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1. Bar Bending Schedule [BBS] Estimate of Steel in Building Construction
Introduction to Bar Bending Schedule [BBS]:-
“BBS” The word BBS Plays a significant role in any construction of High rise buildings. BBS
refers to Bar Bending Schedule. Well, What’s the use of BBS? Why we use BBS? What is BBS?
In this internship, we are majorly focused on how and where to start and what are the basics. Apart
from this, you can also learn
First of all, Bar is any type of rebar which is used as a reinforcement in RCC. The bar may be a
Mild Steel bar or HYSD bar or TMT Bar.
Bar Bending Schedule is termed as “Calculation of the total Steel required for the construction of
a building” We use steel to make concrete to be reinforced and for tension requirements. But
how much steel required for constructing 15 floors building? How much Steel I have to order?
All these questions are answered in BBS
In Bar bending schedule, the bars are organized for each structural units (Beams or columns or
slabs or footings etc) and detailed list is prepared which specifies the Bar location (Bar in
footings, slabs, beams or columns), Bar Marking (to identify the bar in accordance with the
drawing), Bar Size (length of the bar used), Quantity (No. of Bars used), Cutting length, Type of
Bend and Shape of the bar in reinforcement drawings.
How BBS Changed from 1950-2019:-
From 1950 to 2019 lots of modifications and enhancements happening in our world. In 1950,
three-storeyed buildings are high rise buildings now we are constructing a building with 200
floors+. There is a massive growth in the construction industry. Due to the vast increase in world
population demands increased facilities, more need for space and more construction.
Father of Estimation B.N. Datta has given certain recommendations for the usage of steel in
different components of buildings. But, he didn’t mention any values if we use more bars in a
single structural member.

2. At that time we’ve used only four bars in columns; now we are using 12+ bars in columns based
on load analysis. So, the percentage of steel is increased in a column which reveals that the
above-cited values are outdated. ( They are outdated “not wrong”) He wrote that book in 1950.
Now we are in 2019. He gave recommendations according to the potentiality of construction at
that time. Now we are constructing 200 + floors in the small area.
Bar Bending Schedule [BBS]:-
Before dealing with the BBS, it’s very important to learn the basics of Bar bending schedule. The
below-mentioned table is a kick-start guide for learning Bar bending schedule from scratch.
S.No. Particulars Result
1. Standard Length of the Steel Bar
(Bars are sold at standard Length)
12m or 40'
2. Weight of Bar
for length = 1m
D2
/162
(were D = Dia of Bar)

3. S.No. Particulars Result
Ex: If length of bar is 12m with 10mm Dia then ,
Weight of bar = D2
/162
Therefore for length 1m = 1m x D2
/162
= 1 x 102
/162 = 0.61 Kgs
For length 12m = 12 x 102
/162
= 7.40Kgs
7.40Kgs
3. Density of Steel 7850Kg/m3
Below I am discussing the different concepts of Bar Bending schedule which are very useful
while working with BBS. All these concepts are used in BBS design calculation of any structural
member. So be familiar with the below concepts. To keep it clear, firstly the concepts are
discussed and in the end
this post is closed with an example of BBS calculation of a member.
1. Hook Length or Cutting length of Stirrups:-
The hook length is commonly provided for stirrups in beams and ties in columns. In general,
Hooks are added at the two ends of the rebar in stirrups or ties.
Hook Length = 9d (d is dia of the bar)
Below image makes you clear why the Hook length = 9d
From above fig, length of hook = [(Curved Portion) + 4d] =[(4d+d)+4d] = 9d
Hook Length = 9d [d is Diameter of the Bar]
Example Calculation considering stirrup with the hooks at ends:

4. For clear understanding, look at the below image for calculation of the total length of stirrup the with
two hooks at ends
Total Cutting Length of stirrup or tie = Total length of Bar + 2 x Hook Length (Two hooks)
Total Cutting Length = L+2(9d)
Therefore Total Cutting length = L+18d (d is the Diameter of a bar)
Hope, now you are clear with the Hook length calculation.
2. Bend Length:-
The Bend length calculation is different for Cranked bars (bentup bars) and bends at corners.
The bars are usually cranked in Slabs and bars are bent at corners in Stirrups or ties.
(i) Bend Length calculation in Cranked Bars:-
As Shear stress is maximum at supports in Slab. To resist these stresses we usually crank the bars at
the ends of supports in the slab. The below figure depicts the bent up bar in Slab. To calculate the
bend length the below procedure is followed.
From the above figure as the bar is bent at an angle θ0
the additional length (la) is introduced.
Where, la = l1 – l2–(i)
Tanθ = D/l2 ; Sinθ = D/l1

