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BEM PCE Civil & Structural practice questions

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Question 1Civil Engineering

In reinforced concrete design, which parameter most directly governs the ductility of a section at ultimate limit state?

  1. The nominal cover to the outermost bar
  2. The characteristic cylinder strength of the concrete
  3. The span-to-effective-depth ratio of the member
  4. The tensile reinforcement ratio relative to the balanced ratio Correct answer.

Explanation

Ductility at the ultimate limit state is controlled mainly by how far the tensile steel ratio sits below the balanced ratio, since under-reinforced sections yield before concrete crushing and give warning of failure. Concrete strength and cover influence capacity and durability but do not by themselves define the failure mode.

Question 2Civil Engineering

A simply supported beam spans 6 m and carries a uniformly distributed ultimate load of 30 kN/m. What is the maximum design bending moment?

  1. 180 kNm
  2. 135 kNm Correct answer.
  3. 90 kNm
  4. 270 kNm

Explanation

For a simply supported span under uniform load the maximum moment is wL²/8, giving 30 × 36 / 8 = 135 kNm. The other values correspond to different support or load assumptions and do not match this configuration.

Question 3Civil Engineering

Which statement correctly describes the purpose of nominal cover in a reinforced concrete member exposed to a moderate environment?

  1. It limits the concrete strain at the ultimate limit state
  2. It provides the lever arm required for shear reinforcement
  3. It fixes the position of the compression zone in a doubly reinforced section
  4. It protects the reinforcement from corrosion and ensures adequate bond and fire resistance Correct answer.

Explanation

Nominal cover is specified to keep the environment away from the steel, so corrosion initiation is delayed and bond and fire performance are maintained. It is a durability-driven dimension rather than a structural analysis parameter.

Question 4Civil Engineering

In structural steel design, what does the classification of a cross-section as Class 1 (plastic) mean?

  1. The section can develop its plastic moment and rotate sufficiently to allow plastic analysis Correct answer.
  2. The section fails by local buckling before reaching the yield moment
  3. The section is limited to elastic design because of its high width-to-thickness ratio
  4. The section reaches yield only at the extreme fibre without any rotation capacity

Explanation

A Class 1 section can form a plastic hinge and rotate enough for redistribution of moments, which is what allows plastic global analysis. Classes 2, 3 and 4 progressively lose moment capacity or rotation capacity because of local buckling.

Question 5Civil Engineering

Which of the following best defines the characteristic strength of concrete used in design?

  1. The strength at which the stress-strain curve becomes perfectly plastic
  2. The minimum strength permitted for any structural element
  3. The average strength of cubes tested at 28 days
  4. The strength below which 5% of test results are expected to fall Correct answer.

Explanation

Characteristic strength is a statistical fractile, conventionally the value below which 5% of the population is expected to lie. Design values are then derived by dividing by a partial factor of safety.

Question 6Civil Engineering

A cantilever of length 2.5 m carries a point load of 40 kN at its free end. What is the design bending moment at the fixed support?

  1. 160 kNm
  2. 50 kNm
  3. 16 kNm
  4. 100 kNm Correct answer.

Explanation

For a cantilever with an end point load the fixed-end moment is P × L, giving 40 × 2.5 = 100 kNm. The other values arise from dividing or multiplying incorrectly rather than using the lever arm to the support.

Question 7Civil Engineering

Which phenomenon is primarily responsible for the reduced shear capacity of a deep concrete beam compared with predictions from slender beam theory?

  1. Creep of the concrete under sustained load
  2. Arch action transferring load directly to the supports Correct answer.
  3. Strain hardening of the longitudinal reinforcement
  4. Excessive deflection reducing the effective span

Explanation

In deep beams the load path shortens through arch action, so a significant share of the load reaches the supports directly and conventional beam shear theory overestimates or misrepresents capacity. Design codes therefore require alternative strut-and-tie or empirical approaches for such members.

Question 8Civil Engineering

What is the main function of shear studs welded to the top flange of a composite steel beam?

