Design of Concrete Structure MCQs

Design of Concrete Structure MCQs

 1. Along a hill road, a side drain is provided on. 

A. outer side of a spur curve. 
B. outer side of a re-entrant curve. 
C. outer side of both (a) and (b). 
D. inner side of both (a) and (b). 
Answer = inner side of both (a) and (b)

2. The property of the ingredients to separate from each other while placing the concrete is called____________?. 
A. segregation
B. compaction
C. shrinkage
D. bulking. 
Answer = segregation

3. Approximate value of shrinkage strain in concrete, is________________?. 
A. 0.003
B. 0.0003
C. 0.00003
D. 0.03. 
Answer = 0.0003

4. Workability of concrete is directly proportional to________________?. 
A. aggregate cement ratio
B. time of transit
C. grading of the aggregate
D. all of above. 
Answer = grading of the aggregate

5. The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by_______________?. 
A. tcr – rcs = tct
B. fcr>fcs>fc
C. fcr<fcs
D. fc5>fcr>fC. 
Answer = fcr>fcs>fc

6. Strength of concrete increases with________________?. 
A. increase in water-cement ratio
B. increase in fineness of cement
C. decrease in curing time
D. decrease in size of aggregate. 
Answer = increase in fineness of cement

7. As compared to ordinary portland cement, use of pozzuolanic cement_______________?. 
A. reduces workability
B. increases bleeding
C. increases shrinkage
D. increases strength. 
Answer = increases shrinkage

8. According to IS : 456 -1978, the modulus of elasticity of concrete Ec (in N/mm2) can be taken as______________?. 
A. Ec = = 5700
B. Ec = = 570
C. Ec = = 5700fck
D. Ec = where fck N/mm2 = 700 is the characteristic strength in. 
Answer = Ec = = 5700

9. The most commonly used admixture which prolongs the setting and hardening time is_______________?. 
A. gypsum
B. calcium chloride
C. sodium silicate
D. all of the above. 
Answer = gypsum

10. The strength of concrete after one year as compared to 28 days strength is about_______________?. 
A. 10 to 15% more
B. 15 to 20% more
C. 20 to 25% more
D. 25 to 50% more. 
Answer = 20 to 25% more

11. Admixtures which cause early setting, and hardening of concrete are called_______________?. 
A. workability admixtures
B. accelerators
C. retarders
D. air entraining agents. 
Answer = accelerators

12. Increase in the moisture content in concrete_________________?. 
A. reduces the strength
B. increases the strength
C. does not change the strength
D. all of the above. 
Answer = reduces the strength

13. The relation between modulus of rupturefcr and characteristic strength of concrete fck is given by_______________?. 
A. fcr=0.35Vf7
B. fcr=0.57f7
C. fcr=0.7Vf7
D. fcr=1.2Vf7 where fcr and fck are in N/mm2′. 
Answer = fcr=0.7Vf7

14. The approximate value of the ratio between direct tensile strength and flexural strength is_____________?. 
A. 0.33
B. 0.5
C. 0.75
D. 1.0. 
Answer = 0.5

15. Air entrainment in the concrete increases________________?. 
A. workability
B. strength
C. the effects of temperature variations
D. the unit weight. 
Answer = workability

16. Workability of concrete is inversely pro¬portional to______________?. 
A. time of transit
B. 'vater-cement ratio
C. the air in the mix
D. size of aggregate. 
Answer = time of transit

17. The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called________________?. 
A. segregation
B. bleeding
C. bulking
D. creep. 
Answer = bleeding

18. To determine the modulus of rupture, the size of test specimen used is_______________?. 
A. 150 x150 x500 mm
B. 100 x100 x700 mm
C. 150 x150 x700 mm
D. 100 x100 x500 mm. 
Answer = 150 x150 x700 mm

19. The percentage of voids in cement is approximately_______________?. 
A. 25%
B. 40%
C. 60%
D. 80%. 
Answer = 40%

20. Modulus of rupture of concrete is a measure of_______________?. 
A. flexural tensile strength
B. direct tensile strength
C. compressive strength
D. split tensile strength. 
Answer = flexural tensile strength

21. In order to obtain the best workability of concrete, the preferred shape of aggregate is_______________?. 
A. rounded
B. elongated
C. angular
D. all of the above. 
Answer = rounded

22. As compared to ordinary portland cement, high alumina cement has______________?. 
A. higher initial setting time but lower final setting time
B. lower initial setting time but higher final setting time
C. higher initial and final setting times
D. lower initial and final setting times. 
Answer = higher initial setting time but lower final setting time

