Following are a few general points for civil site engineers to make the construction work easier while maintaining the 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 is not less than 0.8% and more than 6% of gross C/S.
- Minimum bars for the square column is 4 No’s and 6 No’s for the 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.
- The minimum thickness of the slab is 125 mm.
- Dimension tolerance for cubes + 2 mm.
- Free fall of concrete is allowed a maximum of 1.50m.
- Lap slices not be used for bars 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.
- The 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 are required for different quantities 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 |