Research On Shear-lag Effect In Combined Box-girder With Corrugated Steel Webs

The research on the shear-lag effect in the simple-supported box-girder with corrugated steel webs (short for BGCW) was made in this paper. The first of all, the definition of shear-lag effect , analytical theories and methods were expatiated, and then ,based on the characteristics of bending deformation and stress distribution of BGCW was studied thoroughly by three methods including the model test , the 3-D finite element theory and the principle of minimum potential energy . After that, the influence of many factors such as the structural system, the geometric parameters ,the transverse acting location of external load and the non-liner mechanics characteristic of concrete , on the shear-lag effect of BGCW, was analyzed, the main geometric parameters of all was confirmed on. Finally the experiential calculating formulation for the effective flange width was achieved. The instructive conclusion was: 1) under the vertical loading, the shear-lag effect was produced badly, more severer under concentrated loading than under uniform loading .2) the longitudinal bending deformation of the beam flange was true of the imitating plane assumption of deformation . 3) the width length ratio (B/L) was confirmed as the first factor working on the shear-lag effect among all the geometric parameters;4) the shear-lag coefficient of simple-supported box-girder was severer than the continuous box-girder, the shear-lag effect in the inner supported section of continuous beam was much more severer, we need paying more attention for it in designing. 5) the non-liner characteristics of material deformation have littlie influence on shear-lag effect in BGCW. 6) the experiential calculating formulation and calculating diagram for the effective flange width was raised with the only factor of the width-span ratio., but the primary location of axis of bending moments should not be changed while calculating the inertial moment . The research on the bending behave and shear-lag effect in BGCW , will be helpful for understanding the bending mechanism and the calculation of ultimate bearing capacity of BGCW , and also distribute the far-ranging study and building of the same type box-girder bridge in China.