Retrofitting of Hot-Rolled Steel Channels Using CFS Sections: Experimental Study and Flexural Behavior

Abstract

This paper describes an experimental investigation aimed at retrofitting hot-rolled steel (HRS) channels using cold-formed steel (CFS) sections. Six simply supported specimens were tested under four-point monotonic loading. The main goal of this study was to improve lateral torsional buckling resistance by converting open HRS sections into closed sections (box type) by conveniently connecting CFS sections near the flange tips of the HRS channels. To determine the flexural benchmark parameters, one specimen was tested without being retrofitted. Four of the other specimens were retrofitted by inserting a CFS channel into the HRS section to form a box section and intermittently welding them at the flange tips along the span. The pitch of the welding varied in these four specimens. In the last specimen, a corrugated CFS plate was intermittently welded to the HRS section toward the flange tips to form a box section. The flexural performance of all specimens was evaluated in terms of ultimate strength, load-displacement response, stiffness behavior, lateral displacement, and mode of failure. The theoretical strength of the HRS channel was determined and compared with the test strengths. This study confirmed the substantial potential of CFS sections in retrofitting HRS channels under flexural loading.