I85PREP
⌘ K
Engineer Civil Engineering study materials
Engineer Civil Engineering study resources

Engineer Civil Engineering practice questions

One question at a time. Build your Engineer Civil Engineering understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Construction Engineering

In a structural steel bolted connection, which condition defines a slip-critical (friction-type) joint as opposed to a bearing-type joint?

  1. The bolts are snug-tight only and load is transferred by shear and bearing on the hole.
  2. The connection relies on welds combined with ordinary bolts sharing the load equally.
  3. The bolts are tightened to a specified pretension and the faying surfaces are prepared so that load is transferred by friction. Correct answer.
  4. The bolts are designed to fail in tension before the plates yield.

Explanation

A slip-critical joint transfers service load through friction generated by clamp force from pretensioned bolts acting on prepared faying surfaces, so slip is prevented at service level. A bearing-type joint permits slip and then carries load through bolt shear and bearing against the hole. The distinction depends on pretension, surface condition, and the design limit state selected.

Question 2Construction Engineering

A concrete mix has a water-cementitious materials ratio of 0.45 by mass and contains 380 kg of cementitious material per cubic metre. What is the mass of water per cubic metre, ignoring water in aggregates?

  1. 209 kg
  2. 190 kg
  3. 152 kg
  4. 171 kg Correct answer.

Explanation

The water-cementitious ratio is the mass of water divided by the mass of cementitious material. Multiplying 0.45 by 380 kg gives 171 kg of water per cubic metre. Aggregates are assumed to be in a saturated surface-dry state, so no adjustment is needed here.

Question 3Construction Engineering

Which piece of equipment is most appropriate for compacting a deep lift of cohesionless granular backfill in a confined trench?

  1. A pneumatic rubber-tired roller
  2. A plate compactor or vibratory plate tamper Correct answer.
  3. A smooth steel-drum vibratory roller
  4. A sheepsfoot roller

Explanation

Confined trench work requires small, maneuverable equipment, and vibratory plates are effective on cohesionless granular soils because vibration induces densification. Large rollers cannot access a narrow trench, and sheepsfoot rollers suit cohesive soils rather than clean granular material.

Question 4Construction Engineering

On a construction site, a crane is lifting a load over a public sidewalk adjacent to the site. Which control most directly addresses the hazard to the public?

  1. Posting warning signs at the site entrance
  2. Providing a covered pedestrian protection structure and rerouting pedestrians clear of the lift zone Correct answer.
  3. Increasing the frequency of crane wire-rope inspections
  4. Requiring the operator to hold a current crane certification

Explanation

Public safety during overhead lifting is controlled by physical separation and overhead protection, such as a covered walkway plus rerouting pedestrians outside the suspended-load zone. Operator certification and inspections address equipment and competency, not exposure of the public beneath the load. Signage alone does not protect people from a dropped load.

Question 5Construction Engineering

In a reinforced concrete beam, why is the development length of a deformed bar specified in design codes?

  1. To ensure the bar can transfer its yield force to the concrete without pullout or splitting Correct answer.
  2. To limit the deflection of the beam under service loads
  3. To ensure the bar can be bent without cracking the surrounding concrete
  4. To control the spacing of stirrups in the shear span

Explanation

Development length is the embedment needed for a bar to reach its design stress through bond without pulling out or splitting the concrete cover. It is a force-transfer requirement, not a deflection or detailing convenience. Bond stress, cover, spacing, and confinement all influence the required length.

Question 6Construction Engineering

A contractor must place a concrete slab on grade in hot weather. Which measure best reduces the risk of plastic shrinkage cracking?

  1. Starting placement at midday when ambient temperature peaks
  2. Using a windbreak and fog spray, and commencing curing immediately after finishing Correct answer.
  3. Adding water at the truck chute to restore slump
  4. Increasing the cement content to accelerate setting

Explanation

Plastic shrinkage cracking occurs when the surface loses moisture faster than bleed water arrives, which hot, windy, dry conditions aggravate. Windbreaks, fogging, and prompt curing reduce evaporation from the fresh surface. Adding water or extra cement increases shrinkage potential and should be avoided.

