The Research On The Space Stress Performance Of A Single Cable Plane Cable-stayed Bridge With Ultra Wide Section

At present,the research object of shear lag effect of box girder is mostly single box single room section with single load.For the complex section,the research on shear lag of space loaded main girder,especially the single cable plane cable-stayed bridge steel box girder is relatively lacking.At the same time,single cable plane cable-stayed bridges only arrange cables in the central axis of the bridge.In order to ensure enough torsion resistance of the box girder,the closed wide box girder with large rigidity is often chosen as the main beam section,but the torsional distortion effect of box girder section is rather complicated when subjected to partial load.Therefore,it is necessary to make a thorough study of the two.In this paper,a detailed summary of the domestic and foreign related research status of box girder stress and methods,combined with the Guangdong city of Qingyuan Province River four bridge engineering background,studied on force of cable-stayed bridge with super wide steel box girder of single cable space,mainly for the following aspects of the work:The cable-stayed bridge and cable-stayed bridge with single cable development,introduces the status of domestic and foreign research on shear lag and torsion effect,put forward key technical problems of Beijiang River Bridge,the shear lag effect of box girder and torsion effect of the theoretical background of research methods,and compared the shear lag different analysis methods.In view of the unique space stress condition of single cable plane cable-stayed bridge,considering the structural stability during the completion stage,the shear lag and torsion effects of the main girder section of the four bridges under the North Bridge are analyzed by using the finite-element simulation method.The results show that the shear lag effect of roof and floor girder with different cross-section differ from the symmetric load increases in the range of top plate web shear lag effect changes obviously;the same load,span side girder torsion and distortion effect than the side span,with partial load increase,the top and bottom section of main girder torsion and distortion effect enhancement.Structure optimization of steel box girder in the design process based on using parameter analysis method,studies the design parameters of the diaphragm thickness,diaphragm spacing,thickness of roof and floor thickness on the influence of shear lag,the bottom section of the top torsion effect of steel box girder bridge phase control.The results show that the variation of the diaphragm thickness and spacing has a significant effect on the shear lag effect of the roof and floor of the main girder.The thickness of the top and bottom plate has a significant effect on the torsion distortion effect of the roof and floor,but the variation of diaphragm spacing has little effect on the shear lag effect.Considering the spatial deformation problem of the main girder of single cable plane cable-stayed bridge during lifting and completion stage,it provides data reference for actual construction,and analyzes the influence of different lifting points combination and the different lateral layout forms of the live load during the construction stage on the spatial deformation effect of the main girder.The results show that the vertical relative displacement of the steel box girder is closely related to the location of the lifting point during the lifting stage,and the vertical deformation of the main girder under the positive and partial load is obviously different from that during the completion stage.