rcc structures design MCQs – Page 2

Practise focused rcc structures design questions with marked answers for exam preparation and subject revision.

rcc structures design Mcqs
51. If the permissible compressive and tensile stresses in a singly reinforced beam are 50 kg/cm2 and 1400 kg/cm2 respectively and the modular ratio is 18, the percentage area At of the steel required for an economic section, is__________________?
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A. 0.50%

52. is the pre- stressed force applied to tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is . The minimum stress on the beam subjected to a maximum bending moment is________________?
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A. f = (P/A) (Z/M)

B. f = (P/A) (M/Z)

C. f = (P/A) (M/6Z)

D. f = (A/P) (M/Z)

53. Pick up the incorrect statement from the following: Tensile reinforcement bars of a rectangular beam_______________?
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A. Are bent up at suitable places to serve as shear reinforcement

B. Are bent down at suitable places to serve as shear reinforcement

C. Are curtailed if not required to resist the bending moment

D. Are maintained at bottom to provide at least local bond stress

54. Thickened part of a flat slab over its supporting column, is technically known as_____________?
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A. Drop panel

B. None of these

C. Top of the column

D. Column head

55. If q is the punching shear resistance per unit area a, is the side of a square footing for a column of side b, carrying a weight W including the weight of the footing, the depth D. of the footing from punching shear consideration, is____________________?
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A. D = W (a b)/4abq

56. An R.C.C. lintel is spanning an opening of 2 m span in a brick wall. The height of the roof is 2.9 m above the floor level and that of the opening is 2.1 m above the floor level. The lintel is to be designed for self weight plus_______________?
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A. UDL of wall

B. UDL of wall + load from the roof

C. Triangular load + load from the roof

D. Triangular load of the wall

57. Side face reinforcement shall be provided in the beam when depth of the web in a beam exceeds_____________?
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A. 120 cm

B. 100 cm

C. 50 cm

D. 75 cm
58. For M 150 grade concrete (1:2:4) the moment of resistance factor is_________________?
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A. 8.50

B. 5.8

C. 7.5

D. 0.87

59. A very comfortable type of stairs is_______________?
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A. Dog legged

B. Straight

C. Open newel

D. Geometrical

60. For a ribbed slab______________?
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A. Width of the rib shall not be less than 7.5 cm

B. Clear spacing between ribs shall not be greater than 4.5 cm

C. Overall depth of the slab shall not exceed four times the breadth of the rib

D. All the above
61. In a pre-stressed member it is advisable to use________________?
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A. High strength concrete and high tensile steel

B. Low strength concrete but high tensile steel

C. High strength concrete only

D. Low strength concrete only

62. Long and short spans of a two way slab are l and l and load on the slab acting on strips parallel to lx and ly be wx and wy respectively. Accordingy to xRankine Grashoff theory___________________?
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A. (wx/wy) = (ly/lx)

B. None of these

C. (wx/wy) = (ly/lx)4

D. (wx/wy) = (ly/lx)

63. If the length of a combined footing for two columns l metres apart is L and the projection on the left side of the exterior column is x, then the projection y on the right side of the exterior column, in order to have a uniformly distributed load, is (where is the distance of centre of gravity of column loads______________?
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A. y = L/2 (l + )

B. y = L/2 + (l

C. y = L (l ) )

D. y = L/2 (l )
64. carrying a uniformly distributed load per metre length is suspended at two A pile of length points, the maximum, B.M. at the centre of the pile or at the points of suspension, is_________________?
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A. WL/16

B. WL/47

C. WL/8

D. WL/24

65. The minimum head room over a stair must be_______________?
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A. 200 cm

66. The Youngs modulus of elasticity of steel, is__________________?
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A. 250 KN/mm2

B. 150 KN/mm2

C. 275 KN/mm2

D. 200 KN/mm2

67. the column head support a flat slab, is generally kept The diameter of_____________?
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A. 5.0 cm larger than the diameter of the column

B. 4.0 cm larger than the diameter of the column

C. 0.25 times the diameter of the column

D. 0.25 times the span length
68. For initial estimate for a beam design, the width is assumed__________________?
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A. 1/15th of span

B. 1/25th of span

C. 1/20th of span

D. 1/30th of span
69. If the shear stress in a R.C.C. beam is_______________?
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A. Equal or less than 5 kg/cm2, no shear reinforcement is provided

70. The percentage of minimum reinforcement of the gross sectional area in slabs, is________________?
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A. 0.15 %

B. 0.10%

C. 0.18%

D. 0.12%

71. If W is the load on a circular slab of radius R, the maximum circumferential moment at the centre of the slab, is________________?
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A. WR/16

B. 3WR/16

C. Zero

D. 2WR/16

72. If P kg/m2 is the upward pressure on the slab of a plain concrete footing whose projection on either side of the wall is a cm, the depth of foundation D is given by________________?
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A. D = 0.00775 aP

B. D = 0.07775 aP

C. D = 0.775 Pa

D. D = 0.0775 aP

73. A raft foundation is provided if its area exceeds the plan area of the building by______________?
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A. 50 %

B. 40%

C. 20%

D. 10%

74. The amount of reinforcement for main bars in a slab, is based upon___________________?
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A. Maximum bending moment

B. Minimum bending moment

C. Minimum shear force

D. Maximum shear force

75. [A + (m 1)ASC] known as equivalent concrete area of R.C.C. is given by______________?
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A. Ultimate load method

