Experimental and numerical investigation of cold-formed steel double angle members under compression

Abstract

This paper presents a numerical and experimental study of double angle members connected by batten plates under concentric and eccentric axial compression. The number of batten plates is varied to study the influence on the nominal axial strength. Numerical analyses are able to accurately predict the behavior and strength found in the experiments, except for long columns under eccentric axial compression where the composite section failed in major-axis flexural buckling. Two design hypotheses are compared to the results obtained: (i) non-composite action (no interaction between angles), with only local, flexural, and flexural-torsional buckling considered; and (ii) composite action (full interaction between angles), and the only considering local and minor-axis flexural buckling of the pair of angles. The two design hypotheses ignore load eccentricity. Numerical and experimental results for angles connected by bolted batten plates fall in between the design curves defined by methods (i) and (ii), while angles connected by welded batten plates have greater strength than the design curve defined by method (ii). The use of batten plates significantly increases the strength of the system, especially for members under eccentric compression. However, the strength remains constant after a certain number of batten plates are connected, and after a minimum batten plate width is reached.