Experimental investigation of post-fire mechanical properties of Q235 cold-formed steel. (May 2020)

• Record Type: Journal Article
• Authors: Ren, Chong; Dai, Liusi; Huang, Yuner; He, Wenfu
• Is Part Of: Thin-walled structures. Volume 150(2020)
• Publication Date: 2020-05
• Subjects: Cold forming process -- Cold-formed steel -- Mechanical properties -- Microstructure -- Post-fire -- Tensile coupon tests; Thin-walled structures -- Periodicals; 690.1
• DOI: 10.1016/j.tws.2020.106651
• Languages: English
• ISSNs: 0263-8231

Abstract

Abstract: Cold-formed steels are commonly used in construction applications. However, there is a lack of understanding on its post-fire mechanical properties. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed steels. The test specimens were cut from flat portion and corners of cold-formed channel sections, which were exposed to temperatures ranging from ambient temperature to 800 °C, and then cooled with water and air. The specimens are of grade Q235, with section thicknesses of 1 mm and 2 mm. The stress-strain curves and mechanical properties of the specimens were obtained from tensile coupon tests. Test results of post-fire mechanical properties are presented. Moreover, evolution of microstructure and fracture morphology of specimens with different cooling methods were examined. Finally, predictive equations are proposed for evaluating the post-fire mechanical properties of Q235 cold-formed steel channel sections. Graphical abstract: Image 1 Highlights: An experimental investigation of Q235 cold-formed steels was conducted to obtain their post-fire mechanical properties. The results showed that the post-fire mechanical properties were affected by cooling methods and temperatures. The difference of post-fire behaviour between the flat and the corner parts of cold-formed steel sections is discussed. New predictive equations were proposed to predict the post-fire yield strength, ultimate strength and ductility.