SECTION 605 PRESTRESSED AND PRECAST CONCRETE PRODUCTS
605.01 DESCRIPTION. Construct precast prestressed concrete members.
Provide complete members, including all steel and other materials. Members include I-beams, box beams, barrier walls, deck units (box beams and slab), box culverts, and piling and other structural items. Fabricate according to the Department’s Precast and Prestressed Concrete Products Inspector’s Manual.
605.02 Materials and Equipment.
605.02.01 Concrete. Conform to Subsection 601.02 and 601.03.
605.02.02 Steel Reinforcement. Conform to Section 811.
605.02.03 Prestressing Strands. Conform to Section 811.
605.02.04 Non-Shrink Grout. Conform to Subsection 601.03.
605.02.05 Forms. Conform to Subsection 601.02. Only use metal forms for
prestressed sections, except that wooden bulkheads are acceptable. Ensure that all forms are accessible for vibrating, tamping, and consolidating the concrete.
605.02.06 Styrofoam. Use material the Engineer approves.
605.02.07 Cardboard. Use material the Engineer approves.
605.02.08 Batching Plant Equipment. Conform to Subsection 601.02.
605.02.09 Plant Certification. Ensure that all prestressed and precast concrete
products supplied to Department of Highways’ projects are manufactured in a Certified Plant.
A.Requirements. For a plant to become a Certified Plant, ensure that the producer has the following:
1.A production facility and other necessary equipment that conform to the Contract requirements.
2.A quality control program conforming to Division 100 of the Department’s Precast and Prestressed Concrete Products Inspectors Manual.
3.An acceptable record of production of quality products.
4.Concrete technicians responsible for design of the concrete mixture and for performing quality control and process control testing, as required in Subsection 605.02.09 and Division 300 of the Department’s Precast and Prestressed Concrete Products Inspectors Manual. Ensure that the concrete technicians are certified as ACI Level I and KCA Level II as awarded by the KCA. A Level I concrete technician is responsible for quality control tests such as air content, slump, and molding cylinders. A Level II concrete technician is responsible for supervising this testing. The Engineer may require retesting or re-certification as deemed necessary .
B.Application for Certification. Each year, ensure that the plant submits a written application for plant certification before January 1 to the Division of Materials. Ensure that the plant submits an application for re-certification when transferring 605-1 plant ownership. Ensure that the plant includes the following items with the application:
1.Company name, physical plant address, th e principle officers of the company, plant manager, production superintendent, and quality control supervisor.
2.The names and certification levels of the concrete technicians responsible for design of the concrete mixture and for performing the required quality control and process control testing. The Department will place any plant that has not previously manufactured products for the Department on a one-year probationary period before qualifying it as a Certified Plant.
C.Additional Prestressed Concrete Certification. Ensure that all prestressed concrete members supplied to the Departme nt are manufactured in a plant that is certified under the appropriate Prestresse d Concrete Institute quality control program and is designated as a PCI Certified Plant.
605.02.10 Concrete Production. During production of concrete products, ensure that
the producer conforms to all requirements of the Contract, and ensure that the concrete technicians perform all quality control and process control testing required by the Precast/Prestressed Concrete Manual and any applicable KM. The Inspector will perform the inspection duties established by the Department for the item being produced, including but not limited to the duties in the Department’s Precast and Prestressed Concrete Products Inspectors Manua l. If, at any time, the producer is not abiding by the certification requirements, the Inspector will reject or accept those products not manufactured according to the Contract requirements as specified in Subsection 105.04. When production problems occur which may affect the structural integrity, such as holes in webs and flanges, cracks, reinforcement displacement, submit proposed corrective procedures to the Engineer. The Department will evaluate the product and determine if it will be rejected or if corrective actions are reasonable. If a plant consistently produces products not conforming to the requirements as set forth in this agreement, the Department will revoke its certification, and the plant may not longer produce products for Department projects until the plant corrects all deficiencies and regains certification.
