Experimental and numerical assessments of hot-rolled carbon steel fixed-ended angles in compression

Abstract

Towers, trusses and bracings diaphragms generally utilise angles cross-sections. Although the angles represent one of the simplest steel cross-sections, their design and structural response are usually not simple. This paper addresses the behaviour of carbon steel hot-rolled equal-leg angle cross-section under compression subjected to the flexural-torsional buckling failure mode. The adopted methodology encompassed an experimental campaign consisting of eighteen full-scale tests on ASTM A36 carbon steel equal-leg angle columns. Three different cross-sections were utilised, L64x64x4.8, L76x76x6.4 and L102x102x6.4 corresponding to b/t (leg width to thickness) ratios of 13.33, 11.88 and 15.94, respectively. All investigated columns presented flexural-torsional buckling failure modes characterised by major axis bending accompanied by a cross-section rotation. This experimental programme was followed by finite element simulations, validated against the experimental results, taking into account the geometrical and material nonlinearities. These models were used to expand the database involving the flexural-torsional buckling response in fixed-ends hot-rolled angle columns made of carbon steel. Afterwards, the results were compared with Eurocode 3 (EC3) and modified DSM (mDSM) predictions. The EC3 presented more significant discrepancies when compared to experiments and numerical results, confirming the conservatism of this code. On the other hand, the performance of the mDSM method was significantly better.