A Finite Element Analysis On The Stress And The Stress Concentration Of Tubular Joint In Concrete-filled Steel Arch Bridge

Recently, the concrete-filled steel tubular structure is adopted widely in bridgeengineering, which is high of load-carry capacity, good at plasticity and malleability,easy to execute and construct, excellent in fire resistance and economy. For thisreason, this kind of combined material is applied to arched bridge that is mainlyoppressed. In the joints on this type of arched bridges, the forces are to be spread tothe brace through the chord directly. Because the axial rigidity of the brace is muchbigger than the radial rigidity of the chord, the border becomes the weakest part of thewhole structure. The reasonable design of this type of joint has attached theresearchers'attention all over the world.As the part of"The key techniques of thedesign, construction and maintenance of concrete-filled steel tubular arch bridges"supported by the Science and Technology Item of Construction of the WestwardTraffic, The main contents are detailed as following:(1) The feature and the development situation in arch bridge of the steel pipeconcrete are briefly introduced. the item pay attention to designing the concrete-filledsteel tubular arch bridge has put forward, and there are the introduction of the SaintVenant's principle and the application in the concrete-filled steel tubular structure.(2)According to a four-tubes of truss concrete-filled steel tubular arch bridge -The maocao street bridge, in Yiyang, Hunan province, China, three typical nodes inthis project, that is, DTY, XYT and DTDY tubular joints, are chosen as the objects tostudy. With the help of ANSYS, the entity models of the concrete-filled steel tubularare set up to analyze, and then static characteristics are carefully compared. Finally,the regulars of their stress variation are particularly investigated.(3) the analysis and calculation on variation of stress concentrate factor for bothconcrete-filled steel tubular and hollow steel tubular DTY joints, XYT joints, DTDYjoints under the axial strength or axial and bending loadings together function in bracealong with the variation of diameter of braces and the included angle of braces andchords the have carried out. The results show that the concrete-filled steel nodes aremore obvious than the empty steel tube nodes on stress concentrate phenomenon andas well as nodes under the function of axial strength than axial and bending loadingstogether function in brace.