Bar Bending Schedule of Column
The calculation of bar bending schedule of column given below:
The height of the column is 4 m and having a cross-sectional area is 300 x 400 mm and having a 40 mm of clear cover.Six bars are going to use has a dia of 16 mm.The 8 mm dia of stirrups is going to use @ 150mm and @200 mm at L/3.So calculate the cutting length bars and stirrups?
Given Data:
Height = 4 m
Cross section = 300 x 400 mm
Clear Cover = 40 mm
No of vertical bar = 6 no’s
Diameter of vertical bar = 16 mm
Diameter of Stirrup = 8 mm
Stirrups center to center spacing = @150 or @ 200 mm
BBS of Column = ?
Solution:
The Calculation was to proceed into two steps.
1.Vertical bar calculation
2.Cutting length of stirrups
Step 1: Vertical Bar Calculation
Length of 1 bar = H + Ld
Where
Ld = development length
H = Height of column
Length of 1 bar
= 4000 mm + 40d (d is dia of the bar)
= 4000 + 40 x 16
= 4000 + 640
= 4640 mm or 4.640 m
So the length of 1 vertical bar is 4.640 m and we have a total 6 number of bars,
Total length
= 6 x 4.640
= 27.84 m long vertical bar is required.
Step 2: Cutting the length of stirrups
Cross-sectional area column is 300 mm* 400mm
A is vertical cross-section area of the stirrup
B is a horizontal cross-section area of the stirrup
Calculation of A
= 300 – 2 x clear cover
= 300 – 2 x 40
= 300 – 80
= 220 mm
Calculation of B
= 400 – 2 x clear cover
= 400 – 2x 40
= 400 – 80
= 320 mm
No of stirrups
= 4000/3
= 1333.3mm or 1.33m
Formula = L/3 / spacing + 1
(No of stirrups in end zone)
= 1333.3 / 150
= 8.8 nos say 9 nos
There are total two zones of 150mm spacing and one zone of 200mm spacing
= 2 x 9
= 18 nos (at end zones)
At Mid Zones
= 1333.3 / 200
= 6.6 nos say 7 nos
Total no of stirrups
= 18 + 7
= 25 nos
Cutting Length of one stirrup
Formula:
= (2 x A) + (2 x B) + hook – bend
Cutting length
= (2 x A) + (2 x B) + 2 x 10d – 5 x 2d
Where
Hook = 10d
Bend = 5x 2d (because we have 5 bends in stirrup)
d = dia of bar
= (2 x 220) + (2 x 320) + 2 x 10 x 8 – 2 x 5 x 8
= 440 + 640 +160 – 80
= 1160 mm or 1.16 m
So we have a total 25 nos of stirrups are going to use,
Total length
= 25 x 1.16
= 29m long 8 mm bar
