Study On Construction Technology Of Eccentric Swivel Of Asymmetrical Steel Box Girder Bridge With Small Curve Radius

Across the Shijiazhuang Taiyuan railway,Shijiazhuang Heping Road Viaduct extension project WS ramp is completed by turning the box structure.The superstructure of the bridge is a(70+70)m variable height steel structure box girder rotating T structure.The substructure is a hollow pier with a rectangular section of 6.4 5m by the thickness of 1.25 m,and the connection system is rotated under the piers.In view of the eccentric rotating construction of the continuous steel box girder bridge with the radius of the small curve,the main work and achievements are as follows:(1)For the construction problems of the welding internal stress of the steel girder of the eccentric swivel of asymmetrical continuous steel box girder bridge with small curve radius and the difficulty in control the fabrication and installation precision of the steel girder.Through the detailed design and analysis of beam segment and plate unit division scheme,the method of dividing the beam segment and the principle of dividing the plate unit are summarized.(2)From the analysis of overall internal force and the local deformation,the influencing factors of the pre-camber of the main girder construction of the eccentric swivel of asymmetrical continuous steel box girder bridge with small curve radius are analyzed,and the problem of manufacture and hoisting of the main beams are solved.(3)According to the asymmetrical continuous steel box girder bridge with small curve radius,due to the effects of curvature,the horizontal eccentric torque is large and the plane line shape is not easy to control.Due to the large-span,the vertical deflection of curve bridge is larger than the same span straight line bridge,and vertical linear control is difficult.According to design requirements and actual situation at the construction site,we need make a study of the establishment of construction control system,the calculation of the hanging height of the main girder,the influence of the local deformation of the steel box girder on the linear shape of the main girder and the identification and prediction of the parameters in the construction.The problems of construction control of the eccentric swivel of asymmetrical continuous steel box girder bridge with small curve radius are solved.(4)Due to the material non-linearity and the construction factors,the stress distribution on the box girder section is not ideal;the internal force and displacement of the rotating girder are affected by the counterweight largely;the control of construction process is difficult.Study on the influence of structural parameters,such as radius of curvature,width-span ratio,aspect ratio,web thickness,number of stiffeners and spacing of diaphragm on the bearing capacity and deformation characteristics of curved steel box girder,should be done to solve the problem of the force performance of the eccentric swivel of asymmetrical continuous steel box girder bridge with small curve radius.