Response control of seismic isolated buildings using developed passive-switching oil damper with Bi-flow mechanism

The authors have developed a passive-switching oil damper for seismic isolated structures that can control the displacement response of isolation layer within design limit under extreme earthquake events while maintains the acceleration response of superstructure in acceptable level in major and moderate earthquake events. The fundamental performance characteristics of the damper are experimentally tested. Then, the earthquake responses of a seismically isolated building model with the damper installed are simulated. The simulated results show that, with the aid of the damper, the building model would reduce the acceleration responses both to major and moderate quakes, and the isolation layer would not exhibit such displacement responses to extremely large quakes as to exceed the clearance gap. In addition, the rotation resulting from unbalanced switching of the dampers installed in opposite ends of the building is assessed. The rotational responses are confrrrned to be in small level.