Research On Unitary Stability Of Long Span CFST Bow String Arch Bridges

Because of its merits of high carrying capacity, upstanding plasticity and toughness, construction convenience, better economic effect and better foundation adaptability, the concrete filled steel tube bow string arch bridge is one of the bridge structures that have broad prospects for development. But this kind of bridge 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 bow string arch bridge's development, so it needs bridge theory researchers to study mechanics performances and the design method of this kind of new bridge thoroughly and comprehensively in order that it can promote our country's transportation development vigorously. The stability of a long span CFST bow string arch bridge is studied in this paper. As a long span CFST bow string arch bridge, it has vital significance that we study and obtain correlative conclusions.A three dimensional finite element model of a CFST bow string arch bridge is built by using the analysis software ANSYS8.0, and is also studied, and some coefficients of stability of different state after the construction are found. On the basis, the influence of different factors such as the shape and the rigidity of the wind bracings, rise-span ratio, the rigidity of bridge deck system, the rigidity of the arch ribs is discussed.On the basis of summarizing the existing basic analysis theory of CFST and analysis theory of stability of arch bridge, two kinds of three dimensional finite element model of a long span CFST bow string arch bridge are built, one is a model that takes into account the bridge deck system and hangers, the other is a model that does not take into account the bridge deck system and hangers. The stabilities of the two kinds of model are calculated. This paper analyzes the bridge's stability in different situation, and discusses several factors that affect the stability of the CFST bow string arch bridges. Then some conclusions are drawn and numerical values of the factors are brought forward. It is useful for the guidance and the reference to the readers who engage in bridge construction.