【摘要】 城市桥梁在户外各种不利环境因素的影响下，结构材料的耐久性能会发生退化，以致出现混凝土强度降低、钢筋锈蚀等耐久性病害，导致桥梁结构的安全性和可靠性逐渐下降。以某典型城市高架桥为例，基于混凝土结构耐久性理论和城市的限载政策，结合现场检测、实地交通调查结果，分析了桥梁结构的时变抗力和荷载效应的变化规律，最后，推算了桥梁控制截面抗弯承载能力可靠性功能函数的失效概率，并对其可靠度进行了评估。该研究方法为各地城市桥梁的可靠性评估、维修养护、交通荷载限载政策等提供借鉴和参考。更多还原

【Abstract】 Under the attack of various aggressive environmental factors, the durability of material degrades,which leads to the reduction of concrete strength, steel bar corrosion and other durability diseases, resulting in the gradual decline of the safety and reliability of urban bridges. A typical city viaduct was taken as an example,based on the durability theory of concrete structures and the load limit policy of city, combined with the results of in-situ inspection and traffic survey, the time-varying load bearing capacity and load effect of the bridge structure were analyzed, and the failure probability was calculated by referring to the reliability function of the bridge’s control sections, and then the reliability was evaluated. The research method provides reference for the reliability assessment & maintenance of urban bridges and the formulation of traffic load limit policy.更多还原