5. Hence l1 = D
/Sinθ and l2 = D
/tanθ
Therefore from (i) :- la = D
/Sinθ – D
/tanθ
Giving different θ values as 300
, 450
, 600
results different additional length la values as below.
θ0 D
/Sinθ
D
/tanθ la =D
/Sinθ – D
/tanθ
300
D/0.500 D/0.573 0.27D
450
D/0.707 D/1.000 0.42D
600
D/0.866 D/1.732 0.58D
900
D/1 0 1D
1350
D/0.707 D/-1 2.42D
The additional length is added to the total length of the bar if the bars are cranked at a certain
angle.
Example Calculation considering Bent up bar in Slab (Cranked bar):-
To keep the crank bar in position, an extra bar of length (L/4) is provided below the crank bar as
shown in the below figure.
Therefore, the total length of bar = L+0.42D+0.42D+(L/4)+(L/4) = 1.5L+0.84D
(ii) Bend Length calculation when bars are bent at corners:-
The important standards used while calculating the bend length at corners
1. 45° Bend length = 1d 2. 90° Bend length = 2d 3. 135° Bend length = 3d
Here, ‘d’ = Diameter of bar

6. Example Calculation considering stirrup with the bends at corners:
From above fig, There are 3 bends which are bent at an angle of 90° and two bends are bent at
an angle of 135°
Total bend length = 3 x 90 Bend length + 2 x 135 Bend length
= 3 x 2d + 2 x 3d = 12d = 12 x 8 = 96mm
Below table represents the total length of bar calculation for different types of bar shapes.
Bar Shapes
Total
Length of
Hooks
Total Bend
Length
Total Length of Bar
Straight Bar Two
Hooks
= 9d + 9d
= 18d
No bend 𝑙+ 18D
Bent Up at one End only Two
Hooks
= 9d + 9d
= 18d
One bend
bent at an
angle 45
= 0.42D
𝑙 + 18D + 0.42D

7. Bar Shapes
Total
Length of
Hooks
Total Bend
Length
Total Length of Bar
Double Bent up Bar Two
Hooks
= 9d + 9d
= 18d
Two
bends
bent at an
angle 450
𝑙 + 18D + 0.42D +
0.42D
=l+18D+0.84D
Overlap of bars Two
Hooks
= 9d + 9d
= 18d
No bends Overlap Length
=(40d to 45d)+18d
3. Overlap Length / Lap Length in Reinforcement:-
The standard length of Rebar is 12m. Suppose the height of the column is 20 m. To purvey this
requirement, two bars of length 12m and 8m are overlapped (joined) with overlap length.
Overlap Length for compression members (columns) = 50d
The Overlap Length for tension members (beams) = 40d

8. Have you seen the below picture on your top floor of the building? We generally project some
length of Bar on the last floor i.e., 50D. It is used for further construction purpose. (Constructing
a new floor)

9. How to Prepare Bar Bending Schedule in Column:
To understand clear, Here I am considering the below structural member RCC Column and
preparing a BBS for it.
BBS of Column
Structural Member Column
(3mx0.3mx0.3m)
Bar Marking 1. Main Bars
2. Stirrups
Dia of Bar 1. Main Bars = 16mm ;
2. Stirrups = 8mm
No. of Bars used 1. Main bars = 4
2. Stirrups = 30
Cutting length 1. Main bars = 3.16m
2. Stirrups = 2.64m
Total Length of bar 1. Main bars = 18.4m
2. Stirrups = 43.2m
Weight of Steel bar 1. Main bars = 29Kgs
2. Stirrups =17Kgs

10. Calculation part of above table:
No. of Bars calculation:
Main bars = 4
To calculate the No. of longitudinal bars adopt spacing between bars is 0.1m
No. of Longitudinal bars = Length of column / Spacing = 3/0.1 = 30bars
Longitudinal bars = 30
Cutting length calculation:
Main bars = 3m + 50d + 50d = 3 + 50×0.016 + 50×0.016 = 4.6m
Stirrups:
Hook length = 9d + 9d = 18d = 18×0.08=1.44m
Bend length =3 x 900
Bend length + 2 x 1350
Bend length
= 3 x 2d + 2 x 3d = 12d = 12 x 8 =0.096m
= l +hook length + bend length = 0.3+0.3+0.3+0.3 +0.144+0.096=1.44m
Hence for Main Bars = 4.6m ; Longitudinal bars = 1.44m
Total Length of Bars:
Total length of Main bars = No. of Main bars x length of one bar
= 4 x 4.6 = 18.4m
Total length of Longitudinal bars=No. of longitudinal bars x length of one bar
=30×1.44=43.2m
Weight of steel bar:
Weight of steel bar for 1m = 1m x D2
/162
Total weight of Main bars = 18.4 x 162
/162 = 29Kgs
Total weight of longitudinal bars = 43.2 x 82
/162 =17Kgs
Total weight of steel bar required to do BBS of above column = 46Kgs
Important rules while preparing Bar Bending Schedule:-
 The bars used in building should be grouped together for each structural unit and listed
separately for each floor.
 Bars are listed in numerical order.
 To identify the bar in the bundle of bars, each bar is uniquely labelled with reference details
(Length of the bar, size of the bar, Shape of the bar)

