4145 Concrete Culvert Pipe

Section 4145. Concrete Culvert Pipe.

4145.01 GENERAL REQUIREMENTS.
These specifications cover reinforced and nonreinforced concrete pipe intended for construction of culverts, sanitary sewers, and storm sewers. This pipe shall be manufactured in accordance with the contract documents. Pipe furnished shall be produced by a plant for which method of manufacture and quality of product have been approved by the Engineer.

4145.02 CLASSIFICATION.
Concrete pipe will be furnished in classes according to their strengths. These will be designated as 1500D, 2000D, 3000D, and 3750D (75D, 100D, 150D and 175D) pipe. These classes indicate the D load (test load in pounds per linear foot of length per foot (Newtons per meter of length per millimeter) of inside diameter) to produce the ultimate load specified.

The class, design, date of manufacture, and trademark shall be plainly marked or stenciled on the inside of the pipe near the tongues not later than 24 hours after the pipe is made. If a manufacturer operates two or more plants, this marking shall include a separate distinctive designation for each plant. Any markings made using paint shall be renewed before original markings become unreadable. When strength of pipe is related to its orientation because of design or reinforcement, each piece shall be permanently marked, at least once inside and once outside on opposite walls, to indicate the top.

4145.03 MATERIALS.
Materials used for concrete culvert pipe shall comply with the applicable requirements of Division 41.

4145.04 DESIGN.
For circular pipe, details of the shell, design, and distribution of reinforcement as required, shall conform to requirements of AASHTO M 86/86 M for diameter less than 12 inches (300 mm), or AASHTO M 170/170 M for the modified design shown in the contract documents for diameters 12 inches (300 mm) or larger, except that elliptical reinforcement shall not be used in a circular pipe with a diameter less than 36 inches (915 mm). When circular pipe with gaskets is specified, AASHTO M 198 or AASHTO M 315 shall apply.

When reinforced concrete arch pipe is specified, AASHTO M 206/206 M shall apply.

When reinforced concrete elliptical pipe is specified, AASHTO M 207/207 M shall apply.

When pipe of an AASHTO design is furnished, the minimum thickness of any part of the joint shall be not less than 30% of the computed wall thickness, and the length of any part of the joint shall be not less than shown in the following table:

Computed Wall Thickness Minimum Length of Joint

3" (75 mm) or Less
3" to 6" (75.1 mm to 150 mm)
6" to 9" (150.1 mm to 225 mm) 87% of computed wall thickness
75% of computed wall thickness but not less than 2 3/4" (70 mm)
61% of computed wall thickness but not less than 4 1/2" (115 mm)

The computed wall thickness shall be not more than 1 inch per foot (25 mm per 300 mm) of pipe diameter or equivalent diameter, plus 1 inch (25 mm).

4145.05 STRENGTH.
Pipe shall have the strength specified for the class and design used, including both ultimate load and load to produce a 0.01 inch (0.3 mm) crack. Pipe of the modified design shown in the contract documents shall meet requirements of AASHTO M 170/170 M except the load to produce a 0.01 inch (0.3 mm) crack will not be measured for nonreinforced pipe. All strength tests will be conducted according to AASHTO T 33.

4145.06 MANUFACTURE.
The term "cast pipe" shall mean pipe manufactured by placing concrete of plastic consistency between forms and consolidating it by vibration.

Details of the manufacture of pipe shall conform to the following requirements:

A. General Requirements.
The storage of cement, measuring of materials, mixing concrete, and use of ready mixed concrete shall meet applicable requirements of Article 2301.13, B and D. Use of admixtures shall be subject to approval of the Engineer. Aggregate shall be so stored and handled as to avoid contamination and frequent variations of specified gravity, gradation, and moisture content. The Engineer may also approve procedures for concrete placement at low temperatures based on applicable requirements of Article 2403.11 and facilities to be used. When cages are to be made by resistance welding, the reinforcement used shall be housed in a weatherproof building and not in contact with the ground. Article 2404.03 shall apply to reinforcement.

