Distortional Buckling of Thin-Walled Beams/Panels. II: Design Methods

The design of standing seam roof panels must necessarily consider two loading conditions; construction and in use (occupancy) loading, in addition to the effects of ponding if sufficient drainage or specific drainage mechanisms are not provided to avoid accumulation of water. In the present paper, the results of tests on single panels with laterally unsupported compression flanges are presented along with two design methods for the interaction between local and distortional buckling. The design method is based in the analytical expression presented in the first paper and is conceptually consistent with the design procedures currently used for flexural, torsional, and lateral-torsional buckling. Overall, the new design methods give better approximations of the maximum capacity of wide-flange standing-seam panels than previous design methods. More research is still needed to demonstrate the applicability of the methods presented here to full-scale panel systems in which the outstanding legs are crimped together.