HOW TO CALCULATE STEEL QUANTITY FOR RCC BEAM, COLUMN AND SLAB

Following are the steps to calculate the quantity of steel for RCC slab:

• Prepare a bar bending schedule in order to classify different shapes of bars (bent up bar, straight anchor bar, curtail bar etc) and diameters.
• List down all the shapes of bars from the drawing.
• Count the number of bars of each of those shapes.
• Then calculate the cutting length of each of those bars.                                                          

Cutting length of bar = (length of member - deduction for cover on both sides) + development length.

• Then calculate the unit weight of each dia bars by the following formula:

W = d² / 162.
where, 
d is the dia in mm 
w is the weight in kg.

• Then calculate the weight of rebar

Weight of rebar = no. of bars x cutting length x unit weight

• Add all the weight to get the total steel quantity.

NOTE: 
   
    1. Minimum % of steel as per Indian standards are:

• Beam (Tension reinforcement): 

As = 0.85 bd/fy of gross section area.

• Slab - 0.12% of total area
• Column - 0.8% of total area.

    2. Maximum % steel as per Indian standard are:

• Beam - 4% of cross-section area
• Slab - 4% of cross-section area
• 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.