Quasi-static responses and associated failure mechanisms of cold-formed steel roof trusses

Abstract The use of cold-formed steel trusses in roof framing has significantly increased recently. Cold-formed steel roof trusses are ideal and efficient systems for a variety of applications due to their design flexibility and ease of construction. Past research explored the behavior of these truss systems up to the ultimate capacity point; however, the inelastic behavior to the failure was not fully captured. Information about the response beyond the buckling point and the energy absorption capacities are missing and need to be investigated. In this paper, small-scale cold-formed steel roof truss specimens were tested to failure under quasi-static loading. The static resistance of these systems and the associated failure mechanisms were identified. Such information is key input when analyzing these roof systems under blast loads using the Single Degree of Freedom simplified technique. Experimental results and absorbed energy comparisons show that the truss layout and the shape of loading significantly affect the performance of the truss and the failure mechanism. Three-dimensional finite element models were developed and verified against the experimental results. The advanced models predicted the static resistance with a high level of accuracy. Experimental and finite element analyses have shown that the energy absorbed is improved significantly when the web members susceptible to buckling are strengthened.