Question 1

Combined footing fundamentals — which statements are correct? Consider the following statements about combined footings for two columns: (a) The footing is proportioned so that the centroid of the supporting area coincides with the centroid of the t…

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Introduction / Context: Combined footings support two columns with a single slab when isolated footings would overlap or property lines prevent symmetric layouts. Proportioning rules ensure that the soil pressure is uniform (or linearly distributed without tension), which minimizes eccentricity and prevents edge uplift. Given Data / Assumptions: Two axially loaded columns on a common footing. Soil behaves elastically within allowable bearing pressure. Self-weight of footing either neglected in first sizing or added uniformly. Concept / Approach: The resultant of the column loads must pass through the centroid of the footing area to avoid net moment that would cause nonuniform contact pressures. Plan shapes are typically rectangular or trapezoidal. Rectangular shapes are efficient when loads are equal or when the inner column is heavier so that the load resultant lies near the geometric center. Trapezoidal shapes are usually adopted when column loads are unequal or edge constraints shift the resultant; they are not “under any loading” but selected to align centroid locations and geometric limits. Step-by-Step Solution: Evaluate (a): centroid of area = centroid of loads → correct principle for uniform pressure.Evaluate (b): plan shape options → rectangular or trapezoidal → correct.Evaluate (c): when loads are equal or inner column heavier → rectangular is convenient → correct.Evaluate (d): “under any loading” is too broad; shape choice depends on load ratio and geometry → incorrect. Verification / Alternative check: Worked examples show moving from rectangular to trapezoidal when column load ratio significantly deviates or when the property line limits projection on one side, to keep the resultant through the centroid of area. Why Other Options Are Wrong: (b) alone or (a)&(c) alone omit valid information; (d) is false because trapezoidal is not universal; (d) also invalidates “All of…” in option (d). Common Pitfalls: Forgetting that the location of the resultant governs plan shape more than habit. Ignoring column dimensions and projection limits while placing the footing centroid. Final Answer: Only (a), (b), and (c) are correct.

Question 2

Door and window openings — what are the vertical sides called? In wall construction, the two vertical sides of a door or window opening that receive the frame are known as:

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Introduction / Context: Clear terminology around openings aids detailing, finishing, and quantity estimation. Each component around a door/window has a specific name used in drawings and specifications. Given Data / Assumptions: Masonry or framed wall with a formed opening. Door/window frame fitted to the opening. Standard building terminology. Concept / Approach: The vertical members of an opening that receive and abut the frame are called jambs. The term reveal refers to the exposed return surface of the wall at right angles to the frame (often the plastered return), whereas “verticals” is not a standard technical term in this context. Correct naming avoids confusion in specifications such as “plaster to reveals” vs. “fix frame to jambs”. Step-by-Step Solution: Identify element: the two vertical sides of the wall opening → jambs.Differentiate: reveals = exposed return surfaces; jambs = structural sides receiving the frame.Conclude: correct term is “Jambs”. Verification / Alternative check: Architectural glossaries and standard details consistently label the two vertical sides of an opening as jambs, with head and sill as the horizontal top and bottom. Why Other Options Are Wrong: “Verticals” is generic and non-technical. “Reveals” are the perpendicular returns, not the sides themselves. “None of these” is wrong because “Jambs” is correct. Common Pitfalls: Confusing frame members (also called jambs) with the wall jambs; context clarifies usage. Final Answer: Jambs.

Question 3

Brick bonds — identify the bond with alternate courses and a three-quarter bat starter Which bond lays headers and stretchers in alternate courses, with every stretcher course starting with a three-quarter brick bat at the quoin to maintain bond?

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Introduction / Context: Brick bonds control strength, appearance, and joint stagger. Different bonds arrange headers and stretchers in specific sequences and use cut bricks (bats/closers) at ends to maintain proper overlap. Given Data / Assumptions: Standard modular bricks and typical course heights. Correct use of three-quarter bats at quoins for certain bonds. Focus on plan/elevation pattern rather than structural testing. Concept / Approach: Dutch bond uses alternate courses of headers and stretchers, with each stretcher course beginning with a three-quarter bat to keep vertical joints staggered. English cross bond maintains perpends in a different periodic manner; Monk bond uses two stretchers to one header in each course; Rat-trap bond turns bricks on edge to create a cavity, improving thermal performance but producing a different pattern altogether. Step-by-Step Solution: Identify bond requirement: alternate courses of headers and stretchers.Check starter piece: three-quarter bat in each stretcher course.This matches Dutch bond → select “Dutch bond”. Verification / Alternative check: Bond diagrams in masonry texts illustrate Dutch bond with the distinctive three-quarter bat at the start of stretcher courses to align perpends correctly. Why Other Options Are Wrong: English cross bond and Monk bond have different header-to-stretcher sequencing. Rat-trap bond is a cavity bond with different geometry and purpose. Common Pitfalls: Confusing the use of bats (length cuts) with closers (width cuts) at quoins. Final Answer: Dutch bond.

