Free Vibration Analysis of Building Considering Soil Structure Interaction

Abstract

Modeling and design of foundation are always done without considering the effect of stiffness of the soil. In the conventional non-interaction analysis of building frame settlements are calculated without considering the influence of the structural stiffness. Therefore a modeling and interaction analysis of soil structure interaction will help to find soil stiffness and effects of soil structure interaction on structure. In this paper, soil structure interaction analysis of a symmetric space frame of 2 bays in both x and y direction are assessed with SAP 2000 software. The frame is modeled with different storey resting on raft foundation with fixed base and flexible base. Three types of soil, i.e. hard, medium, and soft soil are used for Soil Structure Interaction (SSI) study. MODAL analysis is carried out to illustrate the effects of soil-raft-structure interaction on the response of structures. The Soil is considered as Winkler model and elastic continuum model. The developed methodology is validated with results available in the literature. The effects of SSI on frequency of modal are studied. The comparison is carried out the frame with different base conditions.The frequency of the building was found to be decreased when SSI was considered.