23. Bulking of sand is maximum if moisture content is about____________?. 
A. 2 %
B. 4%
C. 6%
D. 10%. 
Answer = 4%

24. 1% of voids in a concrete mix would reduce its strength by about______________?. 
A. 5%
B. 10 %
C. 15%
D. 20%. 
Answer = 5%

25. Poisson's ratio for concrete_______________?. 
A. remains constant
B. increases with richer mixes
C. decreases with richer mixes
D. none of the above. 
Answer = increases with richer mixes

26. The factor of safety for______________?. 
A. steel and concrete are same
B. steel is lower than that for concrete
C. steel is higher than that for concrete
D. none of the above. 
Answer = steel is lower than that for concrete

27. The fineness modulus of fine aggregate is in the range of______________?. 
A. 2.0 to 3.5
B. 3.5 to 5.0
C. 5.0 to 7.0
D. 6.0 to 8.5. 
Answer = 2.0 to 3.5

28. The compressive strength of 100 mm cube as compared to 150 mm cube is always_______________?. 
A. less
B. more
C. equal
D. none of the above. 
Answer = more

29. If a beam fails in bond, then its bond strength can be increased most economi-cally by___________?. 
A. increasing the depth of beam
B. using thinner bars but more in number
C. using thicker bars but less in number
D. providing vertical stirrups. 
Answer = using thinner bars but more in number

30. If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called________________?. 
A. balanced beam
B. under-reinforced beam
C. over-reinforced beam
D. none of the above. 
Answer = over-reinforced beam

31. If the permissible stress in steel in tension is 140 N/mm2, then the depth of neutral axis for a singly reinforced rectangular balanced section will be___________________?. 
A. 0.35 d
B. 0.40 d
C. 0.45 d
D. dependent on grade of concrete also. 
Answer = 0.40 d

32. Minimum grade of concrete to be used in reinforced concrete as per IS:456-1978 is_____________?. 
A. M15
B. M20
C. M 10
D. M25. 
Answer = M15

33. Maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is_______________?. 
A. 28 liters
B. 30 liters
C. 32 liters
D. 34 liters. 
Answer = 32 liters

34. For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be________________?. 
A. 0.75-0.80
B. 0.80-0.85
C. 0.85 – 0.92
D. above 0.92. 
Answer = above 0.92

35. In case of hand mixing of concrete, the extra cement to be added is__________________?. 
A. 5%
B. 10%
C. 15%
D. 20%. 
Answer = 10%

36. The individual variation between test strength of sample should not be more than______________?. 
A. ±5% of average
B. ± 10% of average
C. ± 15% of average
D. ±20% of average. 
Answer = ± 15% of average

37. For walls, columns and vertical faces of all structural members, the form work is generally removed after_______________?. 
A. 24 to 48 hours
B. 3 days
C. 7 days
D. 14 days. 
Answer = 24 to 48 hours

38. For walls, columns and vertical faces of all structural members, the form work is generally removed after______________?. 
A. 24 to 48 hours
B. 3 days
C. 7 days
D. 14 days. 
Answer = 24 to 48 hours

39. One of the criteria for the effecvve width of flange of T-beam is bf =—+ bw +6Df 6 In above formula, l0 signifies_______________?. 
A. effective span of T-beam
B. distance between points of zero moments in the beam
C. distance between points of maximum moments in the beam
D. clear span of the T-beam. 
Answer = distance between points of zero moments in the beam

40. For a continuous slab of 3 m x 3.5 m size, the minimum overall depth of slab to satisfy vertical deflection limits is__________________?. 
A. 50 mm
B. 75 mm
C. 100 mm
D. 120 mm. 
Answer = 75 mm

41. According to IS : 456-1978, the fiexural strength of concrete is________________?. 
A. directly proportional to compressive strength
B. inversely proportional to compressive strength
C. directly proportional to square root of compressive strength
D. inversely proportional to square root of compressive strength. 
Answer = directly proportional to square root of compressive strength

42. According to IS: 456-1978, the maximum reinforcement in a column is_____________?. 
A. 2 %
B. 4%
C. 6 %
D. 8 %. 
Answer = 6 %

43. Which of the following statements is incorrect ?. 
A. Minimum cross sectional area of longitudinal reinforcement in a column is 0.8%
B. Spacing of longitudinal bars measured along the periphery of column should not exceed 300 mm
C. Reinforcing bars in a column should not be less than 12 mm in diameter
D. The number of longitudinal bars provided in a circular column should not be less than four. 
Answer = The number of longitudinal bars provided in a circular column should not be less than four

