Quiznetik

Design of Steel Structures | Set 3

1. If the thickness of plate to be connected by a rivet is 16 mm, then suitable size of rivet as per Unwin's formula will be

Correct : C. 24 mm

2. A major beam in a building structure, is known as

Correct : D. all the above

3. Angle of inclination of the lacing bar with the longitudinal axis of the column should preferably be between

Correct : C. 40° to 70°

4. In case of cantilever fillers, the ratio of the span L to depth d, should not exceed

Correct : C. 12

5. The internal pressure coefficient on walls for buildings with large permeability is taken as

Correct : C. ± 0.7

6. The gross diameter of a rivet is the diameter of

Correct : B. rivet after driving

7. The centrifugal force due to curvature of track is assumed to act on the bridge at a height of

Correct : C. 1.83 m above the rail level

8. The tensile strength of mild steel for bolts and nuts should not be less than

Correct : D. 44 kg/mm2

9. Efficiency of a riveted joint, having the minimum pitch as per IS : 800, is

Correct : C. 60 %

10. In double lacing, the thickness t of flat lacing is

Correct : C. t < 1/60 th length between inner end rivets

11. According to IS Specifications, the effective length of a column effectively held in position at both ends and restrained in direction at one end is taken as

Correct : B. 0.8 l

12. If M is the moment due to a couple in a bearing plate whose width is b and allowable bending stress is P, the thickness (t) of the bending plate of the column splice, is

Correct : B. t m/(b × p)]

13. The web crippling due to excessive bearing stress can be avoided by

Correct : C. increasing the length of the bearing plates

14. Allowable working stress corresponding to the slenderness ratio of double angles placed back to back and connected to one side of a gusset plate, is reduced to

Correct : D. 80 %

15. The number of seismic zones in which the country has been divided is

Correct : B. 5

16. Load factor is

Correct : C. always greater than factor of safety

17. When a tension member is made of four angles with a plate as a web, the allowance for holes is made as

Correct : C. one hole for each angle and two holes for the web

18. The effective length of a battened column is increased by

Correct : B. 10 %

19. To keep the intensity of bearing pressure between the column base and concrete compressive and to vary from zero to 2P/BL, the ratio of the moment M to the axial load P should be

Correct : D. l/6

20. The spans are considered approximately equal if the longest span does not exceed the shortest span by more than

Correct : C. 15 %

21. The mechanism method and the statical method give

Correct : B. upper and lower bounds respectively on the strength of structure

22. When two plates are placed end to end and are joined by two cover plates, the joint is known as

Correct : D. double cover butt joint

23. The strength of a riveted lap joint is equal to its

Correct : D. least of (a), (b) and (c)

24. Number of rivets required in a joint, is

Correct : D. load/rivet value

25. If the loaded length of span in meters of a railway steel bridge carrying a single track is 6 m, then impact factor is taken as

Correct : C. between 0.5 and 1.0

26. A riveted joint many experience

Correct : D. all the above

27. Diameter of a bolt hole is usually taken as

Correct : B. nominal diameter + 1.5 mm

28. The effective length of a double angle strut with angles placed back to back and connected to both the sides of a gusset plate, by not less than two rivets, is

Correct : C. 0.85 l

29. The range of economical spacing of trusses varies from

Correct : A. l/3 to l/5

30. Effective sectional area of a compression member is:

Correct : A. gross sectional area - area of rivet hole

31. The maximum slenderness ratio of a steel column, the design of which is governed by wind or seismic forces is

Correct : C. 250

32. In plastic analysis, the shape factor for circular sections, is

Correct : C. 1.697

33. The external wind pressure acting on a roof depends on

Correct : B. slope of roof

34. The failure of a web plate takes place by yielding if the ratio of the clear depth to thickness of the web, is less than

