Structural Design of Pipeline Casing Pipes

The ASCE Committee on Pipeline Crossings of Railroads and Highways conducted a field performance study on five experimental casing pipes under mainline railroads at various locations. Also, the measured deflections of several abandoned casings were obtained. A method of design for bored-in-place casing pipes under railroads and highways, based upon facts obtained in the experimental research has been developed and is presented. Earth loads are calculated by the Marston Theory of loads on ditch conduits. Rail traffic loads are estimated by the Newmark integration of the Boussine sq equation and highway traffic loads by the Holl integration. Using conservative systems of locomotive and truck wheel loadings, casing pipe thicknesses for a range of pipe sizes and depths of cover have been calculated. The results are consistent with the observed performance of the experimental casings. They are presented in both tabular and graphical form in the paper.