Bucking Anslysis Of Variable Cross-section Corrugated Web Steel Box-concrete Composite Continuous Girder Bridge

Corrugated web steel box-concrete composite girder is a new type of steel-concrete composite structure.Replacing the concrete bottom plate of the traditional corrugated steel web-concrete composite box girder with steel bottom plate,which not only reduces the weight of the bridge superstructure,but also improves the bearing capacity of the bridge,and because of its special knot form,the material properties of steel and conctrte can be fully utilized.So it has been gradually used in highway bridges.In order to study the shear resistance of variable cross-section corrugated web steel box-concrete composite continuous girder.This paper takes a 5-span variable cross-section corrugated web steel box-concrete composite continuous girder as the research background,and uses theoretical analysis combined with ANSYS numerical simulation methods.Study and analyze the web buckling stability and ultimate bearing capacity of this type of bridge.The main research contents are as follows:(1)According to the essential principle of solving the critical value of buckling and the theory of small deflection,specific equilibrium differential equations of isotropic plates and orthotropic plates during bifurcation buckling are given;The theoretical formulas of elastic local buckling strength and global buckling strength of corrugated steel webs were derived using Rayleigh-Ritz method and Galerkin method,and compare and analyze the calculated value of this formula with the ANSYS finite element value and literature value.The results show that the calculated value of the derivation formula in this paper is in good agreement with the literature value and the finite element value,which verifies the correctness of the derivation formula in this paper.(2)The ANSYS finite element method was used to study the buckling sensitivity of variable cross-section corrugated steel web with different corrugated types,different web thicknesses and the variation of beam height,and to summarize the influence of various parameters on buckling stability.(3)Based on the analysis of buckling eigenvalues of variable cross-section corrugated steel webs with different corrugation types,different web thicknesses and different girder height variations,the initial defect of the wave size,material nonlinearity and geometric nonlinearity are taken into account.The whole process of the buckling of the variable cross-sections corrugated steel web of different structural parameters was tracked and analyzed by using the finite element analysis software ANSYS.The change trend of ultimate capacity and behavior after buckling of corrugated steel webs with different structural parameters are summarized.(4)Combined with the concrete 5-span variable cross-section corrugated web steel box-concrete composite continuous girder.The elastic buckling strength,non-elastic buckling strength and shear resistance of the corrugated steel web of each typical segment are calculated theoretically.And based on the ANSYS finite element,the corrugated steel webs of the relevant segments are selected for buckling eigenvalue analysis and nonlinear analysis,and the theoretical calculation results are reviewed.The results show that: The finite element value of the corrugated steel web of each segment is consistent with the theoretically calculated value,and the elastic buckling strength is much higher than the yield strength.The shear strength of the corrugated steel web is controlled by the yield strength.