It is important to calculate the unit weight of steel bars of different diameters for preparing bar bending schedule.
How To Calculate Weight Of Steel Bars:
After estimating, it is very important to know the unit weight of steel bars because we estimate them as 100 meters 20 mm ø bar, or 100 feet 16mm ø bar, etc (ø is the symbol of diameter). But steel bar suppliers will not understand this notation, and they measure the steel bars in weight.
So we have to order them in kg or quintal or ton. This article will discuss how to calculate the unit weight of steel bars of different diameters by using the steel weight formula.
Here is the steel weight formula W = D²L/162
- W = Weight of steel bars.
- D = Diameter of steel bars in mm.
- L = Length of bars in meter.
Example 1: Calculate the weight of 60 meters long 12 mm ø bar.
- D = 12 mm.
- L= 60 m.
We know that,
- W = D²L/162
W = 12² x 60/162 = 53 kg
- Weight of 60 m 12mm ø bar is 53 kg.
Let’s look for another example.
Example 2: Calculate the weight of 100 m 16 mm ø bar.
- D = 16 mm.
- L = 100 m.
W = 16² x 100/162 = 158 kg.
If we put 1 meter length for each diameter of steel bar in the formula then we will get the unit weight.
- 6 mm ø bar = 6² x 1/162 = 0.222 kg/m
- 8 mm ø bar = 8² x 1/162 = 0.395 kg/m
- 10mm ø bar = 10² x 1/162 = 0.617 kg/m
- 12mm ø bar = 12² x 1/162 = 0.888 kg/m
- 16mm ø bar = 16² x 1/162 = 1.580 kg/m
- 20mm ø bar = 20² x 1/162 = 2.469 kg/m
If we multiply the length of bars by this unit weight, we will get the total weight of steel bars. For example, the total weight of 1000 meter long 20mm ø steel bar is,
1000 x 2.469 = 2469 kg.
Using the same method we can calculate the unit weight of different steel bars. Here I have calculated in meter but we can also calculate in feet. To calculate in feet we have to use the following formula:
- W= D²L/533
- D = Diameter of bars in mm.
- L = Length of bars in foot.