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IESL Part II Civil study materials
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IESL Part II Civil practice questions

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Question 1Civil Engineering

In reinforced concrete beam design, which parameter most directly governs the balanced failure condition where concrete crushing and steel yielding occur simultaneously?

  1. The ratio of tensile steel area to the effective depth and concrete width relative to the balanced steel ratio Correct answer.
  2. The span-to-depth ratio of the member
  3. The diameter of the shear stirrups
  4. The clear cover to the tension reinforcement

Explanation

Balanced failure is defined by the reinforcement ratio reaching the balanced value, which depends on the steel area relative to b and d together with the material strengths. When the provided ratio equals the balanced ratio, concrete reaches its crushing strain at the same instant the steel reaches yield. Cover, span-to-depth ratio, and stirrup diameter do not set this condition.

Question 2Civil Engineering

A simply supported beam of span 6 m carries a uniformly distributed load of 10 kN/m. What is the maximum bending moment?

  1. 60 kN·m
  2. 90 kN·m
  3. 30 kN·m
  4. 45 kN·m Correct answer.

Explanation

For a simply supported beam under a uniform load, the maximum moment at midspan equals wL²/8. Substituting w = 10 kN/m and L = 6 m gives 10 × 36 / 8 = 45 kN·m. The other values correspond to different formulas or arithmetic slips.

Question 3Civil Engineering

In a triaxial compression test on a saturated clay, the effective stress parameter A at failure is used primarily to estimate which quantity?

  1. The coefficient of earth pressure at rest
  2. The consolidation settlement rate
  3. The pore pressure developed at failure under given stress changes Correct answer.
  4. The permeability of the clay

Explanation

Skempton's pore pressure parameter A relates the change in pore pressure to the change in principal stress difference. At failure, A_f indicates how much excess pore pressure develops, which is essential for effective stress analysis of stability. Permeability and settlement rate are governed by consolidation theory, not by A.

Question 4Civil Engineering

Which test is standard for determining the liquid limit of a fine-grained soil?

  1. Standard penetration test
  2. Proctor compaction test
  3. Casagrande cup or cone penetrometer method Correct answer.
  4. Constant head permeability test

Explanation

The liquid limit is the water content at the boundary between liquid and plastic states, determined by the Casagrande cup or the fall cone penetrometer. These methods measure the water content at a defined shear strength. Compaction, permeability, and penetration tests serve entirely different purposes.

Question 5Civil Engineering

In open channel flow, the Froude number is best described as which ratio?

  1. Inertial force to viscous force
  2. Viscous force to surface tension force
  3. Inertial force to gravitational force Correct answer.
  4. Buoyancy force to gravitational force

Explanation

The Froude number compares inertial forces to gravitational forces and governs whether flow is subcritical, critical, or supercritical. It is defined as V/√(gD) for open channels. The Reynolds number handles viscous effects, and the Weber number handles surface tension.

Question 6Civil Engineering

A trapezoidal channel has a bottom width of 4 m, side slopes of 1:1 (H:V), and a flow depth of 2 m. What is the wetted perimeter?

  1. 6.83 m
  2. 8.00 m
  3. 10.83 m
  4. 9.66 m Correct answer.

Explanation

For a trapezoid, the wetted perimeter equals b + 2y√(1 + z²), where z is the horizontal to vertical side slope. With b = 4 m, y = 2 m, and z = 1, this gives 4 + 2 × 2 × √2 ≈ 4 + 5.66 = 9.66 m. The other values misapply the geometry.

Question 7Civil Engineering

In structural steel design, the nominal shear strength of a web is primarily a function of which quantity?

  1. The plastic section modulus
  2. The torsional constant of the section
  3. The radius of gyration about the weak axis
  4. The web area times the shear yield stress Correct answer.

Explanation

Web shear strength is based on the web area multiplied by the shear yield stress, typically taken as 0.6 of the yield strength, with a reduction for slender webs. The plastic modulus, radius of gyration, and torsional constant govern flexural and buckling behavior rather than web shear capacity.

Question 8Civil Engineering

Which factor of safety concept is applied in geotechnical design to account for uncertainty in soil parameters when using a limit equilibrium slope stability analysis?

