Following are few general points to remember for civil site engineers to make the construction work easier while maintaining quality of construction.
- Lapping is not allowed for the bars having diameters more than 36 mm.
- Chair spacing maximum spacing is 1.00 m (or) 1 No per 1m2.
- For dowels rod minimum of 12 mm diameter should be used.
- Chairs minimum of 12 mm diameter bars to be used.
- Longitudinal reinforcement not less than 0.8% and more than 6% of gross C/S.
- Minimum bars for square column is 4 No’s and 6 No’s for circular column.
- Main bars in the slabs shall not be less than 8 mm (HYSD) or 10 mm (Plain bars) and the distributors not less than 8 mm and not more than 1/8 of slab thickness.
- Minimum thickness of slab is 125 mm.
- Dimension tolerance for cubes + 2 mm.
- Free fall of concrete is allowed maximum to 1.50m.
- Lap slices not be used for bar larger than 36 mm.
- Water absorption of bricks should not be more than 15 %.
- PH value of the water should not be less than 6.
- Compressive strength of Bricks is 3.5 N / mm2.
- In steel reinforcement binding wire required is 8 kg per MT.
- In soil filling as per IS code, 3 samples should be taken for core cutting test for every 100m2.
Density of Materials:
Material
|
Density
|
Bricks
|
1600 – 1920 kg/m3
|
Concrete block
|
1920 kg/ m3
|
Reinforced concrete
|
2310 – 2700 kg/ m3
|
Curing time of RCC Members for different types of cement:
Super Sulphate cement: 7 days
Ordinary Portland cement OPC: 10 days
Minerals & Admixture added cement: 14 days
De-Shuttering time of different RCC Members
RCC Member
|
De-shuttering time
|
For columns, walls, vertical form works
|
16-24 hrs.
|
Soffit formwork to slabs
|
3 days (props to be refixed after removal)
|
Soffit to beams props
|
7 days (props to refixed after removal)
|
Beams spanning upto 4.5m
|
7 days
|
Beams spanning over 4.5m
|
14 days
|
Arches spanning up to 6m
|
14 days
|
Arches spanning over 6m
|
21 days
|
Cube samples required for different quantity of concrete:
Quantity of Concrete
|
No. of cubes required
|
1 – 5 m3
|
1 No’s
|
6 0 15 m3
|
2 No’s
|
16 – 30 m3
|
3 No’s
|
31 – 50 m3
|
4 No’s
|
Above 50 m3
|
4 + 1 No’s of addition of each 50 m3
|