IMPORTANT TIPS FOR SITE ENGINEERS

IMPORTANT TIPS FOR SITE ENGINEERS:

Following are the basic civil engineering tips you should be remembered while working on a construction site.

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

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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