Flexural rigidity of cold-formed steel built-up members

• Published in: Thin-walled structures Vol. 140; pp. 438 - 449
• Main Authors: Phan, Dang K., Rasmussen, Kim J.R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2019
• Subjects: Built-up member; Cold-formed steel; Discrete fastener; Flexural rigidity; Flexural rigidity; Cold-formed steel; Built-up member; Discrete fastener
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2019.03.051

Cold-formed steel (CFS) built-up members are formed by connecting several single members by fasteners. This paper presents experimental, numerical and analytical studies on the effect of fastener configurations on the flexural rigidity of built-up sections. In this research, two zinc-coated steel C-sections are connected back-to-back to form a double-web built-up I-section, which is subject to weak-axis bending. A closed-formed expression for the flexural rigidity of built-up sections as a function of fastener stiffness, number and position of fasteners, and section geometry is then derived. This is validated against the tests and finite element modelling, and can be adapted more generally to determine the stiffness and global strength of CFS built-up members in bending. •The study is about how fastener configurations affect the effective flexural rigidity of cold-formed steel built-up sections.•Tested fasteners are screws, bolts and welds.•The effective flexural rigidity is a function of fastener stiffness, number and position of fasteners, and section geometry.•Effective flexural rigidity affects stiffness and strength of built-up members in bending and members subject to buckling.