Question 7Construction Engineering

Which contract delivery method places the design responsibility with the entity that also constructs the project, under a single contract?

  1. Design-bid-build
  2. Construction management at risk
  3. Design-build Correct answer.
  4. Agency construction management

Explanation

In design-build, one entity holds a single contract for both design and construction, giving a single point of responsibility. Design-bid-build separates designer and contractor, and construction management arrangements typically retain the owner's separate design contract.

Question 8Construction Engineering

A soil sample has a natural water content of 18 percent, a void ratio of 0.70, and a specific gravity of solids of 2.70. Which value is closest to the degree of saturation?

  1. 50 percent
  2. 100 percent
  3. 85 percent
  4. 69 percent Correct answer.

Explanation

Degree of saturation equals water content times specific gravity divided by void ratio, expressed as a percentage. With w = 0.18, Gs = 2.70, and e = 0.70, the result is 0.18 × 2.70 / 0.70 = 0.694, about 69 percent. The sample is therefore partially saturated.

Question 9Construction Engineering

A simply supported reinforced concrete beam spans 6 m and carries a uniform factored load of 30 kN/m including self-weight. What is the maximum factored bending moment?

  1. 180 kN·m
  2. 90 kN·m
  3. 270 kN·m
  4. 135 kN·m Correct answer.

Explanation

For a simply supported beam under uniform load, the maximum moment is wL²/8. Substituting 30 kN/m and 6 m gives 30 × 36 / 8 = 135 kN·m at midspan. The support moments are zero for a simple span.

Question 10Construction Engineering

During a standard Proctor compaction test, the dry unit weight is plotted against water content. What does the peak of the resulting curve represent?

  1. The water content at which the soil becomes fully saturated
  2. The field water content required for the soil to be workable by hand
  3. The maximum dry unit weight and its corresponding optimum water content for the applied compactive effort Correct answer.
  4. The water content at which the soil changes from plastic to liquid state

Explanation

The compaction curve peaks at the maximum dry unit weight achievable under the given compactive effort, paired with the optimum water content. Water lubricates particles up to that point; beyond it, water displaces soil and dry density falls. The curve is specific to the energy applied.

Question 11Construction Engineering

A steel column base plate is to be grouted under a column carrying a compressive load. Why is non-shrink grout typically specified rather than an ordinary cement-sand mortar?

  1. Non-shrink grout provides a bond that replaces the need for anchor bolts.
  2. Non-shrink grout expands slightly during curing to ensure full contact between the base plate and the foundation. Correct answer.
  3. Non-shrink grout is used only where the base plate is welded to the anchor rods.
  4. Non-shrink grout has a lower compressive strength, which reduces stress concentration.

Explanation

Non-shrink grout compensates for the shrinkage and settlement that ordinary mortar exhibits, so the base plate bears uniformly on the foundation. Full contact avoids local crushing and uneven load distribution. Anchor bolts remain the means of resisting uplift and shear.

Question 12Construction Engineering

A site's temporary excavation must remain open for several weeks in stiff clay. Which support system is most suitable for a deep, narrow utility excavation where the sides can stand briefly unsupported?

  1. Sloping the sides back at a 1:1 gradient
  2. Trench shields or a trench box with hydraulic struts Correct answer.
  3. Rock anchors grouted into the clay
  4. Soldier piles with timber lagging and walers

Explanation

A trench box provides portable, reusable worker protection in narrow utility trenches and can be advanced as work proceeds. Soldier piles with lagging suit larger open excavations, and sloping requires far more right-of-way than a narrow trench allows. Rock anchors are unnecessary in stiff clay and do not protect workers in a trench.

Question 13Construction Engineering

A concrete pavement is to be constructed with joints at 4.5 m spacing in a slab 200 mm thick. Which statement best explains the function of the transverse contraction joints?

