This study presents a sequential numerical framework to evaluate the fire- resistance performance of earthquake-damaged structures under fire-following earthquake conditions. A nonlinear seismic analysis is conducted to determine the post-earthquake damage states of the structure, including residual deformation and stress redistribution. Subsequently, a thermal stress analysis is performed by directly transferring the damaged structural state as an initial condition for the realistic assessment of structural behavior under fire exposure. The numerical results are utilized to investigate the degradation in fire resistance caused by prior seismic damage; a fragility analysis is conducted to quantify the probability of exceeding fire-resistance limit states. The results confirm that earthquake-induced damage significantly reduce the fire resistance performance of the structures, even under identical fire exposure conditions. The fire resistance of protected steel structures may be overestimated if seismic damage is not considered.
Hee-Du Lee (Thu,) studied this question.