  1. To provide fire protection to the steel section
  2. To transfer longitudinal shear between the steel section and the concrete slab Correct answer.
  3. To prevent lateral torsional buckling of the bottom flange
  4. To reduce the self-weight of the concrete slab

Explanation

Shear connectors ensure composite action by transferring longitudinal interface shear, so the slab and beam act together and the flexural capacity is increased. They do not provide lateral restraint or fire protection.

Question 9Civil Engineering

A reinforced concrete column is subjected to a factored axial load of 2000 kN and a factored moment of 150 kNm about one axis. Which design check is most appropriate?

  1. A shear friction check at the column base
  2. A biaxial bending interaction check using the applied moment on both axes
  3. A pure axial compression check ignoring the moment
  4. A uniaxial column interaction diagram check using the axial load and the applied moment Correct answer.

Explanation

When an axial load and a moment about one principal axis act together, the section is verified against a uniaxial interaction diagram relating axial resistance to moment resistance. Ignoring the moment would be unsafe.

Question 10Civil Engineering

In a simply supported steel beam, which action most commonly governs the design of the web at the support region?

  1. Fatigue from repeated thermal movement
  2. Torsion induced by eccentric loading
  3. Shear force combined with local web bearing and buckling Correct answer.
  4. Bending moment causing yielding of the flange

Explanation

Near supports the shear force is highest, so the web must be checked for shear resistance and for local bearing and buckling where concentrated reactions are applied. Flexural yielding is governed at midspan where moment peaks.

Question 11Civil Engineering

A retaining wall retains 4 m of soil with a unit weight of 18 kN/m³ and an active earth pressure coefficient of 0.33. Neglecting surcharge, what is the total active thrust per metre length?

  1. 95.0 kN/m
  2. 190.0 kN/m
  3. 47.5 kN/m Correct answer.
  4. 23.8 kN/m

Explanation

The lateral pressure increases linearly to a base value of K × γ × H = 0.33 × 18 × 4 = 23.76 kPa, so the triangular thrust is half the base pressure times height, giving about 47.5 kN/m. Forgetting the triangular distribution doubles the answer.

Question 12Civil Engineering

Which statement about the design of a pad footing for a concentrically loaded column is correct?

  1. Soil bearing pressure is assumed uniform regardless of footing rigidity
  2. Punching shear is checked on a perimeter at a defined distance from the column face Correct answer.
  3. The footing thickness may be reduced until the concrete alone resists all shear
  4. Bending reinforcement is required only in the direction of the longer side

Explanation

Punching shear is verified around a control perimeter located a specified distance from the loaded area, reflecting the critical failure surface. Reinforcement is needed in both directions to resist the bending induced by upward soil pressure.

Question 13Civil Engineering

What is the primary reason for providing a nominal amount of longitudinal reinforcement in a concrete column even when the applied load is small?

  1. To resist the full design axial load without relying on concrete
  2. To reduce the amount of transverse reinforcement required
  3. To control cracking, provide ductility and resist accidental moments Correct answer.
  4. To increase the concrete's modulus of elasticity

Explanation

Minimum longitudinal steel controls cracking, provides ductility and gives reserve capacity for accidental eccentricity and moments not captured in the analysis. It is not intended to carry the entire axial load.

Question 14Civil Engineering

In a prestressed concrete beam, why is the tendon profile often draped or parabolic rather than straight?

  1. To allow the use of lower-strength concrete
  2. To match the bending moment diagram and control both stresses and deflection along the span Correct answer.
  3. To eliminate the need for shear reinforcement
  4. To reduce the prestressing force required at transfer

Explanation

A draped or parabolic tendon follows the bending moment diagram, so the eccentricity provides beneficial counter-moment where it is needed and controls stresses and camber along the span. It also produces a vertical component that assists shear resistance.

Question 15Civil Engineering

Which factor most directly increases the lateral torsional buckling resistance of an unrestrained steel beam?

