Section 578 — Precast Concrete Elements
Description
578.01This work consists of providing and installing precast concrete elements.
Material
578.02Conform to the following Subsections: Anchorage devices 722.01 Non-shrink grout 701.04(b)(1)
Construction Requirements
578.03Qualifications. Provide a precast concrete manufacturing plant, precast concrete QCM , and grouting personnel with experience in precast concrete. A t least 30 days before starting precast concrete work , submit the following for approval:
(a)Precast concrete QCM . Appropriate certifications ;
(b)Plant certification. NPCA certification or equivalent PCI certification. Use the same precast plant for the fabrication of all the precast elements ; and
(c)Grouting personnel. A résumé for each individual that will be responsible for grouting if grouting operations will be necessary for the fabrication or installation of the precast elements. Describe installation experience on at least two projects of similar complexity within the past 3 years.
578.04Submittals. At least 30 days before starting precast concrete work, submit the following according to Subsecti on 104.06:
(a)Precast bridge elements. Prepare fabrication and installation drawings and an installation plan.
(1)Fabrication. Show details necessary for fabrication. Include the following:
(a)Details and location of lifting holes, inserts, hardware, devices, and a ny additional reinforcing required for lifting ;
(b)Size of precast elements with consideration for shipping restrictions, equipment availability, and site constraints;
(c)Method of curing, handling, storing, and transporting the elements;
(d)Leveling inserts in the deck and leveling procedure;
(e)Details of vertical elevation adjusting hardware;
(f)Minimum compressive strength to be attained before handling precast concrete deck and deck overhang elements;
(g)Details of structural steel, shear connectors, bearing assemblies, and elastomeric bearing pads; and
(h)Concrete volume, reinforcing steel weight, and total section weight for each element.
(2)Installation. Describe details necessary for installation. Include the following:
(a)A work area plan depicting utilities overhead and below the work area, drainage inlet structures, protective measures, temporary staging areas, crane locations, and other features of the site necessary for successful installation;
(b)Lifting procedures and supporting calculations, including details of equipment and devices (including slings, hooks, and jacks) used for lifting and assembling the superstructure, substructure, and approach slabs. Include the make, model, lift capacity, and operating radii;
(c)Computations showing the magnitude of stress in the prefabricated components during erection is within allowable limits, and that the erection equipment has adequate capacity for the work to be performed;
(d)Detailed sequence of construction activities, and a CPM schedule according to Section 155 for installation operations. Include setting and cure time for grout, concrete closure pours, splice couplers, and fill of pile pockets;
(e)Methods of providing temporary support of the elements. Include methods of adjusting, bracing, and securing the element after placement;
(f)Procedures for controlling tolerance limits;
(g)Methods of forming closure pours and fill concrete, and sealing lifting holes; and
(h)Methods for curing grout, closure pours, and lifting hole concre te.
(b)Other precast elements.
(1)Fabrication. Submit drawings including tolerances.
(2)Installation. Submit an installation plan. Describe details necessary for installation. Include the following:
(a)A work area plan depicting utilities overhead and below the work a rea, drainage inlet structures, protective measures, temporary staging areas, crane locations, temporary support elements, and other features of the site necessary for successful assembly; and
(b)Details of equipment and devices (including slings, hooks, and jacks) used for lifting and installation. Include the make, model, lift capacity, and operating radii.
578.05Tolerances. Fabricate precast bridge elements conforming to the tolerances shown in Tables 578-1, 578-2, and 578-3. Fabricate other precast elements conforming to the tolerances in the approved drawings . Provide measurements and documentation to support that the precast elements were fabricated in conformance with the requirements. 666 Before shipping precast elements from the fabrication plant, verify that the precast elements will fit -up and align properly by assembling the elements or using other approved methods. Dry fit connections in the fabrication yard before installation of the elements at the project site. Table 578-1
Precast Bent Cap Fabrication Tolerances
Property Tolerance , inch (±) Length ¾ Width (overall) ¼ Depth (overall) ¼ Variation from specified plan end squareness or skew ¼ per 1 ft width ½ maximum Variation from specified elevation end squareness or skew ¼ per 1 ft width ½ maximum Location of grouted splice coupler measured from a common reference point ½ maximum Local smoothness of any surface ¼ per 10 ft Erection elevation tolerance ¼ Table 578-2 Precast Abutment and Wall Elements Fabrication Tolerances Property Tolerance, inch (±) Length ¼ Width (overall) ¼ Depth (overall) ¼ Variation from specified plan end squareness or skew ⅛ per 1 ft width ½ maximum Variation from specified elevation end squareness or skew ¼ per 1 ft width ½ maximum Location of grouted splice coupler measured from a common reference point ¼ Local smoothness of any surface ¼ per 10 ft Location of blockouts for piles or voids 1 Table 578-3 Precast Approach Slab Fabrication Tolerances Property Tolerance, inch (±) Length ¼ Width (overall) ¼ Depth (overall) ¼ Variation from specified plan end squareness or skew ½ Location of leveling bolts 1 Sweep over member length ⅜ Location of projecting reinforcing measured from a common reference point ½ Local smoothness of any surface ⅛ per 10 ft Erection elevation tolerance (surface approach slab only) ⅛ Location of blockouts ½
578.06Concrete and Reinforcing Steel. Construct concrete for precast bridge elements according to Section 552. Construct concrete for other precast elements according to Section 601. Construct reinforcing steel according to Section 554. Rough cast the top surface of members against which concrete will be cast. Rake the top surface of members receiving a concrete overlay to a depth of ⅜ inch. Do not expose the concrete to temperatures below 40 °F for at least 7 days after casting.
