基于优化串-并联模型的钢桁拱桥系统易损性研究

Research on vulnerability of steel truss arch bridge system based on optimized series parallel model

为研究适用于钢桁拱桥系统易损性的分析方法,采用串联模型、简单串-并联模型、优化串-并联模型3种可靠度模型,基于一阶界限法分别绘制系统易损性曲线、系统损伤超越概率差值曲线以及损伤控制组件曲线。研究结果表明:串联模型不能考虑主、次要构件在系统易损性中的比重,简单串-并联模型能考虑主、次要构件的比重,但往往不能代表结构真实的失效模式,而优化串-并联模型既能代表考虑主、次要构件的比重,又能代表真实的失效模式。设计地震动下串联模型、简单串-并联模型分别会高估和低估系统轻微损伤超越概率,这与实际情况不符。串联模型导致系统严重损伤的误差最大,简单串-并联模型导致系统中等损伤的误差最大。不同可靠度模型的系统损伤超越概率较大的直接原因是不同可靠度模型的系统易损性的控制组件不同。因此建议对钢桁拱桥系统易损性分析时宜采用优化串-并联模型。

In order to study the vulnerability analysis method of steel truss arch bridge system,three reliability models were adopted,including series model,simple series parallel model and optimized series parallel model.The system vulnerability curve,the system damage exceeding probability difference curve and the damage control component curve were drawn respectively based on the first-order boundary method.The results show that the series model cannot consider the proportion of primary and secondary components in the vulnerability of the system.The simple series parallel model can consider the proportion of primary and secondary components,but it cannot represent the real failure mode of the structure.The optimized series parallel model not only represents the proportion of primary and secondary components,but also represents the real failure mode.The series model and the simple series parallel model will overestimate and underestimate the overestimationprobability of slight damage of the system under ground motion, which is not in accordance with the actualsituation. The error of serious damage caused by series model is the largest, and that of moderate damage causedby simple series parallel model is the largest. The direct reason for the greater overestimation probability ofsystem damage in different reliability models is that the control components of system vulnerability of differentreliability models are different. Therefore, it is suggested that the optimized series parallel model should beadopted in the vulnerability analysis of steel truss arch bridge system.