1) Slab – 1% of the total volume of concrete
2) Beam – 2% of the total volume of concrete
3) Column – 2.5% of total volume of concrete
4) Footings – 0.8% of the total volume of concrete
For example, let us take RCC column with reinforcement requirement of 2.5 % of concrete volume then the weight of the steel required will be:
(2.5*7850)/(100*1) = 196.25 kg
https://ia800406.us.archive.org/1/items/gov.in.is.456.2000/is.456.2000.pdf pls download the code and go through for further details