Case Studies of Thrust Restraint Analysis of Buried Pipelines Considering Effects of Temperature, Earthquake, and the Poisson’s Effect of Internal Pressure

This paper presents three case studies of thrust restraint analyses using a recently developed analytical solution that is modified from the current approach from the AWWA M9 manual, including the effect of temperature and earthquake loads, as well as the effect of Poisson’s effect of internal pressure-induced circumferential strains on longitudinal stresses. These three case studies represent typical scenarios for a small diameter Glass Fiber Reinforced Plastic (GFRP) pipe in a power plant, a large diameter Prestressed Concrete Cylinder Pipe (PCCP) in a water transmission main, and a medium diameter steel pipe in a transcontinental natural gas transmission pipeline, respectively, when subjected to moderate to high internal pressures, temperature, and earthquake loads. The resulting demands on the pipe segments adjacent to the pipe bends are compared to the demands obtained from using linear superposition method to combine the demands from the current AWWA M9 manual and temperature and earthquake loads. The case studies indicate that the linear superposition method results in unconservative estimates of the stresses in the pipeline.