Numerical Simulation of 3-D Temperature in Reinforced Concrete Structure under Fire

Calculating the change of temperature field in reinforced concrete under fire is very important for the analysis on the change law of intensity, deformation and fire resistance performance in high rise building construction. Based on the unsteady three-dimensional heat conduction differential equation, the discrete equation of unsteady three-dimensional temperature field under fire is established with control volume method. Comparison between the numerical results of the unsteady temperature field for the reinforced concrete slab in fire and the tested data shows that they are basically identical. Computation of one reinforced concrete corner in fire, made up with slab, beams, column and brick walls, is conducted and related results are presented. The result shows: the temperature distributions of the surfaces exposed to fire in all directions is not uniform and the integral structure temperature field calculation of building under fire is a problem that should be considered in three dimensional method. The wave-like temperature distribution is showed in the exposed surface because of the steel bars. The fire resistance analysis of the slab and column which are viewed as a whole should be considered simultaneously.