Friends to day I am going to teach you that how to calculate quantity of steel in slab. Most of people bring more steel which waste. Now in this post I will give complete guide that how can you calculate quantity of steel in slab. This process is for every type of slab. Slab consists of two type of steel which is called main bars & distributor bars. These bars are using in a proper quantity in slab. Main bars lying below form distributor bars. I mean first lay main bar and then laying distributor bars. Now how can you find the quantity of these bars (main bars & distruster bars)? This in not difficult method. But remember when you laying the steel in slab keep the clear cover (c.c) up to 3 inches of each side. Clear cover will protect your steel from corrosion this is very must for a slab or any type of R.C.C structure. Keep the bars away from the edges of the walls. I mean keep the steel at the center of walls.

Now you can find number of steel by the help of this formula.

No.Steel (Total Span)/(C.C distance)
No. of Main Bars =   Total Span/C.C distance
No. of Distributor Bars = Total Span /C.C distance

Where
Total Span: the distance between two walls is called span.
No. Steel: the number of steel which is using in slab.
C.C distance: the distance between two bars is called center to center distance (c.c distance). You can keep any c.c distance according to span. If the span is less then you can keep up to 9 inches but if the span is more then you will keep the c.c distance 6”-7”.
After finding the number of main bars and distribute bars. Now you can find the weight of steel with the help of below formula.
Weight Steel= (dia square)/52.92

Example of finding steel in slab

If a room is 16’ width and 14’ breathe. Then find or calculate steel quantity in this room.

Given data:
Width of the room = 16 ft
Breathe of the room =14 ft
Center/Center distance = 6 inch (0.5’)
Clear Cover = 3”
Steel dia = @ 4 suter ½”

Solution:
As you know that always short span of the room is using for Main Bars = 14’
And long span is using for laying distributer bars =16’
Now find first Main bars.
No. of Main Bars =   Total Span/C.C distance
No. of Main Bars = 14/0.5 =28 Number of steel
Now find number of distributor bars:
No. of Distributor Bars =   Total Span/C.C distance
No. of Distributor Bars = 16/0.5 =32 Number of steel.

Now find the length of one Main Bar =
14’-3”+3” = 14’ -0.5 = 13.5’

Now find of the unit weigh of bars in Kilo gram (Kg)
With the help of this formula
Weight Steel= (dia)2/52.92
Weight of steel = (4)2/52.92 = 0.302
Now we have one main bar length = 13.5’
13.5 * 0.302 = 4.081 Kg
Now we find one steel weight = 4.084 kg
One steel weight * Total number of main bars
4.084 * 28 = 114.352 Kg.
Now find the Length of one Distributor bar Remove Clear cover =
16’ – 3”+3” =16’ – 0.5’ (6”) =15.5’
Now find Unit weight of steel in Kg with the help of this formula:
Weight Steel= (dia square)/52.92
Weight steel = (4)2/52.92 =0.30
Length of one distributor bar * Unit weight of Steel
15.5 * 0.30= 4.65 Kg
Now find all disturber steel weight =

Formula is:
Weight of one distributor bar * Total distributor bars
4.65 * 32 = 148.8 Kg.
Now you have found the weight of Main bars and Distributor. Add it you will find total steel in Kg.
148.8+114.352 = 263.152 Kg