Question 4

Timber pile groups — typical centre-to-centre spacing for design and driving What is a commonly adopted centre-to-centre spacing for timber piles in a group to ensure drivability, load sharing, and reasonable cap size (assume typical pile diameters)?

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Introduction / Context: Pile spacing affects group action, drivability, and pile cap economy. Too-close spacing risks pile-to-pile interaction during driving and increases negative group effects; too-wide spacing enlarges the cap and may reduce group efficiency minimally but at higher cost. Given Data / Assumptions: Timber piles of typical diameters used in building/bridge works. Conventional group caps with reinforcement and practical driving tolerances. Soils where group action is relevant. Concept / Approach: Rules of thumb suggest spacing of about 2.5 to 3.0 times pile diameter (centre-to-centre) for friction piles; for small-diameter timber piles this often works out close to ~0.9 m. This spacing balances pile group effects and cap size while giving adequate room for driving and alignment tolerances. Step-by-Step Solution: Assume typical timber pile diameter 30–35 cm.Compute 2.5D to 3.0D → approximately 0.75–1.05 m.Nearest listed standard spacing ≈ 0.90 m → select 90 cm. Verification / Alternative check: Design handbooks and standard drawings frequently show timber pile spacing near 0.9 m for small-to-medium diameters, with adjustments for soil type and cap geometry. Why Other Options Are Wrong: 50–80 cm may be too tight for driving and risk excessive group interaction for typical diameters. Common Pitfalls: Ignoring larger diameters or battered piles, which may call for wider spacing. Forgetting construction tolerances that require clear spacing between piles. Final Answer: 90 cm.

Question 5

Retaining and breast walls — purpose of providing weep holes Why are weep holes provided through retaining/breast walls (with proper filters) toward the exposed face?

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Introduction / Context: Backfill behind retaining walls can become saturated due to rainfall and seepage. Water adds hydrostatic pressure and reduces the effective stress and shear strength of the soil, threatening wall stability. Weep holes provide a pressure-relief path for water to escape safely through the wall. Given Data / Assumptions: Gravity or RC cantilever retaining/breast walls. Free-draining layer or geotextile/filter behind the wall. Proper spacing and invert level near the base. Concept / Approach: Weep holes work with drainage blankets or pipes to dissipate pore pressures. Their placement is typically near the toe region where water accumulates. Filters prevent soil piping and loss of fines. With water pressures relieved, sliding, overturning, and bearing checks are less critical and more economical sections are achievable. Step-by-Step Solution: Identify problem: water build-up in backfill → extra hydrostatic pressure.Provide solution: weep holes + drainage layer → pressure relief and safe discharge.Result: improved stability and durability; less seepage-induced damage. Verification / Alternative check: Standard details place weep holes with graded filters or geotextiles and often include a perforated collector pipe to direct flows to outlets. Why Other Options Are Wrong: (b) No need for “ventilation” through structural walls; airflow is not the purpose. (c) Aesthetic perforations are not sound engineering. (d) Weep holes do not reduce earth mass weight in any meaningful way. (e) They do not increase compaction; they drain water. Common Pitfalls: Omitting filters, causing soil piping and staining. Placing weep holes too high, leaving pore water trapped at the base. Final Answer: To drain off water from the backfill and relieve hydrostatic pressure.