  1. A creep coefficient for long-term deformation
  2. A dynamic amplification factor for seismic events
  3. A load factor applied only to live loads
  4. A partial factor applied to the shear strength parameters to define a mobilized strength Correct answer.

Explanation

In slope stability, the factor of safety is commonly defined as the ratio of available shear strength to mobilized shear strength along the slip surface. This is equivalent to applying a partial factor to cohesion and friction. Load factors for live loads, seismic amplification, and creep relate to other design situations.

Question 9Civil Engineering

In the design of a reinforced concrete column, the minimum eccentricity requirement is intended mainly to do which of the following?

  1. Prevent premature buckling of longitudinal bars
  2. Ensure adequate concrete cover for fire resistance
  3. Account for unavoidable construction and loading imperfections in the design moment Correct answer.
  4. Limit the spacing of lateral ties

Explanation

Design codes require a minimum eccentricity to recognize that perfectly axial load cannot be guaranteed in practice. This minimum moment accounts for construction tolerances and load misalignment. Bar buckling, cover, and tie spacing are handled by separate detailing rules.

Question 10Civil Engineering

A soil sample has a void ratio of 0.8 and a specific gravity of solids of 2.65. What is its saturated unit weight? (Take γw = 9.81 kN/m³)

  1. 18.8 kN/m³ Correct answer.
  2. 16.4 kN/m³
  3. 20.1 kN/m³
  4. 22.5 kN/m³

Explanation

The saturated unit weight is γsat = (Gs + e)γw / (1 + e). Substituting Gs = 2.65, e = 0.8 gives (3.45 × 9.81) / 1.8 ≈ 18.8 kN/m³. The other values arise from arithmetic or formula errors.

Question 11Civil Engineering

In a prestressed concrete beam, the primary purpose of using a draped tendon profile is to do which of the following?

  1. Increase the creep coefficient of the concrete
  2. Counteract the bending moment produced by external loads along the span Correct answer.
  3. Eliminate the need for shear reinforcement
  4. Reduce the concrete compressive strength requirement

Explanation

A draped tendon places the prestressing force with varying eccentricity so that its transverse component and moment counteract the external load moment along the span. This improves the balance of stresses and reduces deflection. It does not change concrete strength requirements, remove shear reinforcement, or increase creep.

Question 12Civil Engineering

Which statement correctly describes the purpose of a shear wall in a multi-storey building?

  1. It supports the roof drainage system
  2. It provides thermal insulation to the building envelope
  3. It carries only vertical gravity loads from the floors above
  4. It resists lateral loads by in-plane stiffness and strength Correct answer.

Explanation

Shear walls are vertical structural elements designed primarily to resist lateral loads such as wind and earthquakes through in-plane stiffness and strength. They also carry gravity loads, but that is not their defining purpose. Insulation and drainage are non-structural functions unrelated to shear walls.

Question 13Civil Engineering

In a concrete mix design, a lower water-cement ratio generally leads to which of the following?

  1. Lower strength and higher permeability
  2. Higher strength and lower permeability Correct answer.
  3. Higher porosity and lower strength
  4. No change in strength but higher workability

Explanation

Reducing the water-cement ratio reduces capillary porosity, which increases compressive strength and decreases permeability. Workability may decrease, which is often compensated by admixtures. Higher porosity and permeability come from higher water-cement ratios.

Question 14Civil Engineering

A retaining wall 5 m high retains a cohesionless soil with a unit weight of 18 kN/m³ and an angle of internal friction of 30°. Using Rankine theory and assuming a dry, level backfill, what is the total active thrust per metre length?

  1. 37.5 kN/m
  2. 75 kN/m Correct answer.
  3. 150 kN/m
  4. 225 kN/m

Explanation

Rankine active pressure coefficient is Ka = (1 - sin φ)/(1 + sin φ) = 1/3 for φ = 30°. The total thrust is ½ Ka γ H² = 0.5 × (1/3) × 18 × 25 = 75 kN/m. The other values reflect incorrect coefficients or missing the half factor.

Question 15Civil Engineering

In hydrology, the unit hydrograph of a catchment is defined for which condition?

