**Bar Bending Schedule** (BBS)

**Bar bending schedule** is a** table form data **in which various **diameters of steel**, the **shape of bending**, length of each **bent and straight** portions, **angles of bending,** the **total length **of each bar, and a **number of each type** of bar. **This information** is very useful for **site engineer** who is working **on-site **and while **preparing estimate** and bills of work.

**Read More:** **What Is Unit Weight of Steel | Unit Weight of Steel Bar Formula **

**How Is Bend Deducted In Bar Bending Schedules?**

The **Bend deductions** are very much **important while** calculating the **Bar Bending Schedule**. Basically, we **will be having **a thought that while** bending a bar** how much length of the bar **should be cut.**

**Many of** us think that we **require more than **the required **length** so that the bar** will come t**o its perfect length** after Bending**. But this is **not true.**

The **Reinforcement bars** which come to the market are of** Length 12 m.**

**So as the steel** has the **deformation property**, due to the elasticity the **length of the bar** increases while we **bend them.**

So the D**eductions **will be different for the **different bents b**ased on the **angles.**

**The Deductions are as follows:**

d is the diameter of the bar.

**1. For a 45-degree bend, the deduction is d.**

For ex**ample**, if the length of the bar is **12 m (assume),** the **diameter is 25 mm**. So for one bend, it is **deducted by d.**

i.e.

Cut**ting Length** = 12- d= 12- 0.025= 11.975 m.

Therefore only **11.975 m** bar is necessary to get a bar of** Length 12 m** after bending.

If we **bend a bar of 12 m** then the length of the** bar after bent will be**

= 12+ d= 12+0.025= **12.025 m** which will be more than required.

**2. Similarly for a 90-degree bend, the deduction is 2d.**

**For example, **if the** length of the bar is 12 m** (assume), the **diameter is 25 mm**. So for one bend, it is **deducted by 2d **as it is 90 degrees bend.

i.e.

**Cutting Length **= 12- 2d= 12- 2*0.025=** 11.95 m.**

**3. Similarly for 135-degree bend, the deduction is 3d.**

**For example,** if the **length** of the **bar is 12 m** (assume), the **diameter is 25 mm.** So for one b**end**, it is deducted by** 3d **as it is **135 degrees bend.**

i.e.

**Cutting Length** = 12- 3d= 12- 3*0.025= **11.925 m**.

**4. Similarly for a 180-degree bend, the deduction is 4d.**

**For** **example, **if the **length **of the** bar is 12 m** (assume), the** diameter is 25 mm.** So for one bend, it is **deducted by 4d **as it is **180 degrees bend **

**i.e.**

**Cutting Length** = 12- 3d= 12- 4*0.025=** 11.900 m.**

No**te:** For **n number of bends** there should be** n deductions** in the** original length** to get the **cutting length.**

**For Example,**

Le**ngth=12m**, Diameter=25mm,** bent angle= 90** degree & **no of bents are 2.**

Therefore **Cutting Length**= 12- 2*(2d)= 12- 2(2*0.025)= **11.9 m.**

No**te: **Practically in the **construction site** we will be** deducting only 2d** for a single bend **irrespective of the angle** (i.e. even though the angles are** 45 degrees**, 90 degrees,**135 degrees,** 180 degrees we will deduct only **2d for each bent)**.

Refer to **“IS:2502 Code of Practice for Bending and Fixing of bars”** for further information.

**Read More:** **Steel Quantity Calculation Excel Sheet**

**How to Prepare Bar Bending Schedule**

Let’s take the example of RCC slab reinforcement to calculate and prepare Bar Bending Schedule.

**RCC Slab Reinforcement Details**

- Main Bent Up Bars = 12 mm Dia. @ 150 c/c
- Distribution Steel Bars = 8 mm Dia. @ 180 c/c
- Side Cover = 50 mm
- Top & Bottom Cover = 20 mm
- All Hook’s = 90 Degree
- Bent Up = 45 Degree

SR. No. | Descriptions | No | Length | Breadth | Height | Quantity |

1 | 12 mm dia main Steel bars @ 150 mm c/c Alternate bent up. | |||||

L = Span Length + Wall Width(Right) + Wall Width (Left) + 2 x 9D (Hooks) – 2xCover L = 3 + 0.23 + 0.23 + (2 x 9 x 0.012) – (2 x 0.05) | ||||||

L = 3.58 m (Straight length without bent) | ||||||

Span = 4 + 0.23 + 0.23 – (2 x 0.05)= 4.36 m | ||||||

No. of Bars = (4.36/0.15) + 1 = 30 nos. | ||||||

Extra Length of Bent up: | ||||||

X – Value | ||||||

Extra Length = 0.45 X | ||||||

X = 0.12(Slab Thickness) – 2 x 0.02 (Top & Bottom Cover) – 0.012/2(Harf dia top) – 0.012/2( Half dia bottom) | ||||||

