PERFORMANCE EVALUATION OF A SEISMICALLY ISOLATED BRIDGE WITH SPHERICAL SLIDING BEARINGS BASED ON DYNAMIC DATA

Abstract

 In recent years, the seismic retrofitting of bridges through the replacement of existing steel bearings with isolation bearings has become increasingly common across Japan. Spherical Sliding Bearings (SSBs) are particularly notable for their reduced structural height, which minimizes construction space requirements compared to conventional laminated rubber bearings. The seismic isolation performance of SSBs is governed by their elongated period and energy absorption capacity, which are determined by the stiffness of the bearings and the friction coefficient between the sphere and the slider. This study proposes a novel performance assessment method for SSBs in bridges, utilizing dynamic data and Bayesian estimation techniques. Specifically, an adaptive unscented Kalman filter (AUKF) is employed to estimate key performance indicators and the restoring force characteristics of SSBs. The feasibility of the proposed method is validated using experimental data from shake table tests on an isolation bridge model.