  1. A rainfall event of unit depth uniformly distributed over the catchment for a specified duration Correct answer.
  2. A rainfall event with a return period of one year
  3. Any rainfall event producing a peak discharge of one cubic metre per second
  4. A storm of unit intensity lasting one hour regardless of catchment area

Explanation

A unit hydrograph represents the direct runoff response to one unit of effective rainfall (commonly 1 cm or 1 mm) applied uniformly over the catchment during a specified duration. It assumes a linear response. It is not defined by intensity, peak discharge, or return period.

Question 16Civil Engineering

Which of the following best explains why a longer duration of loading increases the settlement of a saturated clay foundation?

  1. The permeability of the clay increases with time
  2. The soil skeleton gradually transfers the applied load as pore water drains Correct answer.
  3. The undrained shear strength increases immediately upon loading
  4. The unit weight of the soil decreases with loading

Explanation

In saturated clay, load is initially carried by excess pore pressure. As water drains slowly, the effective stress increases and the soil skeleton compresses, producing consolidation settlement over time. Undrained strength does not increase immediately, permeability does not rise, and unit weight does not decrease.

Question 17Civil Engineering

In reinforced concrete, the purpose of providing development length for a reinforcing bar is to do which of the following?

  1. Reduce the required concrete cover
  2. Prevent corrosion of the reinforcement
  3. Increase the ductility of the concrete matrix
  4. Ensure the bar can transfer its yield force to the surrounding concrete without slipping Correct answer.

Explanation

Development length is the embedded length required for a bar to develop its design force through bond with the concrete. It prevents pull-out before the bar reaches yield. Ductility, cover, and corrosion protection are addressed by other provisions.

Question 18Civil Engineering

A simply supported rectangular beam has a width of 250 mm and an effective depth of 450 mm. If the design moment is 120 kN·m and the concrete grade provides a limiting moment of resistance greater than this value, which check confirms the section is singly reinforced?

  1. Compare the design moment with the limiting moment of resistance for the balanced section Correct answer.
  2. Compare the beam span with the effective depth
  3. Compare the concrete cover with the bar diameter
  4. Compare the shear force with the concrete shear capacity

Explanation

A section is singly reinforced when the applied design moment does not exceed the limiting moment of resistance of a balanced singly reinforced section. If it does, compression reinforcement is needed. Span-to-depth ratio, cover, and shear capacity address different design checks.

Question 19Civil Engineering

In fluid mechanics, Bernoulli's equation along a streamline is valid under which set of assumptions?

  1. Unsteady, compressible, viscous flow
  2. Steady, compressible, turbulent flow with losses
  3. Unsteady, incompressible flow with friction
  4. Steady, incompressible, frictionless flow along a streamline Correct answer.

Explanation

Bernoulli's equation applies to steady, incompressible, frictionless flow along a streamline, expressing conservation of energy among pressure, velocity, and elevation heads. Real flows require an added head-loss term and do not satisfy the strict assumptions.

Question 20Civil Engineering

Which of the following is the primary function of a geotextile used as a separator in a pavement structure?

  1. To provide reinforcement against bending moments in the pavement
  2. To seal the pavement surface against infiltration
  3. To increase the structural stiffness of the asphalt layer
  4. To prevent mixing of the subgrade and granular base while permitting water flow Correct answer.

Explanation

As a separator, a geotextile prevents fine subgrade particles from migrating into the granular base while allowing water to pass. This preserves the drainage and strength of each layer. It does not add asphalt stiffness, resist bending moments, or act as a surface seal.

Question 21Civil Engineering

In a water treatment plant, coagulation and flocculation are employed primarily to do which of the following?

  1. Disinfect pathogenic microorganisms in the water
  2. Destabilize and aggregate fine colloidal particles so they can be removed by sedimentation and filtration Correct answer.
  3. Adjust the pH of the water to neutrality
  4. Remove dissolved gases such as carbon dioxide

Explanation

Coagulation neutralizes the surface charge of colloidal particles, and flocculation causes them to aggregate into larger flocs that settle or are filtered out. Disinfection, gas removal, and pH adjustment are separate treatment processes.

Question 22Civil Engineering

Which structural analysis method is most appropriate for determining the internal forces in a statically indeterminate continuous beam?

