Section 4144. Structural Plates for Pipe, Pipe Arches, and Arches
Structural units of corrugated metal of the specified thickness.
B. Ensure the diameter of the bolt holes in longitudinal seams, except those at plate corners, does not exceed the diameter of the bolt by more than 1/8 inch (2 mm). If elongated structural plate pipe is specified or called for in the contract documents, form the plates so the finished pipe is elliptical in shape with the vertical diameter approximately 5% greater than the nominal diameter of the pipe.
Use bolts that meet the requirements of ASTM A 449 or ASTM A 325, or are an approved equal. Use galvanized bolts and nuts.