Fire Response of Reinforced Concrete Slabs

A mathematical procedure is described by which the structural response of reinforced concrete slabs in fire environments can be predicted. The procedure has been implemented in a computer program, FIRES-SL. An iterative approach is used within time steps to find a deformed shape at which external loads and internal stresses are in equilibrium. The solution method can be used for any specified slab shape, boundary conditions, and placement of reinforcement. Stresses in the direction normal to the slab surface are not considered. A state of biaxial plane stress for concrete and uniaxial stress for steel has been assumed in deriving the material behavior models. These models account for dimensional changes caused by temperature differentials, changes in the mechanical properties of materials with changes in temperature, increased rates of shrinkage and creep with an increase in temperature, and degradation of elements through cracking in different orientations, crushing, and yielding.