How to find the weight of the steel/reinforcement or rebar and steel weight formula derivation.
To find the reinforcement weight using a formula.
d2/162 -for per meter. (d2/162) x L -for the total length
d = diameter of the steel, L = required length
For example;
the diameter of the steel is 8mm and the length is 12m. What is the weight of this steel?
solve,
d = 8mm and L = 12m (if you want a weight of 10m length, then substitute 10 on L) = d2/162 = 8^2 / 162 = 0.4 kg/m = (d2/162) x L= (8^2/162) x 12 = 4.8 kg (for total length)
The maximum length of the steel is 11m or 12m is constant, maybe it differs from the manufacturer’s requirement
Derivation of the formula
d is the diameter of the steel, L is the length of the steel than what is that 162? let’s see the derivation and you know how 162 is comes
weight = volume x density
volume = (area x height)
= (( πd^2 / 4) x 1000mm) x 7850 kg/m3
= ((3.14/4)xd^2 x 1000) x (7850/10^8)kg/mm3
= 785xd2x7.85e-6
= d2 x 0.00616
= (d2/1) x (0.00616/1)
= (d2/162.29) ~ (d2/162)
= (d2/162) is per m
= ((d2/162) x L) is for required meter L is required meter or length
the derivation of the steel weight formula is asked in most of the interview
Weight of the reinforcements
Low and Medium strength steel
| The diameter of the bar (mm) | Weight per meter (kg/m) | Weight for the total length (kg) |
|---|---|---|
| 6 | 0.22 | 2.64 |
| 8 | 0.4 | 4.8 |
| 10 | 0.62 | 7.44 |
| 12 | 0.9 | 10.8 |
| 14 | 1.21 | 14.52 |
| 16 | 1.6 | 19.2 |
| 18 | 2 | 24 |
High strength steel
| The diameter of the bar (mm) | Weight per meter (kg/m) | Weight for the total length (kg) |
|---|---|---|
| 20 | 2.5 | 30 |
| 22 | 3 | 36 |
| 25 | 4 | 48 |
| 28 | 5 | 60 |
| 32 | 6.32 | 75.84 |
| 36 | 8 | 96 |
| 40 | 10 | 120 |
Steel weight calculator ” Click here ”
Note
- The quality of materials can change the theoretical weight of the reinforcement and the site conditions
- the unit weight or density of the steel is 7850 kg/m3