L = 3.58 + 0.45X L = 3.58 + 0.45 x 0.068 L = 3.61 m | 30 | 3.61 | @ | 0.89 | 96.38kg | |

(Note: In case of bent up bars are provided on both sides, we have to add 0.45 X twice in length) | ||||||

8 mm dia. Distribution steel @ 180 mm c/c | ||||||

Bars at Bottom: | ||||||

Hook Length = 9d = 9 x 0.008= 0.072 < 0.075 ( Mini. Hook length = 0.075) | ||||||

L = 4 + 0.23 + 0.23 + 2 x 0.075(Both side hook(9d) | ||||||

L = 4.51 m | ||||||

Width of Slab = 3 + 0.23 + 0.23 – 2 x 0.05 (Both Side Cover) = 3.36 m | ||||||

No. of Bars = (3.36 / 0.18) + 1 = 20 nos. | ||||||

Bars at Top: | ||||||

Width of Slab at one end for bent up at Top | ||||||

L= 0.23 + 0.45 – 0.068 – 0.05(cover) | ||||||

L = 0.562 m | ||||||

Nos. of Bars at one End:= (0.562/0.18) + 1 = 5 nos. | ||||||

Nos. of bars at both side = 2 x 5 = 10 | ||||||

Total Bars = 20 + 10 =30 | 30 | 4.51 | @ | 0.40 | 54.12 kg | |

**Read More: How to Calculate Steel Quantity from Drawing | BBS of Slab | Steel Quantity Calculation**

**Advantages of Bar Bending Schedule (BBS)**

1. When **Bar bending schedule** is available, **cutting and bending** of reinforcement can be done at **the factory **and transported **to the site. **This increases **faster execution** at the site **and reduces** construction** time **and cost due to **less requirement **of workers for bar bending. **Bar bending** also avoids the **wastage of steel** reinforcement **(5 to 10%) **and thus saves project costs.

2. Using a **bar bending schedule** when used for** Fe500,** saves **10% more steel **reinforcement compared t**o fe415.**

3. **It improves **the **quality control **at the site as **reinforcement** is provided as per **bar bending schedule **which is prepared using the **provisions of respective **detailing standard codes.

4.** It provides** a better **estimation** of **reinforcement steel** requirement for **each and every **structural **member **which can be **used to compute** overall reinforcement** requirement** for the entire project.

5. **It provides** better **stock management** for reinforcement.** Steel requirement** for the next phase of** construction** can be** estimated **with accuracy and **procurement** can be** done. **This prevents the **stocking of extra** steel **reinforcement** at the site for a** longer time**, pr**eventing corrosion of reinforcement in the **case of coastal areas.** It also prevents a** shortage of reinforcement for **ongoing work** by accurate estimation and** thus concrete **construction works can **proceed smoothly.**

6. **Bar bending schedule **is very much **useful** during auditing of **reinforcement** and provides **checks **on** theft and pilferage.**

7. **Bar bending schedule** can be used for **reinforcement cutting**, bending, and **making a **skeleton of a** structural member** before it can be** placed **at the required position. Other **activities** such as **excavation, **PCC, etc can proceed **parallel** with this **activity. **So, overall **project activity** management becomes** easy and reduces** the time of **construction.** It becomes **helpful** in preventing any* damages *due to construction

**time overrun.**

8. **It provides** benchmarks for **quantity and quality** requirements for** reinforcement** and con**crete works.**

9. **Bar bending schedule **provides the **steel quantity **requirement much **accurately** and thus** provides** an option to **optimize the design** in case of **cost overrun.**

10. It **becomes easy **for site engineers to** verify and approve** the bar bending and **cutting **length **during inspection** before **placement of **concrete with the use of** bar bending schedule **and helps in **better quality control.**

11. **It enables** easy **and fast **preparation of **bills of construction **works for clients and co**ntractors.**

12. The **quantity of reinforcement **to be used is **calculated **using **engineering formulas **and standard codes,** so there is no option** for approximate** estimation of steel reinforcement.**

13.** With the use of bar bending schedule,** mechanization of **cutting and bending** of reinforcement **can be done, **again reducing the **cost and time of project** and dependency on **skilled** labor requirement. It also **improves the reliability** of the accuracy of** bar cutting** and bending.

14. **When mechanized** bar **cutting and bending **is used, the **cost of reinforced** concrete work pe**r unit reduces** and helps in **cost optimization** of construction projects.

## FAQ:

### What Is Bar Bending Schedule?

**Bar bending schedule** is a** table form data **in which various **diameters of steel**, the **shape of bending**, length of each **bent and straight** portions, **angles of bending,** the **total length **of each bar, and a **number of each type** of bar.

### Bar Bending

**Bar bending** is a** table form data **in which various **diameters of steel**, the **shape of bending**, length of each **bent and straight** portions, **angles of bending,** the **total length **of each bar, and a **number of each type** of bar.

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