Circular Slab

Introduction

• Uses of Circular Slabs:1.Roof of a room or hall circular in plan2.Floor of circular water tanks or towers3.Roof of pump houses constructed above tube

wells4.Roof of a traffic control post at the

intersection of roads

• 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.

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.

Simply supported slab with, uniformly distributed load

Simply supported slab with, uniformly distributed load

Fully restraint slab with uniformly distributed load

Fully restraint slab with uniformly distributed load

Simply supported slab with concentric load

Simply supported slab with concentric load

Simply supported slab with uniformly distributed load inside a concentric circle

Simply supported slab with uniformly distributed load inside a concentric circle

Simply supported slab with a circular hole and with uniformly distributed load

Simply supported slab with a circular hole and with uniformly distributed load

Simply supported slab with a circular hole and with concentric load

Simply supported slab with a circular hole and with concentric load

Simply supported slab with a circular hole and linearly varying distributed load

Simply supported slab with a circular hole and linearly varying distributed load

Simply supported slab with a circular hole and linearly varying distributed load