Basic Knowledge For Civil Engineer:
Following are few General Points for the Civil Engineer to remember to make the construction work easier while maintaining the quality of work.
Basics of Civil Engineering:
- Height of building = 3.15m.
- Height of Parapet wall should be 1m.
- Height of window = 2.1m.
- Minimum thickness of slab = 125mm.
- Minimum thickness of lintel = 15cm.
- Thickness of DPC = 2.5cm.
- Maximum diameter of the bars used for lapping is 36mm. Bars having more than this diameter are not allowed.
- Minimum diameter of bars used in Slab = 8mm.
- Minimum diameter of bars used in Column = 12mm.
- Minimum number of bars used in Square or Rectangular Column = 4 bars.
- Minimum number of bars used in Circular Column = 6 bars.
- Maximum diameter of bars used in Slab = 1/8 × thickness of slab.
- Maximum Chair spacing = 1m.
- Chairs minimum of 12 mm diameter bars to be used.
- Minimum diameter used for Dowels Bars is 12mm.
- Longitudinal reinfor should not be less than 0.8% and not be more than 6% of gross area of cross section.
- Binding wire required in steel reinfor is 8kg per MT.
- Weight of 1 cement bag = 50kg.
- 1 bag of cement = 1.25 cubit feet = 0.0347 cubic meter.
- No. of Cement Bags in 1m3 = 28.8 bags.
- Initial setting time of Cement = 30 minutes.
- Final setting time of Cement = 10hrs = 600 minutes.
- PH value of the water should not be less than 6.
- Riser of staircase = 150mm to 200mm.
- Tread of staircase = 250mm to 300mm.
- Angle of staircase = 25° to 40°.
- Tensile or Flexural strength of concrete = 0.7√fck.
- Modulus of elasticity of concrete = [Ec=5000√fck].
- Young’s modulus of steel = [Es=2×10^5 N/mm2].
- F.O.S for steel = 1.15.
- F.O.S for Concrete = 1.5.
- Standard size of Brick = 190mm×90mm×90 mm = 19cm×9cm×9cm.
- A good brick clay contains 20 to 30% of alumina, 50 to 60% of silica and the remaining constituents are Lime, Magnesia, Sodium, Potassium, Manganese and iron oxide.
- Colour of good brick is deep red, cherry or copper colored.
- Compressive
strength of bricks is 3.5
N/mm2.
- Maximum
water absorption of first
class brick is 15% of
its dry weight.
- The excess of silica in
the clay makes the brick
brittle and weak.
- Process of manufacturing
of bricks consists of Preparation
of brick clay, Moulding
bricks, Drying
of bricks and Burning
of bricks.
- Moulding
of bricks may be hand
moulding or machine
moulding.
- The burning of dry
bricks is done either in clamp or
in a kiln.
- The ingredients of ordinary cements are Lime,
Silica, Alumina, Calcium
sulphate, Iron
oxide, Magnesia, Sulphur
& Alkali’s.
- Ordinary
Portland cement consists
of 62 to 67% of Lime.
- The initial
setting time of ordinary Portland
cement should not be less than 30
minutes.
- The final
setting time of ordinary
Portland cement should not be more than 10
hours.
- Initial and Final setting time of cement is
determined by Vicat’s apparatus.
- The normal consistency of Portland
cement is about 25%.
- When concrete is
to be laid under water, Quick
setting cement is
used.
- Maximum free fall of concrete allowed to 1.50m.
- Test On Fresh Concrete
- Slump Test – Workability.
- Compacting Factor Test.
- Vee-Bee Test.
- Rebound (Schmidt) Hammer Test.
- Ultrasonic Pulse Velocity Test.
- M5 = 1 : 5 : 10
- M7.5 = 1 : 4 : 8
- M10 = 1 : 3 : 6
- M15 = 1 : 2 : 4
- M20 = 1 : 1.5 : 3
- M25 = 1 : 1 : 2
- M30 & above grade based on Design Mix.