Correct : D. 82

35. The actual thickness of butt weld as compared to the thickness of plate is usually

Correct : A. more

36. The ratio of longitudinal stress to strain within elastic limit, is known as

Correct : A. modulus of elasticity

37. The slenderness ratio of lacing bars should not exceed

Correct : C. 145

38. In a fillet weld placed on the sides of the base, the metal experiences

Correct : D. all the above

39. For steel members not exposed to weather, the thickness of steel should not be less than

Correct : B. 6 mm

40. When a tension member consists of two channel sections, the allowance for rivet hole is made for two holes from

Correct : D. each web or one hole from each flange whichever is less

41. If a pair of angles placed back to back in tension are connected by one leg of each angle, the net effective area of the section, is

Correct : D. a + [b/{1 + 0.2 (b/a)}]

42. P E to be 25% of the computed value of P and E respectively, the minimum value of the factor of safety is

Correct : C. 1.67

43. A beam is defined as a structural member subjected to

Correct : B. transverse loading

44. The allowable stress in axial tension for rolled I-sections and channels, is taken as

Correct : B. 1500 kg/cm2

45. Secant formula for direct stress in compression, is applicable only for slenderness ratio upto

Correct : C. 140

46. A compression member consisting of angle sections may be a

Correct : D. all the above

47. The main advantage of a steel member, is:

Correct : D. all the above

48. A riveted joint may experience

Correct : D. all the above

49. IS : 800 - 1971 recommends that in a splice plate the number of rivets carrying calculated shear stress through a packing greater than 6 mm thick, is to be increased by 2.5% for every

Correct : C. 2.0 mm thickness of packing

50. To the calculated area of cover plates of a built-up beam, an allowance for rivet holes to be added, is

Correct : B. 13 %

51. If the moment of inertia of a section about its axis is and its effective sectional area is , its radius of gyration r about the axis, is

Correct : B. r i/a)

52. A structural member subjected to compressive stress in a direction parallel to its longitudinal axis, is generally known as

Correct : D. all the above

53. Live load

Correct : D. all the above

54. The maximum permissible slenderness ratio of a member carrying loads resulting from wind, is

Correct : C. 250

55. The average shear stress for rolled steel beam section, is

Correct : B. 945 kg/cm2

56. For a rectangular section, the ratio of the maximum and average shear stresses, is

Correct : A. 1.5

57. For the steel member exposed to weather and accessible for repainting, the thickness of steel should not be less than (accepting the webs of Indian Standard rolled steel joists and channels).

Correct : B. 6 mm

58. The permissible stress in bending for rolled steel I-beams and channels, is

Correct : D. 1650 kg/cm2

59. The distance measured along one rivet line from the centre of a rivet to the centre of adjoining rivet on an adjacent parallel rivet line, is called

Correct : C. staggered pitch

60. The effective length of a simply supported beam with ends restrained against torsion, and also the ends of compression flange partially restrained against lateral bending, is given by

Correct : B. l = 0.85 span

61. The permissible bearing stress in steel, is

Correct : B. 1890 kg/cm2

62. Strengths of a rivet in single shearing, in bearing and in tearing are 3425 kg, 4575 kg and 5025 kg respectively. If the load in the member is 35 tonnes, the number of rivets required, is

Correct : D. 13

63. The bending moment for filler joists at the middle of an intermediate span, is

Correct : D. wl²/12

64. A simply supported beam carrying a central load, will be safe in deflection if the ratio of its span to depth, is

Correct : B. < 24

65. When a load is transferred through one surface to another surface in contact, the stress is known as

Correct : D. none of these

66. If p and d are pitch and gross diameter of rivets, the efficiency ( ) of the riveted joint, is given by

Correct : C. = p - d/p

67. The slenderness ratio of a column is zero when its length

Correct : D. is between the points of zero moments

68. The maximum axial load which is just sufficient to keep a column in a small deflected shape, is called

Correct : D. all the above

69. Spans of continuous fillers are considered approximately equal if the longest span does not exceed the shortest span by more than

Correct : C. 15 %

70. The ratio of the span L of the filler joists to the depth d from the underside of the joist to the top of the structural concrete, should not exceed

Correct : C. 35

71. With a percentage increase of carbon in steel, decreases its

Correct : D. ductility

72. The allowable stress in axial tension is generally kept less if thickness of the member is more than

Correct : D. 20 mm

73. The maximum permissible slenderness ratio of compression member carrying dead and superimposed load, is

Correct : A. 180

74. Tacking rivets in compression plates not exposed to the weather, have a pitch not exceeding 300 mm or

Correct : C. 32 times the thickness of outside plate

75. A single angle in tension is connected by one leg only. If the areas of connecting and outstanding legs are respectively a and b, net effective area of the angle, is

