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:
|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
<tr”>Arches spanning over 6m21 days
|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|
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|
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