This document provides information and formulas for calculating bar bending schedules. It discusses hook length, bend length, overlap length, and how to prepare a bar bending schedule table. Formulas are given for calculating hook length, bend length for cranked and corner bars, and overlap length for tension and compression members. An example bar bending schedule is also shown for a sample RCC column, calculating the number of bars, cutting lengths, total bar lengths, and total steel weight required.

1. BAR BENDING SCHEDULE

2. Hook Length of Stirrups
• Hook Length = 9d (d is Diameter of the bar)
• 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

4. Bend Length
• (i) Bend Length calculation in
Cranked Bars:
• la = l1 – l2
• Tanθ = D/l2 ; Sinθ = D/l1
• Hence l1 = D/Sinθ and l2 = D/tanθ
• Therefore la = D/Sinθ – D/tanθ

5. Giving different θ values as 300 , 450, 600 results different additional length la values as below.

6. (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

7. Example Calculation considering
stirrup with the bends at corners:
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

10. Overlap Length /
Lap Length in
Reinforcement:-
• Overlap Length for compression
members (columns) = 50D
• The Overlap Length for tension
members (beams) = 40D
[D is the Diameter of the bar]

11. How to Prepare Bar Bending
Schedule
To understand clear, Here I am
considering the below
structural member RCC Column
and preparing a BBS for it

13. • 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

14. • 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

15. Bar Bending Formulas

16. Standard Bar Bending Shape Codes