动力荷载下钢管混凝土墩柱抗震性能极限分析

Ultimate Analysis of Seismic Performance of Concrete-filled Steel Tube Piers under Dynamic Load

为研究钢管混凝土桥墩极限抗震性能,采用Abaqus软件建立圆钢管混凝土桥墩三维实体-壳单元有限元模型。为更准确的描述圆钢管混凝土桥墩的抗震性能退化、震后残余位移变化规律,模型中对混凝土引入裂缝、对钢管引入韧性损伤,进行单向拟静力、单向拟动力、双向拟动力、振动台加载下圆钢管混凝土桥墩抗震性能试验验证。分析结果表明:考虑水平裂缝和钢材韧性损伤影响的钢管混凝土墩柱实体-壳精细有限元塑性抗震计算方法合理,反映循环荷载下钢管混凝土桥墩的滞回曲线“捏拢”效应、塑性大变形阶段承载力退化现象和单、双向动力荷载下钢管混凝土桥墩震后残余位移,也反映钢管混凝土墩柱的界面滑移和约束作用规律;相同地震波作用下全填充钢管混凝土桥墩的地震响应最小,填充混凝土有利于提高桥墩的极限抗震能力。提出适用于双向地震波作用的钢管混凝土桥墩墩顶残余位移与最大位移响应之间的计算公式。

In order to study the ultimate seismic performance of concrete-filled steel tube(CFST)piers,three-dimensional solid-shell finite element models of circular CFST piers were established by using Abaqus software.In the model,cracks in concrete and ductile damage in steel were introduced to consider more accurately the seismic behavior degradation and post-seismic residual displacement variation of CFST piers,and the seismic behavior of CFST piers under unidirectional pseudo-static loading,unidirectional pseudo-dynamic loading,bidirectional pseudo-dynamic loading and shaking table loading was verified by experiments.The results show that the solid-shell finite element plastic seismic calculation method of CFST piers considering the influence of horizontal cracks and steel ductile damage reasonably reflects the"pinching"effect of hysteresis curve,the load bearing capacity degradation in large plastic deformation stage of CFST piers under cyclic loading,the post-seismic residual displacement under unidirectional and bidirectional dynamic loading,and the interface slip and restraint action law of CFST piers.Given the smallest seismic response of fully filled CFST piers under the same seismic wave action,the filled concrete is conducive to improving the ultimate seismic capacity of the piers.Based on the results of finite element parametric analysis,the calculation formula between the residual displacement and the maximum displacement of the top of CFST piers applicable to the bidirectional seismic wave action is proposed.