JKSSB JE Civil Mock Test - 5 - Civil Engineering (CE) MCQ

PERT approach takes account of the uncertainties. In this approach, 3-time values are associated which each activity. So it is probabilistic.

Whereas CPM involves the critical path which is the largest path in the network from starting to ending event and defines the minimum time required to complete the project. So it is deterministic.

Detailed estimate:
A detailed estimate is the most accurate method and consists of working out the quantities of each item of works and working the cost. The dimensions are taken directly from the drawings and quantities of each item are calculated. Finally abstracting and billing is done.
This is prepared in two stages.

1. Details of measurements and calculation of quantities
2. Abstract of Estimated Cost

In the first stage, the quantity, availability, and transportation of materials parameters is being analyzed.
In the second stage, the total abstract of the above analysis is shown.

• Bitumen: Petroleum product obtained by distillation of petroleum crude.
• Cut Back Bitumen: Viscosity reduced by volatile dilutant after cutback is mixed with other aggregates, the volatile gets evaporated and cutback develops binding properties.
• Emulsion: Liquid product in which a substantial amount of bitumen is suspended in the finely divided condition in an aqueous medium. Function of the emulsifier is to protective coatings around the globules of the binder.
• Tar:Obtained when natural organic materials such as wood and coal destructively distilled in the absence of air. Coal tar is superior to wood tar.

Length of the curve is given by,

The tangent length of the curve is given by,

Where,
Δ = Deviation or deflection angle in degrees
Δ = 180° - Angle of intersection
R = Radius of the curve in m
Given,
R = 200 m, Δ = 60° 

Given:
SL = 20%
PL = 40%
V_P = 1.2 V_d
V_L = 1.5 V_d

Now, putting values, we get 

Hence, the plasticity Index Pl of the soil is 30%.

Slenderness ratio(λ) of an RC column:
It is the ratio of its effective length to the least lateral dimension of the column.

According to slenderness ration column is classified as follows:

Length of transition curve on the basis of super elevation is given by:
Case 1: Rotation of pavement by inner edge:
L = N  E
Case 2 : Rotation of pavement about centres:

Where, N = Rate of Super elevation, E = Superelevation
Here, considering case 1 only:
Length of transition curve, L = 500 × 15 = 7500 cm or 75 m.
If we consider case 2 we get L = 37.5 m which is not in any option.
Hence, option ‘2’ is correct.

Given data
Φ = 0
Deviator stress (σ_d) = 60 kN/m²
Initial cell pressure or confining stress (σ₃) = 50 kN/m²
final confining pressure (σ₃') = 100 kN/m²
We know that
σ₁ = σ₃ + σ_d
where σ1 = initial principal stress
σ₁ = 50 + 60 = 110 kN/m²
σ₁ = 110 kN/m²
Also, we know that-
σ1 = σ₃tan²(45 + Φ/2) + 2C tan(45 + Φ/2)
Where C = cohesive strength of soil
110 = 50 × tan²(45 + 0) + 2C × tan(45 + 0)
110 = 50 + 2C
C = 30 kN/m²
Cohesive strength of soil is 30 kN/m²
σ₁' = σ3'tan2(45 + Φ/2) + 2C tan(45 + Φ/2)
σ1' = Final principal stress
σ₁' = 100 × 1 + 2 × 30 = 160 kN/m²
Let deviatoric stress at failure is σ_d' at failure
σ1' = σ3' +σd'
160 = 100 + σd'
σd' = 160 - 100 =60 kN/m²
σd' = 60 kN/m²
Deviatoric stress at failure is 60 kN/m².

Stokes Law
Assumptions

• It is assumed that particles show discrete settling (i.e. grains of different sizes fall through a liquid at different velocities).
• Particles assumed spherical in shape.
• Medium is assumed infinite.
• Particles size range 0.2 mm to 0.0002 mm.

