Objective of r.c.c code 456-2000

I. Select correct option/options from the following questions. (1 to 196)

1. Minimum grade of concrete for moderate exposure with normal weight aggregates is

(a) M 15

(b) M 20

(c) M 25

(d) M 35

 Ans-c

2. Concrete surfaces exposed to sea water spray is considered exposure condition

(a) extreme

(b) very severe

(c) severe

(d) moderate

Ans-B

3. Concrete surface buried under non-aggressive soil/groundwater is considered exposed to condition

(a) moderate

(b) severe

(c) very severe

(d) extreme

Ans-a

4. M 45 concrete is regarded as

(a) ordinary concrete

(b) standard concrete

(c) high strength concrete

(d) ultra-high strength concrete

Ans-v

5. M 75 concrete is regarded as

(a) ordinary concrete

(b) standard concrete

(c) high strength concrete

(d) ultra-high strength concrete

Ans-c

6. strength calculations and serviceability calculations, Poisson’s ratio of concrete is taken

respectively as

(a) 0.15 and 0.1

(b) 0.1 and 0.15

(c) 0.2 and 0.15

(d) 0.15 and 0.2

 Ans-d

7. In the absence of data the approximate value of the total shrinkage strain may be taken as

(a) 0.0001

(b) 0.0003

(c) 0.001

(d) 0.003

Ans-b

8. If age of loading on concrete structure is 28 days, the creep coefficient may be taken as

(a) 2.2

(b) 2.0

(c) 1.8

(d) 1.6

Ans-d

9. Yield strength of mild steel is

(a) 250 N/mm2

(b) 415 N/mm2

(c) 500 N/mm2

(c) 480 N/mm2

Ans-a

10. The Young’s modulus for all grades of steel is

(a) 180 kN/mm2

(b) 200 kN/mm2

(c) 210 kN/mm2

(d) 200 kN/cm2

Ans-b

11. Which one of the following is not the diameter of market form of reinforcing bar?

(a) 16 mm

(b) 18 mm

(c) 20 mm

(d) 22 mm

Ans-b

12. Bars larger than ______ diameter should not be bundled.

(a) 22 mm

(b) 25 mm

(c) 28 mm

(d) 32 mm

Ans-d

13. Which one of the following is not the diameter of the market form of reinforcing bars?

(a) 28 mm

(b) 30 mm

(c) 32 mm

(d) 36 mm

Ans-b

14. If a roof is sloping at 12°, imposed load to be considered in the design is

(a) 1.5 kN/m2

(b) 1.0 kN/m2

(c) 0.75 kN/m2

(d) 0.71 kN/m2

Ans-d

15. In design of a flat R.C.C. roof without access except for maintenance, imposed load to be

considered is

(a) 1.5 kN/m2

(b) 1.25 kN/m2

(c) 1.0 kN/m2

(d) 0.75 kN/m2

Ans-d

16. In the design of a seven-storey building, while designing the columns of 5th storey reduction in

imposed loads on floor is

(a) 0%

(b) 10%

(c) 20%

(d) 30%

Ans-c

17. In designing a structure at a height 25 m in a region with wind velocity V, the wind pressure to be

considered in

(a) 0.45 V2

(b) 0.5 V2

(c) 0.6 V2

(d) 0.75 V2

Ans-c

18. Upto a height of ______ wind pressure on a structure is considered to be uniform.

(a) 20 m

(b) 30 m

(c) 40 m

(d) 50 m

Ans-b

19. Snow load need not be considered in the design of structures in cold regions, if slope of the roof

is more than

(a) 25°

(b) 30°

(c) 45°

(d) 60°

Ans-d

20. Which one of the following is not correct load combination in structural design

(a) DL + WL

(b) DL + WL + IL

(c) DL + WL + SL

(d) DL + WL + IL + SL

Ans-d

where DL = dead load

WL = wind load

IL = imposed load

SL = wind load

21. A structure design should

(a) sustain all loads

(b) sustain the deformation

(c) should have adequate resistance to misuse and fire

(d) all the above

Ans-d

22. In the working stress method of R.C.C. design which one of the following is correct?

(a) Shear deformations are neglected.

(b) Stress-strain relation is linear, both for steel and concrete.

(c) The modular ratio between steel and concrete remains constant.

(d) All the above.

