Fabricated VHS tube to high-strength steel plate triangular concrete filled stub columns under axial compression load

This paper investigates the behaviour of six concrete filled fabricated very high strength (VHS) tube to high-strength steel plate triangular stub columns under axial compression load. The specimens are triangular in cross-section and consist of three high-strength steel plates connected to very-high strength steel tubes at the vertices. In this study high-strength plates of grade 450 were used. The VHS tubes are of 38mm diameter and 1.6mm thickness, have a nominal yield stress (fy) of 1350 MPa and nominal ultimate strength of (fu) 1500 MPa. Four international standards; the Australian Bridge Design Standard for Steel and Composite Construction (AS 5100.6-2004), the American Concrete Institute Standard (AC I318-2002), The British Standard of Steel, Concrete and Composite bridges (BS5400-2005) and the Chinese standard for concrete-filled steel tubular structures (DBJ 3-51: 2003), were used to predict the ultimate carrying capacities of the specimens and compared with the experimental results. New models are proposed based on mechanical properties of the heat-affected zone and plate buckling. Recommendations for future studies are made based on comparative studies.