44. Minimum pitch of transverse reinforcement in a column is________________?. 
A. the least lateral dimension of the member
B. sixteen times the smallest diameter of longitudinal reinforcement bar to be tied
C. forty-eight times the diameter of transverse reinforcement
D. lesser of the above three values. 
Answer = lesser of the above three values

45. Minimum thickness of load bearing RCC wall should be_____________?. 
A. 50 mm
B. 100 mm
C. 150 mm
D. 200 mm. 
Answer = 100 mm

46. In reinforced concrete footing on soil, the minimum thickness at edge should not be less than______________?. 
A. 100 mm
B. 150 mm
C. 200 mm
D. 250 mm. 
Answer = 150 mm

47. The slab is designed as one way if the ratio of long span to short span is_____________?. 
A. less than 1
B. between 1 and 1.5
C. between 1.5 and 2
D. greater than 2. 
Answer = greater than 2

48. If the storey height is equal to length of RCC wall, the percentage increase in strength is_____________?. 
A. 0
B. 10
C. 20
D. 30. 
Answer = 10

49. Critical section for shear in case of flat slabs is at a distance of_______________?. 
A. effective depth of slab from periphery of column/drop panel
B. d/2 from periphery of column/capital/ drop panel
C. at the drop panel of slab
D. at the periphery of column. 
Answer = d/2 from periphery of column/capital/ drop panel

50. The average permissible stress in bond for plain bars in tension is_______________?. 
A. increased by 10% for bars in compression
B. increased by 25% for bars in compression
C. decreased by 10% for bars in compression
D. decreased by 25% for bars in compression. 
Answer = increased by 25% for bars in compression

51. Maximum distance between expansion joints in structures as per IS : 456 – 1978 is________________?. 
A. 20 m
B. 30 m
C. 45 m
D. 60 m. 
Answer = 45 m

52. A higher modular ratio shows____________?. 
A. higher compressive strength of con-crete
B. lower compressive strength of concrete
C. higher tensile strength of steel
D. lower tensile strength of steel. 
Answer = lower compressive strength of concrete

53. Ratio of permissible stress in direct compression and bending compression is______________?. 
A. less than 1
B. between 1 and 1.5
C. between 1.5 and 2.0
D. greater than 2. 
Answer = less than 1

54. In working stress design, permissible bond stress in the case of deformed bars is more than that in plain bars by_______________?. 
A. 10%
B. 20%
C. 30%
D. 40%. 
Answer = 40%

55. Half of the main steel in a simply supported slab is bent up near the support at a distance of x from the center of slab bearing where x is equal to________________?. 
A. 1/3
B. 1/5
C. 1/7
D. 1/10 where 1 is the span. 
Answer = 1/7

56. If the size of panel in a flat slab is 6m x 6m, then as per Indian Standard Code, the widths of column strip and middle strip are__________________?. 
A. 3.0 m and 1.5 m
B. 1.5 m and 3.0 m
C. 3.0 m and 3.0 m
D. 1.5 m and 1.5 m. 
Answer = 3.0 m and 3.0 m

57. The permissible diagonal tensile stress in reinforced brick work is_____________?. 
A. about 0.1 N/mm2
B. zero
C. 0.3 N/mm2 to 0.7 N/mm2
D. about 1.0 N/mm2. 
Answer = about 0.1 N/mm2

58. When shear stress exceeds the permissible limit in a slab, then it is reduced by____________?. 
A. increasing the depth
B. providing shear reinforcement
C. using high strength steel
D. using thinner bars but more in number. 
Answer = increasing the depth

59. The main reason for providing number of reinforcing bars at a support in a simply supported beam is to resist in that zone_________________?. 
A. compressive stress
B. shear stress
C. bond stress
D. tensile stress. 
Answer = bond stress

60. The limits of percentage p of the longitudinal reinforce-ment in a column is given by_____________?. 
A. 0.15% to 2%
B. 0.8% to 4%
C. 0.8% to 6%
D. 0.8% to 8%. 
Answer = 0.8% to 6%

61. The minimum cover to the ties or spirals should not be less than________________?. 
A. 15 mm
B. 20 mm
C. 25 mm
D. 50mm. 
Answer = 25 mm

62. Maximum percentage reinforcement in case of slabs is limited to___________________?. 
A. 2
B. 4
C. 6
D. 8. 
Answer = 4

63. The diameter of ties in a column should be_______________?. 
A. more than or equal to one fourth of diameter of main bar
B. more than or equal to 5 mm
C. more than 5 mm but less than one-fourth of diameter of main bar
D. more than 5 mm and also more than one-fourth of diameter of main bar. 
Answer = more than 5 mm and also more than one-fourth of diameter of main bar

