Design of Stainless Steel Roof Sections (No. R851)

Abstract

This report describes the influence of flange curling on cross-sectional properties and critical elastic buckling stresses of two wide-flanged roof sections (commercially available Monoclad and Megaclad). Results show that modified geometries due to flange curling can cause an increase of critical buckling stress ranging from 1.10 to 3.41 times that based on original geometries ignoring flange curling. Furthermore, the section modulus can be lowered from 6% to 16.9% due to flange curling deformations for the sections investigated. Flange curling was most significant for the more slender Megaclad section. The current proposed DSM design curve for the distortional buckling of stainless steel sections (Lecce and Rasmussen 2005a) and the Winter curve for local buckling are generally more conservative than the current North American Standard Appendix 1 (2004) DSM formulations. The design moment capacities alter due to flange curling and for distortional buckling there was an increase of up to 10.6% but a net decrease of up to 12.2% for local buckling. Given the current data, it would be prudent to ignore the effects of flange curling for distortional buckling but it would be necessary to consider them for local buckling.