Ans-d

23. In the working stress method of R.C.C. design factor of safety used for concrete and steel are

respectively

(a) 3 and 1.85

(b) 4 and 1.85

(c) 4 and 2

(d) 3 and 1.5

Ans- a

26. The failure criteria in the ultimate load method of design is

(a) stress

(b) strain

(c) load

(d) all the above

Ans- b

27. Limit state method of R.C.C. design takes care of structure

A. Its safety

B. Its fitness throughout its designed life. Select your answer code from the list given below:

(a) Both A and B are true

(b) A is true but is not true

(c) A is not true but B is true

(d) Both A and B are not true.

Ans-a

28. Limit state method is based on probable

A. Load

B. Strength.

Select your answer code from the list given below:

(a) Both A and B are true

(b) A is true and B is false

(c) A is false and B is true

(d) Both A and B are false

Ans- a

29. Characteristic load means

(a) maximum load

(b) mean load

(c) mean load + 5 % of standard deviation

(d) mean load + 10 % of standard deviation

Ans- c

30. Characteristic strength is

(a) minimum assured strength

(b) minimum assured strength +1.64 times standard deviation

(c) mean strength

(d) mean strength + 1.64 times standard deviation

Ans-b

31. If standard deviation is 4 N/mm2

, the mean strength of M : 20 concrete should be

(a) 16 N/mm2

(b) 20 N/mm2

(c) 24 N/mm2

(d) 26.4 N/mm2

Ans- D

32. Partial safety factors for dead load and imposed load combination for limit state of serviceability

are

(a) 1.0 and 1.0

(b) 1.5 and 1.5

(c) 1.2 and 1.2

(d) 1.0 and 0.8

Ans- a

33. Partial safety factor for dead load, imposed load and wind load for limit state of collapse are

respectively

(a) 1.5, 1.5, 1.0

(b) 1.5, 1.2, 1.0

(c) 1.2, 1.2, 1.5

(d) 1.2, 1.2, 1.2

Ans- D

34. Partial safety factor for steel for limit state of collapse is

(a) 1.0

(b) 1.15

(c) 1.2

(d) 1.5

Ans-b

35. Partial safety factor for steel for limit state of deflection is

(a) 1.0

(b) 1.15

(c) 1.2

(d) 1.5

Ans- A

36. The stress strain curve for concrete is considered parabolic by I.S. code upto a strain of

(a) 0.0015

(b) 0.0020

(c) 0.0030

(d) 0.0035

Ans- b

37. IS code considers concrete has reached its limit state of collapse when the strain is

(a) 0.0015

(b) 0.0020

(c) 0.0030

(d) 0.0035

Ans- D

38. Which one of the following is the correct shape of stress block showing distribution of

compressive stress in concrete beam at limit state across the depth (Ref Fig. Q. 38).

Ans- d

39. The centroid of a compression block representing stress in concrete at limit state, the distance

being measured from extreme compression edge is

(a) 0.36 xu

(b) 0.42 xu

(c) 0.48 xu

(d) 0.53 xu

Àns- b

where xu = depth of compression cone.

40. Limiting value of depth of neutral axis in R.C. beam of depth d with Fe 415 steel is

(a) 0.36 d

(b) 0.42 d

(c) 0.48 d

(d) 0.53 d

Ans-d

42. Limiting moment carrying capacity

A. If Fe 415 steel is used is 0.138 fck bl

2

,

B. If Fe 500 steel is used is 0.148 fck bl

2

.

Select your answer code from the following.

(a) Both A and B are true

(b) A is true but B is false

(c) A is false but B is true

(d) Both A and B are false

Ans-b

45. One can go for doubly reinforced section

(a) to restrict depth of beam from architectural consideration

(b) to improve ductility of beam

(c) to reduce long-term deflections

(d) all the above

Ans-d

47. At section A in a beam 100 × is 3.0 and in another section B this value is 3.5. The design shear

strength of concrete tc

(a) at section A > at section B

(b) at section A = at section B

(c) at section A < at section B

(d) nothing can be said without knowing the loading pattern

Ans-b

48. In beam A 100 is same as in beam B. If beam A is of M 40 concrete and beam B of M 50

concrete, design shear strength tc

(a) of beam A > that of beam B

(b) of beam A is same as that of beam B

(c) of beam A < that of beam B

(d) nothing can be said definitely

Ans-b

49. In a R.C. beam shear reinforcement should be always in the form

(a) vertical stirrups

(b) inclined stirrups

(c) bent up bars with stirrups

(d) any one of the above

Ans-D