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通过选取我国近海某一隔震桥梁为算例,引入氯离子侵蚀的影响,考虑桥台、板式橡胶支座、桥墩等构件损伤,提出了考虑各构件地震需求相关的全桥系统易损性计算方法。首先对混凝土结构中钢筋锈蚀机理及过程展开了研宄,建立了钢筋屈服强度及直径的退化公式;其次考虑了地震动和结构的不确定性,最终分别基于一阶可靠度理论和Monte Carlo抽样形成了全桥的系统易损性曲线。计算结果表明:对于隔震桥梁而言,板式橡胶支座最容易发生损伤破坏;全桥系统比任何单一构件都更容易发生破坏,采用全桥易损性曲线评价桥梁的抗震性能更加合理;基于Monte Carlo抽样考虑各构件地震需求相关得到的全桥系统真实易损性曲线才能真正反映结构体系的实际抗震性能。
By taking a seismic isolation bridge in the offshore of our country as an example, the influence of chloride ion erosion is introduced. Considering the damage of bridge abutments, rubber bearings and bridge piers, the vulnerability calculation of full bridge system method. Firstly, the corrosion mechanism and process of steel bars in concrete structures were studied, and the degradation formula of yield strength and diameter of steel bars was established. Secondly, the uncertainty of seismic motion and structure was considered. Finally, based on first-order reliability theory and Monte Carlo sampling Formed a full bridge system vulnerability curve. The results show that the rubber bearing is the most vulnerable to damage and damage to the isolated bridge. The failure of the full bridge system is more likely than that of any single component. It is more reasonable to evaluate the seismic performance of the bridge by using the full bridge vulnerability curve. The Monte Carlo sampling considers the true vulnerability curve of the full bridge system in relation to the earthquake demand of each component to truly reflect the actual seismic performance of the structural system.