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rcc structures design MCQs

Practise focused rcc structures design questions with marked answers for exam preparation and subject revision.

rcc structures design Mcqs
1. The maximum permissible size of aggregates to be used in casting the ribs of a slab, is______________?
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A. 10 mm

B. 7.5 mm

C. 5 mm

D. 15 mm

2. Columns may be made of plain concrete if their unsupported lengths do not exceed their least lateral dimension_______________?
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A. Two times

B. Three times

C. Four times

D. Five times

3. If R and T are rise and tread of a stair spanning horizontally, the steps are supported by a wall on one side and by a stringer beam on the other side, the steps are designed as beams of width_______________?
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A. R + T

B. 2 + T2)

C. T R

D. R T

4. A pre-stressed rectangular beam which carries two concentrated loads W at L/3 from either end, is provided with a bent tendon with tension P such that central one-third portion of the tendon remains parallel to the longitudinal axis, the maximum dip h is_____________________?
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A. WL/P

B. WL/2P

C. WL/4P

D. WL/3P
5. If C is creep coefficient, f is original pre-stress in concrete, m is modular ratio, E is Youngs modulus of steel and e is shrinkage strain, the combined effect of creep and shrinkage is________________?
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A. (1 C)mf + eE

B. (1 C) mf eE

C. (C 1)mf eE

D. (C 1)mf + eE
6. High strength concrete is used in pre-stressed member________________?
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A. To provide high bond stresses

B. All the above

C. To overcome high bearing stresses developed at the ends

D. To overcome bursting stresses at the ends

7. Top bars are extended to the projecting parts of the combined footing of two columns Ldistance apart for a distance of_______________?
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A. 0.1 L from the outer edge of column

B. One -fourth the distance of projection

C. 0.1 L from the centre edge of column

D. Half the distance of projection

8. The design of heel slab of a retaining wall is based on the maximum bending moment due to______________?
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A. Its own weight

B. Load of the surcharge, if any

C. Weight of the soil above it

D. All the above
9. Enlarged head of a supporting column of a flat slab is technically known as______________?
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A. Drop panel

B. Supporting end of the column

C. Capital

D. Top of the column

10. The transverse reinforcements provided at right angles to the main reinforcement_______________?
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A. All the above

B. Resist the temperature stresses

C. Distribute the load

D. Resist the shrinkage stress

11. If A is the area of the foundation of a retaining wall carrying a load W and retaining earth of weight w per unit volume, the minimum depth (h) of the foundation from the free surface of the earth, is )/(1 + sin )]_________________?
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A. h = (W/Aw) [(1 )/(1 + sin )]

B. h W/Aw) [(1 )/(1 + sin )]

C. h = (W/Aw) [(1 + )/(1 + sin )]

D. h = (W/Aw) [(1

12. If the tendon is placed at an rectangular beam (sectional top edge)________________?
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A. Is decreased by Pe/Z

B. Is increased by Pe/Z

C. Is increased by PZ/e

D. Remains unchanged

13. If the bearing capacity of soil is 10 tonnes/cm2 and the projection of plain concrete footing from walls, is a cm, the depth D of footing is_______________?
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A. D = 0.775 a

B. D = 0.775 a

C. D = 0.0775 a

D. D = 0.775 a2

14. The self-weight of the footing, is_____________?
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A. Not considered for calculating the upward pressure on footing

B. Also considered for calculating the upward pressure on footing

C. Not considered for calculating the area of the footing

D. Both B. and C

15. The neutral axis of a T-beam exists_________________?
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A. Below the slab

B. At the bottom edge of the slab

C. All the above

D. Within the flange

16. A pre-cast pile generally used, is______________?
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A. Square

B. Square with corners chamfered

C. Octagonal

D. Circular

17. Minimum spacing between horizontal parallel reinforcement of the same size should not be less than________________?
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A. One diameter

B. 3 diameters

C. 2.5 diameters

D. 3.5 diameters

18. The minimum thickness of the cover at the end of a reinforcing bar should not be less than twice the diameter of the bar subject to a minimum of___________________?
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A. 10 mm

B. 15 mm

C. 20 mm

D. 25 mm
19. Lapped splices in tensile reinforcement are generally not used for bars of size larger than______________?
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A. 18 mm diameter

B. 24 mm diameter

C. 36 mm diameter

D. 30 mm diameter

20. mutually perpendicular principal stresses acting on a soil mass, the normal stress If p1 and p2 are________________?
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A. 2

B. [(p p p p cos 2

C. [(p p p p cos 2

D. [(p p p p /2] sin 2

E. [(p p p p to the principal plane carrying the principal stress p1, is:

21. Design of a two way slab simply supported on edges and having no provision to prevent the corners from lifting, is made by_________________?
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A. Rankine formula

B. Rankine Grashoff formula

C. Marcus formula

D. Grashoff formula

22. In the zone of R.C.C. beam where shear stress is less than 5 kg/cm2, nominal reinforcement is provided at a pitch of________________?
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A. One and half lever arm of the section

B. One -half lever arm of the section

C. Lever arm of the section

D. One-third lever arm of the section

23. According to I.S. : 456, slabs which span in two directions with corners held down, are assumed to be divided in each direction into middle strips and edge strips such that the width of the middle strip, is______________?
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A. Half of the width of the slab

B. Three-fourth of the width of the slab

C. Two -third of the width of the slab

D. Four-fifth of the width of the slab

24. Steel bars are generally connected together to get greater length than the standard length by providing_______________?
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A. Hooked splice

