2. Introduction
• Uses of Circular Slabs:
1.Roof of a room or hall circular in plan
2.Floor of circular water tanks or towers
3.Roof of pump houses constructed above tube
wells
4.Roof of a traffic control post at the
intersection of roads
3. • In circular slab, Bending takes place in
distinctly two perpendicular directions along
the two spans.
• Reinforcement is provided in the form of a
mesh of bars having equal area of cross
section in both the directions, the area being
equal to that required for the bigger of the
radial and circumferential moments.
• However, if the stresses near the edge are not
negligible, or if the edge is fixed, radial and
circumferential reinforcement near the edge
becomes essential.
4. Circular slab
• Circular slabs are more commonly used in the design of circular
water tank containers with flat bottom and raft foundations.
• The analysis of stresses in these slabs is generally based on elastic
theory. Under uniformly distributed loads, these slabs deflect in the
form of a saucer and develop radial and circumferential stresses.
Tensile stresses develop on the convex surface and compressive
stresses develop on the concave surface.
• Tensile stresses must be provided in the radial and circumferential
directions near the convex surface.
• Alternatively, reinforcing bars can be provided in two mutually
perpendicular directions instead of in the radial and circumferential
directions.
• Normally, near the Centre of the slab, reinforcement is provided in
the form of mutually right angle mesh; and near the edge of the
slab, in the form of radial and circumferential bars.