New Design Rule for Intermediate Transverse Stiffeners Attached on Web Panels

Abstract

The equation for the required area of the intermediate transverse stiffener stipulated in the current AASHTO and AISC specifications was derived under the assumption that the transverse stiffener is subjected to an axial compression resulting from diagonal tension developed in the postbuckling stage as noted by Basler in 1963. However, the area requirement is known to be overly conservative. A recent study by Lee et al. in 2002 reported that the transverse stiffener is not necessarily subjected to an axial compressive force during postbuckling of the web panel and hence the current area requirement can be eliminated. The study also reported that the flexural rigidity should be increased several times higher than that required for elastic shear buckling in order for the web panel to develop its potential ultimate shear strength. In the present study, an experiment was conducted in order to investigate the behavior of the transverse stiffeners during postbuckling. The test results confirmed the earlier findings. A new design rule for the sizing of the transverse stiffeners is formulated through extensive nonlinear finite element analysis data verified by test results.