An overview of strain-based seismic design of high-pressure gas pipelines

摘要

An overview on the strain-based seismic design of a high-pressure gas pipeline to withstand both temporary and permanent ground deformation is presented in this paper. The ground deformations induced by seismic waves, liquefaction-induced lateral spreading, and surface faults are presented. The conventional and advanced methods to predict the strain capacity of a pipe subjected to axial compression or bending are discussed. The strain capacity of a standard linepipe with a Luders' elongation-type stress-strain curve and a high-strain linepipe with a round-house-type stress-strain curve are compared. The strain capacity of the round-house-type linepipe is expressed in terms of the stress ratio, σ_(2.0)/σ_(1.0), where σ_(1.0) and σ_(2.0) are the stresses in which the total strains are 1.0% and 2.0%, respectively. The stress ratio is the key parameter to predict the strain capacity of round-house-type linepipes. The strain capacity can be improved with increasing the stress ratio without increasing the wall thickness, which is the most advanced beneficial method for the reduction of the pipeline construction costs.