Research On Construction Control Of Long-span CFST Arch Bridges

Concrete-filled steel tube arch bridges are favored by engineering circles because of their superior performance and simple and magnificent appearance.Similar to the reasonable completion state and construction state of the cable-stayed bridge,the determination of the reasonable state of the concrete-filled steel tube arch bridge is also the focus of the design and construction units.This article takes an engineering example as the starting point.First,it introduces the development and research status of concrete-filled steel tube arch bridges at home and abroad;secondly,it introduces the construction control methods of concrete-filled steel tube arch bridges.Finally,it is determined by the calculation of a falling frame of the concrete-filled steel tube arch bridge and the construction process simulation.The reasonable completion and construction status of the concrete-filled steel tube arch bridge are discussed.The main work of this paper is as follows:1.Explains the different methods of determining reasonable arch axis,and explains the applicable conditions and scope of each method of arch axis determination.On this basis,the pre-camber of the concrete-filled steel tube arch bridge is described.The actual calculation results show the characteristics and curve distribution of different pre-camber calculation methods,and indicate that the pre-camber setting of large-span steel tube concrete arch bridges is relatively The commonly used method is the thrust influence line method;2.Modeling analysis of the concrete-filled steel tube arch bridge,and studying the internal force distribution of the one-time falling frame of the concrete-filled steel tube arch bridge.This state is the reasonable arching state of this article;3.Based on the reasonable bridge status,the appropriate cable force is determined through the simulation of the construction process,so that the completed state of the steel tube concrete arch bridge formed by the cable-stayed buckle construction is between the bridge status and the proposed reasonable bridge status The difference between is as small as possible;4.Calculate several different line shapes through reasonable construction conditions,and elaborate on the common points and differences between the manufacturing line shape,the ideal bare arch line shape,the installation line shape and the calculated bare arch line shape in more detail;5.Explore the influence of cable removal conditions on the line shape and stress state of the main arch ring after arching,and vividly show the effect of cable removal on the structure through detailed analysis of the cable force on other cables at each step and the stress change of the concerned section.The impact is small.6.Investigate the process of concrete pouring in the main arch ring,and calculate the displacement,deformation and force of the main arch ring for each pair of steel pipes poured through simulation calculations.And by calculating the stability coefficients of different construction stages,to show the changes in the stability of the structure during the concrete pouring process in the pipe;7.Through the finite element simulation calculation,calculate the pre-lift value and pre-deflection amount of the column on the arch,and on this basis,it is shown that it is very necessary to take proper control of the lifting process of the column on the arch.