Quiznetik

RCC Structures Design | Set 2

1. If the shear stress in a R.C.C. beam is

Correct : D. All the above

2. For a continuous floor slab supported on beams, the ratio of end span length and intermediate span length, is

Correct : D. 0.9

3. In a singly reinforced beam

Correct : C. Plane sectionstransverse to the centre line ofthe beam before bending remain plane after bending

4. The ratio of the breadth to effective depth of a beam is kept

Correct : B. 0.50

5. In a cantilever retaining wall without a heel slab

Correct : D. All the above

6. is the pre-stressed force applied to the tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is . The maximum stress in the beam, subjected to a maximum bending moment , is

Correct : C. f = (P/A) + (M/Z)

7. A T-beam behaves as a rectangular beam of a width equal to its flange if its neutral axis

Correct : A. Remains within the flange

8. For the design of a simply supported T-beam the ratio of the effective span to the overall depth of the beam is limited to

Correct : C. 20

9. A reinforced concrete cantilever beam is 3.6 m long, 25 cm wide and has its lever arm 40 cm. It carries a load of 1200 kg at its free end and vertical stirrups can carry 1800 kg. Assuming concrete to carry one-third of the diagonal tension and ignoring the weight of the beam, the number of shear stirrups required, is

Correct : C. 40

10. The width of the rib of a T-beam, is generally kept between

Correct : D. 1/3 to 2/3 of rib depth

11. A ribbed slab is provided for

Correct : D. All the above

12. To ensure that the hogging bending moment at two points of suspension of a pile of length L equals the sagging moment at its centre, the distances of the points of suspension from either end, is

Correct : B. 0.207 L

13. The stresses developed in concrete and steel in reinforced concrete beam 25 cm width and 70 cm effective depth, are 62.5 kg/cm2 and 250 kg/cm2 respectively. If m = 15, the depth of its neutral axis is

Correct : C. 30 cm

14. If the depth of actual neutral axis of a doubly reinforced beam

Correct : D. All the above

15. If the modularratio is , steel ratio is and overalldepth of a beam is , the depth ofthe critical neutral axis of the beam, is

Correct : B. [m/(m + r)] d

16. The maximum diameter of a bar used in a ribbed slab, is

Correct : D. 22 mm

17. A column is regarded as long column if the ratio of its effective length and lateral dimension, exceeds

Correct : B. 15

18. According to the steel beam theory of doubly reinforced beams

Correct : D. All the above

19. The breadth of a ribbed slab containing two bars must be between

Correct : B. 8 cm to 10 cm

20. The stem of a cantilever retaining wall which retains earth level with top is 6 m. If the angle of repose and weight of the soil per cubic metre are 30° and 2000 kg respectively, the effective width of the stem at the bottom, is

Correct : C. 53.5

21. If the diameter of the main reinforcement in a slab is 16 mm, the concrete cover to main bars is

Correct : D. 16 mm

22. Minimum spacing between horizontal parallel reinforcement of different sizes, should not be less than

Correct : B. One diameter ofthicker bar

23. For a number of columns constructed in a rcjw, the type of foundation provided, is

Correct : D. Strip

24. A singly reinforced concrete beam of 25 cm width and 70 cm effective depth is provided with 18.75 cm2 steel. If the modular ratio (m) is 15, the depth of the neutral axis, is

Correct : C. 30 cm

25. In testing a pile by load test, pile platform is loaded with one and half times the design load and a maximum settlement is noted. The load is gradually removed and the consequent rebound is measured. For a safe pile, the net settlement (i.e. total settlement minus rebound) per tonne of test load should not exceed

Correct : D. 25 mm

26. The diameter of main bars in R.C.C. columns, shall not be less than

Correct : D. 12 mm

27. If d is the diameter of a bar, ft is allowable tensile stress and fb, is allowable bond stress, the bond length is given by

Correct : A. ft.d/4fb

28. An intermediate T-beam reinforced with two layers of tensile steel with clear cover 13 cm encasted with the floor of a hall 12 metres by 7 metres, is spaced at 3 metres from adjoining beams and if the width of the beam is 20 cm, the breadth of the flange is