605.03 CONSTRUCTION. For prestressed concrete deck units, use Class D Modified
concrete of either Type I or Type III cement, except do not allow the cement factor to exceed 800 pounds per cubic yard. Ensure all non-composite box beam concrete contains an approved corrosion inhibitor from the List of Approved Materials. Construct prestressed members other than concrete deck units of Class D concrete that uses either Type I or Type III cement, except do not allow the cement content to exceed 800 pounds per cubic yard. When the ambient temperature is 71 F or higher, add a water reducing and retarding admixture to the concrete mixture for prestressed concrete products. The Engineer may direct or allow the use of water reducing and retarding or water-reducing admixture.
605.03.01 Mixing and Batching. Conform to Subsection 601.03.
605.03.02 Forming. Construct formwork according to Subsection 601.03.
When the ambient temperature is above 80 F, fog spray forms exposed to direct sunlight with water in order to cool the forms before placing the concrete mixture. When the ambient temperature is below 41 F, heat forms left unprotected from the weather with steam or other Engineer approved methods, unl ess the temperature of the concrete mixture to be placed is maintained at 60 F or greater. Fabricate voids of styrofoam or from cardboard that has been treated with a waterproofing agent. Glue and band all voids made by stacking more than one piece of material to prevent separation during concreting operations. The Engineer will regard any evidence of separation as cause for rejection. 605-2
605.03.03 Casting. Accurately place all steel, when required, as shown or directed.
Dimensions shown from the face of concrete to steel are clear distances. Spacings are from center to center of steel. Place and securely tie all steel reinforcement before placing concrete, unless the Engineer requires or allows otherwise. For concrete batching equipment and procedures, conform to Section 601. Do not begin concreting operations when the wind chill factor at the site is consistently 0 F or less. Place concrete continuously in each section, vibrating internally or externally or both to consolidate the concrete. Do not vibrate Self-Consolidating Concrete (SCC). Overfill the forms, screed off the surplus concrete, and finish the top surfaces to a uniform, even texture comparable to the finish produced by the forms. Give the top surfaces to be bonded to other concrete a rough finish. Initially, float finish the surfaces. Perform further finishing before the concrete takes its initial set, by scoring the tops of the members transversely at approximately 3-inch centers with a pointed tool. Remove any laitance present during the finishing operations. Vibrate in a manner that avoids displacement of any steel or enclosures and segregation of the concrete. Properly embed steel and enclosures in the concrete. The Department will allow casting of members at the job site or at any location away from the job site. The Engineer will inspect members at the site of the casting, but will make final acceptance according to Subsection 105.12. Determine the compressive strength of the concrete from cylinders cast from concrete placed in the members and cured in the same manner as the concrete represented by the cylinders. Cast and test cylinders according to KM 64-305 and ASTM C 39, respectively. Imprint the name or trademark of the fabri cator of I beams, box beams, or deck units in the concrete near the abutment end of the right fascia beam or deck unit, on the beginning end of each bridge. Cast the name or trademark into the concrete according to Subsection
601.03.19 for the plate used to imprint the construction date.
The Department will inspect, sample, and test precast units to determine their acceptability. The fabricator is responsible for providing quality control personnel as necessary to ensure the work performed complies with all requirements of the Contract. Ensure that fabricators of prestressed concre te members furnish, as part of their quality control equipment, a pachometer for determining the depth of concrete cover over steel reinforcement. Furnish a meter that is acceptable to the Engineer. Make the pachometer available for use by both the fabricator’s quality control personnel and by the Inspectors.
605.03.04 Tack Welding. The Department does not allow tack welding.
605.03.05 Special Requirements for Prestress Plants.
A.Hot Weather Production. In addition to the requirements of Subsection 605.03, ensure that the producer applies the following requirements to outdoor prestress operations:
1.When the ambient temperature is above 80 F sprinkle or fog spray coarse aggregates.
2.Discontinue concreting operations when ambient temperatures are between 90 and 100 F if the producer cannot effectively maintain form and concrete temperatures below 90 F.
3.Discontinue concreting operations when ambient temperatures are above 100 F.
