## Numerical on the analysis of Circular water tank

**Example 1**. Design a circular tank with flexible base for capacity of 500,000 litres.

**Sol**. Depth of 4 m, is provided with free board of 20 cm. If D is the diameter of the tank capacity of the tank will be

Provide diameter of 13 m.

Maximum hoop tension at base for one metre height

Area of steel required

Provide 16 mm φ bars at 7 cm centres.

**A _{t} = 28.73 cm^{2}**

Use mix M 200. Allowable stress in tension

**= 12 kg/cm ^{2}.
**

Let 't' be thickness of wall.

**= 21.67 – 3.448 = 25.118 cm**

Provide thickness of 26 cm.

Hoop reinforcement will be provided on both faces. 16 mm φ bars at 14 cm centres are provided on each face.

**Vertical reinforcement**

**= 0.26%**

Bending moment

**Loading intensity**

If the effect of the lateral restraint is taken into account modified flexural rigidity will be