Shear Lag Effect Of Steel-Concrete Composite Beams Deck Considering Axial Force

As steel-concrete composite beams are more and more widely used in bridge engineering,from simply supported composite beams in the early 19 th century to composite beam suspension bridges and composite beam cable-stayed bridges today,more and more bridge structures have adopted such components.Shear lag effect,as a factor that must be considered in bridge design and construction,is becoming more and more complicated in composite beams.Although the effective distribution width of simply supported and continuous structures in composite beams is stipulated in the current codes in China,there is no definite stipulation and calculation method for shear lag effect of composite beams under the joint action of bendings.Therefore,it is necessary to study the shear lag effect of steel-concrete composite girder bridge under axial force.Based on engineering,this paper carries out numerical simulation and theoretical analysis.The main research contents are as follows:The development history of composite beams and self-anchored suspension bridges,the development of shear lag effect,research methods and the problems existing in current codes are summarized.Midas full-bridge modeling and Abaqus substructure solid element modeling are carried out for the supporting project,and the substructure model is checked by Midas bar model to prove the correctness of the modeling method,and then the influence of additional axial force on the shear lag effect of composite girder bridge deck is analyzed,and the relevant laws are obtained.Based on the conclusion of energy variational method and numerical simulation,the normal stress and shear lag coefficient of bridge deck without considering slip effect of cantilever beam under the combined action of axial force and concentrated load are theoretically deduced.Based on the substructure solid element model of the supporting project,the thickness of the bridge deck,the concrete strength grade and the thickness of the web plate of the steel main girder of the composite beam are parametric analyzed,and the influence of these three parameters on the shear lag effect of the bridge deck under the same load is obtained by changing the parameters.The typical section of the stiffening girder of the supporting project is selected as the calculation section to calculate the normal stress and shear lag effect of the bridge deck along the longitudinal bridge direction under the action of dead weight,secondary load,intermediate load and eccentric load of the stiffening girder,and to analyze the variation law of the normal stress and effective distribution width of the bridge deck under different working conditions,so as to provide a reference for the design of similar bridges.