Modification of a Sloped Rolling-type Isolation Bearing with Stepwise Variable Designs

Modification of a Sloped Rolling-type Isolation Bearing with Stepwise Variable Designs

In this study, we numerically investigated the horizontal displacement control performance of sloped rolling-type seismic isolators with the same horizontal control performance by passively varying parameters in a stepwise pattern, and keeping others variables constant. The first design incorporated stepwise increased sloping angles and a stepwise decreased damping force with increasing horizontal isolation displacement. The second design used the opposite philosophy, in which the stepwise sloping angles were decreased and the stepwise damping force was increased with increasing horizontal isolation displacement. A series of numerical results show that for sloped rolling-type seismic isolators designed with a constant sloping angle and damping force, larger damping forces (smaller sloping angles) generally correspond to a smaller horizontal maximum and a larger residual displacement response. In summary, to ensure acceptable displacement control performances without sacrificing acceleration control performance under diverse seismic demands, we compared designs with constant parameters. Adopting the second design appears to be a better choice.