hoskerelab/PE_Civil_Bench huggingface dataset:
Subdiscipline: structural

\textbf{Question 57:} The enclosed office building 20 ft high is located in a region with a basic wind speed of 120 mph. The building is located on flat terrain with possible exposure of C. The uniformly distributed pressure (psf) due to the wind on the wall of the building is most nearly:

\textbf{A.} 30.2

\textbf{B.} 28.2

\textbf{C.} 24.6

\textbf{D.} 26.6

Answer: D
Subdiscipline: structural

\textbf{Question 58:} A 12-foot-long simply supported beam is subjected to a uniformly varying load that starts at 300 lb/ft at point A and increases linearly to 350 lb/ft at point B. The vertical reaction in lb at the right support, B of the following beam is most nearly:

\textbf{A.} 2,000

\textbf{B.} 3,000

\textbf{C.} 2,200

\textbf{D.} 2,800

Answer: A
Subdiscipline: structural

\textbf{Question 59:} A statically determinate three-hinged arch is subjected to a 200 lb point load at point C. Point C is located 5 meters above the line connecting supports A and B. Additionally, point C is positioned 3 meters to the right of support B and 4 meters to the left of support A. What is the vertical reaction at the right support (A)?

\textbf{A.} 76

\textbf{B.} 86

\textbf{C.} 98

\textbf{D.} 114.3

Answer: B
Subdiscipline: structural

\textbf{Question 60:} A window consists of a rectangle with a width of 24 inches and a height of 14 inches. A semicircle, with a diameter equal to the width of the rectangle, is mounted on top of the rectangle. The centroid of this composite shape (rectangle and semicircle) relative to the bottom-left corner of the rectangle is most nearly:

\textbf{A.} (12, 14.4) inch

\textbf{B.} (12, 19.1) inch

\textbf{C.} (12, 11.9) inch

\textbf{D.} (12, 18) inch

Answer: C
Subdiscipline: structural

\textbf{Question 61:} What modulus of elasticity is predicted by ACI 318 for normal weight concrete with a compressive strength of 3000 lbf/in\(^2\)?

\textbf{Options:}

\begin{itemize} \item (A) \( 0.26 \times 10^6 \, \text{psi} \) \item (B) \( 1.9 \times 10^6 \, \text{psi} \) \item (C) \( 2.8 \times 10^6 \, \text{psi} \) \item (D) \( 3.2 \times 10^6 \, \text{psi} \) \end{itemize}

Answer: D
Subdiscipline: structural

\textbf{Question 62:} A metal with a high hardness value will have:

\textbf{A.} High weldability

\textbf{B.} High tensile strength

\textbf{C.} High thermal conductivity

\textbf{D.} High stiffness

Answer: B
Subdiscipline: geotechnical

\textbf{Question 63:} A chunk of moist soil weighs 49 lb with a volume of 0.46 ft\(^3\). After oven drying, the weight decreases to 38 lb. The specific gravity and the void ratio of the soil are 2.64 and 1.1, respectively. The saturated unit weight of the soil is most nearly:

\textbf{A.} 91 pcf

\textbf{B.} 101 pcf

\textbf{C.} 106 pcf

\textbf{D.} 111 pcf

Answer: D
Subdiscipline: geotechnical

\textbf{Question 64:} Two identical building footings with the same load but constructed in two different soil types (clay and sand). Which of the following statements is most correct?

\textbf{A.} The long-term settlement in clay is less than that of sand

\textbf{B.} The long-term settlement in clay is equal to that of sand

\textbf{C.} The long-term settlement in clay is more than that of sand

\textbf{D.} The long-term settlement is not a concern in geotechnical engineering

Answer: C
Subdiscipline: geotechnical

\textbf{Question 65:} A soil can be compacted to the maximum dry density of 130 pcf and the minimum dry density of 90 pcf. After field testing, it was found that the compacted dry density of the soil is 110 pcf. The relative density of the in-situ soil is most nearly:

\textbf{A.} 41\%

\textbf{B.} 46\%

\textbf{C.} 49\%

\textbf{D.} 59\%

Answer: D
Subdiscipline: geotechnical

\textbf{Question 66:} Water flows through a soil whose cross-sectional area is 0.05 m\(^2\). The hydraulic gradient is 0.12 and the coefficient of permeability is \(5 \times 10^{-4}\) m/sec. If water flows for 2 minutes, the total flow is most nearly:

\textbf{A.} \(3.6 \times 10^{-4}\) m\(^3\)

\textbf{B.} \(6.2 \times 10^{-3}\) m\(^3\)

\textbf{C.} \(4.5 \times 10^{-3}\) m\(^3\)

\textbf{D.} None of the above

Answer: A
Subdiscipline: geotechnical

\textbf{Question 67:} The seepage-exit gradient of a saturated soil with a unit weight of 130 pcf is 0.3. The factor of safety against liquefaction is most nearly:

\textbf{A.} 3.6

\textbf{B.} 10

\textbf{C.} 6

\textbf{D.} None of the above

Answer: A
Subdiscipline: geotechnical

\textbf{Question 68:} A soil profile consists of three layers: silt, sand, and clay, with thickness of 6 ft, 5 ft, and 8 ft respectively. The silt layer is on top, sand is on between and clay in on bottom. The unit weights are 110 pcf for the silt, 120 pcf for the sand, and 130 pcf for the clay. The water table is located just below the silt layer, at the start of the sand layer. Given the depths and unit weights of the layers, the task is to calculate the consolidation settlement in the clay layer due to a new construction?

The clay layer has the following properties:
The clay layer has a pre-consolidation pressure of 1,300 psf, a liquid limit of 40\%, and a coefficient of consolidation = \(3 \times 10^{-3}\) in\(^2\)/min. The increase in pressure in the clay layer due to the new construction = 500 psf. The void ratio of clay = 0.9

\textbf{A.} 1.72 in

\textbf{B.} 0.26 in

\textbf{C.} 2.21 in

\textbf{D.} None of the above

Answer: A
Subdiscipline: geotechnical

\textbf{Question 69:} A sand sample was tested in a triaxial device. At the beginning of the test, a confining pressure of 50 psi was applied, and deviatoric pressure was started. The sample failed when the applied external pressure reached 320 psi. The angle of internal friction of the sand is most nearly:

\textbf{A.} 32°

\textbf{B.} 37°

\textbf{C.} 43°

\textbf{D.} 47°

Answer: D
Subdiscipline: geotechnical

\textbf{Question 70:} A soil profile consists of three layers: silt, sand, and clay, with respective depths of 6 ft, 5 ft, and 8 ft. The wet unit weights are 110 pcf for the silt, 120 pcf for the sand, and 130 pcf for the clay. The water table is located just below the silt layer, at the start of the sand layer. Below the clay layer, impervious rock is present. The depths of the layers and their wet-unit weights are also shown. Most nearly how much time will it take to settle 99\% of the consolidation settlement in the clay layer due to the new construction?

The clay layer has the following properties:
The clay layer has a pre-consolidation pressure of 1,300 psf, a liquid limit of 40\%, and a coefficient of consolidation = \(3 \times 10^{-3}\) in\(^2\)/min. The increase in pressure in the clay layer due to the new construction = 500 psf. The void ratio of clay = 0.9

\textbf{A.} 10.4 years

\textbf{B.} 4.23 years

\textbf{C.} 0.37 years

\textbf{D.} 32 months

Answer: A
Subdiscipline: geotechnical

\textbf{Question 71:} In a shear test on sand, the following results were obtained: \\
Area of sample = 4.0 in\(^2\) \\
Normal load at failure = 20 lb \\
Shear stress at failure = 5 psi \\
The sand's angle of internal friction is most nearly:

