Study On Nonlinear Stabilities Of The Long Span Bridge For High Speed Railways

With the vigorous development of modern high-speed railway the standard of performance of arch bridge is growing higher and higher, of which the form of the destruction is investigated as an essential subject, that is, arch strength failure and instability failure. The lateral stiffness of large span arch is relative poor, of which stability problems often need to focus on especially. Stability problem includes linear elastic stability and nonlinear stability. The process of loading experiment of arch bridge involves a complex nonlinear problem. Additionally, nonlinear problems classify geometric and material nonlinearity. Here a half-through high-speed rail arch bridge with large span is employed as object. The bridge’s safety factors in both linear and nonlinear states have been analyzed, and factors influencing on the stability of object have been discussed.Firstly, introduction on the recent development of CFST arch bridges in China and challenges is presented in the paper. Then the theory of stability of arch bridge is studied, stability safety factors affecting the arch roll are analyzed theoretically. Furthermore the finite element method for arch bridge is researched as well, leading to common phenomena in arch analysis--material nonlinear, large displacement with small strain and large displacement with large strain problem. Finally, basic solutions of nonlinear problems are investigated.Finally,the ANSYS model of Yachihe Bridge is created based on the theories before.The safety stability calculations are got under the conditions of elastic linearity,geometrical nonlinearity and material nonlinearity.Stability coefficient of arch bridge is more than that of Considering the geometrical nonlinearity, but the difference is not so large.But,Stability coefficient of arch bridge is almost two times than that of Considering the geometrical nonlinearity and material nonlinearity.There are some factors that affecting the the stability of arch bridges including non directional force,directional force,,brace,arch rib sloping angles,materials and so on.There is huge effect of Transverse Brace on Stability of Arch Bridges With the increase of arch rib obliquity,the linear stability coefficient will increase.The influence of stability of arch bridges is different according to the different types of arch bridges on the effect of non directional force and directional force.