Following Are The Steps To Calculate The Quantity Of Steel For RCC Slab:
1- Prepare a bar bending schedule in order to classify different shapes of bars (bent up bar, straight anchor bar, eos bar, curtail bar, etc) and diameters.
2- List down all the shapes of bars from the drawing.
3- Count the number of bars of each of those shapes.
4- Then calculate the cutting length of each of those bars.
Cutting length of bar = (length of the member – deduction for cover on both sides) + development length.
5- Then calculate the unit weight of each dia bars by the following formula:
W = D^2/162*L
Where D is the diameter in mm and weight (w) in kg, L= total length m
6- Then calculate the weight of rebar
Weight of rebar= no of bars x cutting length x unit weight
7. Add all the weight to get the total steel quantity.
1- Minimum % Of Steel Are:
1- For Beam (Tension reinforcement):
As = 0.85bd/fy of gross cross-section area.
2- For Slab = 0.12% of total area
3- For Column = 0.8% of cs area
2- Maximum % Of Steel Are:
1- For Beam = 4 % of cross-section area.
2- For Slab = 4% of cross-section area.
3- For column = 6% of cross-section area.
3– Development Length is usually specified in the drawings, but if not then you can calculate it as,
D.L = Depth – 2 times cover
4– Binding wire = 10 grams per kg of reinforcement.
5- No. of stirrups = (length of member – 2 x cover ) / spacing + 1