利用等效塑性铰模型对Park-Ang双参数地震损伤模型的改进

A Modified Park-Ang Seismic Damage Model Based on Equivalent Plastic Hinge Model

Park-Ang双参数地震损伤模型近似考虑了首次超越破坏和塑性累积损伤破坏联合作用的破坏机理,兼顾了最大变形和能量两种破坏准则,在基于性能的抗震设计中受到关注.既有的Park-Ang改进模型（M-Park-Ang模型）通过引入低周反复荷载作用下钢筋混凝土墩柱构件疲劳寿命方程和与加载路径有关的能量项加权因子,并结合构件极限滞回耗能与位移延性系数的关系,已能近似考虑加载路径的影响.M-Park-Ang模型引入了固定的临界位移延性系数以通过能量项考虑低周疲劳损伤效应,从而使大剪跨比墩柱试件的适用性受到了限制.本文利用墩柱拟静力试验数据,基于等效塑性铰模型对M-Park-Ang模型进行了修正,将临界位移延性系数与截面曲率延性系数相联系,使改进的M-Park-Ang模型（M-Park-Ang模型（N））能够考虑截面层次的破坏机理.墩柱试验结果验证表明,当试验试件尚未达到中等破坏状态时,M-Park-Ang（N）模型对其损伤的评估结果略偏小;而一旦进入中等破坏阶段以后,M-Park-Ang（N）模型的计算结果能体现试件破坏过程快速增长的趋势;M-Park-Ang（N）模型考虑墩柱剪跨比影响计算临界位移延性系数,对不同高度墩柱都具有较好的适应性.

The comprehensive function of first passage and cumulative damage effect can be considered approximately in the Park-Ang damage model which combines the deformation and energy damage criterions and more attention has been paid to it in the performance based design. The existed modified Park-Ang damage model,named as M-Park-Ang damage model,can take into account of the effects of loading path on damage by introducing the low-cycle fatigue life equation,energy weighted coefficient and the correlations between the ultimate hysteretic energy and the displacement ductility factor of RC specimens. But its applicability is limited when used to the RC specimens with large aspect ratios because of the use of the fixed critical displacement ductility factor in the calculation of the model. Based on the quasi-static tests of RC bridge columns,the M-Park-Ang damage model is further modified（named as M-Park-Ang（N） damage model） on the basis of equivalent plastic hinge model in this study. The correlation between the critical displacement ductility factor and the sectional curvature ductility factor is built to consider the failure mechanism in sections of the plastic zone of RC specimens. The results show that the damage indices of RC specimens are some little small by the M-Park-Ang（N） damage model when the damage is minor. However,the trend of rapid growth of damage in the end of the test loading process can be evaluated once severer damage occurs. As the critical displacement ductility factor is calculated according to the aspect ratio of the RC specimen the M-Park-Ang（N） damage model can be applicable for the columns with different heights.