The question should be framed thus: "How to calculate
quantity of steel for practical purpose of construction"....
"In a given RCC design" it is simple to arrive at the
quantity by calculating the lenght of each bar & multiply
with the unit weight of given dia.
The thumb rule for calculating steel quantity is 1.5 to 2.0
The quantity of steel can be calculated by formula:
d*d/162 kg/m. where d=diameter of bar in metre
this formula has been derived by relation
However, percentage of steel in rcc structure can be taken
as 0.15% of the gross area of cocrete