Most Important Point In This Article
What Is Bar Bending Schedule?
Bar bending is calculating steel quantity that calls bar bending schedule. The preparation of bar bending schedules is one of the final stages in any concrete design following the preparation and detailing of the working drawings.
Whereas the procedure is generally straightforward, it does require a certain amount of calculation which can readily be carried out with the aid of a computer program.
The program in this section calculates the lengths of reinforcing bars required and outputs a bar bending schedule table together with the total weight of steel.
Format of Bar Bending Schedule as per Code IS:2502-196
Location | Mark Designation | Size and Type | Number Per Set | Number of Sets | Total Number | Length | Shape ( All Dimensions Are in Accordance with This Standard Unless Otherwise Stated) |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) |
Column | C4 4R 25 N | MS Road 25 mm | 5 | 4 | 20 | 3000 | Straight |
Also, read: What Is Construction Contract | Types of Engineering Contracts | Percentage-Rate Contract
Bar Bending Schedule Use Formulas
1. Unit Weight of Steel Bars
Density = Mass (weight of steel) / Volume
Density = 7850 Kg / m^{3} Steel Bar
Mass = Weight of Steel
D = Dia of Bar in mm
L = Lenght of M
Volume = πD^{2} /4 x 1000 mm
Weight of Steel = (7850) x (πD^{2} x L/4 )
Weight of Steel = (7850/1000 x 1000 x 1000 ) x ( 3.14 D^{2} /4 )
Weight of Steel = (7850/1000 x 1000 x 1000 ) x ( 3.14 D^{2} x 1000 x/4 )
Weight of Steel = 0.00785 x 0.785 D^{2}
Weight of Steel =0.00616225 x D^{2}
Weight of Steel = (0.00616225/1) x (D^{2 }/1 )
Weight of Steel = D^{2} / 162.27 kg/m
Example
12 mm dia bar
Op-1
Weight of Steel = D^{2} / 162.27 mm
Weight of Steel = 12^{2} / 162.27 mm
Weight of Steel = 144 / 162.27 mm
Weight of Steel = 0. 8874 Kg/m
Op-2
Weight of Steel = (7850) x (π12^{2} x L/4 )
Weight of Steel = (7850/1000 x 1000 x 1000 ) x ( 3.14 12^{2} /4 )
Weight of Steel = (7850/1000 x 1000 x 1000 ) x ( 3.14 12^{2} x 1000 x/4 )
Weight of Steel = 0.00785 x 0.785 12^{2}
Weight of Steel =0.00616225 x 144
Weight of Steel = (0.00616225 x 144)
Weight of Steel = 0.8874 Kg/m
Also, read: Curing In Construction | Concrete Cure Time | Methods of curing
2. Plan Bar Length
L = Lenght of Steel
3. Bends and Hooks Forming End Anchorages ( As per IS 2502:1963 )
Hera
k in 2 in the case of Mild Steel conforming, ( As per IS 2502:1963, P-6, Note-1 )
k in 3 in the case of Medium Tensile Steel conforming, ( As per IS 2502:1963, P-6, Note-1 )
k in 4 in the case of Cold-worked Steel conforming, ( As per IS 2502:1963, P-6, Note-1 )
Most IMP (As per IS 2502:1963, P-6, Table-II, Note )
H = Hook allowance taken as 9d, 11d, 13d, and 17d for k values 2, 3, 4 and 6 respectively and rounded off to the nearest 5 mm, but not less than 75 mm.
B = Bend allowance is taken as 5d, 5.5d, 6d, and 7d for k values 2, 3, 4 and 6 respectively and rounded off to the nearest 5 mm, but not less than 75 mm.
4. Bar Bending Schedule Formulas as below (As per IS 2502:1963, P-8, Table-III )
Measurement of Bending Dimensions of Bars for Reinforced Concrete ( As per IS 2502:1963, P-8, Table-III )
Ref No. | Method of Measurement of Bending Dimensions | Approx Total Length of Bar (L) Measured Along Centre Line | Sketch and Dimensions to Be Given in Schedule | Approx Total Length of Bar (L) Measured Along Centre Line – Mild Steel | Approx Total Length of Bar (L) Measured Along Centre Line – Medium Tensile Steel |
Approx Total Length of Bar (L) Measured Along Centre Line – Cold-worked Steel |
A | 2A + E + C +9d + B | 2A + E + C +9d + 6d
2A + E + C +15d |
2A + E + C +9d + 7d
2A + E + C +16d |
2A + E + C +9d + 8d
2A + E + C +17d |
||
B | 4C + 24d | 4C + 24d | 4C + 24d | 4C + 24d | ||
C | 4C + 20d | 4C + 20d | 4C + 20d | 4C + 20d | ||
D | 2A + 3D + 22d | 2A + 3D + 22d | 2A + 3D + 22d | 2A + 3D + 22d | ||
