Civil Engineering - RCC Structures Design MCQs Part 4

1. After prestressing process is completed, a loss of stress is due to

A.
shrinkage of concrete

B.
elastic shortening of concrete

C.
creep of concrete

D.
creep of steel

E.
all the above.

 Answer Option E

2. The minimum head room over a stair must be

A.
200 cm

B.
205 cm

C.
210 cm

D.
200 cm

E.
230 cm

 Answer Option C

3. 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

A.
a key

B.
a cut-off wall

C.
a rib

D.
all the above.

 Answer Option D

4. The diameter of the column head support a flat slab, is generally kept

A.
0.25 times the span length

B.
0.25 times the diameter of the column

C.
4.0 cm larger than the diameter of the column

D.
5.0 cm larger than the diameter of the column

E.
none of these.

 Answer Option A

5. The steel generally used in R.C.C. work, is

A.
stainless

B.
mildsteel

C.
high carbon steel

D.
high tension steel.

 Answer Option B

6. Pick up the correct statement from the following:

A. Lateral reinforcement in R.C.C. columns is provided to prevent the longitudinal reinforcement from buckling

B. Lateral reinforcement prevents the shearing of concrete on diagonal plane

C. Lateral reinforcement stops breaking away of concrete cover, due to buckling

D. Lateral reinforcement in R.C.C. columns, is kept not less than 5 mm diameter

E. All the above.

 Answer Option E

7. The allowable tensile stress in mild steel stirrups, reinforced cement concrete, is

A. 1400 kg/cm2

B. 190 kg/cm2

C. 260 kg/cm2

D. 230 kg/cm2

 Answer Option A

8. If longitudinally spanning stairs are casted along with their landings, the maximum bending moment per metre width, is taken as

A.

B.

C.

D.

E.

 Answer Option B

9. If A is the sectional area of a prestressed rectangular beam provided with a tendon prestressed by a force P through its centroidal longitudinal axis, the compressive stress in concrete, is

A.

B.

C.

D.

E.

 Answer Option A

10. According to I.S.: 456, 1978 the thickness of reinforced concrete footing on piles at its edges, is kept less than

A. 5 cm

B. 10 cm

C. 15 cm

D. 20 cm

E. 25 cm

 Answer Option C

11. The self-weight of the footing, is

A. not considered for calculating the upward pressure on footing

B. also considered for calculating the upward pressure on footihg

C. not considered for calculating the area of the footing

D. both (b) and (c)

 Answer Option A

12. For normal cases, stiffness of a simply supported beam is satisfied if the ratio of its span to its overall depth does not exceed

A. 10

B. 15

C. 20

D. 25

E. 30

 Answer Option C

13. If the length of an intermediate span of a continuous slab is 5m, the length of the end span is kept

A. 4.5 m

B. 4.0 m

C. 3.5 m

D. 3.0 m

E. none of these.

 Answer Option A

14. If Md and Mt are the maximum bending moments due to dead load and live load respectively and F is the total effective pressure, for a balanced design of a prestreseed concrete beam of steel, is

A.

B.

C.

D.

 Answer Option B

15. The floor slab of a building is supported on reinforced cement floor beams. The ratio of the end and intermediate spans is kept

A. 0.7

B. 0.8

C. 0.9

D. 0.6

E. none of these.

 Answer Option C

16. If p1 and P2 are effective lateral loadings at the bottom and top exerted by a level earth subjected to a superload on the vertical face of height h of a retaining wall, the horizontal pressure p per unit length of the wall, is

A.

B.

C.

D.

 Answer Option C

17. Lapped splices in tensile reinforcement are generally not used for bars of size larger than

A. 18 mm diameter

B. 24 mm diameter

C. 30 mm diameter

D. 36 mm diameter

E. 32 mm diameter

 Answer Option D

18. 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

A. is safe in shear

B. is safe with stirrups

C. is safe with stirrups and inclined bars

D. needs revision of section

 Answer Option D

19. In a slab, the pitch of the main reinforcement should not exceed its effective depth

A. three times

B. four times

C. five times

D. two times.

 Answer Option A

20. The modular ratio m of a concrete whose permissible compressive stress is C, may be obtained from the equation.

A.

B.

C.

D.

E.

 Answer Option C

21. In a prestressed member it is advisable to use

A. low strength concrete only

B. high strength concrete only

C. low strength concrete but high tensile steel

D. high strength concrete and high tensile steel

E. high strength concrete but low tensile steel

 Answer Option D

22. The ratio of the breadth to effective depth of a beam is kept

A. 0.25

B. 0.50

C. 0.70

D. 0.75

E. none of these.

 Answer Option B

23. Spacing of stirrups in a rectangular beam, is

A. kept constant throughout the length

B. decreased towards the centre of the beam

C. increased at the ends

D. increased at the centre of the beam.

 Answer Option D

24. If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is

A. square

B. rectangular

C. trapezoidal

D. triangular.

 Answer Option B

25. If permissible compressive stress in concrete is 50 kg/cm2, tensile stress in steel is 1400 kg/cm2 and modular ratio is 18, the depth d of the beam, is

A.

