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Past Questions
Hoe is used for
A)
rolling
B)
compaction
C)
excavation
D)
none of the above
A 'Hoe' (specifically a backhoe or power hoe in construction equipment) is a piece of heavy machinery designed specifically for digging. It consists of a digging bucket attached to a hydraulic arm, which is used to scoop material from the ground.
Analysis of options:
- a. Rolling: This is performed by rollers (e.g., smooth wheel rollers, sheep-foot rollers) to flatten surfaces.
- b. Compaction: This is the process of increasing soil density, achieved using compactors, rollers, or rammers.
- c. Excavation: This is the process of removing earth/soil from a site. A hoe is a primary tool used for this purpose.
- d. None of the above: Incorrect, as option c is the primary function of the equipment.
Trailers are used
A)
as hauling equipments
B)
to trail the excavation
C)
as compaction equipments
D)
all the above
In construction and civil engineering, trailers are non-powered vehicles designed to be towed by a tractor or a truck. Their primary function is the transportation (hauling) of heavy materials, equipment, or excavated soil from one location to another.
Analysis of options:
- Option (a) is correct because 'hauling' refers to the act of transporting loads, which is the sole purpose of a trailer.
- Option (b) 'to trail the excavation' is not a standard technical term or function in construction equipment operations.
- Option (c) 'as compaction equipments' is incorrect; compaction is performed by rollers, rammers, or vibratory plates, not by trailers.
- Option (d) is incorrect because options (b) and (c) are invalid.
The kiln which may work regularly throughout the year is
A)
Bull’s kiln
B)
Hoffman’s kiln
C)
Clamp
D)
none of the above
The correct answer is Hoffman's kiln because it is designed for continuous operation. Here is the detailed breakdown:
1. **Hoffman's Kiln (Continuous Kiln):** This is a circular or oval kiln consisting of a series of interconnected chambers. The firing process is continuous; while some chambers are being loaded with raw bricks, others are being fired, and others are being cooled. The heat from the firing chambers is used to preheat the bricks in adjacent chambers, making it highly fuel-efficient and allowing it to work regularly throughout the year without needing to be cooled down completely.
2. **Bull's Trench Kiln (Intermittent/Semi-continuous):** While more efficient than a clamp, the Bull's kiln operates in cycles. It involves loading, firing, and cooling phases. Although it can produce large quantities, it is not as 'continuous' in its operational cycle as the Hoffman kiln.
3. **Clamp (Intermittent):** A clamp is a temporary structure where bricks are stacked and fired. Once the firing is complete, the clamp must be dismantled to retrieve the bricks. It is a seasonal, batch-process method and cannot work regularly throughout the year.
Therefore, due to its regenerative heating system and multi-chamber design, the Hoffman's kiln is the only option that allows for uninterrupted, year-round production.
Maximum permissible slenderness ratio of compressive members which carry dead and superimposed load, is
A)
80
B)
180
C)
280
D)
380
According to the Indian Standard code for steel design (IS 800), the slenderness ratio (λ = L_e / r) is limited to prevent excessive buckling and ensure structural stability. For compressive members (columns/struts) that are subjected to dead loads and superimposed loads (permanent loads), the maximum permissible slenderness ratio is specified as 180.
Breakdown of limits for compressive members:
1. Members carrying dead and superimposed loads: Maximum λ = 180.
2. Members carrying only wind or seismic loads (temporary/lateral loads): Maximum λ = 250.
Comparing this to the options provided:
- Option (a) 80: Too restrictive; not the standard limit.
- Option (b) 180: Correct as per IS 800 standards for permanent loads.
- Option (c) 280: Exceeds the limit for standard compressive members.
- Option (d) 380: Far exceeds the permissible limits for structural stability in compression.
The test strength of the sample of concrete is taken as average of the strength of
A)
2 specimens
B)
3 specimens
C)
4 specimens
D)
5 specimens
According to standard codes of practice for concrete testing (such as IS 456:2000 and IS 516 in India, which govern RCC design and testing), the compressive strength of concrete is determined by testing cubes. To ensure statistical reliability and account for variations in casting and curing, a 'sample' is defined as a set of three specimens. The 'test strength' of that specific sample is calculated as the arithmetic average of the compressive strengths of these three specimens. If the difference between any one specimen and the average exceeds a certain percentage (usually 15%), the test results may be considered unreliable. Therefore, the standard procedure is to take the average of 3 specimens.
