Development of simple mechanical on-off damper for base-isolated buildings subjected extreme earthquakes

This paper proposes a simple mechanical on-off damper that can change the damping force depending on the response displacement and response velocity. The on-off damper reduces the damage to seismic-isolated structures that undergo excessive deformation during huge earthquakes, without lowering the performance of the seismic-isolation system during design earthquakes. A numerical analysis method for base-isolated structures in which the isolation layer is equipped with our on-off damper, and also considers collisions with stoppers, is expatiated. A shaking table experiment was conducted, and the results were compared with the numerical analyses. The test results agree approximately with the numerical analysis results. © 2021 Architectural Institute of Japan. All rights reserved.