In calculations regarding concrete slabs, the effective
depth is important as it is used to calculate the required level of
reinforcement for an element of a certain thickness to resist a certain bending
The effective depth is
also used to find the critical punching perimeter and is used in the shear
capacity calculations. In this instance the effective depth of a slab with
fibre reinforcement or no reinforcement should be taken as 0.75h, where h is
the overall depth.