Bar Bending Schedule Basic Formulas | BBS Formula | What is BBS | Hook Length | Cut Length of Straight Bar | Cut Length of Bend up Bar or Crank Bar | Length of Extra Bars | Hook’s Length Formula for Stirrups | Lap Length:

In this Article today we will talk about the Bar Bending Schedule Basic Formulas | BBS Formula | Hook Length | Cut Length of Straight Bar | Cut Length of Bend up Bar or Crank Bar | Length of Extra Bars | Hook’s Length Formula for Stirrups | Lap Length. These are the important Tips to make and find the steel cutting length.

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Bar Bending Schedule Basic Formulas, Slab BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook’s Length Formula for Stirrups, Lap Length.

What is  Bar Bending Schedule?

In Civil Engineering Bar Bending Schedule is the important part of Estimation chart. In the Bar Bending schedule provides the reinforcement (steel) calculation for reinforcement of concrete column , beam and slab cutting length and also use to find the types of bends of length which we provide in steel structures.

BBS is used in finding cutting length of steel and total weight of steel per unit area. and we can make the bar bending schedule in Ms office Excel software.


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Bar Bending Schedule Basics Formula | Calculation of Reinforcement Shape, Cutting and Bending Lengths:

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Bar Bending Schedule Formulas

1. Hook Length:-

The hook length is commonly provided for stirrups

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

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Hook Length | Bar Bending Schedule

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

Total Length = L+2(9D)

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

2. Length of Straight Bar with Bends:-

Total Length = Length of Straight Portion + 2(Hook Length)

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Length of Straight Bar Formula | Bar Bending Schedule

3. Additional Length for Bent up or Crank Bar with Bends:-

The additional length (la) that is introduced in the simple, straight end-to-end length of a reinforcement bar due to being bent up at (Theta) say 30o to 60o, but it is generally 45o = l1 – l2 = la

Where,

bar bending schedule, bbs, bar bending schedule formula, bar bending schedule software, bar bending schedule of beam, bar bending schedule of slab, bar bending schedule of column, bar bending schedule of footing, bar bending schedule of staircase

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Fig: Hooks and bends in Reinforcement

Giving different values to clip_image005 respectively), we get different values of la, as tabulated below:

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length

 

Figure 2 presents the procedure to arrive at the length of hooks and the total length of a given steel reinforcement.

For 45 Deg | 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 45 degree with the length of 0.42D

D = Depth of Slab-Top Cover-Bottom cover

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length

 

4. Length for Extra Bars:-

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

5. Bend Hook Length Formula for Column:-

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]

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Hook Length Formula for Column | Bar Bending Schedule

6. 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]

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Overlap in Reinforcement Formula | Bar Bending Schedule

7. Hook’s Length Formula for Stirrups:-

Hook’s Length for Stirrups are mostly equal to 10d, Where d is dia of bar.

Rectangular Stirrups:

Rectangular Stirrups | Length of Stirrups = 2A + 2B + (2 x 10d)

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Cutting Length of Rectangular Stirrups | Bar Bending Schedule

Triangular Stirrups:

Triangular Stirrups | Length of Stirrups = 3H + (2 x 10d)

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Cutting Length of Triangular Stirrups | Bar Bending Schedule

Circular Stirrups:

Circular Stirrups | Length of Stirrups = (3.142 x Dia of Steel Ring) + (2 x 10d)

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Cutting Length of Circular Stirrups | Bar Bending Schedule

Diamond Stirrups:

Diamond Stirrups | Length of Stirrups = 4H + (2 x 10d)

Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Cutting Length of Diamond Stirrups | Bar Bending Schedule

Spiral Stirrups:

Spiral Stirrups | Length of Stirrups = Length of Spiral or Helix Bar = n x (C2 + P2)^0.5

where,

  • n = No. of Pitches = n = H/p + 1
  • C = 3.142 x d
  • P = Pitch or Spacing between spirals
Bar Bending Schedule Basic Formulas, BBS Formula, Hook Length, Cut Length of Straight Bar, Cut Length of Bend up Bar or Crank Bar, Length of Extra Bars, Hook's Length Formula for Stirrups, Lap Length
Cutting Length of Spiral Stirrups | Bar Bending Schedule

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Conclusion:

Full article on Bar Bending Schedule Basic Formulas | BBS Formula | Hook Length | Cut Length of Straight Bar | Cut Length of Bend up Bar or Crank Bar | Length of Extra Bars | Hook’s Length Formula for Stirrups | Lap Length. Thank you for the full reading of this article in “The Civil Engineering” platform in English. If you find this post helpful, then help others by sharing it on social media. If you have any question regarding article please tell me in comments.

24 COMMENTS

  1. Hi Sir you are very nice note provide all the civil engineer students and other construction realated people

    Thank you sir ji

  2. Engi Waseem Raja I apriciate you but is it bar bending is only civil engineer field? What about cotm engineer?

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