ASTM C507-18 pdf download.Standard Specification for Reinforced Concrete Elliptical Culvert, Storm Drain, and Sewer Pipe.
8. Reinforcement
8.1 Circumferential Reinforcement—A line of circumferen- tial reinforcement for any given total area may be composed of two layers for pipe with wall thicknesses of less than 7 in. or three layers for pipe with wall thicknesses of 7 in. or greater. The layers shall not be separated by more than the thickness of one longitudinal plus 1 ⁄ 4 in. The multiple layers shall be fastened together to form a single cage. All other specification requirements such as laps, welds, and tolerances of placement in the wall of the pipe, etc., shall apply to this method of fabricating a line of reinforcement.
8.1.1 Where one line of reinforcement is used, it shall be placed so that the cover ofthe concrete over the circumferential reinforcement at the vertical and horizontal diameters of the pipe is 1 in. from the inside and outside surfaces of the pipe, except for wall thicknesses less than 2 1 ⁄ 2 in., the protective cover of the concrete over the circumferential reinforcement in the wall of the pipe shall be 3 ⁄ 4 in.
8.1.2 Where two lines of reinforcement of elliptical shape corresponding to the contour of the pipe are used, each line shall be so placed that the covering of concrete over the reinforcement is 1 in. 8.1.3 The location of the reinforcement shall be subject to the permissible variations in dimensions given in 11.5. Re- quirements for placement and protective covering of the concrete from the inner or outer surface of the pipe do not apply to that portion of a cage which is flared so as to extend into the bell or reduced in diameter so as to extend into the spigot.
8.1.3.1 Where the wall reinforcement does not extend into the joint, the maximum longitudinal distance to the last circumferential from the inside shoulder of the bell or the shoulder of the spigot shall be 3 in. except that if this distance exceed one-half the wall thickness, the pipe wall shall contain at least a total reinforcement area of the minimum specified area per linear foot times the laying length of the pipe section. The minimum cover on the last circumferential near the spigot shoulder shall be 1 ⁄ 2 in.
8.1.3.2 Where the reinforcement is in the bell or spigot the minimum end cover on the last circumferential shall be 1 ⁄ 2 in. in the bell or 1 ⁄ 4 in. in the spigot.
8.1.4 The spacing center to center of circumferential rein- forcement in a cage shall not exceed 4 in. for pipe up to and including pipe having a 4-in. wall thickness nor exceed the wall thickness for larger pipe, and shall in no case exceed 6 in.
8.1.5 The continuity of the circumferential reinforcing steel shall not be destroyed during the manufacture of the pipe, except that when agreed upon by the owner, lift eyes or holes may be provided in each pipe for the purpose of handling.
8.1.6 If splices are not welded, the reinforcement shall be lapped not less than 20 diameters for deformed bars and deformed cold-worked wire, and 40 diameters for plain bars and cold-drawn wire. In addition, where lapped cages of welded-wire fabric are used without welding, the lap shall contain a longitudinal wire.
8.1.6.1 When splices are welded and are not lapped to the minimum requirements above, there shall be a minimum lap of 2 in. and a weld such that pull tests ofrepresentative specimens shall develop at least 50 % of the minimum specified tensile strength of the steel. For butt-welded splices in bars or wire, permitted only in helically wound cages, pull tests of repre- sentative specimens shall develop at least 75 % of the minimum specified tensile strength of the steel. Pull tests shall conform to Test Methods C497.ASTM C507 pdf download.