Flexural capacity of hollow flange beams

The hollow flange beam (HFB) is a unique cold-formed steel section develope d in Australia for use as a flexural member. Research has identified that t he HFB section's flexural capacity for intermediate span members is limited by lateral distortional buckling, which is characterized by simultaneous l ateral deflection, twist, and web distortion. This buckling behaviour is ma inly due to the unique geometry of the section, comprising two torsionally stiff triangular flanges connected by a slender web. This paper presents a finite element analytical model suitable for non-linear analysis of HFB fle xural members. The model includes all significant effects that may influenc e the ultimate capacity of such members, including material inelasticity, l ocal buckling, member instability, web distortion, residual stresses, and g eometric imperfections. It was found to accurately predict both the elastic lateral distortional buckling moments and the ultimate capacities of HFB f lexural members, and was therefore used in the development of design curves and suitable design procedures. (C) 2000 Elsevier Science Ltd. All rights reserved.