Seismic behaviour of the curved bridge with friction pendulum system

The friction pendulum system (FPS) is a crucial tool for seismic protection. However, effectiveness in curved bridges, especially controlling torsional moments (TMs), has not been thoroughly assessed. This study evaluates how well a continuously curved bridge equipped with FPS performs under various earthquake loadings. The study assesses FPS efficiency, considering factors like multidirectional impacts, seismic motion strength, incidence angle variations, and ground motion characteristics. Finite element modeling of the bridge structure was conducted using SAP2000v20 Finite Element Analysis software. Three earthquake scenarios (near fault, far fault and forward directivity) were considered. The study also examines the bidirectional behavior's impact on the bearing and pier interaction. A sensitivity analysis was performed for the bridge response concerning bearing design parameters for each earthquake scenario. The results show that FPS bearings significantly reduce the bridge's seismic response. Bidirectional excitation was found to be critical for curved bridges, increasing displacement compared to unidirectional motion. Under unidirectional excitation, the isolated bridge with FPS reduces TMs by approximately 26-54%. In bidirectional excitation, FPS remains effective, reducing TMs by about 14-43%. This study underscores the importance of FPS in enhancing seismic resilience, particularly in controlling torsional responses in complex, curved bridges in varying seismic conditions.