Fire resistance of reinforced concrete columns subjected to 1-, 2-, and 3-face heating

Currently, the design of reinforced concrete (RC) columns is essentially based on tabulated data. A more scientific approach based on an understanding of the fundamental behavior of columns in fire is useful to structural engineers. Tan and Yao in 2003 developed a simple and rational design method to predict the fire resistance of 4-face heated RC columns. The predictions of the proposed method agree well with test results. The same method can be extended to 1-, 2-, and 3-face heated columns with some modifications. The effects of elevated temperature on material deterioration with regard to the strength and stability of columns are quantified. Furthermore, the shift of neutral axis due to nonsymmetric heating is predicted in the proposed method. For columns under 1- or 3-face heating, only uniaxial bending needs to be considered, but for 2-face heating, the effect of biaxial bending is taken into account. A finite element code SAFIR, developed at the University of Liege, Belgium, was used to benchmark the proposed simplified calculation method.