  1. The method of sections only
  2. The slope-deflection or moment distribution method Correct answer.
  3. Simple static equilibrium alone
  4. The virtual work method for deflections only

Explanation

Statically indeterminate beams cannot be solved by equilibrium alone; compatibility methods such as slope-deflection, moment distribution, or matrix stiffness analysis are required. Simple equilibrium and the method of sections apply to determinate structures, and virtual work is used for deflections once forces are known.

Question 23Civil Engineering

A clay layer 4 m thick has a coefficient of consolidation of 2.0 m²/year and drains from both the top and bottom. Approximately how long will it take to reach 90% consolidation? (Take T90 ≈ 0.848)

  1. 6.80 years
  2. 3.40 years
  3. 0.85 years Correct answer.
  4. 1.70 years

Explanation

With double drainage, the drainage path H is half the layer thickness, so H = 2 m. Using t = T90 H² / cv = 0.848 × 4 / 2.0 ≈ 1.70 years. Care must be taken with the drainage path; the value 0.85 years corresponds to an arithmetic slip.

Question 24Civil Engineering

In highway geometric design, superelevation is provided on horizontal curves primarily to do which of the following?

  1. Counteract the centrifugal force acting on vehicles Correct answer.
  2. Reduce the vertical grade of the roadway
  3. Increase the stopping sight distance
  4. Improve drainage of the pavement surface only

Explanation

Superelevation banks the roadway so that a component of the vehicle weight helps resist the centrifugal force in a curve, improving safety and comfort at design speed. It is not intended to change sight distance or vertical grade, though adequate drainage must still be maintained.

Question 25Civil Engineering

In a cantilever retaining wall, the stability against overturning is checked by comparing which quantities?

  1. The passive resistance with the active pressure
  2. The resisting moment about the toe with the overturning moment from lateral earth pressure Correct answer.
  3. The base width with the wall height
  4. The total vertical load with the total lateral load

Explanation

Overturning stability is assessed by taking moments about the toe: the resisting moment from the wall and soil weight must exceed the overturning moment from lateral earth thrust by an adequate factor. Comparing loads directly or dimensions alone does not constitute the overturning check.

Question 26Civil Engineering

A concrete cube specimen is tested in compression and the failure surface is found to pass mainly through the mortar and the interfacial transition zone rather than through the coarse aggregate particles. Which conclusion is most consistent with this observation?

  1. The specimen failed in tension rather than compression
  2. The interfacial transition zone is the weakest link in the composite Correct answer.
  3. The aggregate is weaker than the mortar matrix
  4. The water-cement ratio of the mix was unusually low

Explanation

In normal-strength concrete the interfacial transition zone between paste and aggregate is the weakest component, so cracks initiate and propagate along it. A failure surface that avoids the aggregate particles therefore indicates that the bond zone, not the aggregate itself, governed failure. Low water-cement ratio would strengthen both matrix and bond, and a compressive test failure still involves internal tensile cracking.

Question 27Civil Engineering

A soil is classified as well graded in a sieve analysis report. Which grading curve characteristic supports this classification?

  1. A curve that plots entirely below the 50 percent passing line
  2. A curve with a high uniformity coefficient and a coefficient of curvature between 1 and 3 Correct answer.
  3. A nearly vertical curve over most of the particle-size range
  4. A curve confined to a narrow band of sieve sizes

Explanation

A well-graded soil contains a wide spread of particle sizes, giving a high uniformity coefficient (Cu) together with a coefficient of curvature (Cc) between about 1 and 3. The smooth, broadly spread curve indicates that intermediate sizes are present to fill voids between larger particles.

Question 28Civil Engineering

A rectangular channel carries flow at a Froude number of 0.4. What does this value indicate about the flow state?

  1. The flow is rapidly varied and the channel slope must be steep
  2. The flow is subcritical and disturbances can travel upstream Correct answer.
  3. The flow is supercritical and disturbances travel only downstream
  4. The flow is critical and the specific energy is at a minimum

Explanation

The Froude number compares inertial forces with gravity forces in free-surface flow. A value below 1 means the flow is subcritical, so wave celerity exceeds flow velocity and disturbances can propagate upstream. Critical flow corresponds to a Froude number of exactly 1.

Question 29Civil Engineering

A simply supported beam of span 6 m carries a uniformly distributed load of 10 kN/m over its entire length. What is the maximum bending moment?

