Abstract:

In order to investigate the temperature of the frame structure exposed to fire , the variation of smoke temperature in the compartment with time is simulated via the Cardington large scale modeling experimental model (BFD) , and the effects of the height/width ratio and the effective opening width on the fire process are analyzed.Based on the simulated results , a model describing the unsteady heat transfer of frame structure is then established according to the heat transfer between the smoke and the frame structure. Moreover , a method to calculate the temperature field in the building component center is proposed by means of the finite differential method as well as by considering the interface joining condition. Finally ，The temperature field variations of two kinds of frame structures with the height and the time are calculated , in which the time step , the full calculation time , the fire growth coefficient t_g and the fire decay coefficient t_d are selected respectively as 1 s , 50min , 150s and 600s , and the fire experiences all the fire period including the growth , the flashover , the full development and the decay stages. The simulated temperature fields of the reinforced concrete and air-entrained concrete components basically accord with the experimental ones.

Key words: fire, frame structure, temperature field, dynamic characteristic, finite differential