\textbf{A.} 22°

\textbf{B.} 38°

\textbf{C.} 32°

\textbf{D.} 45°

Answer: D
Subdiscipline: construction

\textbf{Question 72:} A back-loader construction equipment has a useful life of 10 years. It has an initial cost of \$150,000, a salvage value of \$5,000, and annual maintenance of \$1,000. The interest rate is 8\%. The present worth of the costs of the back-loader is most nearly:

\textbf{A.} \$158,400

\textbf{B.} \$92,400

\textbf{C.} \$132,400

\textbf{D.} \$154,400

Answer: D
Subdiscipline: geotechnical

\textbf{Question 73:} A soil mass has a slope inclined at 60 degrees to the horizontal, and the slip surface starts from the toe of the slope, making an angle of 35 degrees with the horizontal. Given the following soil properties:

\begin{itemize}
\item Unit weight of the soil: \( \gamma = 130 \, \text{pcf} \)
\item Cohesion: \( c = 110 \, \text{psf} \)
\item Angle of internal friction: \( \phi = 30^\circ \)
\end{itemize}

The weight of the soil above the slip surface is most nearly:

\textbf{A.} 14 kip/ft

\textbf{B.} 16 kip/ft

\textbf{C.} 22 kip/ft

\textbf{D.} 28 kip/ft

Answer: C
Subdiscipline: water resources

\textbf{Question 74:} Which of the following statements is true for viscosity?

\textbf{A.} It is the ratio of inertial to viscous force

\textbf{B.} It is usually low when turbulent forces predominate

\textbf{C.} It always has a large effect on the value of the friction force

\textbf{D.} It is the ratio of the shear stress to the rate of shear deformation

Answer: D
Subdiscipline: water resources

\textbf{Question 75:} A reservoir with a water surface level at an elevation of 200 m drains through a 1 m diameter pipe with the outlet at an elevation of 180 m. The pipe outlet discharges to atmospheric pressure. The total head losses in the pipe and fittings are 18 m. Assume steady incompressible flow.

The flow rate out of the pipe outlet is most nearly?

\textbf{A.} 4.9 m\(^3\)/s

\textbf{B.} 6.3 m\(^3\)/s

\textbf{C.} 31 m\(^3\)/s

\textbf{D.} 39 m\(^3\)/s

Answer: A
Subdiscipline: water resources

\textbf{Question 76:} Assuming that Bernoulli's equation applies ignoring head losses to the pipe flow shown in the figure, which of the following statements is most correct? The flow is flowing from 1 to 2 (smaller to larger diameter conduit).

\textbf{A.} Pressure head increases from 2 to 1

\textbf{B.} Pressure heads are equal both at 1 and 2

\textbf{C.} Pressure head increases from 1 to 2

\textbf{D.} None of the above

Answer: C
Subdiscipline: water resources

\textbf{Question 77:} An incompressible fluid is flowing through a 2-inch diameter pipe with a velocity of 10 m/s. If the pipe is connected to a 4-inch diameter pipe, the decrease in velocity is most nearly:

\textbf{A.} 2.5 m/s

\textbf{B.} 5 m/s

\textbf{C.} 7.5 m/s

\textbf{D.} None of the above

Answer: C
Subdiscipline: water resources

\textbf{Question 78:} Assume fully turbulent flow in a 2,000-ft section of a 2.5-ft diameter pipe. The Darcy-Weisbach friction factor is 0.015. There is a 4-ft drop in the energy grade line over the section. The flow rate (cfs) is most nearly:

Answer: 23
Subdiscipline: water resources

\textbf{Question 79:} A fluid with an absolute dynamic viscosity of 1.5 kg/(m \cdot s), and specific gravity of 1.4, has a kinematic viscosity (m\(^2\)/s) of most nearly:

\textbf{A.} \(1.07 \times 10^{-3}\) m\(^2\)/s

\textbf{B.} \(1.07 \times 10^3\) m\(^2\)/s

\textbf{C.} \(7.07 \times 10^{-3}\) m\(^2\)/s

\textbf{D.}\(1.07 \times 10^{-2}\) m\(^2\)/s

\

Answer: A
Subdiscipline: water resources

\textbf{Question 80:} A flow of 15.5 cfs enters the pipe system at A as shown, and exists at B and C. Pipe data are given in the following table:

\begin{tabular}{|c|c|c|c|c|} \hline \textbf{Pipe} & \textbf{Length (ft)} & \textbf{f} & \textbf{Diameter (in)} & \textbf{Velocity (fps)} \\ \hline AB & 200 & 0.03 & 24 & 2.0 \\ AC & 200 & 0.03 & 36 & 1.2 \\ CB & 200 & 0.03 & 48 & \\ \hline \end{tabular}

The head loss in pipe CB in feet is most nearly:

\textbf{A.} 0.14

\textbf{B.} 0.21

\textbf{C.} 0.26

\textbf{D.} 0.31

Answer: A
Subdiscipline: water resources

\textbf{Question 81:} Archimedes' principle states that:

\textbf{A.} The sum of pressure, velocity, and elevation heads is constant

\textbf{B.} Flow passing two points in a stream is equal at each point

\textbf{C.} The buoyant force on a body is equal to the volume displaced by the body

\textbf{D.} A floating body displaces a weight of fluid equal to its weight

Answer: D
Subdiscipline: water resources

\textbf{Question 82:} The rectangular homogeneous gate shown below is 6.0 m in height and has frictionless hinges at the bottom. The fluid on the right side of the gate has a density of 1,200 kg/m³. If the width of the body is 1.0 m, what is the magnitude of the force, F (kN) required to keep the gate closed?

\textbf{A.} 91

\textbf{B.} 71

\textbf{C.} 81

\textbf{D.} 61

Answer: B
Subdiscipline: water resources

\textbf{Question 83:} The pressure in a water main at ground level is 100 psi. An engineer is designing an eight-story building with 12-ft height each story. If the friction of water pipe can be neglected, what will be the pressure on the eighth floor?

\textbf{A.} 41.6 psi

\textbf{B.} 5,990 psi

\textbf{C.} 74.2 psi

\textbf{D.} 58.4 psi

Answer: D
Subdiscipline: water resources

\textbf{Question 84:} The nominal value of the head loss in a well-streamlined gradual contraction with a flow velocity of 5 ft/sec is most nearly:

\textbf{A.} 0.05 ft

\textbf{B.} 0.015 ft

\textbf{C.} 0.1 ft

\textbf{D.} None of the above

Answer: B
Subdiscipline: structural

\textbf{Question 85:} What is the moment capacity (\( \phi M_n \)) of the following beam? \( f_c = 0.9 \), \( f_y = 60 \, \text{ksi} \). The beam has total depth of 21 inch and width of 12 inch. The beam has 3 number 8 bar. The effective depth is 18 inch.

\textbf{A.} 173 kip⋅ft

\textbf{B.} 123 kip⋅ft

\textbf{C.} 321 kip⋅ft

\textbf{D.} 213 kip⋅ft

Answer: A
Subdiscipline: structural

\textbf{Question 86:} A tied column is to support a dead load of 180 kip and a live load of 220 kip. For 4\% steel reinforcement, what would be the required gross area of the column? \( f'_c = 4 \, \text{ksi}, f_y = 60 \, \text{ksi} \).

\textbf{A.} 62 in²

\textbf{B.} 193 in²

\textbf{C.} 78 in²

\textbf{D.} 213 in²

Answer: B
Subdiscipline: structural

\textbf{Question 87:} A factored load of 300 kip is applied on a 20-in² tied column with 8-in. eccentricity. What is the required steel amount for this column? \( f'_c = 4 \text{ksi}\) \( f_y = 60 \text{ksi} \), \(\phi = 0.65\). The cover is taken as 2 inch.

\textbf{A.} 1.8 in²

\textbf{B.} 4 in²

\textbf{C.} 8.6 in²

\textbf{D.} 10.9 in²

Answer: B
Subdiscipline: structural

\textbf{Question 88:} What is the design concrete shear strength of plain concrete of the following reinforced-concrete section? \( f'_c = 4,000 \text{psi} \). The effective depth of beam is 12 inch and a cover of 3 inch. The width of beam is 10 inch.

