Buckling behaviour of stiffened hollow flange beams

The Hollow Flange Beam (HFB) is a new cold-formed and resistance welded section developed in Australia. Due to its unique geometry comprising two torsionally rigid triangular flanges and a slender web, the HFB is susceptible to a lateral distortional buckling mode of failure involving web distortion. An investigation using finite element analyses and experiments showed that the use of transverse web plate stiffeners effectively eliminated lateral distortional buckling of HFBs and thus any associated reduction in flexural capacity. This led to the development of a special stiffener that is screw-fastened to the flanges on alternate sides of the web. This paper presents the details of the investigation and the results.