  1. They seal the pavement surface against water infiltration.
  2. They permit the slab to be lifted for subbase inspection.
  3. They allow load transfer between adjacent lanes through dowel bars only.
  4. They create a weakened plane that controls where shrinkage and thermal cracking occur. Correct answer.

Explanation

Contraction joints are sawn or formed to a reduced section so that restrained shrinkage and thermal contraction cracks form at a planned, sealed location. Dowels may transfer load, but that is not the primary purpose of the joint itself. Joint sealing protects the joint but does not define its structural function.

Question 14Construction Engineering

A contractor is planning a tower crane for a high-rise project. Which factor most directly determines the required jib length and load chart selection?

  1. The farthest pick radius and the heaviest load to be lifted at each radius Correct answer.
  2. The color scheme required by the local planning authority
  3. The number of workers in the site welfare facilities
  4. The capacity of the concrete mixer trucks

Explanation

Crane selection is governed by the load chart, which relates capacity to radius. The jib must reach the farthest required pick point, and capacity must exceed the heaviest load at every radius in the lifting plan. Welfare facilities and truck capacity do not govern crane geometry.

Question 15Construction Engineering

A retaining wall is to be backfilled with a free-draining granular material, and a drainage layer with weep holes is provided. Why is this drainage provision important for wall stability?

  1. It eliminates the need for a structural design of the wall stem.
  2. It reduces the unit weight of the backfill, lowering the vertical load on the footing.
  3. It increases the passive resistance of the soil in front of the wall.
  4. It prevents the buildup of pore water pressure, which would otherwise increase lateral thrust on the wall. Correct answer.

Explanation

Water accumulating behind a wall raises pore pressures and adds hydrostatic thrust, which can greatly exceed the drained active earth pressure. A drainage layer and weep holes keep the backfill drained so the wall is designed for drained conditions. Drainage does not remove the need for structural design.

Question 16Construction Engineering

In a hot-rolled steel beam, a hole is drilled in the tension flange for a service connection. How does the hole affect the design of the member?

  1. It has no effect because the flange is in tension and not in compression.
  2. It reduces the net section area, which must be checked against the tension capacity. Correct answer.
  3. It increases the gross section area available to resist bending.
  4. It only affects the shear capacity of the web.

Explanation

A drilled hole removes material from the cross-section, reducing the net area at that location. Where the flange is in tension, the reduced net section must be checked for tensile rupture in addition to the gross-section yielding check. The hole does not add area, and it is remote from the web shear path.

Question 17Construction Engineering

A construction project is delayed by unusually severe weather that meets the contract's force majeure definition. Under a typical standard form, what is the contractor generally entitled to?

  1. Automatic termination of the contract
  2. Neither time nor cost, because weather risk always rests with the contractor
  3. An extension of time, with costs recoverable from the employer in all cases
  4. An extension of time, with costs generally not recoverable unless the contract provides otherwise Correct answer.

Explanation

Force majeure clauses commonly relieve the contractor from liquidated damages by granting an extension of time. Monetary compensation is a separate question and is usually excluded unless the contract expressly provides for it. Termination is a much more drastic remedy and is not automatic.

Question 18Construction Engineering

A slump test is performed on a concrete sample, and the result is 25 mm. Which interpretation is most appropriate for a normal structural concrete?

  1. The mix has failed and must be rejected regardless of its water-cement ratio.
  2. The mix is stiff and may be difficult to place and compact in congested reinforcement. Correct answer.
  3. The slump value indicates the compressive strength directly.
  4. The mix is highly workable and suitable for heavily reinforced sections.

Explanation

A 25 mm slump indicates a stiff, low-workability mix that can be hard to place and compact around congested reinforcement. Slump measures consistency, not strength, and a low value alone is not grounds for rejection. Acceptance depends on the specified slump range and other tests.

Question 19Construction Engineering

A site has a soft clay layer 4 m thick overlying stiff clay. The ground is to be preloaded with a surcharge fill to accelerate consolidation before construction. Which mechanism explains why the surcharge is effective?