B. Load factor method

C. None of these

D. Modular ratio method
76. The ratio of the breadth to effective depth of a beam is kept_______________?
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A. 0.7

B. 0.75

C. 0.50

D. 0.25

77. The reinforced concrete beam which has width 25 cm, lever arm 40 cm, shear force 6t/cm2, safe shear stress 5 kg/cm2 and B.M. 24 mt________________?
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A. Is over safe in shear

B. Is safe in shear

C. Needs redesigning

D. Is unsafe in shear
78. The allowable tensile stress in mild steel stirrups, reinforced cement concrete, is_______________?
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A. 190 kg/cm2

B. 1400 kg/cm2

C. 230 kg/cm2

D. 260 kg/cm2

79. In a singly reinforced beam, if the permissible stress in concrete reaches earlier than that in steel, the beam section is called________________?
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A. Over reinforced section

B. Critical section

C. Under-reinforced section

D. Economic section

80. Cantilever retaining walls can safely be used for a height not more than_______________?
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A. 3 m

B. 5 m

C. 4 m

D. 6 m
81. According to I.S. 456, 1978 the thickness of reinforced concrete footing on piles at its edges, is kept less than______________?
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A. 75 cm

B. 30 cm

C. 20 cm

D. 40 cm

82. As per I.S. 456 1978, the pH value of water shall be_______________?
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A. Equal to 6

B. Equal to 7

C. Not less than 6

D. Less than 6

83. per unit run exerted by the Total pressure on the vertical face of a retaining wall of height retained earth weighing per unit volume, is___________________?
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A. wh [(1 )/2(1 + sin )]

B. wh [(1 )/(1 + sin )]

C. wh [(1 )/(1 + sin )]

D. wh [(1 )/3(1 + sin )]

84. The anchorage value of a hook is assumed sixteen times the diameter of the bar if the angle of the bend, is___________________?
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A. All the above

B. 40

C. 30

D. 45

85. If the loading on a pre-stressed rectangular beam, is uniformly distributed, the tendon to be provided should be_______________?
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A. Straight below centroidal axis

B. Straight above centroidal axis

C. Parabolic with convexity downward

D. Parabolic with convexity upward

86. The advantage of reinforced concrete, is due to_______________?
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A. Economy because of less maintenance cost

B. Fire-resisting and durability

C. Monolithic character

D. All the above
87. Post tensioning system_______________?
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A. Is economical for large spans and is adopted now a days

B. Was widely used in earlier days

C. Is not economical and hence not generally used

D. None of these
88. The live load to be considered for an inaccessible roof, is______________?
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A. 200 kg/m2

B. 150 kg/cm 2

C. 75 kg/m2

D. Nil

89. The live load to be considered for an accessible roof, is________________?
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A. 75 kg/m3

B. 150 kg/m 2

C. Nil

D. 200 kg/cm 2

90. The length of lap in tension reinforcement should not be less than the bar diameter (actual tension / four times the permissible average bond stress) if it is more than_______________?
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A. 30 bar diameters

B. 36 bar diameters

C. 24 bar diameters

D. 18 bar diameters

91. If the effective length of a 32 cm diameter R.C.C. column is 4.40 m, its slenderness ratio, is_______________?
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A. 55

B. 40

C. 45

D. 50

92. Bottom bars under the columns are extended into the interior of the footing slab to a distance greater than____________?
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A. 24 diameters from the centre of the column

B. 42 diameters from the outer edge of the column

C. 42 diameters from the inner edge of the column

D. 42 diameters from the centre of the column

93. A part of the slab may be considered as the flange of the T-beam if__________________?
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A. All the above

B. It is built integrally with the beam

C. It is effectively bonded together with the beam

D. Flange has adequate reinforcement transverse to beam

94. A retaining wall and is the horizontal earth pressure, the factor of safety If is weight of against sliding, is_____________?
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A. 1.5

B. 1.25

C. 1

D. 2

95. For M 150 mix concrete, according to I.S. specifications, local bond stress, is_________________?
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A. 20 kg/cm2

B. 5 kg/cm2

C. 10 kg/cm 2

D. 15 kg/cm2

96. A pre-stressed concrete member__________________?
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A. Possesses internal stresses

B. Is made of reinforced concrete

C. Is made of concrete

D. Is stressed after casting

97. Pick up the incorrect statement from the following. The intensity of horizontal shear stress at the elemental part of a beam section, is directly proportional to__________________?
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A. Moment of the beam section about its neutral axis

B. Shear force

C. Distance of the C.G. of the area from its neutral axis

D. Area of the section

98. The breadth of a ribbed slab containing two bars must be between______________?
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A. 6 cm to 7.5 cm

B. 10 cm to 12 cm

C. 8 cm to 10 cm

D. 12 cm to 15 cm

99. For stairs spanning horizontally, the minimum waist provided is________________?
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A. 4 cm

B. 12 cm

C. 8 cm

D. 6 cm

100. A simply supported beam 6 m long and of effective depth 50 cm, carries a uniformly distributed load 2400 kg/m including its self weight. If the lever arm factor is 0.85 and permissible tensile stress of steel is 1400 kg/cm2, the area of steel required, is___________________?
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A. 17 cm2

B. 14 cm 2

C. 15 cm2

D. 16 cm2