The failure of buried pipelines was observed adjacent to active faults due to the movements of fault during earthquakes.The main failure modes include strength failure

local bucking

and integral destabilization.An accurate and efficient analysis model for a buried pipeline subjected to fault movements is of significance for seismic design of buried pipelines and safety evaluation after an earthquake.Lots of theoretical and numerical methods were developed to obtain the response of buried pipelines under fault movements.Especially

finite element method is employed to simulate pipe and soil interaction under fault movements.The assumption that only axial displacement shall take place for the part of the pipe with small deformation between pipeline and soil is proposed and proven by FE analysis in the paper.A nonlinear axial spring located on each end of the pipe is utilized to simulate the response of a buried pipeline far away from fault. Then

an updated pipe-soil equivalent model is used to decrease the analysis length of the part of the pipe with large deformation between pipeline and soil.The soil resistance per unit length of pipe is calculated with the recommendation method from the standard of American Lifelines Alliance.The effects of soil types

interaction between pipe and soil

and material nonlinearity of pipe steel are considered in the model.Kennedy method is introduced to obtain the calculating length of a pipeline.The results of the equivalent model proposed in the paper are compared with some models of a buried pipeline subjected to strike slip faults.