Parametric Study of Superelastic-Sliding LRB System for Seismic Response Control of Continuous Bridges

Abstract

To enhance the normal service adaptability and seismic resistance performance of isolation continuous bridges, a superelastic-sliding lead rubber bearing (SSLRB) isolation system was developed by incorporating shape memory alloy (SMA) wires with sliding-LRB. A parametric design method was proposed to design the SMA wires in the SSLRB system for the optimum performance of bridges in terms of suppressing the displacement response and in the meantime limiting the increment of the force response in piers. A parametric investigation was performed to obtain the SMA parameters as a critical part of designing the SSLRB system. The seismic responses of bridges isolated by SSLRBs were investigated and compared with those of the same bridges with the conventional sliding-LRBs. The efficiency of the SSLRB system was further demonstrated by conducting a case study. Results verified the effectiveness of the suggested method for optimizing the parameters of SMA wires and the SSLRB system for response control. The displacement responses (e.g., residual displacement) can be effectively mitigated, and in the meantime the seismic demand of the piers can be suppressed. This study demonstrates that the proposed SSLRB isolation system can maintain stable re-centering performance against near-fault earthquakes.