Study On Spatial Mechanical Properties Of Single-box Multi-cell Curved Box Girder With Corrugated Steel Webs

Based on the basic scientific research business fee funded project(300102288110)of Chang ’an University Central University,this paper studies the spatial mechanical properties of single-box multi-cell curved steel web box girder bridge.The structure of single-box multi-cell box girder bridge with corrugated steel webs is complex and has many influencing factors.Under the action of eccentric load,this paper divides it into shear lag mode,torsion mode and local vertical distortion mode.It mainly studies the torsion effect of single box single room asymmetric box girder bridge and the local vertical distortion effect of corrugated steel web box girder bridge.The main research results are as follows:(1)Based on the plate beam frame method,considering the displacement of four corner points,the distortion calculation method of box girder with unequal web thickness is proposed.The distortion differential equation of single-box single-cell asymmetric box girder is derived,and the initial parameter method is used to solve the equation.(2)Based on the theory of thin-walled box girder,ignoring the axial stiffness of corrugated steel webs,the distortion differential equation of asymmetric corrugated steel web box girder is derived,and the calculation formula of distortion warping stress is solved.Based on the second theory of Umanski,the calculation formula of rigid torsional stress of box girder with asymmetric corrugated steel webs is derived by assuming that the surrounding section is not deformed.The ANSYS model of box girder with unilateral cantilever plate corrugated steel webs is established,and the distortion and rigid torsion warping normal stress are obtained.The distortion and rigid torsion warping normal stress of box girder with non-cantilever corrugated steel webs are compared and analyzed.The distortion coefficient,rigid torsion coefficient,cantilever distortion influence coefficient and cantilever rigid torsion influence coefficient are introduced,and the practical calculation formula of torsion stress of box girder bridge with unilateral cantilever plate corrugated steel webs is obtained by fitting.(3)The box girder side chamber under the local vertical distortion mode is decomposed into the torque effect caused by the vertical antisymmetric external load and the torque effect caused by the horizontal antisymmetric constraint reaction force.Based on the assumption that the rotation angle of corrugated steel webs is zero,a local vertical distortion performance analysis method for single-box multi-cell box girder with corrugated steel webs is proposed.(4)By establishing the ANSYS model of single-box multi-cell curved box girder with corrugated steel webs,the influence of the central angle of the box girder,the number of chambers,the aspect ratio,the top plate,the bottom plate,the web and the diaphragm on the torsional performance of the single-box multi-cell curved box girder with corrugated steel webs under external eccentric load is analyzed,and the variation law of various structural parameters on the section stress is clarified.