Shear Lag Effect And Experimental Study Of Single-box Twin-cell Steel-Concrete Composite Box Girder With Corrugated Steel Webs

As a new structure,the Single-box twin-cell steel-concrete composite box girder with corrugated steel webs has the advantages of light weight,convenient construction process and superior structural performance.In this paper,based on the research results of shear lag effect of existing corrugated steel web composite box girder,based on the energy variation principle,the shear lag effect of this type of box girder structure is studied from three aspects:theoretical analysis,space finite element and model test.The main work and research conclusions are as follows:(1)For the Single-box Twin-cell Steel-Concrete Composite Box Girder With Corrugated Steel Webs,assuming two different warping displacement functions,and the shear hysteresis control differential equation is derived according to the energy variation principle,and the general form of the solution is obtained by combining the boundary conditions.For the simply supported beam,cantilever beam and continuous beam,the analytical solutions of deflection,additional bending moment,bending normal stress and shear lag coefficient are obtained respectively.(2)According to the model beam size,the finite element software ANSYS is used to establish the three-dimensional refined finite element model,and the shear lag effect of the simply supported beam,cantilever beam and continuous beam under transverse load displacement is analyzed.It can be seen from the analysis results that under the same load,the shear lag effect is most prominent when the load acts on the middle web.The overall trend is that the shear lag coefficient peaks at the position of the load and gradually decreases from the peak to the both sides.(3)According to the scale ratio of 1:5,a single-box double-chamber corrugated steel web steel-mixed composite model beam was fabricated,and the model beam was loaded and tested.The measured values were compared with the theoretical values and the finite element results.It can be seen from the comparison results that the overall trend of the three values is basically the same,and the error is within the reasonable range;under the same load size,the stress value of the lower wing is much larger than the stress value of the upper wing;the edge value of the upper wing is less than the two The stress value of the upper wing in the middle of the plate;the shear lag effect of the box girder under concentrated load is greater than the uniform load.(4)For the influence of structural geometric parameters and prestress on the shear lag effect of box girder,this paper takes wide-span ratio,high-span ratio,overhang ratio,roof thickness and pre-stress as the research object,and establishes different size models through finite element software.The variation law of the maximum shear lag coefficient of themid-section of the box girder is analyzed.According to the analysis results,the influence of geometric parameters on the shear lag effect of box girder,the wide span ratio and the thickness of the roof are the main influencing factors;while the prestressed stress has little effect on the shear lag effect of box girder.Under general conditions,the influence of prestressing force can not be considered.