\textbf{A.} 14 kip

\textbf{B.} 19 kip

\textbf{C.} 21 kip

\textbf{D.} 11.4 kip

Answer: D
Subdiscipline: structural

\textbf{Question 89:} The following beam uses \( f_y = 60 \, \text{ksi} \) and \( f_c' = 4,000 \, \text{psi} \). The maximum factored shear force experienced by the beam is 20,000 lb. If a #3 U stirrup is used, what is the maximum spacing permitted? The beam has effective depth of 20 inch, cover of 3 inch and width of 12 inch.

\textbf{A.} 8 in.

\textbf{B.} 18 in.

\textbf{C.} 10 in.

\textbf{D.} 24 in.

Answer: C
Subdiscipline: structural

\textbf{Question 90:} A reinforced-concrete beam is subjected to a factored moment of 500 kip⋅ft. The beam is reinforced with 6 #10 bars in two rows, 3-in. center, as shown below. The section uses 4-ksi concrete and 60-ksi reinforcement. The section also has a 3-in. cover from the center of the bottom row of steel. Assuming a strength reduction factor of 0.9, what is the width of the section?

The beam has a total depth of 25.5 inch.

\textbf{A.} 9

\textbf{B.} 11

\textbf{C.} 13

\textbf{D.} 15

Answer: B
Subdiscipline: structural

\textbf{Question 91:} The elastic modulus of concrete with \( J_e' = 3 \, \text{ksi} \) and a unit weight of 145 pcf is most nearly:

\textbf{A.} 3,155 ksi

\textbf{B.} 3,834 ksi

\textbf{C.} 3,484 ksi

\textbf{D.} 3,562 ksi

Answer: A
Subdiscipline: structural

\textbf{Question 92:} For a structure, the nominal floor live load recommended by the ASCE 7 is 120 psf. The minimum load after applying the live load reduction factor is most nearly:

\textbf{A.} 40 psf

\textbf{B.} 48 psf

\textbf{C.} 80 psf

\textbf{D.} 100 psf

Answer: B
Subdiscipline: structural

\textbf{Question 93:} If the dead load shear force in the beam is 5 kips and the live load shear force in the beam is 15 kips, then the minimum amount of shear reinforcement needed for a center to center stirrup spacing of  12 inch based on ACI strength design is most nearly?

\textbf{A.} 0.001 in²

\textbf{B.} 0.0012 in²

\textbf{C.} 0.135 in²

\textbf{D.} 0.18 in²

Answer: D
Subdiscipline: structural

\textbf{Question 94:} The critical stress of a steel W12x40 section is 40 ksi. The design compressive strength of that column is most nearly:

\textbf{A.} 156 kip

\textbf{B.} 166 kip

\textbf{C.} 421 kip

\textbf{D.} 192 kip

Answer: C
Subdiscipline: structural

\textbf{Question 95:} For a sideway inhibited frame, what is most nearly the value of 'K' if \( G_a = 10 \), \( G_B = 0.5 \)?

\textbf{A.} 0.82

\textbf{B.} 0.65

\textbf{C.} 0.75

\textbf{D.} 0.85

Answer: A
Subdiscipline: structural

\textbf{Question 96:} A steel W21x50 section has a laterally unsupported length of 8 ft. The design moment capacity of the section in kip⋅ft is most nearly:

\textbf{A.} 253

\textbf{B.} 351

\textbf{C.} 459

\textbf{D.} 413

Answer: B
Subdiscipline: transportation

\textbf{Question 97:} A freeway has a traffic flow of 2,000 veh/hr and an average vehicle speed of 60 mph. The time spacing between vehicles is most nearly:

\textbf{A.} 2.4 sec/veh

\textbf{B.} 1.8 sec/veh

\textbf{C.} 1.2 sec/veh

\textbf{D.} 0.6 sec/veh

Answer: B
Subdiscipline: surveying

\textbf{Question 98:} A horizontal curve has the following data: \\
I = 36°50' \\
R = 750 ft \\
Station of PI = 8+00 \\
The station of the PT is most nearly:

\textbf{A.} 9+52

\textbf{B.} 9+77

\textbf{C.} 10+05

\textbf{D.} 10+32

Answer: D
Subdiscipline: transportation

\textbf{Question 99:} What is the advantage of using a parabola in the vertical design of highways and railroads?

