Parameters Affecting Dynamics of Three-Dimensional Seismic Isolation

Seismic base isolation systems are mainly used to reduce seismic demands and minimize earthquake effect on structure performance. In this study, the fundamental dynamic response of structures with three-dimensional (3D) isolation systems is explored using a simplified rigid block model. A parametric study is carried out to evaluate the effect of different site conditions, structure properties and 3D isolation parameters on structure and bearing response. The results show that the acceptable range of 3D isolation periods is 0.5–1.0 s for vertical direction with horizontal isolation period around 3–4 times the vertical period and 20% damping in both directions.