Abstract:To address the complex structural force problems of the special-shaped arch bridges in the strong earthquake zone, by selecting the actual project as the research object, three structural systems of multi-span continuous arch, multi-span rigid-frame continuous arch, and rigid-frame and arch-girder combination are designed. A refined three-dimensional finite element model is established using finite element software to systematically analyze and compare the internal force distribution of each structural system under dead load, live load, temperature change and earthquake load. By comparing the force states of key sections such as arch ribs and girders in different structural systems, the influence of structural type on the force performance of special-shaped arch bridges is revealed. The results show that without seismic isolation and reduction measures, the multi-span continuous arch and multi-span rigid-frame continuous arch structural systems present better response performance under static and seismic loads. In strong earthquake zones, the effect of seismic load is much greater than that of static loads, so seismic isolation and reduction measures must be adopted to ensure the reasonable forces of structures. Seismic performance is the key factor determining the structural system. In the rigid-frame and arch-girder composite system, the arch and beam are separated. Adding seismic isolation bearings can effectively improve the seismic performance of multi-span special-shaped arch bridges in strong earthquake zones. The analysis shows that the seismic internal force response is greatly reduced with excellent seismic performance, so this system can be recommended for strong earthquake zones.