B. Straight bar splice

C. All the above

D. Dowel splice

25. The minimum clear cover for R.C.C. columns shall be_________________?
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A. Greater of 25 mm or diameter

B. Smaller of 25 mm or diameter

C. Smaller of 40 mm or diameter

D. Greater of 40 mm or diameter

26. The maximum ratio of span to depth of a slab simply supported and spanning in one direction, is______________?
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A. 20

B. 30

C. 25

D. 35

27. If the ratio of the span to the overall depth does not exceed 10, the stiffness of the beam will ordinarily be satisfactory in case of a__________________?
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A. None of these

B. Simply supported beam

C. Cantilever beam

D. Continuous beam

28. The load stress of a section can be reduced by______________?
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A. Increasing the total perimeter of bars

B. Replacing larger bars by greater number of small bars

C. Decreasing the lever arm

D. Replacing smaller bars by greater number of greater bars

29. If is the net upward pressure on a square footing of side for a square column of side , the maximum bending moment is given by_________________?
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A. B.M = pb (b + a)/8

B. B.M = pb (b a)/4

C. B.M = pb (b a)/8

D. B.M = pb (c a)/4

30. To ensure uniform pressure distribution, the thickness of the foundation, is__________________?
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A. Decreased gradually towards the edge

B. Kept uniform throughout

C. Kept zero at the edge

D. Increased gradually towards the edge

31. Spacing of stirrups in a rectangular beam, is__________________?
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A. Decreased towards the centre of the beam

B. Increased at the ends

C. Increased at the centre of the beam

D. Kept constant throughout the length

32. The pitch of the main bars in a simply supported slab, should not exceed its effective depth by_____________?
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A. Six times

B. Five times

C. Four times

D. Three times

33. The minimum thickness of a flat slab is taken_________________?
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A. L/36 for end panels without drops

B. All the above

C. L/32 for end panels without drops

D. L/36 for interior panels without drop

34. If is the uniformly distributed load on a circular slab of radius maximum positive radial moment at its centre, is__________________?
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A. 2WR/16

B. 3WR/16

C. WR/16

D. None of these

35. An R.C.C. beam of 6 m span is 30 cm wide and has a lever arm of 55 cm. If it carries a U.D.L. of 12 t per m and allowable shear stress is 5 kg/cm2, the beam________________?
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A. Is safe in shear

B. Is safe with stirrups and inclined bars

C. Is safe with stirrups

D. Needs revision of section
36. In case the factor of safety against sliding is less than 1.5, a portion of slab is constructed downwards at the end of the heel slab, which is known as___________________?
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A. All the above

B. A key

C. A rib

D. A cut-off wall

37. After pre-stressing process is completed, a loss of stress is due to______________?
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A. Elastic shortening of concrete

B. Shrinkage of concrete

C. All the above

D. Creep of concrete

38. The floor slab of a building is supported on reinforced cement floor beams. The ratio of the end and intermediate spans is kept______________?
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A. 0.6

B. 0.9

C. 0.8

D. 0.7

39. If p1 and P2 are effective lateral loadings at the bottom and top exerted by a level earth subjected to a super-load on the vertical face of height h of a retaining wall, the horizontal pressure p per unit length of the wall, is____________________?
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A. ( h

B. [( + )/2] h

C. [( + )/4] h

D. [( )/2] h

40. If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is__________________?
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A. Rectangular

B. Trapezoidal

C. Square

D. Triangular

41. The modular ratio m of a concrete whose permissible compressive stress is C, may be obtained from the equation.
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A. m = 2800/3C

B. m = 3500/3C

C. m = 700/3C

D. m = 1400/3C

42. on a circular slab of radius , the maximum radial moment at the centre of the If is the load slab, is WR/16_____________?
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A. t; NON OF THESE

B. 5WR/16

C. 3WR/16

D. 2WR/16

43. longitudinal bars and lateral stirrups, is__________________?
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A. Stress in concrete area of concrete + Stress in steel area of steel

B. None of these

C. Stress in steel area of steel

D. Stress in concrete area of concrete

44. The spacing of transverse reinforcement of column is decided by the following consideration_______________?
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A. Sixteen times the diameter of the smallest longitudinal reinforcing rods in the column

B. Forty-eight times the diameter of transverse reinforcement

C. All the above

D. The least lateral dimension of the column

45. If is the sectional area of a pre-stressed rectangular beam provided with a tendon pre -stressed by a force through its centroidal longitudinal axis, the compressive stress in concrete, is_______________?
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A. A/P

B. P/2A

C. 2A/P

D. P/A
46. The width of the flange of a L-beam, should be less than______________?
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A. One- sixth of the effective span

B. Least of the above

C. Breadth of the rib + four times thickness of the slab

D. Breadth of the rib + half clear distance between ribs

47. Total pressure on the vertical face of a retaining wall of height h acts parallel to free surface and from the base at a distance of_____________________?
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A. h/2

B. h /4

C. h/3

D. 2h/3

48. 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__________________?
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A. Is safe with stirrups

B. Is safe with stirrups and inclined members

C. Needs revision of the section

D. Safe in shear
49. A pre-stressed concrete member is preferred because___________________?
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A. Removal of cracks in the members due to shrinkage

B. Its dimensions are not decided from the diagonal tensile stress

C. All the above

D. Large size of long beams carrying large shear force need not be adopted

50. As per IS : 456, the reinforcement in a column should not be less than________________?
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A. 0.5% and not more than 5% of cross-sectional area

B. 0.8% and not more than 8% of cross-sectional area

C. 0.6% and not more than 6% of cross-sectional area

D. 0.7% and not more than 7% of cross-sectional area