### Civil Engineering - Theory of Structures MCQs Part 1

1. The assumption in the theory of bending of beams, is :

A.
material is homogeneous
B.
material is isotropic
C.
Young's modulus is same in tension as well as in compression
D.
each layer is independent to expand or to contract
E.
all the above.

2. The shape factor of standard rolled beam section varies from

A.
1.10 to 1.20
B.
1.20 to 1.30
C.
1.30 to 1.40
D.
1.40 to 1.50

3. Shear strain energy theory for the failure of a material at elastic limit, is due to

A.
Rankine
B.
Guest or Trecas
C.
St. Venant
D.
Haig
E.
Von Mises.

4. The point of contraflexure is the point where

A.
B.M. changes sign
B.
B.M. is maximum
C.
B.M. is minimum
D.
S.F. is zero.

5. The normal component of a force inclined through θ° is obtained by multiplying the force by

A.
sin θ
B.
cos θ
C.
tan θ
D.
sin θ cos θ
E.
sin2θ

6. A material which obeys Hook's law, is subjected to direct stress σ0. At its elastic limit, the following statement is true,

A. Strain is equal to
B. Maximum shear stress =
C. Strain energy =
D. Shear strain energy =
E. All the above.

7. In the truss shown in the given figure, the force in member BC is

A. 100 t compressive
B. 100 t tensile
C. zero
D. indeterminate

8. A concentrated load P is supported by the free end of a quadrantal ring AB whose end B is fixed. The ratio of the vertical to horizontal deflections of the end A, is

A. π
B.
C.
D.

9. Stress may be defined as

A. force per unit length
B. force per unit volume
C. force per unit area
D. none of these.

10. Total strain energy theory for the failure of a material at 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.

11. Stress may be expressed in Newtons

A. per millimetre square (N/mm2)
B. per centimetre square (N/cm2)
C. per metre square (N/m2)
D. All of the above.

12. Principal planes are subjected to

A. normal stresses only
B. tangential stresses only
C. normal stresses as well as tangential stresses
D. none of these.

13. In plastic analysis, the shape factor for a circular section, is

A. 1.5
B. 1.6
C. 1.7
D. 1.75

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

A. at the fixed end
B. at the fixed end
C. at the fixed end
D. at the fixed end

15. The total strain energy of a beam of length L, having moment of inertia of its section I, when subjected to a bending moment M, is

A.
B.
C.
D.

16. A load of 1960 N is raised at the end of a steel wire. The minimum diameter of the wire so that stress in the wire does not exceed 100 N/mm2 is :

A. 4.0 mm
B. 4.5 mm
C. 5.0 mm
D. 5.5 mm
E. 6.0 mm

17. The force in BF of the truss shown in given figure, is

A. 4t tension
B. 4t compression
C. 4.5t tension
D. 4.5t compression
E. zero.

18. The radius of gyration of a section of area A and least moment of inertia I about the centroidal axis, is

A.
B.
C.
D.

19. A simply supported beam carries varying load from zero at one end and w at the other end. If the length of the beam is a, the maximum bending moment will be

A.
B.
C.
D.

20. In plastic analysis, the shape factor for rectangular section, is

A. 1.4
B. 1.5
C. 1.6
D. 1.7

21. In case of a simply supported rectangular beam of span L and loaded with a central load W, the length of elasto-plastic zone of the plastic hinge, is

A.
B.
C.
D.
E.

22. Pick up the correct statement from the following:

A. Hoop strain of the walls of a cylinder due to liquid is
B. Longitudinal strain in the walls of a cylinder due to liquid is
C. Volumetric change in the cylinderdue to liquid is
D. All the above.

23. A material may fail if

A. maximum principal stress exceeds the direct stress σ0
B. maximum strain exceeds
C. maximum shear stress exceeds
D. total strain energy exceeds
E. all the above.

24. A truss containing j joints and m members, will be a simple truss if

A. m = 2j - 3
B. j = 2m - 3
C. m = 3j - 2
D. j = 3m - 2

25. The stiffness of the close coil helical spring is

A.
B.
C.
D.

26. If E, N, K and 1/m are modulus of elasticity, modulus of rigidity. Bulk modulus and Poisson ratio of the material, the following relationship holds good

A.
B.
C.
D. all the above.

27. The ratio of maximum shear stress to average shear stress of a circular beam, is

A.
B.
C.
D.

28. A rolled steel joist is simply supported at its ends and carries a uniformly distributed load which causes a maximum deflection of 10 mm and slope at the ends of 0.002 radian. The length of the joist will be,

A. 10 m
B. 12 m
C. 14 m
D. 16 m
E. 18 m

29. A steel rod 1 metre long having square cross section is pulled under a tensile load of 8 tonnes. The extension in the rod was 1 mm only. If Esteel = 2 x 106 kg/cm2, the side of the rod, is

A. 1 cm
B. 1.5 cm
C. 2 cm
D. 2.5 cm

30. The maximum deflection due to a uniformly distributed load w/unit length over entire span of a cantilever of length l and of flexural rigidly EI, is

A.
B.
C.
D.

31. A material is said to be perfectly elastic if

A. it regains its original shape on removal of the load
B. It regains its original shape partially on removal of the load
C. it does not regain its original shape at all
D. none of these.

