Civil Engineering 2024 Paper II 50 marks Compulsory Describe

Q1

(a) Describe various defects in clay bricks giving sources/causes of defects. 10 marks (b) Draw neat sketches, showing complete details of plans of alternate courses of a 1½ brick thick masonry wall in English Bond having a right-angled corner. 10 marks (c) Describe the important features of Type 1, Type 2 and Type 3 preservatives used for timber. 10 marks (d) A ship is 55 km away from a lighthouse of height 62 m above mean sea level. An observer standing on the deck of the ship tries to see the lighthouse top. The height of the observer's eye above mean sea level is 10 m. Determine whether the lighthouse top will be visible to the observer or not. If not visible, find out the distance by which the ship has to travel towards the lighthouse so that it becomes visible to the observer. 10 marks (e) An alert driver with a reaction time of 0·75 seconds is driving downhill on a 2·5% grade at 60 kmph on a dry pavement when suddenly a person comes in the path of the driver at a distance of 55 m. Can the driver stop in time with emergency braking? Can the driver stop in time when it is a rainy day? Assume: g = 9·8 m/s², f = 0·4 (dry pavement), f = 0·32 (wet pavement) 10 marks

हिंदी में प्रश्न पढ़ें

(a) मृत्तिका ईंटों के विभिन्न दोषों का वर्णन स्रोतों/कारणों का उल्लेख करते हुए कीजिए। 10 (b) एक समकोणी कोने वाली 1½ ईंट मोटी चिनाई वाली दीवार के लिए अंग्रेजी चाल में एकान्तर रद्दों के अनुविख्षेपों (प्लान) के स्पष्ट चित्र पूरा विवरण दर्शाते हुए बनाइए। 10 (c) इमारती लकड़ी के लिए उपयोग किए जाने वाले टाइप 1, टाइप 2 और टाइप 3 परिरक्षकों के महत्त्वपूर्ण अभिलक्षणों का वर्णन कीजिए। 10 (d) एक जहाज औसत समुद्र तल से 62 मीटर की ऊँचाई वाले लाइटहाउस से 55 किमी की दूरी पर है। जहाज के डेक पर खड़ा हुआ एक पर्यवेक्षक लाइटहाउस के शीर्ष को देखने का प्रयास करता है। औसत समुद्र तल से पर्यवेक्षक की आँख की ऊँचाई 10 मीटर है। ज्ञात कीजिए कि पर्यवेक्षक को लाइटहाउस का शीर्ष दिखाई देगा या नहीं। यदि यह दिखाई नहीं देता है, तो ज्ञात कीजिए कि जहाज को लाइटहाउस की ओर कितनी दूरी तय करनी होगी ताकि पर्यवेक्षक को यह दिखाई देने लगे। 10 (e) 0·75 सेकंड के प्रतिक्रिया काल वाला एक सतर्क चालक 60 किमी प्रति घंटे की गति से 2·5% ढाल वाले सूखे कुंडिम पर नीचे की ओर गाड़ी चला रहा है, जब अचानक 55 मीटर की दूरी पर एक व्यक्ति चालक के रास्ते में आ जाता है। क्या चालक आपातकालीन ब्रेक लगाकर समय पर रुक सकता है? यदि बरसात का दिन हो, तो क्या चालक समय पर रुक सकता है? मान लीजिए कि: g = 9·8 m/s², f = 0·4 (सूखा कुंडिम), f = 0·32 (गीला कुंडिम) 10

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Directive word: Describe

This question asks you to describe. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'describe' demands comprehensive coverage with clear explanations for parts (a), (c) and precise calculations with sketches for parts (b), (d), (e). Allocate approximately 20% time each to all five parts since marks are equal. For (a) and (c), use structured paragraphs with bullet points; for (b), dedicate sufficient space for two neat course plans; for (d) and (e), show all formulas, substitutions, and final answers with units. Begin with a brief introduction acknowledging the diverse nature of building materials and highway engineering, then address each part sequentially, and conclude with practical implications where relevant.