If p is the internal stress in a thin cylinder of diameter d and thickness t, hoop stress developed is
A)
pd/t
B)
pd/2t
C)
pd/4t
D)
pd/3t
In a thin-walled cylindrical pressure vessel, the internal pressure (p) creates stresses in the walls of the cylinder. There are two primary types of stresses: Hoop (Circumferential) Stress and Longitudinal Stress.
1. **Hoop Stress (σh):** This is the stress acting along the circumference of the cylinder. To derive it, consider a section of the cylinder of length L. The bursting force acting on the projected area is (Pressure × Projected Area) = p × (d × L). This force is resisted by the two walls of the cylinder, each with an area of (t × L).
Therefore, Hoop Stress (σh) = (Bursting Force) / (Resisting Area) = (p * d * L) / (2 * t * L) = pd / 2t.
2. **Longitudinal Stress (σl):** This is the stress acting along the axis of the cylinder. The force acting on the end cap is p × (πd²/4). This is resisted by the annular area of the wall (πdt).
Therefore, Longitudinal Stress (σl) = (p * πd²/4) / (πdt) = pd / 4t.
Since the question specifically asks for the 'hoop stress', the correct formula is pd/2t.
If D is the overall thickness of the slab, the diameter of the reinforcing bars should not exceed
A)
D/4
B)
D/5
C)
D/6
D)
D/8
In the design of reinforced concrete slabs, there are specific limits on the diameter of reinforcing bars to ensure proper concrete flow, avoid congestion, and prevent the slab from becoming too 'ribbed' or prone to cracking. According to standard RCC design guidelines (and specifically referenced in various Indian Standard codes and textbooks for slab design), the maximum diameter of the reinforcing bar should not exceed one-fifth of the overall thickness of the slab (D/5). This ensures that the concrete can be properly compacted around the bars and that the slab maintains its structural integrity as a planar element.
- Option (a) D/4 is too large and may lead to congestion or cracking.
- Option (c) D/6 and (d) D/8 are more conservative limits that might be used in specific high-precision contexts but are not the general standard limit for slab thickness.
Vibrator used in concrete
A)
improves consolidation
B)
makes concrete stronger and durable
C)
removes voids in concrete
D)
all the above
Concrete vibration is a process used to compact freshly placed concrete. Here is the step-by-step reasoning for each option:
1. **Improves Consolidation (Option a):** Consolidation is the process of removing entrapped air from the concrete mix. Vibrators apply high-frequency vibrations that rearrange the concrete particles into a denser state, thereby improving consolidation.
2. **Removes Voids (Option c):** When concrete is poured, air pockets (voids) are naturally trapped. These voids act as weak points. Vibrators force these air bubbles to rise to the surface and escape, effectively removing voids and honeycombing.
3. **Makes Concrete Stronger and Durable (Option b):** Strength and durability are directly related to the density of the concrete. By removing voids and improving consolidation, the concrete becomes denser. A denser concrete matrix has lower permeability (reducing the ingress of harmful chemicals) and higher compressive strength.
Since all three statements are correct and interrelated (vibration leads to void removal, which leads to consolidation, which ultimately results in higher strength and durability), the correct answer is 'all the above'.
The maximum twisting moment a shaft can resist, is a product of the permissible shear stress and
A)
moment of inertia
B)
polar moment of inertia
C)
polar modulus
D)
modulus of rigidity
The torsion equation for a circular shaft is given by: T/J = (τ/r) = (Gθ/L), where T is the twisting moment (torque), J is the polar moment of inertia, τ is the shear stress, r is the radius of the shaft, G is the modulus of rigidity, θ is the angle of twist, and L is the length. To find the maximum twisting moment (T) a shaft can resist based on a permissible shear stress (τ_max), we rearrange the formula: T = τ_max * (J/r_max). The term (J/r_max) is defined as the Polar Modulus (Zp). Therefore, T = τ_max * Zp.
