Dynamic Analysis of Footings on Layered Media

A finite element formulation for the dynamic analysis of circular footings resting on or embedded in layered soil strata is presented. The formulation provides excellent results, accurately reproducing the lateral radiation effects through a consistent energy transmitting boundary, which is an extension of that suggested by Waas and Lysmer for two-dimensional problems. Because the boundary can be placed directly at the edge of the footing without loss of accuracy, it also provides savings in storage requirements and time of computation over other solutions. The analysis must be performed in the frequency domain; arbitrary transient loading conditions are then handled using fast Fourier transformation techniques.