“…The main components of the structure are the uprights (columns) which are open thin-walled sections perforated to accept the tabs of beam-end connectors; the beams are often in the shapes of channels, hat-sections or rectangular boxes [1,2]. Investigations into rack structures have been made by various authors [2][3][4][5][6]. Davies [2] and Lewis [3] were primarily concerned with the stability of the structures.…”