Question 1

The maximum ratio of span to depth of a slab simply supported and spanning in one direction, is
A)35
B)25
C)30
D)20

Accepted Answer

The maximum ratio of span to depth of a slab simply supported and spanning in one direction is 30. This is because the bending moment in a simply supported slab is proportional to the square of the span, and the moment of inertia of the slab is proportional to the cube of the depth. Therefore, the ratio of span to depth must be kept below a certain value to prevent the slab from failing in bending.

Question 2

If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is
A)Square
B)Rectangular
C)Trapezoidal
D)Triangular

Accepted Answer

When the width of the foundation for two equal columns is restricted, a rectangular footing is generally adopted to efficiently distribute the load within the available space.

Question 3

The floor slab of a building is supported on reinforced cement floor beams. The ratio of the end and intermediate spans is kept
A)0.7
B)0.8
C)0.9
D)0.6

Accepted Answer

The ratio of the end span to the intermediate span in reinforced concrete floor beams is typically kept at 0.9 to ensure structural stability and uniform load distribution.

Question 4

A pre-stressed concrete member is preferred because
A)Its dimensions are not decided from the diagonal tensile stress
B)Large size of long beams carrying large shear force need not be adopted
C)Removal of cracks in the members due toshrinkage
D)All the above

Accepted Answer

Pre-stressed concrete members are preferred because they address all the issues mentioned: they are not limited by diagonal tensile stress, they allow for smaller beam sizes under large shear forces, and they help in reducing shrinkage cracks.

Question 5

If the ratio of the span to the overall depth does not exceed 10, the stiffness of the beam will ordinarily be satisfactory in case of a
A)Simply supported beam
B)Continuous beam
C)Cantilever beam
D)None of these

Accepted Answer

The answer of If the ratio of the span to...

Question 6

A pile of length carrying a uniformlydistributed load per metre length is suspended at two points, the maximum, B.M. at the centre of the pile or at the points of suspension, is
A)WL/8
B)WL²/24
C)WL²/47
D)WL²/16

Accepted Answer

The answer of A pile of length carrying a uniformlydistributed...

Question 7

If is the net upward pressure on a square footing of side for a square column of side , the maximum bending moment is given by
A)B.M = pb (c - a)/4
B)B.M = pb (b -a)²/4
C)B.M = pb (b -a)²/8
D)B.M = pb (b +a)/8

Accepted Answer

The maximum bending moment for a square footing under a square column, considering uniform pressure distribution, is given by the formula $B.M = \frac{pb(b - a)^2}{8}$, where $p$ is the pressure, $b$ is the side of the footing, and $a$ is the side of the column. This formula accounts for the difference in dimensions between the footing and the column, and the division by 8 is due to the distribution of forces and the calculation of moments for a square shape.

Question 8

longitudinal bars and lateral stirrups, is
A)Stress in concrete × area of concrete
B)Stress in steel × area ofsteel
C)Stress in concrete × area of concrete + Stress in steel × area of steel
D)None of these

Accepted Answer

The correct answer is C because it accounts for the composite action of reinforced concrete, where both the concrete (in compression) and the steel reinforcement (in tension) contribute to the overall strength of the member.

Question 9

If p₁ and p² are mutually perpendicular principal stresses acting on a soil mass, the normal stress on any plane inclined at angle ?? to the principal plane carrying the principal stress p₁, is: A) (p₁ ? p²)/2+ (p₁ + p²)/2 sin 2? B) (p₁ ? p²)/2+ (p₁ + p²)/2 cos 2? C) (p₁ + p²)/2+ (p₁ ? p²)/2 cos 2? D) (p₁ + p²)/2+ (p₁ ? p²)/2 sin 2?

Accepted Answer

The normal stress on any plane inclined at an angle to the principal plane can be found using the formula $\sigma_n = \frac{\sigma_1 + \sigma_2}{2} + \frac{\sigma_1 - \sigma_2}{2} \cos 2\theta$, where $\sigma_1$ and $\sigma_2$ are the principal stresses and $\theta$ is the angle of inclination. This matches option C.

Question 10

The minimum thickness of the cover at the end of a reinforcing bar should not be less than twice the diameter of the bar subject to a minimum of
A)10 mm
B)15 mm
C)20 mm
D)25 mm

Accepted Answer

The answer of The minimum thickness of the cover at...

Question 11

is the pre-stressed force applied to tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is. The minimum stress on the beam subjected to a maximum bending moment is
A)f = (P/A) -(Z/M)
B)f = (A/P) -(M/Z)
C)f = (P/A) - (M/Z)
D)f = (P/A) - (M/6Z)

Accepted Answer

The correct formula for the minimum stress on a beam subjected to a maximum bending moment, considering pre-stressing force (P), area of cross-section (A), maximum bending moment (M), and sectional modulus (Z), is $f = \frac{P}{A} - \frac{M}{Z}$. This accounts for both the uniform compressive stress due to the pre-stressing force and the bending stress due to the applied moment.

Question 12

If C is creep coefficient, f is original pre-stress in concrete, m is modular ratio, E is Young's modulus of steel and e is shrinkage strain, the combined effect of creep and shrinkage is:
A)(1 - C)mf - eE
B)(C - 1)mf + eE
C)(C - 1)mf - eE
D)(1 - C)mf + eE

Accepted Answer

The combined effect of creep and shrinkage in concrete can be represented by the formula $(C - 1)mf + eE$, where $C$ is the creep coefficient, $m$ is the modular ratio (ratio of modulus of elasticity of steel to that of concrete), $f$ is the original pre-stress in the concrete, and $eE$ represents the effect of shrinkage strain multiplied by the modulus of elasticity of steel. This formula accounts for the increase in strain due to creep ($C - 1)mf$ and the additional strain from shrinkage ($eE$).

