Grating weight: welded and pressed

Grating is a type of flooring, consisting of metal strips, interconnected in the form of a lattice. It can be made in two ways: welding or pressing. Depending on the manufacturing method, The weight of the resulting product may vary significantly.

The weight of the deck is important for calculating the load on the structure, on which it is installed. It also affects the cost of transportation and installation.. Therefore, knowledge of this parameter is necessary for designers, builders, customers and suppliers of this type of flooring.

The weight of this building material is a very necessary parameter, which affects its characteristics, such as strength, load, corrosion resistance, etc.. It depends on the size, strip thickness, distance between them and material, from which the flooring is made. Usually the mass is indicated in kilograms per square meter (kg/m2) or pounds per square foot (lb/ft2).

Why do you need to know the weight?

Knowledge of weight characteristics may be needed by people of different professions, who use or install such covering. For example, engineers and architects need to take into account the volume and mass of the deck when designing structures, on which he will lie, to ensure their reliability and safety. Builders and installers need to know this material characteristic for the correct selection of equipment and transport for its transportation and installation. Operators and maintenance personnel need to know the weight of the pavement to monitor its condition and carry out repairs if necessary..

Welded grating is made by welding cross strips to the load-bearing. Has high strength and rigidity, but also more weight compared to pressed grating. Its mass depends on the thickness and width of the strips, and also on the size of the lattice cells.

Extruded grating is made by pressing cross strips into load-bearing frames without welding.. Has less strength and rigidity, but also lighter weight compared to welded. Its mass depends on the same characteristics, as well as welded.

For that, to determine the weight of the coating, it is necessary to know the area and specific gravity of the material, from which it is made. The specific gravity of a material is the ratio of the mass of a unit volume of a material to the volume of this unit. For example, for steel this parameter is equal 7850 kg/m3, and for aluminum it is equal 2700 kg/m3.

The weight of the flooring can be calculated using several formulas. Next we will talk in detail about several types of calculation formulas.

Formula #1

W=S×T×B×G

Where:

• W – weight in kilograms;
• S – area in square meters;
• T – strip thickness in millimeters;
• B – its width in millimeters;
• G – specific gravity of the material in kilograms per cubic meter.

Example: Let's calculate the weight of a welded steel deck with a cell size 30 p 30 mm, strip thickness 3 mm and width 20 mm. Let the area be 10 m2.

W=10×0.003×0.02×7850=47.1 kg

Formula #2 – with duty cycle

The weight of the pressed grating can be calculated using a similar formula, but taking into account the grating filling factor K, which depends on the shape of the cells. The grating filling factor is the ratio of the strip area to the grating area. For example, for pressed flooring with strip sizes 25×2 mm, the distance between them 30 mm and rib section 10×2 mm, the fill factor is:

K=1000×1000L×T×D+S×R​

where K is the fill factor in fractions of unity, L – strip length in mm, T – its thickness in mm, D – their density (quantity of 1 m), S – rib cross-sectional area in mm2, R – edge density (number of ribs per 1 m).

Substituting values, we get:

K=1000×100025×2×33.33+20×33.33​=0.0499

It means, that the stripes take up about 5% lattice area, and the rest 95% - this is free space.

Fill factor affects light transmission, ventilation, drainage and aesthetics of grating. The higher the fill factor, the more light and air passes through the flooring, but the less water and dirt flows from it. Also, a high fill factor makes the flooring more massive and heavy., which may be undesirable for some applications.

Depending on the purpose and conditions of use of the lattice covering, you can choose different types and sizes of strips and ribs, to get the required fill factor. Typically, the grating fill factor ranges from 0.03 to 0.15.

In the next part of the article we will look at other flooring options, such as height, step, shape and material.

Formula #3

To calculate the weight of the flooring, you can use this formula::

• For welded:

W=1000L×B×T×D×7.85​

where W is the weight of the flooring in kg/m2, L – strip length in mm, B – its width in mm, T – its thickness in mm, D – their density (quantity of 1 m), 7.85 – steel density in g/cm3.

• For pressed:

W=1000L×B×T×D×7.85​+1000S×R×7.85​

where W is the weight of the flooring in kg/m2, L – strip length in mm, B – its width in mm, T – its thickness in mm, D – their density (quantity of 1 m), 7.85 – steel density in g/cm3, S – rib cross-sectional area in mm2, R – edge density (number of ribs per 1 m).

Examples of weight indicators for different types of lattice coverings:

• Welded with strip sizes 25×3 mm and the distance between them 30 mm has weight 12.5 kg/m2.
• Pressed with strip sizes 25×2 mm, the distance between them 30 mm and rib section 10×2 mm has weight 13.8 kg/m2.

In custody, we can say, that the weight of the grating depends on many factors, and it must be taken into account when choosing, purchase, installation and operation of such coverage. This parameter can be calculated using the formulas, above, or look in special tables, provided by manufacturers.

Table from the manufacturer PromNastil