SEISMIC CHARACTERISTICS OF MULTIPLE ISOLATION BUILDING WITH PLURAL ISOLATION STORIES

Abstract

The purpose of this paper is to disclose the fundamental properties of a multiple isolation structure that contains a base isolation story and a middle isolation story. Design formulae of stiffness and damping coefficient of both isolation stories are derived under condition that a base isolation building and a multiple isolation building have the same 1st natural period and damping factor. It is shown that the multiple isolation building designed by the formulae behaves much smaller interstory drift of base isolation story than that of the base isolation building. Eigenvalue analysis and time history analysis to multi-degree-of-freedom models are performed to verify the accuracy of the design formulae.