Civil Engineering UPSC PYQ 2020

The table given below shows a project's activities along with starting and finishing time and the budgeted cost. The conditions of contract allow measurements to be made monthly and payment of the amount certified less 5% retention to be paid to the contractor after a month of submission of bills. The first bill will be submitted after a month and subsequently every month. The retention amount is to be released after 6 months of completion of the project. The annual interest rate is 15% on locked-up capital. Calculate the total profit of the contractor if he earns 10% profit on the quoted cost. Activity A: starting month 0, duration 2 months, cost Rs 4.5 lakh/month; B: starting month 1, duration 3 months, Rs 4 lakh/month; C: starting month 3, duration 1.5 months, Rs 12 lakh/month; D: starting month 3, duration 1 month, Rs 15 lakh/month; E: starting month 3.5, duration 1.5 months, Rs 4 lakh/month; F: starting month 5, duration 1 month, Rs 20 lakh/month. All activities are independent.

Design a full penetration butt weld to connect a 16 mm thick bracket plate perpendicular to the flange of a column. A factored load of 230 kN is applied to the bracket at a distance of 350 mm from the flange of the column. Field welds and steel of grade Fe 250 were used. Also give a neat sketch of the connection. Use limit state procedure.

Enumerate various types of track junctions. Calculate all the elements required to set out a 1 in 12 turnout taking off from a straight BG track with its curve starting from the toe of the switch, i.e., tangential to the gauge face of the outer main rail and passing through the theoretical nose of crossing (TNC). The heel divergence is given as 11.4 cm.

A cantilever beam is in the form of a quarter of a circle of radius R in a vertical plane and is subjected to a vertical load P at its free end as shown in the figure. Find the vertical and horizontal displacements at the free end, if flexural rigidity is the same throughout the length of the cantilever.

What do you understand by the orientation of the building? What factors will you consider with respect to building orientation? Justify with an example if you have to decide the orientation in cold climate zone. Will it be different in India and Australia for same season?

A cohesionless soil specimen in a triaxial test is subjected to a major and minor principal stress sigma1 and sigma3 respectively. Draw Mohr's circle and derive an expression for phi in terms of sigma1 and sigma3. Also derive the expressions for shear stress, tau and normal stress, sigma on the failure plane in terms of sigma1, sigma3 and phi.

A certain fluid is flowing through the pipe bend as shown in the figure below (laid horizontal). Determine the forces exerted by the pipe boundary on the fluid, if given that p1 = 2.452 bar (gauge), v1 = 4.0 m/s, D1 = 0.3 m, D2 = 0.15 m, theta = 60 degrees and rho = 1000 kg/m^3.

The following consecutive readings were taken with a dumpy level and a 4 m levelling staff on continuously sloping ground at 30 m intervals: 0.680, 1.455, 1.855, 2.330, 2.885, 3.380, 1.055, 1.860, 2.265, 3.540, 0.835, 0.945, 1.530, 2.250. The RL of the starting point was 80.750 m. (i) Rule out a page of level book and enter the above readings. (ii) Carry out reductions of heights by collimation method. (iii) Determine the gradient of the line joining the first and last point. Apply arithmetic check.

What is rotary intersection? Sketch a rotary showing its various elements. What are the guidelines for selecting a rotary type of intersection?

A two-lane pavement (7 m) on a National Highway in hilly terrain (snow-bound) has a curve of radius 60 m. The design speed is 40 km/hr. Determine the length of the transition curve. Determine the total length of the curve and the tangent length if the deflection angle is 60 degrees. Assume e = 0.07; the rate of attainment of superelevation = 1 in 60; C = 80/(75+V), subject to a maximum of 0.8 and a minimum of 0.5; rotation of superelevation about the pavement centreline.

A welded plate girder 22 m in span is laterally restrained throughout, and carries a uniformly distributed load of 100 kN/m excluding the self weight. The girder is without intermediate transverse stiffeners. The steel used is of grade Fe 410. Design the cross-section and the welded connections. Draw a neat sketch of the designed section. Use limit state design method. The plate girder is fabricated in the workshop.

