Seismic Control of Base Isolated Structures Using Novel Magnetorheological Elastomeric Bearings

This paper presents the performance of a novel semi-active variable stiffness magnetorheological elastomer (MRE) bearing for seismic mitigation of civil structures. The proposed MRE bearing consists of a traditional steel-rubber vibration absorber, as the passive element, and a MRE with a controllable stiffness behavior. The controllability of the prototype MRE bearing is investigated experimentally under quasi-static and dynamic shear tests. The behavior of the MRE bearings is modeled using a phenomenological method which includes Bouc-Wen hysteresis element. The results show that both the single MRE bearing and an integrated system with four MRE bearings can increase the stiffness, damping, and hysteresis effect with a control input electric current. In addition, to demonstrate the feasibility of utilizing the MRE base isolation for seismic control of structures, a 1:16 scaled, three-story building supported by four MRE bearings, is constructed. A feedback control system is used to validate the effectiveness of the controlled MRE bearing in reducing structural responses. The scaled El-Centro seismic earthquake excitation is applied to the isolated building. The response of the controlled building shows significant reduction in displacement and acceleration compared to those of passive and on-state conditions.