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Past Questions — 2010
With a percentage increase of carbon in steel, it decreases its
A)
strength
B)
hardness
C)
ductility
D)
brittleness
Steel is an alloy of iron and carbon. The properties of steel are heavily influenced by the carbon content. As the percentage of carbon increases:
1. Strength increases: Carbon atoms fit into the interstitial sites of the iron lattice, hindering the movement of dislocations.
2. Hardness increases: The increased resistance to plastic deformation makes the material harder.
3. Brittleness increases: As the material becomes harder and stronger, it becomes less capable of plastic deformation before failure, making it more brittle.
4. Ductility decreases: Ductility is the ability of a material to undergo significant plastic deformation before rupture (e.g., being drawn into a wire). Because carbon restricts the sliding of atomic planes (dislocations), the material's ability to deform plastically is reduced. Therefore, an increase in carbon leads to a decrease in ductility.
Commonly used raw materials in manufacturing cement is
A)
slate
B)
sand stone
C)
lime stone
D)
basalt
Portland cement is manufactured by heating a mixture of calcareous (calcium-bearing) and argillaceous (silica and alumina-bearing) materials.
1. **Lime stone (Calcium Carbonate - CaCO3)**: This is the primary raw material used to provide Calcium Oxide (CaO), which is the most significant constituent of cement (approximately 60-67%).
2. **Argillaceous materials**: Clay, shale, or blast furnace slag are used to provide Silica (SiO2), Alumina (Al2O3), and Iron Oxide (Fe2O3).
Analyzing the options:
- **a. Slate**: While slate contains some silica and alumina, it is not a primary or commonly used raw material for cement production.
- **b. Sand stone**: Sandstone is primarily silica; while silica is needed, it is typically sourced from clay or shale in a balanced ratio with lime.
- **c. Lime stone**: This is the fundamental source of calcium, making it the most essential and commonly used raw material.
- **d. Basalt**: Basalt is an igneous rock and is not used as a standard raw material in the chemical process of cement manufacturing.
Brass is an alloy of
A)
steel
B)
copper
C)
aluminium
D)
nickel
Brass is a non-ferrous alloy primarily composed of copper (Cu) and zinc (Zn). Depending on the desired properties (such as corrosion resistance or strength), the proportions of these two metals are varied.
Analysis of options:
- a. Steel: Steel is an alloy of iron and carbon, not a base component of brass.
- b. Copper: Correct. Copper is the primary base metal in brass.
- c. Aluminium: Aluminium is a base metal for alloys like Duralumin, but not brass.
- d. Nickel: Nickel is used in alloys like Monel or Nichrome, or as an additive in some specialized brasses (nickel silver), but it is not the primary constituent of standard brass.
The minimum thickness of the cover at the end of reinforcing bar should not be less than twice the diameter of the bar subject to a minimum of
A)
10 mm
B)
15 mm
C)
20 mm
D)
25 mm
According to the standard codes of practice for Reinforced Cement Concrete (RCC), specifically referring to the guidelines for the placement of reinforcement and concrete cover, the cover at the end of a reinforcing bar (the termination point) must be sufficient to prevent the splitting of the concrete and to protect the steel from corrosion. The rule specifies that the minimum thickness of the cover at the end of a reinforcing bar should not be less than twice the diameter of the bar (2φ), subject to a minimum absolute value of 25 mm. This ensures that even for small diameter bars, there is a minimum threshold of concrete protection to maintain structural integrity and durability.
Statistically determinate structures are those in which
A)
stresses are developed due to temperature variation
B)
stresses are developed due to lack of fit
C)
conditions of equilibrium are not sufficient to fully analyse the structures
D)
none of the above
Determinate structures need only equilibrium; stresses due to temperature/lack of fit and insufficiency of equilibrium are properties of indeterminate, so none of given statements defines determinate.
Distribution of shear intensity over a rectangular section, follows
A)
a straight line
B)
a circular curve
C)
an elliptical curve
D)
a parabolic curve
The shear stress (intensity) at any point in a cross-section of a beam is given by the formula: τ = (V * Q) / (I * b), where V is the shear force, Q is the first moment of area above the point of interest, I is the moment of inertia, and b is the width of the section. For a rectangular section of width 'b' and depth 'd', the first moment of area Q varies quadratically with the distance 'y' from the neutral axis. Specifically, Q = ∫(y * dA), which results in a quadratic expression in terms of y. Consequently, the shear stress distribution τ varies as a function of y², which mathematically represents a parabolic curve. The shear stress is zero at the top and bottom fibers and reaches its maximum value (1.5 times the average shear stress) at the neutral axis. Therefore, the distribution is parabolic.