Question 6

Hospital/X-ray facility finishes — plaster used for radiation shielding X-ray rooms require wall finishes that attenuate ionizing radiation. Which plaster is commonly specified to improve shielding performance (often used with lead lining or high-de…

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Introduction / Context: Diagnostic imaging suites must control X-ray leakage through room envelopes. Besides structural provisions like lead sheets and heavy concrete/blocks, high-density plasters can be specified to add attenuation where appropriate. The correct material choice improves staff and public safety and aids compliance with radiation regulations. Given Data / Assumptions: Internal wall finish inside X-ray rooms. Supplemental measure; not a substitute for lead where shielding calculations require it. Focus on plaster types used specifically for radiation attenuation. Concept / Approach: Barium plaster incorporates barium sulfate or similar heavy fillers to increase density and thus attenuation of X-ray photons. It is often specified with thickness verified by shielding calculations. Plaster of Paris is for general finishing/moulding. Martin’s and Keen’s cements are specialized hard plasters but not intended for radiation shielding. Step-by-Step Solution: Identify need: higher density wall finish for attenuation.Select specialized mix: barium-loaded plaster → improved shielding.Confirm alternatives: PoP and hard plasters are not radiation-specific. Verification / Alternative check: Radiation protection guidelines list barium plaster as an acceptable supplementary shielding material where design calculations show it is adequate, usually alongside lead sheets or dense concrete as primary barriers. Why Other Options Are Wrong: Plaster of Paris is lightweight and not shielding-focused. Martin’s and Keen’s cements are for hard, smooth finishes but not for radiation attenuation. Common Pitfalls: Assuming barium plaster alone suffices without shielding calculations; always verify required lead equivalence. Final Answer: Barium plaster.

Question 7

Waterproofing admixtures — making ordinary concrete more water resistant Which option correctly identifies materials that are added to fresh concrete as integral waterproofing compounds to reduce permeability (as opposed to paints or surface coating…

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Introduction / Context: Reducing water ingress through concrete can be achieved by proper mix design, curing, detailing, and, when specified, by integral waterproofing admixtures. This question distinguishes integral admixtures from surface-applied products that do not change the permeability of the concrete matrix itself. Given Data / Assumptions: Ordinary structural or masonry concrete exposed to moisture. Goal is to lower permeability by admixture within the mix. Trade names represent integral compounds (Pudlo, Impermo, Cico) vs. paints (Snowcem). Concept / Approach: Integral waterproofing compounds (pore-blocking or hydrophobic) are dosed into the concrete to reduce capillary absorption and permeability. Surface paints like Snowcem are protective coatings applied after curing; they do not transform the internal pore structure of hardened concrete. Bitumen primers are unrelated to concrete mix permeability and are used as surface coatings or bonding agents in waterproofing systems. Simply increasing cement content is not a reliable waterproofing strategy and may raise shrinkage risk. Step-by-Step Solution: Define objective: reduce permeability from within the concrete matrix.Identify suitable materials: integral compounds Pudlo/Impermo/Cico.Eliminate surface-only treatments and incorrect practices. Verification / Alternative check: Manufacturers’ data sheets show reductions in water absorption and permeability with integral admixtures when used alongside low w/c ratio and proper curing. Why Other Options Are Wrong: Snowcem is a paint; it does not alter internal permeability. Bitumen primer is a coating/primer, not an admixture. Higher cement alone does not guarantee waterproof concrete. “All of these” conflates admixtures with coatings and is incorrect. Common Pitfalls: Relying on admixtures while neglecting cracks, joints, and curing—major leakage pathways. Final Answer: Pudlo/Impermo/Cico-type integral waterproofing compound.

Question 8

Soil mechanics — properties of gravels as an aggregate fraction Which consolidated statement about gravels is most appropriate in introductory soil/aggregate classification?

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Introduction / Context: In soil classification and aggregate grading, “gravel” denotes the coarser, cohesionless fraction above sands. Understanding its basic mechanical and volume-change behavior guides foundation and pavement design decisions, particularly regarding compaction, drainage, and susceptibility to heave/shrinkage. Given Data / Assumptions: General engineering classification (e.g., gravels vs. sands vs. fines). Typical, not code-specific, size descriptions. Clean gravels without excessive fines. Concept / Approach: Gravels are cohesionless; their strength derives from interparticle friction and dilation under load. Particle sizes begin above the sand fraction (about 2 mm) and extend upward through coarse gravels and cobbles depending on the system used (some standards define 2–60 mm or 4.75–75 mm bands). Unlike clays and silts, clean gravels show negligible swell on wetting and minimal shrinkage on drying because they lack the active clay minerals responsible for volumetric changes. Step-by-Step Solution: Evaluate (a): cohesionless → correct, frictional behavior dominates.Evaluate (b): size threshold above sands (≈ 2 mm) → correct as a general descriptor.Evaluate (c) and (d): negligible swell/shrink compared with fine-grained soils → correct.Therefore, all listed statements together describe gravels well. Verification / Alternative check: Unified/Indian/road specifications use slightly different size cutoffs, but all place gravel above sand sizes and treat gravels as coarse, cohesionless aggregates with minimal volume-change tendencies. Why Other Options Are Wrong: Picking any single statement misses the full description; the comprehensive choice “All of the above” is most accurate. Common Pitfalls: Assuming behavior of gravelly soils with high fines content; fines can introduce cohesion and volume change. Final Answer: All of the above.