  1. 90 kN·m
  2. 45 kN·m Correct answer.
  3. 30 kN·m
  4. 60 kN·m

Explanation

For a simply supported beam with a uniformly distributed load w over span L, the maximum moment is wL²/8. Substituting 10 kN/m and 6 m gives 10 × 36 / 8 = 45 kN·m at midspan.

Question 30Civil Engineering

In limit state design of a reinforced concrete beam, the balanced section condition is defined by which occurrence at ultimate load?

  1. The neutral axis lies at the mid-depth of the section
  2. Concrete reaches its design compressive strain exactly when the tension steel reaches its yield strain Correct answer.
  3. The tension steel ruptures before the concrete crushes
  4. The section carries no shear reinforcement requirement

Explanation

A balanced section is one in which the concrete crushing strain and the steel yield strain are reached simultaneously at the ultimate limit state. Sections with less tension steel are under-reinforced and show ductile behaviour, while over-reinforced sections fail by concrete crushing before steel yields.

Question 31Civil Engineering

A steel column is classified as a slender member in compression. Which phenomenon most directly governs its design strength?

  1. Yielding of the gross cross-section
  2. Bearing failure at the base plate
  3. Local buckling of the flange plate only
  4. Overall flexural buckling about the weak axis Correct answer.

Explanation

Slender compression members fail by elastic or inelastic buckling at a stress below the yield strength. The buckling load depends on the effective length and the least radius of gyration, so the weak axis normally governs. Local buckling and end bearing are checked separately but do not define overall slenderness behaviour.

Question 32Civil Engineering

A catchment of 50 km² receives 100 mm of rainfall in a storm. If the runoff coefficient is 0.6 and losses are ignored elsewhere, what is the total direct runoff volume?

  1. 5.0 million m³
  2. 1.0 million m³
  3. 6.0 million m³
  4. 3.0 million m³ Correct answer.

Explanation

Direct runoff depth equals the runoff coefficient times rainfall, giving 0.6 × 100 mm = 60 mm. Multiplying by the catchment area of 50 km² (50 × 10⁶ m²) gives 0.060 m × 50 × 10⁶ m² = 3.0 × 10⁶ m³.

Question 33Civil Engineering

In a rapid sand filter used for water treatment, backwashing is carried out primarily to achieve which outcome?

  1. Remove accumulated solids and restore the filter bed porosity Correct answer.
  2. Disinfect the filter media with residual chlorine
  3. Precipitate dissolved metals onto the sand grains
  4. Increase the filtration rate by coarsening the media

Explanation

Backwashing fluidises the filter bed so that trapped solids and biological growth are flushed out, restoring head loss and run time. The wash is normally followed by a short filter-to-waste period before returning to service. Backwashing is a physical cleaning step, not a disinfection or chemical treatment step.

Question 34Civil Engineering

A horizontal curve on a rural highway has a radius of 200 m and a design speed of 80 km/h. The superelevation is limited by site constraints. Which statement best describes the design consequence of the radius being reduced while the design speed is held constant?

  1. The side friction factor remains unchanged because it depends only on the pavement type
  2. The curve becomes safer because drivers reduce their speed automatically
  3. The required superelevation and side friction demand both increase Correct answer.
  4. The required superelevation decreases because the curve is shorter

Explanation

On a horizontal curve the centripetal demand is balanced by superelevation and side friction, so a smaller radius raises the total lateral demand e + f. If superelevation is capped, a greater share must come from side friction, which may exceed the allowable value. This is why minimum radii are tabulated for each design speed.

Question 35Civil Engineering

In a triaxial compression test, a saturated normally consolidated clay sample is sheared slowly with drainage permitted. Which strength parameter is measured?

  1. Effective stress cohesion and friction angle Correct answer.
  2. Elastic modulus and Poisson's ratio
  3. Unconfined compressive strength only
  4. Undrained shear strength with total stress parameters

Explanation

A slow drained triaxial test allows pore pressures to dissipate, so the measured strength is expressed in terms of effective stress. Normally consolidated clay typically shows negligible effective cohesion and a friction angle governed by particle interlocking and rearrangement.

Question 36Civil Engineering

A retaining structure is to be designed for a site underlain by soft clay. Which lateral earth pressure condition is most critical for the design of the wall stem in the short term?

