Abstract
The concrete-filled steel tubular columns are expected to have many excellent features. Among these, we expected the effect of multiplication that the fullfilled concrete prevents the local buckling of the column walls as well as they restrain the concrete like the hoop reinforcements. This results in the excellent improvement of the stiffness, ultimate strength and deformation capacity of the columns. In this paper, these effects are explained from the experiments of the stub-columns and subassemblages where the column width-to-wall thickness ratio is chosen as an experimental parameter. It is noted that these multiplication effects are evidently recognized as the width-to-thickness ratio becomes large.
