Composite Cold-Formed Steel-Concrete Beams

Experimental study was conducted at the University of Windsor and a composite beam system using soffits made of cold-formed steel channels was developed. The test results show good characteristics of these beams, especially with regard to their ultimate load carrying capacity and bond strength. The study shows that by replacing the standard reinforcing bars into a cold-formed steel section of equal area, the structural performance of the beam could be almost unchanged, while saving is achieved in the cost of forms and shorings. Soffits made in the form of stiffened channels with embossments performed very well as integral parts of the composite beam. The combined action of the embossments and the channel's lips lead to excellent bond characteristics between the soffit and the concrete. This can be explained by the fact that the concrete has to be lifted up in order to slide over the embossments, while this movement is restrained by the lips of the channel.