ANALYTICAL STUDIES ON CONCRETE FILLED STEEL TUBES

In recent years, as a type of hybrid system, the concrete-filled steel tubular (CFST) columns are increasingly used in buildings and bridges. In concrete-filled steel tube (CFST) columns, the steel tube provides formwork for the concrete, the concrete prolongs local buckling of t he steel tube wall, the tube prohibits excessive concrete spalling, and composite columns add significant stiffness to a frame compared to more traditional steel frame construction. The design of concrete filled steel tubes is considered to be difficult since a proper formula is not present to find out the axial load carrying capacity of such CFST short columns.