Question 9

Brick closers — identify the piece cut through the centre of width In brick masonry terminology, what do you call the piece obtained by cutting a brick along the middle of its width so that its length remains equal to a full brick (used to maintain …

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Introduction / Context: Bonding in brick masonry requires occasional use of specially cut bricks known as closers. These ensure that vertical joints are staggered properly, especially at corners (quoins), to achieve structural integrity and aesthetic regularity. This question checks recognition of the correct closer produced by cutting a brick along the centre of its width while retaining the full length. Given Data / Assumptions: A standard rectangular brick is considered. The cut is made along the centre of the width (i.e., longitudinally). The resulting piece keeps the full brick length but has half the width. Concept / Approach: When a brick is cut longitudinally into two equal halves, the product is called a queen closer. Its dimensions become approximately L × (W/2) × H, where L is unchanged. Queen closers are typically placed next to quoin headers in English bond to avoid continuous vertical joints. This distinguishes them from king closers (which taper) and other special cuts used for specific bonding patterns. Step-by-Step Solution: Identify the cut direction: along width ⇒ reduces width to half, length unchanged.Match with masonry terms: the piece with full length and half width is a queen closer.Confirm typical use: placed at quoins to maintain proper lap in bonds like English bond. Verification / Alternative check: Standard bonding diagrams in textbooks show queen closers immediately adjacent to quoin headers, providing the necessary break in vertical joints through successive courses. Why Other Options Are Wrong: half brick: refers to a brick cut to half its length, not width. king closer: a triangular/tapered closer cut from corner to mid-point, not a simple half-width piece. bevelled closer: end is bevelled; not the described longitudinal halving. none of these: incorrect because queen closer fits exactly. Common Pitfalls: Confusing “half brick” (half length) with “queen closer” (half width); mixing up king and queen closer shapes. Final Answer: queen closer

Question 10

Timber roof trusses — standard carpentry joints in a king-post truss Choose the correct combined statement about the typical joints used in a king-post roof truss between its principal members.

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Introduction / Context: Traditional timber trusses rely on well-crafted carpentry joints to transfer axial forces and prevent rotation or slip. The king-post truss is the simplest roof truss with a central vertical king post tying the tie beam to the principal rafters. Knowing the conventional joints helps ensure load paths and durability. Given Data / Assumptions: Members: tie beam, principal rafters, king post, and struts. Common historical joinery terminology: mortice-and-tenon, bridle joints, etc. Loads transmitted primarily as axial forces. Concept / Approach: A bridle joint (open mortice) at the rafter–tie interface provides a large bearing area and resists rotation. Mortice-and-tenon joints are classic for connecting timber members such as rafters/struts to the king post; pegs or wedges may secure them to resist withdrawal. These joints align fibres and accommodate compression along the grain while controlling shear at the interfaces. Step-by-Step Solution: Map each connection to the most appropriate joint per carpentry practice.Rafter–tie: bridle joint is standard for seat and bearing.Rafter–king post: mortice-and-tenon provides positive location and shear transfer.Strut–king post: mortice-and-tenon again suits axial compression transfer. Verification / Alternative check: Historic manuals and conservation guides depict these exact joints in king-post trusses, often with draw-bored pegs. Why Other Options Are Wrong: Any single statement alone is incomplete; all three are correct together. None of these: incorrect since all listed joints are standard. Common Pitfalls: Substituting nails/bolts without considering long-term slip and creep; poor fibre orientation reducing bearing capacity. Final Answer: All the above

Question 11

Plastering operations — term for working a flat to receive the finishing coat In plasterwork, what is the operation called in which the undercoat is worked and made true, level, and keyed with a float so that it is ready to receive the finishing coa…

