Quiznetik

Design of Steel Structures | Set 5

1. For a cantilever beam of length continuous at the support and unrestrained against torsion at the support and free at the end, the effective length is equal to

Correct : D. l = 3L

2. Pick up the correct statement from the following:

Correct : D. All the above

3. 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

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

Correct : C. 40° to 70°

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

Correct : C. ± 0.7

6. 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

7. 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

8. 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)]

9. 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 %

10. The critical stress on a column for elastic buckling given by Euler's formula, is

Correct : A. fc = ²E/(I/r)²

11. 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

12. 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

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

Correct : C. 15 %

14. The mechanism method and the statical method give

Correct : B. Upper and lower bounds respectively on the strength ofstructure

15. The maximum spacing of vertical stiffeners is (Where d is the distance between flange angles)

Correct : C. 1.5 d

16. 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

17. 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

18. The range of economical spacing of trusses varies from

Correct : A. L/3 to L/5

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

Correct : C. 250

20. 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

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

Correct : B. 6 mm

22. 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

23. 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)}]

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

Correct : C. 140

25. An axial loaded column is supported on a slab base whose projection is 8 cm. If the intensity of pressure from concrete is 40 kg/cm2 and allowable bending stress in slab base is 1890 kg/cm2 , the thickness (t) of the slab base, is

Correct : B. t

26. 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

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

Correct : B. 13 %

28. 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)

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

Correct : D. All the above

30. The equivalent axial tensile load Pe, which produces an average axial tensile stress in the section equivalent to the combined stress due to axial tension P and bending M, at the extreme fibre of the section, is given by (where Z is the section modulus of the section).

Correct : A. Pe = P + MA/Z

31. 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

32. 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

33. 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

34. 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

35. 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

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

Correct : D. None of these

37. A 20 mm dia steel bar which is subjected to an axial tension of 2300 kg/cm2 produces a strain of cm. If Young's modulus of steel is 2.1 × 106kg/cm2, the bar is

Correct : A. In the elastic range

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

Correct : D. All the above

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

Correct : C. 15 %

40. 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

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

Correct : D. 20 mm

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

Correct : A. 180

43. 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

44. 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)}]

45. 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)