Correct : B. a + [b/{1 + 0.35 (b/a)}]

76. If L is the overall length of a combined footing having A as its area, d being the distance between the centre of gravity of the base and centre of the base, the larger width b is

Correct : B. (a/l) + (6ad/l²)

77. Select the correct statement

Correct : C. Bolts are used as a temporary fastening whereas rivets are used as permanentfastenings

78. In a gusseted base, when the end of the column is machined for complete bearing on the base plate, then the axial load is assumed to be transferred to base plate

Correct : C. 50% by direct bearing and 50% through fastenings

79. If the floor is supported at or near the bottom but top chords of a bridge is not braced, then the bridge is called

Correct : C. Half through type

80. The elastic strain for steel is about

Correct : C. 1/12 of strain at the initiation of strain hardening and 1/200 of maximumstrain

81. In moment resistant connections, the moment resistance of riveted connection depends upon

Correct : C. Tension in rivets

82. The moment of the couple set up in a section of a beam by the longitudinal compressive and tensile force, is known as

Correct : B. Moment of resistance

83. The thickness of the web of a mild steel plate girder is less than d/200. If only one horizontal stiffener is used, it is placed at

Correct : C. 2/5th of the depth of the neutral axis from the compressionflange

84. The most commonly used sections in lateral system to carry shear force in built up columns, are

Correct : D. All the above

85. The bracing between two columns of a steel tank will be designed to resist

Correct : B. Horizontal, shear due to wind or earthquake + 2.5% of column loads

86. A beam may be designed as a cased beam if

Correct : D. All the above

87. In a built up beam actual bending compressive stress fbc is given by (when y1 is the distance of the edge of the beam from the neutral axis).

Correct : A. fbc = (M/Ixx) × y

88. If the thickness of a structural member is small as compared to its length and width, it is classified as

Correct : B. Two dimensional

89. Compression members composed of two channels back-to-back and separated by a small distance are connected together by riveting so that the minimum slenderness ratio of each member between the connections, does not exceed

Correct : A. 40

90. The connection of intermediate vertical stiffeners to the web, not subjected to external loads, shall be designed for a minimum shear force (kN/m) of (Where, t = the web thickness in mm and h = the outstand of stiffener in mm)

Correct : C. 125 t²/h

91. When the upper column does not provide full bearing area over lower column, the column splice is provided with the following assumption

Correct : D. All the above

92. For the economical design of a combined footing to support two equal column loads, the projections of beams in lower tier are kept such that bending moment under column is equal to

Correct : A. Bending moment at the centre of the beam

93. The allowable shear stress in the web of mild steel beams decreases with (Where 'h is thickness)

Correct : B. Increase in h/t ratio

94. On eccentrically loaded columns, the equivalent axial load may be obtained by

Correct : A. Adding the axial load, eccentric load, the product of the bending moment due to eccentric load and the appropriate bending factor

95. In a truss girder of a bridge, a diagonal consists of mild steel flat 4001.S.F. and carries a pull of 80 tonnes. If the gross-diameter of the rivet is 26 mm, the number of rivets required in the splice, is

Correct : C. 8

96. When the bolts are subjected to reversal of stresses, the most suitable type of bolt is

Correct : D. High strength bolt

97. The size of a butt weld is specified by the effective throat thickness which in the case of incomplete penetration, is taken as

Correct : D. 7/8 of the thickness of thinner part

98. In a built up section carrying a tensile force, the flanges of two channels are turned outward

Correct : C. To have greater lateral rigidity

99. The overlap of batten plates with the main members in welded connections should be more than

Correct : B. 4 t

100. Modified moment of inertia of sections with a single web, is equal to moment of inertia of the section about Y-Y axis at the point of maximum bending moment and is multiplied by the ratio of

Correct : C. Total area of flanges at the maximum bending moment to the corresponding area at the point of maximum bending moment