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Introduction / Context: Plastering is applied in stages: preparation of background, dubbing out (filling hollows), undercoat(s), floating, and finish coat. Proper terminology matters because each stage has specific workmanship requirements that affect durability and appearance of the final surface. Given Data / Assumptions: The question refers to preparing the undercoat to receive the finishing coat. Tool used: float (wood or plastic) to level and key the surface. Conventional multi-coat plaster system. Concept / Approach: Floating is the process of working the undercoat with a float to produce an even, plane, and slightly keyed surface appropriate for the finish. Dubbing out fills localized depressions before floating. Knetting is not a standard plastering term; blistering is a defect where bubbles appear due to poor adhesion or rapid drying, not a planned operation. Step-by-Step Solution: Identify goal: create a true, even base for the finishing coat.Select operation: floating with a float to level and key the undercoat.Exclude other terms: dubbing out (filling), blistering (defect), knetting (non-standard). Verification / Alternative check: Trade specifications describe “float coat” and “floating” as essential steps prior to the finish, especially in cement-lime-sand systems. Why Other Options Are Wrong: dubbing out: preliminary filling, not final preparation for the finish. knetting: not recognised as a plastering operation. blistering: a failure mode, not a process. Common Pitfalls: Skipping floating leads to uneven finish, poor key for the top coat, and increased cracking due to variable thickness. Final Answer: floating

Question 12

Allowable bearing capacity of granite (order of magnitude) What is the typical safe bearing capacity range (in kg/cm²) adopted in practice for foundations resting on hard granite rock, assuming sound, unweathered material and normal safety factors?

Accepted Answer

Introduction / Context: Foundation design on rock depends on rock quality designation, discontinuities, weathering, and surface preparation. For strong, massive rocks such as granite, the controlling factors are often discontinuities and bearing area rather than compressive strength of intact rock, which is very high. Engineers therefore use empirical safe bearing values for preliminary design before site-specific tests. Given Data / Assumptions: Sound, unweathered granite. Joints and seams properly evaluated; foundation area prepared. Safe bearing capacity refers to working (allowable) values with usual safety margins. Concept / Approach: Granite has very high compressive strength (intact strengths can exceed thousands of kg/cm²), but allowable bearing pressure for foundations is limited by mass behaviour, joints, and settlement criteria. Typical tabulated values for hard rocks are in the tens of kg/cm², with granite commonly cited around the higher end of such ranges. Among the options, 40–45 kg/cm² reflects this order of magnitude for safe bearing in practice. Step-by-Step Solution: Recognise hard rock category → high allowable pressures compared to soils.Compare options by magnitude: tens vs single digits.Select the highest listed range consistent with strong granite: 40–45 kg/cm². Verification / Alternative check: Preliminary values in many handbooks list hard rock at several MPa (equivalently tens of kg/cm²). Final design should be based on plate load tests or rational analysis when critical. Why Other Options Are Wrong: 5–10, 15–20, 30–35 kg/cm²: conservative for hard, sound granite; more typical of weaker rock or heavily jointed conditions. None of these: incorrect because 40–45 kg/cm² is reasonable. Common Pitfalls: Ignoring joint orientation and persistence; extrapolating allowable pressure from intact strength; neglecting drainage and weathering at the rock surface. Final Answer: 40 to 45 kg/cm²

Question 13

Cavity wall design — maximum recommended width of the air cavity In a standard cavity wall (two leaves tied across an air gap), the width of the hollow space between the leaves should not exceed which value for typical building practice?

Accepted Answer

Introduction / Context: Cavity walls improve resistance to rain penetration and enhance thermal performance. The cavity width, however, must be controlled so that wall ties function properly, the cavity can be kept clear of mortar droppings, and thermal and moisture objectives are met without excessive overall thickness. Given Data / Assumptions: Residential or commercial buildings in typical exposure conditions. Standard cavity ties used at normal spacings. No special insulation boards counted inside the cavity in this question. Concept / Approach: Common practice adopts cavity widths in the range of 5–10 cm. Narrow cavities risk bridging by mortar droppings; overly wide cavities complicate tying and stability. Hence, many specifications cap the plain air cavity at or below 10 cm unless special ties and design details are used. This balances moisture control with structural integrity and economy. Step-by-Step Solution: Consider tie effectiveness and constructability limits.Adopt the widely accepted upper bound for conventional practice: 10 cm.Therefore, do not exceed 10 cm in typical designs. Verification / Alternative check: Manufacturer guidance for cavity wall ties usually specifies maximum tie spans that align with a 50–100 mm cavity range for standard applications. Why Other Options Are Wrong: 5 cm, 7.5 cm: permissible but not the maximum; question asks for the upper limit. 15 cm: generally beyond standard practice without special design. None of these: incorrect because 10 cm is the commonly used limit. Common Pitfalls: Allowing mortar droppings to bridge the cavity; ignoring weep holes and cavity trays above openings; not adjusting tie type/spacing for nonstandard widths. Final Answer: 10 cm