Question 13

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

Accepted Answer

In pre-stressed concrete, using high strength concrete along with high tensile steel is advisable because high strength concrete can resist high compressive stresses, while high tensile steel can withstand the high tensile stresses induced by the pre-stressing force, leading to a more durable and efficient structural component.

Question 14

An R.C.C. lintel is spanning an opening of 2 m span in a brick wall. The height of the roof is 2.9 m above the floor level and that of the opening is 2.1 m above the floor level. The lintel is to be designed for self weight plus
A)Triangular load of the wall
B)UDL of wall
C)UDL of wall + load from the roof
D)Triangular load + load from the roof

Accepted Answer

The lintel should be designed for its self weight plus a Uniformly Distributed Load (UDL) of the wall and the load from the roof. This is because the lintel supports the masonry above the opening and any loads that are transmitted from the roof to the wall above the opening.

Question 15

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

Accepted Answer

The answer of The minimum clear cover for R.C.C. columns...

Question 16

An R.C.C beam of 25 cm width has a clear span of 5 metres and carries a U.D.L. of 2000kg/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 inclinedmembers
D)Needsrevision ofthe section

Accepted Answer

The beam is considered safe in shear if the shear stress does not exceed the permissible stress for the material, which is determined by the beam's dimensions, the applied load, and the lever arm. Given the information, there's no indication that the shear stress exceeds the permissible limits, hence the beam can be considered safe in shear without additional details on material properties and calculations. Stirrups and inclined members are typically added to enhance shear capacity or when there's a known deficiency, which isn't explicitly mentioned here.

Question 17

If the bearing capacity of soil is 10 tonnes/cm² and the projection of plain concrete footing from walls, is a cm, the depth D of footing is A)D = 0.0775 a B)D = 0.775 a C)D = 0.775 ?a D)D = 0.775 a²

Accepted Answer

The depth of footing (D) in relation to the projection (a) for plain concrete footing, considering the bearing capacity of soil, is typically calculated based on empirical formulas or design principles that take into account factors such as the soil's bearing capacity, the load from the structure, and safety factors. The correct formula does not include complex symbols or operations such as square roots or powers, making option B (D = 0.775 a) the correct choice as it directly relates the depth of footing to the projection with a simple proportionality factor.

Question 18

After pre-stressing process is completed, a loss of stress is due to
A)Shrinkage of concrete
B)Elastic shortening of concrete
C)Creep of concrete
D)All the above

Accepted Answer

After the pre-stressing process is completed, a loss of stress occurs due to shrinkage of concrete, elastic shortening of concrete, and creep of concrete. These factors collectively contribute to the reduction in pre-stress over time.

Question 19

In a simply supported slab, alternate bars are curtailed at A)1/4^th of the span B)1/5^th of the span C)1/6^th of the span D)1/7^th of the span

Accepted Answer

The answer of In a simply supported slab, alternate bars...

Question 20

If R and T are rise and tread of a stair spanning horizontally, the steps are supported by a wall on one side and by a stringer beam on the other side, the steps are designed as beams of width
A)R + T
B)T - R
C)$\sqrt{R^{2}+T^{2}}$
D)R - T

Accepted Answer

The steps can be considered as beams spanning from the wall to the stringer beam. The effective span or width of these beams is the hypotenuse of a right-angled triangle formed by the rise (R) and tread (T), which is calculated using the Pythagorean theorem as $\sqrt{R^{2}+T^{2}}$.

Quiz 1: Concrete Design and Construction

The maximum ratio of span to depth of a slab simply supported and spanning in one direction, is

If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is

The floor slab of a building is supported on reinforced cement floor beams. The ratio of the end and intermediate spans is kept

A pre-stressed concrete member is preferred because

If the ratio of the span to the overall depth does not exceed 10, the stiffness of the beam will ordinarily be satisfactory in case of a

A pile of length carrying a uniformlydistributed load per metre length is suspended at two points, the maximum, B.M. at the centre of the pile or at the points of suspension, is

If is the net upward pressure on a square footing of side for a square column of side , the maximum bending moment is given by

longitudinal bars and lateral stirrups, is

If p1 and p2 are mutually perpendicular principal stresses acting on a soil mass, the normal stress on any plane inclined at angle ?? to the principal plane carrying the principal stress p1, is:

The minimum thickness of the cover at the end of a reinforcing bar should not be less than twice the diameter of the bar subject to a minimum of

is the pre-stressed force applied to tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is. The minimum stress on the beam subjected to a maximum bending moment is

If C is creep coefficient, f is original pre-stress in concrete, m is modular ratio, E is Young's modulus of steel and e is shrinkage strain, the combined effect of creep and shrinkage is:

In a pre-stressed member it is advisable to use

An R.C.C. lintel is spanning an opening of 2 m span in a brick wall. The height of the roof is 2.9 m above the floor level and that of the opening is 2.1 m above the floor level. The lintel is to be designed for self weight plus

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

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

If the bearing capacity of soil is 10 tonnes/cm2 and the projection of plain concrete footing from walls, is a cm, the depth D of footing is

After pre-stressing process is completed, a loss of stress is due to

In a simply supported slab, alternate bars are curtailed at

If R and T are rise and tread of a stair spanning horizontally, the steps are supported by a wall on one side and by a stringer beam on the other side, the steps are designed as beams of width

If p₁ and p² are mutually perpendicular principal stresses acting on a soil mass, the normal stress on any plane inclined at angle ?? to the principal plane carrying the principal stress p₁, is:

If the bearing capacity of soil is 10 tonnes/cm² and the projection of plain concrete footing from walls, is a cm, the depth D of footing is