The seismic performance of a steel pier of box section was studied through low-cycle cyclic testing. The damaged specimens were repaired by filling with concrete and welding steel plates. The low-cycle cyclic test was then repeated. The effects of repairs were investigated by comparison of failure mode, energy dissipation performance, and ductility before and after repair. To supplement the data, the influence of different factors on the seismic bearing capacity and ductility of steel piers were analyzed by finite element method. The repair effects were compared by threshold of the displacement from the experiment. Based on the displacement angle response of the nonlinear dynamic time history analysis, the seismic performance is checked. The results show that repair had favourable effects on the damaged specimens. The horizontal bearing capacity and ductility of the specimens filled with concrete are significantly enhanced. Reinforcement by steel plates can increase the ductility and cumulative energy dissipation of the steel pier. An axial compression ratio of 0.2 and a concrete filling ratio of 30% are suggested. The horizontal bearing capacity can be improved by increasing the steel strength while the concrete strength shows little effect. The angular displacement from nonlinear dynamic time-history analysis was less than the test threshold, so the existing methods used for seismic performance verification are safe.

中文翻译：

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箱形截面钢墩地震损伤影响因素及修复效果

通过低周循环试验研究了箱形截面钢墩的抗震性能。损坏的试样通过填充混凝土和焊接钢板进行修复。然后重复低循环循环测试。通过比较修复前后的失效模式、能量耗散性能和延展性来研究修复的效果。为补充数据，采用有限元法分析了不同因素对钢墩抗震承载力和延性的影响。通过实验位移阈值比较修复效果。基于非线性动态时程分析的位移角响应，检验了抗震性能。结果表明，修复对受损标本具有良好的效果。混凝土填充试件的水平承载力和延性显着增强。钢板加固可以增加钢墩的延展性和累积耗能。建议采用 0.2 的轴压比和 30% 的混凝土填充率。水平承载力可以通过提高钢筋强度来提高，而混凝土强度影响不大。非线性动力时程分析的角位移小于试验阈值，因此现有的抗震性能验证方法是安全的。2 建议混凝土填充率为 30%。水平承载力可以通过提高钢筋强度来提高，而混凝土强度影响不大。非线性动力时程分析的角位移小于试验阈值，因此现有的抗震性能验证方法是安全的。2 建议混凝土填充率为 30%。水平承载力可以通过提高钢筋强度来提高，而混凝土强度影响不大。非线性动力时程分析的角位移小于试验阈值，因此现有的抗震性能验证方法是安全的。