Question 14

Stair design guideline — maximum recommended pitch (slope) of a stair What is the usual maximum pitch (angle to the horizontal) recommended for stairs in buildings to ensure comfortable and safe movement?

Accepted Answer

Introduction / Context: Stair pitch is a key ergonomic factor affecting safety and comfort. Excessive steepness leads to fatigue and accident risk; too shallow a slope is space-inefficient. Building practice therefore limits the pitch within a preferred range and sets a clear maximum for general occupancy stairs. Given Data / Assumptions: Ordinary buildings, not ladders or industrial stairs. Riser and going satisfy comfort rules (e.g., 2r + g ≈ 600–650 mm). Uniform treads and risers across the flight. Concept / Approach: Many codes and standards recommend a preferred pitch between roughly 25° and 40°, with 40° commonly cited as an upper limit for regular stairs. Within this range, normal riser/going proportions yield a comfortable stride and acceptable footprint, balancing safety and layout constraints. Step-by-Step Solution: Relate pitch to riser/going proportions.Adopt upper limit used in practice for normal buildings: 40°.Confirm that steeper angles (50–60°) correspond to ladders or ship stairs, not regular building stairs. Verification / Alternative check: Example: riser = 170 mm, going = 260 mm gives pitch ≈ arctan(170/260) ≈ 33°, within the preferred range and well below 40°. Why Other Options Are Wrong: 25°, 30°: allowable but not the maximum; these are typical comfortable pitches. 50°, 60°: too steep for building stairs; unsafe for normal use. Common Pitfalls: Inconsistent risers/goings causing trip hazards; ignoring headroom and landing requirements. Final Answer: 40°

Question 15

Pointing terminology — select the single correct statement Which ONE of the following statements correctly matches a mortar-joint finish with its standard name in brick masonry?

Accepted Answer

Introduction / Context: Pointing provides a durable, weather-resisting finish to exposed joints in brick masonry. Different profiles change both appearance and rain-shedding performance. Knowing the standard names avoids confusion in specifications and site execution. Given Data / Assumptions: Common pointing types considered: flush, recessed, keyed (concave), struck/weathered, beaded, ruled, and tuck pointing. We must pick exactly one correct statement. Concept / Approach: Keyed (concave) pointing is formed by running a rounded steel tool to produce a concave surface, which is good at shedding rain and resisting erosion. Tuck pointing produces a narrow raised fillet (often white) over a flush joint and is not the same as a joint broadly projecting beyond the face. Ruled pointing is a flush or slightly recessed joint impressed with a narrow groove (rule line), not an inclined surface. A uniformly recessed joint is called recessed pointing, whereas beaded pointing forms a raised bead, not a uniform recess. Step-by-Step Solution: Check each description against standard pointing definitions.Option (a) matches the textbook definition of keyed pointing.Options (b), (c), and (d) mislabel other pointing types. Verification / Alternative check: Illustrations in building construction texts depict keyed pointing as concave; tuck as a raised false joint; ruled as a grooved line; recessed as a set-back joint. Why Other Options Are Wrong: (b) Confuses tuck (raised fillet) with a general projecting joint; projecting joints are called raised or beaded. (c) Inward-upward sloped joints are struck/weathered, not ruled. (d) A uniform recess is “recessed pointing,” not “beaded.” Common Pitfalls: Mixing up terminology, especially tuck vs beaded; assuming any groove is “ruled” regardless of the base profile. Final Answer: A joint finished with a concave profile using a rounded steel tool is called a keyed joint

Question 16

Isolated column footings — choose the correct combined statement Which of the following statements about isolated footings for columns are correct in standard building practice?

