Mechanics Analysis Of Rotation Construction Of Large Eccentric Flat Bending Steel Box Girder Bridge

Relying on the advantages of short on-site switching time,bridge switching construction can effectively avoid the cross-impact on the ongoing projects.It has been applied more and more in the eonstruction of urban roads,waterways and railways in China.In addition,steel box girders are often used in the construction of long-span bridges and small radius curved bridges with eccentricity due to their light weight and large stiffhess.Based on the engineering background of the fifth large curvature steel box girder rotation construction of H ramp bridge in SJ1 contract section of Shenzhen Section ? of Guangzhou-Shenzhen Riverside Expressway,this paper studies the mechanical problems such as the lateral eccentricity,force and deformation of the horizontal curved steel box girder bridge constructed with eccentric rotation.Firstly,the paper introduces the background and value of the theoretical research on Swivel Construction technology,the development status and theoretical research results of Swivel Construction at home and abroad,and the research purpose and main research contents of this paper in view of the large eccentricity problems existing in the relying projects.Secondly,based on ANSYS finite element software and theoretical formula deduction,two methods are used to study the transverse eccentricity of the main body of a variable cross-section flat-curved steel box girder bridge.Comparing the computerized and manual results,the main factors affecting the transverse eccentricity of the curved steel box girder are obtained.Thirdly,the deflection,global and local stress distribution and the influence of curvature radius on the construction of the swivel bridge in the maximum cantilever state are simulated and analyzed,and the influence of the curve radius on the deflection and stress of the same size steel box girder is obtained.Subsequently,under the action of eccentric load,friction force and traction force,the deflection,deformation and stress distribution of concrete structure and rotating spherical hinges in the rotating system are studied,and the effects of transverse eccentricity and total mass of the rotating main bridge on the rotating system are discussed in detail.Finally,the finite element software is used to simulate the closure stage of side span after turning the main body to the design route and the closure-completion stage of middle span under the second-stage loads such as residual deck pavement.The deformation and stress state under the dead load at each construction stage are obtained,and the variation law of deflection and stress at the same position before and after the two closures is discussed.At the end of this paper,the research content of this paper is summarized,and combined with the problems ignored in the research process,the prospects for the research on key technology of swivel construction are put forward.