RCC Structures Design MCQ Questions & Answers

1

Distribution of shear intensity over a rectangular section of a beam, follows:

A) A circular curve B) A straight line C) A parabolic curve D) An elliptical curve

Discuss

Answer & Solution

Answer: Option C

Solution:

Shear stress distribution in a rectangular cross-section of a beam is not uniform across the depth.

The intensity of shear stress is zero at the extreme top and bottom fibers and maximum at the neutral axis (center of the depth).

This distribution follows a parabolic curve, where the shape of the curve resembles a parabola with the vertex at the neutral axis.

This is derived from the shear stress formula in bending: τ = VQ / Ib, where τ is shear stress, V is shear force, Q is the first moment of area, I is the moment of inertia, and b is the width.

Hence, for rectangular sections, the resulting variation of τ across the depth is parabolic in nature.

Therefore, the correct answer is Option C: A parabolic curve.

2

If the shear stress in a R.C.C. beam is

A) Equal or less than 5 kg/cm², no shear reinforcement is provided B) Greater than 4 kg/cm², but less than 20 kg/cm², shear reinforcement is provided C) Greater than 20 kg/cm², the size of the section is changed D) All the above

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

3

In a pre-stressed 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

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

4

In a simply supported slab, alternate bars are curtailed at

A) $${\frac{1}{4}^{{\text{th}}}}$$ of the span B) $${\frac{1}{5}^{{\text{th}}}}$$ of the span C) $${\frac{1}{6}^{{\text{th}}}}$$ of the span D) $${\frac{1}{7}^{{\text{th}}}}$$ of the span

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

5

If L is the effective span of a R.C.C. beam which is subjected to maximum shear q_max at the ends, the distance from either end over which stirrups for the shear, are provided, is

A) $$\frac{{\text{L}}}{2}\left( {1 - \frac{3}{{{{\text{q}}_{\max }}}}} \right)$$ B) $$\frac{{\text{L}}}{3}\left( {1 - \frac{5}{{{{\text{q}}_{\max }}}}} \right)$$ C) $$\frac{{\text{L}}}{2}\left( {1 - \frac{5}{{{{\text{q}}_{\max }}}}} \right)$$ D) $$\frac{{\text{L}}}{2}\left( {1 - \frac{2}{{{{\text{q}}_{\max }}}}} \right)$$

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

6

Total pressure on the vertical face of a retaining wall of height h acts parallel to free surface and from the base at a distance of

A) $$\frac{{\text{h}}}{4}$$ B) $$\frac{{\text{h}}}{3}$$ C) $$\frac{{\text{h}}}{2}$$ D) $$\frac{{2{\text{h}}}}{3}$$

Discuss

Answer & Solution

Answer: Option B

No explanation is given for this question. Let's Discuss on Board

7

In a pre-stressed beam carrying an external load W with a bent tendon is having angle of inclination θ and pre-stressed load P. The net downward load at the centre is

A) W - 2P cosθ B) W - P cosθ C) W - P sinθ D) W - 2P sinθ

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

8

If the ratio of long and short spans of a two way slab with corners held down is r, the actual reduction of B.M. is given by

A) $$\frac{5}{6}\left( {\frac{{\text{r}}}{{1 + {{\text{r}}^2}}}} \right){\text{M}}$$ B) $$\frac{5}{6}\left( {\frac{{{{\text{r}}^2}}}{{1 + {{\text{r}}^2}}}} \right){\text{M}}$$ C) $$\frac{5}{6}\left( {\frac{{{{\text{r}}^2}}}{{1 + {{\text{r}}^3}}}} \right){\text{M}}$$ D) $$\frac{5}{6}\left( {\frac{{{{\text{r}}^2}}}{{1 + {{\text{r}}^4}}}} \right){\text{M}}$$

Discuss

Answer & Solution

Answer: Option B

Solution:

The question is about two-way slabs in Reinforced Cement Concrete (RCC) structures.

Two-way slabs are supported on all four sides and the load is carried in both directions (length and width).

The ratio 'r' refers to the ratio of the longer span to the shorter span of the slab.

When the corners of a two-way slab are held down (meaning they are prevented from lifting), it changes how the slab bends (its bending moment, or B.M.).

Because the corners are held down, the bending moment is reduced.

The question asks which formula correctly represents this reduction in bending moment.

The correct formula, representing the reduction, is: $$\frac{5}{6}\left( {\frac{{{{\text{r}}^2}}}{{1 + {{\text{r}}^2}}}} \right){\text{M}}$$ , where M is the original bending moment.

So, the answer is Option B.

9

An R.C.C beam of 25 cm width has a clear span of 5 metres and carries a U.D.L. of 2000 kg/m inclusive of its self weight. If the lever arm of the section is 45 cm., the beam is

A) Safe in shear B) Is safe with stirrups C) Is safe with stirrups and inclined members D) Needs revision of the section

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

10

The minimum clear cover for R.C.C. columns shall be

A) Greater of 40 mm or diameter B) Smaller of 40 mm or diameter C) Greater of 25 mm or diameter D) Smaller of 25 mm or diameter

Discuss

Answer & Solution

Answer: Option A

Solution:

1. Definition of Clear Cover:
The clear cover is the distance between the outer surface of the reinforcement and the exposed surface of the concrete.

2. Importance of Clear Cover in RCC Columns:
It provides protection to reinforcement against corrosion and fire exposure.
Ensures proper bond strength between concrete and reinforcement.

3. Standard Requirement:
As per IS 456:2000, the minimum clear cover for RCC columns should be the greater of 40 mm or the diameter of the bar used in reinforcement.
This ensures sufficient durability and structural integrity under various environmental conditions.

Conclusion:
The correct answer is Option A: Greater of 40 mm or diameter, as per standard RCC design guidelines.

RCC Structures Design MCQ Questions & Answers | Civil Engineering