jacking of both ends need not be done simultaneously, unless specifically indicated on the plans or in the Special Provisions. Prestressing steel may be tensioned by jacking from one end only for simple span structures. Should the contractor elect to furnish an anchoring device of a type which is sufficiently large and which is used in conjunction with a steel grillage embedded in the concrete that effectively distributes the compressive stresses to the concrete, the steel distribution plates or assemblies may be omitted. Where the end of a post -tensioned assembly is not covered by concrete, the anchoring devices shall be recessed so that the ends of the prestressing steel and all parts of the anchoring devices are at least 2 inches inside of the end surface of the items , unless a greater embedment is shown on the project plans. Following post -tensioning, the recesses shall be filled with concrete for the structure and finished flush. At no time will a cutting torch be allowed for cutting prestressing steel for cast -in-place pr estressed structures. TABLE OF CONTENTS INDEX 613 602- 3.07 Grouting of Post -Tensioned Members: Post -tensioned prestressing steel shall be bonded to the concrete by completely fil ling the entire void space between the duct and the tendon with grout. All of the tendons in a cast -in-place concrete structure shall have been fully tensioned and anchored prior to any grouting operation. The grout shall be mixed in mechanical mixing equi pment of a type that produces uniform and thoroughly mixed grout. Water shall be first added to the mixer followed by cement. Retempering of grout will not be permitted. All grout shall pass through a screen with 1/8- inch maximum clear openings prior to being placed in the grouting equipment and shall be continuously agitated until it is pumped. The quality of the grout shall be determined by the Engineer in accordance with the requirements of Arizona Test Method 311. The efflux time of a grout sample immediately after mixing shall be not less than 11 seconds. The maximum temperature of the grout shall be 90 degrees F and the minimum 50 degrees F. Grouting equipment shall be capable of grouting at a pressure of at least 150 pounds per square inch and shall be furnished with a pressur e gauge having a full -scale reading of not more than 300 pounds per square inch. Maximum grouting pressure shall not exceed 250 pounds per square inch. Standby flushing equipment capable of developing a pumping pressure of 250 pounds per square inch and of sufficient capacity to flush out any partially grouted ducts shall be provided and available at the job site. Equipment capable of providing dry, oil free compressed air for removing water from the ducts shall also be available at the site. All ducts sh all be clean and free of deleterious materials that would impair bonding of the grout or interfere with grouting procedures. Compressed air used to blow through the ducts shall be oil -free and water -free . Immediately prior to grouting, the contractor shall check all inlet and outlet pipes to verify they are capable of accepting grout injection. Grout injection pipes shall be fitted with positive mechanical shutoff valves. Ejection pipes shall be fitted with valves capable of withstanding the pumping pressures. Valves shall not be removed or opened until the day following the grouting operation, unless otherwise approved by the Engineer. Draped tendons exceeding 400 feet shall be vented at all high points. Grout vents shall be made of rigid tubing or pipe with threaded fittings and shutoff valves. TABLE OF CONTENTS INDEX 614 Grout shall be injected at the low end of the duct and continuously wasted at the outlet until no visible slugs of water or air are ejected. The outlet pipe shall then be closed and the duct shall then be pressurized. The pressurized duct shall maintain a minimum pressure of 75 pounds per square inch for a minimum time of one minute. The valve at the inlet shall then be closed while maintaining this minimum pressure. If complete grouting of the duct cannot be achieved or the grouting operation is interrupted, the contractor shall flush the grout out of the duct immediately with water. When hot weather conditions would contribute to quick stiffening of the grout, the grout shall be cooled by approved methods as necessary to prevent blockages during pumping operations. The use of an approved chemical admixture should also be considered for increasing the pumping efficiency and/or time of set. When freezing weather conditions are anticipated during and following the placement of grout, the contractor shall provide adequate means to protect the grout in the ducts from damage by freezing. Vibration from contractor controlled equipment shall be eliminated within 100 feet during grouti ng and for a period of 24 hours after grouting. The surfaces of concrete against which concrete encasement over anchorage assemblies is to be placed shall be abrasive blast cleaned and aggregate exposed after grouting of the ducts has been completed. 602- 3.08 Finishing Precast Concrete: The finishing of precast concrete bridge structures shall comply with the requirements of Subsection 601- 3.05 of the specifications. In addition, those exterior surfaces of exterior bridge structures normally in the view of vehicular or pedestrian traffic shall be finished in accordance with the requirements for a Class II Finish. Unless otherwise specified on the plans, the top surface of I -beams, box beams, and flat slabs shall be roughened with a hand tine rake while the concrete is still plastic. All projecting strands that are not scheduled to remain for future embedment shall be cut off at the surface of the concrete. Strands that are to remain shall be cut and bent to the dimensions shown on the plans. If the end of the precast bridge member is not embedded in cast - in-place concrete, then all the strands shall be cut or ground flush with the surface of the concrete and thoroughly coated with a bitumastic type sealant. Exposed uncoated reinforcing bars and strand shall be cleaned of concrete laitance and other foreign materials. If concrete laitance is TABLE OF CONTENTS INDEX 615 allowed to harden and other foreign materials are allowed to remain on the bars, then abrasive blast methods shall be conducted for cleaning. The cleaning of exposed epoxy- coated reinforcing steel shall be limited to methods not damaging to the coating, the actual cleaning to be completed while the concrete laitance are still plastic. Any damage done to the epoxy coating shall be repaired in accordance with Subsection 605- 3.03(B) of the specifications. The work described in this subsection shall be accomplished in the production yard of the precast manufacturer. Precast bridge structures will be approved for transportation based on the following criteria; the member has been inspected and approved by the Department, a minimum of 14 days have passed since concrete placement, and the 28- day compressive strength requirement has been met. 602- 4 Method of Measurement: No measurement or direct payment will be made for prestressing precast concrete, the cost bei ng considered as included in the cost of precast concrete items. Prestressing concrete in cast -in-place structures will be measured by the approximate station for which a lump sum item is listed in the bidding schedule for such work. 602- 5 Basis of Payment: Prestressing cast -in-place concrete will be paid at the contract lump sum price, complete in place. Furnishing and placing reinforcement not shown on the project plans and required only for anchorage zone recesses, blocks, duct ties, and grillage assemblies, as recommended by the post -tensioning system used, shall be considered as included in the lump sum price paid for prestressing cast -in-place concrete. Furnishing and placing concrete used in girder web flares and for concrete used in external anchorage blocks, including cover of distribution plates, shall be considered as included in the contract lump sum price paid for prestressing cast -in-place concrete. Partial payments may be made in accordance with the provisions of Subsection 109.07 of the specifications. Payments will be made on the basis of the following:
TABLE OF CONTENTS INDEX