Now we are going to learn how to create bbs of a slab, we have previously learnt the bbs of column, footing and beam. We are going to use all the formulae we learnt in the basics of bbs.
![BBS of a Slab Bar Bending Schedule Tutorial 1 slab drawing](https://theindusdeveloper.com/wp-content/uploads/2023/03/slab-drawing-1024x831.png)
As you can see from the drawing above there are two kinds of bars in this slab. One bar along the main x direction and another one along the y direction. It might seem that we have 4 bars but if you look carefully the black and red bars are actually the same bar but in the opposite direction.
So lets start with the Main X bars
Length of rebar
Slab has a width of 4 m
There is cover of 25mm on each side = 25mm+25mm= 50mm = 0.05m
Effective Slab length = slab width – cover = 4m – 0.05m = 3.95m
Bar Length = Slab length + inclined length
D = Slab Height – cover = 150 – (25 +25) = 100mm
Inclined length = 0.42*D
= 0.42*100= 42mm
Total Length of Main X bar = Effective Slab length + inclined length
= 3.95 + 0.042= 3.992m
Bend Deduction
As we already have learned in the basic of bar bending schedule that for every 45 degree bend we apply a deduction equal to d( 1 times diameter)
Here we have two 45 degree bend so we must apply a deduction of d+d to the total length of the bar
Deduction = 12 +12=24mm = 0.024m
Effective Length = Total Length – Deduction
= 3.992 – 0.024
= 3.968m
Number of bars
No of bars = Distance/spacing + 1
Distance = Slab length – cover = 3.95m
Spacing = 120mm
No of Bars = 3950/120 +1
= 33+1
= 34
Unit Weight
We know that Unit weight of any bar = d2/162
Here out diameter= 12mm
Unit weicht = 12*12/162 = 0.89 kg/m
Total Weight
Total weight = Length*number*Unit Weight
= 3.968 * 33* 0.89
= 116.54 Kg
Main x rebar
![BBS of a Slab Bar Bending Schedule Tutorial 2 main x slab reabar](https://theindusdeveloper.com/wp-content/uploads/2023/03/main-x-slab-reabar-1024x174.png)
Main Y rebar
Length of rebar
Slab has a width of 5 m
There is cover of 25mm on each side = 25mm+25mm= 50mm = 0.05m
Effective Slab length = slab width – cover = 5m – 0.05m = 4.95m
Bar Length = Slab length + inclined length
D = Slab Height – cover = 150 – (25 +25) = 100mm
Inclined length = 0.42*D
= 0.42*100= 42mm
Total Length of Main X bar = Effective Slab length + inclined length
= 3.95 + 0.042= 4.992m
Bend Deduction
As we already have learned in the basic of bar bending schedule that for every 45 degree bend we apply a deduction equal to d( 1 times diameter)
Here we have two 45 degree bend so we must apply a deduction of d+d to the total length of the bar
Deduction = 8 +8=16mm = 0.016m
Effective Length = Total Length – Deduction
= 4.992 – 0.016
= 4.976m
Number of bars
No of bars = Distance/spacing + 1
Distance = Slab length – cover = 4.95m
Spacing = 120mm
No of Bars = 4950/120 +1
= 41+1
= 42
Unit weight
Unit weight of any rebar = d2/162
= 8*8/162
= 0.395 Kg/m
Total Weight
Total weight =Length*number*Unit Weight
= 4.976 * 42* 0.395
= 82.55 Kg
![BBS of a Slab Bar Bending Schedule Tutorial 3 main y rebar bbs](https://theindusdeveloper.com/wp-content/uploads/2023/03/main-y-rebar-bbs-1024x173.png)
So here is the full bbs of Slab
![BBS of a Slab Bar Bending Schedule Tutorial 4 bbs of slab](https://theindusdeveloper.com/wp-content/uploads/2023/03/bbs-of-slab-1024x346.png)
If you want a free software to make bar bending schedule I highly recommend you download the official BBS app
BBS App Android Google Play Link: Click here to download
iPhone AppStore Line: Click here to download
If you are a fresher civil engineer and want to know how to get a job read this article: How to get a job as a fresher civil engineer.