IMPORTANT TIPS FOR CIVIL ENGINEERS
STEEL
- Theoretical
weight of Steel - 7850 kg/ m3
- Weight
of reinforcement bars - D2 / 162 Kg/m
(D in mm)
- Weight
of reinforcement bars - D2 / 533 Kg/ft.
- Percentage
of steel in Columns - 0.08% - 6% of gross area
- Percentage
of steel in Beams - 1% - 2% of gross area
- Percentage
of steel in Slabs - 0.7% - 1% of gross area
- Main
bars in the slabs shall not be less than 8mm (HYSD) bars or 10mm (Plain
bars) and the distributors not less than 8mm and not more than 1/8 of slab
thickness
- Minimum
number of barsfor square column is 4nos. and 6 nos. for circular column
- Lapping
is not allowed for the bars having diameters more than 36 mm (above that
Couplers or welding only)
- Chairs
minimum of 12 mm dia bars should be used
- Chairs
spacing maximum 1 m or 1 no. per 1 Sqm
- For
Dowels, minimum of 12 mm dia. rods should be used
- Binding
wire required in reinforcements - 8 kg/MT
- "L"
for Column main rods in footing - Min. 300 mm
- Hook
for Stirrups - 9D for one side
COVER TO MAIN REINFORCEMENT
- Column:
40 mm (D>12mm)
- Column:
25 mm (D= 12mm)
- Beam:
25 mm
- Slab:
15 mm (or) not less than dia of the bar.
- Footing:
50 mm
- Sunshade
(Chajja): 25 mm
- Retaining
walls: 20 / 25 mm
CONCRETE
- Size
of Concrete testing Cubes - 150 x 150 x 150 mm
- Weight
of RCC - 2500 - 2700 Kg/ Cum
- Weight
of PCC - 2400 Kg/ Cum
- Concrete
cube is filled in - 3 Layers
- Slump
Cone is filled in - 4 Layers
- Thickness
of Shear wall - Min. 150 mm , Max. 400 mm
- Slope
of Staircase 25- 40 degree
- Minimum
thickness of slab - 125mm
- Dimension
Tolerance for Cubes - +/- 2 mm
- Free
fall of Concrete allowed - Max. 1.50 m
- Water
- Cement Ratio for different grades of Concrete shall not exceed 0.45 for
M20 and above and 0.5 for M10 & M15
- Slump
value required - For lightly Reinforced - 25- 75 mm and for heavily
reinforced - 75 - 100 mm
- pH
value of water should not be less than 6 for construction
- Cube
Samples required - Upto 30 Cum - 3 nos., Upto 50 Cum - 4
nos., Above 50 Cum - 4+1 no. of additional sample for each 50
Cum
- Compressive
Strength required for Concrete: In 3 days - 45%, 7 days - 67 -70%, 14 days
- 85%, 28 days - 100% +
- Clay
and Silt content in Sand should not exceed 3% by weight or 8-10% by
volume. For Crushed sand, Clay and silt content should not exceed 15% by
weight
- Target
strength of Concrete - 1.25 times design strength (Eg. For M40 - 1.25 x40)
- Cement
Requirement for M10 - 210 Kg, M20 - 320 Kg, M25 - 340 Kg, M30 - 380
Kg
- Water
absorption of Bricks - 12% to 20% of of its self-weight when submerged in
water for 24 hours
- Compressive
strength of Bricks - 105 Kg/ Cm2 or 10.5 N/mm2 for
I class bricks
- 70 Kg/ Cm2 or 7 N/mm2 for
II class bricks
- 35 Kg/ Cm2 or
3.5 N/mm2 minimum for bricks
- Compressive
strength of Fly ash Bricks - 90 to 100 Kg/ Cm2 or
9 to 10 N/mm2
- In
Soil filling, 3 samples should be taken in 100 Sqm for testing dry
density of soil by Core cutter test
DENSITY OF MATERIALS
- Weight
of Cement
- 1440 Kg /m3
- Weight
of Steel
- 7850 Kg/ m3
- Weight
of Bricks
- 1600 - 1920 Kg/ m3
- Weight
of Block work -
1920 Kg/ m3
- Weight
of Coarse aggregates - 2600 - 2900 Kg/m3
- Weight
of River sand or Fine aggregate - 1450 - 2100 Kg/m3
- Weight
of RCC
- 2310 - 2700 Kg/ m3
STRIPPING TIME ( De-Shuttering)
- 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 be refixed after removal)
- Spanning
up to 4.50m
: 7 days
- Spanning
over 4.50m
: 14
days
- Arches
spanning up to 6m
: 14 days
- Arches
spanning over 6m
: 21 days
CO-EFFICIENT FOR PAINTING
- Partly
paneled and glazed doors : 0.80 times the door or window area.
