Seismic performance of a self-centering tall-pier bridge: Experimental and numerical evaluation

Given the advantages of rocking bridges in terms of minor damage and negligible residual deformation after strong earthquakes, this study extends the established self-centering (SC) concept to tall-pier bridges with pier heights exceeding 40 m and evaluates its seismic effectiveness through shake-table testing and numerical simulation, with particular emphasis on the higher-mode effects associated with the distributed mass and flexibility of slender piers. The proposed system incorporates unbonded post-tensioned (PT) tendons at both the top and bottom of the pier to enable prefabricated assembly of the foundation-pier-girder system and to provide stable recentering capacity. Additionally, externally replaceable energy-dissipating (ED) devices are employed to dissipate earthquake-induced input energy. To further enhance global stability, an expanded base is adopted to improve overturning resistance. Experimental and numerical results indicate that the proposed SC system exhibits no significant structural damage or residual deformation after seismic excitation, demonstrating excellent post-earthquake resilience. Moreover, the locally amplified acceleration observed in the middle region of the tall pier, together with the nonlinear displacement profile along the pier height, indicates non-negligible higher-mode participation in the response of the SC tall-pier system.