Design guidelines for SHS thin-walled columns with large holes at their extremities

Thin-walled cold-formed hollow columns are widely used in steel structure construction due to their advantages such as high strength, ductility and lightweight. When bolted connections are used, long bolts passing through the entire hollow cross-section are required. An alternative solution could be that large holes are made in one of the column faces, at the level of the connections, allowing thus the hand tightening of ‘short’ classical bolts. This paper investigates the influence of these holes on the resistance and stability of the column and aims at determining a safe way to compute the resistance of cross-sections and the stability of members in the presence of handholes. More specifically, square hollow sections (SHS) with large holes have been considered and their behaviour
has been studied numerically using shell finite elements, accounting for local and distortional effects as well as material and geometrical non-linearities. Then, the obtained results have been compared with the predictions obtained through the code provisions for cross-section resistance and member buckling, in order to check their adequacy.