FIRE RESISTANCE OF CONCRETE COLUMNS WITH RECTANGULAR CROSS SECTION SUBJECTED TO 2-ADJACENT- FACE AND 3-FACE HEATING

Using a numerical program RCSSCF, this paper studies the influence of several parameters, such as axial load ratio, effective length, sectional dimension, load eccentricity ratio, reinforcement ratio and load angle, on the fire resistance of reinforced concrete columns with rectangular cross section subjected to the ISO834 standard fire and 2-adjacent-face, or 3-face heating. 9792 hypothetical cases of columns subjected to 2-adjacent-face heating, and 11520 hypothetical cases of columns subjected to 3- face heating are selected for fire response analysis. Different axial load ratios, effective lengths, cross section dimensions, load eccentricity ratios, and load angles are considered in the analysis. Based on the simulation results, a practical method is proposed for calculating the fire resistance of reinforced concrete columns with rectangular cross section subjected to 2-adjacent-face heating, or 3-face heating. The simulation results indicate that: a) reducing the axial load ratio is an effective measure to improve the fire resistance of columns with rectangular cross section. b) the influence of load angle on the fire resistance of columns with rectangular cross section subjected to 2-adjacent-face heating, or 3-face heating is significant. c) the difference between the fire resistance of the columns with rectangular cross section subjected to 2-adjacent-face heating and that of the columns subjected to 3-face heating decreases with the increasing of axial load ratio.