Design Concrete Structures Part 2: Multiple Choice Questions

Multiple-Choice Questions answer related to Design And Structures. Design Concrete Structures Part 2 consists of 75 MCQs on Design Concrete Structure. See Design Concrete Structure Part 1 for more MCQs on this topic.

 

Design Concrete Structures Part 2

 

The average permissible stress in bond for plain bars in tension is ??

a. decreased by 25% for bars in compression
b. decreased by 10% for bars in compression
c. increased by 25% for bars in compression
d. increased by 10% for bars in compression

 

The minimum cover to the ties or spirals should not be less than ??

a. 50mm
b. 25 mm
c. 20 mm
d. 15 mm

 

Maximum distance between expansion joints in structures as per IS: 456 – 1978 is ??

a. 60 m
b. 45 m
c. 30 m
d. 20 m

 

Maximum percentage reinforcement in case of slabs is limited to ??

a. 8
b. 6
c. 4
d. 2

 

A higher modular ratio shows ??

a. lower tensile strength of steel
b. higher tensile strength of steel
c. lower compressive strength of concrete
d. higher compressive strength of concrete

 

The diameter of ties in a column should be ??

a. more than 5 mm and also more than one-fourth of the diameter of the main bar
b. more than 5 mm but less than one-fourth of the diameter of the main bar
c. more than or equal to 5 mm
d. more than or equal to one-fourth of the diameter of the main bar

 

The ratio of permissible stress in direct compression and bending compression is ??

a. greater than 2
b. between 1.5 and 2.0
c. between 1 and 1.5
d. less than 1

 

The minimum diameter of longitudinal bars in a column is ??

a. 16 mm
b. 12 mm
c. 8 mm
d. 6 mm

 

In working stress design, permissible bond stress in the case of deformed bars is more than that in plain bars by ??

a. 40%
b. 30%
c. 20%
d. 10%

 

For the design of retaining walls, the minimum factor of safety against overturning is taken as ??

a. 3.0
b. 2.5
c. 2.0
d. 1.5

 

MCQs Part 2

 

Half of the main steel in a simply supported slab is bent up near the support at a distance of x from the center of slab bearing where x is equal to ??
where 1 is the span

a. 1/10
b. 1/7
c. 1/5
d. 1/3

 

The load-carrying capacity of a helically reinforced column as compared to that of a tied column is about ??

a. 10% more
b. 5% more
c. 10% less
d. 5% less

 

 If the size of the panel in a flat slab is 6m x 6m, then as per Indian Standard Code, the widths of column strip and middle strip are ??

a. 1.5 m and 1.5 m
b. 3.0 m and 3.0 m
c. 1.5 m and 3.0 m
d. 3.0 m and 1.5 m

 

Due to circumferential action of the spiral in a spirally reinforced column ??

a. both the capacity of column and ductility of column increase
b. the capacity of the column is decreased but ductility of column increases
c. the capacity of the column is decreased
d. the capacity of the column is decreased

 

The permissible diagonal tensile stress in reinforced brickwork is ??

a. about 1.0 N/mm2
b. 0.3 N/mm2 to 0.7 N/mm2
c. zero
d. about 0.1 N/mm2

 

Which of the following R.C. retaining walls is suitable for heights beyond 6m ??

a. counterfort type
b. T-shaped wall
c. L-shaped wall
d. all of the above

 

When shear stress exceeds the permissible limit in a slab, then it is reduced by ??

a. using thinner bars but more in number
b. using high strength steel
c. providing shear reinforcement
d. increasing the depth

 

The temperature reinforcement in the vertical slab of a T-shaped R.C. retaining wall is ??

a. provided more on the front face than on inner face
b. provided more on the inner face than on front face
c. provided equally on inner and front faces
d. not needed

 

The main reason for providing a number of reinforcing bars at support in a simply supported beam is to resist in that zone ??

a. tensile stress
b. bond stress
c. shear stress
d. compressive stress

 

In a pile of length /, the points of suspension from ends for lifting it are located at ??

a. 0.333 /
b. 0.293 /
c. 0.25 /
d. 0.207 1

 

Design Concrete Structures Part 2

 

For a slab supported on its four edges with corners held down and loaded uniformly, the Marcus correction factor to the moments obtained by Grashoff Rankine’s theory ??

