Real-Time Dynamic Substructuring Testing of a Bridge Equipped with Friction-Based Seismic Isolators

This paper presents a real-time dynamic substructuring (RTDS) test program that was carried out on a bridge structure equipped with seismic isolators with self-centering and friction energy dissipation capabilities. The structure studied also included bearing units with sliding interfaces providing additional energy dissipation capacity. In the RTDS tests, the seismic isolator was physically tested in the laboratory by using a high performance dynamic structural actuator imposing, in real time, the displacement time-histories obtained from numerical simulations that were run in parallel. The integration scheme used in the test program was the Rosenbrock-W variant and the integration was performed by using the MathWorks's Simulink and an XPC target computer environment. The numerical counterpart included the bridge piers and the additional energy dissipation properties. The nonlinear response of these components was accounted for in the numerical models. The RTDS tests were performed in the direction parallel to the length of the bridge. The effects of various ground motions and the influence of modeling assumptions such as friction and column stiffness were investigated. Finally, the test results were compared to the predictions from dynamic time-history analyses performed by using commercially available computer programs. The results indicate that simple numerical modeling techniques can lead to an accurate prediction of the displacement response of the bridge seismic protective systems studied.