11.  The type of bar and shape of the bar should be in accordance with B8666.
 It is essential that the bar mark reference on the label attached to a bundle of bars refers
uniquely to a particular group or set of bars of defined length, size, shape and type used on
the job.
 The cutting length and bending length calculations are separately calculated and not
included in the detailed list. Like I have listed the Bar Bending details in a table and
calculations are done separately.
Use of Bar Bending Schedule:
 BBS helps to estimate the total quantity of steel required for the construction of building or
structure. It helps to quote for tender the cost incurred by steel.
 Finding the cutting length and bending length in reinforcement detailing improves the
quality of construction and minimize the wastage of steel, makes an economic construction
 With the help of reinforcement drawings, cutting and bending can be done at the factory and
transported to the site. This increases faster construction and reduces the total construction
cost.
 For site engineers, It becomes easy to verify the cutting length and bending length of the
reinforcement before placing the concrete.
How to calculate Cutting length of Stirrups in Beam and column
To cater the stresses and loads in RCC, Bars are bent to different shapes in the bar bending
schedule. Different shapes of bars have different cutting length. In this post, we are going to
explain you about “How to calculate or find the cutting length of Stirrups for different shapes”.
Remember,
The transverse reinforcement provided in Column is called Ties and the transverse reinforcement
provided in Beam is called Stirrups. But on-site, we usually call both transverse reinforcements
as Stirrups.
The prime reason for providing the stirrups in the beam is for shear requirements and to keep the
longitudinal bars in position. If you wanted to know more about the why stirrups & ties provided
in the beam and column.
Deducting the concrete cover is most important in Bar bending, if you dont know how to deduct
the concrete cover then refer this post

12. Concrete Cover deductions in Beams, Columns, Slab, Footings
Steps involved in finding the cutting length of stirrups:-
1. Look at the size of column or beam from drawings
2. Adopt Dia of the bar (generally 8mm Dia is used for stirrups)
3. Deduct the concrete cover or clear cover
4. Find the total outer length of stirrup after deducting concrete cover.
5. Add the length of the hook to the length of the stirrup
6. Deduct the length of bends
7. Use below formula to find the total cutting length of stirrups
Formula:
Cutting Length of Stirrups = Perimeter of Shape + Total hook length – Total
Bend Length
Important Basic formulas:
Perimeter of Rectangle = 2 ( length + breadth)
Perimeter of Square = 4 x side length
Perimeter of circle or Circumference of Circle = 2πr = πd (r= radius, d= Diameter of Circle)
Typical Diagram of Stirrup:-
Refer the below image of the typical diagram of stirrup for clear understanding about x & y length,
bends, hooks and concrete cover.

13. In the above image, there are 5 bends at 4 corners, 2 hooks and concrete cover around the stirrup.
x = length of the stirrup in the x-direction after deducting concrete cover &
y = length of the stirrup in the y-direction after deducting concrete cover.
Important standards used in Bends & Hooks:
The below standards are most important in calculating the hook length and bend lengths at corners
while finding cutting length of stirrups.
 1 Hook length = 9d or 75mm
 45° Bend length = 1d
 90° Bend length = 2d
 135° Bend length = 3d
Remember, d = Diameter of Bar
Cutting length for Rectangular Stirrups:-
Rectangular column or rectangular beam is the most commonly used shape of the column in any
construction. In this shape of beam or column, a rectangular stirrup is usually adopted.
1. Considering the below Rectangular column size 230mm x 450mm for calculation purpose
1. Adopting Dia of Bar used for stirrups is 8mm
2. Deducting the concrete cover 20mm from all sides
x = 230 – 20-20 = 190mm
y = 450-20-20 = 410mm

14. 1. Total Length of the hooks:
From fig, There are two hooks which means 9d+9d = 18d
2. Total Length of Bends:
From above fig, There are 3 bends which are bent at an angle of 900
and two bends are
bent at an angle of 1350
Total bend length = 3 x 900
Bend length + 2 x 1350
Bend length = 3 x 2d + 2 x 3d = 12d =
12 x 8 = 96mm
Total Cutting length of Rectangular Stirrup = Perimeter of Rectangle + Total Hook length –
Total Bend Length
= 2 (x+y) +18d – 12d = 2(190 + 410) + 18 x 8 – 12 x 8 = 1248mm = 1.248m
Cutting length for Square Stirrups:-
Considered the column size as 450mm x 450mm

