Under fire conditions

the concrete slab in steel frames can be forced into large deformation

resulting in the formation of large individual cracks within floor slabs.These localized cracks may expose steel reinforcement directly to fire and damage the membrane action of slab

thus significantly reducing the fire resistance of the buildings.This paper presents a robust finite element procedure for predicting both global response（deformation and fire resistance）and localized failure（localized individual cracks）of concrete slab at elevated temperatures

which uses extended finite element method to capture the localized cracks within reinforced concrete floor slabs.The new model has been validated against previous fire test results.It is evident that the nonlinear procedure proposed in this paper can effectively capture the propagation of individual cracks and predict the opening of cracks

thus providing engineers a tool for assessing both the global response and the integrity failure of the floor slabs in fire.