  1. The surcharge reduces the thickness of the clay layer.
  2. The surcharge increases the coefficient of permeability of the clay.
  3. The surcharge increases the effective stress in the clay, driving pore water out and accelerating settlement before construction. Correct answer.
  4. The surcharge chemically stabilizes the clay minerals.

Explanation

Preloading raises the total stress in the soft clay, and as excess pore pressures dissipate the effective stress increases, causing consolidation settlement to occur during the surcharge period. Much of the long-term settlement is thus removed before the structure is built. Permeability and layer thickness are essentially unchanged by the fill.

Question 20Construction Engineering

A steel truss member is 8 m long, pinned at both ends about both axes, and is fabricated from a section with a minimum radius of gyration of 40 mm. Which value is closest to its slenderness ratio?

  1. 200 Correct answer.
  2. 320
  3. 150
  4. 100

Explanation

Slenderness ratio is the effective length divided by the radius of gyration. For a pinned-pinned member the effective length equals the actual length, so 8000 mm divided by 40 mm gives 200. This is a high slenderness value and would typically govern compression design.

Question 21Construction Engineering

A concrete mix design specifies a target mean strength above the characteristic strength. Which statement best explains why the target mean is set higher than the specified characteristic value?

  1. To account for the weight of the reinforcement in the element
  2. To ensure the concrete sets faster than the specified time
  3. To allow the contractor to reduce the cement content during hot weather
  4. To compensate for the variability of production so that the required proportion of results falls above the characteristic value Correct answer.

Explanation

Concrete strength varies from batch to batch, so the target mean is set above the characteristic value by a margin related to the standard deviation. This ensures that only a small permitted proportion of test results falls below the characteristic strength. Setting time, cement content, and reinforcement weight are unrelated to this margin.

Question 22Construction Engineering

A deep excavation in a dense sand is supported by a cantilever sheet pile wall. As excavation proceeds, the wall deflects and the adjacent ground settles. Which measure is most effective in reducing ground movements behind the wall?

  1. Installing ground anchors or struts to provide restraint near the top of the wall Correct answer.
  2. Dewatering the sand behind the wall to lower the water table
  3. Increasing the excavation depth in a single pass to speed construction
  4. Removing the passive soil in front of the toe to reduce pressure

Explanation

Cantilever walls deflect most at the top, so adding restraint such as struts or ground anchors near the top reduces deflection and the associated ground settlement. Rapid deep excavation in one pass increases movements, and removing passive soil at the toe reduces stability. Dewatering behind the wall can increase effective stress and settlement.

Question 23Construction Engineering

A reinforced concrete column is subjected to a factored axial load and a small factored moment. Which statement correctly describes the interaction between axial load and moment in the design of the section?

  1. The column is designed for axial load only when the eccentricity is less than the section depth.
  2. The moment capacity increases without limit as the axial load increases.
  3. The moment capacity is independent of the axial load because the two effects are additive.
  4. The axial load and moment must be checked together using an interaction diagram, since axial load affects the section's moment capacity. Correct answer.

Explanation

Axial load changes the strain distribution and hence the available moment capacity, so columns are designed using an interaction diagram relating axial load to moment. Moment capacity rises with moderate axial load and then falls as the section approaches pure compression. Treating the effects as independent is unsafe.

Question 24Construction Engineering

A project uses the critical path method, and the network has a critical path of 40 days. A non-critical activity with 5 days of total float is delayed by 7 days for reasons attributable to the employer. What is the effect on the project completion date?

  1. The completion date is unaffected because the activity is not on the critical path.
  2. The completion date is delayed by 7 days.
  3. The completion date is delayed by 2 days unless the delay is concurrent with another event. Correct answer.
  4. The completion date is delayed by 5 days, equal to the available float.

Explanation

Delay beyond total float consumes the float and then extends the critical path by the excess. Here 7 days of delay against 5 days of float pushes completion by 2 days, subject to concurrency analysis. The activity's non-critical status alone does not make the project immune to delay.

Question 25Construction Engineering

A simply supported prestressed concrete beam is to be designed so that no tensile stress occurs in the concrete at the bottom fibre under full service load. Which statement best describes the required prestress condition?

