809Precast/Prestressed Structure Concrete Masonry

— PRECAST/PRESTRESSED STRUCTURE CONCRETE MASONRY

809.01DESCRIPTION

This work includes providing precast, prestressed concrete elements, both pre -tensioned and post-tensioned, and precast concrete elements at the required locations. General. Ensure that p restressed concrete structural elements are manufactured according to the Prestressed Concrete Institute Manual for Quality Control for Plants and Production of Precast and Prestressed Concrete Products, MNL 116, currently adopted edition. Ensure that precast and prestressed concrete elements are manufactured in a facility that is certified by the Precast/Prestressed Concrete Institute (PCI) or the National Precast Concrete Association (NPCA). Out-of-State Inspection Services. The Department will conduct inspections of the plant and laboratory and will witness the trial batches, full-time acceptance testing, and part-time Independent Assurance sampling and testing (as defined in the Department ’s Materials Master Schedule of Testing) for all phases of production, repair of products, loading, shipping, and other related operations, including travel days as deemed necessary by the Engineer. Inspection service days or part thereof will also include weekends, holidays, and shutdowns due to the Contractor’s inability to produce.

809.02MATERIALS

Concrete. Provide a concrete design mix to produce the strength and other characteristics according to SECTION 601. Steel. Except as noted herein, ensure that reinforcing steel conforms to SECTION 810.

requirements: ● Provide galvanized or plastic chairs or other devices capable of supporting the loads without deformations to ensure the proper placement of steel items all as approved by the Engineer. ● Provide prestressing steel according to Subsection M05.04. ● Provide bearing plates, if required, according to SECTION M05. ● For c oated steel, repair all breaks with a coating according to the manufacturer ’s recommendations before placement in the form. Use c oated tie wires with coated rebars.

Part 800 — Bridge Structures August 2025

● The Engineer will approve in writing any additional prestressing steel strands , reinforcing steel, wire mesh, and any other necessary materials.

809.03CONSTRUCTION METHODS

Equipment Checks and Calibration. Provide a calibration certificate indicating the load calibration of each gauge and hydraulic jack combination used for tensioning. Ensure that the gauge has marked divisions of 2 percent of the final tensioning force that are easily readable at the initial and final tensioning force. C alibrate each combination gauge and hydraulic jack every six months. Recalibrate any rams after repair, such as replacing the seals or changing the length of the hydraulic lines with a load cell. Provide a compressive strength testing machine conforming to AASHTO T22 Specifications. Produce, store , and cap the specimens according to AASHTO Specifications. Calibrate t he compressive strength testing machine at least once every six months and provide the calibration certificate to the Engineer. Provide the Engineer with full access to the compressive testing machine. Inspection of the Plant and Facilities. The Engineer will inspect the f abrication of all units. Provide a plant laboratory conforming to SECTION 930. The Contractor may perform work in the absence of the Engineer with the Engineer’s prior written approval. Inform the Engineer of the day-to-day scheduling of operations. Provide the Engineer free access throughout the fabrication plant to observe that the work being performed conforms to the Contract Documents. Notify the Engineer before: • Commencement of production: 30 days • Recommencement of work after a suspension of 48 hours or more: ○ A minimum of two days when the Engineer is on site ○ A minimum of two weeks when the Engineer is not on site • Unit shipping: ○ A minimum of two days when the Engineer is on site ○ A minimum of two weeks when the Engineer is not on site Shop Drawings and Concrete Forms.

● Contract Plans. Plans that accompany the Contract documents are designated as Contract Plans. These are not considered Shop Drawings. ● Shop Drawings. Submit Shop Drawings to the Engineer for approval according to Subsection 105.02. Modify the dimensions of prestressed units to compensate for elastic shortening, shrinkage, grade corrections, and other factors that make in- process fabricating dimensions different from those shown on the Contract Plans. Do

