Pipe Restraints: Design Fallacies

Abstract

Harnessing is a technique of resisting thrust in pipe bends where it is judged to be a more economic alternative than casting anchor blocks, or where the ground in which pipe is buried is weak or unstable and, thus, is incapable of economically providing passive pressure necessary for thrust blocks. Some erroneous technical papers have been in circulation which have influenced design in some circles to the economic detriment of the projects involved. This paper refutes formulas often used to calculate the tensile force in the first joint at bends in pressure pipelines where Jhrust is resisted by restrained or harnessed joints.