  1. The tendon must be placed in the compression zone above the neutral axis.
  2. The prestress force must be zero at transfer and increase with applied load.
  3. The prestress must be applied concentrically at the centroid of the section.
  4. The compressive stress from prestress at the bottom fibre must be at least equal to the tensile bending stress produced by the service load. Correct answer.

Explanation

For a no-tension condition at the bottom fibre, the compressive stress induced by prestress must equal or exceed the tensile stress from the service bending moment at that fibre. This usually requires an eccentric tendon below the centroid to generate the needed bottom compression. Prestress does not vary with applied load in this way, and a tendon above the neutral axis would worsen bottom tension.

Question 26Construction Engineering

A concrete batch is specified as grade C30/37. What does the '37' represent in this designation?

  1. The characteristic tensile splitting strength in N/mm² at 28 days
  2. The target mean cube strength in N/mm² at 28 days
  3. The characteristic cylinder strength in N/mm² at 28 days
  4. The characteristic cube strength in N/mm² at 28 days Correct answer.

Explanation

In the European standard designation C30/37, the first number is the characteristic cylinder strength and the second is the characteristic cube strength, both at 28 days and expressed in N/mm². The cube strength is higher because of the shape effect of the test specimen. The target mean strength is deliberately set above the characteristic value to allow for variability.

Question 27Construction Engineering

A contractor is setting out a rectangular building using a total station. To establish a right angle at a corner without relying on the instrument's angle measurement, which field method is most appropriate?

  1. Use the total station's electronic distance measurement to set the diagonal equal to the sum of the two sides
  2. Measure a 3-4-5 triangle using a steel tape along the two sides and the diagonal
  3. Align the instrument with a magnetic compass bearing and turn exactly 90 degrees
  4. Set out the two sides and then check that the diagonals are equal in length Correct answer.

Explanation

For a rectangle, equal diagonals confirm that the corners are right angles, so checking diagonal lengths is a reliable field check independent of angle measurement. The 3-4-5 method also works but requires a tape and is limited to small layouts; the diagonal-equality check scales to full building dimensions. Compass bearings are affected by local magnetic variation and are not precise enough for setting out.

Question 28Construction Engineering

A contractor must dispose of excavated soil classified as non-hazardous. Which documentation is normally required before the soil can be removed from site under a construction waste management plan?

  1. A material safety data sheet for the soil
  2. A permit to work issued by the site manager
  3. A waste transfer note describing the waste and the licensed carrier Correct answer.
  4. A concrete cube test certificate

Explanation

Under waste regulations, non-hazardous excavated soil leaving site must be accompanied by a waste transfer note that describes the waste and identifies a licensed carrier and receiving site. This provides the audit trail required by the waste management plan. Material safety data sheets apply to hazardous substances, and permits to work control high-risk activities rather than waste movement.

Question 29Construction Engineering

A tower crane is to be founded on a reinforced concrete pad. Which soil parameter most directly governs the required base area of the pad for bearing capacity?

  1. The soil's plasticity index
  2. The groundwater pH
  3. The coefficient of active earth pressure
  4. The allowable bearing pressure of the soil Correct answer.

Explanation

The required base area is obtained by dividing the total crane load by the allowable bearing pressure, so this parameter directly controls the pad size. Active earth pressure governs lateral loads on retaining walls, not vertical bearing. Plasticity index and groundwater pH influence other aspects of soil behaviour but do not set the bearing area.

Question 30Construction Engineering

A reinforced concrete wall is to be cast against a previous lift, and the construction joint must transfer shear. Which measure is most appropriate to ensure shear transfer across the joint?

  1. Place a layer of polythene sheeting over the joint to prevent moisture loss
  2. Increase the water content of the second lift to improve workability at the joint
  3. Apply a bonding agent only and leave the joint surface smooth
  4. Roughen the joint surface to expose aggregate and clean it before casting the next lift Correct answer.

