# Design Concrete Structures Part 1: Multiple Choice Question

Multiple-Choice Questions on Design Concrete Structures. Design Concrete Structures Part 1 has 60 MCQs related to designs of Concrete Structures with Answers.

## Design Concrete Structures Part 1

Increase in the moisture content in concrete ??

a. does not change the strength
b. increases the strength
c. reduces the strength
d. all of the above

The property of the ingredients to separate from each other while placing the concrete is called ??

a. bulking
b. shrinkage
c. compaction
d. segregation

The relation between modulus of rupturefcr and characteristic strength of concrete fck is given by ?? Where fcr and fck are in N/mm2′

a. fcr=1.2Vf7
b. fcr=0.7Vf7
c. fcr=0.57f7
d. fcr=0.35Vf7

The approximate value of shrinkage strain in concrete is ??

a. 0.03
b. 0.00003
c. 0.0003
d. 0.003

The approximate value of the ratio between direct tensile strength and flexural strength is ??

a. 1.0
b. 0.75
c. 0.5
d. 0.33

Workability of concrete is directly proportional to ??

b. time of transit
c. aggregate cement ratio
d. all of above

Air entrainment in the concrete increases ??

a. the unit weight
b. the effects of temperature variations
c. strength
d. workability

The relation between modulus of rupture fcr, splitting strength fcs and direct tensile strength fcl is given by ??

a. fc5>fcr>fC
b. fcr<fcs
c. fcr>fcs>fc
d. tcr – rcs = tct

Workability of concrete is inversely proportional to ??

a. size of aggregate
b. the air in the mix
c. ‘water-cement ratio
d. time of transit

Strength of concrete increases with ??

a. decrease in size of aggregate
b. decrease in curing time
c. increase in fineness of cement
d. increase in water-cement ratio

### Part 1 Design Structure MCQs

The property of fresh concrete, in which the water in the mix tends to rise to the surface while placing and compacting, is called ??

a. creep
b. bulking
c. bleeding
d. segregation

As compared to ordinary portland cement, use of pozzolanic cement ??

a. increases strength
b. increases shrinkage
c. increases bleeding
d. reduces workability

To determine the modulus of rupture, the size of the test specimen used is ??

a. 100 x100 x500 mm
b. 150 x150 x700 mm
c. 100 x100 x700 mm
d. 150 x150 x500 mm

According to IS: 456 -1978, the modulus of elasticity of concrete Ec (in N/mm2) can be taken as ??

a. Ec = where fck N/mm2 = 700 is the characteristic strength in
b. Ec = = 5700fck
c. Ec = = 570
d. Ec = = 5700

The percentage of voids in cement is approximately ??

a. 80%
b. 60%
c. 40%
d. 25%

The most commonly used admixture which prolongs the setting and hardening time is ??

a. sodium silicate
b. calcium chloride
c. gypsum
d. all of the above

Modulus of rupture of concrete is a measure ??

a. split tensile strength
b. compressive strength
c. direct tensile strength
d. flexural tensile strength

The strength of concrete after one year as compared to 28 days strength is about ??

a. 25 to 50% more
b. 20 to 25% more
c. 15 to 20% more
d. 10 to 15% more

In order to obtain the best workability of concrete, the preferred shape of aggregate is ??

a. angular
b. elongated
c. rounded
d. all of the above

Admixtures that cause early setting and hardening of concrete are called ??

a. air-entraining agents
b. retarders
c. accelerators

### Design Concrete Structures Part 1

If the permissible stress in steel in tension is 140 N/mm2, then the depth of neutral axis for a singly reinforced rectangular balanced section will be ??

a. dependent on the grade of concrete also
b. 0.45 d
c. 0.40 d
d. 0.35 d

As compared to ordinary portland cement, high alumina cement has ??

a. lower initial and final setting times
b. higher initial and final setting times
c. lower initial setting time but higher final setting time
d. higher initial setting time but lower final setting time

The minimum grade of concrete to be used in reinforced concrete as per IS:456-1978 is ??

a. M25
b. M 10
c. M20
d. M15

Bulking of sand is maximum if the moisture content is about ??

a. 10%
b. 6%
c. 4%
d. 2 %

The maximum quantity of water needed per 50 kg of cement for M 15 grade of concrete is ??

a. 34 liters
b. 32 liters
c. 30 liters
d. 28 liters

1% of voids in a concrete mix would reduce its strength by about ??

a. 20%
b. 15%
c. 10 %
d. 5%

For concreting of heavily reinforced sections without vibration, the workability of concrete expressed as compacting factor should be ??

a. above 0.92
b. 0.85 – 0.92
c. 0.80-0.85
d. 0.75-0.80

Finer grinding of cement ??

a. affects only the ultimate strength
b. affects only the early development of strength
c. both (A. and (B)
d. does not affect the strength

In case of hand mixing of concrete, the extra cement to be added is ??

a. 20%
b. 15%
c. 10%
d. 5%

Poisson’s ratio for concrete ??

a. increases with richer mixes
b. decreases with richer mixes
c. remain constant
d. none of the above

#### Design Concrete Structures Part 1

The individual variation between test strength of sample should not be more than ??

a. ±20% of average
b. ± 15% of average
c. ± 10% of average
d. ±5% of average

The factor of safety for ??

