基于IDA分析的深水高墩连续刚构桥地震损伤评价

Seismic damage evaluation of high pier continuous rigid frame bridge in deep water based on IDA

为研究深水高墩连续刚构桥的地震易损位置及损伤程度,以某库区深水高墩连续刚构桥为对象,采用塑性铰模型,考虑地震动水效应,建立结构非线性有限元模型。采用频数分析法,选取50条典型强震记录为输入,基于IDA分析,从地震易损性分析的角度去评价深水高墩连续刚构梁桥的抗震性能,对比分析了高水位与无水情况下桥墩和支座的整体易损性曲线、桥墩墩身易损位置及其对应的损伤概率分布情况。结果显示:考虑水体时,桥梁构件损伤概率会显著增大,桥梁主墩的易损位置由墩底附近向墩身上部位置移动;支座处的损伤概率在各相应损伤等级中比桥墩高,且相比于主墩,边墩更容易发生损伤;边墩损伤位置主要集中于墩底附近,而主墩损伤位置位于墩底附近及墩身上部。结果表明,抗震设计时,需重点关注以上边主墩易损伤位置的受力及支座位移情况。

In order to study the seismic vulnerable positions and corresponding damage degree of deep-water continuous rigid frame bridge,a nonlinear finite element model of a deep water high pier continuous rigid frame bridge in a reservoir area is established by using plastic hinge model and considering the effect of hydrodynamics.Fifty typical strong earthquake records are selected as input.Based on IDA analysis,the seismic performance of high pier continuous rigid frame bridge in deep water is evaluated from the point of seismic vulnerability analysis by frequency analysis method.And the overall fragility curves of piers and bearings,the vulnerability position of piers and the corresponding damage probability with high-level water and without water are compared and analyzed.The results show that,when considering water,the damage probability of the components of the bridge will increase significantly,and the vulnerable positions of main pier will move from the vicinity of the pier bottom to the upper part of pier;the damage probability of bearings is higher than that of piers in the same damage levels,and the side pier is more vulnerable to damage than that of main pier;the damage position of side pier is mainly concentrated near the bottom of pier,while the damage position of main pier is located at the vicinity of the pier bottom and the upper parts of piers.In seismic design,the stress of the vulnerable positions of the main and side piers,and the displacement of bearings should be paid attention to.