Unit weight of steel bars – How to calculate?

Calculating the unit weight of steel bars with various diameters is crucial when creating a schedule for bar bending. The total weight of steel bars/TMT bars weight required for the project’s construction can be calculated once we know the unit weight of steel.

Steel is the most commonly used structural material. Steel’s basic components include metallic iron, non-metallic carbon, and minor amounts of nickel, silicon, manganese, chromium, and copper, among others. High tensile strength makes it a popular construction material for civil engineering projects. Steel reinforcement bars, often known as rebar, are placed in concrete members to enhance their tensile strength. As we all know, steel is utilised to construct structural members such as columns, beams, footings, foundations, and building slabs. Steel bars of various sizes are supplied by the manufacturer, with lengths of 12 metres or 40 feet.

1. Why Unit Weight of steel bars Calculation is Important?
2. How to calculate the steel bar weight/ TMT bars weight?
3. Calculation of weight of steel bars per Running Meter
   1. Weight of steel per Meter
   2. Weight of steel per foot
   3. Weight of steel bars/TMT bars weight per meter

Why Unit Weight of steel bars Calculation is Important?

It is essential to comprehend the weight of steel bars since we estimate them as 100 metres 20 mm bar, 100 feet 16mm bar, and so on (is the sign for diameter). Steel bar manufacturers, on the other hand, will not interpret this notation and will measure the steel bars in weight. So we have to order them in kilogrammes, quintals, or tonnes. This article will go through how to use the steel weight formula to determine the steel bar’s weight.

How to calculate the steel bar weight/ TMT bars weight?

Steel bar unit weight is the weight of steel per unit volume. Its SI unit is kg/m3. The unit weight of steel is typically measured as follows

• Kilogrammes per cubic metre (7850 kg/m3),
• Kilo Newton per cubic metre (78.5 kN/m3),
• Grams per cubic centimetre (7.85 g/cm3).

Calculation of weight of steel bars per Running Meter

Let’s start with a 12 mm diameter.

The length of the rod L = 1 meter.

Steel has a density of 7850 kg/m3.

Let us see how the formula calculates the weight of steel bars.

Area of steel rod (Circular shape) = πr² or πD²/4

Hence the wt of steel bar formula

= Area of steel x Density of steel x Length of steel

Where

Area of steel = πD²/4

The density of steel = 7850 kg / m³

Length of steel = 1 mtr

Diameter of steel = D mm

Weight of steel per Meter

= πD²/4 x 7850 x 1m = 3.14 x (D² / 4) x 7850 x 1m

In this equation,

the Diameter is in mm and the Density (Unit Weight) is in m³

Let us convert the Diameter in mm² to m as below

1 mm = 1/1000 m , 1 mm² = 1/(1000)² mm²

= 3.14 x (D² /4 ) X 1/(1000) ² X 7850 X 1

Weight of steel bars formula= D² x 6162.5 x 1/(1000)²

= D² x 1/(0.006162)^-1

= D2 / 162.28

For calculation purposes, we used to take D²/162

Weight of steel rod per Running meter = D2/162 where D is the diameter of steel rod in mm

For a 12 mm dia rod,

D = 12 mm

Weight per meter = 12 x 12 /162 = 0.889 kg per rmt or meter length or unit length

If you want to know the steel weight per foot. 1 metre = 3.281 ft. Just multiply the same.

Weight of steel per foot

1 metre = 3.281 ft. Just multiply the same.

= D2/162 x 3.281 = D² / 533

Weight of steel bars/TMT bars weight per meter

Let us have an idea about the unit weight of common diameters of reinforcement steel used in civil engineering construction.