# Bar Bending Schedule of Two way Slab – 1 Best Rule to Calculate

## Bar Bending Schedule of Two way Slab

Hello Friends

Today We will discuss about the Bar Bending Schedule of Two way Slab

Before moving forward first you should know that What is bar Bending Schedule and what is the importance of bar bending schedule in building construction or civil engineering

What Is Bar Bending Schedule

Bar Bending Schedule is the process of cutting & bending of Reinforcement bars into required shape, which gives the complete information about reinforcement steel bars like Location and marking of bars, types of bars, size of bar, cutting length of bar,bending details of bar, number of bar, Shapes of Bars and total quantity of steel,

Importance of Bar Bending Schedule

As you know that all the site workers are non technical and they has lack of knowledge about steel . So, It is the responsibility of a site supervisor to give them details of cutting , bending of steel. So , A bar bending schedule is the data which help the supervisor for this process.

1). B.B.S avoids wastage of steel reinforcement and thus save project cost.

2). it provides better estimation of reinforcement steel required for each and every structure members.

3). It enables easy or fast preparation of bill of construction work for clients and contractors.

So, Lets Move on the topic,

## Bar Bending Schedule of Two way Slab

Given,

Diameter of all bars = 16 mm.

Spacing                      = 100 mm.

Top and Bottom Clear Cover = 25 mm.

Slab Thickness         = 150 mm.

Development length (Consider) = 40 d

Calculation

No. Of Main bars formula  =  Length Of Slab / Spacing +1

Step 1

Calculation of numbers of bars

1). For Length (L 1) side:-

No. Of Main bars  =     L 1 / Spacing + 1

No. Of Main bars  =    4000 / 100 + 1

= 41 Nos.

No. Of Crank bars  = 21 Nos.

No. Of Straight Bar = 20 Nos.

2). For Length (L 2) side

No. Of Main bars   =     L 2 / Spacing + 1

No. Of bars            =    5000 / 100 + 1

= 51 Nos.

No. Of Crank bars  = 26 Nos.

No. Of Straight Bar = 25 Nos.

Step 2

Cutting length of Bars :-

(i). Cutting Length Of L 1 side (Crank) Bar

Length of Slab (L 1) + ( 2 x development Length) + ( 2 x inclined Length) – ( 45* Bend x 4 )

– ( 90* Bend x 2)

= 5000+(2 x L d) + ( 2 x inclined length ) – ( 1 d x 4 ) – ( 2 d x 2 ).

Always remember the,

Inclined Length = 0.42 D

For 45*        = 1 d

For 90*        = 2 d

Cutting Length Of Main Bar (Crank) = 5000+(2 x 40 d) + (2 x 0.42 d) – (1 d x 4) – (2 d x 2 ).

= 5000 + ( 2 x 40 x 16 ) + ( 2 x 0.42 d ) – ( 1 x 16 x 4 )  –  ( 2 x 16 x 2 ).

= 5000 + 1280 + ( 2 x 0.42 d) – 64 – 64

Now, what is D

D = Slab Thickness – 2 Sides Clear Cover – Diameter of  Bars.

= 150 – 50 – 16

= 84 mm.

D = 84 mm.

Cutting Length = 5000 + 1280 + ( 2 x 0.42 x 84) – 128

=  5000 + 1280 + 70.56 – 128

= 6350.56 – 128 mm.

= 6222.56 mm or 6.23 meter.

Cutting Length Of ( Crank ) Bar = 6.23 meter.

For 21 no. of bars = 21 x 6.23     = 130.83 meter.

Weight of steel        =  D x D/162 x L

= 16 x 16 / 162 x 130.83

=   1.58 x 130.83

=     206.71 Kg.

1(ii). Cutting Length Of (straight) Bar side (L 1)

Length of slab (L 1) + ( 2 x development length )

(ii). Cutting Length Of (straight) Bar

Length of slab (L 1) + ( 2 x development length )

= 5000 + ( 2 x 40 d )

= 5000 + ( 2 x 40 x 16 )

= 5000 + 1280

= 6280 mm or 6.28 meter.

For 20 No. Of Bars = 20 x 6.28    = 125.6 meter

Weight of steel      = 1.58 x 125.6 = 198.448 Kg

2(i). Cutting Length Of crank bar (L 2) side

Cutting Length Of (L 2) side Bar

Length of slab (L 2) + ( 2 x development length ) x ( 2 x inclined length) – ( 45* bend x 4 ) –

( 90* Bend x 2 )

= 4000 + ( 2 x 40 d ) + ( 2 x 0.42 D ) – ( 1 d x 4 ) – ( 2 d x 2 ).

= 4000 + ( 2 x 40 x 16 ) + ( 2 x 0.42 d ) – (1 x 16 x 4 ) – ( 2 x 16 x 2 )

= 4000 + 1280 + 70.56 – 64 – 64

= 5350.56 – 128  = 5222.56 mm or 5.22 meter.

For 26 No. Of Bars = 26 x 5.22    = 135.72 meter.

Weight of steel      = 1.58 x 135.72 = 214.43 Kg

2(ii). Cutting Length Of (straight) Bar (L 2) side

Length of slab (L 2) + ( 2 x development length )

= 4000 + ( 2 x 40 d )

= 4000 + (2 x 40 x 16)

= 4000 + 1280

= 5280 mm or 5.28 meter

For 25 No. Of Bars = 25 x 5.28    = 132 meter

= 1.58 x  132    = 208.56 Kg

Step 3

3).  Extra Top Bar

No. of extra top bars =    ( L / 4 ) / spacing + 1

3).  Extra Top Bar

Formula     =   ( L 1 / 4 ) / Spacing + 1 x (2)

(i) For length ( L 1 ) side =   ( L 1 / 4 ) / Spacing+ 1 x (2)

=    (5000/4)/100 + 1 x (2)

1250 / 100 + 1 x (2)  = 27 Nos.

Length Of Extra Top Bar = Length of Same As Cutting Length of Straight Bar.

=  6.28 meter.

For 27 No. Of Bars = 27 x 6.28       = 169.56 meter.

Weight Of Steel      = 1.58 x 169.56 =  267.90 Kg.

3).  Extra Top Bar

Formula =   ( L 2 / 4 ) / Spacing + 1 x (2)

(ii) For length ( L2 ) side   =   ( L / 4 ) / Spacing + 1 x (2)

=    (4000/4) / 100 + 1 x (2)

= 1000 / 100 + 1 x (2) = 22 Nos.

Length Of Extra Top Bar = Length of Same As Cutting Length of Straight Bar.

=  5.28 meter

For 22 No. Of Bars = 22 x 5.28      = 116.16 meter

Weight Of Steel      = 1.58 x 116.16 = 183.53 Kg.

Total Weight Of Steel = Weight of L 1 side crank bar + Weight of crank bar L 2 side + weight of straight bar L 1 side + weight of straight bar L 2 side + weight of extra bar L 1 side + weight of extra bar L 2 side

Total Weight Of Steel  =  206.71 + 214.43 + 198.448 + 208.56 + 267.90 + 183.53

Total Weight of Steel =  1279.578 kg.

So, This the the best and easy method to calculate Bar Bending Schedule of Two way Slab. I hope now you will be understand the concept.

Good Bye & Take care

Happy Learning 😆

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