| Twenty-three small-scale and ten large-scale roof trusses fabricated from light gauge cold-formed steel were tested to ultimate capacity under panel point loadings. The small scale specimens were 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 served to quantify the load sharing between the ridge and heel connections.; As testing of full-scale specimens progressed, various practical means of increasing their capacity were investigated. While gusset plates at the heel connections in bearing were a significant factor in strength determination, local buckling of the top chord adjacent to the heel plates was the predominant failure mechanism. Trusses that experienced this local buckling failure exhibited post-buckling ductility whereas failures at the connections in bearing were sudden.; Design load outputs from truss design software were found to be conservative as were the design values obtained from using beam-column analysis in accordance with S136-01. Linear, elastic finite element analyses were remarkably effective in predicting zones of high stresses and locations where local buckling would be of concern with regard to design. |