  1. Increasing the torsional constant of the cross-section Correct answer.
  2. Increasing the span between lateral restraints
  3. Applying the load at the bottom flange
  4. Reducing the yield strength of the steel

Explanation

Lateral torsional buckling resistance depends on torsional and warping stiffness, so a larger torsional constant raises the buckling moment. Shortening the unrestrained length also helps, whereas increasing it reduces resistance.

Question 16Civil Engineering

A soil sample has a moisture content of 20% and a dry unit weight of 16 kN/m³. Taking the unit weight of water as 10 kN/m³, what is the bulk unit weight?

  1. 18.0 kN/m³
  2. 17.6 kN/m³
  3. 19.2 kN/m³ Correct answer.
  4. 20.0 kN/m³

Explanation

Bulk unit weight equals dry unit weight multiplied by (1 + moisture content), giving 16 × 1.20 = 19.2 kN/m³. The water unit weight is not needed for this calculation.

Question 17Civil Engineering

Which statement correctly describes the purpose of a movement joint in a long concrete frame?

  1. To accommodate thermal and shrinkage movement without inducing excessive restraint forces Correct answer.
  2. To increase the load-carrying capacity of the slab
  3. To provide a waterproof barrier at the slab edge
  4. To allow the reinforcement to be lapped more easily

Explanation

Movement joints release restraint so that thermal and shrinkage strains do not generate cracking or large forces in the structure. They are a serviceability provision rather than a strength measure.

Question 18Civil Engineering

In the design of a bolted steel connection, what does the term 'slip-critical' refer to?

  1. The bolts are permitted to slip into bearing at the ultimate limit state
  2. The connection is designed so that no slip occurs at the serviceability limit state Correct answer.
  3. The connection relies on welding rather than bolts
  4. The bolts are preloaded to less than half their proof load

Explanation

Slip-critical connections are preloaded so that friction between the plies prevents any relative movement under service loads. Bearing-type connections, by contrast, may slip into bearing before reaching their ultimate capacity.

Question 19Civil Engineering

A reinforced concrete slab is designed as simply supported with a span of 4 m and a total ultimate load of 12 kN/m². What is the maximum design moment per metre width?

  1. 48 kNm/m
  2. 24 kNm/m Correct answer.
  3. 96 kNm/m
  4. 12 kNm/m

Explanation

Treating a 1 m wide strip as a simply supported beam, the moment is wL²/8 = 12 × 16 / 8 = 24 kNm/m. Using a strip width other than 1 m or a wrong coefficient gives the other values.

Question 20Civil Engineering

Which statement about the effective height of a masonry wall is correct?

  1. It is independent of the presence of openings
  2. It is always equal to the clear height between floors
  3. It is reduced by increasing the wall thickness
  4. It depends on the support conditions and stiffening provided by cross walls Correct answer.

Explanation

Effective height reflects how the wall is restrained at its edges, so stiffening from cross walls, floors and returns can reduce it below the clear height. Slenderness and capacity follow from this effective value.

Question 21Civil Engineering

A timber joist is to span 3.5 m and support a uniformly distributed load. Which serviceability check is most likely to govern the design?

  1. Shear stress at midspan
  2. Tension perpendicular to grain at midspan
  3. Deflection under the characteristic load combination Correct answer.
  4. Bearing stress at the supports

Explanation

Timber is relatively flexible, so deflection limits under service loads often govern member sizing for domestic floor joists. Shear and bearing are checked but rarely control such spans.

Question 22Civil Engineering

In limit state design, what is the role of the partial factor applied to permanent actions in the ultimate limit state combination?

  1. To account for creep and shrinkage of concrete
  2. To reduce the characteristic load for serviceability checks
  3. To account for the variability and uncertainty of the action effect Correct answer.
  4. To convert characteristic strength into design strength

Explanation

Partial factors on actions cover the uncertainty and variability of loads and the unfavourable nature of their effects at the ultimate limit state. Factors on material strength are applied separately to resistances.

Question 23Civil Engineering

A short braced reinforced concrete column carries a factored axial load of 3000 kN. The section is 400 mm square with concrete design strength 20 N/mm² and steel design strength 435 N/mm². If 1% reinforcement is provided, what is the approximate design axial resistance?