Accepted Answer

Introduction / Context: Isolated footings are the most common shallow foundation for individual columns in buildings. Their geometry and reinforcement are tailored to spread load, control shear and bending, and achieve economical construction while meeting serviceability requirements. Given Data / Assumptions: Columns carry axial load (and possibly some moment). Footing placed on compacted soil with adequate bearing capacity. Standard detailing used for reinforcement and offsets. Concept / Approach: An isolated footing transfers column loads to soil; steps or projections help achieve the required bearing area and reduce concrete volume compared to a uniform thick slab. Heavily loaded bases require two-way reinforcement to resist bending in both orthogonal directions. A practical concrete projection (offset) of roughly 150 mm on each side beyond the footing edge is a common detailing guideline to ensure cover, workable edge distances, and formwork stability (exact values vary by code and design). Step-by-Step Solution: Evaluate each statement against standard foundation practice.(a) True — it is the very purpose of an isolated footing.(b) True — stepped/projection bases are widely used.(c) True — two-way bending requires reinforcement in both directions for heavy loads.(d) True — a minimum practical offset around 15 cm is customary (subject to design). Verification / Alternative check: Typical detailing handbooks show two-way reinforced pads with plan projections and, where required, shear checks and punching reinforcement near columns. Why Other Options Are Wrong: Choosing any single statement omits other equally correct aspects. Common Pitfalls: Ignoring punching shear at column faces; neglecting soil variability; omitting adequate cover at footing edges. Final Answer: All the above

Question 17

Brick nogging partitions — method of construction Brick nogging type partition walls are constructed by which of the following methods?

Accepted Answer

Introduction / Context: Brick nogging is a traditional method for creating lightweight internal partitions and for infilling timber frames. It combines the speed and economy of brickwork with a structural timber skeleton that carries the main loads, leaving the nogging primarily as infill and for stiffness and fire separation. Given Data / Assumptions: Partition (non-loadbearing) application. Conventional timber studs and rails forming bays. Thin brick units laid within the bays. Concept / Approach: In brick nogging, brickwork is built inside a timber frame between studs and rails. The timber frame resists vertical loads; the brick infill adds mass, fire resistance, and some lateral stiffness. This is distinct from a standalone brick wall (stretchers or headers) and from mere strapping of a wall with iron bands. Proper ties and allowances for movement between brick and timber are necessary to avoid cracking. Step-by-Step Solution: Identify primary structural system: timber frame carrying loads.Recognise nogging: brick infill within the frame bays.Select the method describing brickwork within a wooden framework. Verification / Alternative check: Historic half-timbered construction and modern adaptations illustrate brick nogging between timber members, often with lath and plaster finishes over. Why Other Options Are Wrong: (a) and (b) describe freestanding masonry bonds, not nogging. (c) Iron straps alone do not define nogging construction. (e) Incorrect because (d) is correct. Common Pitfalls: Rigidly connecting nogging to timber without movement joints; inadequate tying leading to gaps; moisture incompatibility between materials. Final Answer: Building brickwork infill within a timber (wooden) framework

Question 18

Roof forms for snowy mountainous regions — recommended choice For buildings located in high mountainous regions with heavy snowfall, which roof form is generally recommended to shed snow effectively and reduce accumulation?

Accepted Answer

Introduction / Context: Snow-prone mountainous regions demand roof geometries that quickly shed snow to limit structural loads and prevent ice dams. Roof selection also influences detailing of eaves, gutters, and ventilation to minimise freeze–thaw damage and leakage risk. Given Data / Assumptions: Climate: frequent heavy snowfall. Goal: reduce snow accumulation and sliding hazards while simplifying structure. Conventional residential/commercial buildings. Concept / Approach: A gable roof with adequate pitch (steeper than typical lowland roofs) allows snow to slide off both slopes symmetrically, reducing unbalanced loads and simplifying framing. A simple ridge-and-two-slopes strategy eases construction and detailing. Shed roofs can also work if pitched steeply, but may cause asymmetrical loading and drifting on the high wall. Gambrel and mansard forms have change-of-slope breaks that trap snow near the lower steep-to-shallow transition and complicate waterproofing, making them less suitable in heavy snow zones. Step-by-Step Solution: Prioritise rapid snow shedding and simple detailing.Select a symmetric, steeply pitched form: gable roof.Avoid multi-slope forms (gambrel/mansard) with ledges that trap snow. Verification / Alternative check: Snow load codes and alpine building guides favour simple steep gable roofs with snow guards and robust eave details to handle sliding snow safely. Why Other Options Are Wrong: Shed: feasible but less ideal due to asymmetry and drift at high wall. Gambrel/Mansard: multiple slope breaks trap snow; complex flashing details. None of these: incorrect because gable is appropriate and widely recommended. Common Pitfalls: Insufficient pitch; weak eave and gutter design collapsing under sliding snow; lack of snow guards above entrances. Final Answer: gable roof