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

A. Straight line formula
B. Parabolic formula
C. Perry's formula
D. Rankine's formula.

33. Beams composed of more than one material, rigidly connected together so as to behave as one piece, are known as

A. Compound beams
B. Indeterminate beams
C. Determinate beams
D. Composite beams.

34. Pick up the correct statement from the following:

A. In a loaded beam, the moment at which the first yield occurs is called yield moment
B. In a loaded beam, the moment at which the entire section of the beam becomes fully plastic, is called plastic moment
C. In a fully plastic stage of the beam, the neutral axis divides the section in two sections of equal area
D. The ratio of plastic moment to the yield moment, is called shape factor
E. All the above.

35. The maximum magnitude of shear stress due to shear force F on a rectangular section of area A at the neutral axis, is

A.
B.
C.
D.

36. Two bars, one of steel and the other of copper having areas of cross-sections As and Ac, coefficient of expansion αs and αc and Young's Modulii Es and Es are rigidly connected together at the ends and subjected to temperature change of t°. If the length of the bars initially is L, the final extension δ of the two bars at t° temperature is given by

A.
B.
C.
D.

37. The tangential component of stress on an plane inclined θ° to the direction of the force, may be obtained by multiplying the normal stress by

A. sin θ
B. cos θ
C. tan θ
D. sin θ cos θ
E. sin2θ

38. The force in AD of the truss shown in given figure, is

A. 4.0t compression
B. 3.0t compression
C. 0.5t compression
D. 0.5t tension
E. zero.

39. There are two hinged semicircular arches A, B and C of radii 5 m, 7.5 m and 10 m respectively and each carries a concentrated load W at their crowns. The horizontal thrust at their supports will be in the ratio of

A. 1 : 1 1/2 : 2
B. 2 : 1 1/2 : 1
C. 1 : 1 : 2
D. none of these.

40. A spring of mean radius 40 mm contains 8 action coils of steel (N = 80000 N/mm2), 4 mm in diameter. The clearance between the coils being 1 mm when unloaded, the minimum compressive load to remove the clearance, is

A. 25 N
B. 30 N
C. 35 N
D. 40 N

41. A shaft is subjected to bending moment M and a torque T simultaneously. The ratio of the maximum bending stress to maximum shear stress developed in the shaft, is

A.
B.
C.
D.

42. The ratio of the deflections of the free end of a cantilever due to an isolated load at l/3rd and 2/3rd of the span, is

A.
B.
C.
D.

43. If Q is load factor, S is shape factor and F is factor of safety in elastic design, the following:

A. Q = S + F
B. Q = S - F
C. Q = F - S
D. Q = S x F
E.

44. In plastic analysis, the shape factor for a triangular section, is

A. 1.5
B. 1.34
C. 2.34
D. 2.5

45. Pick up the correct statement from the following:

A. The point of intersection of the bending axis with the cross section of the beam, is called shear centre
B. For I sections, the shear centre coincides with the centroid of the cross section of the beam
C. For channels, the shear centre does not concide its centroid
D. Bending loads should pass through the shear centre to avoid twisting
E. All the above.

46. Pick up the correct statement from the following:

A. The bending moment which when acting alone would produce the maximum stress equal to the major principal stress caused by combined bending and torsion, is called equivalent bending moment
B. Mcg = (M M2 + r2) where letters carry their usual meanings
C. Tcp = m2 + T2 where letters carry their usual meanings
D. The torque which when acting alone would produce maximum shear stress equal to the maximum shear stress caused by the combined bending and torsion, is called equivalent torque
E. All the above.

47. If ΣH and ΣV are the algebraic sums of the forces resolved horizontally and vertically respectively, and ΣM is the algebraic sum of the moments of forces about any point, for the equilibrium of the body acted upon

A. ΣH = 0
B. ΣV = 0
C. ΣM = 0
D. all the above.

48. For determining the support reactions at A and B of a three hinged arch, points B and C are joined and produced to intersect the load line at D and a line parallel to the load line through A at D'. Distances AD, DD' and AD' when measured were 4 cm, 3 cm and 5 cm respectively. The angle between the reactions at A and B is

A. 30°
B. 45°
C. 60°
D. 90°

49. Pick up the incorrect statement from the following : The torsional resistance of a shaft is directly proportional to

A. modulus of rigidity
B. angle of twist
C. reciprocal of the length of the shaft
D. moment of inertia of the shaft section.