Seismic response control of a structure isolated by flat sliding bearing and nonlinear restoring spring: Experimental study for performance evaluation

This study presents the outcome of an experimental evaluation of a structure isolated by flat sliding bearing with nonlinear restoring springs. The composite device of flat sliding bearing with nonlinear stiffening springs, which has been proposed recently, has the following advantages: (i) its behavior is similar to that of flat sliding bearing for minor to moderate level of shaking, (ii) for high intensity shaking, the device reduces the peak bearing displacement in comparison to the flat sliding bearing, and (iii) the device minimizes the bearing residual displacement irrespective of intensity of shaking. The experimental study conducted with a steel moment-resisting frame demonstrates that the device is quite effective in reducing the peak and residual bearing displacements. Further, it is found that other parameters such as peak inter-story drift and peak horizontal floor acceleration are not significantly affected by addition of restoring springs. Hence, the proposed system is an ideal candidate for a cost-effective base isolation system.