a. can be less than 1
b. can be more than 1
c. is always greater than 1
d. is always less than 1

 

While designing the pile as a column, the end conditions are nearly ??

a. one end fixed and other end free
b. one end fixed and other end hinged
c. both ends fixed
d. both ends hinged

 

Modulus of elasticity of steel as per IS: 456-1978 shall be taken as ??

a. 2xl06N/cm2
b. 200kN/mm2
c. 200 kN/cm2
d. 20 kN/cm2

 

The critical section for finding a maximum bending moment for footing under the masonry wall is located ??

a. at a distance equal to the effective depth of footing from the edge of the wall
b. halfway between the middle and edge of the wall
c. at the edge of the wall
d. at the middle of the wall

 

If the depth of the neutral axis for a singly reinforced rectangular section is represented by kd in working stress design, then the value of k for balanced section ??

a. is independant of both ast and acbc where d is the effective depth, ast is permissible stress in steel in tension and ocbc is permissible stress in c
b. depends on both crst and acbc
c. depends on aCbC only
d. depends on as, only

 

If the foundations of all the columns of a structure are designed on the total live and dead load basis, then ??

a. the settlement of interior columns will be more than exterior columns
b. the settlement of exterior columns will be more than interior columns
c. there will be no differential settlement
d. there will be no settlement of columns

 

If nominal shear stress tv exceeds the design shear strength of concrete xc, the nominal shear reinforcement as per IS: 456-1978 shall be provided for carrying shear stress equal to ??

a. Tv + Tc
b. xv – TC
c. xc
d. xv

 

During an erection, the pile of length / is supported by a crane at a distance of ??

a. 0.793 /
b. 0.7071
c. 0.293 /
d. 0.207 /

 

For a reinforced concrete section, the shape of the shear stress diagram is ??

a. rectangular above neutral axis and parabolic below neutral axis
b. parabolic above neutral axis and rectangular below neutral axis
c. wholly rectangular
d. wholly parabolic

 

According to ISI recommendations, the maximum depth of stress block for a balanced section of a beam of effective depth d is ??

a. 0.85 d
b. 0.68 d
c. 0.55 d
d. 0.43 d

 

Design Concrete Structures Part 2

 

The main reinforcement in the heel of a T-shaped R.C. retaining wall is provided on ??

a. both top and bottom face perpendicular to wall
b. bottom face perpendicular to wall
c. top face perpendicular to wall
d. none of the above

 

 The centroid of compressive force, from the extreme compression fiber, in limit state design lies at a distance of ?? Where xu is the depth of the neutral axis at the limit state of collapse

a. 0.573 xu
b. 0.446 xu
c. 0.416 xu
d. 0.367 xu

 

In counterfort retaining walls, the main reinforcement in the stem at support is ??

a. provided both on inner and front faces
b. provided only on front face
c. provided only on inner face
d. not provided

 

The load factors for live load and dead load are taken respectively as ??

a. 2.2 and 2.2
b. 1.5 and 1.5
c. 2.2 and 1.5
d. 1.5 and 2.2

 

In a counterfort retaining wall, the main reinforcement in the stem at mid-span is provided on ??

a. both front face and inner face
b. an inner face only
c. the front face only
d. none of the above

 

According to Whitney’s theory, the ultimate strain of concrete is assumed to be ??

a. 3%
b. 0.3%
c. 0.1%
d. 0.03%

 

A T-shaped retaining wall mainly consists of ??

a. four cantilevers
b. three cantilevers
c. two cantilevers
d. one cantilever

 

Assertion A: The load factor for the live load is greater than that for the dead load. Reason R: The live loads are more uncertain than dead loads?
Select your answer based on the coding system given below ??

a. A is false but R is true
b. A is true but R is false
c. Both A and R are true but R is not the correct explanation of A
d. Both A and R are true and R is the correct explanation of A

 

To minimize the effect of differential settlement, the area of a footing should be designed for ??

a. live load + fraction of dead load
b. dead load + fraction of live load
c. dead load + live load
d. dead load only

 

Stress-strain curve of high tensile steel ??

a. does not show definite yield point but yield point is defined by 2% proof stress
b. does not show definite yield point but yield point is defined by 0.2% proof stress
c. does not show definite yield point but yield point is defined by 0.1% proof stress
d. has a definite yield point

