特殊复杂场地条件下桥梁结构地震易损性研究现状及发展趋势分析

Summary and prospect of research on seismic vulnerability of bridge structures under special complex site conditions

考虑到桥梁地震易损性分析中场地条件影响的不确定性,本文主要针对流水冲刷环境、可液化场地、近断层场地、氯盐侵蚀环境和冻土场地等特殊复杂场地条件对桥梁结构地震易损性的影响特征和机理进行了总结归纳,并提出了尚待进一步研究的关键问题。结果表明:特殊场地地震响应的复杂性和桥梁结构的特殊性相叠加,给复杂场地条件下桥梁的抗震性能评估带来了极大的挑战。在对特殊场地条件下的桥梁结构进行易损性分析时,综合考虑多个地震动强度指标和损伤指标可以更好地表征地震动输入和结构的损伤状态。因此,如何科学地衡量各种不确定性因素的影响,继而提出合理的等效简化分析模型,并建立考虑场地效应的桥梁系统易损性曲线有待进一步研究。此外,考虑结构全寿命周期和气候变化背景,从概率角度评估特殊复杂场地条件下桥梁的抗震性能,对既有桥梁的改造和新桥的设计具有重要的指导意义。

Considering the uncertainty of site conditions in bridge seismic vulnerability analysis,this paper summarizes the seismic vulnerability analysis of bridge structures under special complex site conditions(mainly included water scouring environment,liquefiable site,near fault site,chloride erosion environment and frozen soil site),and the key problems need to be further studied are proposed.The results show that the complexity of seismic response of special sites and the particularity of bridge structures combined together,which brings great challenges to the seismic analysis of bridges under complex site conditions.In the vulnerability analysis of bridge structures under special site conditions,it is better to consider multiple ground motion intensity indexes and damage indexes together so as to get better ground surface vibration input and structure damage state.Thus,it needs further research to measure the influence of various factors,then put forward reasonable equivalent simplified analysis model,and establish the vulnerability curve of bridge systems.Furthermore,it is of great significance to take the whole life cycle and the background of climate change into consideration,so as to evaluate the seismic performance of bridges under special complex site conditions from the perspective of probability.