15. 1. Adopting Dia of Bar used for stirrups is 8mm
2. Deducting the concrete cover 25mm from all sides (in square all sides are equal)
x = 450- 20-20 = 410mm
y = 450-20-20 = 410mm, Hence x = y (in square all sides are equal)
1. Total Length of the hook:
There are two hooks which mean 9d+9d = 18d
2. Total length of Bends:
There are 3 bends which are bent at an angle of 900
and one is bent at an angle of 1350
.
Total bend length = 3 x 900
Bend length + 2 x 1350
Bend length = 3 x 2d + 2 x 3d = 12d =
12 x 8 = 96mm
Total Cutting length of Square Stirrup = Perimeter of Square + Total Hook length – Total
Bend Length = 4 x 410 +18d – 12d = 1648mm = 1.64m

16. Cutting Length for Circular Stirrup:
1. Considered the column dia as D = 1000mm
2. Adopting Dia of Bar used for stirrups is d =8mm
Deducting the concrete cover from diameter of column
D = 1000-25-25 = 950mm
1. Circumference length of Ring = πD = 950 x 3.14 = 2983mm
2. Total Length of the hook:
There are two hooks which means 9d+9d= 18d
3. Total Length of Bends:
There are 2 bends which are bent at an angle of 1350
Total bend length = 2 x 1350
Bend length = 2 x 3d = 6d= 6 x 8 = 48mm
Total Cutting length of Circular Stirrup or Ring = Circumference of Circle + Total Hook length – Total
Bend Length = 2983 +18d – 6d =3079mm =3.07m

17. Cutting Length for Diamond Stirrups:
Considered the Column size 400mm x 400mm
1. Adopting Dia of Bar used for stirrups is d = 8mm
2. Deducting the concrete cover 25mm from all sides
x = 400-20-20 = 360mm y = 400-20-20 =360mm
1. From Pythagorean theorem,
Hypotenuse2=(Opposite)2 + (Adjacent)2
H2
=(x/2)2
+( y/2)2
H2
=1802
+ 1802
=> = √(254)2
= 254mm
2. The total length of stirrup = 4 x H =4 x 254 = 1016mm
3. Total Length of the hook:
There are two hooks which means 9d+9d= 18d
4. Total length of Bends:
There are 3 bends which are bent at an angle of 900
+ 2 bends which are bent at an angle
of 1350
Total bend length = 3 x 900
Bend length + 2 x 1350
Bend length= 3 x 2d + 2 x 3d = 12d =
12 x 8 = 96mm

18. Total Cutting length of Diamond Stirrup = Perimeter of Diamond shape + Total Hook length
– Total Bend Length = 1016+144-96 = 1064mm = 1.064mm
Bar Bending Schedule for footings |Estimation of Reinforcement in
footings
Bar Bending Schedule for footings :-
Bar Bending schedule plays a vital role in the construction of High rise buildings. It is very
important to learn Bar Bending Schedule for finding out the quantities of Steel reinforcement
required for every component of the building.
For Suppose, consider the case of high rise buildings, It requires tons of steel to complete 10+ floor
building. It’s impossible to order all the steel required for whole construction at a time it creates a
problem of space and also steel is prone to corrosion by the contact of water (rain). To avoid this,
high rise building orders reinforcement (steel) as per requirement. Firstly they find the Estimation
of Steel reinforcement in footings (steel quantities) [Bar Bending Schedule for footings], required
for the construction of footings. After the completion of footings they go for next order and so on.
Quantity of Reinforcement (Steel) required for footings / Bar
Bending Schedule for footings:-
The procedure to finding out the quantities of steel required for the footings, We are considering
the below footing plan.

19. Observations from the above fig:
 F1, F4, F7 is Plain footing (1.0×1.0×0.8)
 F2 is Stepped Footing (0.9×0.9×1.35)
 F3, F8 is Isolated footing (0.9×0.9×0.5)
 F5 is Combined Isolated footing (4.2×1.7×0.9)
 F6 is Shoe footing (0.6×0.6×0.4)
True dimensions and shapes of the footings are decided and designed by the structural engineer based on
soil history, type of construction, the total expected load of the structure. All the dimensions of the above
columns considered only for explanation purpose.

20. Steps involved in calculating the bar bending schedule of a footings:-
Remember, Steel required for construction is ordered in Kgs or Number of Bars. The standard size
of each bar is 12m. The final output of BBS calculation is in Kgs or in Number of “12m” Bars.
To make it easier calculation is divided into two parts, X bar Calculations and Y bar calculations.