Explanation

A roughened, clean surface exposes aggregate and provides mechanical interlock so that shear can be transferred across the construction joint. A smooth surface with only a bonding agent is unreliable for structural shear transfer. Polythene sheeting would act as a debonding layer, and adding water at the joint weakens the concrete.

Question 31Construction Engineering

During excavation for a basement, a contractor encounters a layer of soft organic silt above the design formation level. The engineer requires removal and replacement. Which compaction control test is most appropriate for the granular replacement material?

  1. A vane shear test in the replacement material
  2. A Los Angeles abrasion test on the granular material
  3. A standard Proctor compaction test to establish the maximum dry density and optimum water content Correct answer.
  4. A plate loading test on the finished surface

Explanation

The Proctor test establishes the reference maximum dry density and optimum water content against which field compaction is checked, typically by sand replacement or nuclear density testing. Plate loading tests assess bearing capacity rather than compaction. Vane shear tests are for soft cohesive soils, and the Los Angeles test measures aggregate abrasion resistance.

Question 32Construction Engineering

A simply supported reinforced concrete slab is to be designed for a domestic floor. Which limit state governs the minimum effective depth to control deflection without a detailed calculation?

  1. The serviceability limit state for deflection Correct answer.
  2. The ultimate limit state for flexure
  3. The fire resistance limit state
  4. The ultimate limit state for shear

Explanation

Span-to-effective-depth ratios in codes are a serviceability check intended to keep deflection within acceptable limits without a full deflection calculation. Flexure and shear are ultimate limit states checked separately by reinforcement design. Fire resistance affects cover and member size but does not set the minimum effective depth for deflection control.

Question 33Construction Engineering

A steel beam is to be connected to a column using bolts. The connection is subject to vibration and is to be snug-tightened only. Which bolt type is most appropriate?

  1. A black bolt to a general grade
  2. An ordinary bolt with a washer under the nut only
  3. A high-strength friction grip bolt Correct answer.
  4. A turned and fitted bolt

Explanation

High-strength friction grip bolts are tensioned to a specified preload so that load is transferred by friction between the plies, which resists vibration-induced slip. Ordinary black bolts rely on bearing and are prone to loosening under vibration. Turned and fitted bolts are used for precision fits in machine assemblies rather than structural connections.

Question 34Construction Engineering

A contractor is preparing a method statement for lifting precast panels with a mobile crane. Which factor most directly determines the required crane capacity at the working radius?

  1. The panel colour
  2. The panel surface area
  3. The panel weight alone
  4. The panel weight plus the weight of the lifting accessories Correct answer.

Explanation

The crane must lift the panel plus all lifting accessories, and the capacity must be checked against the load chart at the working radius. Using the panel weight alone underestimates the load. Surface area and colour do not determine the lifted load.

Question 35Construction Engineering

A concrete pavement is to be constructed with dowel bars at transverse joints. What is the primary function of the dowel bars?

  1. To increase the flexural strength of the slab
  2. To anchor the slab to the sub-base
  3. To transfer load across the joint while allowing longitudinal movement Correct answer.
  4. To prevent the slab from contracting

Explanation

Dowel bars are smooth bars that transfer vertical load across a transverse joint while allowing the slab to move longitudinally as it expands and contracts. They do not add flexural strength to the slab. They must be aligned with the direction of movement and are not bonded to both faces.

Question 36Construction Engineering

A deep excavation in soft clay is supported by a propped diaphragm wall. Monitoring shows increasing wall deflection and ground surface settlement. Which immediate action is most appropriate?

  1. Increase the excavation rate to reach formation level quickly
  2. Remove the props to relieve the load on the wall
  3. Reduce the monitoring frequency to avoid alarm
  4. Install additional props or increase prop preload and review the support design Correct answer.

Explanation

Increasing deflection and settlement indicate that the support system is not controlling ground movements, so additional props or higher preload are needed and the design should be reviewed. Accelerating excavation would reduce support and worsen movements. Removing props would be unsafe, and reducing monitoring would hide the problem.

