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
Where d is the dia in mm and
weight (w) in kg.
6. Then calculate 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.
NOTE – 1. Minimum % of steel as per Indian standard
are:
1.
Beam (Teinsion reinforcement):
As
= 0.85bd/fy of gross cross-section area.
2.
Slab – 0.12% of total area
3.
Column – 0.8% of cs area
2.
Maximum % steel as per Indian standard are:
1. Beam – 4 % of
cross-section area.
2. Slab – 4%
of cross-section area.
3. column — 6% of
cross-section area.
3.
Development Length is usually
specified in the drawings, but if not thenyou 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
