Performance comparison of steel and composite pipelines under fault displacement

Pipelines are commonly used to transport a large amount of hydrocarbon fuel and water that may cross active faults. Therefore, in this paper, the mechanical response of steel and composite buried pipeline under permanent strike–slip fault movement is studied using a 3D nonlinear finite element approach analysis. The behavior of the surrounding soil modeled by Mohr-Coulomb constitutive equation. Extensive fault movement leads to the large imposed displacements on the pipeline, which may then fail due to the excessive deformation. A parametric investigation was conducted and the effective factors such as the dimension of the pipe and composite lay-up have been studied. In this research, proper performance criteria were used to determine the critical fault displacements and according to the stress criteria, the critical fault displacement for steel and composite pipe was determined. It was concluded that the lay-up of the composite pipe has a significant effect on the response of the pipe subjected to the fault displacement. In addition, the comparison conducted between the composite pipe and steel pipe in the same condition shows that the composite pipe has better response and design safety factor.