Quiz: Civil Engineering 9 Dec 2020

Quiz: Civil Engineering
Topic: Miscellaneous

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

Q1. If the fore bearing of the line AB is 119°48’ then back baring is:
(a) 299° 48’
(b) 209°48’
(c) 119°48’
(d) 319°48’

Q2. Calculate detention time of the tank whose breadth is 2 m, length is 4 m and depth is 2.5m. the rate of flow is 4 x 10³ liters per hour
(a) 5 hours
(b) 4 hours
(c) 5.5 hours
(d) 2.5 hours

Q3. 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

Q4. A soil has a discharge velocity of 6 × 10^(-7) m/s and void ratio of 0.5. What is its seepage velocity?
(a) 3 × 10^(-7) m/s
(b) 6 × 10^(-7) m/s
(c) 12 × 10^(-7) m/s
(d) 18 × 10^(-7) m/s

Q5. The hydraulic head that would produce a quick sand condition in a sand stratum of thickness 1.8m, specific gravity 2.65 and void ratio 0.65 is equal to:
(a) 1.0 meter
(b) 1.2 meter
(c) 1.6 meter
(d) 1.8 meter

Q6. What will be the shift of the transition curve, if the length of transition curve is 80 m and radius of the curve is 320 m?

Q7. Lacey’s silt factor for medium silt whose average gain size is 0.25 mm, is likely to be:
(a) 0.66
(b) 0.77
(c) 0.88
(d) 0.99

Q8. The operation of converting limestone into quicklime by heating it to temperature upto 900°C and releasing carbon dioxide is known as:
(a) Charging
(b) Calcination
(c) Drawing
(d) Hydrating

Q9. The maximum dimension of a core section for a rectangular cross-section under eccentric loading on a column (b×d) is
(a) b/6
(b) d/6
(c) d/8
(d) b/3 and d/3

Q10. Newton’s law of viscosity is a relationship between-
(a) Rate of shear strain & temperature
(b) Shear stress & rate of shear strain
(c) Pressure, velocity & temperature
(d) Shear stress & velocity


S1. Ans.(a)
Sol. fore bearing of line ‘AB’ = 119°48’
Fore baring is less than 180° so we calculate back bearing by adding 180°. If fore bearing greater than 180° than we subtract 180° from it.
Back bearing of line AB = 180°+〖119°48〗^’=〖299°48〗^’

S2. Ans.(a)
Sol. Given,
Length (L) = 4m.
Breadth (B) = 2 m.
Depth (D) = 2.5 m.
Discharge (Q) = 4 × 10³ l/hour
Detention time of tank (t_d) =?
t_d = (Volume of tank (V))/(Discharge (Q) )
= (4×2×2.5 (m^3 ))/(4×10^3×10^(-3) (m^3 \/hour) )
= 5 hours.

S3. 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 )

S4. Ans.(d)
Sol. discharge velocity (V) = 6 × 10^(-7) m/s
Void ratio (e) = 0.5
Porosity (n) = e/(1+e)
= 0.5/(1+0.5)
= 0.5/1.5
Seepage velocity (V_s ) = V/n
V_s=18.18× 10^(-7) m/sec

S5. Ans.(d)
Sol. thickness (t) = 1.8 m
G = 2.65
Void ratio (e) = 0.65
For quick sand condition –
Critical hydraulic gradient (i_c ) = (G-1)/(1+e)
▭(∆h=1.8 meter)

S6. Ans.(b)
Sol. Given, length of transition curve (L) = 80 m.
Radius of the curve (R) = 320 m.
Shift (S) = L^2/24R = (〖(80)〗^2 )/(24×320) = 0.83 m.

S7. Ans.(c)
Sol. Given, dmm = 0.25 mm
Lacey’s silt factor (f) = 1.76 √dmm
= 1.76 √0.25
= 0.88

S8. Ans.(b)
Sol. Calcination is a process of heating the limestone up to redness.
CaCO_3 ——Calcination——- CaO+CO_2

S9. Ans.(d)
Sol. The maximum dimension of a core section for a rectangular cross-section under eccentric loading on a column (b × d) is b/3 or d/3. The shape of kern or core for rectangular and I – section is Rhombus.

S10. Ans.(b)
Sol. Newton’s law states that the shear stress is directly proportional to the rate of shear strain for Newtonian fluid.
τ α dv/dy

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