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
- 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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