Distortional–global interaction buckling of stainless steel C-beams: Part I — Experimental investigation

• Stainless steel beams tested featuring distortional-global interaction buckling.
• Specially devised test rigs offered clearly defined loading and boundary conditions.
• Material properties, geometric imperfections and member deformations recorded.

This paper presents experimental data for cold-formed stainless steel lipped channel beams featuring distortional–global interaction buckling. Three stainless steel alloys were employed in the tests, namely austenitic S30401, ferritic S44330 and lean duplex S32101. Coupon tests were carried out to determine the mechanical properties of the virgin sheet material as well as the work-hardened corner material of the press-braked sections. Geometric imperfections were measured for each specimen prior to testing. A total of 32 specimens were tested under four-point bending, six of which were tested with lateral bracing in order to determine the section capacity. The remaining 26 specimens, with spans ranging from 1.8 m to 4.0 m, were tested in a specially devised test set-up. The set-up featured a dual-actuator gravity simulator, flexible load-applying frames and idealized end support conditions, all of which contributed to minimizing uncertainties in the tests, thereby affording benchmark tests for analytical and numerical studies. Interaction buckling was observed in all tests of unbraced members.