a. steel is lower than that for concrete
b. steel is higher than that for concrete
c. steel and concrete are same
d. none of the above

For walls, columns, and vertical faces of all structural members, the formwork is generally removed after ??

a. 14 days
b. 7 days
c. 3 days
d. 24 to 48 hours

The fineness modulus of fine aggregate is in the range of ??

a. 6.0 to 8.5
b. 5.0 to 7.0
c. 3.5 to 5.0
d. 2.0 to 3.5

The compressive strength of 100 mm cube as compared to 150 mm cube is always ??

a. more
b. equal
c. less
d. none of the above

One of the criteria for the effective width of flange of T-beam is bf =—+ BW +6Df 6 In the above formula, l0 signifies ??

a. distance between points of zero moments in the beam
b. distance between points of maximum moments in the beam
c. the effective span of T-beam
d. clear span of the T-beam

If a beam fails in bond, then its bond strength can be increased most economically by ??

a. providing vertical stirrups
b. using thicker bars but less in number
c. using thinner bars but more in number
d. increasing the depth of the beam

For a continuous slab of 3 m x 3.5 m size, the minimum overall depth of slab to satisfy vertical deflection limits is ??

a. 120 mm
b. 100 mm
c. 75 mm
d. 50 mm

If the depth of the actual neutral axis in a beam is more than the depth of the critical neutral axis, then the beam is called ??

a. over-reinforced beam
b. under-reinforced beam
c. balanced beam
d. none of the above

According to IS: 456-1978, the flexural strength of concrete is ??

a. inversely proportional to the square root of compressive strength
b. directly proportional to the square root of compressive strength
c. inversely proportional to compressive strength
d. directly proportional to compressive strength

##### Design Concrete Structures Part 1

For a cantilever of effective depth of 0.5m, the maximum span to satisfy vertical deflection limit is ??

a. 5 m
b. 4.5 m
c. 4 m
d. 3.5 m

According to IS: 456-1978, the maximum reinforcement in a column is ??

a. 8 %
b. 6 %
c. 4%
d. 2 %

Diagonal tension in a beam ??

a. increases below the neutral axis and decreases above the neutral axis
b. decreases below the neutral axis and increases above the neutral axis
c. is maximum at neutral axis
d. remains same

Which of the following statements is incorrect ??

a. The number of longitudinal bars provided in a circular column should not be less than four
b. Reinforcing bars in a column should not be less than 12 mm in diameter
c. The spacing of longitudinal bars measured along the periphery of a column should not exceed 300 mm
d. The minimum cross-sectional area of longitudinal reinforcement in a column is 0.8%

According to IS: 456-1978, the column or the strut is the member whose effective length is greater than ??

a. 4 times the least lateral dimension
b. 3 times the least lateral dimension
c. 2 times the least lateral dimension
d. the least lateral dimension

The minimum pitch of transverse reinforcement in a column is ??

a. lesser of the above three values
b. forty-eight times the diameter of transverse reinforcement
c. sixteen times the smallest diameter of longitudinal reinforcement bar to be tied
d. the least lateral dimension of the member

For a simply supported beam of span 15m, the minimum effective depth to satisfy the vertical deflection limits should be ??

a. 750 mm
b. 900 mm
c. 600 mm
d. more than 1 m

A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D. is less than ??

a. 3.0
b. 2.5
c. 2.0
d. 1.5

According to IS 456- 1978, the minimum slenderness ratio for a short column is ??

a. more than 24
b. between 18 and 24
c. less than 18
d. less than 12

Minimum thickness of load-bearing RCC wall should be ??

a. 200 mm
b. 150 mm
c. 100 mm
d. 50 mm

The minimum cover in a slab should neither be less than the diameter of the bar nor less than ??

a. 13 mm
b. 25 mm
c. 15 mm
d. 10 mm

###### Design Concrete Structures Part 1

In reinforced concrete footing on soil, the minimum thickness at the edge should not be less than ??

a. 250 mm
b. 200 mm
c. 150 mm
d. 100 mm

The ratio of the diameter of reinforcing bars and the slab thickness is ??

a. 1/8
b. 1/6
c. 1/5
d. 1/4

The slab is designed as one way if the ratio of long span to short span is ??

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

The percentage of reinforcement in the case of slabs, when high strength deformed bars are used is not less than ??

a. 1.00
b. 0.30
c. 0.12
d. 0.15

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

a. 30
b. 20
c. 10
d. 0

For a longitudinal reinforcing bar in a column, the minimum cover shall neither be less than the diameter of bar nor less than ??

a. 40 mm
b. 30 mm
c. 25 mm
d. 15 mm

Critical section for shear in case of flat slabs is at a distance of ??

a. at the periphery of column
b. at the drop panel of slab
c. d/2 from the periphery of column/capital/ drop panel
d. the effective depth of slab from the periphery of column/drop panel

Lap length in compression shall not be less than ??
where (j) is the diameter of the bar

a. 30 (j)
b. 24 (j)
c. 20
d. 15 4>

The limits of percentage p of the longitudinal reinforcement in a column are given by ??

a. 0.8% to 8%
b. 0.8% to 6%
c. 0.8% to 4%
d. 0.15% to 2%

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