| Because of its merits of high carrying capacity, upstanding plasticity and toughness, construction convenience, better economic effect and better fire performance, the concrete filled steel tube bow string arch bridge is one of the bridge structures that have broad prospects for development. But the structure of the bridge is complex, there are many influence factors for structural mechanics performances, the stability, the natural vibration characteristics. But this kind of bridges has a short development period in China, and many aspects are studied insufficiently. The situation will bring the adverse effect to the concrete filled steel tube string arch bridge's development.The paper study a large span CFST arch bridge with the universal FEM software ANSYS. Different 3-D finite element models are built according to different leaning angles. Firstly, the static force, stability, dynamic characteristics of the bridge with leaning angle is 0 in the paper are analyzed. Secondly, the structural displacement and internal force under self loud action, instable modality and stable coefficient of different state, the natural vibration frequencies and modes are discussed. The results indicated that the problem of structural lateral stability is highlighted. Then, structural mechanics performances under different leaning angles are made the same analysis, and the comparative analysis from the other kinds of models has been carried out that the optimal value of leaning angle is 10°.Besides, the paper builds element model with leaning angle is 10°, and the analysis of structure parameters, such as thickness of steel tube, steel tube diameter, concrete elasticity coefficient and the form of cross-brace, the disposal of cross-brace, suspender and supporting condition, influence on structure stability and dynamic characteristic property, then some conclusions are drawn and numerical values of the factors are brought forward. The result is usable for the optimal design of this same kind of bridge. |
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