Points to remember for civil site engineers

Points to remember for civil site engineers

• 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.
• 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.
• 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.                

  Density of Materials

  Material	Density
  Bricks	1600 – 1920 kg/m3
  Concrete block	1920 kg/ m3
  Reinforced concrete	2310 – 2700 kg/ m3

  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

  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