STUDY ON TEMPERATURE DISTRIBUTION OF HIGH STRENGTH CONCRETE FILLED STEEL TUBULAR COLUMNS DUE TO FIRE
H. QI 1*, Y. DU 1, B. WANG 1, and R. Liew 2,1
1 College of Civil Engineering, Nanjing Tech University, Nanjing, China
2 Department of Civil and Environmental Engineering, National University of Singapore, Singapore
For concrete of 120MPa cubic compressive strength, adding polypropylene fibre can prevent concrete spalling at elevated temperature and steel fibre can improve the ductility. The present study tested the thermal properties of 120MPa concrete mixed with PP fibre and steel fibre. The test results show that increasing the amount of steel fibre will increase the thermal conductivity but reduce the specific heat capacity slightly. Experimental study on the temperature distribution of cross section of 120MPa complex fibre concrete filled steel tube specimens also have been conducted under ISO834 fire. It indicated that the heating rates of the specimens decreased with the section size increasing, and the temperature distribution on the cross section is non-uniform. In the further process of heating, the temperature difference between the steel tube and the furnace fire gradually decreased, and the effect of the cross section size on the heating rate of specimens decreased. Adding more steel fibre can induce more uniform temperature distribution. Furthermore, the thermal transfer numerical simulation was conducted by ABAQUS software, and traced the experimental results well.
High strength concrete; Steel fibre; Thermal property; Temperature distribution; Thermal transfer numerical analysis