 

Design Concrete Structures Part 2

 

The design yield stress of steel according to IS: 456-1978 is ??
where fy is the characteristic yield strength of steel

a. 0.87 fy
b. 0.67 fy
c. 0.57 fy
d. 0.37 fy

 

Cube strength of controlled concrete to be used for pre-tensioned and post-tensioned work respectively should not be less than ??

a. 53 MPa and 42 MPa
b. 42 MPa and 53 MPa
c. 42 MPa and 35 MPa
d. 35 MPa and 42 MPa

 

According to Whitney’s theory, the depth of stress block for a balanced section of a concrete beam is limited to ?? Where d is the effective depth of beam[ES 2k]

a. 0.85 d
b. 0.68 d
c. 0.537 d
d. 0.43 d

 

The ultimate strength of cold-drawn high steel wires ??

a. decreases with an increase in diameter of bar
b. does not depend on the diameter of bar
c. increases with an increase in diameter of bar
d. none of the above

 

As per Whitney’s theory, the maximum moment of resistance of the balanced section of a beam of width b and effective depth d is given by ??

a. 0.43acybd2
b. 0.185acybd2
c. ^acybd2
d. ^acybd2

 

High carbon content in the steel causes ??

a. increase in both tensile strength and ductility
b. decrease in both tensile strength and ductility
c. increase in tensile strength but a decrease in ductility
d. decrease in tensile strength but increase in ductility

 

Due to shrinkage stresses, a simply supported beam having reinforcement only at the bottom tends to ??

a. deflect downward or upward
b. deflect upward
c. deflect downward
d. none of the above

 

Prestress loss due to friction occurs ??

a. in both post-tensioned and pre-tensioned beams
b. only in pre-tensioned beams
c. only in post-tensioned beams
d. none of the above

 

A beam curved in the plan is designed for ??

a. bending moment, shear, and torsion
b. shear and torsion
c. bending moment and torsion
d. bending moment and shear

 

A most common method of prestressing used for factory production is ??

a. Lee-Macall system
b. Magnel-Blaton system
c. Freyssinet system
d. Long line method

 

Design Concrete Structures Part 2

 

In a spherical dome, the hoop stress due to a concentrated load at the crown is ??

a. tensile everywhere
b. partly compressive and partly tensile
c. compressive everywhere
d. zero

 

The purpose of reinforcement in prestressed concrete is ??

a. to impart initial compressive stress in concrete
b. to resist tensile stresses
c. to provide adequate bond stress
d. all of the above

 

In prestressed concrete ??

a. both forces of tension and compression, as well as lever arm, remain unchanged
b. both forces of tension and compression as well as lever arm change
c. forces of tension and compressions remain unchanged but the lever arm changes with the moment
d. forces of tension and compression change but lever arm remains unchanged

 

The maximum value of hoop compression in a dome is given by ??
where, w = load per unit area of surface of dome R = radius of curvature d = thickness of dome

a. 2wR/d
b. wR/d
c. wR/2d
d. wR / 4d

 

Normally prestressing wires are arranged in the ??

a. anywhere
b. center
c. lower part of the beam
d. upper part of the beam

 

In a spherical dome subjected to a concentrated load at the crown or uniformly distributed load, the meridional force is always ??

a. tensile or compressive
b. compressive
c. tensile
d. zero

 

Which of the following losses of prestress occurs only in pretensioning and not in post-tensioning ??

a. loss due to friction
b. creep of concrete
c. shrinkage of concrete
d. elastic shortening of concrete

 

 In symmetrically reinforced sections, shrinkage stresses in concrete and steel are respectively ??

a. both tensile
b. both compressive
c. tensile and compressive
d. compressive and tensile

 

Which of the following has high tensile strength ??

a. all have the same tensile strength
b. heat-treated rolled wires
c. cold drawn wires
d. plain hot rolled wires

 

The effect of creep on modular ratio is ??

a. to keep it unchanged
b. either to decrease or to increase it
c. to increase it
d. to decrease it

 

Design Concrete Structures Part 2

 

The recommended value of the modular ratio for reinforced brickwork is ??

a. 58
b. 40
c. 30
d. 18

 