B.Drawings. Have the producer submit drawings conforming to applicable requirements of Subsection 607.03 for prestressed girders. Include with the shop drawings a detailed drawing, including the total number of stirrups, for each different mark number and a diagram of the detensioning procedure. The Department will not require reproducible drawings. Obtain the Department’s completed drawing review prior to releasing fabrication. 605-3
C.Safety Measures. Ensure that the producer takes effective safety measures to prevent injuries to personnel due to the breakage of strands or failure of anchorage devices during the tensioning operations. Ensure that the producer provides adequate protection that allows the Inspector to perform his normal duties. The Inspector will report any safety precautions deemed inadequate to the Division of Materials. The Inspector will abide by the safety rules established by the producer, provided that they do not interfere with his normal duties.
D.Prestressing. Ensure that the producer performs prestressing by pretensioning and provides a skilled technician knowledgeable of the pretensioning system used. Ensure that the producer conforms to the following:
1.Uses approved jacking equipment to perform prestressing.
2.When using hydraulic jacks, equips them with calibrated pressure gages. Calibrates the combination of jack and gage to an accuracy of 2 percent, and furnishes a graph or table showing the calibration to the Engineer. If using other types of jacks, furnishes calibrated proving rings or other devices to accurately determine jacking forces.
3.Accurately holds prestressing elements in position to stress by jacks.
4.Applies an initial force to each strand in beams or girders such as to develop a stress of 189,000 psi or such other stress as specified in the Plans.
5.Maintains a record of the jacking force and elongations produced thereby.
6.If desired, cast several units for precast sections in one continuous line, but stress them one at a time.
7.Does not transfer prestressing forces to any member or release end anchors before the concrete has attained a minimum compressive strength of 4,000 psi, as determined by tests of standard cylinders cured identically as the member. The Department may require a higher strength.
8.Removes forms and detensions prestressed members immediately after discontinuing steam curing or heat curing while the concrete is still warm and moist, when using either of these methods for curing.
9.Cuts or releases the elements in an order that minimizes the lateral eccentricity of the prestressing.
10.The Engineer will reject beams or girders having honeycomb of such extent to affect their strength or resistance to deterioration.
11.Makes an allowance of 0.0005 times the length for shortening of beams and girders as a result of shrinkage and elastic change.
E.Curing. Cure according to Subsection 605.03.06 except the producer may discontinue curing after the concrete reaches the detensioning strength.
F.Removal From Forms. The producer may remove and store precast, prestressed members from the casting beds after the prestress force has been applied, provided the Engineer approves arrangements for curing and protecting. Ensure that the producer conforms to the following:
1.Fills all air voids in the inclined surfaces of all I beams with grout.
2.Ensures that strand hold-down devices that remain in place are either a minimum of 1/2 inch from the surface of the concrete or are galvanized.
3.Patches all cavities.
4.The producer may use other type devices when the Engineer approves them. Complete all finishing operations on prestressed bridge beams within 48 hours of detensioning, except masonry coat ing, curbs, and damage repair as the Engineer directs.
605.03.06 Curing. Cure members either by water curing according to Subsection
601.03.17 or by rapid curing with low pressure steam or radiant heat.
Perform low pressure steam curing or radiant heat curing under an enclosure capable of adequately containing the live steam or ra diant heat. Use enclosures that allow free 605-4 circulation of steam or heat about the sides, ends, and tops of members and are constructed to contain the live steam with a minimum moisture loss. The Department will allow the use of tarpaulins or similar flexible covers that remain in good repair. Secure the tarpaulins in a manner that prevents the loss of significant steam and moisture. Allow concrete to attain its initial set before applying the steam or heat. After placing the concrete, allow an initial set period of not less than 2 hours before applying the steam or heat. When using water reducing and retarding admixtures, increase the initial set period to 4 hours. The Department will allow determination of the time of initial set using ASTM C 403 and waive the time limits specified herein when the initial set has been reached as determined by the referenced test. Prevent surface drying during the period between placing the concrete and applying the steam or heat by covering the members after casting or by keeping the exposed surfaces wet with a fog spray or a double layer of wet burlap. During the waiting period, do not allow the temperature within the curing chamber to fall below 50 F. Use live steam or radiant heat to maintain the curing chamber at the proper minimum temperature. During the initial application of live steam or radiant heat, allow the ambient temperature within the curing enclosure to increase at an average rate not exceeding 40 F per hour until reaching the curing temperature within the enclosure. Do not allow the maximum curing temperature within the enclosure to exceed 160 F. Apply live steam on the concrete forms in a manner that does not cause localized high temperatures. Apply radiant heat using pipes circulating steam, hot oil, or hot water. Perform radiant heat curing under a suitable enclosure to contain the heat, and minimize moisture loss by covering all exposed concrete surfaces with a plastic sheeting. Provide a method of maintaining moisture satisfactory to the Engineer. Water cure precast, non-prestressed, non-post- tensioned items for 3 days or rapid cure them with steam or heat overnight. The Department will allow curing to cease when the acceptance strength is reached as shown by test cylinders.
