Flexural behaviour of beams made of cold-formed steel sigma-shaped sections at ambient and fire conditions

This article reports a series of flexural tests at ambient and fire conditions on simply supported cold-formed steel beams made of one or two sigma-shaped profiles. It was assessed the critical temperature and time as well as the effect of the stiffeners on the beams under different restraining conditions, including no restraints, partial axial and beam supports rotational thermal restraints. The results showed that beams with web stiffeners may have different structural response in fire depending on the section shape. The beams without web stiffeners and not axially restrained presented the best structural behaviour under fire conditions.