B. Casting Base.
Forms for cast pipe shall rest on a clean, smooth, and level concrete base when the concrete is placed.

C. Construction of Reinforcement Cages.
Welded wire fabric reinforcement cages shall be formed by a machine designed for this purpose. The machine shall be constructed and operated to produce cages accurately formed to the required shape and dimensions. Reinforcement fabric that has been kinked from tight winding or other cause shall be straightened to the extent that a true shaped cage can be formed from it, or the reinforcement fabric shall be discarded. The length of all laps of circumferential reinforcement shall be not less than 40 diameters of the wire. No lap will be required for groove hoop wires in single line pipe.

Cages shall be held in the desired shape by welding the circumferential wires. Circumferential wires may be welded to transverse wires with resistance welds, or circumferential wires may be welded together within the laps by arc welds. If resistance welds are used there shall not be less than one weld on each circumferential wire, and these welds shall be distributed alternately between the two transverse wires in the lap except when normal spacing is so that two transverse wires will not fall within the lap. These welds shall not reduce strength of the wire below 70,000 psi (480 MPa).

Arc welds shall be long enough to hold the wires firmly together and to withstand handling and placing. All the welds which are broken before the outside form is placed around the cage shall be rewelded before being used. The position of the weld shall be near the center of the lap. The strength of the two wires welded together shall be not less than 70,000 psi (480 MPa), based on the cross sectional area of one wire in square inches (square millimeters). The number of arc welds shall be not less than 1 per foot (1 per 0.3 meter) of length of cage, plus one weld.

Pipe 54 inches (1350 mm) in diameter and larger of 3000D (150D) class manufactured according to the modified design shall have inner and outer cages tied together by clips or other approved methods. Clips, if used, shall be placed in not less than one circumferential row per foot (300 mm) of length of cage plus one. The spacing in each row shall not be more than 8 inches (200 mm) along the outer cage within 45 degrees of the top and bottom of the pipe. Clips shall not be smaller than No. 6 (4.877 mm diameter) wire.

D. Forms.
Forms shall be smooth and true to shape and dimensions and maintained in good condition.

E. Placing Concrete.
Concrete not consolidated during placement by a machine designed for that purpose shall be consolidated by vibration. External vibrators shall be applied to the forms to ensure against causing the form to be dented and deformed.

F. Lift Holes.
When requested by the Contractor, pipe may be furnished with not more than two lift holes. Lift holes shall not be larger than 2 1/2 inches (65 mm) in diameter and shall be cast or formed in a manner so that there are no breaks of the circumferential reinforcing of single cage reinforced pipe or of the inner cage of double cage reinforced pipe. When practicable, circumferential wires will be bent slightly to provide for the lift holes.

Cutting of circumferential wire in lift hole locations will be permitted if the pipe satisfies the 0.01 inch crack test requirements of AASHTO M 170/170 M for the specified class of pipe.

G. Curing.
Pipe shall be cured by one of the wet methods specified in AASHTO M 170/170 M or by some other method approved by the Engineer which will give uniform and consistent curing and will produce pipe which will meet the strength requirements.

H. Yarding.
Lines of pipe in storage yards shall be placed at least 2 feet (0.6 m) apart with both ends of each pipe readily accessible to facilitate inspection.

I. Tongue and Groove.
The tongue and groove shall be compatible so that when the pipe are laid, it will be possible for the contractors to conform to Article 2416.04, E.

J. Pipe Connectors.
When required, pipe connectors shall be of the design shown in the contract documents or an approved alternate.

K. Special Shapes.
The contract documents may require pieces of special design. If not specified, the class specified will indicate reinforcement requirements.

4145.07 REJECTION.
In addition to causes for rejection as listed in AASHTO M 170/170 M or AASHTO M 86/86 M, failure to meet the requirements specified above shall be sufficient cause for withdrawing approval of a manufacturer. Withdrawal or approval of a manufacturer may apply to certain specific sizes or to all sizes of pipe.

Computed Wall Thickness	Minimum Length of Joint
3" (75 mm) or Less 3" to 6" (75.1 mm to 150 mm) 6" to 9" (150.1 mm to 225 mm)	87% of computed wall thickness 75% of computed wall thickness but not less than 2 3/4" (70 mm) 61% of computed wall thickness but not less than 4 1/2" (115 mm)