The dependence of the mass of reinforcement on the density of steel is obvious, but to simplify the calculations there are also correspondence tables. So that you do not have difficulties when calculating this expensive material, let's figure out how much it needs to be used in construction. In the construction of monolithic reinforced concrete structures , steel reinforcement is used, the weight of a running meter of which may be different due to the unequal thickness of the metal rods. Consider how to gradually control their consumption.
How to find out the volume of reinforcement?
In the drawings and diagrams of steel frames and grids, designers indicate the weight and length of each assembly element and ultimately reduce the cost of materials in the calculation. They also rely on these design values when drawing up budget documentation, and when fittings are purchased by contractors, the weight of a running meter does not change due to humidity, corrosion or other technical conditions. All these errors are already taken into account to the maximum in tabular values. For example, according to the table, the weight of a running meter of reinforcement 10 mm is 0.617 kg, but slight inaccuracies are possible - per ton, according to the norms, they should be no more than ± 5-6%. But these figures suggest a combination of the most unfavorable circumstances, therefore they try to prevent deviations by more than ± 2-3% and to prevent possible speculation.
Hot rolled fittings. Weight per meter of material.
Rod Cross Section Size | Weight 1 m. | Rebar length in ton | Boundary deviations of weight |
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% |
Calculation of the number of fittings in 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, such a condition:
reinforcement 12, the linear meter weight is unknown, but its length in all frames is 100 m. We calculate the area of a circle with a radius of 6 mm, multiply by the height (i.e. the length of the rods) and the density of the material from which they are made. The ribbing of the reinforcement during the calculations is neglected. As a result, we obtain: πR
2 × 100 × ρ
STEEL = 3.14 × 0.006
2 × 100 × 7850 = 88.74 kg. After checking the table, we will verify the correctness of the calculation. At 100 meters of material, the deviation was only 0.06 kg, which easily fits into the maximum
measurement error of ± 3%.
Control of material consumption at the construction site
In any business, including such as the sale of rolled metal products, everyone knows each other perfectly, so it’s better to ask the construction supervisor in your city about the decency of the sellers in your city, who will supervise the work on the construction site. This specialist knows thoroughly where and why steel reinforcement is used, the weight of a running meter of this structural material will also not be news to him. Therefore, do not forget to remind him to collect all receipts and invoices for metal rolling. After all, armed with drawings showing the length of the reinforcement of each
welded wire mesh and frame, you can jointly conduct a fascinating tour of the building under construction and make sure that something rolled in the process, or just make sure that the materials are used optimally. The result of such mutually beneficial cooperation will be a perfectly completed structure and your mutual satisfaction.