Correct : C. 176 cm

29. 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

Correct : C. 30 bardiameters

30. As the percentage of steel increases

Correct : B. Depth of neutral axis increases

31. The effective width of a column strip of a flat slab, is

Correct : B. Half the width of the panel

32. As per IS : 1343, total shrinkage for a pre-tensioned beam, is

Correct : D. 3.5 × 10-5

33. Dimensions of a beam need be changed if the shear stress is more than

Correct : C. 20 kg/cm2

34. Based on punching shear consideration, the overall depth of a combined footing under a column A, is

Correct : B. (Perimeter of column A × Safe punching stress)/(Load on column A + Upward pressure × Area of the column)

35. Pick up the correct statement from the following:

Correct : B. A pile is a slender member which transfers its load to the surrounding soil

36. In a combined footing if shear stress exceeds 5 kg/cm2 , the nominal stirrups provided are:

Correct : D. 12 legged

37. The weight of reinforced concrete, is generally taken as

Correct : C. 2400 kg/m3

38. If W is the load on a circular slab of radius R, the maximum circumferential moment at the centre of the slab, is

Correct : C. 3WR²/16

39. If is weight of a retainingwall and is the horizontal earth pressure, the factor of safety against sliding, is

Correct : C. 1.5

40. The effective span of a simply supported slab, is

Correct : B. Clear distance between the inner faces of the walls plus twice the thickness of the wall

41. In a beam the local bond stress Sb, is equal to

Correct : A. Shearforce/(Leaver arm× Total perimeter ofreinforcement)

42. A continuous beam shall be deemed to be a deep beam if the ratio of effective span to overall depth, is

Correct : A. 2.5

43. With usual notations the depth of the neutral axis of a balanced section, is given by

Correct : D. mc/t = n/(d - n)

44. Pick up the true statement from the following:

Correct : D. All the above

45. If the maximum shear stress at the end of a simply supported R.C.C. beam of 16 m effective span is 10 kg/cm2 , the length of the beam having nominal reinforcement, is

Correct : C. 8 m

46. If the length of a wall on either side of a lintel opening is at least half of its effective span L, the load W carried by the lintel is equivalent to the weight of brickwork contained in an equilateral triangle, producing a maximum bending moment

Correct : C. WL/6

47. The section of a reinforced beam where most distant concrete fibre in compression and tension in steel attains permissible stresses simultaneously, is called

Correct : D. All the above

48. The length of the lap in a compression member is kept greater than bar diameter x (Permissible stress in bar / Five times the bond stress) or

Correct : C. 24 bardiameters

49. The system in which high tensile alloy steel bars (silica manganese steel) are used as prestressing tendons, is known as

Correct : D. Lee-McCallsystem

50. An under-reinforced section means

Correct : D. Steel will yieldfirst

51. The angle of repose of a soil is the maximum angle which the outer face of the soil mass makes

Correct : A. With the horizontal

52. In a doubly-reinforced beam if and is the effective depth and is depth of critical neutral axis, the following relationship holds good

Correct : A. mc/t = n/(d - n)

53. A raft foundation is provided if its area exceeds the plan area of the building by

Correct : D. 50%

54. In favourable circumstances a 15 cm concrete cube after 28 days, attains a maximum crushing strength

Correct : D. 400 kg/cm2

55. If p1 is the vertical intensity of pressure at a depth h on a block of earth weighing w per unit p2 is

Correct : B. wh (1 - sin )/(1 + )

56. 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

Correct : D. Moment of the beam section about its neutral axis

57. According to I.S.: 456, 1978 the thickness of reinforced concrete footing on piles at its edges, is kept less than

Correct : B. 30 cm

58. An R.C.C. beam of 25 cm width and 50 cm effective depth has a clear span of 6 metres and carries a U.D.L. of 3000 kg/m inclusive of its self weight. If the lever arm constant for the section is 0.865, the maximum intensity of shear stress, is

Correct : A. 8.3 kg/cm2

59. The percentage of minimum reinforcement of the gross sectional area in slabs, is

Correct : C. 0.15 %

60. If the permissible compressive stress for a concrete in bending is C kg/m2 , the modular ratio is

Correct : C. 2800/3C

61. An R.C.C. beam not provided with shear reinforcement may develop cracks in its bottom inclined roughly to the horizontal at

Correct : C. 45°

62. Cantilever retaining walls can safely be used for a height not more than

Correct : D. 6 m

63. The maximum area of tension reinforcement in beams shall not exceed

Correct : C. 4 %

64. The width of the flange of a T-beam should be less than

Correct : D. Least of theabove

65. For a circular slab carrying a uniformly distributed load, the ratio of the maximum negative to maximum positive radial moment, is

