JKSSB JE Civil Mock Test - 1 - Civil Engineering (CE) MCQ

Whole circle Bearing system:

• In this system, the bearing of the line is measured from the north in clockwise direction.
• Thus whole circle bearing system (WCB) of a line is the horizontal angle which the line makes with the north end of the reference meridian.
• The WCB of a line can vary from 0° to 360°.

Quadrantal Bearing system:

• The quadrantal bearing (QB) of a line is the acuate angle which the line makes with the meridian.
• Quadrantal bearing is measured either from north end or south end as the case may be i.e. whichever is nearer to the line. The quadrantal bearing of a line can vary from 0° to 90° 

Conversion table for WCB and QB:

Given, 
Reduced Bearing = N87°W 
∵ Reduced bearing exists in the 4th coordinate, so WCB of line
WCB = 360 - 87° = 273° 

Given structure in below figure:

Now draw the free body diagram of point B

Hence, apply the equilibrium for forces in the vertical direction 

Samples for design of waste water treatment plants:

• GRAB SAMPLE:- one sample is taken from one point and time.
• INTEGRATED SAMPLE:- the combination of grab samples collected at the same time but at different locations.
• COMPOSITE SAMPLES:- multiple samples taken from one point at multiple times and integrated together for analysis.

So composite samples is relatively employed for the design of waste water treatment plants.

Manholes are masonry or RCC chambers provided at suitable intervals along the sewer line for inspection, cleaning and maintenance of sewerage system and also to join sewer pipes.

Location of Manholes:
1. Change of Gradient
2. Every bend
3. Every junction
4. Change of Sewer diameter
As per IS 1742:1960:
The recommended spacing of manholes on straight reaches of sewer lines for the diameter of sewer greater than 1.5 m is 300 m.

Equilibrium is mainly of 3 types.

Stable Equilibrium:

• If a system originally in equilibrium is disturbed and then able to restore to its initial equilibrium configuration, then it is a case of stable equilibrium. 
• In stable equilibrium restoring torque always opposes the disturbing torque.
• A ball lying on a curved surface is an example of stable equilibrium.

Unstable Equilibrium:

• If a system originally in equilibrium moves to a new position on disturbing and is unable to restore its initial equilibrium position, then it is an unstable equilibrium.
• In unstable equilibrium restoring torque always supports the disturbing torque.
• A ball lying on a convex surface is an example of unstable equilibrium.

Neutral Equilibrium:

• If a system is in equilibrium and adopts a new position due to a slight disturbance, then it is a neutral equilibrium.
• A ball lying on the horizontal plane is an example of neutral equilibrium. 

Wavy Equilibrium is not a type of equilibrium.

Check rails/guard rails are introduced on curves and special layouts to facilitate the operation of multi‐axle rigid frame vehicles with long axle base since these vehicles had a tendency of an outer wheel climbing the rail.
The objective behind providing check rails was to:
(i) Prevent derailment due to flange climbing
(ii) Reduce rail wear of high rail
(iii) Improve vehicle curving performance
Check rail should be provided on curves where the radius is 218 m or less on BG (Broad Gauge), 125 m or less on MG (Metre Gauge) and 190 m or less on SG (Standard Gauge).

Irrigation Efficiencies:
(i) Water Conveyance Efficiency, (η_c)

where, W_f = Water delivered to the field 
W_r = Water delivered from the reservoir
(ii) Water Application Efficiency (η_a)

where, W_s = Water stored in the root zone 
W_f = Water delivered to the field
(iii) Water use Efficiency (η_u) 

where, W_u = Water use consumptively. 
W_f = Water delivered to the filed
(iv) Water storage Efficiency (η_u)

where, W_s’ = Actual water stored in the root zone
W_f = Water needed to store to bring the water content up to field capacity.
(v) Water distribution Efficiency, (η_d) 

where, y = Average numerical deviation in the depth of water stored from the average depth of irrigation stored
d = Average depth during irrigation
(vi) Consumptive use Efficiency (η_cu) 

where, W_cu or C_u = Water used by plant consumptively. 
W_d = Net amount of water depleted from root zone.

