Experimental and numerical studies on cold-formed steel battened columns

Abstract

The compression performance of cold-formed steel battened columns was experimentally and numerically investigated in this study. Three types of built-up sections considered in this study were composed of two stiffened chord components and longitudinally distributed batten plates, which were assembled utilizing self-tapping screws. A total of 20 simply supported columns were tested under concentric compression. The experimental results in terms of loading capacity, failure mode and load versus shortening response were obtained and then employed to calibrate the finite element model. Furthermore, based on the verified finite element model, a parametric study was carried out to explore the effects of member slenderness, transverse distance between the chords and longitudinal batten spacing on the compressive strengths of the thin-walled battened columns. Underpinned by the results of 20 experiments and 216 numerical analyses, it was demonstrated that the nominal strengths by doubling the resistances of individual chord components determined using direct strength method were generally rather conservative and quite scattered for the cold-formed steel battened members undergoing compression. Additionally, the provisions specified in the AISI S100 with the shear stiffness reduction of built-up section members considered by the modified slenderness ratio were overall unconservative to predict the compressive strengths of the thin-walled battened columns. Therefore, modifications of the current design rules were proposed in this investigation to offer accurate strength predictions for the cold-formed steel battened compression members.