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USEFUL INFORMATION FOR CIVIL SITE ENGINEERS

USEFUL CIVIL ENGINEERING TIPS FOR SITE ENGINEERS:



1. GRADE OF CONCRETE:-

  • M5 - 1 : 4 : 8
  • M10 - 1 : 3 : 6
  • M15 - 1 : 2 : 4
  • M20 - 1 : 1.5 : 3
  • M25 - 1:1:2

2. CLEAR COVER TO MAIN REINFORCEMENT:-


  • Footings: 50 mm
  • Raft Foundation (Top) : 50 mm
  • Raft Foundation (Bottom): 75 mm
  • Raft Foundation (Side) : 75 mm
  • Beam: 25 mm
  • Strap Beam: 50 mm
  • Column :40 mm
  • Slab: 15 mm
  • flat Slab: 20 mm
  • Staircase: 15 mm
  • Retaining Wall: 20 – 25 mm
  • Water Retaining Structures: 2 0- 30 mm.
  • Maximum water absorption by bricks – 15%
  • Compressive strength of bricks – 3.5 N/mm2
  • Density Of Bricks- 1600-1920 Kg/m3
  • Minimum thickness of slab – 125 mm
  • Dimension tolerance for cubes – +2
  • Maximum free fall of concrete – 1.50 m
  • Lapping should not be used for the bars having larger dia than 36 mm.
  • Binding wire required for steel reinforcement – 8 kg per MT
  • 3 samples should be taken for every 100 m2 in core cutting test.
  • Maximum chair spacing – 1 m.
  • Minimum dia should be used in dowels rod – 12 mm.
  • Hook for strriups (one side) – 9D
  • No. of strriups = (clear span/spanning) + 1
  • Length of main steel in cantilever anchorage – 69D.
  • Minimum no. of bars in square column – 4
  • Minimum no. of bars in circular column – 6
  • Minimum dia of main bars and distributors in the slab – 8 mm.
  • Maximum dia of main bars and distributors in the slab – 1/8 of slab thickness.

All reinforcement should be free from mill scales, loose rust, and coats of paints, oil or any other substances.

3. SETTING TIME:

  • Initial setting time should not be less than 30 minutes.
  • Final setting time should not be greater than 10 hours.

4. REQUIRED CURING DAYS:

  • Super sulfate cement – 7 days
  • Ordinary portland cement – 10 days
  • Cement with minerals and admixtures – 14 days.

5. SLUMP VALUE (IS-456):

  • Lightly reinforced concrete: 25 – 75 mm.
  • Heavily reinforced concrete: 75 – 100 mm.
  • Trench fill : 100 – 150 mm ( for in-situ & tremie).

6. CUBE SAMPLES:

  •   1 – 5 m3 : 1 No.
  •   6 – 15 m3 : 2 No..
  •   16 – 30 m3 :3 No.
  •   31 -50 m3 : 4 No.
  •   Above 50 m3 : 4 + 1 no. of addition for each 50 m3.

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