Review of Dynamic Response and Pier Damage Mechanisms in Girder Bridges Under Bidirectional Seismic Excitations: Critical Role of Vertical Components in Near-Field Effects

This paper systematically reviews bridge structural dynamics and pier damage mechanisms under seismic excitation over recent decades, addressing four key aspects: (1) the structural response of simply supported bridges subjected to horizontal seismic forces and corresponding damage in shear keys and piers; (2) the impact of near-fault vertical ground motion on vertical constraint degradation and its contribution to pier damage; (3) the failure mechanisms of piers under bidirectional coupled seismic excitations; (4) recent advances in innovative design concepts, structural configurations, and material applications for seismic-resistant piers. Eventually, the limitations of current research are identified, and potential future research directions and methodologies are proposed.