Influence Of Diaphragm On The Mechanical Behavior Of Continuous Box Girder Bridge With Large Span Variable Cross Section Corrugated Steel Web

Corrugated steel web box girder with its superior performance has been widely concerned about the world,at present,China is also in the field of in-depth research.Because the thickness of corrugated steel webs is thin,the flexural stiffness in the face is reduced,and the frame effect of restricting section deformation is reduced.At the same time,the longitudinal stiffness of the corrugated steel plate is also small,so the torsion and distortion effect of the structure is enhanced under eccentric load.In engineering,it is usually reasonable to set the diaphragm to limit distortion deformation and improve torsional stiffness.In order to study the torsion and distortion effect of the box girder bridge under the eccentric load of different diaphragm.Based on the engineering background of Nanchang Toyama-Jiangxi Jinshajiang Bridge,the finite element software Ansys is used to establish the numerical model,and the working condition model of different diaphragm is established by changing the number,position and thickness of the diaphragm.The load decomposition method is applied to the model of each working condition by symmetrical load,rigid torsion load and distortion load,and the deformation and stress under different loads are analyzed,and the following conclusions are obtained:(1)The distortion effect of corrugated steel webs box girder under eccentric load can be reduced greatly by setting a small number of transverse partitions,and the torsional stiffness is also obviously improved.(2)It is more advantageous to resist torsion and distortion effect when the box girder with variable cross-section is arranged by equal spacing.(3)Increasing the thickness of the diaphragm can reduce the torsion and distortion effect of the box girder of the corrugated steel webs slightly,but the symmetrical bending positive stress,torsion warping positive stress and eccentric load positive stress of the diaphragm are obviously increased with the thickness of the diaphragm.Considering that,the thickness of diaphragm should choose the smaller value under the precondition of satisfying the construction requirement.