64. The minimum diameter of longitudinal bars in a column is________________?. 
A. 6 mm
B. 8 mm
C. 12 mm
D. 16 mm. 
Answer = 12 mm

65. For the design of retaining walls, the minimum factor of safety against overturning is taken as_____________?. 
A. 1.5
B. 2.0
C. 2.5
D. 3.0. 
Answer = 2.0

66. The load carrying capacity of a helically reinforced column as compared to that of a tied column is about________________?. 
A. 5% less
B. 10% less
C. 5% more
D. 10% more. 
Answer = 5% more

67. Due to circumferential action of the spiral in a spirally reinforced column________________?. 
A. capacity of column is decreased
B. ductility of column reduces
C. capacity of column is decreased but ductility of column increases
D. both the capacity of column and ductility of column increase. 
Answer = both the capacity of column and ductility of column increase

68. For a slab supported on its four edges with corners held down and loaded uniformly, the Marcus correction factor to the moments obtained by Grashoff Rankine's theory_______________?. 
A. is always less than 1
B. is always greater than 1
C. can be more than 1
D. can be less than 1. 
Answer = is always less than 1

69. Modulus of elasticity of steel as per IS : 456-1978 shall be taken as______________?. 
A. 20 kN/cm2
B. 200 kN/cm2
C. 200kN/mm2
D. 2xl06N/cm2. 
Answer = 200kN/mm2

70. If the depth of neutral axis for a singly reinforced rectangular section is represented by kd in working stress design, then the value of k for balanced section_______________?. 
A. depends on as, only
B. depends on aCbC only
C. depends on both crst and acbc
D. is independant of both ast and acbc where d is the effective depth, ast is per-missible stress in steel in tension and ocbc is permissible stress in concrete in bend¬ing compression. 
Answer = depends on as, only

71. If nominal shear stress tv exceeds the design shear strength of concrete xc, the nominal shear reinforcement as per IS : 456-1978 shall be provided for carrying a shear stress equal to__________________?. 
A. xv
B. xc
C. xv – TC
D. Tv + Tc. 
Answer = xv – TC

72. For a reinforced concrete section, the shape of shear stress diagram is_______________?. 
A. wholly parabolic
B. wholly rectangular
C. parabolic above neutral axis and rectangular below neutral axis
D. rectangular above neutral axis and parabolic below neutral axis. 
Answer = parabolic above neutral axis and rectangular below neutral axis

73. In counterfort retaining walls, the main reinforcement in the stem at support is_______________?. 
A. not provided
B. provided only on inner face
C. provided only on front face
D. provided both on inner and front faces. 
Answer = provided only on inner face

74. In a counterfort retaining wall, the main reinforcement in the stem at mid span is provided on_______________?. 
A. front face only
B. inner face only
C. both front face and inner face
D. none of the above. 
Answer = front face only

75. A T-shaped retaining wall mainly conssits of_________________?. 
A. one cantilever
B. two cantilevers
C. three cantilevers
D. four cantilevers. 
Answer = three cantilevers

76. To minimise the effect of differential settlement, the area of a footing should be designed for______________?. 
A. dead load only
B. dead load + live load
C. dead load + fraction of live load
D. live load + fraction of dead load. 
Answer = dead load + fraction of live load

77. The design yield stress of steel according to IS: 456-1978 is_______________?. 
A. 0.37 fy
B. 0.57 fy
C. 0.67 fy
D. 0.87 fy. 
Answer = 0.87 fy

78. According to Whitney's theory, depth of stress block for a balanced section of a concrete beam is limited to_______________?. 
A. 0.43 d
B. 0.537 d
C. 0.68 d
D. 0.85 d. 
Answer = 0.537 d

79. As per Whitney's theory, the maximum moment of resistance of the balanced section of a beam of width b and effective depth d is given by_______________?. 
A. ^acybd2
B. ^acybd2
C. 0.185acybd2
D. 0.43acybd2 where acy is the cylinder compressive strength of concrete. 
Answer = ^acybd2

80. Due to shrinkage stresses, a simply supported beam having reinforcement only at bottom tends to_____________?. 
A. deflect downward
B. deflect upward
C. deflect downward or upward
D. none of the above. 
Answer = deflect downward

81. A beam curved in plan is designed for_______________?. 
A. bending moment and shear
B. bending moment and torsion
C. shear and torsion
D. bending moment, shear and torsion. 
Answer = bending moment, shear and torsion

82. In a spherical dome the hoop stress due to a concentrated load at crown is_______________?. 
A. compressive everywhere
B. tensile everywhere
C. partly compressive and partly tensile
D. zero. 
Answer = tensile everywhere

