Study On Static Stability Of Longtanhe Bridge

The development of finite element model theoretical and finite element software, nonlinear analysis of stability problem is realized in the process of development of CFST arch bridge toward large span.This text discusses the stability of CFST arch bridge theoretically first. Two stability analysis methods are used: eigenvalue stability analysis and nonlinear stability analysis. Then, it takes Longtanhe CFST arch bridge of 208m span which has already set up as an example. Using the two analysis methods, by means of large and general finite element software ANSYS, establish three-dimensional finite element model of the bridge, arrange live load through analyzing bending moment influence line on typical section. Under several different load cases, stability is analyzed. Considering the material and geometric nonlinear property, carry out discussion on the stability problem during the finished bridge state. Also, the affect on stability of initial geometrical imperfections is considered. Stability safety factors are analyzed and compared under each method and load case, the results suggest that the dual nonlinearity must be considered in analyzing stability of CFST arch bridge under operation condition. A certain of initial imperfection is allowed in the range of requirement of stability. Analyze the stability of the bridge with different arch axis shape, the reasonable arch axis will be obtained by means of stability factors. The results suggest that the reasonable arch axis has been obtained by the real bridge.Finally, modifying parameters of the finite element model, by using of eigenvalue stability analysis.The effect of different factors such as wind bracing, the sloping angle of arch ribs,the stiffness of arch ribs and width-span ratio etc is discussed for whole stability of the bridge.