605.03.07 Removal of Forms and Surface Finish. The Department will allow the
removal of side forms at any time when no distortion, slump, or misalignment of the concrete will result. Ensure that all surfaces are free from rough, open, or honeycombed areas, and appreciable depressions or projections . Finish or chamfer edges as directed. When removing the forms, avoid spalling or otherwise damaging the concrete. Finish members that will be exposed in the finished work according to Subsection 601.03.18. Finish dry cast products according to the Precast/Prestressed Concrete Manual. Repair vents opened to relieve air pressure in box beams during curing using non-shrink grout.
605.03.08 Dimensional Tolerances. Ensure that the producer furnishes members
within the tolerances of the following tables. The Engineer will condition final acceptance upon satisfactory placement of the units in the structure. 605-5 I-BEAMS, BOX BEAMS WITH CAST-IN-PLACE SLAB, AND PRECAST BARRIER UNITS Depth (flanges, web, and fillets) 1/4 inch Depth (overall) + 1/2 inch to – 1/4 inch Width (flanges and fillets) + 3/8 inch to – 1/4 inch Width (web) + 3/8 inch to – 1/4 inch Length of Beam 1/8 inch per 10 feet or 3/4 inch, whichever is greater Exposed Beam Ends (deviation from square or designated skew) Horizontal 1/4 inch; Vertical 1/8 inch per foot of beam height Side Inserts (spacing between centers of inserts and from the centers of inserts to the ends of the beams) 1/2 inch Bearing Plate (spacing between the centers of bearing plates) 1/8 inch per 10 feet or 1/2 inch, whichever is greater Bearing Plate (spacing from the centers of bearing plates to the ends of the beams) 1/4 inch Bearing Plate or Bearing Area (deviation from a level plane) 1/8 inch Stirrup Bars (projection above top of beam when design projection is more than 3 inches) 3/4 inch Stirrup Bars (projection above top of beam when design projection is 3 inches or less) 1/2 inch Stirrup Bars (long, spacing, anchorage zone) 1/2 inch Stirrup Bars (long, spacing) 1 inch End Stirrup Bars Not more than 2 inches from the end of the beam Horizontal Alignment (deviation from a straight line parallel to the centerline of beam) 1/8 inch per 10 feet Camber of precast barrier units 1/4 inch per 10 feet Camber differential between adjacent beams 1/8 inch per 10 feet of span to 1 inch max. Center of gravity of strand group 1/4 inch Strand positioning 1/4 inch Center of gravity of depressed stand group at the end of beam 1/2 inch Position of hold-down points for depressed stands-lon gitudinal 6 inches Position of handlin g devices-lon gitudinal 6 inches Position of material for debondin g of strands 1 inch 605-6 DECK UNITS (Box Beams and Slabs) Depth (top slab, box beam) 1/2 inch Depth (bottom slab, box beam) 1/2 inch Depth (overall) 1/4 inch Width (web, box beam ) 3/8 inch Width (overall ) 1/4 inch Length 1/8 inch per 10 feet or 3/4 inch, whichever is greate r Void position-longitudinal (flat slab) 1/2 inch from end of void to center tie hole; 1 inch adjacent to end block Void position-transverse and vertical (flat slab) 1/2 inch Square ends (deviation from square) 1/4 inch Skew ends (deviation from designated skew) Skew angle equal to or less than 30 Skew an gle greater than 30 1/2 inch Bearing plate or bearing area plane (deviation from level plane) (Bearing plate or bearing area plane must be an evenly distributed 80 percent of true plane, when tested with a strai ghtedge.) 