Part 800 — Bridge Structures August 2025

800-70SECTION 809 — PRECAST/PRESTRESSED STRUCTURE CONCRETE MASONRY

not perform any fabrication until the Shop Drawings have been approved by the Engineer and copies of the approved Shop Drawings have been submitted to the Engineer. ○ Information Required on Shop Drawings. Provide Shop Drawings that include the following information: + Plan layout of structure indicating the element identification assigned to each precast/prestressed unit + A tensioning and detensioning schedule for all prestressed products to be fabricated + Complete details, including: − anticipated initial and shipping cambers − tensioning force (initial and final) − concrete compressive strength for stripping of forms (for precast elements − load transfer strength for prestressed elements − 28-day strength for shipping), class of concrete, and type and location of lifting devices + All deviations from the precast/prestressed unit details shown on the Plans + For drawings and other relevant documentation for prestressed concrete elements, refer to “Prestressed Concrete Notes” indicated on the Plans ○ Information Required with Shop Drawings. Provide the following information with the Shop Drawings: + Calculations of prestressing steel strand elongation for each unique casting length (grip to grip) + The location of all dunnage and pick up points ● Approval. Submission for the Engineer ’s approval in writing of a detailed plan for curing the precast/prestressed elements. Provide a detailed plan that includes the following: ○ Curing method ○ Provision for enclosures, indicating method of holding down enclosure safely in place ○ Heating devices, types, and location around the structure

Part 800 — Bridge Structures August 2025

○ Method of monitoring time/temperature of hardened concrete ○ Backup systems as required

Engineer will approve in writing all forms before placing concrete.

the tolerances in the current edition of PCI MNL 116 and the approved Shop Drawings , including: ● Lengths and widths ● Cable locations ● Position of weld plates and bearing plates ● Bulkhead locations and dimensions ● Blockout locations ● Post tensioning duct locations ● Keyway dimensions ● Dimensions on skewed or battered ends ● Expansion duct locations ● Insert locations ● Fixed and expansion sleeve locations ● Locations of voids ● Location of drip grooves ● Sizes of voids

with a 1-in. diameter vent located at each end of the void. Vent a ll voids after removing the concrete element from the form. Prestressing Steel. Before installation in the units, ensure that the prestressing steel is free of rust, frost, dirt, oil, paint, corrosion, or any foreign material that may prevent bonding between the steel and the concrete. The Engineer will reject any prestressing steel that has sustained physical damage. The development of pitting or corrosion impacts (other than rust stain) will be cause for rejection as determined by the Engineer. Examine prestressing steel that is exhibiting rust stains before its placement in the forms to determine if pitting exists. Replace any coil that contains broken prestressing or post tensioning steel strands. Do not splice prestressing steel strands inside the casting form. Splicing of strands outside the casting form may be allowed only with prior written approval of the Engineer. Do not t ack weld the bar reinforcement. Place and fasten all steel reinforcement according to Subsection 810.03.5. Furnish a manufacturer’s Certificate of Compliance and a mill test report per size, heat number, source, and load for all prestressing steel strands. The Engineer may obtain strand steel samples for verification testing.

Part 800 — Bridge Structures August 2025

800-72SECTION 809 — PRECAST/PRESTRESSED STRUCTURE CONCRETE MASONRY

See SECTION 810 for reinforcing steel. Tensioning of Prestressing Strands. Tension the prestressing elements to provide the required prestress to conform to the current edition of PCI MNL 116. Ensure that all strands of a prestressed member are free from kinks or twists before initiating tensioning operations. Do not allow any unwinding of the strand in excess of one turn after tensioning operations are begun. Ensure that all strands are tensioned to 20 percent of the final jacking force before elongation readings are started. Ensure that the equipment for producing the initial tensioning load provides a means for accurately measuring the force. When the initial tensioning load is applied by pressure jacks, equip the jack with a proper gauging system for the initial force. Apply t he pre- designated initial force to each strand. Use t his load as the starting point for measuring additional tensioning for tension determination by the elongation method. When comparing theoretical gauge and actual gauge readings, and theoretical elongations and actual elongations, comply with the requirements of the currently adopted edition of PCI MNL 116. In the elongation computation, account for strand anchorage slippage, horizontal movement of abutments, bed shortening , and any change in temperature of the prestressing steel between tensioning and the time when concrete takes its initial set , if the change is expected to exceed 30°F. Do not perform the final pretensioning at temperatures below 20°F. Stress the draped strands no higher than the required design stress minus the stress increase in the strand from forcing it into a draped profile. If the strands are tensioned in their draped position, support the strands by rollers at each point of change in direction. Ensure that t he holdup rollers between members and at the ends of the members have either bronze bushings or roller bearings that are free running and kept well lubricated. Ensure that rollers at the hold-down points are free running and of a type that produces a minimum amount of friction. If the load for a draped strand, as determined by elongation measurements, exceeds 5 percent less than that indicated by the jack gauges, tension the strand from both ends of the bed. Ensure that the load as computed from the sum of elongation at both ends agrees within 5 percent of that indicated by jack gauges. There may be a discrepancy in the indicated stress between jack gauge pressure and elongation. If yes, ensure that the load used produces a slight overstress rather than understress. When a discrepancy between gauge and elongation measurements of more than 5 percent occurs, check the entire operation and determine and correct the source of error before proceeding further. The Engineer may require the use of a load cell to check the applied load. Calibrate t he load cell at least once every six months or more frequently when deemed necessary by the Engineer. Check prestressing steel strands in pretensioned members, if tensioned individually or in groups, for loss of prestress not more than three hours before placing concrete. The Engineer will approve the method and equipment for checking the loss of prestress. Retension all strands that show a relaxation loss of prestress in excess of 3 percent to the designed final jacking force.