The various features of concrete stress block considered by IS 456:2000: for limit State Design are shown below figure:

1. Design compressive strength of concrete = 0.45 f_ck
2. Maximum compressive force resisted by concrete, C = 0.36 (sec B x_cu)
3. This force well act at a distance of 0.42 x_cu from top fibre of concrete.
4. Maximum strain in concrete at top fibre is 0.0035 and at point up to which stress block is uniform is 0.002.
5. Depth upto which concrete streets block is uniform is (3/7)x_cu, measured from top fibre.
6. Depth upto which concrete streets block is parabolic is (4/7)x_cu, measured from N.A.
7. Area of stress block = Area of rectangular block + area of parabolic block = 0.36 f_ck x_cu

Development of Roads: Roman Method → Tresguet Design → Metcalf Design → Telford Design  → Macadam Design  → C.B.R Method → Modified C.B.R Method
Macadam Construction: This was the first method of scientific construction where the top layer was provided with higher strength compared to the bottom. A curved surface for the pavement with a slope of 1 in 36 along with side drains was recommended.

Tresaugate (1764): He has proposed sloped shoulder with linear slope followed by side chains. The maximum thickness of this road was limited to 30 cm. The surface of such road was provided with very fine materials.

Telford Construction: Although he had not recommended any drains alongside the pavement, he was first to advise the provision of slope in the pavement surface. The thickness varies from 17 cm at the end to 22 cm at the center for foundation stress. The wearing course in his design was provided with very fine material for about 4 cm thickness.

C.B.R Method: This method has recommended the construction of pavement in numerous layers with each layer having a definite role/function in stress distribution and its resistance. This was the first method to consider the traffic volumes in the design of pavement.

Quality assurance:

• Quality assurance is defined as part of quality management focused on providing confidence that quality requirements will be fulfilled.
• The confidence provided by quality assurance is twofold internally to management and externally to customers, government agencies, regulators, certifiers, and third parties.
• It is also defined as "all the planned and systematic activities implemented within the quality system that can be demonstrated to provide confidence that a product or service will fulfill requirements for quality.

Quality Control:

• It is the process of setting standards and testing to make sure that a product or service, is done as per laid down specifications.
• It is necessary to boost the customer's confidence.

Quality of design:

• The quality of the design of a product is concerned with the tightness of specifications for the product or service.

Quality of conformance:

• The quality of conformance is concerned with how well the product or service conforms to the quality of design.
• It refers to the extent to which a firm and its supplies can create products or services with a predictable degree of dependency and uniformity at a cost in keeping with the quality requirement determined by the study on quality of design

 Quality of performance:

• The quality of performance is considered by how well the product or service gives its performance.

The setting is the ratio of the depth of the crest level of the module below the free surface level of the distributary channel to the full supply depth of the distributary channel.
Setting =H/y
For the wide trapezoidal channel, the discharge, Q is proportional to y^5/3
therefore, n= 5/3 
For orifice type outlet,
m=1/2.
For adjustable proportional module

Cant or Superelevation: It is the amount by which one rail is raised above the other rail.
It is positive when the outer rail on a curved track is raised above inner rail and is negative when the inner rail on a curved track is raised above the outer rail.
Other Important Terms:
Cant deficiency: Cant deficiency occurs when a train travels around a curve at a speed higher than the equilibrium speed. It is the difference between the theoretical cant required for such higher speed and actual cant provided.
Cant excess: Cant excess occurs when a train travels around a curve at a speed lower than the equilibrium speed. It is the difference between the actual cant and the theoretical cant required for such a lower speed.
Cant gradient and cant deficiency gradient: It indicates the amount by which cant or deficiency of cant is increased or reduced in a given length of transition e.g. 1 in 1000 means that cant or deficiency of cant of 1 mm is gained or lost in every 1000 mm of transition length.
Rate of change of cant or Rate of change of cant deficiency: It is the rate at which cant or cant deficiency is increased or reduced per second, at the maximum permissible speed of the vehicle passing over the transition curve, e.g. 35 mm per second means that a vehicle when traveling at a maximum speed permitted will experience a change in cant or deficiency of cant of 35 mm in each second of travel over the transition.

Ballast:
Ballast is a layer of broken stone, gravel, or any other suitable material placed under and around the sleepers to distribute the wheel loads from the sleepers to the underlying subgrade foundation. The locationof ballast along with other formation layers of rail cross-section are shown in the following diagram:

Some of the main functions of ballast are the following:

• To provide a firm and level bedded foundation for the slippers and rails to rest on.
• To protect the surface of the subgrade and to form an elastic bed.
• To transmit and distribute the loads from the sleepers to the subgrade.
• To allow for maintaining the correct track level without disturbing the railroad bed.
• To hold the sleepers in position during the passage of trains.
• To provide lateral stability to the track as a whole.

