Abstract
An effective method of carrying out a time-domain finite element analysis of footings subjected to dynamic axial load is presented. Infinite elements are used to model radiation effect in the horizontal direction. This allows the vertical boundary to be placed as close to the footing as desired. The restrictions are that the domain outside the radiation boundary must be horizontally layered and behave linearly during the loading. Shape functions for the infinite elements are obtained from frequency-domain analytical mode shapes, but in such a way that they are valid in time domain. The soil deposit is assumed to rest on a fixed horizontal plane. In the study reported herein, the entire domain is assumed to be isotropic and linear visco-elastic. The validity of the method is verified by comparing the results with those obtained by the standard finite element method with a vertical boundary placed sufficiently far from the footing.