Part 800 — Bridge Structures August 2025

When stressing grouped strands simultaneously, first bring each tendon to initial tensioning load. Apply the final tensioning load to the group using a procedure approved by the Engineer. During tensioning of any strand, conduct the process so that the applied load and the elongation of the strand may be measured at all times. Check any prestressed strand that has been tensioned for over 48 hours without the placement of concrete for elongation or loss of stress before placing concrete. If losses occur, detension the strands and then retension according to the design loading requirements. Handling and Placing Concrete. Do not place concrete without the Engineer ’s written approval. Handle and place c oncrete according to SECTIONS 601 and 808. Convey and place concrete without segregation. Do not drop the concrete mixture from a height greater than one foot above the top of the forms. Deposit the concrete in its final position in each part of the form. Consolidate the fresh concrete in place according to PCI MNL 116 Division 4.17. Finishing. After all concrete has been placed and compacted as required under Subsection 809.03.6, magnesium float finish the tops of units. To ensure production of well-formed concrete elements with an overall pleasing appearance, ensure that all concrete surfaces are true and even and free from rough, open , or honeycombed areas, depressions, air pockets , or projections. Finish all exposed surfaces by bagging or as otherwise indicated. Curing. Ensure that curing conforms to PCI MNL 116, Divisions 4.18, 4.19, and 4.20. Cure precast concrete members for not less than seven days in conformance with the water method, steam curing, or radiant heat at the option of the Contractor. Ensure thats team curing for precast members conforms to the following provisions: • After placement of the concrete, hold members for a minimum four -hour presteaming period. If the ambient air temperature is below 50°F, apply steam during the presteaming period to hold the air surrounding the member at a temperature between 50°F and 90°F. • To prevent moisture loss on exposed surfaces during the presteaming period, cover the members as soon as possible after casting, or keep the exposed surfaces wet by fog spray or wet blankets. • Allow e nclosures for steam curing free circulation of steam about the member , and construct the enclosure to contain the live steam with a minimum moisture loss. The use of tarpaulins or similar flexible covers will be permitted, if the covers remain in good repair and are secured to prevent the loss of steam and moisture.

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800-74SECTION 809 — PRECAST/PRESTRESSED STRUCTURE CONCRETE MASONRY

• Ensure that steam at the jets is low pressure and in a saturated condition. Do not permit steam jets to impinge directly on the concrete, test cylinders, or forms. During application of the steam, ensure that the temperature rise within the enclosure does not exceed 40°F per hour. Ensure that the curing temperature throughout the enclosure does not exceed 150°F and is maintained at a constant level for a sufficient time necessary to develop the required transfer strength. Cover control cylinders to prevent moisture loss, and place the cylinders where temperature is representative of the average temperature of the enclosure. • Provide calibrated temperature recording devices that will provide an accurate continuous permanent record of the curing temperature. Use a minimum of one temperature recording device per 100 ft of continuous bed length for checking the temperature. • Once the minimum transfer compressive strength is achieved, detension members in tension immediately after the termination of steam curing while the concrete and forms are still warm, and ensure that the temperature under the enclosure maintains above 60OF until the stress is transferred to the concrete. • The initial curing of precast concrete will be considered complete once the specified transfer strength is verified by compressive strength test results. • Radiant heat may be applied by pipes circulating steam, hot oil or hot water, or electric heating elements. Perform radiant heat curing under a suitable enclosure to contain the heat and moisture loss, and minimize heat loss by covering all exposed concrete surfaces with plastic sheeting. If the Contractor proposes to cure by any other method, the Engineer must approve the method and its details. Testing.

