Bar bending schedule for beam is the arrangement of bar as per length and diameter of bar.
The structural drawing of reinforced beam is prepared as per design load of the structure and it should follow the standard code of practice in respective country like IS 456 for India.
For preparation of bar bending schedule of beam we require the section plan of beam or longitudinal section drawing of RCC beam.
Here you can see a beam in which the steel bar is denoted by number of bar and dia of bar used in RCC beam.
As you see, the length of beam is not mentioned because the beam is situated in different location as per drawing plan.
Lets clear span of beam is 5.50 meter and section is 600×450 mm. Beam is situated on 600×600 mm column on both sides. You can choose as per your Beam.
Total length for beam reinforcement:
Length of beam is equal to the clear span of beam plus both column dimension.
L = 0.60+5.50+0.60 = 6.70 m
Length of reinforcement bar = Total length minus cover on both sides
Length of reinforcement bar = 6.70-0.03=0.03 = 6.64 m
We also consider the development length of bar for extra length of bar on both side.
1. Provide Development length:
Development length of beam is calculated as per IS 456
Here, in our beam the main bar is of dia 16mm and Fe415 (415 N/mm2) with M20 Grade of concrete.
So the Development length for 16mm deformed bar= 16*415/(4*1.2*1.6) = 865 mm = 0.865 m.
Development length of 20mm bar = 1080 mm = 1.08 m
Length of Bar = total length – cover + 2x development length
2. Provide HOOKS:
We can also provide the hook of U shape, which is x16 times of diameter of bar.
- Here hook length for 16mm bar = 16×16 = 256 mm
- Hook length for 20mm bar = 20×16 = 320 mm
So length of bar with hooks = 5.50+0.256 = 5.756 m
Lets bar bending schedule of beam with development length without hooks Stirrups/Ring of 10mm size = 0.54×0.39 m with bend hook Length of Ring = 2x(0.54+0.39+0.10) = 2.06
- 8 number of Main bar of 16 mm with 8.37m (0.865+6.64+0.865) with u shape = 8*8.37 = 66.96m
- so 16mm weight = 66.96*1.58 = 105.80 KG
- 3 number of bottom bar of 20mm with 3.56m with straight length = 3*3.56 = 10.68m
- 6 number of top extra bar of 20mm with 3.45m (1.08+2.37) with L shape = 6*3.45 = 20.70m
- so 20mm weight = (10.68+20.70)*2.47 = 77.50 KG
- 35 number of Stirrups/ring = 35×2.06 = 72.10 m
- so 10mm weight = 72.10*0.617 = 44.48 KG
Total Weight of Steel in beam = 105.80+77.50+44.48 = 227.78 KG