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以一高墩大跨连续刚构桥为例,基于Open Sees程序建立其非线性分析模型。考虑氯离子侵蚀引起的钢筋直径和屈服强度退化,根据截面非线性分析结果探讨了氯离子侵蚀效应对高墩抗震能力的影响。通过单条地震波的非线性时程地震响应,定性地研究了氯离子侵蚀效应对桥梁地震需求的影响。然后输入15条地震波进行多次增量动力分析,采用对构件能力需求比(Demand/Capacity)进行对数回归分析的方法形成了桥梁的时变地震易损性曲线,对高墩桥梁的时变抗震性能进行评估。分析结果表明:氯离子侵蚀效应会导致高墩屈服弯矩下降,而延性能力略有提高;考虑纵筋锈蚀以后,高墩的位移需求和曲率需求则会显著增加;在桥梁全寿命设计基准期内,结构在不同损伤状态的地震易损性随桥梁服役时间增加而增大。
Taking a high pier and a long span continuous rigid frame bridge as an example, a nonlinear analysis model based on Open Sees program is established. Considering the degradation of the diameter and yield strength of reinforced bars caused by chloride ion erosion, the effect of chloride ion erosion on the seismic capacity of high pier is discussed based on the results of nonlinear analysis. Based on the nonlinear time-history seismic response of a single seismic wave, the influence of chloride ion erosion on bridge seismic demand is studied qualitatively. Then input 15 seismic waves to carry out multiple incremental dynamic analysis. Logistic regression analysis of demand / capacity is adopted to form the time-varying seismic vulnerability curve of the bridge, Seismic performance assessment. The results show that the chloride ion erosion effect leads to the decrease of yield moment of high pier and the slight increase of ductility, and the displacement demand and curvature demand of high pier increase significantly after considering the longitudinal reinforcement. In the bridge life cycle design reference period The seismic vulnerability of the structure and the structure in different damage states increases with the service life of the bridge.