Finite Element Analysis of Postbuckled Shear Webs

An isolated panel subjected to shear distortion is capable of carrying a shear force well in excess of that causing initial shear buckling, even when the boundary flanges have no bending strength. A finite element method (FEM) analysis confirms the view that the postbuckling strength is attributable to a nonuniform shear‐stress distribution along the boundaries, varying from the critical stress in one corner up to the shear‐yield stress in the tension corner with no need for any diagonal tension. The presence of flanges with bending strength does permit the development of diagonal tension. However, light flanges give no increase in shear resistance. Impractically heavy flanges are shown to be capable of developing true diagonal tension, giving an increase in total shear capacity. The FEM analysis is applied to plate girders for which test results are known and is shown to provide reliable predictions.