Finite Element Analysis of Buried Continuous Pipeline Subjected to Large Ground Motion

Abstract

Pipeline generally extends over long distances traversing through wide variety of different soils, geological conditions and regions with different seismicity and ground motions. Vulnerability of the pipeline due to seismic hazards can be divided in to three categories i.e. hazard due to ground vibration, hazard due to faulting and hazard due to permanent ground deformation (PGD). Though there are no severe damage were observed due ground vibration in the modern buried pipeline though it may trigger to secondary effect of landsliding and ground motion due to liquefaction. Main stream researches in past especially analytical models are limited to strike slip fault motions with tension in pipe case only. As the large geometric changes incorporating in analytical study is a tricky task; however pipeline subjected to the large ground motion itself is a phenomenon of large geometric changes. Especially when pipeline subjected to compression, where in addition to material deformation it also undergoes general as well as local buckling with bending, contradictorily past work mostly assumed that pipeline is under tension. With day by day increasing capacity of computation and advancement in numerical modelling, one can find more facts for pipeline subjected to large motions including cases of pipe under compression as well. In this paper, past work is reviewed for pipeline subjected to large ground motion. A three dimensional FE based numerical model is suggested to carry out pipeline performance of buried pipeline subjected to large motion. A proposed model includes material nonlinearity, as well as considers the large geometric deformation. For this purpose, three dimensional FE program is developed using MATLAB. Displacement controlled Arc-length technique is implemented to solve the nonlinear behavior. To reduce the computation time of analysis here parallelization tool kit of MATLAB is utilized. Keywords: Buried continuous pipeline; Large ground motion; Nonlinear-large deformation FEM; Displacement controlled Arc-length technique.