  1. Active pressure computed with effective stress parameters
  2. At-rest pressure computed with the coefficient of earth pressure at rest
  3. Active pressure computed with undrained shear strength Correct answer.
  4. Passive pressure mobilised in front of the wall

Explanation

In the short term, soft clay behaves undrained and the lateral pressure is governed by total stress with undrained shear strength. Using effective stress active pressure would underestimate the short-term load because excess pore pressures are not accounted for. Passive resistance in front of the wall is a resisting force, not a loading case for the stem.

Question 37Civil Engineering

In the design of a cantilever slab in a reinforced concrete building, the main reinforcement is placed in which direction?

  1. Perpendicular to the supporting edge, at the bottom face
  2. Parallel to the supporting edge, at the bottom face
  3. Parallel to the supporting edge, to resist shrinkage
  4. Perpendicular to the supporting edge, at the top face Correct answer.

Explanation

A cantilever slab bends with tension at the top surface, so the main bars run perpendicular to the support and are placed near the top. Distribution steel is placed parallel to the support to control cracking and spread local loads. Placing the main steel at the bottom would leave the tension zone unreinforced.

Question 38Civil Engineering

Which statement best describes the role of a stiffener in a plate girder web?

  1. It replaces the need for web shear reinforcement
  2. It transfers the entire shear force to the supports
  3. It prevents local buckling of the web by reducing its unstiffened panel size Correct answer.
  4. It increases the plastic section modulus of the girder

Explanation

Stiffeners divide the web into smaller panels, raising the elastic buckling stress of the plate. Intermediate transverse stiffeners control web buckling under shear, while bearing stiffeners carry concentrated loads. They do not increase the section modulus or carry the full shear force themselves.

Question 39Civil Engineering

A pump delivers water through a pipeline at a rate of 0.05 m³/s. The pipe diameter is 200 mm. What is the average flow velocity?

  1. 3.18 m/s
  2. 1.59 m/s Correct answer.
  3. 0.40 m/s
  4. 0.80 m/s

Explanation

The cross-sectional area of a 200 mm pipe is π × 0.2² / 4 = 0.0314 m². Dividing the discharge of 0.05 m³/s by this area gives approximately 1.59 m/s.

Question 40Civil Engineering

A concrete mix is specified with a target mean strength higher than the characteristic strength. What is the main reason for this target mean?

  1. To ensure the mix achieves a higher modulus of elasticity
  2. To compensate for the self-weight of the structure
  3. To allow for variability in materials and production so that few results fall below the characteristic value Correct answer.
  4. To reduce the required cement content in the mix

Explanation

Concrete strength varies from batch to batch, so the target mean is set above the characteristic strength by a margin related to the standard deviation. This margin ensures that only a small permitted proportion of test results falls below the characteristic value.

Question 41Civil Engineering

A sample of sand has a porosity of 0.40. What is its void ratio?

  1. 1.50
  2. 0.67 Correct answer.
  3. 0.60
  4. 0.40

Explanation

Void ratio and porosity are related by e = n / (1 − n). Substituting n = 0.40 gives e = 0.40 / 0.60 = 0.67. Void ratio can exceed porosity because it is expressed relative to the volume of solids.

Question 42Civil Engineering

In a two-hinged parabolic arch carrying a uniformly distributed load over its entire span, which internal force is essentially zero throughout the arch axis?

  1. Axial thrust
  2. Horizontal thrust at the supports
  3. Bending moment Correct answer.
  4. Shear force at the crown only

Explanation

A parabolic arch subjected to a uniformly distributed load over its full span follows the funicular shape of that load, so the line of thrust coincides with the arch axis. Under this condition the arch carries the load almost entirely by axial compression, with negligible bending moment. Horizontal thrust is present and is a key design force.

Question 43Civil Engineering

Which of the following is the most appropriate primary purpose of compaction of a soil fill in a road embankment?

  1. To change the plasticity index of the soil
  2. To reduce void ratio and increase shear strength and stiffness Correct answer.
  3. To lower the groundwater table beneath the embankment
  4. To increase the permeability of the fill

Explanation

Compaction expels air from the soil, reducing void ratio and raising dry density. This increases shear strength and stiffness and reduces future settlement under traffic and embankment loads. Compaction does not alter the plasticity index, which is a property of the clay minerals.