An oil of viscosity 18 poise flows between two horizontal fixed parallel plates which are kept at a distance of 150 mm apart. The maximum velocity of flow is 1.5 m/s. Find: (i) Pressure gradient (ii) Shear stress at the two horizontal parallel plates (iii) Discharge per unit width for laminar flow of oil.

An unsupported cut is made at a site as shown in the figure below: a vertical cut of depth 4 m in a soil with unit weight gamma = 18.0 kN/m^3, cohesion c = 25 kN/m^2 and angle of internal friction phi = 10 degrees. Determine: (i) Lateral stress at the top and bottom of the cut. (ii) The maximum depth of potential tension crack. (iii) The maximum depth of unsupported cut possible at the site. (iv) If the soil is excavated upto 8 m depth and supported by a vertical earth retaining wall, the total active thrust on the wall.

Determine the effective net area for the angle section ISA 125 x 95 x 10 mm shown in the figure, subjected to tensile force, with 18 mm diameter bolts staggered at 50 mm pitch (35 mm edge distance, 50 mm gauge) in one leg and 20 mm diameter bolts at 100 mm pitch (at 55 mm and 40 mm from the heel) in the other leg. Bolts are of grade 4.6, and the steel is of grade Fe 410.

Explain the conditions when vane shear test is suitable for determining the shear strength of the soil. Derive an expression for shear strength of soil in terms of applied torque and vane dimensions considering shearing at top, bottom and surrounding soil. An in situ vane shear test was conducted in a clay soil at the bottom of a borehole. A torque of 150 N-m was required to shear the soil. What was the undrained shear strength of clay neglecting shearing resistance at the top? The vane was 100 mm in diameter and 150 mm long.

To compute the discharge in a small stream by velocity-area method, the stream width was divided into seven segments of 1.5 m width each. The average depths and the velocities measured in the segments by current meter are given in the table below. Compute the discharge in the stream: Segment 1, average depth 0.4 m, velocity at 0.6d = 0.4 m/s; Segment 2, depth 0.7 m, velocity at 0.2d = 0.76, at 0.8d = 0.70 m/s; Segment 3, depth 1.2 m, at 0.2d = 1.13, at 0.8d = 1.19 m/s; Segment 4, depth 1.4 m, at 0.2d = 1.25, at 0.8d = 1.29 m/s; Segment 5, depth 1.1 m, at 0.2d = 1.09, at 0.8d = 1.13 m/s; Segment 6, depth 0.8 m, at 0.2d = 0.69, at 0.8d = 0.65 m/s; Segment 7, depth 0.45 m, velocity at 0.6d = 0.42 m/s.

The rainfall of magnitude 40 mm and 30 mm occurring on two consecutive 4-hour durations on a catchment area of 30 km^2 produced the following hydrograph of the flow at the outlet of the catchment: Time from start of rainfall (hr): -12, 0, 12, 24, 36, 48, 60, 72, 90, 108; Observed flow (m^3/s): 7, 5, 15, 27, 22, 17, 13, 9, 5, 5. Assuming a constant base flow of 5 m^3/s, determine the rainfall excess and the phi-index.

Enumerate the methods of adjustments of a closed traverse. A straight line AC of length 2000 m is required to be set out at right angle to a given line AB. This is done by traversing from A towards C. The observations are as follows: Line AB, Length -, Bearing 360 deg 00' 00"; Line AD, Length 731 m, Bearing 113 deg 48' 00"; Line DE, Length 467 m, Bearing 81 deg 18' 00"; Line EF, Length 583 m, Bearing 105 deg 57' 00". Compute the necessary length and bearing of FC.

A small T-beam is used in an inverted position to span 400 mm. Find the value of P if, due to the application of three forces P, P and 3P shown in the figure (acting at 100 mm, 200 mm and 250 mm respectively from one end of the 400 mm span), the longitudinal gauge at A registers a compressive strain of 50 x 10^-5. Also determine the maximum bending stresses in the beam. Given: E = 200 GPa. Section A-A (T-section) has flange width 12 mm, flange depth 4 mm, and web width 4 mm, overall depth 12 mm, with the strain gauge A located 3 mm from the top.

Find the expression for boundary layer thickness (delta), shear stress (tau_0) and average coefficient of drag (c_f bar) in terms of Reynolds number, if the velocity profile of the laminar boundary layer is given as: u/U = y/delta.

