FIRE RESISTANCE DESIGN METHOD OF AXIALLY LOADED REINFORCED CONCRETE COLUMNS

The main objects of this paper are axially loaded reinforced concrete columns under the condition of four-face heating. Based on a lot of numerical analysis using finite element program for the reinforced concrete temperature field developed by the authors, a concept of mean strength reduction factor of material is introduced, the time-dependent material properties are established, and a simple design method which is similar to the design method used for reinforced concrete columns at ambient temperature is proposed. This design method is not directly dependent on the temperature field of the reinforced concrete cross-sections, and is only determined by the fire exposure time, so it is very convenient for design engineers. At last, the comparison between the experimental data and the theoretical results shows that the proposed fire resistance design method of axially loaded reinforced concrete columns is effective and safe.