Study on Dynamic Characteristics of Long-Span Highway-Rail Double-Tower Cable-Stayed Bridge

The long-span dual-purpose highway-rail double-tower cable-stayed bridge has the characteristics of a large span and large load-bearing capacity. Compared with the traditional cable-stayed bridge, its wind resistance and seismic resistance are weaker, and the dynamic characteristics of the bridge are closely related to the wind resistance and seismic bearing capacity of the bridge. This study investigated the influence of the variations of bridge member parameters on the dynamic characteristics of the bridge and then improved the dynamic characteristics of the bridge. To provide the necessary experimental theory for the research work of the long-span dual-purpose highway-rail double-tower cable-stayed bridges, this paper takes the world’s longest span of the dual-purpose highway-rail double-tower cable-stayed bridge as the background, using the finite element analysis software Midas Civil 2022 v1.2 to establish a three-dimensional model of the whole bridge by changing the steel truss beam stiffness, cable stiffness, pylon stiffness, and auxiliary pier position, as well as study the influence of parameter changes on the dynamic characteristics of the bridge. The results show that the dynamic characteristics of the bridge can be enhanced by increasing the stiffness of the steel truss beam, the cable, and the tower. The stiffness of the steel truss beam mainly affects the transverse bending stiffness and flexural coupling stiffness of the bridge. The influence of cable stiffness is weak. The tower stiffness can comprehensively affect the flexural stiffness and torsional stiffness of the bridge. The position of auxiliary piers should be determined comprehensively according to the site conditions. In practical engineering, the stiffness of components can be enhanced according to the weak links of bridges to improve the dynamic characteristics of bridges and save costs.

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