Civil Engineering (Technical Subject Paper)
The RPSC Assistant Engineer (Civil) technical paper samples the civil engineering degree syllabus, not one branch. Questions come from building materials, RCC and steel design, strength of materials and structural analysis, fluid mechanics, irrigation and hydrology, water supply, transportation, surveying, soil mechanics and estimating. Rajasthan public-works examples may frame a question, but marks come from code fundamentals.
Code rules that carry marks
- Concrete: IS 456:2000 limit-state design uses partial safety factors 1.5 for dead and live load, 1.2 with earthquake, and 0.9 dead load for stability. Minimum RCC grades: M20 mild, M25 moderate, M30 severe, M35 very severe, M40 extreme; nominal cover 20, 30, 45, 50 and 75 mm.
- Cement and mix: OPC 33, 43 and 53 grades follow IS 269, IS 8112 and IS 12269; mix design follows IS 10262:2019. Cube strength uses 150 mm cubes at 28 days; cylinder strength is about 0.8 of cube strength.
- Steel: IS 800:2007 limit-state design uses γm0 = 1.10 for yielding and γm1 = 1.25 for ultimate resistance.
- Soil: γd = Gγw/(1+e) and Se = wG link the phase relationships.
- Irrigation: delta (m) = 8.64B/D for base period B in days and duty D in ha/cumec.
Worked example
A soil sample has mass 1.80 kg, volume 1.00 litre, water content 15% and G = 2.70. Bulk density = 1.80/0.001 = 1800 kg/m³. Dry density = 1800/1.15 = 1565 kg/m³, so γd = 15.35 kN/m³. From γd = Gγw/(1+e), 1+e = (2.70×9.81)/15.35 = 1.725, giving e = 0.725. Then S = wG/e = (0.15×2.70)/0.725 = 0.559, or 55.9%. The reasoning depends on converting litres to m³ before dividing.
Traps
- Using overall depth instead of effective depth in RCC checks, or forgetting cover when calculating d.
- Treating the levelling arithmetic check as an error check: it misses intermediate-sight and compensating errors.
- Confusing nominal and design mixes; a richer nominal mix is not a designed mix.
- Using 10 instead of 9.81 kN/m³ for water, which shifts e and S.