Chapter Ten - Critical Excitation for Earthquake Energy Input in Soil-Structure Interaction System

Abstract

This chapter discusses the method of critical excitation for earthquake energy input in a soil-structure interaction (SSI) system. It is true that, while the analysis of SSI effects has been focused on the investigation in terms of deformation and force, not much has been done for the investigation in terms of earthquake input energy to the SSI system. This chapter explains a new evaluation method of earthquake input energy to SSI systems. It is an approach in the frequency domain. Because the inertial interaction and the kinematic interaction are well described by frequency-dependent functions, the present approach based on the frequency-domain analysis is appropriate and effective. Especially, it is demonstrated that even SSI systems including embedded foundations can be treated in a simple way. The effects of the foundation embedment on the earthquake input energies to the super-structure and to the structure-foundation-soil system can be clarified systematically. The works by boundary forces on their corresponding displacements defined for various boundaries are utilized in evaluating the energy flow in SSI systems. The evaluation of earthquake input energy in the time domain is suitable for the evaluation of the time history of input energy.