The Bar Simulation Method Of Shear-lag Effect In The Composite Box Girder With Corrugated Steel Web

The composite box girder with corrugated steel webs is a special form adopted inthe bridge. It can reduces the workload of bridge construction with corrugated steelwebs instead of the traditional concrete webs,and its force is clear,so that the use ofthe form is more widely.This article focuses on shear-lag effect in the simple-supported box-girder withcorrugated steel web. According to box-girder with corrugated steel webs forcecharacteristics,that the steel webs bears the most of the shear force and the top andbottom concrete slabs bears the moment of lexure chiefly.This accord the the principleof bar-simulation method.The principle of bar-simulation method is the web bears theshear force only and slab bears the moment of lexure. So we suggest the simplybar-simulation method to research shear-lag effect. This thesis has finished thefollowing works:(1)The first,the definition of shear-lag effect、analytical theories and methodsare expatiated,then the foreign and domestic researches about composite box girderwith corrugated steel webs are introduced.(2)The second,based on the principle of bar-simulation method derived fromcorrugated steel box-girder webs analogy bar area and differential equations.Then itintroduced spline function approximation method of solving. Taking use of boundaryconditions and deformation equations form16n equations.The finally designingMATLAB procedures solve the equations.(3)The third, by two simple beams and a continuous beam model tests, finiteelement ANSYS analysis and bar-simulation method compute, we analysis theshear-lag effect. The results of theoretical calculation and experimental results arebasically the same. That also verified the accuracy of bar-simulation method matchshear lag effect.(4)Taking use bar-simulation method, we analyse affecting of shear lag factorand the extent of affecting. And finally the experiential calculating formulation for theeffective flange width is achieved.(5) Through experimental research and theoretical analysis we find that:①corrugated steel box-girder webs under concentrated loads is greater than the uniformload about the shear-lag effect and the roof’s is greater than the bottom’s;②the shear-lag effect in the inner supported section of continuous box-girder is severer thanother sections.;③the width length ratio(B/L) was confirmed as the fast factorworking on the shear-lag effect among all the geometric parameter;④the extent ofshear lag effect is very limited;⑤the variation of shear-lag coefficient near bearing isvery large.