21. X Bars are Horizontal bars in X direction and Y Bars are vertical one projected in Y Direction.
1. Deduct the concrete cover to find the dimensions of bars.
2. Find the Length of single X Bars & Y Bars
3. Find the total length of X bars. & Y bars
4. Calculate the weight of steel required per 1m
5. Calculate the total number of 12m bars required
6. Find the total weight of steel required.
Plain footing Bar Bending schedule:
For the calculation of the total quantity of steel required for the Plain footing, we are adopting these
dimensions for bars.
Adopted:-
 Dimensions of Footing are 1.0 × 1.0 × 0.9 (Length × Breadth × Depth)
 Plain mesh is adopted for F1, F4, F7 footings
 Dia of X Bars is 16mm (Dia 16mm @ 100mm C/C)
 Dia of Y Bars is 12mm (Dia 12mm @ 100mm C/C)
 which means Center to center spacing between X bars & Y bars is 100mm

22. Remember, Proper Concrete cover should be adopted for the reinforcement in Footings to resist it from
corrosion.
Concrete Cover deduction:
As per condition, concrete cover of 0.1m is deducted from all sides of mesh. True dimensions
post deducting is 0.8×0.8 (length and breadth)
Refer below image for more details:
Length of Each X bar = 0.8m
Length of Each Y bar = 0.8m
No. of X bars
[(Y Bar Length)/Spacing]+1
= [0.8/0.1]+1 = 9bars
No. of Y bars
[(X Bar Length)/Spacing]+1
= [0.8/0.1]+1 = 9bars
Total Length
of X bars
= Length of each X bar ×
No. of X Bars = 0.8 × 9 =7.2m
Total Length
of Y bars
= Length of each Y bar ×
No. of Y Bars = 0.8 × 9 =7.2m
Total No. of ’12m’
X bars
= 7.2/12 = 0.6bars
Total No. of ’12m’
Y bars
= 7.2/12
= 0.6bars

23. Weight of steel required for 1m of 16mm bar
= D2
/162
= 162
/162
= 1.58kg/m
Total weight of steel required for X bars
= 1.58 × 7.2
= 11.37Kgs
Weight of steel required for 1m of 12mm bar
= D2
/162
= 122
/162
= 0.88kg/m
Total weight of steel
required for Y bars
= 0.88 × 7.2
= 6.33Kgs
Total Weight of Plain Mesh
= Weight of steel required for X bars + Weight of steel required for Y bars
= 11.37Kgs+6.33Kgs =17.70Kgs
Isolated footings Bar Bending Schedule :-
For the calculation of the total quantity of steel required for the Isolated footing, we are adopting below
dimensions for bars.

24. Adopted:-
 Hook mesh is adopted for F3,F8 footings
 Dimensions of Footing are 0.9×0.9×0.5 (Length × Breadth × Depth)
 Dia of X Bars is 16mm (Dia 16mm @ 100mm C/C)
 Dia of Y Bars is 12mm (Dia 12mm @ 90mm C/C)
 which means Center to center spacing between X bars is 100mm & Y bars is 90mm
Remember Proper Concrete cover should be adopted for the reinforcement in Footings to resist it from
corrosion.
Concrete Cover deduction:
As per condition, concrete cover of 0.1m is deducted from all sides of mesh. In hook mesh, hook
is provided at the end of each bar. Each bar has two ends and therefore, hook length is included in
the calculation of length of bar
Hook Length = 9d (d is the dia of bar)
Total Hooks for each bar = 2
True dimensions post deducting concrete cover is length = (0.7m+2x9d) & breadth = (0.7m+2x9d)
Refer below image for more details

25. Length of Each X bar
= 0.7+2×9d
d = 16mm = 0.016m
= 0.7+2×9×0.016 = 0.988m
Length of Each Y bar
= 0.7+2×9d
d = 12mm = 0.012m
= 0.7+2×9×0.012
= 0.916m
No. of X bars
[(Y Bar Length)/Spacing]+1
= [0.7/0.1]+1
= 8bars
(Don’t include hook
length in calculating no. of bars)
No. of Y bars
[(X Bar Length)/Spacing]+1
= [0.7/0.09]+1
= 9bars
Total Length of X bars
= Length of each X bar × No. of X Bars
= 0.988 × 8 =7.9m
Total Length of Y bars
= Length of each Y bar × No. of Y Bars
= 0.916 × 9 =8.24m
Total No. of ’12m’ X bars
= 7.9/12
= 0.65 bars
Total No. of ’12m’ Y bars
= 8.24/12
= 0.68 bars
Weight of steel required for
1m of 16mm bar
= D2
/162
= 162
/162
= 1.58kg/m
Total weight of
Steel required for X bars
= 1.58 × 7.9
= 12.48Kgs
Weight of steel required for
1m of 12mm bar
= D2
/162
= 122
/162
= 0.88kg/m
Total weight of
Steel required for Y bars
= 0.88 × 8.24
= 7.25Kgs