1/8 inch Horizontal alignment (deviation from a line parallel to the centerline of member) 1/4 inch, up to 40 feet length; 3/8 inch, over 40 feet and up to 60 feet in length; 1/2 inch, over 60 feet in len gth Dowel tubes (spacing between the centers of tubes and from the centers of tubes to the ends and sides of the member ) 1/2 inch Tie rod tubes (spacing between the centers of tubes and from the centers of tubes to the ends of the member) 1/2 inch Tie rod tubes (spacing between the centers of tubes to the bottom of the beam) 1/2 inch Total width of deck Theoretical width + 1/2 inch per joint Camber differential between adjacent units 1/4 inch per 10 feet, 3/4 inch max. Camber differential between high and low members in the same s pan 1 inch max. Side inserts positionin g 1/2 inch Stirrup bar positionin g 1 inch Stirrup bar (lon g, spacin g, anchora ge zone) 1/2 inch Strand positionin g 1/4 inch Handlin g device positionin g 6 inches Center of gravity of stand group 1/4 inch Curbs placed separately on prestressed box beams (Applies to any portion 10 feet in length over the entire len gth of the beam) 1/4 inch per 10 fee t Position of material for debondin g of strands 1 inch 605-7
605.03.09 Transportation, Storage, Handling, and Erection. Transport precast
girders in an upright position, and keep the poi nts of support and direct ions of the reactions with respect to the girder approximately the same during transportation and storage as when the girder is in its final position. Prevent cracking or damage during storage, hoisting, and handling of precast units. Replace units damaged by improper storing or handling. Do not ship precast units to the Project prior to attaining the specified acceptance strength. During erection of members, keep the bridge seats and tops of bearing devices free of foreign materials. While shifting members, lift members completely away from bearings. Temporarily brace and tie each prestressed concrete I-beam, after erection, in a manner that will prevent sliding, tipping, or other movement that may result from high winds, creeping down grade, or other causes, until casti ng the diaphragms. Erect and brace at least 2 adjacent members in any one span before suspending operations for any one day. Begin erecting deck units at the location designated or approved by the Engineer and proceed, one member at a time, across the roadway. After placing and fastening the units by transverse tie assemblies, fill longitudinal keys between the units with non-shrink grout and seal as specified in the Plans. Cure the non-shrink grout keys with 2 layers of wet burlap, or other approved covering, placed on the slab. Keep the non-shrink grout continuously moist for 3 or more calendar days, except cure commercial mixtures according to the manufacturer’s instructions. Do not place equipment used to lift deck units into place on a portion of the bridge which has been erected without obtaining the Engineer’s approval.
605.04 MEASUREMENT. The Department will not measure the work required to
qualify the tack welders and tack welding procedures for payment and will consider it incidental to the pay item for prestressed or precast members, except the Department will test the specimens at no expense to the fabricator.
605.04.01 Precast I-Beams. The Department will measure the quantity in linear feet.
The Department will not measure bearing devices for payment and will consider them incidental to this item of work.
605.04.02 Precast Panels. The Department will measure the quantity according to
Subsection 613.04.
605.04.03 Precast Box Beams. The Department will measure the quantity in linear
feet. The Department will not measure bearing devices for payment and will consider them incidental to this item of work. PILING Width or diameter - 1/4 + 3/8 inch Head out of square 1/8 inch per 12 inches of width Length of pile 1 1/2 inch Horizontal alignment (deviation from a straight line parallel to the centerline of the pile) 1/8 inch per 10 feet Void position-longitudinal 2 inches Void position-transverse 1/2 inch Void position-vertical 1/2 inch Stirrup bars or spiral position 1 inch Tendon positioning 1/4 inch Center of gravity of strand group 1/4 inch Handling device positioning 6 inches 605-8
605.04.04 Precast Concrete Median Barrier. The Department will measure the
quantity according to Subsection 508.04.