- Collapsible
gates
: 1.50
- Corrugated
sheet Steel doors : 1.25
- Rolling
shutters
: 1.10
- Flush
doors
: 1.20
- Fully
glazed doors
: 0.80
GENERAL
- Electrical
conduits shall not run in columns
- Earth
work excavation for basement above 3 m Should be stepped form
- Any
Back filling shall be compacted 95% of dry density at the optimum moisture
content and in layers not more than 200 mm for filling above structure and
300 mm for no structure
- Cement
shall be stored in dry places on a raised platform about 200 mm above
floor level and 300 mm away from walls. Bags to be stacked not more
than 10 bags high in such a manner that it is adequately protected from
moisture and contamination.
- Initial
setting time of Cement shall not be less than 30 minutes and Final setting
time shall not be more than 10 Hours
- Groove
cutting machine shall be used for chasing of walls for all electrical
conduits
- 4"
- 7" wide expanded metal mesh shall be fixed before plastering of all
conduit chasing in walls
- For
Column wall junctions & Beam wall junctions 4" wide expanded
metal mesh shall be fixed before plastering
- Anti
terminate treatment chemical Name is Chloropyrifos 20% . Diluting 5 Lit of
Chemical with 95 Lit of water and usage is 7.5 Sqm Per litre {Diluted}. To
Provide 1” Dia hole and Deep 1 Foot.
- One
cement bag=1.25 Cft
Thumb rule requirement of standard materials in high raised
building
- Steel
=3 to 5 kg / sft
- Cement
= 0.5bags/ sft
- RMC
= 0.05 m3/sft
- Block
=12.5 nos /sqm
Cement requirements in Plastering
- 200
mm in cm 1:6 - 0.124 Bags /sqm
- 200
mm in cm 1:4 - 0.206 bags/sqm
- 150
mm in cm 1:6 - 0.093 bags/sqm
- 150mm
in cm 1:4 - 0.144 bags/sqm
- 100
mm in cm 1:4 - 0.103 bags/sqm
- Ceiling
plastering - 0.11 bags/sqm
- Wall
plastering - 0.09 bags/sqm
- Rough
plastering - 0.09 bags/sqm
- Duct
plastering - 0.09 bags/sqm
- External
plastering - 0.175 bags/sqm
Cement requirements in PCC
- PCC
1: 4: 8 - 3.4 bags/cum
- PCC
1:5:10 - 2.52 bags/cum
- PCC
1:3:6 - 4.2 bags/cum
- PCC
1:2:4 - 6.02 bags/cum
Cement requirements in Brick work
- 230
mm brick work - 0.876 bags/cum
- 115
mm brick work - 0.218 bags/cum
Cement requirements in Flooring, Waterproofing
- VDF
100 mm thick - 0.82 bags/sqm
- Granolithic
flooring 40 mm - 0.35 bags/sqm
- Granolithic
flooring 20 mm - 0.28 bags/sqm
- Anti-skid
tiles laying - 0.28 bags/sqm
- Ceramic
tiles laying- 0.28 bags/sqm
- Vitrified
tile flooring - 0.28 bags/sqm
- Vitrified
tile dado - 0.27 bags/sqm
- Ceramic
dado - 0.27 bags/sqm
- Marble
flooring - 0.3 bags/sqm
- 100
mm heigh marble skirting - 0.027 bags/rmt
- Marble
cladding - 0.27 bags/sqm
- Terracota
tile flooring - 0.3 bags/sqm
- Mangalore
tile - 0.3 bags/sqm
- Door
frame fixing - 0.17 bags/sqm
- Water
proofing for sunken slab - 0.23 bags/sqm
- Water
proofing for walls - 0.23 bags/sqm
- Water
proofing for balcony/toilets - 0.65 bags/sqm
Conversion factors
- One
Sqm = 10.7639 Sft
- One
Cum = 35.314 Cft
- One
Cubic metre = 1000 litre
- One
Metre = 3.280 Feet
- One
Acres = 4046.873 Sqm = 43560.17 Sft =
4840.019 Yards
- One
Mile = 1609.344 metre
- One
Acre = 100 cent
- One
ground = 2400 Sft = 5.51 cent
- One
Mile = 8 Furlong
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