Civil Engineering (Technical Subject)
Civil Engineering (Technical Subject)
The JKSSB JE (Civil) technical paper tests the core subjects of a civil engineering diploma or degree: building materials, concrete technology, surveying, fluid mechanics, soil mechanics, structural analysis and design, transportation, and estimation. Questions mix direct IS-code facts with short numericals, so both recall and calculation speed matter.
Core rules and concepts
- Concrete: grade M20 means a characteristic cube compressive strength of 20 N/mm² at 28 days (IS 456:2000). Nominal mixes are fixed by volume; design mixes follow IS 10262. The water-cement ratio controls strength and durability.
- Surveying: reduce levels by the height-of-instrument (HI) or rise-and-fall method; correct bearings for local attraction; distinguish whole-circle from quadrantal bearings.
- Soil mechanics: void ratio e, porosity n, degree of saturation S, and the relation e = n/(1−n); Atterberg limits; optimum moisture content and maximum dry density from the compaction curve.
- Hydraulics: continuity A₁V₁ = A₂V₂, Bernoulli's equation, Manning's formula, and discharge over weirs and notches.
- Structures: draw shear force and bending moment diagrams; identify maximum BM under point loads; know the limit states of collapse and serviceability.
Worked example
Estimate cement for 1 m³ of M20 nominal mix (1:1.5:3) at w/c = 0.50. Dry volume = 1.54 × 1 = 1.54 m³. Sum of ratios = 5.5. Cement volume = 1.54/5.5 = 0.28 m³. Mass = 0.28 × 1440 = 403 kg. So about 403 kg (8 bags) of cement per m³.
Traps
Do not confuse characteristic strength with target mean strength. Do not use wet volume directly - apply the dry-volume factor. In levelling, a rise gives a smaller staff reading. In soil, void ratio and porosity are not the same number.