为研究高墩大跨非规则桥梁的近、远场地震易损性,建立了典型非规则公路连续刚构桥的理论地震易损性模型.考虑近、远场地震动和桥梁结构参数的不确定性,抽样并生成桥梁近、远场地震易损性分析的模型样本库,利用Open Sees软件对模型样本库进行非线性动力时程分析,获得结构动力响应.而后在确定桥梁各易损构件损伤指标的基础上,采用概率地震需求分析方法建立了桥梁各构件近、远场地震易损性曲线并进行对比分析.分析结果表明:非规则桥梁结构的易损性情况与地震动频谱特性、结构非规则性密切相关,各构件近场地震动损伤概率明显高于远场.将地震动按断层距分组进行桥梁地震易损性分析是必要的.获得的易损性曲线可用于评估非规则桥梁的抗震性能,并为震后桥梁损伤评估提供依据.
In order to carry out the near and far-field seismic vulnerability,the seismic vulnerability model of a certain typical irregular highway continuous rigid frame bridge of China was created. Considering the uncertainty of near and far-field earthquake and bridge parameters,by adopting sampling method,the model sample database was generated to carry out bridge seismic vulnerability analysis. In order to obtain the structural near and far-field dynamic response respectively,every model in the database was calculated by using nonlinear time history analysis by using the software such as Open Sees. And the pier and bearing damage index were obtained. Then based on the above studied results,and then the near and far-field fragility curves of bridge dangerous members were obtained by using the probabilistic seismic demand analysis method and then a comparative study analysis for near and far-field seismic vulnerability for the structural damage state was determined. The results showed that,the vulnerability condition of the bridge component was closely related to spectral characteristics of ground-motion and irregular structure,and the near-field damage probability was significantly higher than the far-field 's; so it was very necessary to carry out vulnerability research according to near and far fault ground motion. Finally the fragility curves obtained can be used to evaluate the seismic performance of irregular bridges,and can provide the basis for post-earthquake damage assessment.