Displacement-based seismic design and analysis of multi-story BRBs equipped in RC tall bridge bents with new hinged column links

Utilizing buckling-restrained braces (BRBs) is a widely accepted approach for the seismic retrofit of double-column reinforced concrete (RC) bridge bents. However, for multi-story tall bents with concrete link beams, the seismic design of BRB parameters across multiple stories is more complex than initially anticipated. In many cases, time-consuming parametric analyses are required to determine the appropriate BRB parameters for these multi-story systems. This study introduces a novel bracing system for multi-story tall bridge bents, combining hinged links and diagonal BRBs. Based on a fundamental formulation for the new system, a direct displacement-based seismic design method is developed, enabling the efficient and straightforward determination of BRB parameters for specified seismic design objectives. A series of practical design steps is presented, demonstrated through design examples, and validated by nonlinear time-history analyses. The results show that the proposed design method is both feasible and efficient, providing a reliable means to determine the BRB parameters for the new bracing system. With these parameters, the desired seismic performance of the tall bridge bents under design earthquakes can be effectively achieved. Furthermore, the method enables accurate predictions of the seismic responses of the designed bracing systems.