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, Whats the use of BBS? Why we use BBS?

BBS is termed as Calculation of 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.

Well, from 1950 to 2017 lots of modifications and enhancements happening in our world. At that time three storeyed buildings are high rise buildings now we are constructing a building with 200 floors+. There is a massive growth in construction. More population, more need of facilities, more need of space, more construction.

How BBS Changed from 1950-2000:-

Father of Estimation B.N. Datta has given certain recommendations for the usage of steel (bar bending schedule) in different components of buildings. But, he didn’t mention any values if we use more bars in a single element.

Bar Bending MemberPercentage
Slab1% of total volume of concrete
Beam2% of of total volume of concrete
Column5% of total volume of concrete
Footings0.8% of total volume of concrete

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 So, the percentage of steel is increased in a column which reveals that the above-cited values are outdated. ( I am saying outdated “not wrong”) He wrote that book in 1950. Now we are in 2017. He gave recommendations according to the potentiality of construction at that time. Now we are constructing 200 + floors in the small area.

Hope now you are clear that BN Datta didn’t give any recommendations of Bar Bending schedule for high rise buildings.

Well, one article isn’t enough to calculate the amount of steel required for the whole building. In future, I will come up with different posts for calculation of various components of the building. Here I am showing how to calculate the steel required for various components.

Bar Bending Schedule [BBS] :-

bar bending schedule

1. Hook Length or Cutting length of Stirrups:-

The hook length is commonly provided for stirrups. The below mentioned image depicts the cutting length of stirrups.

Hook Length = 9D [D is Diameter of the Bar]

Hook Length Bar Bending schedule

Total Cutting Length of stirrup = Total length of Bar + 2 x Hook Length (Two hooks)

Total Cutting Length = L+2(9D)

Therefore Total Cutting  length = L+18D (D is Diameter of bar)

2. Bend Length:-

Bend Length is usually provided in columns at ends to tie the columns to the footings.

Bend Length = 16D  [D is Diameter of the Bar]

Bend Length Bar Bending Schedule

3. Overlap Length / Lap Length in Reinforcement (Bar Bending Schedule) :-

Suppose the length of building is 20 m. The standard length of Rebar is 12m. We have to join two Re-bars for the total length of building. In order to Join the two bars (overlap). Overlap length is adopted.

Overlap Length for compression members = 40D

Overlap Length for tension members = 50D

[D is the Diameter of the bar]

Overlap Length Bar Bending Schedule

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

Overlap Length Bar Bending Schedule4. Crank Length :-

Crank length is provided in Slab  Shear stress is maximum at supports in Slab. So, to resist this stress we usually crank the bars at the ends of supports in slab.

Crank bar is bent up at an angle of 45degree with the length of 0.42D

D = Depth of Slab-Top Cover-Bottom cover

Crank Length Bar Bending Schedule

5. Extra Bar:-

Now a days Extra bar is also provided under every crank bar. To keep crank bar in position. (Refer above image for clear idea)

The length of Extra bar is L/4.

Bar Bending Schedule Calculator:

Learn how to Estimate the Quantities of Steel (Bar Bending Schedule) for different members of a structure:

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64 thoughts on “Bar Bending Schedule [BBS] Estimate of Steel in Building Construction

  1. nice , further if you now about IRC – Highways and structures please upload also .

    Regards,
    Santoshkumar shrilele/Mumbai/9967447270

  2. Hello sir good morning,
    Sir please also tell me how much of steel is required for 1 floor.
    Tell me one example sir.
    Thank you sir.

  3. Thanks sir share valuable information site …Next part upload surveying important information and process of auto level.

  4. brthr also using 60d grade steel in motorways tel me the please .. nd thnx for sharing this information .. do you have another page on facebook for this information

  5. Thank you for providing many useful data . I appreciate your effort in collecting the valued information and getting it to us so quickly and in a simple manner.

  6. Hello sir m an undergoing civil engineer trainee. My project is quality check and assurance in capex as there is a ongoing construction project. Pls suggest me what I have to do in my project?
    thank you

    • hi Nikhil,
      i suggest you to learn about various quality checks of building materials and how the quality controlled.
      I say its a good opportunity to know how the materials being tested in realtime.

      Cheers!

  7. Thank you for the information. You guys have contributed alot as far as learning more is concerned.May you keep the website rocking high.

  8. Sir . I am much impress by your view on bar bending schedule. Sir can u send plan of building and bar bending schedule ,elevation. Sir I want for case study. Could help me…

  9. Sir, Plese Upload Detailed Bar Bending Schedule in excel sheet of All Concepts like Footings,Beams,Columns,Slabs

  10. I HAVE CONFUSION REGARDING CUTTING LENGTH OF THE STIRRUPS. PLEASE ELABORATE WHETHER THE BEND LENGTH IS DEDUCTED OR NOT TO GET ACTUAL CUTTING LENGTH….LIKEWISE FOR 90 DEGREE BEND 2D, 135 DEGREE 3D AND SO ON….

  11. sir I m going to start my own construction work from footing so . Can you tell me what should I know n what ever work realeted to construction work

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