Rollers are used for
A)
excavation
B)
compaction
C)
removing excavated earth
D)
none of the above
Rollers are heavy construction machines specifically designed to densify soil, gravel, concrete, or asphalt. This process is known as 'compaction,' which involves removing air voids from the material to increase its load-bearing capacity and stability.
Analysis of options:
- (a) Excavation: This is the process of removing earth, typically performed by excavators, backhoes, or shovels, not rollers.
- (b) Compaction: This is the primary function of rollers (e.g., smooth wheel rollers, sheep-foot rollers, pneumatic tyred rollers).
- (c) Removing excavated earth: This is the function of hauling equipment such as dumpers, tippers, or scrapers.
- (d) None of the above: Incorrect, as option (b) is the standard engineering definition of a roller's purpose.
The deflection due to couple M at free end of a cantilever of length L is
A)
ML / EI
B)
ML2 / 2EI
C)
2ML / EI
D)
M2L / 2EI
Cantilever with end moment M: slope=ML/EI, integration gives deflection ML^2/(2EI).
The law which states that within elastic limits strain produced is proportional to the stress producing it, is known as
A)
Poisson’s law
B)
Bernoulli’s law
C)
stress law
D)
Hooke’s law
The question describes the fundamental principle of elasticity.
1. **Hooke's Law**: Formulated by Robert Hooke, this law states that for an elastic material, the strain produced is directly proportional to the stress applied, provided the limit of proportionality (which is within the elastic limit) is not exceeded. Mathematically, it is expressed as Stress (σ) = E × Strain (ε), where E is the Modulus of Elasticity.
2. **Analysis of other options**:
- **Poisson's law (Poisson's Ratio)**: Relates the lateral strain to the longitudinal strain in a material under axial load; it does not define the proportionality between stress and strain.
- **Bernoulli's law**: A principle of fluid dynamics relating pressure, velocity, and elevation in a moving fluid; it is unrelated to the strength of materials.
- **Stress law**: This is not a standard, named scientific law in materials science; 'stress' is a physical quantity, not a law of proportionality.
Therefore, the correct answer is Hooke's law.
The stress in the wall of a cylinder in a direction normal to its longitudinal axis, due to a force acting along the circumference, is
A)
yield stress
B)
longitudinal stress
C)
circumferential stress
D)
hoop stress
In the study of thin-walled pressure vessels (cylinders), there are two primary types of normal stresses acting on the walls due to internal pressure: 1. Longitudinal Stress: This acts parallel to the longitudinal axis of the cylinder. 2. Circumferential Stress: This acts in a direction normal (perpendicular) to the longitudinal axis, effectively trying to 'burst' the cylinder along its length. This circumferential stress is specifically termed as 'Hoop Stress'. The formula for hoop stress is σ = Pd/2t (where P is internal pressure, d is diameter, and t is wall thickness). While 'circumferential stress' (option c) is a descriptive term for the direction, 'hoop stress' (option d) is the standard technical term used in Strength of Materials to describe this specific stress state. In most competitive exams, 'hoop stress' is the preferred technical answer for stress acting along the circumference.
The section of a reinforced beam where the most distant concrete fibre in compression and tension in steel attains a permissible stresses simultaneously, is called
A)
balanced section
B)
economic section
C)
critical section
D)
all the above
In the design of reinforced concrete beams (Working Stress Method), a 'balanced section' is defined as a section in which the concrete in the compression zone and the steel in the tension zone reach their respective maximum permissible stresses simultaneously under the same loading condition.
1. **Balanced Section (Option a):** By definition, if the actual depth of the neutral axis coincides with the critical depth of the neutral axis, both materials reach their limit simultaneously. This is the theoretical point of balance.
2. **Under-reinforced Section:** The steel reaches its permissible stress first, while the concrete is still below its limit. This is generally preferred for safety (ductile failure).
3. **Over-reinforced Section:** The concrete reaches its permissible stress first, while the steel is below its limit. This is avoided as it leads to sudden, brittle failure.
