Date of Award

Winter 1992

Document Type


Degree Name

Doctor of Philosophy (PhD)


Civil/Environmental Engineering


Civil Engineering

Committee Director

Leon R. L. Wang

Committee Member

J. Mark Dorrepaal

Committee Member

Duc T. Nguyen

Committee Member

Zia Razzaq


This research is a study of the general seismic response behavior of buried pipeline systems during a soil liquefaction process. To aid the design of buried pipelines in a soil liquefaction environment, the purpose of this research is to provide the basic dynamic seismic response of different pipeline systems. Several important parameters such as pipe diameter, buried depth, additional mass and the size of the liquefiable soil zone have been introduced. The pipeline systems under study are cross-types, T-types and straight pipelines, with or without a manhole, buried in a soil liquefiable zone.

Time-varying soil spring constants are used for the analysis of the soil liquefaction process. The equation of motion includes nonlinear geometric and material damping terms. The pipe body is assumed to be elastic.

A computer program based on the finite element method has been developed. The mode superposition method is used to solve the equation of motion of the pipeline. The required eigenvalues and eigenvectors are calculated by subspace iterations. A few uncoupled modal equations of motion are solved by a step-by-step numerical integration method. This dissertation presents the background, formulation, verification of the developed program, numerical results, conclusions of seismic response of buried pipeline systems under a soil liquefaction environment and suggestions of future research to aid seismic design of pipeline systems.