Theoretic Analysis Of Arch Rib Steel Tube Heat-Bending Treatment In Arch-Bridge Of CFST

In recent 10 years, more and more Arch-Bridges of CFST have been built in our country. Focusing on its quality engineers deeply pay attention to the manufacturing craft of arch rib. So far, many kinds of manufacturing crafts of arch rib steel tube have been developed. among them the heat-bending treatment craft is widly applied at most. At present, the heat-bending treatment of steel tube is generally conducted according to experience because theoretic analysis can get only numerical solution or finite element solution due to complicated temperature distribution and distortion in the process of the heat-bending treatment. Thus, it is difficult for us to control the distortion error of steel tube in the heat -bending treatment. This thesis is aimed at analyzing the problems in the process of the heat-bending treatment in the following aspects.1. Partial buckling always happens during the heat-bending treatment of steel tube. This thesis is aimed at getting criterion of partial buckling of steel tube through finite element analysis of buckling full-process. Furthermore the loading approach is built up to make sure that partial buckling no more happens by controlling section moment not more than buckling moment.2. The distortion of steel tube during the heat-bending treatment is a troublesome problem in the theoretic analysis. This thesis achieves an equation of section moment and bending curvature and deflection curve equation during the heat-bending treatment of steel tube by means of numerical integral and regression analysis.3. The computation of springback during the heat-bending treatment of steel tube is important to the manufacturing of model. Combining with classic elastic-plastic bending springback theory, this thesis develops the computing formula of springback after being unload and cooledon the steel tube.It can be seen that the result of theoretic computing is consistent with the one of finite element method through engineering examples. The calculating formulae in this thesis are simple and convenient for application. The achievement of this thesis is worthy of conducting the heat -bending treatment of steel tube. Besides, it can instruct the creation of models and improve creating efficiency and quality of the arch rib steel tube.