Ductile iron pipeline response to earthquake-induced ground rupture

Abstract

This article provides a comprehensive evaluation of ductile iron (DI) pipeline response to earthquake-induced ground deformation through the results of a large-scale testing program and a fault rupture test on a 150-mm DI pipeline with restrained axial slip joints. The test is used to validate a two-dimensional finite element (FE) model that accounts for soil–pipeline interaction with axial slip, pullout resistance, and rotation of pipe joints. The maximum strike-slip fault offset sustained by push-on, restrained, and restrained axial slip joints is presented as a function of the pipeline/fault crossing angle. DI pipeline performance is controlled by one of the following limit states; tensile, compressive, rotational joint capacity, or local buckling in the pipe barrel. A systematic FE assessment shows that pipelines with restrained axial slip joints accommodate 2–9 and 2–10 times as much fault offset as pipelines with push-on and restrained joints, respectively, for most intersection angles. The results of this work can be used for simplified design and to quantify the relative earthquake performance of different DI pipelines.