Eaves connections of double-bay portal frames with staggered single channel cold-formed rafters

Experimental tests were performed to evaluate the structural performance of the eaves region of double-bay portal frames with staggered cold-formed rafters. This region represents the distance from the point of maximum moment at the eaves joint to the point of zero moment (contraflexure) in the rafters and columns respectively. The column and two rafter members are formed from single cold-formed channel sections, which are bolted back-to-back at the eaves joint. In order to simplify the connections the rafters are connected directly to the back of the web of the column at different levels. Particular attention was focused on the failure modes of the structures, the strength (resistance to moment) of the connection, the moment-curvature performance and the connection’s ability to form plastic hinges. In all the tested structures, the column failed by local buckling in the compression flange and web, between the upper and lower rafters. The moment-curvature graphs proved that plasticity could not be achieved in these connections.