TNPSC AE Civil cheat sheet

Concrete mix design by IS 10262: target mean strength f'ck = fck + 1.65 s, where s is the assumed standard deviation (e.g., 4 N/mm² for M20, 5 for M25–M30); water-cement ratio from IS 456 durability tables governs the maximum permissible w/c.

Flexural design of a singly reinforced rectangular section (limit state): Mu = 0.87 fy Ast d (1 − fy Ast / (fck b d)); xu/d must not exceed 0.48 for Fe 415 and 0.46 for Fe 500 to ensure ductile failure.

Shear in beams per IS 456: nominal shear stress τv = Vu/(b d) must not exceed τc,max (e.g., 3.1 N/mm² for M20, 3.5 for M25); minimum shear reinforcement Asv/(b sv) ≥ 0.4/(0.87 fy).

Bearing capacity: Terzaghi's strip footing qu = c Nc + q Nq + 0.5 γ B Nγ; for a square footing the last term becomes 0.4 γ B Nγ and for a circular footing 0.3 γ B Nγ. Safe bearing capacity = qu/FOS + γ Df (net).

Surveying: the prismatic compass reads whole-circle bearings (0°–360°), while the surveyor's compass reads quadrantal bearings (0°–90° with NE/SE/SW/NW prefixes). True bearing = magnetic bearing + magnetic declination (east positive).

Fluid mechanics: Bernoulli's equation p/γ + v²/(2g) + z = constant along a streamline for steady, incompressible, frictionless flow; continuity for a pipe A1V1 = A2V2; discharge over a rectangular weir Q = (2/3) Cd √(2g) b H^(3/2).

Transportation: the IRC stopping sight distance SSD = 0.278 V t + V²/(254 f), with V in km/h, reaction time t typically 2.5 s and longitudinal friction f about 0.35–0.40; overtaking sight distance uses the slower-vehicle speed in the second term.

Environmental engineering: BOD5 is measured at 20 °C over 5 days; the first-stage BOD exerts about 68% of ultimate BOD (k ≈ 0.23/day base 10). Standard rate of filtration for a slow sand filter is 100–200 L/m²/h, and for a rapid sand filter 3,000–6,000 L/m²/h.

Indian Constitution: adopted 26 November 1949, came into force 26 January 1950; the Preamble was amended by the 42nd Amendment (1976) to add 'socialist', 'secular' and 'integrity'; the Fundamental Duties (Article 51A) were added by the 42nd Amendment on the Swaran Singh Committee's recommendation.

Tamil Nadu geography: the Western Ghats run along the western border, the Eastern Ghats along the north-west; the Cauvery is the principal east-flowing river, and the Palghat Gap is the major break in the Western Ghats between Tamil Nadu and Kerala.

Tamil Nadu districts and administrative facts: the state has 38 districts; Chennai is the capital; the state animal is the Nilgiri tahr, state bird the emerald dove, state tree the palmyra palm, and state flower the glory lily (Gloriosa superba).

Indian polity key articles: Article 14 equality before law, Article 19 six freedoms, Article 21 right to life and personal liberty, Article 32 writ jurisdiction of the Supreme Court, Article 226 writ jurisdiction of High Courts, Article 356 President's rule, Article 368 amendment procedure.

Indian history: the Indian National Congress was founded in 1885 (A.O. Hume); the Jallianwala Bagh massacre occurred on 13 April 1919; the Dandi March began 12 March 1930; the Quit India Movement was launched on 8 August 1942; India attained independence on 15 August 1947.

Science and technology: the SI unit of force is the newton (kg·m/s²), of pressure the pascal (N/m²), and of power the watt (J/s); pH = −log[H⁺]; photosynthesis converts CO₂ and H₂O to glucose and O₂ in the presence of chlorophyll and light.

Current affairs and economy: the Reserve Bank of India was established in 1935 and nationalised in 1949; GST was introduced on 1 July 2017; GDP at constant prices is measured with a fixed base year (2011-12 series in India).

Tamil grammar: Tamil has 12 vowels (uyir), 18 consonants (mei), and 216 compound letters (uyirmei); the aytam (ஃ) is a special letter, and the total alphabet is 247 letters including the grantha letters used for loanwords.

Tamil cases (vetrumai): eight cases are recognised - first (nominative), second (accusative, suffix -ai), third (instrumental, -al/-odu), fourth (dative, -ku), fifth (ablative, -il/-idam), sixth (genitive, -athu/-in), seventh (locative, -il), and eighth (vocative).

Tamil verb forms: the three tenses are present (nirvagam), past (irappu), and future (ethirkalam); the infinitive ends in -ka/-kka, and the negative conjugation uses the suffix -aathu (e.g., seyyaathu = does not do).

Tamil sandhi (punarchi): two words combine with linking letters; the common linking consonants are y, v, and n; e.g., 'maram + vazhi' becomes 'maravazhi' and 'kadu + thodar' becomes 'kaduthodar'.

Tamil literature: Thirukkural by Thiruvalluvar has 133 chapters (adikarams) and 1330 couplets (kural venpa), divided into three books - Aram (virtue), Porul (wealth), and Kamam (love).

Tamil synonyms and antonyms: 'arivu' (knowledge) is synonymous with 'gnanam'; 'periyar' (great) is antonymous to 'siriyar' (small); 'inbam' (pleasure) is antonymous to 'thunbam' (sorrow).

Tamil numerals: the cardinal numerals 1–10 are onru, irandu, moondru, naangu, aindhu, aaru, ezhu, ettu, onbadhu, pathu; the ordinal suffixes are -aavathu (e.g., onraavathu = first).

Percentage and profit/loss: profit% = (SP − CP)/CP × 100; discount% = (MP − SP)/MP × 100; successive discounts of a% and b% equal a single discount of a + b − ab/100 percent.

Time, speed and distance: distance = speed × time; if a train of length L crosses a platform of length P at speed v, time = (L + P)/v; for two trains moving in opposite directions, relative speed = v1 + v2.

Simple and compound interest: SI = P × R × T/100; CI = P[(1 + R/100)^T − 1]; for half-yearly compounding the rate is halved and the number of periods doubled.

Permutations and combinations: nPr = n!/(n − r)!; nCr = n!/[r!(n − r)!]; the number of ways to arrange n objects with p identical of one kind and q identical of another is n!/(p! q!).

Reasoning - series and coding: in an alphabet series, the position of a letter equals its rank (A = 1, Z = 26); a common coding rule shifts each letter by a fixed offset (e.g., +3 gives A→D, B→E).

English grammar: subject-verb agreement - singular subjects take singular verbs; 'each', 'every', 'either', 'neither' are singular; collective nouns take a singular verb when acting as a unit.

English vocabulary: 'ubiquitous' = present everywhere; 'ephemeral' = short-lived; 'lucid' = clear; 'candid' = frank; 'meticulous' = showing great attention to detail.