The Study On The Buckling In Plane Of Arch Structure Of Concrete Filled Steel Tube By Finite Element Method

With the development of national economics, more and more wide-span structure are built. Arch-Structure applied in many wide-span building and bridges structures, which uses less materials, has less self-weight, may spread much more span and has graceful appearance. Concrete filled steel tube (CFST) , which is used conveniently in construction and has high carrying capacity and economic benefit, is a good composite material. Arch-Structure of CFST will be tend to applied in China for the good stress performance of Arch-Structure and the appliance of new materials. Because of the development of new structural form and the appliance of high carrying capacity materials, the structure is to be more lighter and thin wall. So it is necessary to study the buckling performance of structure. In this paper, a finite element program is designed to analyze the stability of arch of CFST by the MATLAB computer language. Based the practical situation of the program, the arch method is introduced to solve the nonlinear finite element equation set. Moreover the arch constraint equation is also modified, which it is explicit in physical meaning and simple in form so that it is easy to design program. The numerical examples show that the arch method, U.L method and MATLAB computer language are the accurate method and efficient tool on the stability analysis of structure. The finite element model of parabola arch is built by ANSYS finite element software in order to testify the program accurate and gain some conclusions in construction. The result, which gained by varying the ratio of rise to span (f/L), steel ratio (a ) and concrete strength, shows that the global stability of arch bridge of CFST can be improved by adopting the reasonable ratio of rise to span (f/L) and high strength concrete and so on.In conclusion, the buckling analysis for Arch-Structure of CFST is of great significance in both theory and practice.