722.2.2 Concrete Floor and Roof Slabs
|CONCRETE TYPE||FIRE-RESISTANCE RATING (hours)|
The thickness of slabs with sloping soffits (see Figure 7220.127.116.11.2) shall be determined at a distance 2t or 6 inches (152 mm), whichever is less, from the point of minimum thickness, where t is the minimum thickness.
The thickness of slabs with ribbed or undulating soffits (see Figure 718.104.22.168.3) shall be determined by one of the following expressions, whichever is applicable:
For s > 4t, the thickness to be used shall be t
For s ≤ 2t, the thickness to be used shall be te
For 4t > s > 2t, the thickness to be used shall be
s = Spacing of ribs or undulations.
t = Minimum thickness.
te = Equivalent thickness of the slab calculated as the net area of the slab divided by the width, in which the maximum thickness used in the calculation shall not exceed 2t.