The Stability Analysis For The Lift-basket Concrete Filled Steel Tubular (CFST) Arch Bridge

The lift-basket concrete filled steel tubular(CFST) arch bridge improve the lateral stability by sloping the arch rib , the CFST truss rib consisting of longitudinal CFST elements, hollow steel tubular diagonal lacing or steel plate web, it has higher section efficiency than single and dumbbell shape rib, and it is often widely used in the designs of CFST areh bridge with small ratio of the width to the span. So the research of the stability and supporting capacity of the lift-basket concrete filled steel tubular(CFST) arch bridges have great engineering value and theory significance.In this paper, the development and current situation for the lift-basket concrete filled steel tubular(CFST) arch bridge have been brief introducted. the research results of domestic and overseas scholars on stability and supporting capacity of the lift-basket concrete filled steel tubular (CFST) arch bridge are roundly summarized and the theory of finite element method to analyze the stability and supporting capacity of the lift-basket concrete filled steel tubular(CFST) arch bridge are also introduced in detail. From the work done by now,we know that: in aspect of stbaility analysis,the first kind of stability analysis is often calculated instead of the second kind of stability analysis and the geometry nonlinear analysis is often ignored more than the material nonlinearity analysis. In addition, model experiment is carried infrequently which leads to the short of cognition of stress of CFST arch bridge,especially the kind with truss lift-basket arches;it is needed to make sure the influence of section design on the stability of CSFT arch bridge with truss lift-basket arches.Finite element model for Taiping lake Bridge was established by useing of the common software ANSYS , the instability mode and the relevant stable safety coefficient also have been acquired by the analysis for the lift-basket concrete filled steel tubular (CFST) arch bridge on the working condition and also discussed the global stability for Taiping lake Bridge on the working condition. In addition,this paper also discussed the stability of influence for the lift-basket concrete filled steel tubular(CFST) arch bridge on the working condition as physics,geometric characteristics indicator such as arch rib single pipe section area, wind braces section area, wind braces decorate form, arch section height, arch rib angle and so on.(1) The arch of Taiping Lake Bridge is used of truss section. Because of the larger span and weak stiffness of plane, the Plane buckling instability is the main form of instability. The basket arch structure can enhance the stability of the plane.(2) With the changing of wind braces steel tube stiffness , the coefficient of stibilization of The lift-basket arch bridge changes more apparently. Through the parameter analysis and the appropriate wind braces steel wall thickness selecting can significantly improve the stability of arch bridge structure surface. In addition the variations of wind braces parameters has bigger role on the stability of the lift-basket arch bridge .(3) Because of the influence of initial imperfection, the elastic stability analysis can not calculate the stability effectively. But the ultimate capacity can consider the influence of initial imperfection. So, it can not consider the impact of initial imperfection bu using the elastic stability analysis.(4) Taiping Lake Bridge for the purposes of this article, when the inclination of is 10o, its lateral stability increased 17.95% and vertical bearing capacity reduced 2.17%. And when its inclination angle increased, the lateral stability increased limited and the capacity of vertical bearing reduced much. Therefore, for any Arch Bridge, it always has reasonable inclination angle for its own.