DDA JE Civil cheat sheet

Concrete mix by volume (nominal): M5=1:5:10, M7.5=1:4:8, M10=1:3:6, M15=1:2:4, M20=1:1.5:3, M25=1:1:2 (cement:sand:coarse aggregate); M25 and above are design mixes.

Bulking of sand: % bulking = [(bulk volume − dry volume)/dry volume] × 100; fine moist sand can bulk 20–30%, so field volume batching must be corrected for moisture.

Slump values (IS 456): 25–75 mm for RCC beams/slabs, 75–125 mm for columns and retaining walls, 10–25 mm for mass concrete; low slump = stiff mix.

Water–cement ratio governs strength: Abram's law fc = A/B^(w/c); lower w/c gives higher strength but reduces workability; minimum cement content and maximum w/c are durability-driven, not strength-driven.

Bulk density and specific gravity: G = (W2 − W1)/[(W2 − W1) − (W3 − W4)] for aggregates; typical coarse aggregate specific gravity 2.6–2.8.

Standard proctor (light) compaction gives OMC and MDD; heavier compaction (modified proctor) lowers OMC and raises MDD. Zero-air-void line bounds all compaction curves.

Bearing capacity: Terzaghi strip footing qult = cNc + γDfNq + 0.5γBNγ; for square footing replace 0.5γBNγ by 0.4γBNγ and cNc by 1.3cNc.

Levelling: rise = backsight − foresight; reduced level of next point = RL of previous point + rise (or − fall); arithmetic check ΣBS − ΣFS = last RL − first RL.

SFD/BMD rules: shear is zero where bending moment is maximum; a point load causes a shear jump and a BM kink; a UDL gives linear shear and parabolic BM; a pure moment gives constant BM.

Coding–decoding: check letter-position shifts (A=1 … Z=26) first; if shifts alternate, apply +1, −2, +3 … pattern or reverse alphabet (A↔Z, B↔Y) mapping.

Series completion: test differences, then second differences, then ratios; for mixed series split into odd-position and even-position sub-series.

Blood relations: draw a family tree with gender marks; 'brother of my father's only son' = the speaker himself, while 'son of my grandfather's only child' = father or aunt/uncle depending on gender.

Direction sense: use a compass sketch; final displacement = √(Σx² + Σy²); left/right turns change heading by 90° each, and two same-side turns give a 180° reversal.

Syllogism: apply Venn diagrams; 'All A are B' + 'All B are C' gives 'All A are C'; 'Some A are B' is always reversible, 'All A are B' is not.

Seating arrangement: fix the facing direction first (north-facing: left = west); for circular arrangements with n people, neighbours of a person are fixed once two positions are anchored.

Number analogy: test squares/cubes, prime positions, digit sums, and products of digits; e.g. 8:512 follows cube relation.

Clock: angle between hands = |30H − 5.5M| degrees; hands coincide 11 times in 12 hours and are opposite 11 times.

Calendar: odd days - ordinary year 1, leap year 2; a century has 5 odd days for 100/200/300 years and 6 for 400 years.

Constitution adopted 26 November 1949, came into force 26 January 1950; Constituent Assembly formed under Cabinet Mission Plan 1946; Dr B. R. Ambedkar chaired the Drafting Committee.

Fundamental Rights are Part III (Articles 12–35); Right to Constitutional Remedies (Art. 32) is called the 'heart and soul' of the Constitution by Ambedkar.

Directive Principles are Part IV (Articles 36–51), non-justiciable; Fundamental Duties are Part IVA (Article 51A), added by the 42nd Amendment 1976 on Swaran Singh Committee recommendation.

President: elected indirectly by electoral college, term 5 years, impeached under Article 61; money bills introduced only in Lok Sabha with President's recommendation (Article 110).

Indian geography: Tropic of Cancer passes through 8 states; Western Ghats are a biodiversity hotspot; Deccan trap soil is black cotton soil rich in montmorillonite.

Rivers: Ganga longest in India, Brahmaputra steepest gradient in Assam, Godavari largest peninsular river; Indus Waters Treaty 1960 allocates eastern rivers to India.

Physics basics: SI unit of force is newton, pressure pascal, work joule; speed of light ≈ 3×10^8 m/s; acceleration due to gravity ≈ 9.8 m/s².

Indian economy institutions: RBI established 1935, nationalised 1949; SEBI 1992 statutory; NITI Aayog replaced Planning Commission on 1 January 2015.

National symbols and facts: national bird Indian peacock, national aquatic animal Ganges river dolphin, national heritage animal Indian elephant.

Subject–verb agreement: singular subject takes singular verb; 'one of + plural noun' takes a singular verb; 'each, every, either, neither' are singular.

Articles: 'a' before consonant sounds, 'an' before vowel sounds (an hour, a university); 'the' with superlatives, unique things, rivers, and ordinals.

Tenses: present perfect (has/have + past participle) for past action with present relevance; past perfect (had + participle) for the earlier of two past actions.

Prepositions: 'since' with a point of time, 'for' with duration; 'between' for two, 'among' for more than two; 'discuss' and 'reach' take no preposition.

Active to passive: object becomes subject, verb becomes be + past participle, agent with 'by'; only transitive verbs passivise.

Direct to indirect speech: present tense changes to past, 'this' to 'that', 'today' to 'that day', 'tomorrow' to 'the next day'; questions use 'asked if/whether'.

Common error traps: 'cope with', 'comprise' (no 'of'), 'superior to' (not 'than'), 'prefer to … rather than', 'hardly had … when'.

One-word substitutions: altruist (selfless), misanthrope (hates mankind), optimist (hopeful), pessimist (negative), stoic (indifferent to pleasure/pain).

Idioms: 'at the eleventh hour' means at the last moment; 'a bolt from the blue' means a sudden shock; 'to burn the midnight oil' means to work late.