4. **Economic Section (Option b):** This refers to a section designed to utilize materials most efficiently, but it is not the technical term for the simultaneous attainment of stresses.
5. **Critical Section (Option c):** In RCC, 'critical section' usually refers to the location of maximum shear or bending moment, not the stress state of the materials within the cross-section.
The most popular type of organization used in civil engineering construction is
A)
line of organization
B)
line and staff organization
C)
functional organization
D)
effective organization
In civil engineering construction, projects are complex and require both a clear chain of command (for execution) and specialized technical expertise (for planning, quality control, and design).
1. **Line Organization (Option a):** This is the simplest form where authority flows vertically from top to bottom. While clear, it is insufficient for large construction projects because the manager cannot be an expert in every technical field (e.g., structural, electrical, plumbing).
2. **Line and Staff Organization (Option b):** This is the most popular in construction. It combines the direct authority of the 'Line' (Project Manager -> Site Engineer -> Foreman) with the specialized knowledge of 'Staff' (Technical consultants, HR, Accountants, Quality Assurance). The staff provides advice and support, but the line managers retain the authority to make decisions and give orders. This balance is ideal for the multidisciplinary nature of civil engineering.
3. **Functional Organization (Option c):** Here, employees report to multiple specialists based on the function. This often leads to confusion and conflict of command (violating the unity of command principle), making it less popular for on-site construction management.
4. **Effective Organization (Option d):** This is a general descriptive term, not a formal structural type of organizational theory.
Portal frame, a statically indeterminate structure can be analysed by
A)
the strain energy method
B)
moment distribution method
C)
slope deflection method
D)
all the above methods
A portal frame is a statically indeterminate structure, meaning the equations of static equilibrium (sum of forces and moments) are insufficient to determine all internal forces and reactions. To solve such structures, compatibility equations or energy methods must be used.
1. **The Strain Energy Method (Option a):** This is a fundamental approach (including Castigliano's theorems) used to solve indeterminate structures by minimizing the total strain energy or using the principle of least work. It is highly effective for portal frames.
2. **Moment Distribution Method (Option b):** Developed by Hardy Cross, this is an iterative displacement method specifically designed to solve indeterminate beams and frames by distributing unbalanced moments at joints until equilibrium is reached.
3. **Slope Deflection Method (Option c):** This is a stiffness-based displacement method that expresses joint moments in terms of joint rotations and displacements. It provides a set of simultaneous equations that can be solved to find the internal forces of a portal frame.
Since all three methods are valid and widely used techniques for the analysis of statically indeterminate portal frames, the correct answer is 'all the above methods'.
In a grillage footing, the maximum shear force occurs at
A)
centre of grillage beam
B)
edge of grillage beam
C)
centre of base plate
D)
none of the above
A grillage footing consists of a network of beams (usually I-sections) laid in two layers at right angles to each other to distribute a heavy concentrated load over a larger area of soil. In such a system, the beams act as members supporting a distributed reaction from the soil. For a beam subjected to a concentrated load at the center and a uniformly distributed reaction from the soil (upward), the shear force is maximum at the supports or the ends of the beam. In the context of a grillage beam, the shear force increases from the center (where it is zero for a symmetrical load) toward the edges/ends of the beam. Therefore, the maximum shear force occurs at the edge of the grillage beam. Option (a) is incorrect because the shear force is minimum (zero) at the center of a symmetrically loaded beam. Option (c) is incorrect because the base plate transmits the load to the beams; while the load is concentrated there, the internal shear force within the grillage beams themselves reaches its peak at the extremities.
When a load is transferred through one surface to another surface in contact, the stress is known as
A)
tensile stress
B)
compressive stress
C)
working stress
D)
shearing stress
When a load is transferred from one surface to another surface in contact, the force acts parallel to the plane of contact. This type of stress, where the internal forces act tangential to the surface of the material, tending to cause one layer of the material to slide over another, is defined as shearing stress.
Analysis of other options:
- Tensile stress: Occurs when two forces act in opposite directions away from each other, tending to elongate the body.
- Compressive stress: Occurs when two forces act toward each other, tending to shorten or compress the body.
- Working stress: This is not a type of stress based on direction of force, but rather the maximum allowable stress a material is subjected to during its service life to ensure safety.
