节段拼装桥墩撞击试验研究与数值分析

This study investigated differences in anti-collision performance between precast segmental piers and overall cast-in-place piers, and explored the impact responses and failure modes of precast segmental piers subjected to impact. A reduced-scale model was used, and the dynamic time history response curves of the precast segmental pier and overall cast-in-place pier were obtained through a horizontal impact test. The failure modes of the piers under different impact velocities were observed. The dynamic responses of piers with different structures under impact, such as impact force and displacement, were compared and analyzed. A nonlinear finite element (FE) model of pier impact was established and a numerical simulation of the impact responses and failure modes of piers was carried out. The reliability of the results was verified by experimental test results. The influence of impact height and prestress value on the dynamic response of segmental piers were analyzed by the parameter analysis method. The research results show that under impact, the failure mode of the overall cast-in-place pier changes from tension bending failure to oblique shear failure at the bottom of the pier, and for the segmental piers, the shear slip and concrete crushing occur mainly in the impact segment. Compared with the overall cast-in-place piers, the peak impact force of the segmental pier decreases by 21.25% and the impact duration increases by 147.62%. At the same time, the segmental pier shows stronger deformation ability and energy dissipation ability, but fails to show good self-reset ability, increasing the local damage of concrete. The FE results are in good agreement with the test results, which verifies the correctness of the FE model. Based on the FE model of the precast segmental pier, the impact height and prestress value have less impact on the impact force, but the prestress value and impact height have a significant impact on the deformation and stiffness of the entire pier, respectively. Therefore, the impact height and prestress value should be considered comprehensively in the anti-collision design of segmental piers to ensure the reliability and safety of the structure.