Points to be known for a Supervisor/Engineer at Site

        The responsibility of construction supervisor/Engineer 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.

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:

        1- Pile – 3″ or 75 mm

        2- Pile cap – 3″ or 75 mm

        3- Footing – 3″ or 75 mm

        4- Column below ground – 2½″ or 65 mm

        5- Column above ground – 1½″ or 40 mm

        6- Shear wall below ground – 2½″ or 65 mm

        7- Shear wall above ground – 1½″ or 40 mm

        8- Beam below ground – 2½″ or 65 mm

        9- Beam above ground – 1½″ or 40 mm

      10- Slab below ground – 2″ or 50 mm

      11- Slab above ground – ¾″ or 20 mm

      12- Stair – ¾″ or 20 mm

      13- Retaining wall’s earth face – 1½″ or 40 mm and opposite face: 1″ or 25 mm

      14- Door-window lintel – ¾″ or 20 mm

      15- Sunshade – ¾″ (20 mm).

2- Hook’s Length of Stirrup: 

The formula for calculating stirrup’s hook length is 6*D, where “D” is the diameter of bar. But stirrup’s hook length should not be less than 3″ or 7.62 cm.

3- End Hook for Longitudinal Bar of Beam: 

End hook is provided at both end of longitudinal bar. The length of hook should not be less than 12*D, where D 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 12*D, where D 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).

6- Anchorage Length of Cantilever Member: 

The anchorage length of main bar of a cantilever RCC member should not be less than 69*D, where D 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: 

Lap should be not provided larger than 36mm dia of steel.

10- Lap in compression zone: 

Steel should be lapping for compression zone with 50d, where (d) is dia of steel bar.

11- Lapping for Tension Steel:

Lapping should be lapping for tension zone with 40d, where (d) is dia of steel bar.

12- Maximum Lap in a Zone: 

Don’t use more than 50% lapping zone in any RCC structure.

13- Bent Up bar: 

Provide bent-up bar near at support of slab and beam.

14- Placing 1st Stirrup: 

1st stirrup of beam should be placed within 2″ from the support.

15- Standard Length of MS Bar: 

Full length of a deformed MS bar is about 40′.

16- 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.

17- Chair: 

MS bar for chair shouldn’t be less than 12 mm diameter.

18- Unit Weight of MS Bar:

        1- 8 mm ø bar – 0.12 kg/ft

        2- 10 mm ø bar – 0.19 kg/ft

        3- 12 mm ø bar – 0.27 kg/ft

        4- 16 mm ø bar – 0.48 kg/ft

        5- 20 mm ø bar – 0.75 kg/ft

        6- 25 mm ø bar – 1.25 kg/ft

Thanks and Regards,

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