Experimental investigation of the seismic control of a nonlinear soil-structure system usingMR dampers

Abstract

This paper reports the results of an experimental study conducted to demonstrate thefeasibility and capability of magnetorheological (MR) dampers commanded by adecentralized control algorithm for seismic control of nonlinear civil structures consideringsoil-structure interaction (SSI). A two-story reinforced concrete (RC) frame resting in alaminar soil container is employed as the test specimen, and two MR dampers equipped inthe first story are used to mitigate the response of this frame subjected to various intensityseismic excitations. A hyperbolic tangent function is used to represent the hystereticbehavior of the MR damper and a decentralized control approach for commandingMR dampers is proposed and implemented in the shaking table tests. Only theresponse of the first story is feedback for control command calculation of theMR dampers. The results indicate that the MR damper can effectively reducethe response of the soil-structure system, even when the soil-structure systempresents complex nonlinear hysteretic behavior. The robustness of the proposeddecentralized control algorithm is validated through the shaking table tests on thesoil-structure system with large uncertainty. The most interesting findings inthis paper are that MR dampers not only mitigate the superstructure response,but also reduce the soil response, pile response and earth pressure on the pilefoundation.