Small-Scale Test Behavior of Cold-Formed Steel Roof Trusses

Abstract

Twenty three small-scale roof trusses were fabricated from cold-formed steel and tested to ultimate capacity. Each specimen was subjected to a single point load at the ridge. One series of specimens was fabricated with a hinge connection at the ridge while a second series had a gusset plate connection at this location. The hinge served to isolate the strength properties of the heel connection and upper chords while the addition of the ridge plate provided information that could be used to quantify the load sharing between the ridge and heel connections. The performance of several heel plate configurations, altered by adding edge stiffeners and varying their shapes and thicknesses, was evaluated. Local buckling of the top chord adjacent to the heel plate was the predominant failure mechanism in combination with distortion of the heel plates in instances where the plates were inadequately stiffened. Methods of reinforcing the top chords to prevent local buckling were investigated.