外置耗能器对自复位预制RC桥墩抗震性能的影响研究

A novel type of self-centering prefabricated bridge column (SC-PBC) was developed based on the first self-centering (SC) bridge in China, the Huangxu road overpass bridge of the Beijing-Taiwan expressway (Beijing section), combined with the characteristics of the self-centering and fabricated structures. Three groups of external energy dissipation devices (EDDs) with contribution rates of 0, 20%, and 40% to the lateral strength of the bridge column were designed and manufactured. A horizontal quasi-static test of the three groups of SC-PBC with EDDs was carried out. The seismic performance and influence of the EDDs on the SC-PBC were evaluated by the deformation and damage evolution process of the bridge columns, the force-displacement hysteresis behavior, skeleton curve, energy dissipation capacity, tension force of the prestressing tendons, residual displacement, joint opening, and compression zone height at the pier bottom. The results showed that: obvious high-order buckling behavior occurs in the energy dissipation section of the EDD during loading, revealing obvious energy dissipation; the hysteretic curves of the SC-PBC model with external EDDs exhibit an obvious "flag" shape; with the increase of the contribution rate of the lateral strength of the EDDs, the hysteretic curves of the piers are plumper, and the energy dissipation ability and lateral strength of the pier are obviously improved. When the lateral displacement is 3.5%, the lateral strength of the SC-PBC with external EDDs does not decrease significantly, which indicates good ductility; the tension force of the axial prestressing tendons in the SC-PBC increased linearly with an increase in the horizontal loading displacement at the top of the bridge column; the initial tensile force of the prestressing reinforcement of more than 70% of the nominal yield strength is not recommended; and to ensure the small residual displacement of the SC-PBC, EDDs with a contribution rate of more than 40% to the lateral strength are not recommended. This research provides a reference for the structural design, numerical model validation, and engineering practice of the SC-PBC.