Hysteretic behavior of square concrete-filled thin-walled steel tubular columns with ribs

The hysteretic behavior of nine square concrete-filled thin-walled steel tubular (CFTST) columns with ribs was investigated experimentally and the failure mode, hysteretic behavior and energy dissipation capacity were examined. The main parameters in the study are the axial load level and the arrangement of ribs. Experimental results indicate that the axial load level has a great influence on the hysteretic behavior of CFTST columns. Specimen with four ribs and axial load level below 0.5 has plump hysteretic loops, better ductility and energy dissipation capacity. Slight pinch phenomenon is observed for two kinds of rib specimens. The ductility of CFTST columns decreases significantly when the axial load level is greater than 0.5. Columns with two kinds of rib arrangement have almost the same load capacity, while the ductility and hysteretic behavior of columns with four ribs is better than that of columns with two opposite ribs under same axial load level. Finally, a non-linear finite element analyses is carried out by using the ABAQUS6.4. The analytical results are in good agreement with the test results and this provides a favorable foundation for further study.