  1. 6800 kN
  2. 3200 kN
  3. 2400 kN
  4. 4940 kN Correct answer.

Explanation

The resistance is approximately 0.567 fck Ac plus 0.87 fyk As for the concrete and steel contributions, giving a value in the region of 4900 kN. Using the full cylinder strength or omitting one contribution shifts the result substantially.

Question 24Civil Engineering

A propped cantilever of span L carries a uniformly distributed load w. Using elastic analysis, what is the bending moment at the prop?

  1. Zero
  2. wL²/12 (hogging)
  3. wL²/8 (hogging) Correct answer.
  4. wL²/24 (sagging)

Explanation

For a propped cantilever under uniform load, the fixed-end moment at the prop is wL²/8 hogging, while the maximum sagging moment in the span is 9wL²/128. The prop moment is therefore not zero and not the fixed-end value of a fully fixed beam.

Question 25Civil Engineering

In the design of a reinforced concrete beam for torsion, which combination of actions typically requires explicit torsional reinforcement?

  1. Axial compression combined with small eccentricity
  2. Pure torsion below the threshold value with no coexisting shear
  3. Bending alone with no shear
  4. Torsion combined with shear and bending where the torsional stress exceeds the limiting value Correct answer.

Explanation

Codes allow torsion to be ignored below a threshold, but where the torsional shear stress exceeds that limit, closed links and longitudinal steel must be provided to resist torsion in combination with coexisting shear and bending.

Question 26Civil Engineering

In reinforced concrete design, what does the term 'development length' represent for a deformed bar?

  1. The minimum embedment needed to transfer the bar's yield force to the surrounding concrete by bond Correct answer.
  2. The distance over which shear reinforcement must be continued past a support
  3. The lap length required when bars of different diameters are spliced
  4. The distance from the support face to the point where the bar may be curtailed

Explanation

Development length is the anchorage length required so that bond stresses along the bar can develop its design force without the bar pulling out or splitting the concrete. It depends on bar diameter, concrete strength, cover, and confinement. Curtailment, lap splicing, and shear reinforcement extension are separate detailing rules.

Question 27Civil Engineering

Which statement best describes the purpose of a slump test on fresh concrete?

  1. It determines the air content entrapped during mixing
  2. It gives an indication of the workability or consistency of the fresh mix Correct answer.
  3. It measures the compressive strength gain of the mix at early ages
  4. It establishes the required cement content for a target strength class

Explanation

The slump test is a simple site check of the consistency and workability of fresh concrete, indicating how easily it can be placed and compacted. It does not measure strength, air content, or cement content directly. Those properties require separate tests or mix design calculations.

Question 28Civil Engineering

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

  1. 60 kNm
  2. 45 kNm Correct answer.
  3. 30 kNm
  4. 90 kNm

Explanation

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

Question 29Civil Engineering

In structural steelwork, what does the designation S275 refer to?

  1. A steel with a Charpy impact energy of 275 J at room temperature
  2. A steel with a specified minimum yield strength of 275 N/mm² Correct answer.
  3. A steel with a specified minimum tensile strength of 275 N/mm²
  4. A steel with a maximum carbon equivalent of 275 parts per million

Explanation

In the European designation system, the number following S denotes the specified minimum yield strength in N/mm² for the smallest thickness range. S275 therefore has a minimum yield strength of 275 N/mm². Tensile strength, impact energy, and carbon equivalent are given by other symbols in the full designation.

Question 30Civil Engineering

Which foundation type is most appropriate where a structure must be founded on very deep soft clay overlying rock at depth?

  1. A pad footing bearing on the soft clay
  2. A strip footing at shallow depth
  3. A raft foundation bearing directly on the soft clay
  4. Piled foundations transferring load to the rock Correct answer.

Explanation

When suitable bearing strata lie far below a soft compressible layer, piles can be taken down to the rock to carry load through skin friction and end bearing. Shallow strip, pad, or raft foundations on the soft clay would suffer excessive settlement or bearing failure.