Analysis of options:
- a. Moment of Inertia (I): Used for bending stress, not torsion.
- b. Polar Moment of Inertia (J): T is proportional to J, but the relationship with stress requires dividing by the radius.
- c. Polar Modulus (Zp): Correct, as it is the ratio of the polar moment of inertia to the maximum radius (J/r).
- d. Modulus of Rigidity (G): This relates to the stiffness/deformation (angle of twist), not the maximum stress capacity.
The various activities of project are shown in bar charts by
A)
vertical lines
B)
horizontal lines
C)
crosses
D)
dots
In construction management, a bar chart (commonly known as a Gantt Chart) is a tool used for project scheduling. In this chart, the vertical axis (Y-axis) lists the various activities or tasks of the project, while the horizontal axis (X-axis) represents the time scale (days, weeks, or months). Each activity is represented by a horizontal bar (or line) whose length corresponds to the duration of that activity. The start and end points of the horizontal line indicate the scheduled start and finish dates of the task. Therefore, activities are shown by horizontal lines. Vertical lines are typically used as grid lines to mark specific dates or milestones, and crosses or dots are not standard representations for activity durations in bar charts.
The bending moment is the maximum on a section where shear force is
A)
is equal
B)
is maximum
C)
is minimum
D)
changes sign
In the study of Strength of Materials and Structural Analysis, there is a fundamental mathematical relationship between the Shear Force (V) and the Bending Moment (M). The rate of change of the bending moment with respect to the distance (x) along the beam is equal to the shear force at that section. Mathematically, this is expressed as: dM/dx = V. According to calculus, a function (M) reaches its maximum or minimum value (stationary point) when its first derivative (dM/dx) is equal to zero. Therefore, the bending moment is maximum or minimum where the shear force (V) is zero. For the shear force to be zero, it must either be zero across a segment or, more commonly, cross the zero axis, which means it 'changes sign' (from positive to negative or vice versa). Thus, the maximum bending moment occurs at the section where the shear force changes sign.
On steel structures, dead load is the weight of
A)
steel work
B)
material supported permanently
C)
material fastened to steel work
D)
all the above
In structural engineering, 'Dead Load' refers to the permanent, static loads that act on a structure throughout its entire lifespan. These loads are constant and do not change over time.
1. **Steel work (Option a):** The self-weight of the structural members (beams, columns, trusses) is a primary component of the dead load.
2. **Material supported permanently (Option b):** This includes permanent fixtures such as flooring slabs, roofing sheets, walls, and permanent partitions that are supported by the steel frame.
3. **Material fastened to steel work (Option c):** This includes permanent attachments such as cladding, piping, HVAC ducting, and electrical conduits that are fixed to the structural steel.
Since all three categories represent permanent weights that the structure must support, they all fall under the definition of dead load. Therefore, option 'd' is the correct choice.
The portion A of the reinforced concrete retaining wall shown below is called
A)
stem
B)
heel slab
C)
toe slab
D)
none of the
Without figure, Portion A typical denotes vertical stem of cantilever retaining wall; heel and toe are base slabs.
The most versatile, labour-saving hauling equipment is
A)
truck
B)
dump trucks
C)
dumper
D)
trailer
In construction equipment and earth-moving operations, hauling equipment is evaluated based on versatility (ability to handle different terrains and materials) and labor-saving capacity (efficiency in loading and unloading).
1. **Dump Trucks (Option b):** These are considered the most versatile because they can travel on both paved roads and off-road construction sites. They are highly labor-saving because they feature a hydraulic tipping mechanism that allows the material to be unloaded automatically without manual shoveling or external machinery, significantly reducing man-hours.
2. **Trucks (Option a):** A general truck typically requires manual unloading or a separate crane/loader, making it less labor-saving than a dump truck.
3. **Dumper (Option c):** While similar to dump trucks, 'dumper' often refers to site dumpers which are specialized for rough terrain but lack the road-legality and versatility of a standard dump truck for long-distance hauling.
4. **Trailer (Option d):** Trailers are passive units that require a towing vehicle and usually require significant labor or specialized equipment to unload the cargo, making them the least labor-saving option among the choices.
