Wednesday, June 02, 2021

Important points for civil engineers

  1. Height of parapet wall should be  = 1 m.
  2. Thickness of DPC is                     = 2.5 cm.
  3. Height of building                         = 3.15m.
  4. Height of window                         = 2.1 m.
  5. One bag of cement                        = 1.25 ft3
  6. Weight of one cement bag is         = 50 kg.
  7. Minimum thickness of slab           = 125 mm(5")
  8. No. of cement bags/m3                  = 28.8 bags
  9. Lintel thickness                              = 15 mm
  10. Lintel is provided @ 2.4 m in case of brick wall.
  11. Minimum diameter of bars used in slab = 8 mm.
  12. Minimum diameter of bars used in column = 12mm.
  13. Minimum diameter of bars used in dowels =12mm
  14. Maximum diameter of bars in slab              = ( 1/8)  x thick of slab
  15. Maximum chair spacing                               = 1 meter
  16. Dimensional tolerance of cube                     =  2 mm
  17. Maximum water absorption of first class brick = 15 % of its dry weight
  18. Initial setting time of cement                             = 30 min
  19. Final setting time of cement                             = 10 hours
  20. DPR                                                                  = Detailed Project Report
  21. Unit weight: 
      1. RCC  = 25 kn/m3 = 25000 N/m3
      2. PCC  = 24 kn/m3 = 24000 N/m3
      3. Steel = 7850 kg/m3
      4. Brick = 1600 kg/m3 = 16 kn/m3
      5. Soil = 1800 kg/m3 = 18 kn/m3
  22. 1 Gallon = 3.78 liters
  23. Minimum no. of bars
    1. For square columns = 4 bars
    2. For circular columns = 6 bars
  24. Standard sand in India is obtained from Ennore Tamil Nandu.
  25. 1 Yard = 3 feet
  26. Weight of steel = D2/162.2 kg/m or D2/533 kg/ft
  27. Size of concrete testing cube = 150 mm x 150 mm x 150mm
  28. Concrete cube is filled in 3 layers.
  29. Slump cone is filled in 4 layers.
  30. Cement should be used with in the 3 months of manufacturing.
  31. Minimum thickness of shear wall = 150 mm.
  32. Maximum thickness of shear wall = 400 mm.
  33. (UTM) Universal testing machine is used for compression test of concrete & tensile test of steel reinforcement.
  34. Minimum curing period:
    1. 7 days   - Normal weather condition
    2. 10 days - Dry and hot weather condition
  35. Minimum percentage of steel in column = 0.8 % of gross area
    • Maximum percentage of steel in column = 6 % of gross area
  36. Nominal cover
    • Footing = 50mm
    • column = 40 mm
    • slab      = 20mm
    • beam    = 25 mm
  37. Least count:
    • Compass = 30' (30minutes)
    • Dump Level =5 mm
    • Auto level = 5mm
    • Theodolite = 20" (20 seconds)
  38. Air voids left in concrete is called as Honey Combing.
  39. The transverse reinforcement of column are called ties.
  40. The transverse reinforcement in beam are called stirrups.
  41. Minimum hook length =9D, example 9x 10 mm = 90mm
  42. No. of bricks in m3 = 500 bricks
  43. No. of bricks in 230 mm brick wall in 1 cubic meter = 496 bricks (including wastage)
  44. No. of bricks in 115 mm thick wall for 1 square meter = 56 bricks
  45. 8- 12 kg of binding wire is used per metric tonne of steel.
  46. Cement ingredients are burnt @ 1400degree c temp.
  47. 1BHK stands for 1 Bedroom , 1Hall, 1 kitchen.
  48. Short columns fail in crushing
  49. Long column fail in buckling
  50. Intermediate column can fail both in crushing and buckling.
  51. Tensile strength of concrete = 0.7(sqrt(fck)), fck = 20 N/mm2
  52. Modulus of elasticity of concrete =EC = 5000 sqrt(fck), fck =10,20,25,30 N/mm2
  53. Characteristic compression strength of concrete :
    • 150mm size cube tested @ 28 days (fck)
    • Strength of concrete below which not more than 5 % of test results are expected to fail.
  54. Ordinary concrete M10 = M20
  55. Standard concrete M25 = M55
  56. High strength concrete M60 = M80
  57. In mixer machine concrete should be mix for 2-3 minute
  58. Storage of cement:
    1. Cement should be stored in dry places.
    2. 200 mm away from floor (in a platform)
    3. 300 mm away from walls.
    4. Not more than 10 bags stocked.
    5. Away from the moisture of chemicals.
  59. Water absorption for bricks 1st class should be less than 20 percent.
  60. Water absorption is less than 5 percent for the building stones.
  61. Factor of safety for steel = 1.15
  62. Factor of safety for concrete = 1.5
  63. Young modulus of steel, ES = 2x 105 N/mm2
  64. Types of steel 
    1. Mild steel Fe250 N/mm2
    2. HYSD (High steel strength deformed bars)
      • Fe 415 N/mm2
      • Fy 500 N/mm2

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