shear lag effect, composite box girders with corrugated steel webs, energy variational method, spatial deformation, Building construction, TH1-9745

Composite box girders with corrugated steel webs (CBGCWs) have attracted increasing attention in bridge engineering. However, the shear lag effect has an impact on the mechanical behavior of thin-walled box girders and the impact of transverse deformation on this effect is usually neglected. In this study, a modified energy variational method is proposed to quantify the shear lag effect on CBGCWs. The shear deformations of each flange are analyzed based on the mechanical properties of the corrugated steel webs. A shear-lag warpage displacement function is introduced for each flange to account for the shear lag effect due to transverse deformation of the top flange. The formulation for the shear lag effect on CBGCWs is then derived using the principle of the energy variational method. The feasibility and accuracy of the proposed method are validated through a numerical study of a simply supported CBGCW subjected to uniform loading. In addition, a parametric analysis of the shear lag effect on CBGCWs is conducted. The results demonstrate that local bending deformation of the top flange leads to an uneven distribution of shear lag effects and the shear lag effect on corrugated steel webs is significantly influenced by the width–to–span ratio.