As the percentage of steel increases
A)
depth of neutral axis increases
B)
depth of neutral axis decreases
C)
lever arm increases
D)
lever arm decreases
Increased steel area needs larger compression area for moment equilibrium, so neutral axis depth increases (lever arm reduces).
A simply supported beam of span L carries a uniformly distributed load of w/unit length. The maximum bending moment is
A)
wL2/4
B)
wL2/8
C)
wL2/12
D)
wL2/16
Step-by-step derivation for a simply supported beam with a uniformly distributed load (UDL):
1. **Reaction Calculation**: For a beam of length L with a UDL of w per unit length, the total load is W = w * L. Due to symmetry, the vertical reactions at the supports (R1 and R2) are equal: R1 = R2 = (wL) / 2.
2. **Bending Moment Equation**: The bending moment M at any distance 'x' from one support is given by the sum of moments of the forces to the left of that section:
M(x) = (R1 * x) - (w * x * x/2)
M(x) = (wL/2)x - (wx²/2)
3. **Finding Maximum Bending Moment**: The maximum bending moment occurs where the shear force is zero. For a symmetric simply supported beam with UDL, this occurs at the center (x = L/2).
4. **Substitution**: Substitute x = L/2 into the moment equation:
M_max = (wL/2)(L/2) - (w(L/2)²/2)
M_max = (wL²/4) - (wL²/8)
M_max = (2wL² - wL²) / 8
M_max = wL²/8
Therefore, option (b) is correct. Options (a), (c), and (d) represent incorrect coefficients resulting from incorrect integration or different loading/support conditions.
When plates of thickness t are exposed to weather, tacking rivets are provided at a pitch in line not exceeding
A)
8 t
B)
16 t
C)
24 t
D)
32 t
In steel structure design, specifically regarding riveted or bolted joints, 'tacking rivets' (or tacking bolts) are used to hold plates in position before the final riveting/bolting process is completed. When plates are exposed to weather, there is a risk of moisture entering the gap between the plates, which can lead to corrosion or 'rusting' of the internal surfaces. To prevent the plates from separating or shifting due to environmental factors and to maintain a tight fit, tacking rivets are provided. According to standard engineering practice and structural codes for steelwork, the pitch of these tacking rivets in a line should not exceed 32 times the thickness of the plate (32t). This ensures sufficient clamping force and stability across the length of the joint during the fabrication and exposure phase. Options a, b, and c provide pitches that are unnecessarily tight and not in accordance with standard structural specifications for this specific purpose.
The neutral axis of T-beam exists
A)
within the flange
B)
at the bottom edge of the slab
C)
below the slab
D)
all the above
In the analysis of a T-beam (a reinforced concrete beam with a T-shaped cross-section), the position of the neutral axis (NA) depends on the magnitude of the applied load, the depth of the flange (slab), and the amount of reinforcement provided. There are three primary cases:
1. **Neutral Axis within the flange (Option a):** This occurs when the compressive force required to balance the tension in the steel is small enough to be provided by the concrete in the flange alone. In this case, the beam behaves like a rectangular beam of width equal to the flange width.
2. **Neutral Axis at the bottom edge of the slab (Option b):** This is the critical transition case where the depth of the neutral axis is exactly equal to the thickness of the flange (slab).
3. **Neutral Axis below the slab (Option c):** This occurs when the compressive force required is greater than what the flange can provide. The neutral axis then shifts down into the web of the beam. In this scenario, the beam is analyzed as a combined flange and web section.
Since the neutral axis can reside in any of these positions depending on the specific design parameters and loading conditions of the beam, all the provided options are possible. Therefore, 'all the above' is the correct choice.
Stress in members of statically determinate simple frames can be determined by
A)
method of joints
B)
method of section
C)
graphical method
D)
all the above
Simple determinate frames can be solved by joints, sections, or graphical methods, all are valid.
Which of the following mortars is most suitable for construction work in waterlogged areas?