Question 37Construction Engineering

A contractor is to place a large concrete pour in a location where access for ready-mix trucks is limited. Which concrete placement method is most appropriate to maintain continuous supply?

  1. Placing with a crane and skip from a single truck
  2. Pumping from a remote pump station Correct answer.
  3. Hand-placing from wheelbarrows
  4. Spraying with a dry-mix gunite machine

Explanation

Pumping allows concrete to be delivered over a distance and at height, maintaining a continuous supply when truck access is limited. A single truck and skip would not sustain a large pour. Hand-placing is slow and unsuitable for large volumes, and gunite is a sprayed mortar used for linings, not mass concrete placement.

Question 38Construction Engineering

A precast concrete segmental tunnel lining is to be erected. Which factor most directly controls the required jacking force during segment erection?

  1. The friction between the segment and the tail skin and the resistance of the ground Correct answer.
  2. The colour of the segment
  3. The water-cement ratio of the concrete mix
  4. The compressive strength of the concrete only

Explanation

The jacking force must overcome friction between the segment ring and the tail skin and the resistance ahead of the shield. Concrete strength and water-cement ratio affect the material but do not directly set the jacking force. Colour is irrelevant.

Question 39Construction Engineering

A contractor is assessing the risk of chloride-induced corrosion in a reinforced concrete structure near the coast. Which concrete property most directly improves the resistance to chloride ingress?

  1. Lower thermal conductivity
  2. Higher tensile strength
  3. Lower permeability Correct answer.
  4. Higher compressive strength

Explanation

Chloride ions move through the pore structure of concrete, so a lower permeability reduces the rate of ingress and delays the onset of corrosion. Compressive strength correlates with permeability but is not the direct controlling property. Tensile strength and thermal conductivity do not control chloride transport.

Question 40Construction Engineering

A construction project is subject to a liquidated damages clause. The contractor is delayed by an employer-instructed variation that affects the critical path. Which statement best describes the contractor's entitlement?

  1. The contractor is entitled to liquidated damages from the employer
  2. The contractor is entitled to an extension of time but not to any cost
  3. The contractor is entitled to an extension of time and may be relieved of liquidated damages for the varied period Correct answer.
  4. The contractor must accelerate to recover the delay at its own cost

Explanation

An employer-instructed variation that delays the critical path is an employer risk event, so the contractor is entitled to an extension of time and is relieved of liquidated damages for that period. The contractor may also be entitled to cost, but the core entitlement is time. Liquidated damages are payable by the contractor to the employer, not the reverse.

Question 41Geotechnical Engineering

In a standard consolidation test on a saturated clay specimen, which parameter is determined directly from the slope of the void ratio versus logarithm of effective stress curve in the normally consolidated range?

  1. Preconsolidation pressure
  2. Coefficient of consolidation cv
  3. Compression index Cc Correct answer.
  4. Coefficient of secondary compression

Explanation

The compression index Cc is defined as the slope of the e versus log sigma prime curve in the virgin compression range, so it is read directly from the linear normally consolidated portion. The coefficient of consolidation comes from time-settlement data, not the slope of that curve.

Question 42Geotechnical Engineering

A soil sample has a void ratio of 0.75 and the specific gravity of solids is 2.65. What is the dry unit weight, taking the unit weight of water as 9.81 kN/m3?

  1. 14.86 kN/m3 Correct answer.
  2. 25.98 kN/m3
  3. 9.81 kN/m3
  4. 18.52 kN/m3

Explanation

Dry unit weight equals Gs times the unit weight of water divided by one plus the void ratio: 2.65 times 9.81 divided by 1.75, which gives about 14.86 kN/m3. This relationship follows directly from the phase diagram definition of dry density.

Question 43Geotechnical Engineering

According to Terzaghi's bearing capacity theory for a shallow strip footing, which term is set to zero when the footing rests on the ground surface?

  1. The shape factor term
  2. The surcharge term involving the overburden pressure Correct answer.
  3. The cohesion term involving the undrained strength
  4. The unit weight term involving the footing width

Explanation

The surcharge term depends on the overburden pressure at footing level, which vanishes when the footing base is at the ground surface. The cohesion and unit weight terms remain because they depend on soil strength and footing width, not on depth of embedment.

