SSC-JUNIOR ENGINEER (Civil & Structural) Online Exam 2016 (Part-II)

Total Questions: 50

31. The slope of curve of S.F.D (Shear Force Diagram) at any section will be equal to _________.

Correct Answer: B. the ordinate of loading diagram at the section
Solution:Shear force and bending moment in a beam vary from section to section. The graphical representation of shear force in which ordinate represents shear force and the abscissa represents the position of the section is called Shear Force Diagram (SFD).

The diagram in which the ordinate represents bending moment and the abscissa represents the position of the section is called Bending Moment Diagram (BMD).

These diagrams are usually located below the load diagram.

From equations, it may be concluded that the rate of change of shear force (slope of shear force diagram curve) at any section is equal to the intensity of loading at that section and the rate of change of bending moment (i.e., slope of bending moment diagram curve) is equal to the shear force at that section. From equation it can also be concluded that the bending moment will be maximum/minimum where shear force (dM/dx) is zero.

32. The two criteria for the determination of allowable bearing capacity of a foundation are _________.

Correct Answer: D. shear failure and settlement
Solution:The criteria for the determination of bearing capacity of a foundation, which are based on the requirements for stability, are as follows:

(i) Shear failure, or bearing capacity failure as it is sometimes called, shall not occur. This is associated with plastic flow and lateral expulsion of the soil beneath the foundation (shear strength criterion).

(ii) The anticipated settlements, differential as well as total, of the foundation shall be less than the safe or tolerable values, so that the stability of the structure is not impaired (settlement criterion).

These two criteria are independent of each other. The design value of the safe bearing capacity is obviously the smaller of the values obtained from these two criteria. This has already been defined as the allowable bearing pressure.

33. The working stress (in N/mm²) for structural steel in tension is the order of _________.

Correct Answer: C. 150
Solution:No explanation given in the book

34. If the storey height is equal to length of RCC wall, the percentage increase in strength is ________.

Correct Answer: B. 10
Solution:No explanation given in the book

35. In constructions, why are the lintels preferred to arches?

(a) Arches will not last long

(b) Arches require more head room to span the openings like doors, windows, etc.

(c) Arches require strong abutments to withstand arch thrust

Correct Answer: D. Both (b) and (c)
Solution:Arch and lintel are provided above doors, windows and passages. The function of an arch and a lintel is to carry the weight of the structure above the opening. In an arch because of the shape, the blocks support each other by the mutual pressure of their own weight and the structure remains in position by the resistance from the supports. Special types of centring devices are incorporated.

A lintel is a horizontal member used to span openings in walls. It functions similar to that of an arch. Lintels provided over windows are connected to a sunshade to provide shade and shelter. Centring for lintels are much simpler than that of arches.

In constructions, lintels are preferred to arches because arches require strong abutments to withstand arch thrust and arches require more head room to span the openings like doors, windows, etc.

36. For a design of a simply supported beam under uniformly distributed load ________.

Correct Answer: B. check the section at centre for Bending Moment and at the support for shear
Solution:For a design of a simply supported beam under uniformly distributed load check the section at centre for Bending Moment and at the support for shear.

37. What does the influence line for Bending Moment indicate?

(a) Bending Moment at any section on the structure for a given positions of load.

(b) Bending Moment at a given section for any position of a point load.

Correct Answer: B. Only (b)
Solution:An influence line for a function (e.g., moment, shear, reaction, deflection, etc.) in a structure is a curve which shows its variation at a particular section of the structure for various positions of a moving unit point load.

The influence line for bending moment (shear force) must not be confused with the bending moment (shear force) diagram for the structure. Whereas the BMD (SFD) shows the moment (shear) values at all sections of the structure, the influence line for BM (SF)-always drawn for a moving unit point load and for a particular section only-is a curve whose ordinate at any arbitrary point on the structure determines the moment (shear) value at the particular section for which the IL has been drawn when the unit load intercepts the said ordinate.

38. The minimum percentage of shear reinforcement in R.C.C beams is _________.

Correct Answer: D.
Solution:No explanation given in the book

39. The maximum allowable percentage of tension reinforcement in R.C.C. beams is _________.

Correct Answer: C.
Solution:In IS 456 : 2000 Clause 26, requirements related to reinforcement used in RCC is given. As per the clause,

In Beam

1. Longitudinal reinforcement,

Min percentage of reinforcement should be (cl. 26.5.1.1)
As = 0.85 bd/fy
Max percentage of reinforcement (both compression and tension steel) should be 4% of cross sectional area of beam (cl. 26.5.1.2), i.e.,
AS = 0.04 bD

2. Side face reinforcement, (cl.26.5.1.3)

Side face reinforcement if needed shall not be less than 0.1% of web area.

3. Shear reinforcement, (cl.26.5.1.5)

Now min and max SR decide from the c/c spacing for SR.

40. The maximum diameter of the reinforcement bars in R.C.C. slabs is _________.

Correct Answer: D. Thickness of slab/8
Solution:Reinforcement detailing of a slab is done based on its support conditions. Slab may be supported on walls or beams or columns.

The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less.