Cold-Formed Steel Reinforcement for Improperly Cut Wood Composite I-Joists

Abstract

Wood composite I-joists have become an attractive option for floor joists in residential construction. One disadvantage of I-joists is the restrictions on hole size and the inability to notch the top compression flange. This technical paper evaluates two cold-formed steel reinforcers to strengthen I-joists that have been improperly cut—one to reinforce the top flange, and another to reinforce the web. The reinforcers were tested at various locations along the length of the beam. Based upon testing results, the notched I-joists with the flange reinforcers retained 60.2% of the strength and 77.0% of the stiffness of the original I-joists. The I-joists with the web hole and single-sided reinforcers retained 78.2%% of the strength and 95.7% of the stiffness of the original I-joists. I-joists with the web hole and the double-sided web reinforcers retained the I-joist strength and 95.1% of the stiffness of the original I-joist. These reductions in strength and stiffness can be used to determine if the reinforced I-joists are suitable for particular loading applications.