A square footing 0.3 m x 0.3 m is placed on the surface of dense cohesionless sand with unit weight 18.0 kN/m^3 and subjected to a load test. If the footing fails at a load of 47.5 kN, what is the value of phi for the sand (using standard bearing capacity factor tables for Nc, Nq, Ngamma)? If a footing of size 1.5 m x 1.5 m is proposed on the same soil with a depth of foundation 1.0 m, what will be the allowable capacity of the footing with a factor of safety of 2.5? In all cases water table was at a great depth and its effect is to be ignored.

Analyse the propped cantilever AB (fixed at A, roller support at B, carrying a uniform load w = W/L over its span L) shown in the figure below and determine the collapse load.

Discuss the positive and negative impacts on environment due to river valley projects.

A pit is to be excavated in a fine sand stratum completely saturated up to the ground surface. The void ratio of the soil was 0.5 and specific gravity of soil solids is 2.7. The pit is to be dug to a depth of 6.3 m. To stabilise the bottom of the excavation (to prevent sand boiling) it is decided to drive steel sheet piles to act as cut-off walls that encircle the excavation. Determine the minimum depth of sheet piling required for an impending quick condition. Derive the formula, if any, used. Use unit weight of water as 9.81 kN/m^3.

Two footings are placed at a depth of 1.0 m on a sand layer as shown in the figure below. The footing at the left is of size 2 m x 2 m and that at the right 1.5 m x 1.5 m and carry loads of 400 kN and 225 kN, respectively. The sand layer (unit weight 18.0 kN/m^3, water table at ground level) is 1 m thick, underlain by a compressible clay layer 3 m thick (Cc = 0.4, e0 = 1.0, unit weight 17.0 kN/m^3) resting on sand and gravel. If the settlement of the footing is considered only because of the consolidation of the compressible clay layer (ignoring elastic settlement of sand and clay), where do you expect the maximum settlement? Justify your answer. Also determine the maximum consolidation settlement for the footing soil condition shown in the figure. Assume unit weight of water as 9.81 kN/m^3. Assume 2.0 vertical to 1.0 horizontal dispersion of footing pressure over depth.

List the different defects in timber.

Determine the force in members GE, GC and BC of the truss shown in the figure below, where the truss has bottom chord A-B-C-D with panel points at 4 m intervals (total span 12 m), a pin support at A and a roller support at D, top chord joints G (above A, at a height of 3 m) and E (above C), with a horizontal load of 400 N applied at E and a vertical load of 1200 N applied downward at C. Indicate whether the members are in tension or compression.

What are different types of joints in rigid pavements? Design a dowel bar system for a cement concrete slab for the following conditions: Design wheel load = 4100 kg; Design load transfer = 40%; Slab thickness = 20 cm; Joint width = 2 cm; Permissible flexural stress in dowel bar = 1400 kg/cm^2; Permissible shear stress in dowel bar = 1000 kg/cm^2; Permissible bearing stress in concrete = 100 kg/cm^2; K value of subgrade = 8 kg/cm^3; E = 3 x 10^5 kg/cm^2; mu = 0.15.

Using the displacement method, analyse the frame given in the figure below, where a portal frame has fixed supports at A and D, with a vertical member AB of height 6 m, a horizontal member BC of length 6 m carrying a udl of 40 kN/m, a vertical member CD of height 6 m, and an additional horizontal member CE of length 4.5 m with a roller support at E. Flexural rigidity is constant throughout.

The floor slab of a room has clear dimensions of 4.0 m x 9.0 m and the slab is simply supported on 230 mm thick masonry walls. The floor loading consists of a live load of 6 kN/m^2 and dead load due to finishing work of 1.5 kN/m^2. Steel of grade Fe 415 and concrete of grade M 25 is used for construction. Design the floor slab and check it for deflection. Use limit state design method.

What is normal tension? Determine the normal tension for a steel tape supported between two supports 10 m apart if the standard tension is 65 N and the weight of the tape per metre is 0.62 N. Take E = 200 GPa and the area of cross-section as 8 mm^2.

With the aid of neat sketches, describe how a flow-mass curve could be used for the determination of the following: (i) Minimum storage needed to meet a constant demand (ii) Maximum constant maintainable demand from a given storage.

