### Civil Engineering - RCC Structures Design MCQs Part 3

1. If permissible working stresses in steel and concrete are respectively 1400 kg/cm2 and 80 kg/cm2 and modular ratio is 18, in a beam reinforced in tension side and of width 30 cm and having effective depth 46 cm, the lever arms of the section, is

A.
37 cm
B.
38 cm
C.
39 cm
D.
40 cm

2. 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)

A.
B.
C.
D.
E.

3. 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

A.
B.
C.
D.
E.

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

A.
fixed end
B.
free end
C.
mid span
D.
mid span and fixed support.

5. 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

A.
B.
C.
D.
E.

6. Piles are usually driven by

A. diesel operated hammer
B. drop hammer
C. single acting steam hammer
D. all the above.

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

A. 100 kg/cm2
B. 200 kg/cm2
C. 300 kg/cm2
D. 400 kg/cm2
E. 500 kg/cm2

8. The angle of internal friction of soil mass is the angle whose

A. tangent is equal to the rate of the maximum resistance to sliding on any internal inclined plane to the normal pressure acting on the plane
B. sine is equal to the ratio of the maximum resistance to sliding on any internal inclined plane to the normal pressure acting on the plane
C. cosine is equal to the ratio of the maximum resistance sliding on any internal inclined plane to the normal pressure acting on the plane
D. none of these.

9. The anchorage value of a hook is assumed sixteen times the diameter of the bar if the angle of the bend, is

A. 30°
B. 40°
C. 45°
D. 60°
E. all the above.

10. Top bars are extended to the projecting parts of the combined footing of two columns L distance apart for a distance of

A. 0.1 L from the outer edge of column
B. 0.1 L from the centre edge of column
C. half the distance of projection
D. one-fourth the distance of projection.

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

A. tension is resisted by tension steel
B. compression is resisted by compression steel
C. stress in tension steel equals the stress in compression steel
D. no stress is developed in compression concrete as well as in tension concrete
E. all the above.

12. The thickness of the flange of a Tee beam of a ribbed slab is assumed as

A. width of the rib
B. depth of the rib
C. thickness of the concrete topping 0d) half the thickness of the rib
D. twice the width of the rib.

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

A. under-reinforced section
B. over reinforced section
C. economic section
D. critical section.

14. 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

A. 12 bar diameters
B. 18 bar diameters
C. 24 bar diameters
D. 30 bar diameters
E. 36 bar diameters

15. If At is the gross area of steel in tension, d is the effective depth of the beam and y is the depth of the centre of gravity of the resultant compression, the moment of resistance M of the beam, is given by

A. M = At(d - y)
B. M = Atf(d - y)
C. M = Atf(d + y)
D. M =
E. none of these.

16. A pre-stressed concrete member

B. is made of reinforced concrete
C. is stressed after casting
D. possesses internal stresses.

17. A part of the slab may be considered as the flange of the T-beam if

A. flange has adequate reinforcement transverse to beam
B. it is built integrally with the beam
C. it is effectively bonded together with the beam
D. all the above.

18. An R.C.C. roof slab is designed as a two way slab if

A. it supports live loads in both directions
B. the ratio of spans in two directions is less than 2
C. the slab is continuous over two supports
D. the slab is discontinuous at edges.

19. If C is creep coefficient, f is original prestress in concrete, m is modular ratio, E is Young's modulus of steel and e is shrinkage strain, the combined effect of creep and shrinkage is:

A. (1 - C)mf - eE
B. (C - 1)mf + eE
C. (C - 1)mf - eE
D. (1 - C)mf + eE

20. In a combined footing for two columns carrying unequal loads, the maximum hogging bending moment occurs at

C. a point equidistant from either column
D. a point of the maximum shear force
E. a point of zero shear force.

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

A. 10%
B. 20%
C. 30%
D. 40%
E. 50%

22. The Total pressure on the vertical face of a retaining wall of height h exerted by the retained earth weighing w per unit volume having an angle of surcharge α°, is :

A.
B.
C.
D.

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

A. 0.3 H
B. 0.4 H
C. 0.5 H
D. 0.6 H
E. 0.7 H

24. 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

A. 51.5
B. 52.5
C. 53.5
D. 54.5
E. 55.5

25. If depth of slab is 10 cm, width of web 30 cm, depth of web 50 cm, centre to centre distance of beams 3 m, effective span of beams 6 m, the effective flange width of the beam, is

