3236Reinforced Concrete Pipe

3236.1SCOPE

Provide reinforced concrete pipe of circular, arch, elliptical, or special shape and design, with appropriate appurtenances to construct Culverts, sewers, or underpasses.

3236.2REQUIREMENTS

Provide reinforced concrete pipe meeting the following requirements and as modified in this section: Table 3236.2-1 Reinforced Concrete Pipe Pipe Type AASHTO Reference Circular AASHTO M 170 Standard Specification for Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe Pipe-Arch AASHTO M 206 Standard Specification for Reinforced Concrete Arch Culvert, Storm Drain, and Sewer Pipe Elliptical AASHTO M 207 Standard Specification for Reinforced Concrete Elliptical Culvert, Storm Drain, and Sewer Pipe

Provide concrete aprons manufactured as shown on the Plans. Attach aprons compatible with pipe. Provide concrete cattle pass units manufactured as shown on the P lans. The Department will not require external load bearing tests on cattle passes and aprons. A Materials A.1 Aggregate Quality ........................................................................... 3126, 3131 and 3137 The Department will allow admixtures in accordance with 2462, “Precast Concrete.”

B Pipe Design Provide pipe designed as shown on the Plans or meeting the AASHTO requirements referenced in Table 3236.2-1, if approved as an alternate by the Engineer for the different classes of pipe meeting the following design requirements:

Provide pipe with reinforcement placed in accordance with applicable AASHTO specifications referenced in Table 3236.2-1, except as otherwise shown on the Plans or as approved by the Engineer. Do not use circular pipe with elliptical reinforcement. Lap wires in the circumferential steel welded wire reinforcement a minimum of forty wire diameters and include a transverse wire from each side of the lap. Fully welded lap splices will not be allowed without specific approval of the Materials Engineer. If the Plans show pipes with rubber gasket seals, ensure the joint surfaces adjacent to the gasket are smooth and free of imperfections to allow the rubber gasket seal to meet the specified performance requirement. C Manufacture Provide products manufactured in a precast concrete manufacturing plant pre -approved by the Materials Engineer, listed on the APL and meeting the requirements of 3240, “Precast Concrete Manufacturing.” Provide certified products as required by the Contract from a manufacturer with total production set-up on a pre-approved basis for that product type (pipe, end sections, or manholes) . The Materials Engineer will limit acceptance of products to each precast concrete manufacturer, to each of the plants and to each product type as pre-approved by the Materials Engineer. The Materials Engineer will limit pre-approval to the identified sizes of circular pipe, arch pipe, elliptical pipe, and product type . Sizes and classes without designs shown in the Standard Plates or with a span greater than or equal to 120 inches will not be pre-approved. Notify the Materials Engineer at least 5 Business Days before the manufacturer begins producing pipe requiring shear steel or Special Designs not listed on the APL. Pin all shear steel. Positive slump concrete shall be air-entrained. Zero-slump concrete shall be according to AASHTO M170. Provide concrete units cured by the steam or water curing methods, unless using methods otherwise approved by the Materials Engineer. In all cases, use curing chambers with an atmospheric temperature no greater than 160°F. Protect concrete units from freezing or drying after casting until the completion of curing. D Permissible Variations Provide pipe meeting the tolerance requirements of applicable AASHTO specifications referenced in Table 3236.2-1. Manufacturers of reinforced concrete pipe may produce an alternate “ offset joint” on the spigot end of the pipe. This type of offset joint is to be used with the profile or pre -lubricated pipe seal systems. See Standard Plate 3006.

3236.3SAMPLING AND TESTING

The Materials Engineer will approve each precast concrete manufacturer and its individual plants to provide precast concrete products under the pre-approval program. The Materials Engineer will not authorize precast concrete production if the manufacturer fails to abide by the terms, conditions, and requirements contained in this program. If the Materials Engineer finds manufacturer non-compliance with the pre-approval program or evidence of non-conformance of certified products, the Materials Engineer, in conjunction with the Engineer, may perform any of the following:

A Plant QC Ensure the manufacturer establishes and implements a QC program, including the following elements for each pre-approved plant: A.1 Internal QC Program Ensure the manufacturer includes the following in the internal QC program:

acceptability if Materials were previously inspected and tested, or received from a certified source

and type of manufacture, on the first run of the year and as directed by the Materials Engineer, provide core specimens at least 4 inches in diameter for the absorption test and steel verification