Question 19

Masonry Materials – Minimum compressive strength of mortar for load-bearing brickwork In the context of load-bearing brick masonry, what is the minimum compressive strength that the mortar should achieve (express your choice in N/cm² as given in the…

Accepted Answer

Introduction / Context: Mortar strength is a key parameter for load-bearing brick masonry because it governs the bond between bricks and the compressive performance of the wall. Codes and handbooks group mortars into classes with specified 28-day strengths. For basic load-bearing work in conventional buildings, a minimum specified strength threshold is adopted to ensure adequate safety and serviceability. Given Data / Assumptions: Brickwork is load-bearing, not merely infill. Mortar strength is the 28-day cube/compression value. Options are provided in N/cm²; 100 N/cm² equals 1 MPa. Concept / Approach: Low-strength mortars may be acceptable for non-load-bearing partitions, but load-bearing masonry requires a minimum class to resist axial compression and to develop reliable bond. A commonly cited benchmark for minimum mortar class in load-bearing brickwork is about 1 MPa (100 N/cm²). This level balances constructability, economy, and performance for typical small to medium structures. Step-by-Step Solution: Interpret units: 100 N/cm² = 1 MPa; 50 N/cm² = 0.5 MPa; 150 N/cm² = 1.5 MPa; 200 N/cm² = 2 MPa.Identify the minimum level that is generally specified for load-bearing: ≈ 1 MPa.Choose the option that matches 1 MPa: 100 N/cm². Verification / Alternative check: Many schedules of mortar classes show grades around 1 MPa or higher for load-bearing walls, while richer mixes (higher MPa) are used when higher masonry strengths are required or in severe exposure conditions. Why Other Options Are Wrong: 50 N/cm²: too weak for load-bearing work. 150 or 200 N/cm²: stronger than the minimum; acceptable, but the question asks for the minimum. 250 N/cm²: likewise higher than necessary for the specified minimum. Common Pitfalls: Confusing brick compressive strength with mortar strength; both influence masonry strength, but mortar minimums ensure adequate bond and bed performance. Also, ensure proper curing and joint thickness control to achieve the specified strength. Final Answer: 100 N/cm²

Question 20

Soil Classification – Key characteristics of silt soils (size range and plasticity) Which of the following statements about silt soils is/are correct in standard geotechnical usage?

Accepted Answer

Introduction / Context: Correctly identifying silt is fundamental in soil classification and design. Silt lies between clay and sand in particle size and typically shows low plasticity. Misclassification can lead to poor predictions of compressibility, permeability, and strength, directly affecting foundation design and earthworks. Given Data / Assumptions: Particle size limits follow common systems used in practice (e.g., about 0.002–0.06 mm for silt). “Inorganic silt” is considered when discussing plasticity characteristics. Quartz is a common mineral in silt-size fractions. Concept / Approach: Silt grains are larger than clay minerals yet finer than sand. Because inorganic silts have limited surface activity compared to clays, they display low plasticity indices. Equi-dimensional, quartz-rich silts are typically the least plastic, with behaviour dominated by grain-to-grain contact rather than electrochemical effects common in clays. Step-by-Step Solution: Check size range: adopt ~0.002–0.06 mm as the practical band for silt.Assess plasticity: inorganic silts commonly show little or no plasticity (non-plastic to low PI).Relate mineralogy/shape to plasticity: quartz-rich, equi-dimensional grains make silts the least plastic within fines. Verification / Alternative check: Atterberg limit tests on silts often return non-plastic or low plasticity values, confirming their distinct behaviour from clayey fines. Why Other Options Are Wrong: “Only (a) and (b)” ignores the well-known connection between grain shape/mineralogy and plasticity captured in (c). Common Pitfalls: Assuming all fines are “clay”; silt can appear similar in the field yet behaves very differently under loading and wetting. Always verify with particle size analysis and Atterberg limits. Final Answer: All of the above

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