A. 200 cm
B. 300 cm
C. 150 cm
D. 100 cm

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

A. 6 legged
B. 8 legged
C. 10 legged
D. 12 legged
E. none of these.

27. A flat slab is supported

A. on beams
B. on columns
C. on beams and columns
D. on columns monolithicaily built with slab
E. all the above

28. A singly reinforced beam has breadth b, effective depth d, depth of neutral axis n and critical neutral axis n1. If fc and ft are permissible compressive and tensile stresses, the moment to resistance of the beam, is

A.
B.
C.
D. all the above

29. If diameter of a reinforcement bar is d, the anchorge value of the hook is

A. 4d
B. 8d
C. 12d
D. 16d
E. none of these.

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

A. one diameter of thinner bar
B. one diameter of thicker bar
C. sum of the diameters of ihinner and thicker bars
D. twice the diameter of thinner bar
E. none of these.

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

A. continued up
B. bent inward at the floor level
C. stopped just below the floor level and separate lap bars provided
D. all the above.

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

A. Freyssinet system
B. Magnel-Blaton system
C. C.C.L. standard system
D. Lee-McCall system.

33. The minimum clear cover for R.C.C. columns shall be

A. greater of 40 mm or diameter
B. smaller of 40 mm or diameter
C. greater of 25 mm or diameter
D. smaller of 25 mm or diameter

34. If jd is the lever arm and ΣO is the total perimeter of reinformcement of an R.C.C. beam, the bond stress at the section having Q shear force, is

A.
B.
C.
D.

35. If the loading on a prestressed rectangular beam, is uniformly distributed, the tendon to be provided should be .

A. straight below centroidal axis
B. parabolic with convexity downward
C. parabolic with convexity upward
D. straight above centroidal axis
E. none of these.

36. The live load to be considered for an accessible roof, is

A. Nil
B. 75 kg/m3
C. 150 kg/m2
D. 200 kg/cm2

37. A foundation is called shallow if its depth, is

A. one-fourth of its width
B. half of its width
C. three-fourth of its width
D. equal to its width
E. all the above.

38. A circular slab subjected to external loading, deflects to form a

A. semi-hemisphere
B. ellipsoid
C. parabolloid
D. none of these.

39. An R.C.C beam of 25 cm width has a clear span of 5 metres and carries a U.D.L. of 2000 kg/m inclusive of its self weight. If the lever arm of the section is 45 cm., the beam is

A. safe in shear
B. is safe with stirrups
C. is safe with stirrups and inclined members
D. needs revision of the section.

40. In a doubly-reinforced beam if c and t are stresses in concrete and tension reinforcement, d is the effective depth and n is depth of critical neutral axis n, the following relationship holds good

A.
B.
C.
D.
E.

41. 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

A. 10 mm
B. 15 mm
C. 20 mm
D. 25 mm
E. 30 mm

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

A. equal or less than 5 kg/cm2, no shear reinforcement is provided
B. greater than 4 kg/cm2, but less than 20 kg/cm2, shear reinforcement is provided
C. greater than 20 kg/cm2, the size of the section is changed
D. all the above.

43. If Sb, is the average bond stress on a bar of diameter d subjected to maximum stress t, the length of the embedment l is given by

A.
B.
C.
D.
E.

44. On piles, the drop must be at least

A. 80 cm
B. 100 cm
C. 120 cm
D. 140 cm
E. 150 cm

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

A.
B.
C.
D.
E.

46. An under-reinforced section means

A. Steel is provided at the under side only
B. Steel provided is insufficient
C. Steel provided on one face only
D. Steel will yield first.

47. The spacing of transverse reinforcement of column is decided by the following consideration.

A. The least lateral dimension of the column
B. Sixteen times the diameter of the smallest longitudinal reinforcing rods in the column
C. Forty-eight times the diameter of transverse reinforcement
D. All the above.

48. P is the prestressed force applied to the tendon of a rectangular prestressed beam whose area of cross section is A and sectional modulus is Z. The maximum stress f in the beam, subjected to a maximum bending moment M, is

A.
B.
C.
D.
E.

49. 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

A.
B.
C.
D.

50. The diameter of transverse reinforcement of columns should be equal to one-fourth of the diameter of the main steel rods but not less than

A. 4 mm
B. 5 mm
C. 6 mm
D. 7 mm
E. 8 mm