Finite element model for cyclic loading of concrete filled steel tube pile

A non-linear finite element analysis is presented to predict the lateral response of a concrete-filled steel tube (CFT) pile subjected to cyclic loading. The computer program CFTPILE was developed as a part of this study. The pile is modeled as a beam element on a non-linear soil medium, which is able to resist compression only. Information on the soil-pile interaction and the stress-strain relationships for concrete and steel is required in order to calculate the response of the pile. The soil-pile interaction is assumed to follow a P-y curve proposed by Yan and Byrne. The formation of gaps between pile and soil is taken into account in the analysis. Tomii and Sakino's confined concrete model is adopted to determine the stress-strain relationship for the concrete inside steel tube. Steel is assumed to be elasto-perfectly plastic. Numerical examples are presented for a CFT and a Hollow section pile. Variability of pile capacity caused by the uncertainty in soil properties is investigated using the computer program RELAN and a response surface involving six random variables. The cumulative distribution function for maximum pile capacity is calculated for cases with and without correlation between the soil variables.Applied Science, Faculty ofCivil Engineering, Department ofGraduat