Tests to Examine Compact Web Slenderness of Cold-Formed RHS

Abstract

This paper describes a series of bending tests to examine the influence of web slenderness on the rotation capacity of cold-formed rectangular hollow sections (RHS) for use in plastic design. The results indicate that the plastic web slenderness limits in design standards, which are based on tests of I-sections, are not conservative for RHS. Some sections, which are classified as compact by current steel specifications, do not demonstrate rotation capacity suitable for plastic design. The common approach in which the flange and web slenderness limits are given independently is inappropriate for RHS. There is considerable interaction between the webs and flange, which influences the rotation capacity, as shown by approximate isorotation curves. A proposal for a bilinear interaction formula between the web and flange slenderness limits for Compact RHS is given.