Uniaxial behaviour of sand concrete-filled steel tube columns

Abstract

A major issue in the design of rectangular hollow section (RHS) steel columns is the local buckling ultimate limit state, which can seriously limit the overall resistance of the column. The use of concrete-filled steel tubes is frequently the solution that is adopted to overcome this problem, by enhancing the column resistance through the association of the resistances of the two materials. Major design codes contain rules for the design of composite columns, but the concrete's resistance is limited to the usual range of concrete classes. This paper presents the results from a series of experimental tests using low-cost/low-strength concrete, containing a small amount of cement and using sand as the only aggregate. This may be particularly advantageous from the logistic and economical points of view. The experimental results are presented, analysed and compared with those obtained for non-composite RHS steel columns. Finally, the Eurocodes design rules are used to assess their applicability to low-performance concrete.