The dependence of the mass of the reinforcement on the density of steel is obvious, but to simplify the calculi there are also correspondence tables. So that you do not have difficulties in calculating this cheap material, let's figure out how much it should be used for construction. When building monolithic reinforced concrete structures, steel reinforcement is used, the weight of the running meter of which may be different due to the unequal thickness of the metal rods. Let's consider how to control their consumption step-by-step.
How to learn the volume of reinforcement?
In the drawings and diagrams of steel frames and nets, the designers indicate the weight and length of each assembly element and, as a result, reduce material costs in the calculation. These design values are also used in the preparation of estimate documentation, and when contractors purchase reinforcement, the weight of the running meter does not change from humidity, corrosion or other technical conditions. All these errors are already taken into account in the tabular values. For example, according to the table, the weight of the running meter of the reinforcement is 10 mm equal to 0.617 kg, but there may be slight inaccuracies - they should not exceed ± 5-6% per ton. But these figures suggest the confluence of the most unfavorable circumstances, so try not to allow deviations of more than ± 2-3% and prevent possible speculation.
Hot rolled reinforcement. Weight per meter of material.
Size of cross-section of rods
| Weight 1 m.
| Length of reinforcement in ton
| Boundary weight deviations
|
Ø6
| 0.222 kg
| 4504.5 m
| ± 7-9%
|
Ø8
| 0.395 kg
| 2531.65 m
|
± 7-9%
|
Ø10
| 0.617 kg
| 1620.75 m
| ± 5-6%
|
Ø12
| 0.888 kg
| 1126.13 m
| ± 5-6%
|
Ø14
| 1.21 kg
| 826.45 m
| ± 5-6%
|
Ø16
| 1.58 kg
| 632.91 m
| ± 3-5%
|
Ø18
| 2 kg
| 500 m
| ± 3-5%
|
Ø20
| 2.47 kg
| 404.86 m
| ± 3-5%
|
Ø22
| 2.98 kg
| 335.57 m
| ± 3-5%
|
Ø25
| 3.85 kg
| 259.74 m
| ± 3-5%
|
Ø28
| 4.83 kg
| 207.04 m
| ± 3-5%
|
Ø32
| 6.31 kg
| 158.48 m
| ± 3-4%
|
Ø36
| 7.99 kg
| 125.16 m
| ± 3-4%
|
Ø40
| 9.87 kg
| 101.32 m
| ± 3-4%
|
Counting the number of reinforcement after the fact
You can easily calculate the weight of the reinforcement, relying only on the length and diameter of the rods, since the density of steel is well known and is 7850 kg / m 3 . For example, this condition: armature 12, the weight of the running meter is unknown, but its length in all frames is 100 m. Calculate the area of the circle with a radius of 6 mm, multiply by the height (that is, the length of the rods) and the density of the material from which they are made. The ribbing of the armature is neglected in the calculations. As a result we obtain: πR 2 × 100 × ρ STEEL = 3.14 × 0.006 2 × 100 × 7850 = 88.74 kg. Checking the table, we will see the correctness of the calculation. At 100 meters of the material, the deviation was only 0.06 kg, which easily fits into the maximum measurement error of ± 3%.
Monitoring of materials consumption at the construction site
In any business, including such as the sale of rolled metal, everyone knows each other perfectly, accordingly, the decency of sellers in your city is better to ask the foreman who will supervise the execution of work on the construction site. This specialist thoroughly knows where and why steel bars are used, the weight of the running meter of this constructive material will not be new to him, either. So do not forget to remind him to collect all checks and bills for metal. After armed with the drawings, which indicate the length of the armature of each welded wire mesh and frame, you can jointly conduct an exciting tour of the erected building and make sure that you have not rolled something in the process, or just make sure of the optimal use of materials. The result of such mutually beneficial cooperation will be a perfectly executed structure and your mutual satisfaction.