Hooke’s Law states that within the limit of elasticity, the stress induced (σ) in the solid material due to some external force are directly proportional with the strain (ε ) in that material.  In other words, stress and strain are linearly related to each other.  
As per Hook’s Law,
σ  ∝ ϵ
or
σ = E ϵ
Where, E is called constant of proportionality or Young’s Modulus of Elasticity.
The working stress method of design is based on Hooke’s Law.
Note:
The main difference between working stress and limit state method of design is given below:

In the case of CPM analysis, the total project cost is the sum of indirect cost and direct cost. 
Indirect cost:

• The indirect cost of a project includes overhead cost, losses, penality, rentals, project accommodations.
• The indirect cost is directly proportional to project duration with a linear variation. So if time is reduced then cost is also reduced.

Direct cost:

• Direct cost is the cost that is directly dependent on the number of resources involved for the completion of activities. It includes labor, materials, plants, and machining.
• To get the same work done in less time, we have to increase the amount of labor, equipment, and time-saving material that too at extra charges which simply means an increased direct cost. 

Dip:

• It is the inclination of the magnetic needle with the horizontal.
• This angle varies at different points on the Earth's surface. Positive values of inclination indicate that the magnetic field of the Earth is pointing downward, into the Earth and negative values indicate that it is pointing upward. 
• At the magnetic equator, the dip needle rests horizontally at an angle of zero degrees while, at the magnetic poles, the magnetic needle rests vertically, at an angle of 90 degrees.
• At all the other places, the angle of dip is between 0 and 90 degrees.

Gantt Chart

• These are mainly used to allocate resources to activities.
• The resources allocated to activities include staff, hardware, and software.
• These are useful for resource planning.
• It is a special type of bar chart where each bar represents an activity.
• The bars are drawn along a timeline.
• The length of each bar is proportional to the duration of time planned for the corresponding activity, so it represents the production schedule.

Chlorination:
Chlorination is used for: Disinfection, control of microorganisms, removal of ammonia, control of taste and odour, destruction of organic matter, hydrogen sulphide oxidation.
Types of chlorination:

1. Plain chlorination:
This term is used to indicate that only the chlorine treatment and no other treatment has been given to the raw water
It is used for clean water, i.e turbidity between 20 - 30 mg/l
Dose is 0.5 mg/l
2. Pre-chlorination:
It is the process of applying chlorine to the water before filtration or rather before sedimentation and coagulation.
Normal dose is 5 to 10 mg/l and pre-chlorination is always followed by post chlorination
3. Post chlorination:
It is the normal standard process of applying chlorine in the end, when all other treatments have been completed.
4. Double chlorination:
It simply means that the water has been chlorinated twice
5. Break-point chlorination
It means an extent of chlorine is added to water.
It represents that much dose of chlorination, beyond which any further additional chlorine will appear as free residual chlorine.
6. Super chlorination
When excess chlorine is added to water during epidemic such that it gives a residual of 1 to 2 mg/l beyond break point is called as super chlorination.
7. Dechlorination
When chlorine residue is high, excess chlorine will be removed by dechlorinating agent.
The various dechlorinating agents are:
(i) Sodium Thiosulphate (Na₂S₂O₃H₂O)
(ii) Activated carbon
(iii) Sulphur dioxide (SO₂)
(iv) Sodium bisulphate (NaHSO₃)
(v) Ammonia as NH₄OH
(vi) Sodium sulphate (Na₂S₂O₃)

The value of the building refers to the current saleable value of the Structure or the sale price of the building is called the value of the building. It may change as per market conditions i.e. it may go higher or lower than the original cost.
The valuation of the building is done for the following purpose:

• Buying or selling
• Fixation of rent
• Taxation
• Security of Loans or Mortgage
• Compulsory acquisition
• Insurance

Various type of the beam and their purpose:

Open cross-staff

• It is used to set out an offset at a right angle.

French cross-staff

• It is used for setting out an offset at angle of 45° or 90°.

Optical square

• It is used for setting out accurately the long offsets.

Adjustable cross-staff

• It is used for setting out an offset at any angle.