A.2 On-Site Quality Control Technicians Ensure the manufacturer employs and has on-site during production QC technicians trained and certified meeting the requirements of Department Level I, “Concrete Field Tester” or ACI Grade I, “Quality Control Technician” to perform the following:

products

pre-approved products

10 percent of the respective surface, inside or outside A.4 System of Record Keeping Ensure the manufacturer maintains the following records:

certification, or other evidence of inspection and satisfactory testing

the records section of the ACPA Manual

B Quality Assurance The Materials Engineer will visit each plant to perform tasks in accordance with thisS pecification and including the following: Random sampling and testing of the Materials used in the manufacture of pre-approved products Random sampling and testing of the pre-approved pipe produced Observing the manufacturing process Reviewing the manufacturer’s quality control tests, inspection, records , and stockpiling practices Reviewing the pre-approved product inventory The Engineer will perform a final inspection upon delivery. C Testing Rates C.1 Concrete Ensure the manufacturer tests the air content of concrete in each mix once a day for each positive slump mix. Ensure the manufacturer tests the concrete strength of each mix according to the requirements of 3240.2F.3.a, “Concrete.” C.2 Load Bearing Test Ensure the manufacturer conducts three-edge bearing tests meeting the requirements of AASHTO M 170 Standard Specification for Reinforced Concrete Culvert, Storm Drain, and Sewer Pipe, on each size and class of pipe, and in accordance with the following schedule:

Table 3236.3-1 Minimum Three Edge Bearing Testing Rates Size Range, inch Class Range Test Rates 12 – 15 ≤ 5 1 per 1000 pieces 18 – 36 ≤ 4 1 per 800 pieces 18 – 36 5 1 per 400 pieces 42 – 60 ≤ 3 1 per 400 pieces 42 – 60 4 & 5 1 per 200 pieces 66 – 96 ≤ 5 1 per 200 pieces NOTE: Testing rates for sizes not shown are as required by the Project Specifications. Begin a new schedule of testing after changing the mix design, after shutting down the system for major repairs and renovations, when beginning a new production run, and when beginning a new season. Thes e rates are for testing to the 0.01 in D- load. Testing to failure is required on each combination of pipe size, wall thickness, and class manufactured once per production year. For arch pipe smaller than 88-inches nominal span, one piece per year of each size and class manufactured is required to be tested to 0.01 in D-load. Besides, testing to failure is required for arch pipe smaller than 88-inches nominal span on each combination of pipe size and class manufactured once per production year.

Notify the Materials Engineer 2 full Business Days before testing. The Materials Engineer may select pipes for testing and may direct the manufacturer to perform additional testing at no additional cost to the Department. Do not ship pipe that have not developed the specified D-load. Only pipe of equal or older age than a tested pipe section of the same size and class that has passed the three -edge bearing test may be shipped. Maintain documentation of all load tests performed. D Pipe Marking Provide pipe marked by the manufacturer in accordance with the following: Meeting the marking requirements of AASHTO M 170 Stamped with the word, “Certified” Stamped with the manufacturing plant identification For units at least 24 inches in diameter, stamped on the inside For units smaller than 24 inches in diameter, stamped on the outside Before stockpiling, mark products manufactured for Projects with special requirements not meeting the standards of the pre-approved program with an identifying Project number or the buyer’s name. The Engineer may accept pre-approved shipments if the Contractor provides pipe marked with the following by the manufacturer:

Provide the Engineer with a certified bill of Materials or invoice, signed by a designated, responsible company representative with each shipment that identifies the following information:

“The Materials itemized in this shipment are certified to be in compliance with the applicable Minnesota Department of Transportation Specifications and the Project Plans, including any BABA provisions.”

Authorized Signature and Date Ensure the manufacturer does not ship pre-approved products until after the completion of QC tests and inspections, and as approved by the Materials Engineer. E Stockpiling Ensure the manufacturer stockpiles products meeting the above requirements to allow the Materials Engineer to inspect the products for QA, and that the manufacturer stockpiles special, non-pre-approved product in areas separate from pre-approved stock.