ANALYSIS ON AXIAL COMPRESSIVE BEARING CAPACITY OF CIRCULAR CONCRETE-FILLED STEEL TUBULAR STUB COLUMNS WITH INTERNAL PROFILED STEEL UNDER DIFFERENT STEEL RATIO

This paper presents a finite element (FE) model of concrete filled steel tubular (CFST) stub columns with internal profiled steel under axial compressive load using ABAQUS. The FE model was verified by experimental results in the literature. The mechanical behavior of CFST stub columns with internal profiled steel was analyzed by dividing the total sectional steel into steel tube and the internal profiled steel. The load distribution between different components of the column and the axial compressive stress-strain curves were calculated and compared with those of the CFST columns without internal profiled steel. The influence on load-bearing capacity of the steel ratios in the steel tube and internal steel under the same total steel ratio was investigated, and quantitative analyses were conducted by amplification factor IdexN_c of load-bearing capacity and amplification index IdexN_s of load-bearing capacity of CFST stub columns with internal profiled steel. The load-bearing capacity of CFST stub columns with internal profiled steel is lower than CFST columns without internal steel in general, and the ratio of steel tube is a factor that significantly influences the load-bearing capacity. The results show that the ratio of the outer steel tube should be no less than 60% of the total steel ratio.