Reinforcement Cement Concrete (General Engineering) (SSC JE)

Total Questions: 56

31. In RCC beams, as the percentage area of tensile steel increases– [RRB JE 26.08.2015 (Shift-I) ]

Correct Answer: (a) Depth of neutral axis increases
Solution:

If, percentage are of tensile steel increases than depth of neutral axis increases.
Types of section beam–
1. Balanced section beam–
• If depth of neutral axis is equal to depth of limiting
neutral axis.
2. Under reinforced section beam–
• If depth of neutral axis is less than depth of limiting
neutral axis.
3. Over reinforced beam–

32. The maximum percentage of moment redistribution allowed in RCC beams is– [RRB JE 26.08.2015 (Shift-II) ]

Correct Answer: (c) 30%
Solution:

As per IS 456 : 2000- the redistribution of moments may be carried out satisfying the following conditions.

(a) Equilibrium between the internal forces and the external loads is maintained.

(b) The ultimate moment of resistance provided at any section of a member is not less than 70% of the moment at that section obtained from an elastic maximum moment diagram covering all appropriate combination of loads.

(c) The elastic moment at any section in a member due to a particular combination of loads shall not be reduced by more than 30% of the numerically largest moments given anywhere by the elastic maximum moments diagrams for the particular member, covering all appropriate combination of loads.

33. For M-20 grade of concrete, the maximum shear stress shall not exceed : [RRB JE 27.08.2015 (Shift-II) ]

Correct Answer: (c) 2.8 N/mm²
Solution:

34. The stress below which a material has a high probability of not failing under reversal of stress is known as : [RRB JE 27.08.2015 (Shift-II) ]

Correct Answer: (d) Endurance limit
Solution:

Endurance limit–
• Endurance limit is the stress level below which even a large number of stress cycles can not produce fatigue failure.

Fatigue–The deformation of a material due to the repeated cycle of stress and strain resulting in progressive cracking.

35. The term nominal stress in stress-strain curve for mild steel implies– [RRB JE 27.08.2015 (Shift-III)]

Correct Answer: (a) Average stress
Solution:

The term nominal stress in stress-strain curve for mild steel implies the average stress that is calculated by dividing the applied load by the original cross-sectional area of the specimen.

36. Minimum grade of concrete to be used in reinforced concrete is– [RRB JE 27.08.2015 (Shift-III) ]

Correct Answer: (c) M 20
Solution:

According to IS code 456 : 2000–
• Minimum grade of concrete to be used in reinforced concrete is M20.
According to IS code 456 : 1978– •
Minimum grade of concrete to be used in reinforced concrete is M15.

37. How is the deflection in RC beams controlled as per IS : 456 ? [RRB JE 28.08.2015 (Shift-II)]

Correct Answer: (c) By controlling span/depth ratio
Solution:

According to IS 456-2000 clearly states that the control of deflection is governed by suitable a value which is span to effective depth ratios.

38. In the conventional pre-stressing, the diagonal tension in concrete– [RRB JE 29.08.2015 (Shift-III) ]

Correct Answer: (b) decreases
Solution:

• In the conventional prestressing, the diagonal tension reduces as whole section is under compression generally in prestressing

39. The reinforced concrete beam curved in plan is designed for– [RRB JE 29.08.2015 (Shift-I) ]

Correct Answer: (d) Bending moment, shear and torsion
Solution:

• A reinforced concrete beam curved in the plane is structural element that is subjected to different types of loads. The loads can cause the beam to bend, shear or twist.

40. Permissible shear stress in concrete is a function of– [RRB JE 29.08.2015 (Shift-II) ]

Correct Answer: (d) Percentage of steel reinforcement and grade of concrete
Solution:

The permissible shear stress in concrete is a function of the percentage of steel reinforcement and the grade of concrete.
• The higher percentage of steel reinforcement and the grade of concrete, the higher the permissible shear stress.