605.04.05 Precast Piles. The Department will measure the quantity according to
Subsection 604.04.
605.04.06 Prestressed Piles. The Department will measure the quantity according to
Subsection 604.04.
605.04.07 Masonry Coating. The Department will measure the quantity according
to Subsection 601.04.
605.05 PAYMENT. The Department will make payment for the completed and accepted
quantities under the following: Code Pay Item Pay Unit 08631-08634, 08639 Precast PC I-Beam, Type Linear Foot 08635-08638 Precast PC I-Beam Modified, Size Linear Foot 08628 Precast PC Panels See Subsection 613.05 08651-08672 Precast PC Box Beam, Designation Linear Foot 01953, 01955, 01967, Concrete Median Barrier, Type Linear Foot 01988, 01989, 01992, 01999 08060-08066 Piles-Precast Concrete, Size See Subsection 604.05 08080, 08082, 08086, Piles-Prestressed Concrete, Size See Subsection 604.05 08096 02998 Masonry Coating See Subsection 601.05 The Department will consider payment as full compensation for all work required under this section. 605-9 SECTION 606 BRIDGE RESTORATION AND WATERPROOFING WITH CONCRETE OVERLAYS
606.01 DESCRIPTION. This work shall consist of bridge deck restoration and
waterproofing with latex concrete overlays.
606.02 Materials and Equipment.
606.02.01 Concrete. Conform to Subsection 601.02 and 601.03.
606.02.02 Latex Admixture. Conform to Subsection 841.
606.02.03 Epoxy for Epoxy-Sand Slurry. Conform to Section 826.
606.02.04 Sand for Epoxy-Sand Slurry. Conform to Subsection 804.
606.02.05 Mortar Sand. Conform to Subsection 804 (for Grout-Bond Coat).
606.02.06 Latex Grout. Conform to Section 601.02.
606.02.07 Joint Materials. Conform to Section 807.
A.Filler. Use preformed expansion joint filler, Type II (cork).
B.Sealers. Use rapid cure silicone with closed-cell polyethylene foam back-up rod compatible with silicone sealant.
606.02.08 Concrete Curing Material. Conform to Section 823.
606.02.09 Structural Steel. Conform to Subsection 812 (for expansion dams and
joint build up).
606.02.10 Equipment. Conform to Subsection 601.02 with the following exceptions
and additions:
A.Mechanical Scarifiers or Grinders. Furnish mechanical scarifiers or grinders designed specifically for scarifying bri dge decks that the Engineer approves. Ensure that the scarifier or grinder is capable of producing a surface matching the existing slab cross section and that each pass of the machine matches the previous pass in elevation.
B.Hammers. Provide Power driven Hammers lighter than nominal 45 lb. class.
C.Sawing Equipment. Sawing equipment shall be a concrete saw capable of sawing concrete to the specified depth.
D.Hydraulic Impact/Skid Steer Type Equipment with a maximum rated striking Energy of 360 ft-lbs are permitted only in areas of concrete removal more than 6 inches away from boundaries of surface areas to remain in service. The Contractor is to provide data information to the engineer on the equipment they wish to utilize to ensure compliance with this note.
E.Mixers. In addition to the requirements of Subsection 601.02, furnish continuous mixers having a latex admixture supply portion equipped with a cumulative-type meter that can be read to the nearest 0.1 gallon. Furnish continuous mixers having a water supply portion equipped with a flow meter or other suitable device for calibrating the water supply, and a cumulative type water meter that can be read to the nearest 0.1 gallon. Ensure that the latex and water meters are readily accessible, accurate to within one percent, and legible.
F.Hand Tools. In addition to the requirements of Subsection 601.02, furnish sufficient hand tools for placement of stiff, plastic concrete capable of working the 606-1
Source: Kentucky Standard Specifications for Road and Bridge Construction, 2019 Edition. Pages 330–338 of 718.