Response Spectra Analysis of Base Isolated Building

Abstract

Conventionally, seismic design of building structures is based on the concept of increasing the resistance capacity of the structure against earthquake by employing, for example, the use of shear walls, braced frames, or moment resistant frames. However, these traditional methods often results in high floor accelerations for stiff buildings, or large inter-storey drifts for flexible buildings. Because of this, the building contents and nonstructural components may suffer significant damage during a major earthquake, even if the structure itself remain basically intact. In order to minimize inter-storey drifts, in addition to reducing floor accelerations, the concept of base isolation is increasingly being adopted. Base isolation also been referred to as passive control as the control of structural motions is not exercised through a logically driven control system. This paper represents the analytical approach to find the response of the base isolated structures using concept of response Spectrum defined in IS: 1893 – 2002 (Part I). Because of the involvement of large parameters, use of software is inevitable for the solution of base isolated structures. However, this paper shows analytical way of solution for small SDOF building structure. The concept developed hereby can be extended further for large size building structures.