Experimental investigation of global-distortional interaction buckling of stainless steel C-beams

Abstract

This work reports the test data for press-braked stainless steel C-beams subjected to global-distortional (G-D) interaction. The chemical constituents of austenitic S30408 used in the tests were proved to meet the European (EN 10088–1:2014) and Chinese (GB/T 3280–2015) codes. The tensile test of the material was performed to determine the mechanical properties of the flat and corner areas of the press-braked C-beams. Initial imperfections of each specimen were assessed before conducting the bearing capacity tests. A total of 10 specimens consisting of 20C-beams were subjected to four-point bending. All specimens first underwent distortional buckling and then global buckling. The vertical displacement at the mid-span and the loading points, support rotation, distortional deformation, lateral deformation, strain at the boundary of the upper flange as well as strain of the lower flange were meticulously recorded and analyzed. Based on the observed test phenomena, the recorded displacement and strain data, the failure mechanism of G-D interaction and the development of the buckling waves were unveiled. The test data was employed to evaluate the accuracy of the design methods in accordance to the Direct Strength Method (DSM), EN 1993-1-4, AS/NZS 4673 and ASCE 8–22. All codes are found to account for distortional buckling by employing the Effective Width Method (EWM) to reduce the compression plate area. The evaluation results revealed that DSM could safely and stably make a prediction of the ultimate capacity for G-D interaction in stainless steel beams, while EWM have a lower performance in prediction.