A)
cement mortar
B)
lime mortar
C)
gauged mortar
D)
mud mortar
Step-by-step reasoning: 1. Analysis of the environment: Waterlogged areas subject construction materials to constant moisture, seepage, and potential chemical attacks from groundwater. 2. Evaluation of Cement Mortar: Cement mortar (a mixture of Portland cement and sand) is hydraulic, meaning it sets and hardens under water. It provides high compressive strength, low permeability, and superior durability in damp conditions. 3. Evaluation of Lime Mortar: Pure lime mortar is non-hydraulic (sets by absorbing CO2 from the air). In waterlogged areas, it may fail to set properly or may dissolve/leach over time, leading to structural failure. 4. Evaluation of Gauged Mortar: Gauged mortar is a mixture of cement and lime. While better than pure lime, it is generally less water-resistant and has lower strength than pure cement mortar in saturated conditions. 5. Evaluation of Mud Mortar: Mud mortar is completely soluble in water and would wash away or lose all structural integrity in a waterlogged area. Conclusion: Due to its hydraulic properties and strength, cement mortar is the most suitable choice for waterlogged environments.
A solid shaft of diameter d is subjected to torque T. The maximum normal stress induced in the shaft is
A)
16T / pi*d3
B)
32T / pi*d3
C)
zero
D)
none of the above
Torsional shear tau=16T/pi d^3; principal stresses +-tau, so max normal=tau=16T/pi d^3.
The crushing strength of good quality stone should be always greater than
A)
100 N/mm2
B)
80 N/mm2
C)
60 N/mm2
D)
40 N/mm2
In civil engineering and building materials science, the compressive strength (crushing strength) of stone is a primary indicator of its quality and suitability for structural use. For a stone to be classified as 'good quality' or 'strong' for heavy-duty engineering purposes (such as foundations, bridge piers, and load-bearing walls), it is generally required to have a crushing strength exceeding 100 N/mm² (or 100 MPa). Stones with strengths between 60 and 100 N/mm² are often considered of medium strength, while those below 60 N/mm² are considered weak. Therefore, to ensure 'good quality' for general structural standards, the threshold is typically set at 100 N/mm².
Modular co-ordination of construction means
A)
planning
B)
designing
C)
execution
D)
all the above
Modular coordination is a system of standardization in the construction industry. It involves the use of a 'module' (a standard unit of measurement) to ensure that building components, materials, and dimensions are compatible.
1. Planning: Modular coordination starts at the planning stage to determine the overall dimensions of the structure based on standard module sizes to minimize waste.
2. Designing: During the design phase, architects and engineers use these modules to specify the sizes of walls, windows, doors, and other components so they fit together perfectly without the need for on-site cutting or modification.
3. Execution: During execution (construction), modular coordination allows for the use of prefabricated components that can be quickly and accurately assembled on-site, reducing labor time and material wastage.
Since modular coordination is integrated into every phase of the project lifecycle—from the initial concept to the final assembly—it encompasses planning, designing, and execution.
A ferrous metal is
A)
steel
B)
cast iron
C)
wrought iron
D)
all the above
A ferrous metal is defined as a metal that contains iron (Fe) as its primary constituent.
1. Steel: An alloy of iron and carbon (usually with carbon content less than 2%), making it a ferrous metal.
2. Cast Iron: An alloy of iron and carbon (usually with carbon content greater than 2%), making it a ferrous metal.
3. Wrought Iron: A nearly pure form of iron with very low carbon content and small amounts of slag, making it a ferrous metal.
Since all three options (steel, cast iron, and wrought iron) are iron-based materials, they are all classified as ferrous metals.
The distance c.g. of compression and c.g. of tension flanges of a plate girder, is known as
A)
overall depth
B)
clear depth
C)
effective depth
D)
none of these
In the design of plate girders, the following terms are used to define the depth of the section:
1. **Overall Depth (a):** This is the total distance from the extreme top fiber of the compression flange to the extreme bottom fiber of the tension flange.
2. **Clear Depth (b):** This is the distance between the inner faces of the compression and tension flanges (essentially the height of the web plate).
3. **Effective Depth (c):** This is defined as the distance between the center of gravity (c.g.) of the compression flange and the center of gravity (c.g.) of the tension flange. This is the critical dimension used in calculating the moment of resistance of the girder (M = Force × Effective Depth).
Since the question specifically asks for the distance between the c.g. of the compression and tension flanges, the correct term is 'effective depth'.