An Experimental Investigation on Concrete Filled Steel Tube Columns Under Axial Compression

Abstract. This paper presents an experimental investigation on the behaviour of concrete filled steel tube columns under axial compression. The steel columns were filled with self-compacting and self-curing concrete instead of normal conventional concrete. A test program consisting of square column, circular column and rectangular column was firstly conducted. The behaviour of three concrete filled steel tubular sections (CFSTs) under axial load is presented. The effect of steel tube dimensions, shapes and confinement of concrete are also examined. Measured column strengths are compared with the values predicted by Euro code 4 and American codes. Euro code 4, gives good estimation of self-compaction concrete. However, lower values as measured during the experiments were predicted by the American Concrete Institute (ACI) equation. Also, the effect of thickness of steel tubes, concrete cube strength and steel percentage is also studied. In addition to CFST column the steel tube also acts as confinement for concrete.