Experiments of Cold-Formed Steel Connections and Portal Frames

A series of connection tests which were composed of closed cold-formed steel sections were conducted to investigate the performance of the connections constituting a pitched roof portal frame. The flexural strength of the section was investigated first and the structural behavior of the connections including the moment-rotation relation, the yield, and ultimate moment capacity of the connections were studied experimentally. The connection test specimens consisted of column base, eave, and apex connections of the portal frame. The main factors of the connection test were the thickness and the shape of the mild steel connection element. Finally, the portal frame was tested under both constant vertical and increasing horizontal loads to failure. The experimental results were compared with the numerical analysis results. The semirigid connection concept was considered for the analysis of the portal frame using the secant stiffness of the connections, which were estimated from the momentrotation curves of the connections tested.