UPSC Civil Engineering 2021 — Paper II

(a) (i) What is the purpose of first coat of plastering ? (ii) What loads are taken by the formwork apart from its self-weight ? (iii) Label the components (1, 2, 3 & 4) of pitched roof shown in the figure. 10 marks (b) Convert the given A-O-A (Activity on Arrow) to A-O-N (Activity on Node) Network and indicate the critical path. The duration of each activity is shown in the figure. 10 marks (c) The staff reading taken on a staff held at a distance of 80 m from the instrument when the bubble central was 1·455 m. When the bubble is moved 6 divisions out of centre, the staff reading observed is 1·487 m. If the length of one division is 2 mm, find the radius of curvature and the sensitivity of the tube. 10 marks (d) What is vertical curve and its significance ? Draw summit as well as valley curve for the following conditions : (i) Upward gradient (+g₁%) followed by another upward gradient (+g₂%) (ii) Downward gradient (−g₁%) followed by another downward gradient (−g₂%) 10 marks (e) A locomotive on M. G. Track has three pairs of driving wheels each carrying 20 tonnes. What maximum load can it pull on level track with curvature of 2° at 50 km/hr ? Take coefficient of friction = 0·166. 10 marks

(a) For a small project, the number of masons required is shown. The table also indicates the duration of each activity along with the masons required. Carry out the resource allocation with unlimited and limited number of resources. Indicate the advantages and disadvantages of both. 20 marks (b) There is a horizontal curve of radius 400 m and length 200 m on a highway. Compute the set-back distances required from the centre line on the inner side of the curve so as to provide for : (i) stopping sight distance of 100 m (ii) safe overtaking sight distance of 320 m The distance between the centre lines of the road and the inner lane is 1·9 m. 15 marks (c) A dumpy level was set up at P exactly between A and B, 50 m apart. The readings on staff held at A and B were 2·4 m and 1·4 m respectively. The instrument was then shifted and set up at Q on the line BA produced at 10 m from A. The readings on staff held at A and B were respectively 2·50 m and 1·4 m. Determine the staff reading on A and B to give a horizontal line of sight. Determine R.L. of B if that of A is 200·00 m. 15 marks

(a) (i) Explain with neat sketches, how surface and sub-surface water can be removed from a railway track. (ii) Two high level platforms are to be provided on the inside as well as the outside of a 2° curve on a BG track with a super-elevation of 100 mm. What should be the required extra clearances for these platforms, both on the inside and the outside of the curve (length of bogie = 21·34 m, C/C bogie distance = 14·785 m, height of platform = 840 mm). 10+10 (b) The altitude of two proposed stations A and B 130 km apart are respectively 225 m and 1160 m. The altitude of two peaks C and D on the profile between them are respectively 308 m and 632 m, the distance being AC = 50 km and AD = 90 km. Determine whether A and B are intervisible, and if necessary find the minimum height of a scaffolding at B, assuming A as the ground station, to make them intervisible. 15 (c) How do you define an infrastructure project ? How do you compare BOO and BOOT models ? Draw a typical structure of a BOOT project. 15

(a) Design the size and spacing of dowel bars at the expansion joints of a cement concrete pavement of thickness 25 cm with radius of relative stiffness 80 cm, for a design wheel load of 5000 kg. Assume load capacity of dowel system as 40% of the design wheel load. Joint width is 2.0 cm, permissible shear and flexural stresses in dowel bar are 1000 kg/cm² and 1400 kg/cm² respectively and permissible bearing stress in cement concrete is 100 kg/cm². 20 (b) Work out the cost of a plot, in terms of per m² of land measuring 60,000 sq m. The cost of development for roadways, water supply, sewerage system, electricity and all other engineering works is Rs. 100/- per sq m, which is spent in following manner : First year : 10%, second year : 15%, third year : 20% and fourth year remaining area. Average market rate for plot is Rs. 5000/- per sq m. 10%, 20%, 20% and 30% plots are sold in first, second, third and fourth year respectively whereas remaining plots are sold in fifth year. Assume the discount rate = 7%. Write your assumptions clearly, if any (like stamp duty, etc.) 15 (c) (i) Indicate (in bulleted form) the advantages of ferro-cement over the conventional RCC. Can we use the ferro-cement tanks for high capacity like 25000 litres or above ? Justify your answer. (ii) Label the terms (technical) that applies to the door (shown in figure) parts. 10+5

