钢-混组合梁斜拉桥极限承载能力分析

Analysis of Ultimate Bearing Capacity of Steel-concrete Composite Girder Cable-stayed Bridge

以一座主跨420m的双工字型组合梁斜拉桥为研究案例,采用ANSYS有限元程序计算斜拉桥在运营阶段的第二类稳定系数,同时对荷载作用下斜拉桥的破坏过程进行详细分析。对比运营阶段六种典型加载工况,得出恒载+纵向百年风作用对结构的承载能力最不利。成桥阶段,组合梁斜拉桥结构的失效路径为:桥塔处钢主梁先屈服,而后索塔与横梁交界处混凝土压碎区域不断扩大,斜拉索屈服断裂,最后全桥破坏。对全桥结构的破坏过程进行研究,为同类桥梁的设计与承载能力评估提供参考。

Taking a double I-shaped composite girder cable-stayed bridge with a main span of 420m as a research case, the second stability coefficient of the cable-stayed bridge in the operation stage is calculated by using the ANSYS finite element program, and the failure process of the cable-stayed bridge under load is analyzed in detail. Compared with the six typical loading modes in the operation stage, the dead load+longitudinal centennial wind effect is the most unfavorable to the bearing capacity of the structure. At the completion stage, the failure path of composite beam cable-stayed bridge structure is: The steel main beam at the bridge tower first yields, and then the concrete crushing area at the junction of the cable tower and the beam continues to expand, the cable plastic fracture, and finally the whole bridge is damaged. The failure process of the whole bridge structure is studied to provide reference for the design and bearing capacity evaluation of similar bridges.