Question 44Geotechnical Engineering

Which in-situ test is most directly suited to estimating the undrained shear strength profile of soft to medium cohesive soils by pushing a slender probe and measuring resistance?

  1. Seismic refraction survey
  2. Standard penetration test
  3. Cone penetration test Correct answer.
  4. Plate load test

Explanation

The cone penetration test continuously measures tip resistance and sleeve friction during penetration, and correlations give undrained shear strength for cohesive soils. The standard penetration test gives blow counts at intervals and is less continuous, while the other methods measure different quantities.

Question 45Geotechnical Engineering

In a cohesionless soil, the factor of safety against piping at the downstream toe of a sheet pile wall is computed as the ratio of which two quantities?

  1. Permeability to the discharge velocity
  2. Critical hydraulic gradient to the existing exit gradient Correct answer.
  3. Effective stress to total stress
  4. Total head to the seepage path length

Explanation

Piping occurs when the upward seepage force reduces effective stress to zero, which happens at the critical hydraulic gradient. The factor of safety is therefore the critical gradient divided by the actual exit gradient at the toe.

Question 46Geotechnical Engineering

A saturated normally consolidated clay has an initial void ratio of 1.10 and a compression index of 0.30. If the vertical effective stress increases from 100 kPa to 200 kPa, what is the approximate primary consolidation settlement of a 4 m thick layer?

  1. 0.156 m Correct answer.
  2. 0.624 m
  3. 0.312 m
  4. 0.078 m

Explanation

Settlement equals the thickness times Cc divided by one plus the initial void ratio, multiplied by the log of the stress ratio. That is 4 times 0.30 divided by 2.10, times log of 2, giving about 0.156 m.

Question 47Geotechnical Engineering

A retaining wall retains dry sand with a unit weight of 18 kN/m3 and an angle of internal friction of 30 degrees. Using Rankine theory, what is the active lateral earth pressure at a depth of 4 m?

  1. 72 kPa
  2. 36 kPa
  3. 24 kPa Correct answer.
  4. 12 kPa

Explanation

The active earth pressure coefficient for a friction angle of 30 degrees is one third, so the pressure at depth is one third times 18 times 4, which equals 24 kPa. Rankine active pressure increases linearly with depth.

Question 48Geotechnical Engineering

A direct shear test on a dry sand gives a cohesion intercept near zero and a friction angle of 32 degrees. If the normal stress at failure is 200 kPa, what is the shear stress at failure?

  1. 170 kPa
  2. 106 kPa
  3. 125 kPa Correct answer.
  4. 200 kPa

Explanation

For a cohesionless soil the failure envelope is shear stress equal to normal stress times the tangent of the friction angle. The tangent of 32 degrees is about 0.625, so 200 times 0.625 gives about 125 kPa.

Question 49Geotechnical Engineering

Which condition best describes the state of a sand at its critical void ratio under sustained shear?

  1. It becomes fully saturated and liquefies
  2. It collapses abruptly with a sudden loss of all confinement
  3. It continues to deform at constant volume and constant shear resistance Correct answer.
  4. It dilates continuously while gaining strength

Explanation

At the critical void ratio, shearing proceeds at constant volume with no further change in shear resistance, defining the critical state. Dilation or contraction occurs only when the soil is on one side of this state.

Question 50Geotechnical Engineering

A clay has a liquid limit of 55 and a plasticity index of 30. Using Casagrande's plasticity chart, how is this soil classified in the Unified Soil Classification System?

  1. Silty clay of low plasticity (CL-ML)
  2. Inorganic silt of high plasticity (MH)
  3. Organic clay of high plasticity (OH)
  4. Inorganic clay of high plasticity (CH) Correct answer.

Explanation

A liquid limit of 55 plots above the A-line, and a plasticity index of 30 places the soil in the high plasticity range above 50. That combination classifies the soil as CH, an inorganic clay of high plasticity.