COUPLED SOIL-PILE-STRUCTURE INTERACTION ANALYSIS UNDER SEISMIC EXCITATION

Seismic soil-pile-structure interaction has been an area of limited re search, and most of the existing work adopts the conventional approach of soil-structure interaction analyses in which the problem is solved by superposition of kinematic and inertial interaction. This multiste p approach is often time consuming. The present study focuses on a cou pled finite element-boundary element type approach, where the entire p roblem domain is solved in a single pass. The problem is cast in the f requency domain and a substructured method of analysis is adopted by i nterfacing the superstructure and the foundation at the foundation cap level. The free-field seismic response is calculated by an equivalent -linear method that is widely used. The formulation allows for multipl e supports with varying excitations. Coupling of the problem allows on e to construct transfer functions for various degrees of freedom in th e structure including the effects of interaction. A number of examples presented in this paper demonstrate the utility of the method in solv ing problems involving bridge piers and building frames.