Interaction between material properties, inspection accuracy and defect acceptance levels in strain based pipeline design

Nowadays, pipelines are being built in regions where ground movements can cause post-yield longitudinal strains. Consequently, established material selection and weld integrity assessment procedures need to be reassessed. This is because the actual material properties, and not the specified ones, determine the plastic strain capacity, Also, the accuracy with which the material properties and defect parameters are established needs special care. The purpose of this paper is to review the variables affecting the plastic strain capacity and to discuss the associated material and inspection requirements. The information presented has been inferred from studies of the failure characteristics of large-scale Curved Wide Plate (CWP) tests