578.07Quality Control.
(a)Precast bridge elements.
(1)Permanently mark each element with date of fabrication, supplier identification, and module identification. Stamp markings in f resh concrete;
(2)Prevent cracking or damage of precast components during handling and storage;
(3)Replace or repair defective or broken precast concrete deck and concrete deck overhang elements as approved. Requests to repair defective or broken elements are subject to the following:
(a)Obtain approval before performing concrete repairs;
(b)Repair concrete to reestablish the precast elements structural integrity, durability, and aesthetics;
(c)Describe the cause of damage and the corrective action taken to eliminate futu re damage; and
(d)Update the CPM schedule showing the effects of repair work on project completion.
(4)Reject elements if they do not conform to the contract and for the following:
(a)Elements fabricated before the date that drawings are approved; 668 (b) Full-depth cracking of concrete, and concrete breakage that is not repairable;
(c)Cracks that extend to the nearest reinforcement plane, or fine surface cracks that do not extend to the nearest reinforcement plane but are numerous or extensive;
(d)Camber that does not meet the r equirements of the plans or approved drawings;
(e)Honeycombed texture; and
(f)Damage during fabrication, transportation, erection, or construction.
(5)Document and submit the following:
(a)Element identification;
(b)Date and time of fabrication concrete pour;
(c)Concrete cylinder test results;
(d)Concrete mix design and the batch print out;
(e)Form -stripping date;
(f)Location and number of blockouts and lifting inserts;
(g)Temperature, moisture, and duration of curing period; and
(h)Approved repair procedures.
(b)Other precast elements.
(1)Document and submit the following:
(a)Date and time of fabrication concrete pour;
(b)Concrete cylinder test results;
(c)Concrete mix design and the batch print out; and
(d)Temperature, moisture, and duration of curing period.
(2)Inspect elements for damage and cracking on site before installation. Reject elements if they do not conform to the contract and for the following:
(a)Full-depth cracking of concrete;
(b)Concrete breakage that is not repairable; and
(c)Cracks that extend to the nearest reinforcement plane, or fine s urface cracks that do not extend to the nearest reinforcement plane but are numerous or extensive.
578.08Transporting, Handling, and Storing. Before transporting precast elements, provide written certification from the precast concrete manufacturing plant QCM that the precast elements were fabricated and inspected to ensure compliance with the contract requirements. Move elements after the concr ete attain s a minimum compressive strength of 4500 pounds per square inch for precast bridge elements or a minimum of 80 percent of the required design compressive strength for other precast elements or as shown in the plans.
(a)Transporting. Transport precas t elements horizontally with beams on the bottom side for support. Support the precast elements at approximately the same points they will be supported when installed. Use shock- absorbing material at bearing points during transportation. Locate the tie -dow n straps at the lines of blocking only.
(b)Handling and storing. Store the precast elements in a horizontal and upright position, supported at their designated bearing points. Follow Chapter 5 of the PCI Design Handbook for handling and erection bracing requi rements. Lift the precast elements so that the angle between the top surface of the precast element and the lifting line is not less than 60 degrees when measured from the top surface of the precast elements to the lifting line. If two cranes are used, mai ntain vertical lifting lines. Lift the precast elements at the designated points. Account for stresses in precast elements during handling operations. Choose the locations of the lifting points so that the anticipated flexural tensile stress induced in the top of the structural concrete for the assumed support locations is not greater than the allowable stress. Select smooth and well compacted storage areas to prevent damage due to differential settlement. Support precast elements during storage to prevent cracking or creep- induced deformation (sagging). Check precast elements at least once per month to ensure that creep -induced deformation does not occur.
(c)Lifting devices. Do not cause damage, cracking, or torsional forces when using lifting devices . Place t he lifting devices in locations that are not visible once the precast element is placed, or within recessed pockets that can be patched after installation.
(d)Safety. Ensure the safety and stability of precast elements during all stages of handling, transport ation, and construction.
(e)Damage and cracking. Prevent cracking or damage of precast elements during storing, transporting, and erecting. Replace or repair damaged precast elements as approved.
578.09Acceptance. Anchor devices and material for grout will be evaluated under Subsections 106.02 and 106.03. Construction of precast elements will be evaluated under Subsections 106.02 and 106.04. Concrete for precast bridge elements will be evaluated under Section 552. Concrete for other precast elements will be evaluated under Section 601. Reinforcing steel will be evaluated under Section 554. 670 Measurement
578.10Measure the Section 578 pay items listed in the bid schedule according to Subsection 109.02 .
Payment
578.11The accepted quantities will be paid at the contract price per unit of measurement for the Section 578 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05. 671 DIVISION 600