\textbf{A.} Easy construction

\textbf{B.} Easy calculation

\textbf{C.} Looks beautiful

\textbf{D.} Because parabolas provide a constant rate of change of grade

Answer: D
Subdiscipline: transportation

\textbf{Question 100:} A common full-size car has 2 single axles with a 2-kip load on each. Considering pavement damage, how many full-size cars are equivalent to a 48-kip tandem axle?

\textbf{A.} 32

\textbf{B.} 21,000

\textbf{C.} 13,000

\textbf{D.} 11,600

Answer: D
Subdiscipline: transportation

\textbf{Question 101:} In a region, the average 7-day maximum pavement design temperature is 60 °C, and the minimum pavement design temperature is -15 °C. The recommended asphalt binder for this region is:

\textbf{A.} PG 52-16

\textbf{B.} PG 50-10

\textbf{C.} PG 64-16

\textbf{D.} All of the above

Answer: C
Subdiscipline: transportation

\textbf{Question 102:} In a 3\% downhill grade, the maximum velocity may be expected to be 55 mph. What should be the yellow interval length if an average deceleration rate of 5 ft/sec² is available? The driver reaction time is 1 sec.

\textbf{A.} 4 sec

\textbf{B.} 11 sec

\textbf{C.} 8 sec

\textbf{D.} More information is needed to calculate

Answer: B
Subdiscipline: transportation

\textbf{Question 103:} The cross-sectional areas to be excavated at a proposed highway are mentioned below:

\begin{tabular}{|c|c|}
\hline
\textbf{Station} & \textbf{Area (ft²)} \\
\hline
122+00 & 2300 \\
125+00 & 2100 \\
130+00 & 2300 \\
135+00 & 2190 \\
140+00 & 2300 \\
\hline
\end{tabular}

The volume of excavation of that highway segment from 125+00 to 135+00 is most nearly:

\textbf{A.} \( 2.52 \times 10^4 \, \text{ft}^3 \)

\textbf{B.} \( 2.22 \times 10^5 \, \text{ft}^3 \)

\textbf{C.} 83,272 yd³

\textbf{D.} \( 2.25 \times 10^6 \, \text{yd}^3 \)

Answer: C
Subdiscipline: transportation

\textbf{Question 104:} A sag vertical curve has an elevation of 443.15 ft at station 7+65 and an elevation of 441.16 ft at the point of vertical intersection (PVI). For an overpass crossing the vertical curve's roadway at station 7+65, the required clearance is 15 ft 4 inch. What is most nearly the minimum elevation of the overpass?

\textbf{A.} 427.8 ft

\textbf{B.} 428 ft

\textbf{C.} 456.5 ft

\textbf{D.} 459 ft

Answer: D
Subdiscipline: math

\textbf{Question 105:} The equation \( y = a_1 + a_2 x \) is an algebraic expression for which of the following?

\textbf{A.} a cosine expansion series

\textbf{B.} projectile motion

\textbf{C.} a circle in polar form

\textbf{D.} a straight line

Answer: D
Subdiscipline: math

\textbf{Question 106:} Consider the following reaction:
\[ 2A + B \rightleftharpoons 3C + 2D \]
The chemical equilibrium constant of the above reaction is most nearly:

\textbf{A.} \( k = \frac{[C] [D]}{[A] [B]} \)

\textbf{B.} \( k = \frac{[C]^2 [D]^3}{[A]^2 [B]} \)

\textbf{C.} \( k = \frac{[A]^2 [B]}{[C]^3 [D]^2} \)

