Behaviour and design of aluminium hollow sections subjected to transverse blast loads

Experimental and analytical investigations of metal beams subjected to transverse blast loads have predominantly focused on solid metal cross-sections. In applications such as the secondary structural members used in facade structures the cross-sections consist of thin-walled aluminium hollow profiles. This paper presents an experimental study of 73 aluminium square hollow sections subjected to transverse blast loads by application of explosives. Four different section slenderness values and three different lengths were investigated, resulting in a wide range of length/depth ratios typical to facade structures. A semi-empirical analytical solution is presented whereby existing theory developed by others for solid metal sections is modified to account for local section deformations that occur in blast-loaded hollow sections. The technique considers both the energy dissipated in local deformations and the resulting reduction in the section-bending modulus, and furnishes a solution that bounds the experimental results with reasonable accuracy. A general design procedure is outlined that may be based on a final permanent deformation or a failure load, and the limitations of such a procedure are discussed.