Q. Concrete cover to enhance fire resistance?

In the event of exposing concrete structures to a fire, a temperature gradient is established across the cross section of concrete structures. For shallow covers, steel reinforcement inside structures rises in temperature. In general speaking, steel loses about half of its strength when temperature rises to about 550^oC. Gradually steel loses strength and this leads to considerable deflections and even structural failure in worst scenario. Therefore adequate cover must be provided for reinforced concrete structure as a means to delay rise in temperature in steel reinforcement.