Nonlinear analysis of a large bridge with isolation bearings

As a part of the California Toll Bridge Seismic Retrofit Program, a global nonlinear time history analysis of the Benicia-Martinez Bridge was conducted using ADINA. A key component of the retrofit strategy was the implementation of friction pendulum bearings. Proper application of the frictional contact surface and the simulation of the restoring force of the bearing were critical to the evaluation of the proposed seismic retrofit. Various local models of the bearing system were developed to study its response and sensitivity to the modeling parameters. Responses of the ADINA friction pendulum bearing representation were compared to those of other nonlinear codes. The behavior predicted by the system of elements used in ADINA for the friction pendulum bearing produced results that matched very closely with other programs. Other important issues for analyzing the Benicia-Martinez Bridge are also discussed.