在役钢筋混凝土桥梁承载力分析方法

Analysis Method for Carrying Capacity of Existing RC Bridges

针对在役钢筋混凝土桥梁的承载力问题,提出了一套完整的承载力分析流程。首先按现行设计规范利用有限元软件计算桥梁荷载效应;其次考虑混凝土碳化、氯离子侵蚀、钢筋锈蚀及钢筋/混凝土黏结性能退化等因素,计算其实际承载力并进行验算,其中氯离子侵蚀采用细胞自动机原理进行模拟;然后对影响承载力的各不确定性因素进行敏感性分析。最后以天津市中心城区某超期服役钢筋混凝土梁桥为例,说明该承载力分析流程的计算过程,并对关键截面进行承载力退化过程分析。

For the carrying capacity of the existing RC bridges, this paper puts forward a complete set of carrying capacity analysis flow. Firstly, the bridge load effect is calculated by using the finite element software according to the current design code, secondly, the factors of concrete carbonation, chloride ion corrosion,rebar corrosion and rebar/concrete bond property degradation are considered. Its actual carrying capacity is calculated and checked, in which the chloride ion corrosion is simulated by using cellular automata principle.Then, the sensitivity analysis of the uncertain factors affecting the carrying capacity is carried out. Finally,taking a RC bridge with the extended service in the central urban area of Tianjin as an example, this paper illustrates the calculation process of the carrying capacity analysis flow and analyzes the degradation process of carrying capacity for the key sections.