Comparative study on the fire performance of concrete-filled steel tubular and steel tube-confined reinforced concrete columns

This paper investigates the behaviour of concrete-filled steel tubular (CFST) columns and steel tubeconfined reinforced concrete (STCRC) columns when subjected to non-uniform fire conditions. CFST and STCRC columns exhibit enhanced sectional capacity compared to traditional reinforced concrete and demonstrate superior fire performance relative to steel columns. Because of their many advantages, CFST and STCRC columns are widely employed in the construction industry. However, limited research has been conducted on CFST columns and there is a notable absence of studies on STCRC columns exposed to non-uniform fire. Initially, finite element (FE) models of CFST columns and STCRC columns are developed for validation. To validate the models, a comparison of the results of FE models and tests is performed on the basis of temperature distribution, fire resistance and lateral displacement. A parametric analysis is then carried out to examine the impact of the various fire scenarios including 1-sided, 2-sided, 3-sided and 4-sided exposure on CFST and STCRC columns. Finally, the thermal-structural performance of the CFST and STCRC columns is compared. It is observed that the STCRC columns perform better than the CFST columns in nonuniform fire exposure. The observed comparisons and outcomes can help enhance the overall fire resilience of the buildings.