90-0013 Secondary Systems in Base-Isolated Structures: Experimental Investigation, Stochastic Response and Stochastic Sensitivity G.D.Manolis, G.Juhn, M.C.Constantinou, A.M.Reinhorn 1990 University at Buffalo 200 PB91-110320 15 This report first describes a series of experiments conducted on the shake table at the University at Buffalo, whereby the performance of secondary systems attached to a scaled, base-isolated six story frame was monitored. The base isolation mechanism consisted of sliding bearings and restoring force springs. This novel passive protection system was designed primarily for the benefit of the superstructure, but the experimental evidence demonstrated that under most circumstances, the secondary systems are also protected. Subsequently, the experimental results were reproduced using an analytical model and extended to cover the base of stochastic input. Finally, the sensitivity of secondary systems to changes in the base isolator's and in the ground model's parameters was numerically investigated, and then extended to cover the case when the aforementioned properties are uncertain. Both experimental evidence and numerical results point to successful base isolation designs of the type examined here, even in the face of uncertain system properties. Base Isolation, Secondary Systems, Stochastic Processes, Seismic Response, Ground Motion, Structural Dynamics, Shaking Table Tests, Teflon Bearings, Multistory Structures, Model Tests, and Dynamic Response.