RESPONSE OF BASE-ISOLATED STRUCTURES TO RANDOM EARTHQUAKES

Responses of a base-isolated shear beam structure with several base isolation sys-tems, including the laminated rubber bearing, the resilient-friction base isolator with and without sliding upper plate, and the EDF system, subject to random earthquake excitations are studied. The method of time-dependent equivalent linearization is uti-lized and the mean-square response statistics of the base-isolated shear beam structure are evaluated. Statistically estimated peak responses of the base-isolated structure are compared with the response spectra for the actual earthquake accelerograms. Compar-isons of the results with those for the fixed-base structure show that the base isolation systems can, in general, be highly effective in reducing the mean-square responses of the superstructure.