Recent events of fire after an earthquake (FAE) show that this is a frequent dual event leading to a significant loss which can only be reduced by increasing the level of safety. This paper presents numerical models developed for FAE analyses on 24 steel portal frames to investigate their behaviour and estimate the performance in terms of ratios with regard to horizontal displacement, fire resistance time, and critical temperature. In this study, validated numerical models are used for a parametric study to explore the effect of number of bays and stories on the performance of steel frames under two fire scenarios. Frames with one bay and one story are designed with the Algerian seismic code, RPA99v2003, considering the seismic region of Chlef and other frames are checked with Eurocode for the ultimate limit state. All frames subjected to the
seismic and the ISO834 fire actions are simulated within a single software, ANSYS, for pushover and thermo-mechanical analyses. The performance is evaluated, by FAE analysis for damaged frames remaining in the plastic state and undamaged frames not reaching the plastic state, and compared to those subjected to fire without earthquake (FWoE). The frames under FAE are more vulnerable to fire and increasing damage is produced and hence reducing their structural performance. The results also show that the higher the number of bays is, the higher the performance of the frames. The critical temperature of beams decreases with the beam length. The frames with FAE, under inelastic conditions, have smaller fire resistance, when compared to undamaged frames.
