Structural behavior of cold-formed steel header beams

The purpose of this experimental and analytical study was to define the structural behavior of cold-formed steel header beams subject to a combined bending and interior-one-flange loading (IOF) condition as typically occurs in cold-formed steel framed wall construction. A header beam is a structural member that spans window and door openings. The header beam is built-up from cold-formed steel C-sections and cold-formed steel track sections. The C-sections and track are interconnected using self-drilling screws. This study focussed on the IOF loading behavior for both back-to-back (I-beam) and box-beam configurations. Previous research conducted in the area of web crippling strength, bending strength and flange buckling of cold-formed steel members was reviewed and is discussed. The data obtained from the experimental study was analyzed and evaluated to determine the interaction between bending and web crippling for the loading configurations used. The findings of this study were used to establish a design methodology for header beam construction that represents the behavior of these members. New design equations and recommendations for the design of header beams is presented.