Study On Shear Behavior Of Composite Box Girder With Variable Height Corrugated Steel Webs

In this paper,the formulas for calculating shear stress of variable cross-section corrugated steel web girder bridges are deduced firstly.It can be seen from the formulas that the additional shear stress caused by bending moment and axial force should be taken into account in the calculation of shear stress of variable cross-section corrugated steel web girder bridges,which is quite different from the calculation method of shear stress in equal cross-section beams.Subsequently,an example model of corrugated steel webs with variable cross-section is established to study the shear behavior of corrugated steel webs.The results show that the shear stress calculation formula of corrugated steel webs with variable cross-section is close to the actual situation of the model analysis,while the result of calculating shear stress of corrugated steel webs with equal cross-section is quite different from that of corrugated steel webs with equal cross-section.It shows that the traditional formula for calculating shear stress of Secondly,the influence of bottom plate thickness and end inclination angle of corrugated steel webs with variable cross-section on shear strength is studied.It is found that the end inclination angle and bottom plate thickness of corrugated steel webs with variable cross-section can be increased appropriately to make the force more reasonable in the design of corrugated steel webs bridges with variable cross-section.Finally,the buckling stability of corrugated steel webs with variable cross-section is studied in this paper.The influence of beam section parameters(beam height and web thickness)on ultimate shear buckling capacity of corrugated steel webs is discussed.The buckling strength of steel webs decreases with the increase of cross-section beam height,but increases linearly with the increase of web thickness.Therefore,it is necessary to rationally design the beam height and web thickness of root section in practical engineering.Then,the influence of the angle between upper and lower flanges on shear buckling of corrugated steel webs with variable cross-section is studied by numerical calculation and model analysis.By establishing the finite element model of simply supported single plate with four edges at different angles,it is found that the elastic local shear buckling strength of steel webs decreases and the elastic global shear buckling strength increases with the increase of inclination angle A.Then,the finiteelement models with different inclination angles are established,eigenvalue buckling analysis and non-linear buckling analysis are carried out,and the buckling strength and actual shear strength of corrugated steel webs are obtained.Then,the shear strength curve is obtained.CoMPared with the curve of flat section corrugated steel webs established by Nie Jianguo,it is found that the difference between the two results is very small.Therefore,the calculation of equal section waves in Nie Jianguo is considered.Based on the formula of shear strength curve of corrugated steel webs,a reduction coefficient is selected and a formula for calculating the shear strength curve of corrugated steel webs with variable cross-section is obtained.