B.

C.

D.

E.

 Answer Option A

26. For a continuous floor slab supported on beams, the ratio of end span length and intermediate span length, is

A. 0.6

B. 0.7

C. 0.8

D. 0.9

 Answer Option D

27. Steel bars are generally connected together to get greater length than the standard length by providing

A. strainght bar splice

B. hooked splice

C. dowel splice

D. all the above

 Answer Option D

28. Long and short spans of a two way slab are ly and lx and load on the slab acting on strips parallel to lx and ly be wx and wy respectively. According to Rankine Grashoff theory

A.

B.

C.

D.

E. none of these.

 Answer Option D

29. If p is the net upward pressure on a square footing of side b for a square column of side a, the maximum bending moment is given by

A.

B.

C.

D.

 Answer Option C

30. By over-reinforcing a beam, the moment of resistance can be increased not more than

A. 10%

B. 15%

C. 20%

D. 25%

 Answer Option D

31. The minimum thickness of a flat slab is taken

A. 13 cm

B. L/32 for end panels without drops

C. L/36 for end panels without drops

D. L/36 for interior panels without drop

E. all the above.

 Answer Option E

32. 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

A. half of the width of the slab

B. two-third of the width of the slab

C. three-fourth of the width of the slab

D. four-fifth of the width of the slab

E. three-fifth of the width of the slab.

 Answer Option C

33. Minimum spacing between horizontal parallel reinforcement of the same size should not be less than

A. one diameter

B. 2.5 diameters

C. 3 diameters

D. 3.5 diameters

E. 4 diameters

 Answer Option A

34. Columns may be made of plain concrete if their unsupported lengths do not exceed their least lateral dimension

A. two times

B. three times

C. four times

D. five times

E. six times.

 Answer Option C

35. An R.C.C. column is treated as short column if its slenderness ratio is less than

A. 30

B. 35

C. 40

D. 50

E. 60

 Answer Option D

36. If the tendon is placed at an eccentricity e below the centroidal axis of the lon-gitudial axis of a rectangular beam (sectional modulus Z and stressed load P in tendon) the stress at the extreme top edge

A. is increased by

B. is increased by

C. is decreased by

D. remains unchanged.

 Answer Option C

37. The maximum ratio of span to depth of a slab simply supported and spanning in one direction, is

A. 35

B. 25

C. 30

D. 20

E. 15

 Answer Option C

38. If Ac, Asc and A are areas of concrete, longitudinal steel and section of a R.C.C. column and m and σc are the modular ratio and maximum stress in the configuration of concrete, the strength of column is

A. σcAc + m σcAsc

B. σc(A - Asc) + m σcAsc

C. σc[A + (m - 1)ASC]

D. all the above.

 Answer Option D

39. The load stress of a section can be reduced by

A. decreasing the lever arm

B. increasing the total perimeter of bars

C. replacing larger bars by greater number of small bars

D. replacing smaller bars by greater number of greater bars

E. none of these.

 Answer Option C

40. If W is the load on a circular slab of radius R, the maximum radial moment at the centre of the slab, is

A.

B.

C.

D.

 Answer Option C

41. For M 150 grade concrete (1:2:4) the moment of resistance factor is

A. 0.87

B. 8.50

C. 7.50

D. 5.80

E. none of these.

 Answer Option B

42. For a ribbed slab

A. clear spacing between ribs shall not be greater than 4.5 cm

B. width of the rib shall not be less than 7.5 cm

C. overall depth of the slab shall not exceed four times the breadth of the rib

D. all the above.

 Answer Option D

43. A pile weighing W1 kg penetrates S metres with its last blow. If W2 is the weight of the hammer having a drop of H metres, the pile can carry a maximum external load

A.

B.

C.

D.

 Answer Option B

44. The maximum ratio of span to depth of a slab simply supported and spanning in two directions, is

A. 25

B. 30

C. 35

D. 40

E. 15

 Answer Option C

45. The neutral axis of a T-beam exists

A. within the flange

B. at the bottom edge of the slab

C. below the slab

D. all the above.

 Answer Option D

46. A pre-stressed concrete member is preferred because

A. its dimensions are not decided from the diagonal tensile stress

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

C. removal of cracks in the members due to shrinkage

D. all the above.

 Answer Option D

47. If W is the uniformly distributed load on a circular slab of radius R fixed at its ends, the maximum positive radial moment at its centre, is

A.

B.

C.

D. zero

E. none of these.

 Answer Option C

48. If p1 and p2 are mutually perpendicular principal stresses acting on a soil mass, the normal stress on any plane inclined at angle θ° to the principal plane carrying the principal stress p1, is :

A.

B.

C.

D.

E.

 Answer Option C

49. A very comfortable type of stairs is

A. straight

B. dog legged

C. geometrical

D. open newel.

 Answer Option D

50. If the neutral axis of a T-beam is below the slab, the relationship between the flange width B, depth of neutral axis n, thickness of the slab ds, effective depth of the beam d, gross area of tensile steel At and the modular ratio m may be stated as

A.

B.

C.

D. Bds(n - ds) = mAt(d - n)

 Answer Option C