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

• Published in: Engineering structures 2021-03, Vol.231, p.111741, Article 111741
• Main Authors: Bondok, Doaa, Salim, Hani, Urgessa, Girum
• Format: Article
• Language: English
• Subjects: Blast loads; Buckling; Cold; Cold working; Cold-formed steel; Cold-formed steel trusses; Energy; Energy absorption; Failure analysis; Failure mechanisms; Finite element method; Finite element simulation; Large deformations, quasi-static tests; Load resistance; Mathematical models; Roof trusses; Roofs; Steel; Steel structures; Three dimensional models; Trusses
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.111741

•The static resistance and the associated failure mechanisms of cold-formed steel roof trusses were determined experimentally.•Advanced three-dimensional numerical models predicted the resistance and the ultimate failure mode.•The truss layout and the shape of loading significantly affect the performance of the truss and the failure mechanism.•For moderate damage levels, strengthening compression web members improve the absorbed energy. 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.