### Civil Engineering - Theory of Structures MCQs Part 3

1. If a concrete column 200 x 200 mm in cross-section is reinforced with four steel bars of 1200 mm2 total cross-sectional area. Calculate the safe load for the column if permissible stress in concrete is 5 N/mm2 and Es is 15 Ec

A.

264 MN

264 MN

B.

274 MN

274 MN

C.

284 MN

284 MN

D.

294 MN

294 MN

E.

None of these.

None of these.

**Answer Option C**

2. If normal stresses due to longitudinal and transverse loads on a bar are σ1 and σ2 respectively, the normal component of the stress on an inclined plane θ° to the longitudinal load, is

A.

σ1 sin θ x σ2 cos θ

σ1 sin θ x σ2 cos θ

B.

σ1 sin θ2 + σ2 cos2 θ

σ1 sin θ2 + σ2 cos2 θ

C.

D.

**Answer Option B**

3. A shaft subjected to a bending moment M and a torque T, experiences

A.

maximum bending stress =

maximum bending stress =

B.

maximum shear stress =

maximum shear stress =

C.

both (a) and (b)

both (a) and (b)

D.

neither (a) nor (b)

neither (a) nor (b)

**Answer Option C**

4. In the truss shown in given figure the force in member DC is

A.

100 t compressive

100 t compressive

B.

100 t tensile

100 t tensile

C.

zero

zero

D.

indeterminate

indeterminate

**Answer Option C**

5. If M, I, R, E, F, and Y are the bending moment, moment of inertia, radius of curvature, modulus of elasticity stress and the depth of the neutral axis at section, then

A.

B.

C.

D.

**Answer Option C**

6. The eccentricity (e) of a hollow circular column, external diameter 25 cm, internal diameter 15 cm for an eccentric load 100 t for non-development of tension, is

A. 2.75 cm

B. 3.00 cm

C. 3.50 cm

D. 4.25 cm

E. 5.0 cm

**Answer Option D**

7. If Ix and Iy are the moments of inertia of a section about X and Y axes, the polar moment of inertia of the section, is

A.

B.

C. IX + IY

D.

**Answer Option C**

8. Maximum shear stress theory for the failure of a material at the elastic limit, is known

A. Guest's or Trecas' theory

B. St. Venant's theory

C. Rankine's theory

D. Haig's theory

E. Von Mises's theory.

**Answer Option A**

9. The force in AC of the truss shown in the given figure, is

A. 5t tension

B. 4t tension

C. 4t compression

D. 5t compression

E. None of these.

**Answer Option B**

10. For determining the force in the member AB of the truss shown in the given figure by method of sections, the section is made to pass through AB, AD and ED and the moments are taken about

A. joint C

B. joint B

C. joint D

D. joint A

**Answer Option C**

11. A composite beam is composed of two equal strips one of brass and other of steel. If the temperature is raised

A. steel experiences tensile force

B. brass experiences compressive force

C. composite beam gets subjected to a couple

D. composite beam bends

E. All the above.

**Answer Option E**

12. A two hinged parabolic arch of span l and rise h carries a load varying from zero at the left end to ω per unit run at the right end. The horizontal thrust is

A.

B.

C.

D.

**Answer Option D**

13. The force in EC of the truss shown in the given figure, is

A. zero

B. 5t tension

C. 5t compression

D. 4t tension

E. None of these.

**Answer Option C**

14. Shear centre of a half circular section of radius r and of constant thickness, lies at a distance of x from the centre where x is

A.

B.

C.

D.

**Answer Option D**

15. Pick up the correct statement from the following:

A. The moment of inertia is calculated about the axis about which bending takes place

B. If tensile stress is less than axial stress, the section experiences compressive stress

C. If tensile stress is equal to axial stress, the section experiences compressive stress

D. If tensile stress is more than axial stress, some portion of the section experiences a tensile stress

E. All the above.

**Answer Option E**

16. The forces acting on the bar as shown in the given figure introduce

A. compressive stress

B. tensile stress

C. shear stress

D. none of these.

**Answer Option C**

17. The equation of a parabolic arch of span l and rise h, is given by

A.

B.

C.

D.

**Answer Option D**

18. Pick up the correct statement from the following:

A. A wire wound in spiral form, is called a helical spring

B. The pitch of a close coil spring, is very small

C. The angle made by the coil with horizontal, is called the angle of helix

D. In the open coil helical spring, the angle of helix is comparatively large

E. All the above.

**Answer Option E**

19. The horizontal thrust on the ends of a two hinged semicircular arch of radius R carrying

A. a uniformly distributed load ω per unit run over its right half span, is

B. a uniformly distributed load ω per unit run over its entire span is

C. a distributed load varying from zero at the left end to ω per unit horizontal run at the right end, is

D. all the above.

**Answer Option D**

20. Maximum principal stress theory for the failure of a material at elastic point, is known

A. Guest's or Trecas' theory

B. St. Venant's theory

C. Rankine's theory

D. Haig's theory

E. Von Mises's theory.

**Answer Option C**

21. The equivalent length is of a column of length L having both the ends fixed, is

A. 2L

B. L

C.

D.

**Answer Option C**

22. The moment of inertia of a rectangular section of width B and depth D about an axis passing through C.G. and parallel to its width is

A.

B.

C.

D.

E.