Find out the steepest gradient on a straight track using the following data for a train having 20 wagons: Weight of each wagon = 18 tonnes; Rolling resistance of wagon = 2.5 kg/tonne; Speed of the train = 50 km/hr; Weight of locomotive with tender = 120 tonnes; Tractive effort of locomotive = 12 tonnes; Rolling resistance of locomotive = 3.5 kg/tonne.

The in situ moisture content of a soil at a borrow area is 14% and its moist unit weight is 17.0 kN/m^3. The specific gravity of the solids of the soil is 2.7. The soil is to be excavated and transported to a construction site for use in a compacted fill. The finished compacted volume is 2500 m^3. If the specifications call for the soil to be compacted to a dry unit weight of 18.0 kN/m^3 at the moisture content of 16%, determine the volume of soil to be borrowed from the borrow site. Also determine the degree of saturation of the soil after compaction and amount of water to be added to the borrow soil to achieve the desired compaction. Assume unit weight of water = 9.81 kN/m^3.

If an 8 degree curve track diverges from a main curve of 5 degrees in an opposite direction in the layout of a BG yard, calculate the superelevation and the speed on the branch line if the maximum speed permitted on the main line is 45 km/hr.

An 8 m long beam is loaded with a uniformly distributed load, w/m over the entire span. The beam is supported at supports A and B as shown in Figure (a), with a 6 m main span AB plus a 2 m overhang beyond B. The bending moment diagram for the beam is shown in Figure (b), which is positive over the 6 m span and has a negative peak value of 30 kN-m over the overhang. Determine the value of the udl, w, and draw the shear force diagram. Also determine the maximum bending moment in the beam and its point of application.

Blocks A and B are connected through a cord and rest on the inclined planes as shown in the figure below (two inclined planes meeting at an apex C with a frictionless pulley, the left incline at 60 degrees carrying block A with coefficient of friction 0.2, and the right incline at 30 degrees carrying block B with coefficient of friction 0.2). What is the tension in the cord, if the friction at block A reaches the maximum value? Assume that pulley at C is frictionless. Block A weighs 300 N and Block B weighs 400 N.

The drag of a sonar transducer is to be predicted, based on wind tunnel test. The prototype, a 0.3 m diameter sphere, is to be towed at 2.57 m/s in sea water at 4.5 deg C. The model is 152 mm in diameter. Determine the required test speed in air. If the drag of the model at these test conditions is 2.7 N, estimate the drag of the prototype. Given that at 4.5 deg C, rho(sea water) = 1000 kg/m^3, nu(sea water) = 1.57 x 10^-6 m^2/s and at STP, rho(air) = 1.227 kg/m^3, nu(air) = 1.46 x 10^-5 m^2/s.

Determine the yield from a tube well of 200 mm radius penetrating in an unconfined aquifer of depth 18 m. The depth of water in the well, after drawdown, is 12 m. The permeability of soil is 25 m/day and the radius of the circle of influence is 250 m.

A watercourse has culturable commanded area of 2600 hectares, out of which the intensities of irrigation for perennial sugarcane and rice crops are 20% and 40%, respectively. The duties for these crops at the head of the watercourse are 750 hectares/cumec and 1800 hectares/cumec, respectively. Find the discharge required at the head of the watercourse if the peak demand is 120% of the average requirement.

Draw characteristic stress-strain curve for concrete, mild steel and HYSD steel in flexure giving all relevant values as per codal recommendations for limit state design of RCC structures.

What are the main factors that affect the selection of type of dam?

A 1.5 cm wide gap between two vertical plane surfaces is filled with an oil of specific gravity 0.9 and dynamic viscosity 2.0 Ns/m^2. A metal plate 1.0 m x 1.0 m x 0.1 cm thick and weighing 20 N is placed midway in the gap. Find the force required if the plate is to be lifted up with a constant velocity of 0.1 m/s.