In a singly reinforced beam, if the permissible stress in concrete reaches earlier than the permissible stress in steel, beam section is called
A)
under reinforced section
B)
over reinforced section
C)
critical section
D)
economic section
In the design of reinforced concrete beams (Working Stress Method), the behavior of the section depends on the relative amount of steel provided compared to the balanced amount.
1. **Over-reinforced Section**: A section is called over-reinforced if the area of steel provided is greater than the balanced area of steel. In this case, the steel is 'too strong' for the concrete. Consequently, as the load increases, the concrete reaches its maximum permissible compressive stress while the steel is still under-stressed. This leads to a sudden, brittle failure of the concrete, which is undesirable in engineering.
2. **Under-reinforced Section**: A section is under-reinforced if the area of steel is less than the balanced area. Here, the steel reaches its permissible stress first, leading to a ductile failure characterized by large deflections and cracks, providing a warning before collapse.
3. **Critical (Balanced) Section**: A section is balanced if both the concrete and steel reach their permissible stresses simultaneously.
4. **Economic Section**: This refers to the most cost-effective design, typically leaning towards an under-reinforced section to ensure safety through ductility.
Since the question specifies that the permissible stress in concrete is reached earlier than that of steel, the section is an over-reinforced section.
The first test of construction is
A)
initiation of proposal
B)
survey of the site
C)
preparation of estimate
D)
preparation of tender
In the lifecycle of a construction project, the process follows a logical sequence of planning and execution.
1. Initiation of Proposal: This is the very first step. Before any technical work begins, there must be a need identified, a conceptual idea, or a formal proposal to undertake the project. This stage involves defining the project's purpose, feasibility, and basic requirements.
2. Survey of the Site: Once the proposal is initiated and approved in principle, a site survey is conducted to understand the topography, soil conditions, and boundaries to inform the design.
3. Preparation of Estimate: Based on the survey and preliminary designs, a detailed cost estimate is prepared to secure funding and budget approval.
4. Preparation of Tender: After the estimates and final designs are ready, tender documents are prepared to invite contractors to bid for the execution of the work.
Therefore, the initiation of the proposal is the foundational step that triggers all subsequent activities.
The figure shown below indicates
A)
a merge
B)
an event
C)
an activity
D)
a burst
In event network diagram merging of multiple activities into one event is a merge; bursting is divergence.
The performance of specific task in CPM is known as
A)
dummy
B)
event
C)
activity
D)
contract
In the Critical Path Method (CPM), the fundamental components are activities and events.
1. **Activity (Option c):** An activity is defined as a specific task or a piece of work that consumes time and resources (e.g., 'excavation' or 'pouring concrete'). It is represented by an arrow in an activity-on-node or activity-on-arrow diagram. Therefore, the performance of a specific task is termed an 'activity'.
2. **Event (Option b):** An event is a specific point in time that marks the start or completion of one or more activities. It does not consume time or resources; it is merely a milestone.
3. **Dummy (Option a):** A dummy activity is an imaginary activity used in CPM networks to show a logical dependency between two activities. It consumes zero time and zero resources.
4. **Contract (Option d):** A contract is a legal agreement between two parties and is not a technical component used to define tasks within a CPM network diagram.
The age of trees can be predicted by
A)
the thickness of bark
B)
counting number of rings
C)
length of modularly rays
D)
measuring the diameter of pitch
The age of a tree can be determined through a process called dendrochronology. In most woody plants, the vascular cambium produces a new layer of xylem (wood) every growing season. This results in the formation of 'annual rings' (growth rings), consisting of earlywood (lighter, faster growth in spring) and latewood (darker, slower growth in autumn). By counting these concentric rings from the pith (center) to the bark, one can accurately predict the age of the tree in years.
Why other options are incorrect:
- a. Thickness of bark: Bark thickness varies based on species, environmental exposure, and protection needs; it does not increase linearly with age.
- c. Length of modularly rays: Medullary rays are radial files of cells that transport nutrients; their length is a structural characteristic of the species, not a chronological marker.
- d. Measuring the diameter of pitch: The 'pitch' (or pith) is the central core of the stem. While the overall diameter of the trunk increases with age, it is not a reliable predictor because growth rates vary wildly based on soil quality, water availability, and sunlight.
