EFFECTS OF SOIL - STRUCTURE INTERACTION ON SEISMIC RESPONSE OF A SYMMETRICAL BUILDING

Abstract

Soil-structure interaction (SSI) is an important issue, especially for stiff and massive structures resting on the relatively soft ground, which may alter the dynamic characteristics of the structural response significantly. An analytical approach is considered in this dissertation for the linear analysis of three dimensional dynamic soil-structure interaction of symmetrical building for different structural time period and soil properties, in order to investigate the seismic responses in the time domain. The modeling of the system and its analysis is carried out using ANSYS software. The free-field response and the structural response ignoring and considering soil-structure interaction are obtained for both harmonic excitation and real earthquake time-history records. The results have been evaluated to incorporate the major effects of soil-structure interaction on the seismic response behavior of the building. The results of the study show that for analysis without soil-structure interaction, when the time period of soil and structure get close to each other, the peak response of the building occurs. It is observed that for the considered data, the seismic response of the structure ignoring soil-structure interaction is more than that of with soil-structure interaction Also, the soil-structure interaction effects are considerably reduced with the increase in structural time period. The dynamic characteristics and the seismic response of the building taking interaction into account depend upon stiffness of the structure and the soil stratum. It is also observed that it is very important to consider the soil-structure interaction for the structure situated on soft soils.