\textbf{D.} \( k = \frac{[C]^3 [D]^2}{[A]^2 [B]} \)

Answer: D
Subdiscipline: water resources

\textbf{Question 107:} The BOD of a waste sample incubated at 30 °C for 10 days was measured to be 120 mg/L. The deoxygenation rate constant (base-10, 20 °C) is 0.23 per day. The kinetic temperature correction factor is 1.047. The BOD of the sample after 20 days of incubation at 20 °C is most nearly:

\textbf{A.} 112 mg/L

\textbf{B.} 118 mg/L

\textbf{C.} 136 mg/L

\textbf{D.} 120 mg/L

Answer: D
Subdiscipline: water resources

\textbf{Question 108:} The biodegradation of benzene \( C_6H_6 \) follows the reaction shown below:
\[ C_6H_6 + O_2 \rightarrow CO_2 + H_2O \]
Atomic weights of C, H, and O are 12, 1, and 16 respectively. If an aerobic system has 1,000 mg/L of benzene, the amount of oxygen required to completely biodegrade the benzene is most nearly:

\textbf{A.} 980 g

\textbf{B.} 1,860 g

\textbf{C.} 2,680 g

\textbf{D.} 3,080 g

Answer: D
Subdiscipline: water resources

\textbf{Question 109:} The chemical reaction of arsenic trioxide, \( As_2O_3 \) with carbon can be presented as follows:
\[ As_2O_3 + 3C \rightarrow 3CO + 2As \]
The atomic weights of arsenic (As), oxygen (O), and carbon (C) are 75, 16, and 12 respectively. If 1 standard mole of arsenic trioxide reacts with carbon, then the formation will result in:

\textbf{A.} 75 grams of As

\textbf{B.} 36 grams of CO

\textbf{C.} 150 grams of As

\textbf{D.} Greater amount by weight of CO than of As

Answer: C
Subdiscipline: water resources

\textbf{Question 110:} A surface water treatment plant has several filters with a surface area of 150 ft² each. The filter backwash rate is... \\
The backwash duration is 12 min. The volume (gal) of water required for the backwash of each:

\textbf{A.} 4,800

\textbf{B.} 16,200

\textbf{C.} 27,000

\textbf{D.} 32,200

Answer: C
Subdiscipline: geotechnical

A retaining wall is designed to retain a backfill consisting of two soil layers. Assume a smooth wall-soil interface (no friction between the wall and the soil). What is the location of the resultant active earth force from the bottom of the wall if Soil profile:
- Top layer (Layer 1): 6 ft high, unit weight γ = 123 pcf, friction angle φ = 32°, cohesion c = 0 psf
- Bottom layer (Layer 2): 11 ft high, unit weight γ = 129 pcf (saturated), friction angle φ = 38°, cohesion c = 0 psf
The water table starts at the top of the second layer

Answer: 5.01
Subdiscipline: structural

A 2 in diameter shaft of 3 ft in length is clamped at one end and is free at the other end. a 1.5 inch diameter concentric bore is to be made in this shaft from the free end extending inward. Determine the required length of the bore such that the shaft would twist a total of 0.12 degree due to application of an end torque of 900 in lb. Let G= 12* 10^6 psi

Answer: 17 inches
Subdiscipline: structural

a rectangular bar bent into semi circle is built in at one end and is subjected to an internal radial pressure p lb per unit length. write general expression for m(theta)

Answer: pr^2 (1 - cos(theta))
Subdiscipline: structural

A 3 hinged parabolic arch hinged at supports and the crown has a span of 24 m and a central rise of 4 m. It carries a concentrated load of 50 KN at 18 m from left support and a uniformly distributed load of 30 kN/m over the left half portion. Determine the moment at section 6m from the left suport.

Answer: 232.5 kNm
Subdiscipline: structural

In case of 3 hinged arch at a particular point V is vertical shear, H is horizontal thurst,  and theta is the angle made by tangent to horizontal. The normal thurst N and radial shear Q are given by?

Answer: H cosθ + V sinθ and Vcosθ - Hsinθ