Plywood is normally available in thickness of
A)
1 mm
B)
2 mm
C)
2 to 3 mm
D)
3 to 4 mm
Plywood is a manufactured board made from thin layers of wood veneers glued together. In the context of standard civil engineering materials and timber technology, the individual veneers (the thin sheets of wood) used to construct the plywood are typically produced in thicknesses ranging from 2 mm to 3 mm. While the final plywood board can be very thick (depending on how many layers are glued together), the question refers to the standard thickness of the constituent veneers available for production. Options a and b are generally too thin for structural stability during the peeling process, and option d is typically the upper limit or exceeds the standard thin-veneer range used for common commercial plywood.
The average shear stress of rolled steel beam section is
A)
8290 N/cm2
B)
9270 N/cm2
C)
14715 N/cm2
D)
10055 N/cm2
In the design of steel structures according to Indian Standard codes (such as IS 800), the permissible shear stress for rolled steel sections is typically taken as a fraction of the yield stress of the material. For structural steel with a yield stress (fy) of 250 MPa (which is 250 N/mm²), the permissible shear stress is often calculated as 0.4 times the yield stress (τ = 0.4 * fy).
Calculation:
1. Permissible shear stress (τ) = 0.4 × 250 N/mm² = 100 N/mm².
2. To convert N/mm² to N/cm²:
1 mm² = 0.01 cm²
Therefore, 1 N/mm² = 100 N/cm².
3. 100 N/mm² × 100 = 10,000 N/cm².
Among the given options, 10055 N/cm² is the closest value to the standard theoretical permissible shear stress for common structural steel grades used in rolled sections. In many competitive exams based on older versions of the code or specific material grades (like Fe 250), this value is the standard accepted answer for the average shear stress capacity of a rolled steel beam section.
Web crippling generally occurs at a point where
A)
bending moment is maximum
B)
shearing force is minimum
C)
concentrated load acts
D)
deflection is maximum
Web crippling is a localized failure mode in steel I-beams or channels. It occurs due to high compressive stresses in the web caused by concentrated loads or reaction forces. When a concentrated load is applied to the top flange, it transmits that force through the web. If the web is too thin or lacks sufficient support (like stiffeners), the web can buckle locally or 'crush' under the intense localized pressure, leading to web crippling.
Analysis of other options:
- (a) Maximum bending moment typically leads to yielding of the flanges or lateral-torsional buckling, not localized web crippling.
- (b) Shearing force minimum: Web crippling is related to high localized pressure, not the minimum shear force.
- (d) Maximum deflection: Deflection is a global serviceability limit state and does not cause the localized instability known as web crippling.
A member which does not regain its original shape after removal of load producing deformation is said to be
A)
plastic
B)
elastic
C)
rigid
D)
none of the above
In the study of Strength of Materials, materials are classified based on their deformation behavior under load:
1. **Elasticity (Option b):** A material is said to be elastic if it regains its original shape and size immediately after the applied load is removed. This is known as elastic deformation.
2. **Plasticity (Option a):** A material is said to be plastic if it undergoes permanent deformation and does not return to its original shape after the load is removed. This occurs when the stress applied exceeds the elastic limit (or yield point) of the material. This is known as plastic deformation.
3. **Rigidity (Option c):** A rigid body is a theoretical idealization where no deformation occurs regardless of the load applied. In reality, no material is perfectly rigid.
Since the question describes a member that 'does not regain its original shape,' it is describing plastic behavior.
PVC stands for
A)
plastic very compact
B)
polythene vinyl carbon
C)
polythene vanadium carbide
D)
polythene vinyl chloride
PVC is a widely used synthetic plastic polymer. The acronym stands for Polyvinyl Chloride. In the context of the provided options, 'polythene vinyl chloride' is the intended answer, although technically 'Polyvinyl Chloride' is the precise chemical name. It is produced by the polymerization of vinyl chloride monomers (CH2=CHCl).
Analysis of options:
- Option (a) 'plastic very compact' is a descriptive phrase, not a chemical name.
- Option (b) 'polythene vinyl carbon' is chemically incorrect as carbon is an element, not a functional group in this naming convention.
- Option (c) 'polythene vanadium carbide' is incorrect as vanadium is a transition metal and not part of the PVC structure.
- Option (d) 'polythene vinyl chloride' correctly identifies the 'Vinyl Chloride' component of the polymer.