26. Stepped footings Bar Bending Schedule:
For the calculation of the total quantity of steel required for the Plain footing, we are adopting these
dimensions for bars.
Adopted:-
 Hook mesh is adopted for F2 footings
 Dimensions of Footing are 0.9×0.9×1.35 (Length × Breadth × Depth)
 Dia of X Bars is 16mm (Dia 16mm@110mm C/C)
 Dia of Y Bars is 20mm (Dia 12mm@115mm C/C)
 which means Center to center spacing between X bars is 110mm & Y bars is 115mm
Remember Proper Concrete cover should be adopted for the reinforcement in Footings to resist it from
corrosion.
Concrete Cover deduction:
As per condition, concrete cover of 0.1m is deducted from all sides of mesh. In hook mesh, hook
is provided at the end of each bar. Each bar has two ends and therefore, hook length is included in
the calculation of length of bar
Hook Length = 9d (d is the dia of bar)
Total Hooks for each bar = 2
True dimensions post deducting concrete cover is length = (0.7m+2×9d) & breadth = (0.7m+2×9d)
Refer below image for more details

27. Length of Each X bar
= 0.7+2×9d
d = 16mm = 0.016m
= 0.7+2×9×0.016 = 0.988m
Length of Each Y bar
= 0.7+2×9d
d = 12mm = 0.012m
= 0.7+2×9×0.020 = 1.06m
No. of X bars
[(Y Bar Length)/Spacing]+1
= [0.7/0.11]+1 =~7bars
(Don’t include hook
length in calculating no. of bars)
No. of Y bars
[(X Bar Length)/Spacing]+1
= [0.7/0.115]+1 = ~6bars
Total Length of X bars
= Length of each X bar × No. of X Bars
= 0.988 × 7 =7.9m
Total Length of Y bars
= Length of each Y bar × No. of Y Bars
= 1.06 × 6 =6.36m
Total No. of ’12m’X bars = 7.9/12 = 0.65bars
Total No. of ’12m’
Y bars
= 6.36/12
= 0.53 bars
Weight of steel
required for
1m of 16mm bar
= D2
/162
= 162
/162
= 1.58 kg/m
Total weight of
Steel required for X bars
= 1.58 × 7.9
= 12.48 Kgs
Weight of steel
required for
1m of 12mm bar
= D2
/162
= 202
/162
= 2.46 kg/m
Total weight of steel
required for Y bars
= 2.46 × 6.36
= 15.64Kgs

28. Total Weight of Hook Mesh
= Weight of steel required for X bars + Weight of steel required for Y bars
= 12.48Kgs+15.64Kgs =28.12Kgs
Bar Bending Schedule for Slab:-
There are 16 different types of slabs in construction. Well, the thickness of slab generally varies
between 4″ to 8″. We generally adopt 6″ (0.15m) slab thickness. For occasionally heavy loads we
adopt 8″ and above thickness slabs.
Quantity of Reinforcement (Steel) required for Slab Or Bar Bending Schedule for Slab:-
In this post, I am finding out the Estimation of Steel reinforcement required for a Slab to work on
this I considered a plan as shown below.
Primarily slabs are classified into two types One-way Slab and Two-way slab to know more
about the differences refer here.
In one-way slab, Main bars are provided in shorter direction (Cranked bars) and distribution bars
are provided in Longer direction (Straight bars). Whereas in Two-way slab Main bars (cranked
bars) are provided in both directions. Usually, the Two-way slab is adopted when the length and
width of the slab is more than 4m.
Well to make you perfect in Bar Bending Schedule for a slab, I am considering a One-way slab
and two way slab as shown in the figure. Main bars and distribution bars are provided in the One-
way slab. In two way slab, distribution bars are provided in both sides of slab.
Distribution bars:- These bars are straight bars.
Main bars:- These bars are cranked bars. Main bars are cranked at an angle of 45 Degree with
the length of 0.42D
Where, D = Depth of Slab- Top cover – Bottom cover
Extra Bars:- The extra bar is provided at the bottom of Cranked bars to maintain the framework of
the slab.
The length of Extra bar is L/4.
Steps to calculate the Reinforcement required for Slab:-
1. Deduct the cover for finding length of bar.
2. Evaluate the length of the distribution bar
3. Calculate the Value of ‘D’ (Depth of slab- Top cover- Bottom cover)

29. 4. Find out the No. of Bars
5. Compute the Total wt of steel required for slab reinforcement.
Consider,
Dia of bars = 10mm , Spacing between bars = 0.10m , Depth of Slab = 0.15m
Floor Slab – 1 (Two-Way Slab):-
Bars along X Axis:-

