Updated March 17th, 2019
The responsibility of construction supervisor is huge. Quality of work mostly depend on the performance of site-supervisor. So, his role is very important for the quality of a project.
A supervisor must have enough technical knowledge about construction for ensuring quality of construction.
In this post I’ll share 17 technical terms about reinforcement in RCC.
17 Technical Terms about Reinforcement a Construction Supervisor Should Know
1. Concrete Cover for Reinforcement: We generally call it clear cover or concrete cover. Clear cover is the distance between rebar surface and the nearest outer surface of concrete member.
Concrete cover can vary depending on the size and location of rcc member.
The value of concrete cover for various rcc members are given below:
- Pile – 3″ or 75 mm
- Pile cap – 3″ or 75 mm
- Footing – 3″ or 75 mm
- Column below ground – 2½” or 65 mm
- Column above ground – 1½” or 40 mm
- Shear wall below ground – 2½” or 65 mm
- Shear wall above ground – 1½” or 40 mm
- Beam below ground – 2½” or 65 mm
- Beam above ground – 1½” or 40 mm
- Slab below ground – 2″ or 50 mm
- Slab above ground – ¾” or 20 mm
- Stair – ¾” or 20 mm
- Retaining wall’s earth face – 1½” or 40 mm and opposite face: 1″ or 25 mm
- Door-window lintel – ¾” or 20 mm
- Sunshade – ¾” (20 mm).
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2. Hook’s Length of Stirrup: The formula for calculating stirrup’s hook length is ‘6db”. Where “db” is the diameter of bar. But stirrup’s hook length should not be less than 3″.
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3. End Hook for Longitudinal Bar of Beam: End hook is providedat both end of longitudinal bar. The length of hook should not beless than 12db. Where db is the diameter of bar.
4. End Hook of Slab Top Reinforcement: End hook length of slab’s top bar shouldn’t be less than 12db. Where db is the diameter of bar.
5. Bend for Vertical Bar of Column: Vertical bar of column is also called longitudinal bar. Bend is provided at one end of longitudinal bar. The bend is 90° and length of bend should not less than 18″ (450 mm).
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6. Anchorage Length of Cantilever Member: The anchorage length of main bar of a cantilever rcc member should not be less than 69db. Where db is the diameter of bar.
7. Hook’s Angle of Stirrup: Stirrup’s hook angle is 135°.
8. End Hook’s Angle of Longitudinal Bar: End hook angle of longitudinal bars of column and beam is 90°.
9. No Lap Bar: MS bar larger than 36 mm diameter shouldn’t belapped.
10. Maximum Lap in a Zone: More than 50% of bars shouldn’t belapped in one zone.
11. Lap in Tension: No lapping should be placed in tension zone.
12. Placing 1st Stirrup: 1st stirrup of beam should be placed within 2″ from the support.
13. Minimum Longitudinal Bar in a Column: A square-shape column should have minimum 4 numbers of bars and a round column should have minimum 6 numbers of bar.
14. Chair: MS bar for chair shouldn’t be less than 12 mm diameter.
15. Unit Weight of MS Bar:
- 8 mm ø bar – 0.12 kg/ft
- 10 mm ø bar – 0.19 kg/ft
- 12 mm ø bar – 0.27 kg/ft
- 16 mm ø bar – 0.48 kg/ft
- 20 mm ø bar – 0.75 kg/ft
- 25 mm ø bar – 1.25 kg/rft
16. Standard Length of MS Bar: Full length of a deformed MS bar is about 40′.
17. Required Binding Wire: For binding one ton of MS bar 7 kg to 13 kg binding wire is required.
Do you want to add any term here in this post? Please share in comment below.