Negative Shear Lag in Cantilever Box Girder with Constant Depth

Shear lag and negative shear lag effect in cantilever box girders are analyzed through a variation approach and finite element techniques. The complex distribution of bending stresses under symmetrical loading on the flanges of cellular sections are also presented. In this paper, the supposition of the spanwise displacement on flanges follows a quartic parabolic variation. However, expressions are derived to determine the region of negative shear lag effect with the interrelation of span/width parameters involved. The theoretical results thus obtained are compared with a plexiglass model test. Finally, conclusions are drawn with regard to further study and research.