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.

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Density of Materials:

MaterialDensity
Bricks1600 – 1920 kg/m3
Concrete block1920 kg/ m3
Reinforced concrete2310 – 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 MemberDe-shuttering time
For columns, walls, vertical form works16-24 hrs.
Soffit formwork to slabs3 days (props to be refixed after removal)
Soffit to beams props7 days (props to refixed after removal)
Beams spanning upto 4.5m7 days
Beams spanning over 4.5m14 days<
Arches spanning up to 6m14 days

Cube samples required for different quantity of concrete:

Quantity of ConcreteNo. of cubes required
1 – 5 m31 No’s
6 0 15 m32 No’s
16 – 30 m33 No’s
31 – 50 m34 No’s
Above 50 m34 + 1 No’s of addition of each 50 m3

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