Response and failure mechanism of tubular steel columns subjected to close-range explosions
A close-range blast event can cause severe damage to building structures due to its ability to produce very high localised impulsive loads. Such events can result from explosives that are attached to the critical elements of a structure, backpack and suitcase explosives, and vehicle or parcel bombs targeting the key structural elements of buildings and bridges. Steel hollow sections are among the most commonly used prefabricated structural element types that are widely used in Australia. Therefore, adopting the necessary precautionary measures in the design of such elements against close-range blast is worthwhile to explore. This paper focuses on an experimental and numerical study performed on concrete-filled and hollow square tubular columns (100 x 5 mm SHS Grade C350) made out of cold-formed structural steel hollow sections (SHS) that were subjected to highly explosive TNT charges. The charges were placed above the top surface of the column at two different scaled standoff distances of 0.12 m/kg1/3 and 0.15 m/kg1/3. The failure mechanism and the pressure development of the hollow and concrete-filled columns are discussed and presented. The advantages of using concrete as an infill material for reducing the structural damage are also discussed.