31. Bars along Y Axis:-

32. Bar Bending Schedule of Staircase {Step by Step procedure
of Doglegged Staircase}
Bar Bending Schedule of Doglegged Staircase:-
To calculate the Bar Bending Schedule of Doglegged staircase, I request you to learn the Basics
of Bar bending schedule and also the components of Staircase
Staircase:-
Stairs provide access to the various floors of the building. The stair consists of series of steps with
landings at appropriate intervals. The stretch between the two landings is called flight. The Space,
where stairs are provided is called staircase.
To make it ease in understanding, I am calculating the quantities of a staircase by dividing into
components.
Components of Staircase:-
Waist slab: Waist slab refers to a slab of the stair that is inclining from the floor slab to the landing
slab.
Flight: The series of steps between floor and landing.
Landing : The level of floor between flight.
Step: The step consists of Riser and tread.
Tread: The tread is the flat part that you step on.
Riser: The riser is the vertical(up and down) part between each tread in the stairway.
Considering the below plan for finding out the steel quantities of bar bending
schedule:-
All values in the below plan are adopted.

34. Finding out the Actual Length of Waist Slab:-
Steps to calculate the reinforcement required for Doglegged
Staircase:-
1. Find the length of X Bar & Y bar
2. Find the No. of X Bars & Y bars
3. Evaluate the total length of X Bars & Y Bars
4. Find out the total weight of steel required.
From the above figure, staircase consists of two waist slabs 1 & 2. As
reinforcement quantities varies among waist slab 1 & 2.Let us calculate the
quantities individually. Remember, the above mentioned steps are same for
both slabs.
Before diving into the calculation part, ensure that you are perfect in
deducting the concrete cover. If not? follow the below post first
Waist Slab-1:- (Adopt Dia 8mm @100mm)

38. Finding out the Actual Length of Waist Slab:-
Steps to calculate the reinforcement required for Doglegged
Staircase:-
1. Find the length of X Bar & Y bar
2. Find the No. of X Bars & Y bars
3. Evaluate the total length of X Bars & Y Bars
4. Find out the total weight of steel required.
From the above figure, staircase consists of two waist slabs 1 & 2. As
reinforcement quantities varies among waist slab 1 & 2.Let us calculate the
quantities individually. Remember, the above mentioned steps are same for
both slabs.
Before diving into the calculation part, ensure that you are perfect in
deducting the concrete cover. If not? follow the below post first
How to Deduct concrete cover
Waist Slab-1:- (Adopt Dia 8mm @100mm)

41. Waist Slab-2:- (Adopt Dia 8mm @100mm)

43. Landing-1:- (Adopt Dia 8mm @100mm)
X bars of Landing-1 are tied with Slab reinforcement. hence, there is no
further need of calculating the steel required for Landing-2.
The X bars of Landing-1. are already added and calculated in Waist slab.
Now, calculate the Y bars of landing-1.
Concrete cover has been deducted from the length of Y bar from both
sides.

45. Waist Slab-2:- (Adopt Dia 8mm @100mm)

47. Floor Space Index (FSI) and Floor Area Ratio
What is FSI?
The full form of FSI is the “Floor Space Index” and it is the ratio of the total area of the plot to
the built-up area on the plot. FSI is a rule followed in the development control norms of many
cities. It directly tells us about permissible floor areas that can be built upon on a given plot. FSI
is also called Space ratio, plot ratio and area ratio.
FSI Formula
Floor Space Index = (Total Area of all the Floors of Building / Total Plot Area of Building)
Different cities have different FSIs. The FSI value is regulated or decided by the DTCP
(Directorate of Town and Country Planning ) Dept. The DTCP gives different permissible FSI
values based on the following factors.
Importance of FSI in Building Construction
FSI value influences the value of land in an area. The FSI value is local and varies from region to
region. More the FSI values, the more the utilization of space. Ultimately, less the property’s price.
Because, the contractor can build more and the builder will sell more, and thus they will charge a
reasonable fee from the home buyer.
FSI allows you to construct the building as per the rules and regulations. If the building plan is
prepared with the knowledge of FSI, approval and NOC will not be questioned if you know the
floor space index for the first time.

