Shell Model FEM Analysis of Buried Pipelines under Seismic Loading

Abstract

This paper presents the development of an FEM formulation based on shell Models for the analysis of buried pipelines subjected to sinusoidal seismic wave, differential settlement and dislocation of ground. Realistic circumferential distribution of earth pressure and distortion of the cross section of the pipe, which can not be considered in the conventional method based on the beam model, were taken into consideration. Some comparison of numerical results obtained from the shell model-I, shell model-II and the beam model is carried out. It is found that very different axial stresses were given by each of the three models in the case of transverse ground deformation, and it is apparent that beam model and shell model-I are not suitable in such cases. Distortion of the cross section of pipes does occur in the case of stiff ground or thin pipes, which may make the circumferential stress become more significant than the axial stress. An empirical formula is presented to evaluate the ratio of axial stress obtained from these shell models.