Question 31Civil Engineering

What is the main purpose of curing concrete after placement?

  1. To reduce the cement content required in the mix
  2. To maintain adequate moisture and temperature so hydration can continue Correct answer.
  3. To increase the density of the concrete by vibration
  4. To accelerate the removal of formwork

Explanation

Curing keeps the concrete moist and at a suitable temperature so that cement hydration continues and the design strength and durability develop. Without curing, surface drying causes reduced strength and increased cracking and permeability. Curing does not change mix proportions or replace compaction.

Question 32Civil Engineering

In reinforced concrete beams, why are shear links spaced more closely near the supports than at midspan?

  1. Concrete cover requirements are stricter near the supports
  2. Links are required only where the beam is continuous over a support
  3. Shear force is highest near the supports, so more shear reinforcement is needed there Correct answer.
  4. Bending moment is highest at midspan, so links are moved away from it

Explanation

The shear force in a simply supported beam is greatest at the supports and decreases toward midspan. Link spacing follows the shear demand, so links are closer together where the design shear is higher. Moment distribution and cover do not govern link spacing in this way.

Question 33Civil Engineering

Which quantity is used to express the relative density of a granular soil in the field?

  1. Standard penetration test blow count Correct answer.
  2. Coefficient of consolidation
  3. Plasticity index
  4. Liquid limit

Explanation

For granular soils, the standard penetration test blow count (or cone penetration resistance) is commonly correlated with relative density. Plasticity index and liquid limit apply to cohesive soils and describe consistency, not relative density. The coefficient of consolidation describes rate of settlement in clays.

Question 34Civil Engineering

In limit state design of a reinforced concrete beam, what does the balanced section condition describe?

  1. A section in which no compression reinforcement is required for any moment
  2. A section where the steel strain at failure is exactly zero
  3. A section where the neutral axis lies at the tension face
  4. A section where the concrete and steel reach their design limits simultaneously Correct answer.

Explanation

In a balanced section, the tension steel yields at the same time as the concrete reaches its ultimate compressive strain. This gives a balanced reinforcement ratio that separates under-reinforced from over-reinforced behaviour. Sections with steel ratios below this value are ductile and preferred in design.

Question 35Civil Engineering

Which statement correctly explains why a steel column base plate is usually larger than the column cross-section?

  1. It allows the column to be spliced to the column above
  2. It prevents the column from rotating about its major axis
  3. It increases the buckling resistance of the column along its length
  4. It reduces the bearing pressure on the concrete foundation to an acceptable value Correct answer.

Explanation

The base plate spreads the column axial load over a larger area so that the bearing pressure on the concrete foundation remains within the allowable design value. The plate does not control column buckling along its length or provide major-axis rotational restraint. Column splices are separate connections higher up the member.

Question 36Civil Engineering

A concrete mix has a target mean strength of 40 N/mm² and a standard deviation of 5 N/mm². Using the characteristic strength definition, what characteristic strength results?

  1. 45 N/mm²
  2. 25 N/mm²
  3. 30 N/mm² Correct answer.
  4. 35 N/mm²

Explanation

The characteristic strength is defined as the target mean strength minus 1.64 times the standard deviation for a 5% failure probability. Here 40 − 1.64 × 5 ≈ 40 − 8.2 ≈ 31.8 N/mm², and 30 N/mm² is the closest sensible value consistent with the standard margin. The margin of about 1.64 standard deviations is the key concept.

Question 37Civil Engineering

In the design of a steel beam-to-column connection, what distinguishes a 'simple' connection from a 'moment' connection?

  1. A simple connection transfers shear only and is assumed to provide no significant moment restraint Correct answer.
  2. A simple connection transfers moment only and provides no shear resistance
  3. A simple connection is always welded while a moment connection is always bolted
  4. A simple connection is used only for columns in braced frames

Explanation

A simple connection is designed to transmit shear and is assumed to offer negligible rotational restraint, so the beam is treated as simply supported. A moment connection is designed to transmit bending moment as well as shear, providing frame continuity. The distinction is about the actions transferred, not the fastening method.

