SSC JE General Engineering (Civil & Structural) Syllabus

What is the principle of a total station in advanced surveying?

It combines an electronic theodolite (angle measurement) with an electronic distance meter (EDM) and a microprocessor to measure angles and distances and compute coordinates electronically.

How does GPS determine position in surveying?

By trilateration—measuring distances (from signal travel time) to at least four satellites to compute 3D position (latitude, longitude, elevation) and time.

What is 'contour interval' and how is it related to map scale?

Contour interval is the vertical distance between two consecutive contours; it is kept small for large-scale (detailed) maps and flat terrain, and large for small-scale maps and steep terrain.

Define the 'void ratio' and 'porosity' of a soil.

Void ratio (e) = volume of voids / volume of solids; porosity (n) = volume of voids / total volume. They are related by n = e/(1+e).

What are the Atterberg limits of soil?

Liquid limit, plastic limit, and shrinkage limit—water contents marking transitions between liquid, plastic, semi-solid, and solid states of fine-grained soil.

What is the plasticity index (PI) of a soil and what does it indicate?

PI = Liquid Limit − Plastic Limit; it indicates the range of water content over which the soil remains plastic—higher PI means more clayey/plastic soil.

What does the Standard Proctor test determine?

The optimum moisture content (OMC) and maximum dry density (MDD) of a soil at which it achieves maximum compaction for a given compactive effort.

What is the purpose of the Standard Penetration Test (SPT) in soil testing?

To determine the in-situ relative density/consistency and bearing capacity of soil by counting blows (N-value) needed to drive a split-spoon sampler 300 mm into the ground.

State the Coulomb's equation for shear strength of soil.

τ = c + σ tan φ, where c is cohesion, σ is normal stress, and φ is the angle of internal friction.

Differentiate between viscosity and surface tension of a fluid.

Viscosity is a fluid's resistance to shear/flow (internal friction); surface tension is the tensile force per unit length acting on a liquid's free surface due to molecular cohesion.

What is the difference between an ideal fluid and a real fluid?

An ideal fluid has zero viscosity and is incompressible (no shear resistance); a real fluid has viscosity and offers resistance to shear and flow.

State Bernoulli's equation and its components.

p/ρg + v²/2g + z = constant, representing pressure head + velocity (kinetic) head + datum (potential) head along a streamline for an ideal, incompressible, steady flow.

What is the Reynolds number, and what are its limits for laminar and turbulent flow in a pipe?

Re = ρVD/μ (inertia/viscous force ratio). In pipes: laminar for Re < 2000, turbulent for Re > 4000, transitional in between.

What is the continuity equation for incompressible flow?

A₁V₁ = A₂V₂; the discharge (Q) is constant, so velocity increases where the area decreases.

What is the difference between flow irrigation and lift irrigation?

In flow irrigation water flows to the field by gravity from a higher source; in lift irrigation water is raised (lifted) by pumps from a lower source such as a well or river.

Differentiate between perennial irrigation and inundation irrigation.

Perennial irrigation supplies water continuously throughout the crop period via canals from a permanent source; inundation (flood) irrigation supplies water only during floods, with no assured supply.

What is 'drip irrigation' and what is its main advantage?

A micro-irrigation method delivering water drop by drop directly to the plant root zone through pipes/emitters; its main advantage is very high water-use efficiency with minimal losses.

Define 'duty' and 'delta' in irrigation.

Duty is the area (hectares) irrigated per unit discharge (cumec); delta is the total depth of water required by a crop over its base period. Relation: Δ = 8.64 B / D (B in days, D in duty).

What is the difference between a flexible pavement and a rigid pavement in highway engineering?

Flexible pavement (bituminous) transfers load to subgrade through grain-to-grain contact via multiple layers; rigid pavement (cement concrete) resists load by slab flexural strength and spreads it over a wide area.

What is 'camber' in road construction and why is it provided?

Camber is the transverse slope given to the road surface to drain rainwater quickly to the sides, preventing water stagnation and pavement damage.

What is 'superelevation' on a highway?

The transverse raising of the outer edge of the road over the inner edge at a horizontal curve to counteract centrifugal force on moving vehicles.

What is the standard gauge width of Indian Railways Broad Gauge?

1676 mm (1.676 m).

What are the functions of railway sleepers?

To hold rails to correct gauge and alignment, transfer load from rails to ballast, provide a firm and even support, and act as elastic medium between rails and ballast.

What is 'coning of wheels' in railway engineering?

Providing a slope (typically 1 in 20) to the tread of railway wheels so the train can negotiate curves smoothly and stay centred on the track, reducing wear.

What is the permissible limit of turbidity and the desirable pH range for drinking water as per Indian standards?

Turbidity should ideally be < 1 NTU (acceptable up to 5 NTU) and the desirable pH range is 6.5 to 8.5.

Why is chlorine added in water treatment (purpose of chlorination)?

For disinfection—to kill pathogenic bacteria and microorganisms, ensuring the water is safe to drink; residual chlorine also prevents recontamination in the distribution system.

Differentiate between BOD and COD in wastewater treatment.

BOD (Biochemical Oxygen Demand) is the oxygen needed by microbes to biologically decompose organic matter; COD (Chemical Oxygen Demand) is the oxygen needed to chemically oxidize all organic matter—COD is always higher than BOD.

What is the function of a septic tank in waste management?

It provides primary treatment of sewage by allowing solids to settle and undergo anaerobic decomposition, separating sludge and scum while clarified effluent flows out for further disposal.

State the difference between a determinate and an indeterminate structure.

A statically determinate structure can be fully analysed using equations of equilibrium alone; an indeterminate (redundant) structure requires additional compatibility/deformation equations because unknown reactions exceed available equilibrium equations.

What is the degree of static indeterminacy formula for a plane frame?

Ds = 3m + r − 3j (where m = members, r = reactions, j = joints).

Define the 'point of contraflexure' in a beam.

The point along a beam where the bending moment changes sign (from positive to negative or vice versa) and is momentarily zero.

What does the grade M20 of concrete signify?

A concrete with characteristic compressive strength of 20 N/mm² at 28 days on a 150 mm cube (M = mix, 20 = strength in MPa).

What is the water-cement ratio and how does it affect concrete?

It is the ratio of the weight of water to the weight of cement in a mix; a lower w/c ratio increases strength and durability but reduces workability.

What is the purpose of curing concrete?

To maintain adequate moisture and temperature so that cement hydration continues, developing the designed strength and durability and preventing cracking.

What is the initial and final setting time of ordinary Portland cement as per IS specifications?

Initial setting time should not be less than 30 minutes; final setting time should not be more than 600 minutes (10 hours).

Why are steel structures often connected using high-strength friction-grip (HSFG) bolts or welds rather than rivets today?

Because welds and HSFG bolts give stronger, more rigid joints, allow faster fabrication, reduce noise and labour, and provide better fatigue performance than riveting, which is now largely obsolete.

What is the difference between a column and a strut in steel structures?

Both are compression members; a column is a vertical compression member transmitting load to a foundation, while a strut is any compression member (often inclined or horizontal) in a frame or truss.

What is 'slenderness ratio' of a steel compression member and its significance?

It is the ratio of effective length to the least radius of gyration (L/r); a higher slenderness ratio increases the tendency to buckle, reducing the safe load-carrying capacity.