Carrying capacity of thin-walled cold-formed square hollow columns with large holes

Thin-walled cold-formed hollow columns are widely used in steel structure construction due to their advantages such as high strength, ductility and light weight. When bolted connections are realized, large holes may be used at the level of the connections in order to allow screwing the bolts and to avoid the use of long bolts along the width of the cross-section. This paper investigates the influence of these considerable holes on the resistance and stability of the column. More specifically, square hollow sections with large holes have been considered and their behaviour has been studied numerically using shell elements, accounting for both local and distortional effects, as well as material and geometrical non-linearities. The obtained results have been then compared with the predictions obtained through the code provisions for the cross-section resistance and member buckling.