A 100 km^2 catchment has a 4-hour concentration time with 1-hour intervals, resulting in the following time-area histogram: Time 0-1 hr, Area 10 km^2; 1-2 hr, 30 km^2; 2-3 hr, 20 km^2; 3-4 hr, 40 km^2. A 6-hour storm has the following effective rainfall hyetograph ordinates: Time (hr) 0-1, 1-2, 2-3, 3-4, 4-5, 5-6; Effective rainfall (mm/hr) 5, 10, 20, 15, 10, 5. Use the time-area method to calculate the outflow hydrograph for this catchment.

Specify the laboratory tests conducted on cement. Also indicate the permissible values of the cement for corresponding tests (for ordinary Portland cement).

Give five main human actions that affect the hydrological cycle and identify the components affected by each of these.

What do you understand by percent swell and load factor? How is the load factor related to swelling of the material? How does it affect the transporting of material?

Determine the aeration period, food to microorganism (F/M) ratio (in kg BOD/day/kg MLSS), percentage (%) efficiency of BOD removal and sludge age (in days) for the given operating data for a conventional sludge treatment plant: Wastewater flow = 45000 m^3/day; Volume of aeration tank = 15000 m^3; Influent BOD = 250 ppm; Effluent BOD = 25 ppm; Mixed liquor suspended solids (MLSS) = 2500 mg/L; Suspended solids in effluent = 50 mg/L; Suspended solids in waste sludge = 11000 mg/L; Quantity of waste sludge = 220 m^3/day.

A reinforced concrete beam having a clear simply supported span of 6 m is required to support live and superimposed loads of 18 kN/m and 12 kN/m respectively. The materials to be used are M 25 grade concrete and Fe 250 grade steel. Design the section of the beam, and the main longitudinal reinforcement. The width of support is 500 mm. Use limit state design method.

A Pelton wheel develops 15000 kW power under a head of 250 m. Find rotational speed of wheel, number of jets required, size of each jet, dimensions of buckets and number of buckets. Given: Cv = 0.98, Ku = 0.46, eta_o = 0.88, D/d = 14 and specific speed = 30.

Water has to be supplied to a town with one lakh population at the rate of 150 litres/capita/day from a river 2000 m away. The difference in elevation between the lowest water level in the sump and reservoir is 36 m. If the demand has to be supplied in 8 hours, determine the size of the main pipe and the horsepower (BHP) of the pumps required. Assume the maximum demand as 1.5 times the average demand. Assume coefficient of friction, f = 0.03, velocity in the pipe 2.4 m/s and efficiency of pump 80%.

During a BOD test conducted on a 5% dilution of waste, the following observations were taken: DO of aerated water used for dilution = 3.6 mg/L; DO of original sample = 0.8 mg/L; DO of diluted sample after 5 days' incubation = 0.7 mg/L. Compute: (i) 5 days' BOD (ii) Ultimate BOD. Assume deoxygenation constant at test temperature as 0.12.

A hydraulic jump occurs in a triangular channel having sides sloping at 45 degrees. Derive an equation relating two depths and the flow rate. If the depths before and after the jump in the channel are 0.5 m and 1.0 m, find out the flow rate and Froude numbers before and after the jump.

Two steel plates, each 100 mm wide and 10 mm thick, are connected together by a lap joint using a single row of three bolts, along width, of property class 4.6. The diameter of each bolt is 16 mm and the ultimate tensile strength of steel plates is 410 N/mm^2. Calculate the efficiency of the joint if the plates are in tension. Use limit state procedure. Given: fub = 400 N/mm^2 for bolts of property class 4.6.

Find the dimensions of a rectangular sedimentation tank for the following data: Volume of water to be treated = 3 million litres per day; Detention period = 4 hours; Velocity of flow = 10 cm/min.

Design a trapezoidal alluvial channel using Kennedy's theory. The channel carries a discharge of 30 m^3/s with critical velocity ratio 1.0 and Manning's roughness coefficient n equal to 0.0225. Assume that the bed slope is equal to 1 in 5000 and the trapezoidal channel has a side slope of 1 H : 2 V.

A shop building gets an annual rate of return of Rs 35,000. The future life of the building is estimated as 12 years. But if recommended repairs are carried out immediately at an estimated cost of Rs 3,00,000, it is expected that the building will last for 30 years more. Assuming the rate of interest as 8%, determine whether it is economical to carry out the recommended repairs or leave as it is. Justify your answer.