Key points expected

  • Part (a): At least 6-8 brick defects with specific causes (e.g., efflorescence from soluble salts, bloating from over-firing, laminations from air trapped during pugging, cracks from uneven drying, warping from improper stacking, black core from insufficient oxidation)
  • Part (b): Correct English Bond pattern for 1½ brick (13½ inch) thick wall showing alternate courses with proper lap (quarter brick), headers and stretchers arrangement, right-angled corner detail with queen closer placement
  • Part (c): Type 1 (tar-oil creosote, coal tar), Type 2 (water-borne salts like CCA—chromated copper arsenate), and Type 3 (organic solvent type like pentachlorophenol) preservatives with application methods, toxicity, and Indian Standards (IS 401)
  • Part (d): Correct application of dip of horizon formula using Earth's radius (6370 km), calculation of visible horizon distances for both lighthouse and observer, determination of visible overlap, and required distance reduction
  • Part (e): Stopping sight distance calculation using SSD = vt + v²/[2g(f±S)] with proper sign convention for downgrade, comparison with available 55m for both dry and wet conditions

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness20%10For (a), correctly identifies 6+ defects with precise manufacturing-stage causes; for (c), accurately distinguishes all three preservative types by chemical composition, application, and toxicity; for (d) and (e), applies correct fundamental formulas (dip of horizon, SSD on grades) with proper physical understandingIdentifies 4-5 defects with generic causes; describes preservatives with some confusion between types; applies formulas with minor conceptual errors like ignoring grade effect or using approximate Earth radiusLists fewer than 4 defects without clear cause-effect linkage; conflates preservative types or omits key features; uses incorrect formulas or fundamental misconceptions like linear visibility calculation
Numerical accuracy20%10Part (d): Calculates dip distances precisely (d₁=√(2×6370×0.052)≈25.7 km, d₂=√(2×6370×0.01)≈11.3 km), finds invisible gap (18 km), and required distance (43 km from lighthouse); Part (e): Correct SSD = 16.67×0.75 + (16.67)²/[2×9.8×(0.4-0.025)] = 12.5 + 38.6 = 51.1 m (dry, stops in time) and 63.4 m (wet, cannot stop)Correct method but arithmetic errors in final values; uses g=10 m/s² without adjustment; minor unit conversion errors in kmph to m/sMajor calculation errors, wrong formula application, missing unit conversions, or no numerical working shown for computational parts
Diagram quality20%10Part (b): Two meticulously drawn course plans showing 1½ brick thickness (3 bricks in header course, 1½ brick lap), clear distinction between headers and stretchers, proper queen closer at corner, dimension lines, and brick labeling; neat freehand acceptable if proportioned correctlyRecognizable bond pattern but missing details like queen closer, incorrect thickness representation, or poor proportion between header and stretcher coursesNo diagram, unrecognizable bond pattern, single course only, or diagram copied without understanding the 1½ brick thickness requirement
Step-by-step derivation20%10For (d): Explicitly states formula d=√(2Rh), derives combined visibility condition, shows inequality for invisible case, and solves for required distance; for (e): Writes general SSD formula, explains sign convention for downgrade, substitutes values systematically with intermediate stepsShows main formulas and final substitution but skips intermediate algebraic steps; presents calculations without explaining the physical reasoningJumps to final answer without derivation, missing essential steps, or presents disconnected numbers without formulaic basis
Practical interpretation20%10For (a), links defects to IS 1077 quality grades and field rejection criteria; for (c), notes environmental/health regulations (CCA restrictions); for (d), relates to nautical chart reading and lighthouse visibility ranges; for (e), interprets as justification for speed limits, warning signs, and wet weather driving advisories on NH/SH gradesMentions practical relevance superficially without specific standards or applications; generic statements about safety without connecting to calculated valuesNo practical interpretation; treats all parts as purely theoretical; fails to draw conclusions from numerical results (e.g., whether driver can stop)

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