48. Permissible FSI value depends on the following factors:
 Size of the plot and location of the plot (is it urban or rural etc)
 Purpose of the building ( commercial building or residential apartment or industry etc.).
 The width of the side road.
 Availability of electricity, water and sewer lines.
 Type of building:
 Ordinary building (max of two floors)
 Special building ( min of 2 floors and max of 4 floors)
 Multi storeyed building (more than 4 floors)
What is Buildup Area and Plot Area?
What is FAR?
Both FSI and FAR are the same. FAR means Floor Area Ratio. FSI is expressed as an index and
FAR as a ratio. FSI of 1.8 is termed as FAR of 180% (FAR 180)
FAR = FSI x 100
How to Calculate Built-up area of A Building using FSI:-
Let’s say you have 3000 square feet of plot and you want to build a Multi storeyed building on
that land for commercial purposes.
Based on the type and purpose of construction, obtain the FSI value of your plot from your state
or province official govt website.
Let us consider the FSI value obtained from government for your location of the plot and type of
construction is 2.
Calculation :
FSI formula = Total built up area / Total plot area Total Builtup area = FSI x Total plot area
FSI = 2, Total Plot area = 3000sft
Total Built Up area = 2×3000 = 6000sft.
The multi-storied building has a minimum of 5 floors
Considering 5 floors construction 6000/5 =1200Sft
if you are considering the 6 floors construction, each floor area should not exceed more than
1000Sft.
What Is Premium FSI?
Premium FSI is also called as Paid Floor Space index. If your plot stands in a place of limited FSI
( less FSI) and you want to extend the allowable permissible area of construction then you can opt
for Premium FSI paying additional charges to local authorities. But, to be eligible for this option,
the width of the road adjacent to your land must be more than 30 feets.
30 – 40 Feet Road Width 20% Premium FSI
40 – 60 Feet Road Width 30% Premium FSI

49. Greater 60 Feet Road Width30% Premium FSI
which means, if your land adjacent to the road has a width of 30-40 feet, you can apply the
option of 20% premium FSI which means you can build 20% more than the allowable FSI.
Example:
Suppose you are planning to construct a building in the land of 2000 fts which is located near
60ft road where your normal FSI obtained from local authorities is 1.5. then you can extend the
premium FSI by 40%
Built Up area = (FSI+40% extra of FSI) x Total Plot area
= (1.5 + 1.5×40/100) x 2000
= (2.1) x 2000
= 4200sft
Advantages and Disadvantages of Floor Space Index:
Advantages:
 F.S.I can be considered as a ban on construction, but it has many advantages for the city.
 It helps in maintaining the proportion of open space and built-up space in an area.
 This ensures a clear horizon for the area.
 Good FSI values ensure the good development of the project.
 It helps to maintain a balance between continuous, planned growth and development.
Disadvantages:
 The Lower Floor Space Index imposes restrictions on the development of the city.
 If the floor space index is too high, it results in non-eco-friendly and haphazard development of
the city.
 For lesser FSIs, Utilization decreases and the price of property increases.
What is Plot area, Carpet Area, Setback area, Plinth Area,
Buildup Area in civil engineering
Well, If you are a civil engineer, You must know how to read a floor plan of the building. A good plan
gives a better idea of whole structure in single sheet. To make it ease, In the plan we use many terms for
denoting and identifying the particular areas of a building. Here I am discussing different types of areas
which we generally use them in identifying the type of area in the Plan. (Plot, Built-up, plinth, Setback,
carpet, super built-up area)
1. Plot Area:

50. The area which is surrounded by a boundary line (fencing) is called as Plot Area. In simple words,
the total area which belongs to you in a city or town is termed as a Plot area. The term Plot area is
majorly used in gated communities, townships and named as Plot Area 1, PA-2 etc. They are useful
in identifying the plot of a particular individual.
2. Built Up area/Plinth Area:-
The total building area in plot area is referred as Built up area. In simple, Area excluding empty
space around the building is called Built up area or Plinth area.
Built up Area = Carpet area+ Thickness of All walls + balcony
3. Setback area:
The empty space around the building is called Setback area. The setback area is decided by
Municipal Authority. In India, we leave 4 ft from all the sides of the building. The reason behind
leaving setback area is to make ease for moving vehicles, ventilation and during emergency
purposes. However set back area increases for High rise building and may go up to several meters.
Setback area = Plot area – Built-up Area
4. Carpet area:
Carpet Area is an area which is enclosed within walls. In simple words, Area excluding walls in
the built-up area is called as carpet area. It is a working area of a building. Generally, carpet area
is around 85-90% of built area.
Carpet Area = Built-up Area- Area of walls
5. Super Built-up Area:-
Super Built Up Area is the built up area plus proportionate area of common areas such as the
Swimming pools, Staircase, lobby, lifts, open verandahs etc.
The term Super built up area is generally used in Real Estate (while buying property) builders may
add 20% of total cost of apartment to the super built-up area.

51. Refer the following Plan of a building in a plot picture for clear understanding.
Super Built-Up Area = Setback area+Built-up Area+20% of common area
Hope now you are aware of Plot, Built-up, plinth, Setback, carpet, super built up area which we
use in civil plans and other real estate purposes.