Study On Reasonable Construction State Determination Method Of Hoisting Process For Long Span Concrete Filled Steel Tubular Arch Bridge

The concrete-filled steel tubular structure improves the compressive strength and ductility of the concrete which not only increases the stability of the steel pipe wall,but also combines the steel and the concrete,and it is widely used in the bridge engineering field.In recent years,the concrete-filled steel tubular arch bridge has become more and more large,the construction method of cable erection inclined cable-stayed were adopted in most of the large-span concrete-filled steel tubular arch bridges.The method of determination the reasonable construction state of the concrete-filled steel tube arch bridge has become a popular Research topics.Daxiao Jin super bridge is taken(the main span of 450m over the concrete-filled steel variable cross-section truss arch bridge)as the engineering background.In this paper,the bridge construction of the large-span concrete-filled steel tube(CFST)arch bridge is carried out with the following work.(1)This paper introduces the development of concrete-filled steel tubular arch bridge and the calculation theory of concrete-filled steel tubular arch bridge,including the selection of reasonable arch axis and the adjustment method,the theory of shrinkage and creep,and the finite element theory,the influence matrix principle and the principle of non-stress cable length method.The method of calculating the cable tension in the state of reasonable construction is reviewed.(2)The finite element calculation software BDCMS is used to establish the calculation model of the whole process of the sinking of the flywheel of the large and small bridge to get the internal force,the stress and the displacement state of the bridge of the large and small bridge Finally,SThe state of empty steel pipe installed is taken as the goal state of cantilever construction(3)The finite element calculation software BDCMS is used to establish the calculation model from the empty steel pipe maximum cantilever state of Daxiao Jin bridge to move supporting cable.The state of empty steel pipe installed is taken as the reasonable cantilever construction state,and the effective state of the empty steel pipe is obtained by using the influence matrix method to obtain the cable force of each cable in the maximum cantilever state of the empty steel pipe.(4)The finite element calculation software BDCMS was used to establish the calculation model of the whole process of the construction of the Daxiao Jin bridge.The principle is used that the cable length of the maximum cantilever state of each cable under the stress-free cable length is equal to the cable at the end of the tension-free cable length(in the process of hanging each cable were only a tension),to determine the hanging construction of the cable in the initial tension,and cantilever-splicing construction of all the reasonable construction state.Through the above methods,we can get the reasonable finished dead state of the large span concrete-filled steel tubular arch bridge during the cantilever-splicing construction,which avoids the repeated recoil and improves the efficiency,and provides some reference for the design and construction of the long-span concrete-filled steel tubular arch bridge.