Calculate the Weight of Reinforcement Steel

Reinforcement steels are available in various sizes from 8mm to 32mm dia. In order calculate the weight of those reinforcement bars, there is a formula derived form the unit weight of steel and the unit volume of the respective steel bar. In this case you need to remember the unit weight of steel and more over you need to make unit conversions for the dia meter of the bar. Because commonly the diameter of the reinforcement bar is mentioned in millimeters and the unit weight of the steel (7850 kg/cu.m) is mentioned in kg/cu.m.

Here, either you need to convert the dia of the bar to meter or to convert the unit weight of steel to kg/cu.mm (Kilogram / Cubic millimeter). To reduce this difficulty and save our valuable time, here is a thumb rule. Also the rule has been analised and proved here. you can check it and use it.

Unit weight of the Bar = (Unit volume of the bar) * (Unit weight of Steel)

= (3.14 * d * d /4) * 1 * (7850) kg/m                         Where, d – in meters

= 6165.376 * d * d

= 0.00617 d^2                                                          Where, d – in Millimeters

For a Thumb rule, we can write the above formula as 0.617 * d^2 /100.

This will give you the weight of the bar in terms of kg/m.

In the above formula you just need to remember only 0.617 as a constant and you can substitute dia in Millimeter itself. Finally don’t forget divide the answer by 100 as described above.

Tagged as: Reinforcement Steel