E | 2A + 3D + 22d | 2A + 3D + 22d | 2A + 3D + 22d | 2A + 3D + 22d | ||
F | Where P is not greater than D/5 N = Number of complete and fractional turns D = Internal dia P = Pitch of helix d = Size of barN π (D + d) + 8d |
– | N π (D + d) + 8d | N π (D + d) + 8d | N π (D + d) + 8d | |
G | L + H | L+H = L + 4d+ d+2kd = L + 4d +4d +d = L + 9d |
L+H = L + 4d+ d+2kd = L + (2 x 3)d +4d +d = L + 11d |
L+H = L + 4d+ d+2kd = L + (2 x 4 )d +4d +d = L + 13d |
||
H | L + 2H | L+2H = L + 2 x (4d+ d+2kd) = L + ( 4d +4d +d) x2 = L + 18d |
L+2H = L + 2 x (4d+ d+2kd) = L + ((2 x 3)d +4d +d ) x 2 = L + 22d |
L+2H = L + 2 x (4d+ d+2kd) = L + ((2 x 4 )d +4d +d ) x 2 = L + 26d |
||
I | L + B | L + B = L +4d + kd = L +4d + 2d = L +6d |
L + B = L +4d + kd = L +4d + 3d = L +7d |
L + B = L +4d + kd = L +4d + 4d = L +8d |
||
J | L + 2B | L + 2B = L + 2x (4d + kd) = L +2 x (4d + 2d) = L +12d |
L + 2B = L + 2x (4d + kd) = L +2 x (4d + 3d) = L +14d |
L + 2B = L + 2x (4d + kd) = L +2 x (4d + 4d) = L +16d |
||
K | Where C is more than 3DA + C + E |
A + C + E | A + C + E | A + C + E | ||
L | If angle with horizontal is 45^{o} or less, and R is 12d or less
A + C + E + 2H |
A + C + E + 18d or L + 18d + C – √ ( C^{2} – D^{2} ) |
A + C + E + 22d or L + 22d + C – √ ( C^{2} – D^{2} ) |
A + C + E + 26d or L + 26d + C – √ ( C^{2} – D^{2} ) |
||
M | If angle with horizontal is 45^{o} or less, and R is 12d or less
A + C1 + C2 + E + F +2H |
A + C1 + C2 + E + F +18d or L +C1 + C2 + 18d – √ ( C1^{2} – D1^{2} ) – √ ( C2^{2} – D2^{2} ) |
A + C1 + C2 + E + F +22d or L +C1 + C2 + 22d – √ ( C1^{2} – D1^{2} ) – √ ( C2^{2} – D2^{2} ) |
A + C1 + C2 + E + F +26d or L +C1 + C2 + 26d – √ ( C1^{2} – D1^{2} ) – √ ( C2^{2} – D2^{2} ) |
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N | A + E – 0.5 R – d | A + E – 0.5 R – d | A + E – 0.5 R – d | A + E – 0.5 R – d | ||
O | A + E – 0.5 R – d + 2B | A + E – 0.5 R – d + 12d | A + E – 0.5 R – d + 14d | A + E – 0.5 R – d + 16d | ||
P | A + E – 0.5 R – d + 2H | A + E – 0.5 R – d + 18d | A + E – 0.5 R – d + 22d | A + E – 0.5 R – d + 26d | ||
Q | A + E + 1.5 D + 2H | A + E + 1.5 D + 18d | A + E + 1.5 D + 22d | A + E + 1.5 D + 26d | ||
R | If angle with horizontal is 45^{o} or less A + E |
A + E | A + E | A + E | ||
S | If angle with horizontal is 45^{o} or less R is 12d or less
A + E + 2H If the angle is greater than 45^{o} and R exceeds 12d, L to be calculated |
A + E + 18d | A + E + 22d | A + E + 26d | ||
T | If angle with horizontal is 45^{o} or less
A + B + C + H -2(R + d) If the angle is greater than 45^{o} and R exceeds 12d, L to be calculated |
A + B + C + 9d -2(R + d) | A + B + C + 11d -2(R + d) | A + B + C + 13d -2(R + d) | ||
U | L + 2H | L + 18d | L + 22d | L + 26d | ||
V | A + E + 2S + 2H + d | A + E + 2S + 18d + d | A + E + 2S + 22d + d | A + E + 2S + 26d + d | ||
W | A + E + 3S + 2d + B +H | A + E + 3S + 2d + 6d + 9d
A + E + 3S + 17d |
A + E + 3S + 2d + 7d + 11d
A + E + 3S + 20d |
A + E + 3S + 2d + 8d + 13d
A + E + 3S + 23d |
||
X | A + E + C + 2H – √ ( C^{2} – D^{2} ) -D | A + E + C + 18d – √ ( C^{2} – D^{2} ) -D | A + E + C + 22d – √ ( C^{2} – D^{2} ) -D | A + E + C + 26d – √ ( C^{2} – D^{2} ) -D | ||
Y | E + 2(A – D + C + H) | E + 2(A – D + C + 9d) | E + 2(A – D + C + 11d) | E + 2(A – D + C + 13d) | ||
Z | L + 2C + 2H | L + 2C + 18d | L + 2C + 22d | L + 2C + 26d | ||
AA | 2C + 2E1 + L + 2H | 2C + 2E1 + L + 18d | 2C + 2E1 + L + 22d | 2C + 2E1 + L + 26d | ||
AB | 2 (A + E) + 24d | 2 (A + E) + 24d | 2 (A + E) + 24d | 2 (A + E) + 24d | ||
AC | 2 (A + E) + 20d | 2 (A + E) + 20d | 2 (A + E) + 20d | 2 (A + E) + 20d | ||
AD | 2A + E + 28d | 2A + E + 28d | 2A + E + 28d | 2A + E + 28d | ||
AE | 2A + E + C +12d + B | 2A + E + C +12d + 6d
2A + E + C +18d |
2A + E + C +12d + 7d
2A + E + C +19d |
2A + E + C +12d + 8d
2A + E + C +20d |
||
AF | L | Straight | L | L | L |
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Jayanta says
If any reduce for having 6 bent in a bar of dia 10mm