北方某大跨钢管混凝土拱桥动力特性分析

Dynamic characteristic analysis of long-span concrete-filled steel tubular arch bridge in North China

针对北方某钢管混凝土拱桥东拱肋拱顶合拢高度比设计标高(35.017m)低0.30m,西拱肋拱顶合拢高度比设计标高低0.44m的问题,采用ANSYS软件对其建立空间有限元计算分析模型,并用子空间迭代法对结构进行了模态分析,得到了结构的自振频率和振型。由计算结果可知:该拱桥横向刚度小于纵向刚度,结构横向可能成为薄弱环节;结构的振型多次出现局部振动的特征,表明拱肋和桥面连接较弱。计算结果对该拱桥的检测、维修、改造具有重要价值。

The joint heights of the east and west arch ribs of one concrete-filled steel tubular （CFST） arch bridge located in North China are 0.30 and 0.44 meters lower than the design elevation, respectively, in order to solve the problem of the joint heights the software ANSYS is adopted to establish the finite element model of the structure and the subspace method is used to analyze the structural modal characteristics, then natural frequencies and mode shapes of the structure are obtained. By analyzing the dynamic behavior of the structure, the lateral rigidity is lower than the longitudinal rigidity, and local vibration has appeared many times in mode shapes, and it is obvious that the link between arch rib and deck is weak. The results obtained are available for the detection, maintenance and reconstruction of the structure in practice.