REINFORCEMENT OR BAR WEIGHT CALCULATION

REINFORCEMENT OR BAR WEIGHT CALCULATION

This is the era of Reinforced Cement Concrete structure. Reinforcement or Bars are used in Concrete Structure to provide extra strength in Structure. Ordinary Cement concrete is good for withstanding Compressive stress but fails in Tensile stress. To withstand this tensile stress we embedded Reinforcement or Bar in Ordinary Cement concrete. This type of concrete is called Reinforced Cement Concrete.

Reinforcements are made of steel (not pure) with round shaped with specific diameter with ribs in body. We identify or named reinforcements with their specific diameter (i.e.8mm bar/10mm bar etc).

As per IS- 1786.2008 Nominal Size or specific diameter of bars are 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 28mm, 32mm, 36mm & 40mm . We use this bar as pre design specification. Naturally length of a single bar is 12-13m.

But our motive is to calculate the weight of bar per meter length.

Calculation

We know density of steel is – 7850 kg/m³

A basic formula we all know is Density = Mass /Volume.

So, Mass = Density x Volume.

Next step, find the volume of bar, we know Volume = Cross Sectional Area x Length

Here we find weight for 1m length.

So, Volume = π/4 D² x 1 m³

Mass = Density x Volume.

Mass = 7850 x π/4 D² x 1 kg

In the above formula we put the value of D (diameter) in meter and get the weight of bar per meter length

For example, Weight of 10mm dia bar per meter length

D = 10 mm or 0.01 m

So,          Mass     = 7850 x π/4 D² x 1 kg

                                = (7850 x 3.14 x 0.01 x 0.01 x 1 )/4 kg

                                = 0.616 kg

Otherways

Another tricky calculation is derived from above equation which is vastly used in construction field is   D²/162.28

Where the value of D is consider in mm.

Let’s check the same example above, Weight of 10mm dia bar per meter length

D =10mm now put the value in the formula D²/162.28

Mass = (10 x 10)/162.28 kg

= 0.616 kg