| Because the concrete-filled steel tube arch bridge has a light weight,strength and strong resistance to deformation advantages, Better adapted to many requests which the modern bridge construction must achieve,these are saving the material,the erection weight well to be light,the construction was simple,bearing capacity big and so on. In recent years it has been the rapid development and wide application. The concrete-filled steel tube" Fly-Bird-Type" arch bridges as one of the very important characteristics of bridge,by its excellent esthetics image and steel pipe concretes material strong superiority and receives bridge engineers'favor unceasingly. However, it belongs to the new bridge after all, various aspects theory and the technology are not consummate very maturely. Many problems to be studied, then carries on the analysis, the discussion, the research to its stability appears has the necessity very much.This paper discusses the steel tube concretes mechanical properties, he arched bridge stable question computation theory as well as the structure of nonlinear finite element method based on the basic theory, take the span 55+240+55m Jianghan five bridges as the project backgrounds, to flies the concrete-filled steel tube " Fly-Bird-Type" arch bridges stability to carry on the modelling analysis.Establish separately using MIDAS and the ANSYS two kind of large-scale general finite element softwares fly the swallow type steel pipe concretes arched bridge's structure computation model, And carries on the numerical simulation analysis of bridge construction process and its stages of working conditions into the linear elastic and elastic-plastic stability. The first-class stable safety coefficient, unstable mode and the second-class stablesafety coefficient on various loads are obtained. The analysis result shows that the stability factor of the bridge is bigger in the linear and elastic condition, while the value of the stability factor only decreased a little when taking into account geometrical nonlinearity. But when the material nonlinearity is considered, the value of the factor become a greater decline. It also shows that the instability of this archbridge almost happens in the plastic area, and stress of theis bigger than the high-point of the elastic stress. The stability factor will be very bigger if the linear method is used in analyzing the stability of the bridge. So the ultimate loading is exact only when we consider the geometrical nonlinearity and material nonlinearity.Finally,to affected stable primary factor to launch the discussion. The distinction computation analyzed, these are arch axis coefficient arrow cross ratio,extends the cross ratio,rib stiffness,suspension bar rigidity,the effect of non-orientedly conservative loadings of the hanger, as well as the wind supports quantity, form, position and rigidity and so on each kind of factor to arched bridge stable influence. Studies under the different value condition the structure stability of the different values of the impact factors of the reasonable range of values or in the form.
|
PDF Full Text Request