# How to find out the quantity of concrete in a semi sphere slab In this exclusive civil engineering tutorial, you will get some useful tips to work out the quantity of materials for a spherical dome slab.

A dome stands for an architectural component and rounded vault that constructs the roof of a building or structure, generally with a circular base.

The spherical dome is created with a flat cut in a sphere.

The calculation is made based on the following dimensions :-

Exterior diameter = 16 feet
Exterior radius of semi sphere = 8.5 feet
Internal radius of semi sphere = 8 feet
Height is also taken as 8 feet
The thickness of the slab = 6 inches or 0.5 feet

To work out the volume of semi sphere, the following formula is used :-

= 2/3 x π x (R – r)2 x Height

After putting the values, we get the following :-

= 2/3 x 3.142 x [(8.5)2 – (8)2] x 8 = 138.24 cft

So, the required concrete of the dome slab = 138.24

The formula for determining the area of semi sphere is as follow :-

3 x π x (Radius)2

To get more details, go through the following video tutorial.

Video Source: Civil Study