Part of typical construction project lifecycle till commissioning are
Pre-project Phase-

• We have to create and evaluate the project in order to determine if it is feasible and if it should be undertaken, at the beginning of the project.
• Here the project objective or need is identified; this can be a business problem or opportunity.

Planning and Design Phase-

• The planning phase involves further development of the project in detail to meet the project’s objective.
• The team identifies all of the work to be done. The project’s tasks and resource requirements are identified, along with the strategy for producing them.
• Design phase can also be known as formulation phase.

Contractor Selection Phase-

• In anticipation of selecting a contractor, the client must decide whether an open invitation will be issued to all possible vendors or whether only certain contractors will be invited to submit offers and whether any sort of pre-qualification process will be invoked to limit the number of tenders.

Project Mobilization Phase-

• The process of obtaining materials and equipment to be incorporated into the project must be initiated and arrangements for labor, the other essential resource, must be organized.
• With the completion of this phase, it is finally time to begin the actual field construction.

Construction Phase-

• This is the implementation phase, where the project plan is put into motion and the work of the project is performed practically on site. It is essential to maintain control and communicate as needed during each implementation stages.

Performance and Monitoring Phase of Construction Project

• This stage is all related to the measurement of progress and performance to make sure that items are tracking with the project management scheduling. This phase regularly happens at the same time as the execution phase.

Closure Phase of Construction Project

• During the final closure, the importance is on providing the final deliverables to the customer.
• So operation and maintenance stage is a part of typical construction project lifecycle till commissioning.

As per IS 456:2000, cl.9.3.  Nominal mix concrete can be used for concrete M20 or lower.
Here, M – refers mix and 20 represents characteristics strength.
The following table 9 of IS456:2000 gives quantity of water and aggregates required for Nominal mix design.

Kinetic energy correction factor(α): 

• It is defined as the ratio of kinetic energy/second based on actual velocity to the kinetic energy/second based on average velocity.
• 
• where A = area, V= average velocity, u= local velocity at distance r.
• For laminar flow in a circular pipe α = 2  

Chlorine is more toxic to vegetation than SO₂ by a factor of 2 or 3.

Soil stabilization:
Soil stabilization aims at improving soil strength and increasing resistance to softening by water by bonding the soil particles together, waterproofing the particles, or a combination of the two.
Soil Stabilization is either achieved by Mechanical, Physical, Chemical or Physio chemical Stabilization.
Physical stabilization may be achieved by the addition of:
1. Cement stabilisation
2. Lime stabilisation
3. Bitumen stabilisation
4. Chemical stabilization
5. Resin stabilisation
Chemical stabilization may be achieved by the addition of:
1. Calcium Chloride
2. Sodium Chloride
3. Sodium Silicate
4. Polymers
5. Chrome Lignin
6. Other Chemicals, etc.

• Track ballast forms the trackbed upon which railroad sleepers are laid.
• It is packed between, below, and around the sleepers.
• It is used to bear the load from the railroad ties, to facilitate drainage of water, and also to keep down vegetation that might interfere with the track structure. 
• The ballast also holds the track in place as the trains roll over it.
• A variety of materials have been used as track ballast, including crushed stone, washed gravel, bank run (unwashed) gravel, torpedo gravel (a mixture of coarse sand and small gravel), slag, chats, coal cinders, sand, and burnt clay. 
• The term "ballast" comes from a nautical term for the stones used to stabilize a ship.

Resilience:

• The resilience of the material is the triangular area underneath the elastic region of the curve.  Resilience generally means the ability to recover from (or to resist being affected by) some shock, insult, or disturbance.
• In physics and engineering, resilience is defined as the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading to have this energy recovered.
• In other words, it is the maximum energy per volume that can be elastically stored. It is represented by the area under the curve in the elastic region in the Stress-Strain diagram. 
• This is usually measured by the modulus of resilience, which is the strain energy per unit volume required to stress the material from, zero stress to the yield stress.

