Quiz: Civil Engineering 27 june 2020

Quiz: Civil Engineering
Exam: UPPSC-AE
Topic: Miscellaneous

Each question carries 1 mark
Negative marking: 1/3 mark
Time: 10 Minutes

Q1. Which of the following relation is/are used in deriving the relation between the flow rate and the pressure difference between the straight section and the throat of a venturi-meter that has no losses?
(a) ideal gas law
(b) Bernoulli and continuity equation
(c) Relation between friction factor and Reynolds number and Bernoulli equation
(d) Bernoulli equation

Q2. Which of the following are the common problems associated with the operation of rapid sand-filter?
1. Air binding
2. Cracking of sand beds
3. Bumping of filter beds
4. Mud balls
Select the correct answer using the codes given below:
(a) 1 and 2
(b) 2 and 3
(c) 2, 3 and 4
(d) 1, 2, 3 and 4

Q3. The lost time due to starting delay on a traffic signal is notes to be 3s, the actual green time is 25s and yellow time is 3s. How much is the effective green time?
(a) 31s
(b) 28s
(c) 25s
(d) 22s

Q4. A given piece of land is said to be waterlogged when:
(a) there is a water flowing on the land surface
(b) Capillary fringe reaches the root zone of plants
(c) Gravity drainage has ceased
(d) The permanent wilting point is reached

Q5. Left swing is not much favoured in theodolite survey, because
(a) Most of surveyors are accustomed to right hand
(b) it is inconvenient to turn the telescope anti-clockwise
(c) the readings increase clockwise
(d) vertical scale comes to an inconvenient position to be read

Q6. The grade of concrete M-15 means that compressive strength of a 15 cm cube after 28 days, is ………….
(a) 100 kg/cm²
(b) 150 kg/cm²
(c) 200 kg/cm²
(d) 250 kg/cm²

Q7. A clay has unconfined compressive strength of 200 kN/sq m in undisturbed state. The clay was then remolded and the unconfined compressive strength was found to be 60 kN/sq m. the sensitivity of this clay is:
(a) 0.30
(b) 3.33
(c) 2.33
(d) 1.68

Q8. If nominal shear stress (τ_v) exceeds the design shear strength of concrete (τ_C), the shear reinforcement as per IS – 456 will be provided for shear equal to –
(a) τ_C
(b) τ_v
(c) τ_v – τ_C
(d) τ_v + τ_C

Q9. The stress level, below which a material has a high probability of not failing under reversal of stress, is known as
(a) elastic limit
(b) endurance limit
(c) proportional limit
(d) tolerance limit

Q10. The angle of the failure plane with the major principal plane is given by
(a) 45° + ϕ’
(b) 45° +(ϕ’)/2
(c) 45° – (ϕ’)/2
(d) 45° – ϕ’

SOLUTION

S1. Ans.(b)
Sol. for derive the relation between the flow rate and the pressure difference between the throat and straight section of a venturi meter we need continuity equation and Bernoulli’s equation both.

S2. Ans.(d)
Sol. Common problems associated with filtration of waste water are:
(i) Air binding
(ii) Turbidity breaks through cracking of sand bed
(iii) Mudball formation
(iv) Build-up of emulsified grease
(v) Loss of filter medium due to backwashing
(vi) Gravel moulding or bumping of filter beds.

S3. Ans.(c)
Sol. Effective green time = Actual green time + Yellow time – lost time
= 25 + 3 – 3 = 25 seconds

S4. Ans.(b)
Sol. A given piece of land is said to be water logged when
Capillary fringe reaches the root zone of plants.
Due to rise of water table up to ground level.
Area is full of salinity.

S5. Ans.(c)
Sol. when telescope is rotated about vertical axis called swinging of theodolite. When theodolite moved rightward it’s known as right swing & when left word it’s known as left swing. Left word swing of theodolite is neglected because in left swing reading value increase.

S6. Ans.(b)
Sol. The compressive strength of M15 grade of concrete is 150 kg /cm² or 15 N/mm² of 15 cm. cube at 28 days.

S7. Ans.(b)
Sol. Sensitivity=(Unconfined compressive strength)undisturbed/(Unconfined compressive strength)remoulded
Sensitivity=200/60=3.33

S8. Ans.(c)
Sol. if nominal shear stress (τ_v ) exceceds the design shear strength of concrete (τ_c ) than shear reinforcement will be provided to resist (τ_v-τ_c )
Some important point in shear reinforcement
→ if τ_V> τ_cmax then redesign the section
→if τ_V<τ_c/2 then no shear reinforcement provided
→ if τ_V < τ_c minimum shear reinforcement provided
→ if τ_V > τ_c then design shear reinforcement to resist (τ_V-τ_c )

S9. Ans.(b)
Sol. The stress which can be withstand for some infinite number of cycles without failure is called endurance limit. Endurance limit magnitude less then yield strength.

S10. Ans.(b)
Sol. Angle of the failure plane with the major principal plane is
[45+ϕ/2]

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