Stability Analysis Of Long-span Concrete-filled Steel Tube Arch Bridge

Because of high bearing capacity, good anti-seismic behavior, convenience of high capacity, good economic benefit, steel tube-confined concrete arch bridge developed quickly in recent years. The stability problem becomes one of the important factors that restricting it's development as it's span increases. So it's necessary to analyze the stability of steel tube-confined concrete arch bridge.Steel tube-confined concrete arch bridge's development history, application and current research situation was introduced firstly in this paper. Based on structural nonlinear finite element theory and method, we obtained the criterion and mode of stability. Stability problems are generally divided into two types. The first type is to evaluate the eigenvalue which is easy to be calculated. The second type is the equilibrium path of extreme point types which is caused by nonlinear factors. The instability of most arch bridge in many projects belongs to the second type. Combining with the project examples, we analyzed the influence of nonlinear factors for instability of arch bridge with Midas/Civil, concluding linear elastic analysis and geometric nonlinear analysis. In the elastic analysis, we analyzed the whole bridge stability of all the condition after bridge operation. And we analyzed the factors that may influence stability such as the bridge live load, temperature lift, wind load and bearing subsidence etc, then considered geometry nonlinear stability is analyzed of the whole bridge. This paper discussed some factors of the structure design may influence the stability of CFST arch bridge, and summarize the rule of these factors on the stability of arch bridge.This paper rely on the engineering example, for CFST arch bridge in the stability of the bridge, after using finite element software calculation and analysis, the conclusion of the bridge to provide theoretical suggest similar.