双层钢箱-混凝土组合墩双向地震损伤模型研究

Study on bidirectional seismic damage model of double-skin steel-concrete composite box piers

既有的地震损伤模型大多基于水平单向拟静力试验得到的,未考虑结构或构件在双向地震作用下水平两个方向相互耦合作用所导致的性能退化加剧,计算所得的损伤因子不能体现双向耦合影响引起的损伤加剧。本文基于Kumar-Usami地震损伤模型,进一步考虑不同位移幅值下的有效耗能影响,提出了双层钢箱-混凝土组合墩双向地震损伤模型,并利用水平双向拟静力试验得到的双向耦合作用下的变形和耗能数据对双层钢箱-混凝土组合墩的双向地震损伤模型参数进行标定。研究结果表明:(1)该地震损伤模型可以反映加载顺序、加载历史及不同加载位移权重的有效耗能等对双层-钢箱混凝土组合墩地震累积损伤的影响;(2)提出了双层钢箱-混凝土组合墩不同程度损伤的指标限值,给出了考虑双向地震作用下水平两个方向耦合作用的总体损伤计算表达式,模型计算结果与试验吻合良好。本文建议的双向地震损伤模型可供双层钢箱-混凝土组合墩基于性能的抗震设计与损伤评估使用。

The existing seismic damage models are mostly obtained only from one-directional quasi-static testing,without considering the increased performance degradation of structure or components caused by bidirectional horizontal mutual coupling effects under bidirectional earthquake,which lead to that the calculated damage factor cannot reflect the increased damage caused by bidirectional coupling effects. In this paper,based on the current Kumar-Usami double variables seismic damage model,a modified bidirectional seismic damage model was proposed for the double-skin steel-concrete composite box（ DSCB） piers,considering the effects of effective energy dissipation under different displacement amplitudes. In addition,the parameters of the new bidirectional seismic damage model were calibrated by using the deformation and energy dissipation data under bidirectional coupling effects obtained by horizontal bidirectional quasi-static testing. It can be concluded from the analysis results that ：（ 1） the proposed seismic damage model can reflect the seismic cumulative damage effects of some factors,such as the order of load-ing,the loading history and the effective energy dissipation of different loading displacement weight of DSCB piers;（ 2） the damage index limits of DSCB piers under different damage conditions were presented,and the overall cumulative damage calculation expression was also proposed considering bidirectional coupling effects under bidirectional earthquake loading,and the model calculation results are compared with the experimental data well. The seismic damage model proposed in this paper can be used for the seismic design and damage assessment of the DSCB piers under strong earthquake actions.