Correct : B. 2

66. According to I.S. : 456 specifications, the safe diagonal tensile stress for M 150 grade concrete, is

Correct : A. 5 kg/cm2

67. The width of the flange of a T-beam, which may be considered to act effectively with the rib depends upon

Correct : D. All the above

68. The maximum shear stress (qmax) in a rectangular beam is

Correct : B. 1.50 timesthe average

69. If the sides of a slab simply supported on edges and spanning in two directions are equal, the maximum bending moment is multiplied by

Correct : D. 0.5

70. If K is a constant depending upon the ratio of the width of the slab to its effective span l, x is the distance of the concentrated load from the nearer support, bw is the width of the area of contact of the concentrated load measured parallel to the supported edge, the effective width of the slab be is

Correct : B. Kx (1 - x/l) + bw

71. The length of the straight portion of a bar beyond the end of the hook, should be at least

Correct : D. Seventimes the diameter

72. If the maximum bending moment of a simply supported slab is M Kg.cm, the effective depth of the slab is (where Q is M.R. factor)

Correct : D. (M/100Q)

73. If is the overall height of a retaining wall retaining a surcharge, the width of the base slab usually provided, is

Correct : D. 0.7 H

74. If diameter of a reinforcement bar is d, the anchorage value of the hook is

Correct : D. 16d

75. As per I.S. 456 - 1978, the pH value of water shall be

Correct : C. Not less than 6

76. For M 150 mix concrete, according to I.S. specifications, local bond stress, is

Correct : B. 10 kg/cm2

77. The minimum cube strength of concrete used for a pre-stressed member, is

Correct : D. 350 kg/cm2

78. If d and n are the effective depth and depth of the neutral axis respectively of a singly reinforced beam, the lever arm of the beam, is

Correct : D. d - n/3

79. The weight of a foundation is assumed as

Correct : C. 10% of wall weight

80. An R.C.C. column of 30 cm diameter is reinforced with 6 bars 12 mm placed symmetrically along the circumference. If it carries a load of 40, 000 kg axially, the stress is

Correct : A. 49.9 kg/cm2

81. If the diameter of longitudinal bars of a square column is 16 mm, the diameter of lateral ties should not be less than

Correct : B. 5 mm

82. Design of R.C.C. cantilever beams, is based on the resultant force at

Correct : A. Fixed end

83. In a combined footing if shear stress does not exceed 5 kg/cm2 , the nominal stirrups provided are

Correct : B. 8 legged

84. The maximum shear stress (q) in concrete of a reinforced cement concrete beam is

Correct : A. Shearforce/(Lever arm×Width)

85. An R.C.C. column is treated as long if its slenderness ratio is greater than

Correct : D. 50

86. The thickness of base slab of a retaining wall generally provided, is

Correct : D. Width of the stem at the bottom

87. Design of R.C.C. simply supported beams carrying U.D.L. is based on the resultant B.M. at

Correct : B. Mid span

88. If the maximum shear stress at the end of a simply supported R.C.C. beam of 6 m effective span is 10 kg/cm2 , the share stirrups are provided for a distance from either end where, is

Correct : C. 150 cm

89. Distribution reinforcement in a simply supported slab, is provided to distribute

Correct : D. All the above

90. Distribution of shear intensity over a rectangular section of a beam, follows:

Correct : C. A parabolic curve

91. In a singly reinforced beam, if the permissible stress in concrete reaches earlier than that in steel, the beam section is called

Correct : B. Over reinforced section

92. If the size of a column is reduced above the floor, the main bars of the columns, are

Correct : D. All the above

93. The minimum number of main steel bars provided in R.C.C.

Correct : D. All the above

94. If T and R are tread and rise respectively of a stair, then

Correct : A. 2R + T =60

95. For stairs spanning l metres longitudinally between supports at the bottom and top of a flight carrying a load w per unit horizontal area, the maximum bending moment per metre width, is

Correct : D. wl²/16

96. In a singly reinforced beam, the effective depth is measured from its compression edge to

Correct : B. Tensile reinforcement

97. Though the effective depth of a T-beam is the distance between the top compression edge to the centre of the tensile reinforcement, for heavy loads, it is taken as

Correct : C. 1/12th of thespan

98. On piles, the drop must be at least

Correct : C. 120 cm

99. Steel beam theory is used for

Correct : C. Doubly reinforced beams ignoring compressive stress inconcrete

100. In a pre-stressed beam carrying an external load W with a bent tendon is having angle of -stressed load P. The net downward load at the centre is

Correct : D. W - 2P