17 Technical Terms about Reinforcement a Construction Supervisor Should Know

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

reinforcement, construction supervisor,

Reinforcement cover
We generally call it clear cover. Clear cover is the distance between reinforcement and outer face of RCC member. This distance varies depending on the RCC member size and location. Common clear cover value of different RCC members are given below:

1. Pile:- 3" (75 mm)

Pile cap:- 3" (75 mm)

Footing:- 3" (75 mm)

Column below ground: 2.5" (62 mm),

Column above ground: 1.5" (37 mm)

Shear wall below ground: 2.5" (62 mm)

Shear wall above ground: 1.5" (37 mm)

Beam below ground: 2.5" (62 mm),

Beam above ground: 1.5" (37 mm)

Slab below ground: 2" (50 mm)

Slab above ground:- 0.75" (20 mm)

Stair: 0.75" (20 mm)

Retaining wall's earth face: 1.5" (37 mm), opposite face: 1" (25 mm).

Door-window lintel: 0.75" (20 mm)

Sunshade: 0.75" (20 mm)

Hook and bend2. Stirrup's hook angle: 135 degree.

3. Stirrup hook length: 9D or, not below  3" (75 mm), (D= dia of bar),

4. End hook of beam reinforcement: 12D

5. End hook of slab top reinforcement: 12D

6. L bend for vertical reinforcement of column: not below 18" (450 mm).

7. Main steel anchorage length for cantilever is 69D.

8. Weight of steel
8 mm dia bar: 0.12 kg/rft,

10 mm dia bar: 0.19 kg/rft,

12 mm dia bar: 0.27 kg/rft,

16 mm dia bar: 0.48 kg/rft,

20 mm dia bar: 0.75 kg/rft,

25 mm dia bar: 1.25 kg/rft,

9. Standard steel bar length: 40 rft.

10. Weight of steel bars can be calculated by this formula, d2/162, result will be in kg/meter, where d is diameter of bar in millimeter.

Reinforcement placing
11. 1st stirrup of beam should be placed within 2" (50 mm) distance from support.

12. Steel bar larger than 36 mm shouldn't be lapped.

13. More than 50% of bars shouldn't be lapped in one place.

14. No lapping shouldn't be placed in tension zone.

15. For one ton steel bars 8 kg binding wire is required.

16. A square column should have minimum 4 numbers of bars and a round column should have minimum 6 numbers of bar.

17. Steel bar size for chair shouldn't be less than 12 mm diameter.

Over to you...
Can you point out anything else about reinforcement which a construction supervisor should know...