**Answer Option C**

23. A masonry dam (density = 20, 000 N/m3) 6 m high, one metre wide at the top and 4 m wide at the base, has vertical water face. The minimum stress at the base of the dam when the reservoir is full, will be

A. 75 N/m2

B. 750 N/m2

C. 7500 N/m2

D. 75000 N/m2

**Answer Option C**

24. The ratio of tangential and normal components of a stress on an inclined plane through θ° to the direction of the force, is :

A. sin θ

B. cos θ

C. tan θ

D. cos θ

E. sec θ

**Answer Option C**

25. For calculating the allowable stress of long columns is the empirical formula, known as

A. Straight line formula

B. Parabolic formula

C. Perry's formula

D. Rankine's formula.

**Answer Option B**

26. A steel plate d x b is sandwiched rigidly between two timber joists each D x B/2 in section. The moment of resistance of the beam for the same maximum permissible stress σ in timber and steel will be (where Young's modulus of steel is m times that of the timber).

A.

B.

C.

D.

**Answer Option B**

27. The ratio of crippling loads of a column having both the ends fixed to the column having both the ends hinged, is

A. 1

B. 2

C. 3

D. 4

**Answer Option D**

28. Maximum strain theory for the failure of a material at the elastic limit, is known as

A. Guest's or Trecas' theory

B. St. Venant's theory

C. Rankine's theory

D. Haig's theory

E. Von Mises's theory.

**Answer Option B**

29. A cantilever of length L is subjected to a bending moment M at its free end. If EI is the flexural rigidity of the section, the deflection of the free end, is

A.

B.

C.

D.

**Answer Option D**

30. The maximum bending moment for a simply supported beam with a uniformly distributed load w/unit length, is

A.

B.

C.

D.

**Answer Option C**

31. Pick up the correct statement from the following:

A. The structural member subjected to compression and whose dimensions are small as compared to its length, is called a stmt

B. The vertical compression members, are generally known as columns or stanchions

C. Deflection in lateral direction of a long column, is generally known as buckling

D. All the above.

**Answer Option D**

32. A short column (30 cm x 20 cm) carries a load P1 at 4 cm on one side and another load P2 at 8 cm on the other side along a principal section parallel to longer dimension. If the extreme intensity on either side is same, the ratio of P1 to P2 will be

A.

B.

C.

D.

**Answer Option C**

33. Gradually applied static loads do not change with time their

A. magnitude

B. direction

C. point of application

D. all the above.

**Answer Option D**

34. Slenderness ratio of a long column, is

A. area of cross-section divided by radius of gyration

B. area of cross-section divided by least radius of gyration

C. radius of gyration divided by area of cross-section

D. length of column divided by least radius of gyration.

**Answer Option D**

35. is the equation of Euler's crippling load if

A. both at the ends are fixed

B. both the ends are hinged

C. one end is fixed and other end is free

D. one end is fixed and other end is hinged.

**Answer Option A**

36. In the cable shown in the given figure, the minimum tension occurs at

A. A

B. B

C. C

D. between A and C

E. between B and C

**Answer Option C**

37. A shaft rotating N.R.M. under a torque T, transmits a power

A. Newton metres/sec

B. Newton metres/min

C. Newton metres/min

D. Newton metres/sec

**Answer Option A**

38. In the truss shown in given figure, the force in member BD is

A. 100 t compressive

B. 100 t tensile

C. zero

D. indeterminate

**Answer Option A**

39. The normal and tangential components of stress on an inclined plane through θ° to the direction of the force, will be equal if θ is

A. 45°

B. 30°

C. 60°

D. 90°

**Answer Option A**

40. If D and d are external and internal diameters of a circular shaft respectively, its polar moment of inertia, is

A.

B.

C.

D.

**Answer Option D**

41. A steel bar 20 mm in diameter simply-supported at its ends over a total span of 40 cm carries a load at its centre. If the maximum stress induced in the bar is limited to N/mm2, the bending strain energy stored in the bar, is

A. 411 N mm

B. 511 N mm

C. 611 Nmm

D. 711 N mm

**Answer Option C**

42. The deflection curve for the portal frame shown in the given figure is

A.

B.

C.

D.

**Answer Option D**

43. A close coil helical spring when subjected to a moment M having its axis along the axis of the helix

A. it is subjected to pure bending

B. its mean diameter will decrease

C. its number of coils will increase

D. all the above.

**Answer Option A**

44. For beams breadth is constant,

A. depth d ∝ M

B. depth d ∝ M

C. depth d ∝ 3 M

D. depth d ∝

**Answer Option B**

45. A body is said to be in equilibrium if

A. it moves horizontally

B. it moves vertically

C. it rotates about its C.G.

D. none of these.

**Answer Option D**

46. Keeping breadth constant, depth of a cantilever of length l of uniform strength loaded with uniformly distributed load w varies from zero at the free end and

A. at the fixed end

B.

C.

D. at the fixed end

**Answer Option B**

47. The force in CD of the truss shown in given figure, is

A. 3t compression

B. 3t tension

C. zero

D. 1.5t compression

E. 1.5t tension

**Answer Option C**

48. The deflection of a uniform circular bar of diameter d and length l, which extends by an amount e under a tensile pull W, when it carries the same load at its mid-span, is

A.

B.

C.

D.

**Answer Option C**

49. The ratio of the stresses produced by a suddenly applied load and by a gradually applied load on a bar, is

A.

B.

C. 1

D. 2

E. 3

**Answer Option D**

50. The forces acting normally on the cross section of a bar shown in the given figure introduce

A. compressive stress

B. tensile stress

C. shear stress

D. none of these.

**Answer Option A**

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