83. In prestressed concrete______________?. 
A. forces of tension and compression change but lever arm remains unchanged
B. forces of tension and compressions remain unchanged but lever arm changes with the moment
C. both forces of tension and compres-sion as well as lever arm change
D. both forces of tension and compres-sion as well as lever arm remain unchanged. 
Answer = forces of tension and compressions remain unchanged but lever arm changes with the moment

84. Normally prestressing wires are arranged in the_______________?. 
A. upper part of the beam
B. lower part of the beam
C. center
D. anywhere. 
Answer = lower part of the beam

85. Which of the following losses of prestress occurs only in pretensioning and not in post-tensioning ?. 
A. elastic shortening of concrete
B. shrinkage of concrete
C. creep of concrete
D. loss due to friction. 
Answer = elastic shortening of concrete

86. Which of the following has high tensile strength ?. 
A. plain hot rolled wires
B. cold drawn wires
C. heat treated rolled wires
D. all have same tensile strength. 
Answer = cold drawn wires

87. Stress strain curve of high tensile steel_______________?. 
A. has a definite yield point
B. does not show definite yield point but yield point is defined by 0.1% proof stress
C. does not show definite yield point but yield point is defined by 0.2% proof stress
D. does not show definite yield point but yield point is defined by 2% proof stress. 
Answer = does not show definite yield point but yield point is defined by 0.2% proof stress

88. Cube strength of controlled concrete to be used for pretensioned and post-tensioned work respectively should not be less than__________________?. 
A. 35 MPa and 42 MPa
B. 42 MPa and 35 MPa
C. 42 MPa and 53 MPa
D. 53 MPa and 42 MPa. 
Answer = 42 MPa and 35 MPa

89. Ultimate strength of cold drawn high steel wires_______________?. 
A. increases with increase in diameter of bar
B. decreases with increase in diameter of bar
C. does not depend on diameter of bar
D. none of the above. 
Answer = decreases with increase in diameter of bar

90. High carbon content in the steel causes_______________?. 
A. decrease in tensile strength but increase in ductility
B. increase in tensile strength but decrease in ductility
C. decrease in both tensile strength and ductility
D. increase in both tensile strength and ductility. 
Answer = increase in tensile strength but decrease in ductility

91. Prestress loss due to friction occurs________________?. 
A. only in post-tensioned beams
B. only in pretensioned beams
C. in both post-tensioned and preten-sioned beams
D. none of the above. 
Answer = only in post-tensioned beams

92. Most common method of prestressing used for factory production is________________?. 
A. Long line method
B. Freyssinet system
C. Magnel-Blaton system
D. Lee-Macall system. 
Answer = Long line method

93. The purpose of reinforcement in prestressed concrete is________________?. 
A. to provide adequate bond stress
B. to resist tensile stresses
C. to impart initial compressive stress in concrete
D. all of the above. 
Answer = to impart initial compressive stress in concrete

94. The maximum value of hoop compression in a dome is given by___________________?. 
A. wR / 4d
B. wR/2d
C. wR/d
D. 2wR/d. 
Answer = wR/2d

95. In a spherical dome subjected to concentrated load at crown or uniformly distributed load, the meridional force is always________________?. 
A. zero
B. tensile
C. compressive
D. tensile or compressive. 
Answer = compressive

96. In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively_______________?. 
A. compressive and tensile
B. tensile and compressive
C. both compressive
D. both tensile. 
Answer = tensile and compressive

97. The effect of creep on modular ratio is__________________?. 
A. to decrease it
B. to increase it
C. either to decrease or to increase it
D. to keep it unchanged. 
Answer = to increase it

98. The recommended value of modular ratio for reinforced brick work is______________?. 
A. 18
B. 30
C. 40
D. 58. 
Answer = 40

99. Select the correct statement?. 
A. Elastic modulus of high tensile steel is nearly the same as that of mild steel
B. Elastic modulus of high tensile steel is more than that of mild steel
C. Carbon percentage in high carbon steel is less than that in mild steel
D. High tensile steel is cheaper than mild steel. 
Answer = Elastic modulus of high tensile steel is nearly the same as that of mild steel

100. Select the incorrect statement?. 
A. Lean mixes bleed more as compared to rich ones
B. Bleeding can be minimized by adding pozzuolana finer aggregate
C. Bleeding can be increased by addition 'of calcium chloride
D. none of the above. 
Answer = none of the above

101. Select the incorrect statement?. 
A. The loss of prestress is more in pre-tensioning system than in post-tensioning system.
B. Pretensioning system has greater certainty about its durability.
C. For heavy loads and large spans in buildings or bridges, post-tensioning system is cheaper than pretensioning system
D. none of the above. 
Answer = none of the above
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