GPSC Civil Engineering (Combine Exam) Paper Solution (03-05-26) – Page 1

1) Consider the following statements about irrigation efficiencies:

1. Water conveyance efficiency accounts for seepage and evaporation losses in canals.
2. Water application efficiency is the ratio of water stored in the root zone to water delivered to the field.
3. Overall project efficiency = water conveyance efficiency × water application efficiency × water storage efficiency.
4. Consumptive use efficiency is the ratio of consumptive use water to net water depleted from the root zone.

Which of the above statements are correct?

1. 1 and 2 only
2. 1, 2 and 3 only
3. 1, 2 and 4 only
4. 1, 2, 3 and 4

2) In the context of seepage through earthen dams, consider the following statements:

1. Phreatic line (seepage line) is the top flow line along which pressure is atmospheric.
2. For a homogeneous earthen dam on an impervious foundation, Dupuit’s parabola approximates the phreatic line.
3. A filter drain (toe drain) at the downstream end raises the phreatic line and increases seepage.
4. The flow net method can be used to estimate seepage quantity: q = k × H × (Nf/Nd).

Which of the above statements are correct?

1. 1 and 2 only
2. 1, 2 and 4 only
3. 2 and 4 only
4. 1, 2, 3 and 4

3) A channel of bed slope 0.0009 carries a discharge of 30 m³/sec when the depth of flow is 1 m. Using Manning’s formula, what is the discharge carried by an exactly similar channel at the same depth of flow if the slope is 0.0001?

1. 10 m³/sec
2. 15 m³/sec
3. 60 m³/sec
4. 90 m³/sec

4) Which of the following statements about Precast and Prefabricated Concrete Technology is/are incorrect?

1. In pre-tensioned precast elements, the prestress transfer (bond) causes the ends of the element to ‘hog’ (camber upward) due to the eccentric prestress force acting above the centroidal axis.
2. ‘Fly Ash Bricks’ manufactured under steam curing (autoclave at 10-16 bar, 150-200°C) achieve strength through pozzolanic reaction between fly ash and Ca(OH)2 from quicklime.
3. The ‘Sandwich Panel’ used in prefabricated construction consists of two thin facings (concrete, steel or FRP) bonded to a low-density insulating core (EPS, PU foam); structural loads are carried by the facings.
4. Large Panel System (LPS) buildings use floor-to-ceiling precast wall panels; the joints between panels are the most critical structural element requiring careful design for shear, tension and compression transfer.

5) Consider the design of a canal drop (fall) structure. Which of the following statements is/are correct?

1. A trapezoidal notch fall maintains a constant Froude number upstream regardless of discharge variation.
2. A sarda type fall is a small drop type fall.
3. The cistern of a fall is designed to contain the hydraulic jump for energy dissipation.
4. A vertical drop fall is suitable for drops up to 1.5 m in small canals.

Which of the above statements are correct?

1. 2 and 3 only
2. 3 and 4 only
3. 1, 2 and 3 only
4. 2, 3 and 4 only

6) Which of the following statements about Timber as a building material is/are incorrect?

1. ‘Kiln Seasoning’ reduces moisture content to the desired level (8-12% for furniture, 15-18% for structural work) more quickly and uniformly than air seasoning, but requires fuel/energy.
2. As per IS 883:1994, stress grades for structural timber are assigned based on permissible bending stress.
3. The ‘Creosote oil’ treatment (pressure impregnation) is the most effective preservation method for timber in severe exposure conditions (ground contact, marine use).
4. The ‘Modulus of Rupture’ (MOR) of timber is always higher than its ‘Modulus of Elasticity’ (MOE) in bending because MOR is a measure of ultimate strength while MOE measures stiffness.

7) Consider the following statements about types of glass used in buildings:

1. Tempered (toughened) glass is approximately 4-5 times stronger than ordinary annealed glass in bending and when it breaks, it shatters into small, sharp edged fragments with very high injury risk.
2. Laminated safety glass consists of two or more glass plies bonded with a PVB (polyvinyl butyral) interlayer; when broken, fragments adhere to the interlayer, preventing scatter.
3. ‘Low-E’ (Low Emissivity) glass has a thin metallic oxide coating that reflects long-wave infrared radiation, reducing heat transfer while allowing visible light transmission.
4. Borosilicate glass (e.g., Pyrex) has a higher coefficient of thermal expansion than soda-lime glass, making it more suitable for thermal shock applications.

Which of the above statements are correct?

1. 1, 2 and 3 only
2. 1 and 2 only
3. 2 and 3 only
4. 1, 2, 3 and 4

8) Consider the following statements about burnt clay bricks as per IS 1077:1992:

1. First-class bricks (Class 35) must have a minimum compressive strength of 25 N/mm² and water absorption not exceeding 25% of their dry weight after 24-hour immersion.
2. The ‘Efflorescence’ test on bricks assesses the presence of soluble salts; a rating of ‘Moderate’ means a thin deposit covering more than 50% of the exposed area.
3. The standard size of a modular brick in India is 190 x 90 x 90 mm (length x width x height); with a 10 mm mortar joint, the coursing dimension becomes 200 × 100 × 100 mm.
4. Bricks with Initial Rate of Absorption (IRA) exceeding 2 kg/m²/min should be pre-wetted before laying to prevent mortar dehydration and loss of bond strength.

Which of the above statements are correct?

1. 1 and 3 only
2. 3 and 4 only
3. 1, 2 and 3 only
4. 1, 2, 3 and 4

9) Regarding well hydraulics and Theis equation, consider the following statements:

1. The Theis method is applicable to unsteady (transient) flow in a confined aquifer with uniform properties.
2. The Cooper-Jacob simplification of the Theis equation is valid when the well function argument u < 0.05.
3. Specific capacity of a well decreases with increasing pumping duration due to well losses.
4. The radius of influence of a well always reaches a finite boundary in a confined aquifer.

Which of the above statements are correct?

1. 1 and 2 only
2. 1, 2 and 3 only
3. 2 and 4 only
4. 1, 2, 3 and 4

10) Which of the following statements about Lime and its classifications as per IS 712:1984 is/are incorrect?

1. Class C (Fat/Quicklime) – CaO only – does set under water; it does not require CO₂, from air for carbonation hardening.
2. Class B (Hydraulic Lime) – contains CaO + calcium silicates (C₂S) – sets both in air and under water due to hydraulic compounds.
3. Class A (Eminently Hydraulic Lime) has the highest hydraulic index (ratio of silica + alumina + iron oxide to CaO) and can be used as a substitute for cement in some applications.
4. The ‘Pozzolanicity’ of fly ash depends on its reactive SiO₂ + Al₂O₃ content; a fly ash with > 70% (SiO₂ + Al₂O₃ + Fe₂O₃) qualifies as Class F (low-calcium) fly ash as per IS 3812.