Important 1000 MCQ For CIVIL Junior Engineer : Part 4

Important 1000 MCQ For CIVIL Junior Engineer

30. Angle of inclination of the lacing bar
with the longitudinal axis of the
column should preferably be between
_______.
A. 10° to 30° B. 30° to 80°
C. 40° to 70° D. 20° to 70°

Correct Ans. C

Solution:

  • lacing bar shall be inclined at 400 to 700 to axis of built up member or longitudinal axis of the member.

31. If a rolled steel flat designated as 55
I.S.F. 12 mm is used as lacing, then
minimum radius of gyration will be
______.

A. 3 mm B. 6 mm
C. 3.46 mm D. 3.8 mm

Correct Ans. C

Solution:

  • radius of gyration, r = √1/12(55×123)/(55×12) r= √12 = 3.46 mm.

32. If ‘b’ is the width of the plate and ‘d’
is the diameter of the rivet, then the
efficiency of a riveted joint having
diamond riveting is given by ______.

A. (b-d)/b B. (b-d)/d
C. (b -2d)/b D. (b-2d)/d

Correct Ans. A

Solution:

  • Efficiency of a joint = (strength of joint)/(strength of solid plate) So, ղ = An/Ag (other values are constant in this case) ղ = (b-d).t/(b.t) = (b-d)/b

where t is the thickness of the plate

Important 1000 MCQ For CIVIL Junior Engineer : Part 3

33. If the loading on a simply supported
prestressed concrete beam is
uniformly distributed, the centroid of
tendons should be preferably ______.

A. A straight profile along the
centroidal axis
B. A straight profile along with the
lower kern
C. A parabolic profile with convexity
downward
D. A circular profile with convexity
upward

Correct Ans. C

Solution:

  • As shown in figure. The centroid of tendon in case of pre-stressed concrete Look like as a parabolic profile with convexity downward.

34. According to Whitney’s theory, the
maximum depth of concrete stress
block in a balanced RCC beam section
of depth ‘d’ is ______.

A. 0.3 d B. 0.43 d
C. 0.5 d D. 0.53 d

Correct Ans. D

Solution:

  • For balanced R.C.C beam If we use mild steel then for fy=250

Xu,max/d = .53
Xu,max = .53d

35. The main reinforcement of a RC slab
consists of 10 mm bars at 10 cm
spacing. If it is desired to replace 10
mm bars by 12 mm bars, then the
spacing of 12 mm bars should be
______.

A. 12cm B. 14cm
C. 14.40 cm D. 16 cm

Correct Ans. C
Solution:

  • Spacing of reinforcement is directly proportional to the area of reinforcement.

So, s1/s2 = d12/d22
10/s2 = 102/122
So, s2 = 14.4 cm.

36. The final deflection due to all loads
including the effects of temperature,
creep and shrinkage and measured
from as cast level of supports of
floors, roofs and all other horizontal
members should not exceed _____.

A. Span/350 B. Span/300
C. Span/250 D. Span/200

Correct Ans. C
Solution:

  • maximum deflection in a beam should not exceed, length of the span/250

So, for 5m span deflection should not
exeed 20mm.

37. A reinforced cantilever beam of span
4 m has a cross section of 150×500
mm. If checked for lateral stability
and deflection, the beam will ______.

A. Fail in deflection only
B. Fail in lateral stability only
C. Fail in both deflection and lateral
stability
D. Satisfy the requirements of
deflection and lateral stability

Correct Ans. C
Solution:

  • Lateral stability- For cantilever beam, span≤25b (it should be satisfied) 4m≤25×0.150m =3.75 4>3.75 so, it will fail. For the control of vertical deflection- For cantilever beam (l/d)basic ≤ 7 Here, (l/d)provided = 4000/500 = 8 should be less than (l/d)max. So, it will also fail.(not satisfying the condition)

38. Shear span is defined as the zone
where ______.
A. Bending moment is zero
B. Shear force is zero
C. Shear force is constant
D. Bending moment is constant

Correct Ans. C

Solution.

  • Shear span is the distance from the point of application of concentrated force to its respective Reaction force (supporting column). Throughout single Shear Span the Shear Force is constant, i.e. have same value of Shear Force throughout a single Shear Span. “Distance over which the shear is constant”

39. Limit state of serviceability of
prestressed concrete sections should
satisfy ______.

A. Cracking, deflection and
maximum compression
B. Cracking only
C. Deflection and cracking
D. Deflection and maximum
compression

Correct Ans. C
Solution:

limit state of serviceability-

  • 1) Cracking or flexure check.(which
  • depends on % of reinforcement)
  • 2) Deflection check.( (l/d)provided
  • should be less than (l/d)max)
  • 3) limit state of vibration

Important 1000 MCQ For CIVIL Junior Engineer : Part 1

40. The side face reinforcement, if
required in a T beam will be ______.

A. 0.1 % of the web area
B. 0.15 % of the web area
C. 0.02 % to 0.3 % of the web area
depending upon the breadth of the
web
D. Half of the longitudinal
reinforcement

Correct Ans. A

Solution:

  • Side face reinforcement in the web of the beam is provided when the depth of the web in a beam exceeds 750 mm. (0.1% of the web area and shall be distributed equally on two faces at a spacing not exceeding 300 mm or web thickness whichever is less).

