How quickly will steel lose structural strength from a heat flash?

I want to know if a sustained jet fuel burn around steel has the ability to make the steel structurally unsound. It seems like any applied heat that effects steel will be a kind of "heat flash": a sudden, and possibly quite short-lived, burst of heat. In this situation, we assume steel has a melting point of $\mathrm{2750\ ^\circ F\ (1510\ ^\circ C)}$ and that jet fuel (the source of the heat burst) burns at a maximum of $\mathrm{1500\ ^\circ F\ (\approx 816\ ^\circ C)}$. 


Some factors I believe need to be taken into place include the strength of bonds in steel, the thickness of the steel in question, and the distance from the heat source. Is a sudden heat flash enough to cause steel to weaken? Are there any other factors that need to be taken into consideration? 


