Study On Arch Rib Pre-arch Of Concrete Filled Steel Tube Arch Bridge

CFST(concrete filled steel tube) arch bridge which has property of high carrying capacity, fine plastic and aseismatic ability, has been used widely in construction in recent years. At present, however, the design of CFST arch bridge has been adopting design criterion based on concrete arch bridge, and the factual property of CFST cannot be reflected. Especially, when set pre-arch of arch axes as old design criterion, the arch bridge cannot be accurately estimated. There is an actual project, Nan-pu-hong Bridge in Ezhou city, Hubei province, which is CFST arch bridge with a span of 120 meters and a arched rise of 20 meters, and belongs to big span CFST arch bridge. A series of research and analysis on the problem of setting pre-arch of CFST arch bridge based on the project has been made with finite element method in this paper. The major achievements as follows:Firstly, the reasons on the setting of pre-arch of arch bridge, the factors considered in actual setting and the setting methods are systematically summed, and the pre-arch has been calculated based on the actual CFST arch bridge.Secondly, the analysis model of finite element method of CFST arch bridge is established in this paper by using ANSYS based on the actual project.Thirdly, in the course of establishing mathematics model, transforming on material and section of arch rib has been used so that the carrying property of actual structure can be possibly reflected by the section of arch rib in finite element method model.Fourthly, the maximum of deflection of actual CFST arch bridge with deadweight has been measured, and the static test for complement of actual CFST arch bridge has been made.Fifthly, the maximum of deflection, namely pre-arch of actual CFST arch bridge with deadweight and load of static test for complement has been simulated. The validity of the finite element method model has been proved by the fact that simulating result and testing value are very conform.Finally, the frequency and vibration of actual CFST arch bridge have been calculated with the method of finite element at the precondition of setting pre-arch and origin, and the conclusion has been attained that the effect of dynamic characteristics of CFST arch bridge is not obvious no matter whether the pre-arch has been set.The researching achievements are some significant and valuable to the setting and effect of pre-arch on arch bridge, especially on CFST arch bridge in practice in this paper.