41. The bond strength between steel reinforcement and concrete is affected by _____.

A) Steel properties
B) Concrete properties
C) Shrinkage of concrete

The correct answer is

A. A and B B. B and C
C. A and C D. A, B and C

Ans. D
Solution :

  • factors affecting bond strength b/w steel reinforcement & concrete

1) Grade of concrete
2) Properties of concrete
3) Properties of steel, commonly mild
steel is used.

  • Due to shrinkage of concrete, the bond with reinforcement improves. Concrete is tightly secured on the reinforcement surface.

42. The limits of percentage ‘p’ of the
longitudinal reinforcement in a
column is given by _______.(bars are
not lapped)

A. 0.15 % to 2 %
B. 0.8 % to 4 %
C. 0.8 % to 6 %
D. 0.8 % to 8 %

Correct Ans. C

Solution.

  • According to IS 456-800 Min area of steel = 0.8% of the gross area of the column Max area of steel = 6% of the gross area of column (if bars are not lapped)

43. Flash set of ordinary Portland cement paste is ______.

A. Premature hardening
B. Surface hardening only
C. Hardening without development of
heat of hydration
D. All the options are correct

Correct Ans. A

Solution :

  • Hardening refers to the gain of strength of a set of cement paste. Premature is done for ordinary Portland cement & process of hardening of cement Continues for a period more than one year.

44. The development of strength of
cement and its fineness are _______.

A. Directly proportional
B. Inversely proportional
C. Not related
D. Randomly related

Correct Ans. A

Solution:

  • Development of strength of cement depends on the porosity. So if w/c ratio increases it’s porosity increases & strength decreases & Fineness, or particle size of portland cement affects hydration rate and thus the rate of strength gain. The smaller the particle size, the greater the surface area-to-volume ratio, and thus, the more area available for water- cement interaction per unit volume.

45. The aggregate impact value of the
aggregate used in _______.

A. Building concrete is less than 45
B. Road pavement concrete is less
than 30
C. Runway concrete is less than 30
D. All the options are correct

Correct Ans. D

Solution:

  • In building there is no restriction of concrete, so we use 40mm or larger size aggregate impact value. & for road pavement & runway it should be less than 30.

46. Addition of sugar in concrete results
in _______.
A. Increase in setting time by about
1hr
B. Increase in setting time by about
4 hr
C. Decrease in setting time by about
1 hr
D. Decrease in setting time by about
4 hr

correct Ans. B

Solution.

  • Approximately 0.1 % sugar slows the rxn by ~ 5 hours. 0.2 % sugar slows the rxn by 9-11 hours.

47. For a satisfactory workable concrete
with a constant W.C. ratio increase in
aggregate cement ratio

A. Increases the strength of concrete
B. Decreases the strength of
concrete
C. No effect on the strength of
concrete
D. None of these

Correct Ans. B

Solution :

  • It was found that the compressive strength of the paving blocks decreased as the A/C ratio increased. The results also showed that the strength was directly proportional to the crushing strength of the aggregates (i.e., 10% fines value).

48. Steam curing is not used with
______.

A. Ordinary Portland cement
B. Rapid hardening cement
C. High alumina cement
D. All the options are correct

Correct Ans. C

Solution:

  • As per IS 6452, the steam curing or elevated temperature of curing shall be avoided.

49. The main object of compaction of
concrete is ______.

A. To eliminate air holes
B. To achieve maximum density
C. To get intimate contact between
the concrete and embedded material
D. All the options are correct

Correct Ans. D

Solutions.

  • The main purpose of the compaction is to increase the density & remove the air voids from the concrete. & after doing compaction we get a strong bond between concrete & embedded material because of after compaction the molecules of concrete becomes too close to each other.

50. In order to have segregation in
concrete dropping height should not
be more than ______.

A. 25 cm. B. 50 cm
C. 100 cm. D. 250 cm

Correct Ans. C

Solution.

  • The concrete shall be deposited as nearly as practicable in its final position to avoid rehandling. The concrete shall be placed and compacted before initial setting of concrete commences and should not be subsequently disturbed. Methods of placing should be such as to preclude segregation. Care should be taken to avoid displacement of reinforcement or movement of formwork. As a general guidance, the maximum permissible free fall of concrete may be taken as 1.5 m. Theoretically for drop placing it should not be more than 1 to 1.5 meter for well cohesively mixed concrete.

Important 1000 MCQ For CIVIL Junior Engineer : Part 2