Question 44Civil Engineering

A reinforced concrete beam is subjected to a design shear force that exceeds the concrete shear capacity. Which action is most appropriate?

  1. Reduce the concrete grade
  2. Increase the beam depth only
  3. Increase the span of the beam
  4. Provide shear reinforcement in the form of stirrups Correct answer.

Explanation

When the applied shear exceeds the concrete contribution, vertical stirrups or inclined links are provided to carry the excess shear and control diagonal cracking. The shear reinforcement is designed so that the total capacity, concrete plus steel, exceeds the design shear force.

Question 45Civil Engineering

In a sedimentation tank used for water treatment, the overflow rate is used as a design parameter. What does the overflow rate represent?

  1. The depth of the tank divided by the detention time
  2. The volumetric flow divided by the plan area of the tank Correct answer.
  3. The head loss across the outlet weir
  4. The velocity of the settled sludge along the tank floor

Explanation

Overflow rate, or surface loading rate, equals the flow divided by the tank plan area and has units of velocity. Particles with a settling velocity greater than the overflow rate are theoretically removed in an ideal horizontal-flow basin. It is used to size the settling area for a required removal performance.

Question 46Civil Engineering

In a prestressed concrete member, which loss of prestress occurs immediately at transfer due to the shortening of the concrete?

  1. Relaxation of steel
  2. Creep of concrete
  3. Shrinkage of concrete
  4. Elastic shortening Correct answer.

Explanation

When the prestressing force is transferred to the concrete, the member shortens elastically and the tendon shortens with it, producing an immediate loss. Creep, shrinkage and steel relaxation are time-dependent losses that develop over the life of the member.

Question 47Civil Engineering

A slope in a stiff clay is analysed using a total stress method with a factor of safety of 1.3. Which statement best describes the basis of this factor of safety?

  1. It is the ratio of the driving moment to the resisting moment, which must be less than one
  2. It is the ratio of the seepage force to the submerged weight of the soil
  3. It is the ratio of the horizontal to vertical effective stress in the slope
  4. It is the ratio of the available undrained shear strength to the mobilised shear stress along the trial slip surface Correct answer.

Explanation

In total stress slope stability analysis, the factor of safety is defined as the available undrained shear strength divided by the shear stress required for equilibrium along the assumed slip surface. A value greater than one indicates an acceptable margin. The analysis is performed for the critical slip circle giving the lowest factor.

Question 48Civil Engineering

A concrete structure is exposed to seawater and freeze-thaw cycles. Which durability measure is most directly effective in resisting freeze-thaw damage?

  1. Entraining a controlled volume of air voids in the paste Correct answer.
  2. Using a higher water-cement ratio to improve workability
  3. Applying a bituminous coating to all surfaces
  4. Increasing the cement content and reducing the aggregate size

Explanation

Air entrainment creates a network of small, closely spaced voids that relieve hydraulic pressure as water freezes in the paste. This greatly improves freeze-thaw resistance. A higher water-cement ratio increases permeability and freezable water, making damage more likely.

Question 49Civil Engineering

A simply supported beam has a span of 8 m and carries a central point load of 40 kN. What is the maximum deflection if EI is 20,000 kN·m²?

  1. 0.053 m
  2. 0.013 m
  3. 0.107 m
  4. 0.021 m Correct answer.

Explanation

For a central point load P on a simply supported span L, the maximum deflection occurs at midspan and is PL³/(48EI). Substituting the stated values gives 40 × 8³ / (48 × 20,000) = 20,480 / 960,000 ≈ 0.0213 m, which rounds to 0.021 m.

Question 50Civil Engineering

In a water distribution network, a pipe is described as a dead-end main. What is its principal hydraulic characteristic?

  1. Flow occurs in one direction only and the downstream end has no alternative supply path Correct answer.
  2. The pipe is designed to carry only fire flow
  3. Flow can travel in either direction depending on demand
  4. The pipe operates under negative pressure at all times

Explanation

A dead-end main terminates in the network, so water can only reach consumers along a single path. This makes the downstream end vulnerable to stagnation and to loss of supply if the main is shut off. Looped networks provide alternative paths and better reliability.