how can we determine the quantity of steel bars in a structure? is there any f

how can we determine the quantity of steel bars in a
structure? is there any formula for determing the number of
bars required ?

Question Posted / yasir shehzad

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how can we determine the quantity of steel bars in a structure? is there any formula for determing..

Answer / arastu

to calculate the weight of steel in field, we use:

W = (d*d/162) kg/m

where d= dia of bar in mm

this is formula u can drive from Density = (weight/volume)

density of steel = 7850kg/m3
volume of bar (1 m length) = 3.14/4*d*d*1

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how can we determine the quantity of steel bars in a structure? is there any formula for determing..

Answer / poovaraghavan

Reinforcement steels are available in various sizes from
8mm to 32mm dia. In order calculate the weight of those
reinforcement bars, there is a formula derived form the
unit weight of steel and the unit volume of the respective
steel bar. In this case you need to remember the unit
weight of steel and more over you need to make unit
conversions for the dia meter of the bar. Because commonly
the diameter of the reinforcement bar is mentioned in
millimeters and the unit weight of the steel (7850 kg/cu.m)
is mentioned in kg/cu.m.

Here, either you need to convert the dia of the bar to
meter or to convert the unit weight of steel to kg/cu.mm
(Kilogram / Cubic millimeter). To reduce this difficulty
and save our valuable time, here is a thumb rule. Also the
rule has been analised and proved here. you can check it
and use it.

Unit weight of the Bar = (Unit volume of the bar) * (Unit
weight of Steel)

= (3.14 * d * d /4) * 1 * (7850)
kg/m Where, d – in meters

= 6165.376 * d * d

= 0.00617
d^2
Where, d – in Millimeters

For a Thumb rule, we can write the above formula as 0.617 *
d^2 /100.

This will give you the weight of the bar in terms of kg/m.

In the above formula you just need to remember only 0.617
as a constant and you can substitute dia in Millimeter
itself. Finally don’t forget divide the answer by 100 as
described above.