Assurance sampling and testing conforms to SECTION 601, as modified herein.

to SECTION 601 and according to the following provisions: ● Field cure the Quality Control cylinders under the same curing conditions as the precast/prestressed element. Furnish the cylinder molds for all compressive test specimens. ● Cast Quality Control cylinders and test in the presence of the Engineer. ● Place all cylinders within 15 ft of each end of the casting bed or as determined by the Engineer. ● Test one cylinder from each location in immediate succession to verify form stripping (precast), stress transfer (prestressed), and 28-day strengths (shipping).

Part 800 — Bridge Structures August 2025

● Do not ship any structure from the plant to the P roject site unless it has obtained the minimum 28 -day compressive strength. Do not ship without the RIDOT Materials inspection stamp or other documented approval by the Engineer.

Transfer of Prestress. Accomplish the transfer of prestress in the presence of the Engineer and according to the approved detensioning schedule and as soon as the transfer strength is achieved and verified. Provide a detensioning schedule that includes the following: • The order of detensioning • A provision that each strand is detensioned at each end and/or between each element At the end of each prestressed element, chip back the concrete surrounding the individual strands to sound material to a depth of between ¾ in. to 1 in. Cut back the strands to the same depth. Square off the edges to avoid producing a feathered edge. R emove all dirt and residue that is not firmly bonded to the metal or concrete surfaces. Fill the ensuing void, including the end of the strand, with an approved non- shrink grout. Finish the surface to be flush with that of the plane surface of the product. Handling. Remove all products from the forms in the presence of the Engineer. Provide adequate notice to the Engineer to allow witnessing of the removal operation. Ensure that precast/prestressed members are not damaged during handling and moving. Transport precast girders and slabs in an upright position. Ensure that the points of support and direction of the reactions with respect to the member are approximately the same during transportation and storage as when the member is in its final position. Ensure that the storage, hoisting, and handling of the precast units prevents cracking or damage. Repairs must be approved by the Engineer at no additional cost to the Department. Rejection of Units. The Engineer will make a preliminary determination on whether spalled, cracked, honeycombed, or otherwise defective concrete must be repaired or be subject to rejection. If the unit will be repaired, submit a detailed non- conformance report and a detailed repair procedure to the Engineer for approval in writing before commencement of the repair work. Perform all repair work at no additional cost to the Department and in the presence of the Engineer. The Engineer will not accept any repair work not performed in his/her presence. The Engineer will reinspect the repaired unit.

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800-76SECTION 809 — PRECAST/PRESTRESSED STRUCTURE CONCRETE MASONRY

809.04METHOD OF MEASUREMENT

Precast, Prestressed Concrete Elements will be measured for the specific item or items of work as specified. All labor, equipment, tools and materials, including but not limited to backer rods, grouting between units, prestressing, patching of duct pockets , and all incidental items required to complete the work as specified and accepted by the Engineer will not be measured separately for payment but will be incidental to the other items of work covered in this Section.

809.05BASIS OF PAYMENT

General. The Department will pay for the completed and accepted quantities as follows. Pay Item Pay Unit Precast, Prestressed Concrete Elements SF or LF The price constitutes full and complete compensation for all labor, equipment, tools , and materials, including backer rods, grouting between units, prestressing, patching of duct pockets, and all incidentals necessary to finish the work, complete and accepted. Payment for Compensation for Out-of-State Inspection Services. If a Contractor selects a Subcontractor that is beyond a 50-mile radius of the Department’s base of operation, deemed to be the State Office Building (2 Capitol Hill, Providence, RI, 02903), the Contractor shall compensate the Department for the costs of travel and inspection services for the required days of inspection services. The Contractor shall pay for the out-of-State inspection services by the day (per diem) for each Department Engineer and/or Technician assigned to the plant for inspection of the P roject. The rates, which will be established based on the radius in miles from the base of operations, shall be as follows: Distance in Radial Miles Rates per Inspector/Day 51 to 100 miles $150.00 Greater than 100 miles $500.00 There shall be a maximum charge of one inspector for precast operations and two inspectors for prestress operations. The Contractor shall be credited 50 percent of the rates in the Table above when a plant is performing operations for two or more Department Contracts. The Contractor will not be charged for an initial inspection of a company or a single follow -up inspection for plant approval before initial production. The compensation payment for out -of-State inspection services will be paid as a progress payment deduction.