Elastic buckling of a centrally loaded simply supported I-section

Abstract Beams with an I-shaped cross-section (I-sections) are widely used in the building industry throughout Australia and internationally. The Australian Standard AS4100 provides guidelines for the design of such beams. Numerous failure modes are taken into account in these design rules including stability failure modes where such beams buckle out of their plane of loading. Recent failures of beams which have been designed according to the Australian Standard AS4100 have been documented and concerns have been raised that critical out-of-plane failure modes might not be included in the current version of this Australian Standard. A preliminary study on one such I-section was performed at the Centre of Construction Technology and Research (CCTR), University of Western Sydney. This preliminary study revealed that, for short beams, a failure mode exists that is not covered by the current design rules. The current paper documents these findings and proposes a simple failure model which could become the basis for the design against this failure mode.