In T-shaped R C. retaining walls, the main reinforcement in the stem is provided on ??

a. the inner face in both directions
b. the inner face in one direction
c. the front face in both directions
d. the front face in one direction

 

Select the correct statement ??

a. High tensile steel is cheaper than mild steel
b. carbon percentage in high carbon steel is less than that in mild steel
c. Elastic modulus of high tensile steel is more than that of mild steel
d. Elastic modulus of high tensile steel is nearly the same as that of mild steel

 

Select the incorrect statement ??

a. Bleeding can be increased by addition ‘of calcium chloride
b. Bleeding can be minimized by adding pozzuolana finer aggregate
c. Lean mixes bleed more as compared to rich ones
d. none of the above

 

The effect of adding calcium chloride in concrete is ________________ ??
1. to increase shrinkage
2. to decrease shrinkage
3. to increase the setting time
4. to decrease setting time
The correct answer is ??

a. (2) and (4)
b. (2) and (3)
c. (1) and(4)
d. (1) and (3)

 

Examine the following statements ??

1. Factor of safety for steel should be based on its yield stress,
2. Factor of safety for steel should be based on its ultimate stress,
3. Factor of safety for concrete should be based on its yield stress,
4. Factor of safety for concrete should be based on its ultimate stress.
The correct statements are ??

a. (2) and (4)
b. (2) and (3)
c. (1) and (4)
d. (1) and (3)

 

In counterfort type retaining walls ??
1. the vertical slab is designed as a continuous slab
2. the heel slab is designed as a continuous slab
3. the vertical slab is designed as a cantilever
4. the heel slab is designed as a cantilever
The correct answer is ??

a. (3) and (4)
b. (2) and (3)
c. (1) and(4)
d. (1) and (2)

 

The main reinforcement in the toe of a T- shaped R C. retaining wall is provided on ??
1. top face parallel to the wall
2. top face perpendicular to the wall
3. bottom face parallel the wall
4. bottom face perpendicular to the wall
The correct answer is ??

a. only (4) is correct
b. (3) and (4) are correct
c. (1) and (2)are correct
d. only (2) is correct

 

In a counterfort retaining wall, the main reinforcement is provided on the ??

1. bottom face in front counterfort
2. inclined face in front counterfort
3. bottom face in back counterfort
4. inclined face in back counterfort
The correct answer is ??

a. (3) and (4)
b. (1) and (4)
c. (2) and (3)
d. (1) and (2)

 

Select the incorrect statement ??

a. For heavy loads and large spans in buildings or bridges, a post-tensioning system is cheaper than a pre-tensioning system
b. Pre-tensioning system has greater certainty about its durability
c. The loss of prestressing is more in the pre-tensioning system than in the post-tensioning system
d. none of the above

 

Design Concrete Structures Part 2

 

In a ring beam subjected to uniformly distributed load ??

1. shear force at mid-span is zero
2. shear force at mid-span is maximum
3. torsion at mid-span is zero
4. torsion at mid-span is maximum
The correct answer is ??

a. (2) and (4)
b. (2) and (3)
c. (1) and (4)
d. (1) and (3)

 

The sinking of intermediate support of a continuous beam ??

1. reduces the negative moment at support
2. increases the negative moment at support
3. reduces the positive moment at the center of the span
4. increases the positive moment at the center of the span
The correct answer is ??

a. (2) and (4)
b. (2 )and (3)
c. (1) and (4)
d. (1) and (3)

 

Shrinkage of concrete depends upon ??

1. humidity of the atmosphere
2. passage of time
3. stress
The correct answer is ??

a. All (1), (2), and (3)
b. only (3)
c. (2)and (3)
d. (1) and (2)

 

The depth of footing for an isolated column is governed by ??

1. maximum bending moment
2. shear force
3. punching shear
The correct answer is ??

a. (1), (2), and (3)
b. (1) and (3)
c. (1) and (2)
d. only (1)

 

In the design of a front counterfort in a counterfort retaining wall, the main reinforcement is provided on ??

1. bottom face near counterfort
2. top face near counterfort
3. bottom face near center of the span
4. top face near center of span The correct answer is ??

a. both (2)and (3)
b. both (1) and (4)
c. only (2)
d. only (1)

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