Experimental investigation on performance of perforated cold-formed steel tubular stub columns

This paper describes an experimental study to estimate the stub columns capacity of cold-formed square (SHS) and rectangular hollow sections (RHS) containing two opposite central circular perforations at column mid-height. The stub columns were extracted from commercially available Tata Structura-YSt 310 tubular sections, with minimum yield strength of 310 MPa, conforming to Indian Standard 4923. The influence of two opposite central circular perforations on the structural performance of tubular steel stub columns under concentric loading was investigated for perforation size to flat width ratios up to 0.9 The local geometric imperfections, load-end shortening curves, strain distributions at mid height of column and typical failure modes observed from the present test programme are documented in this paper. Further, the ultimate column capacities recorded from the test programme are compared with codified design predictions as well as design equations proposed by various researchers. Based on the comparison, it is observed that the predictions made by most of the currently available design equations are conservative and reliable but generally scattered for design of cold-formed tubular structural steel stub columns having central circular perforations.