关键词: 组合体系, 稳定性, 自锚式悬索桥, 上承式拱桥, 极限承载力, 有限元分析

Abstract: The self-anchored arch-suspension bridge is characterized by innovative structure and beautiful shape. It has great engineering significance to research on the stability of this structure that has never been built. Firstly, the dead load state and the transfer mechanism of live load were introduced in detail. Secondly, based on a self-anchored arch-suspension bridge scheme with a main span of 406 m, the universal finite element software ANSYS was adopted to study the linear elastic stability, geometrically nonlinear stability and double-nonlinear ultimate load-bearing capacity under six load cases. Also, the influence of the initial imperfection on the structure was discussed. Finally, for comparison, the deck arch bridge with the same span was studied to find out the differences of the stability between these two structures. The results show that the first-order linear elastic instability modes are both lateral flexure of the junction at mid-span for these two structures. And the load applied on the structure has a certain influence on the overall stability and failure mode. In order to analyze the ultimate load-bearing capacity accurately, the geometric and material nonlinearities need to be taken into account. At the same time, the out-of-plane initial imperfection has little influence on the ultimate load-bearing capacity for the self-anchored arch-suspension bridge.

Key words: combined system, stability, self-anchored suspension bridge, deck arch bridge, ultimate load-bearing capacity, finite element analysis