Study Of The Stability Of Half-Through Cfst Arch Bridge

More than ten years, concrete-filled steel tubular arch bridge have developed rapidly, but compared with the engineering practice, the theoretical research of the CFST arch bridge is relatively backward. Along with the increase of the span and the decrease of the width-span ratio, the stability of CFST arch bridge is increasingly important. Therefore, research on it has important theoretical significance and engineering value.Stability problems are usually divided into two kinds:the first one is branch point instability which comes down to the eigenvalue problem, the second one is extreme point instability considering nonlinearity. Generally, the stability of engineering problems belong to extreme point instability.Firstly, the paper introduced the theories of the linear and nonlinear stability analysis and its solution. On the basis, using the FEA software ANSYS,the paper analyzes the linear elasticity, geometric nonlinearity and double nonlinearity of a CFST arch bridge with a span for204m during the construction phase. The analysis results show that:the result of the linear elastic analysis is not safe for design and construction. The stability analysis in the construction stage of a CFST arch bridge must consider the double nonlinear effect. Finally, the paper discusses the influences caused by the setting of wind cable, pouring sequences of the core concrete, the number and layout of cross braces and initial geometric imperfection, and put forward the reasonable and feasible advice. This calculated results and conclusions have some reference value for design and construction of CFST arch bridges.