## Quantity survey – Materials estimation for circular RCC water tank

In this illustration we will calculate cement, sand, crushed stone and of course steel for given water tank.

RCC has 1:2:4 with 15 cm thickness

PCC has 1:2:4 with thickness equal to 10 cm

The slab is RCC having 1:2:4 with 10 cm thickness

And of course there is a hole and the hole is circular with diameter = 60 cm

The depth is equal to 3 cm

The steel is 1% and #4 bar will be used

Solution:

Diameter = 4 meter + 2(15 cm) + 2 (10 cm) = 4.5 m = external circle diameter

PCC work = πD2/4 * T = π (4.5)2/4 * 0.1 = 1.59 m3

Assume the base or floor as S1 and wall as S2

D2 = 4 meter + 2(15 cm) = 4.3 m

The next approach is the RCC work in wall S1 = π (D1)2/4 * T = π (4.3)2/4 * 0.15 = 2.178 m3

RCC work in wall S2 = π ((D1)2 – (D)2)/4 * d = π ((4.3)2 – (4)2)/4 * 3 = 5.867 m3

RCC work in slab = π (4.3)2/4 * 0.1 = 1.452 m3

Deduction for hole = π (0.6)2/4 * 0.1 = 0.0282 m3

RCC work in Slab – Deduction for hole = 1.423 m3 = net quantity of RCC slab

Total RCC work = 2.178 m3 + 5.867 m3 + 1.452 m3 + 1.423 m3 = 9.468 m3

Steel = 1/100 * 9.468 = 0.09468 m3 * 7850 kg/cu.m (is the unit weight of density of mild steel) = 744 kg

Total net RCC = 9.468 m3 – 0.09468 m3 = 9.373 m3

Total PCC work (1:2:4) = 1.59 m3 + 9.373 m3 = 10.963 m3

Let’s calculate cement, sand and crushed stone work

Material = ratio of material/sum of ratio * dry volume

Ratio is 1:2:4 and sum of ratio is 7

Dry volume = wet volume * 1.54

Wet volume = 20*12*0.5

Wet volume = 120 CFT

Dry volume = 120 * 1.54

Dry volume = 184.8 CFT

Cement = 1/7 * 184.8 =26.4 CFT

Cement = 26.4/1.24 = 21.12 bags

Sand = 26.4 * 2 = 52.8 cft/100 = 0.528 sacra

Bajri = 26.4 * 4 = 105.6cft/100 = 1.056 sacra

Crushed stone = 6/10 * 770 = 462 CFT

Bajri = 462/100 = 4.62 sacra

To learn the complete process, watch the following online video demonstration.

Source