Vital Technical Terms Used In Reinforced Concrete Structures
A site supervisor should possess sound technical knowledge regarding construction to maintain proper quality of construction.
Given below, the details about some vital technical terms of reinforcement in RCC.
Concrete Cover for Reinforcement: Concrete cover alias clear cover refers to the distance among the surface of reinforcement nearest to the adjacent exterior surface of concrete member.
- The safeguarding of the steel from erosion.
- The movement of bond forces securely.
- Sufficient fire resistance.
Concrete cover varies based on the size and position of RCC member.
ALSO READ : SOME VITAL TECHNICAL TERMS IN CONSTRUCTION SITE
Get the values of concrete cover for different RCC members as follows:
- Pile – 3″ or 75 mm
- Pile cap – 3″ or 75 mm
- Footing – 3″ or 75 mm
- Column underneath ground – 2½” or 65 mm
- Column over ground – 1½” or 40 mm
- Shear wall underneath ground – 2½” or 65 mm
- Shear wall over ground – 1½” or 40 mm
- Beam underneath ground – 2½” or 65 mm
- Beam over ground – 1½” or 40 mm
- Slab underneath ground – 2″ or 50 mm
- Slab over 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)
Stirrup’s hook length: The formula 6db is used to work out the hook length of stirrup. Here “db” denotes the diameter of bar. The hook length should not be lower than 3".
End Hook for Longitudinal Bar of Beam: End hook is placed in both end of longitudinal bar. The length of hook should not be under 12db.
End Hook of Slab Top Reinforcement: End hook length of slab’s top bar shouldn’t be lower than 12db.
Bend for Vertical Bar of Column: Vertical bar of column is also known as longitudinal bar. Bend is given at one end of longitudinal bar. The bend should be 90° and length of bend should not remain under 18″ (450 mm).
Anchorage Length of Cantilever Member: The anchorage length of main bar of a cantilever RCC member should not remain under 69db.
Hook’s Angle of Stirrup: The hook angle of stirrup should be 135°.
End Hook’s Angle of Longitudinal Bar: End hook angle of longitudinal bars of column and beam should be 90°.
No Lap Bar: If the diameter of MS bar is greater than 36 mm, it should not be lapped.
Maximum Lap in a Zone: In one zone, greater than 50% of bars shouldn’t be lapped.
Lap in Tension: There should be no lapping in tension zone.
Placing 1st Stirrup: 1st stirrup of beam should be set within 2″ from the support.
Least Longitudinal Bar in a Column: A square-shape column should contain least 4 numbers of bars and a round column should contain least 6 numbers of bar.
Chair: MS bar for chair shouldn’t be lower than 12 mm diameter.
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
Standard Length of MS Bar: Total length of a deformed MS bar should be around 4o feet.
Required Binding Wire: To tie one ton of MS bar, 7 kg to 13 kg binding wire is necessary.
