The unit weight of any substance is defined as the ratio of mass or weight per unit volume. It is generally measured in pound/ft, gm/cm or, kg/cm or kg/m, etc.
The density of steel is around 7850 kg/m3 or 7.85 g/cm3 or 490 lbs/ft3 or 13231 lbs/yd3.
There are various steel diameters used in construction are –
8mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 32 mm, and 40 mm.
The steel diameter used for normal residential, commercial, and office building construction is 8 mm to 20 mm.
The steel diameter 25 mm to 40 mm is used for heavy construction like bridges, dams, and retaining walls.
The formula used to calculate the unit weight of steel bars is D²/162.
Where, D = Dia. Of steel bars
and 162 is a constant value.