Question 38Civil Engineering

A rectangular pad footing 2 m by 2 m carries a column load of 800 kN. What is the average bearing pressure on the soil, ignoring footing self-weight?

  1. 400 kN/m²
  2. 100 kN/m²
  3. 200 kN/m² Correct answer.
  4. 800 kN/m²

Explanation

Average bearing pressure equals the load divided by the footing area. The area is 2 × 2 = 4 m², so the pressure is 800 / 4 = 200 kN/m². Ignoring self-weight keeps the calculation to the applied column load only.

Question 39Civil Engineering

Which statement about the effective length of a steel column in a braced frame is correct?

  1. It is always equal to the actual column length regardless of end restraint
  2. It is reduced only by the presence of a base plate
  3. It equals half the column length for all braced frames
  4. It depends on the rotational and translational restraint at its ends Correct answer.

Explanation

The effective length accounts for end restraint conditions, including how much rotation and sway are prevented at each end. It is derived from the actual length multiplied by an effective length factor. Braced frames prevent sway but still allow differing rotational restraint, so the factor is not fixed at one or one-half.

Question 40Civil Engineering

In masonry construction, what is the function of a wall tie?

  1. It provides a damp-proof course at the base of the wall
  2. It resists vertical compressive stress in the wall
  3. It connects the two leaves of a cavity wall and transfers lateral load between them Correct answer.
  4. It anchors the roof to the wall to resist uplift

Explanation

Wall ties link the inner and outer leaves of a cavity wall so that they act together under lateral loading and to accommodate differential movement. They are not the primary compression path, nor are they roof anchors or damp-proofing. Their spacing and type are governed by the wall construction and exposure.

Question 41Civil Engineering

A simply supported timber floor joist spans 4 m and carries a total load of 2 kN/m. What is the maximum bending moment?

  1. 16 kNm
  2. 2 kNm
  3. 8 kNm
  4. 4 kNm Correct answer.

Explanation

For a simply supported span with a uniform load, the maximum moment is wL²/8. Substituting w = 2 kN/m and L = 4 m gives 2 × 16 / 8 = 4 kNm at midspan.

Question 42Civil Engineering

What is the principal reason for specifying a minimum percentage of tension reinforcement in a reinforced concrete beam?

  1. To avoid the need for shear links
  2. To ensure the section behaves in a ductile manner rather than failing suddenly Correct answer.
  3. To reduce the self-weight of the beam
  4. To control the long-term deflection to zero

Explanation

A minimum tension steel ratio ensures that the section is under-reinforced and will show ductile yielding before brittle concrete crushing. This gives warning of failure and improves robustness. Minimum reinforcement does not eliminate shear links, reduce self-weight, or remove deflection.

Question 43Civil Engineering

In a soil, the effective stress is calculated as total stress minus pore water pressure. What happens to effective stress in a saturated sand when the water table rises to the ground surface?

  1. Effective stress at a given depth decreases because pore pressure increases Correct answer.
  2. Effective stress becomes zero at all depths below the water table
  3. Effective stress at a given depth increases because total stress increases
  4. Effective stress remains unchanged because both total stress and pore pressure increase equally

Explanation

Raising the water table increases pore water pressure at a given depth while total stress stays the same. Since effective stress equals total stress minus pore pressure, the effective stress decreases. This is why uplift and reduced bearing capacity can occur with a high water table.

Question 44Civil Engineering

Which statement about the design of a reinforced concrete cantilever retaining wall is correct?

  1. The stem is designed mainly for bending caused by lateral earth pressure, with the heel and toe as cantilevers off the base slab Correct answer.
  2. The base slab is designed solely for the self-weight of the wall
  3. The stem requires no reinforcement because earth pressure acts on the base only
  4. The wall is designed only for vertical load from the retained soil

Explanation

In a cantilever retaining wall, the vertical stem acts as a cantilever fixed to the base and is designed for bending from lateral earth pressure. The heel and toe slabs similarly cantilever from the wall and are designed for the resulting soil and water pressures. Stability against sliding and overturning is checked separately.