Hardness:

• Hardness is the resistance to plastic deformation (e.g., a local dent or scratch). Thus, it is a measure of plastic deformation, as is the tensile strength, so they are well correlated.
• Hardness is the resistance of a material to localized deformation. The term can apply to deformation from indentation, scratching, cutting or bending.
• There are a few different hardness tests: Rockwell, Brinell, Vickers, etc. They are popular because they are easy and non-destructive (except for the small dent).

Ductility:

• The ability to deform before braking. It is the opposite of brittleness. Ductility can be given either as percent maximum elongation emax or maximum area reduction. 

Permeability:

• Permeability is the property of soil by virtue of which it allows the flow of fluid through it.
• Permeability is also termed hydraulic conductivity.
• The permeability of coarse-grained soil is competitively more than that of fine-grained soil.​​

Note:
∴ Permeability (low to high) clay < silty clay < fine sand < coarse gravel.

The below diagram show cross-section of the permanent way as per Indian Railway Standard:

Coning: Inward provision of the slope of 1:20 on the wheels of the railway wagon to counteract the centrifugal force acting the on the train. So, it enables the train wheels to cover different distances along the inner and outer curves simultaneously.

Purpose of coning:
1. To check lateral movement of wheels
2. To avoid damage to inner faces of rails
3. To avoid discomfort to passengers

The stress developed in mild steel sheets can be calculated using Hooke’s Law. Here, it is assumed that linear elastic analysis is used.
σ = P/A
Where
P is the applied axial load and A is the Cross-sectional area
Given:  175 mm wide and 10 m thick plate
Cross-Sectional Area, A = 175 × 10 = 1750 mm2
Applied axial Load, P = 23.5 kN = 23500 N
Substituting these values in the above equation, we get

σ = 13.42 N/mm²
This axial stress developed will be tensile in nature if the applied load is tensile or it will be compressive if the applied load is compressive.

Creep of rail:

• Creep is defined as the longitudinal movement of the rail with respect to the sleepers. Rails tend to gradually move in the direction of dominant traffic. 

Theories for the development of creep
1) Wave motion theory:

• According to this theory the rails have a wavy formation, as the wheels move forward, the depression also moves with them and the previously depressed portion springs back to the original one.

2) Percussion theory:

• According to this theory, creep is developed due to the impact of wheels at the rail end ahead of the joint. The continuous movement of several wheels passing over the joint pushes the facing or landing rail forward, thereby causing creep
  

Major causes for creep in rail are as follows:

• Forces developed when the train is starting or stopping by application of brakes.
  • While starting, the wheels push the rail backwards and hence the direction of creep is in the backward direction.
  • When brakes are applied then the wheels of the vehicles push the rails in the forward direction and hence the creep is in the forward direction.
• Due to wave motions developed when the wheels of the vehicle hit the crest.
• Unequal expansion/contraction due to the different temperature gradient along the track.

Excess of fluoride causes, Fluorosis which is a condition that results in white or brown speckles on your teeth. It's caused by overexposure to fluoride in the early years of life when your permanent teeth develop. It has nothing to do with dental cavities, but as per the given options, fluoride up to 1 mg/l, helps prevent cavities and can even reverse the earliest stages of tooth damage.

Pneumoconiosis is caused by workplace exposure to dusts in the air that are breathed into the lungs (inhaled).
Asbestos, silica, and coal dust are the most common causes of pneumoconiosis.
Pneumoconiosis can be prevented with appropriate protection.
So the correct option will be (B) P - 4, Q - 1, R - 3, S - 2

Compaction factor test

• This test used to assess the workability of concrete mix and more precise and sensitive than the slump test.
• It is particularly useful for concrete mixes of medium and low workabilities.
• This test is not suitable for concrete of very low workability of the order of 0.7 or below.

Note: Each test, therefore, is carried out at a constant time interval after the mixing is completed if strictly comparable results are to be obtained. A convenient time of releasing the concrete from the upper hopper has found to be 2 min after the completion of mixing.