Hollow columns are used in structures where internal temperature of the structure is more than surrounding temperature or is variable .due to such kind of variation in temperature the reinforcement used in structure undergoes freezing and thawing reaction which leads to failure of the structure, hence to avoid such kind of situation hollow columns are provided. the mechanism of hollow column works like when the temperature increases the temperature of the air inside the column increases and the air expands and also vice versa leading to make reinforcement unaffected.

**How To Calculate Volume Of Hollow Column?**

Given

h = 3.5 m

R = 0.8 m

r = 0.4 m

**Where**

h = Height of the hollow column.

R = Centre to the outer radius of the hollow column.

r = Centre to the internal radius of the hollow column.

The formula for calculating the volume of hollow column is given below:

**Volume** = (πR²h – πr²h)

= πh ( R² – r²)

= 3.14 x 3.5( 0.8² – 0.4²) [∵ π =3.14]

= 10.99 ( 0.64 – 0.16)

= 10.99 x 0.48

= **5.27 m³**