STRENGTH OF CONCRETE-FILLED THIN-WALLED STEEL BOX COLUMNS - EXPERIMENT

An experimental study on the strength and deformation of concrete-filled square box stub-columns is presented. Six specimens of concrete-filled composite columns were tested under cyclic compressive loads. For comparison, four specimens of steel columns were also loaded to failure. The ultimate strength, ductility, and collapse behavior of the two types of columns were compared. In the comparison, the effect of width-thickness ratio and stiffener rigidity on the behavior of the columns was examined. The study showed that high strength and high ductility can be expected from the concrete-filled composite column. In the case of concrete-filled composite columns, an empirical reduction factor that accounts for the effect of the size of the filled-in concrete prism and the concrete strength class was introduced in evaluating the compressive strength of the concrete, and the local buckling strength of the plate panel in composite columns was then compared with available empirical design formulas for a thin-walled steel member in compression.