Creep Deflection of Thick-Walled Piping due to Combined Bending and Internal Pressure

Abstract

A closed-form solution is derived for the creep deflection in thick-walled piping subjected to combined internal pressure and bending moment. The solution is limited to the situation usually encountered in practice with sustained gravity loads and support forces in which the additional stresses due to bending are small compared to those due to internal pressure. For this case, it is shown that a simple correction factor may be applied to an elastic computation of pipe deflections to include the effect of creep. Predictions using this factor show satisfactory agreement with observations on a thick-walled piping system which had been in service for 20 years.