(a) A one-hour unit hydrograph of a catchment is shown in the figure. A storm of two hours duration with intensity of 70 mm/h in the first hour and 40 mm/h in the second hour occurs over the catchment. Calculate the peak direct surface runoff value in m³/s. (10 marks) (b) A temporary coffer dam is to be built to protect the 5 year construction activity for a major river valley project. If the coffer dam is designed to withstand the 25-year flood, what is the risk that the structure will be overtopped in the third year? (10 marks) (c) A weir across an alluvial river has a horizontal floor length of 50 m and retains 5 m of water under full flow condition. The downstream sheet pile is driven to a depth of 5 m below the impervious floor of negligible thickness. Determine the exit gradient. (10 marks) (d) What is an indicator organism ? Discuss the required characteristics for an ideal indicator organism. Name any two indicator organisms. (10 marks) (e) Circular sewer of minimum diameter of 150 mm is recommended for the house connections. Calculate the discharge carried by this sewer, when flowing full, laid at a slope of 0·004. Take Manning's n as 0·013. Why this sewer size has been recommended as the minimum size, when the waste water discharge from individual household will be substantially less ? (10 marks)

(a) Two settling tanks – one rectangular, with length to width ratio of 3 : 1 and side water depth of 3·5 m; and the other circular, with side water depth of 4·0 m – are to be designed to treat 20,000 m³/d of water required for a city's water supply. The surface overflow rate for satisfactory removal of solids is 20 m/d. Determine the dimensions of the settling zone of the two tanks. Check for retention time, horizontal velocity and weir overflow rate which should respectively be 3–5 hours, less than 10 m/h and 6 to 10 m³/h per m. Also determine the overall dimensions of the basins keeping length of inlet zone and outlet zone equal to the side water depth of the basin. (20 marks) (b) Although it would be expected that the value of the ultimate carbonaceous BOD would be as high as the COD, this is seldom the case. What are the reasons for the observed differences? (15 marks) (c) Determine the storage capacity of a reservoir for the given cropping pattern, canal losses are 15% and reservoir losses are 10%. (15 marks)

(a) An open drain is to be designed to prevent waterlogging for an area of 576 ha. Given that the drainage coefficient is 0·06 m/day, determine the capacity of the drain required and the dimensions of the trapezoidal section with side slopes 1 : 1 and Lacey's f=1·0. Also, compute the slope. (20 marks) (b) A 0·5 m diameter well fully penetrates an unconfined aquifer whose bottom is 150 m below the undisturbed ground water table. When pumped at a steady rate of 6·0 m³/min, the drawdowns observed in two observation wells at radial distances of 10 m and 50 m are respectively 10 m and 5 m. Determine the drawdown in the well. (15 marks) (c) What is grit ? Why is it essential to remove the grit ? Why velocity control devices are essential with unaerated horizontal flow grit chambers ? Why are the velocity control devices not required with the aerated grit chambers ? Name any two velocity control devices used with grit chambers. (15 marks)

(a) From the basin map of a given watershed with drainage area 3000 km², the length of the mainstream (L) is measured as 125 km. The distance (Lc) from the outlet to a point on the stream nearest the centroid of the watershed area is measured as 90 km. The regional constant C₁ for the watershed is 0·75 and C₂ = 2·75. From the unit hydrograph derived for the watershed, the following are determined : rainfall duration tR = 12 h, basin lag tpR = 34 h and peak discharge qpR = 135 m³/s. cm. Determine the coefficients Ct and Cp for the synthetic unit hydrograph of the watershed. (20 marks) (b) Describe municipal solid waste sanitary landfill with a schematic diagram showing its various components. (15 marks) (c) Briefly describe the process for the award of environmental clearance for a project according to the EIA Act 2006. (15 marks)