Question 45Civil Engineering

In a prestressed concrete beam, what is the effect of increasing the eccentricity of the tendon at midspan, assuming the prestress force is unchanged?

  1. It increases the negative (hogging) moment induced by prestress at midspan, offsetting sagging moment Correct answer.
  2. It has no effect on the stresses at midspan because the force is unchanged
  3. It reduces the prestress force transferred to the concrete
  4. It increases the self-weight of the beam

Explanation

Prestress induces a moment equal to the force times its eccentricity from the centroid. Increasing eccentricity at midspan increases this hogging moment, which counteracts the sagging moment from applied loads and improves the section's load capacity. The prestress force itself is unchanged by eccentricity.

Question 46Civil Engineering

A steel beam has a plastic section modulus of 500 cm³ and a design yield strength of 275 N/mm². What is the plastic moment capacity?

  1. 13.75 kNm
  2. 1375 kNm
  3. 1.375 kNm
  4. 137.5 kNm Correct answer.

Explanation

Plastic moment capacity equals the plastic section modulus times the yield strength. Converting 500 cm³ to 500,000 mm³ and multiplying by 275 N/mm² gives 137.5 × 10⁶ Nmm, or 137.5 kNm. Careful unit conversion is essential in this calculation.

Question 47Civil Engineering

In a reinforced concrete flat slab, why is punching shear reinforcement sometimes required around a column?

  1. The slab needs additional reinforcement to resist global bending at midspan
  2. High concentrated shear stresses near the column can exceed the concrete punching resistance Correct answer.
  3. Punching reinforcement is required to control thermal movement in the slab
  4. It is needed to anchor the column longitudinal bars into the slab

Explanation

The column reaction produces high shear stress around the column perimeter, which can cause a punching failure cone through the slab. Where the concrete alone cannot resist this, shear reinforcement such as links or studs is added. Global bending and thermal movement are handled by other reinforcement and joint details.

Question 48Civil Engineering

A clay layer 4 m thick has a coefficient of consolidation of 2 m²/year and drains at both the top and bottom. Using the standard time factor for 90% consolidation, approximately how long is needed to reach 90% consolidation?

  1. About 1.6 years Correct answer.
  2. About 6.4 years
  3. About 0.8 years
  4. About 3.2 years

Explanation

For 90% consolidation the time factor is about 0.848. With double drainage the drainage path is half the layer thickness, so H = 2 m. Then t = Tv H² / cv = 0.848 × 4 / 2 ≈ 1.7 years, closest to 1.6 years. Using the full thickness instead of the drainage path would overestimate the time by a factor of four.

Question 49Civil Engineering

In the design of a steel plate girder, why are transverse web stiffeners provided at intervals along the span?

  1. To increase the plastic moment capacity of the flanges
  2. To prevent local buckling of the web under shear and concentrated loads Correct answer.
  3. To transfer the flange forces into the end bearings
  4. To reduce the self-weight of the girder

Explanation

Thin webs can buckle under shear and under concentrated loads applied through the flanges. Transverse stiffeners divide the web into panels and raise its buckling resistance. They do not increase flange moment capacity or reduce self-weight, and bearing stiffeners at supports serve a distinct local function.

Question 50Civil Engineering

A simply supported reinforced concrete beam has an effective depth of 500 mm, a lever arm of 0.9d, and a design moment of 200 kNm. Taking the design yield strength of steel as 435 N/mm², what area of tension steel is required?

  1. About 4080 mm²
  2. About 2040 mm²
  3. About 510 mm²
  4. About 1020 mm² Correct answer.

Explanation

Required steel area is M / (0.87 fy z), with z = 0.9 × 500 = 450 mm. Substituting gives 200 × 10⁶ / (0.87 × 435 × 450) ≈ 1020 mm². Checking the lever arm and unit consistency is essential in this calculation.