Numerical Analysis Of Shear Lag Effect Of Corrugated Steel Web Box Girder Based On Refined Analysis Model

Since the end of the last century,a large number of large-span prestressed concrete continuous box-girder bridges have been built in China.With the maintenance,testing,and monitoring of such bridges,it has been found that the deflection and cracks of such bridges have developed over time due to their self-weight.The problem is rather prominent.Excessive deflection or excessively rapid crack development obviously affect the normal use of the bridge.In recent years,concrete composite box beams with corrugated steel webs have gradually developed.As a new type of composite structure,the bridge has fully utilized the advantages of steel and concrete materials.With the advantage of its own weight reduction,it has solved the beam deflection and the belly The problem of plate cracking has significant economic and social benefits.However,there are few analyses on the shear lag effect of this type of bridge in China.In this paper,the numerical simulation method is used to analyze the influence of different factors on the shear lag effect of the bridge,as well as the traditional and refined analysis models in the shear lag effect.Comparison of differences in analysis.The main contents of this paper are as follows:(1)The simple supported corrugated steel web PC composite box girder with single box is selected as the object to analyze the shear lag effect of this type of box girder under the action of concentrated load and uniform load.The energy variation method is used to derive the calculation formulas of the stress and shear lag coefficient of the roof at mid-span and other cross-sections.An example is used to calculate the stress and shear lag coefficients of the roof.(2)Use Midas FEA to establish the model of corrugated steel web PC composite simply supported box girder calculated in the example,and find the bending normal stress at each position of the upper and lower wing plates of the box girder section under the action of concentrated load and uniform load.Calculate the shear lag coefficient,and compare it with the results of the analytical method.The results of the two methods are relatively consistent,and the change trend of the shear lag coefficient is consistent.Mutually confirmed the correctness of the finite element method and the analytical method.(3)The influence of the thickness of the roof,the wave height of the corrugated steel web,the prestress and the cantilever ratio on the shear lag effect of the PC composite box girder with corrugated steel web were analyzed.It can be seen that among the above four factors affecting the shear lag effect,the main factor affecting the shear lag effect of the roof is the thickness of the roof,and the wave height of the corrugated steel web,the prestress size,and the ratio of the cantilever to the shear The effect of hysteresis is not significant and can be ignored.(4)Relying on the Qilihe Zijin Bridge project,the shear lag effect of the mid-span and fulcrum sections of the long-span corrugated steel web prestressed concrete continuous box girder bridge is analyzed.The bridge system model is built by Dr.Bridge and Midas FEA And spatial finite element refined analysis model.Select the mid-span section and the fulcrum section as the analysis objects,solve the shear lag coefficient,and draw a line chart to intuitively see that in the mid-span section,the roof exhibits a positive shear lag effect,and at the fulcrum section,the roof exhibits a positive shear lag effect.