∴ Ballast is used in the Railway section to serve both as an elastic bed and foundation of the rail track.

Below are the values of slump and their usage:

Hence, it is clear that for slump value 50-100 mm the workability is medium and can be used for beams.
Important points:

• Slump of the cone is a measure of height difference of cone height and concrete from top.
• It indicates the workability of concrete (generally used for low to very high workability)
• Along with Slump cone test, Vee-Bee consistometer test and Compacting factor test is also used to determine workability.

• Boning rods:  A boning rod is an upright pole having a horizontal board at its top, forming a 'T 'shaped rod. They are used to set out horizontal lines or lines with a constant slope. They are used for the following work
  • Setting out canal excavation works, roads, and dyke construction.
  • Laying of sewer line and water supply pipeline.
• Sight Rails: It is a series of horizontal rails nailed to vertical posts of a certain height firmly embedded in the ground across the trench. They are used to check the gradient of a sewer pipe in a trench.
• Theodolite: Theodolite is used to measure the horizontal angle, vertical angle, horizontal distance, and vertical distance. With the help of these four parameters one can do the following tasks:
  • Locating points on a line
  • Finding the difference in the levels
  • Ranging or setting out the curves
  • Setting out grades
• Compass: It is used to measure the angles or bearings. When it is fitted inside theodolite, it is used to measure between the normal line and the line of sight.  

Priming:

• Priming is an operation in which the suction pipe, casing of the pump, and a portion of the delivery pipe are completely filled up by water from an outside source before starting the pump.
• In other words, Priming is the process in which the impeller of a centrifugal pump will get fully submerged in liquid without any air trap inside. It is always advisable to start the pump only after primping.
• Priming is an operation that generally that happens in the centrifugal pump.
• Priming is required in order to drive out the air voids present, which otherwise would make the operation of the pump ineffective.
• Because the pressure energy imparted by the centrifugal pump is proportional to the density of the liquid and if any air pocket exists in the casing, then only a negligible amount of pressure would be generated. This pressure might not be sufficient for the lifting of the liquid. Hence, priming becomes essential.

Gauge pressure:
Gauge pressure is the pressure relative to atmospheric pressure. Most of the pressure measuring devices are calibrated to read gauge pressure.

• Gauge pressure is positive for pressures above atmospheric pressure.
• Gauge pressure is negative for pressures below atmospheric pressure.
• Gauge pressure is zero at atmospheric pressure.

Atmospheric pressure:
Atmospheric pressure or barometric pressure is the pressure within the atmosphere of Earth. Atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point.
P_atm = 1.013 bar.
Absolute pressure:
Absolute pressure is the sum of gauge pressure and atmospheric pressure.
P_abs = P_gauge + P_atm.

A weir which the water level on the downstream side of a weir is above the crest of the weir is called a Submerged weir or Drowned weir.

• The Cippoletti weir is a trapezoidal weir, having side slopes 1 horizontal to 4 vertical.
• The purpose of the slope, on the sides, is to obtain an increased discharge through the triangular portions of the weir, which otherwise would have been decreased due to end contractions in the case of rectangular weirs.
• A type of contracted weir that is related to the rectangular sharp-crested weir is the Cippoletti weir, which has a trapezoidal cross-section with side slopes 1: 4 (H: V).

Discharge for a triangular weir is

Discharge over a rectangular weir is

Where,
Q = Discharge, C_d = co-efficient of discharge, H = Head above the bottom of notch, and θ = enclosed angle

Over-Reinforced Section:

The working stress design of over reinforced RC section:

• The percentage of steel provided is more than that provided in the balanced section. So the section is uneconomical.
• The actual neutral axis is below the critical neutral axis.
• The allowable limiting stress is reached in concrete before the steel stress reaches the limiting value.

Concentration [X] in mg/L = (Concentration [X] in mol/lt) x (Molecular weight of X) x 1000
∴ 17 = (X) x 17 x 1000
X = 10^-3 mol/lt

pH= -log [H⁺] = 11

Oxidation pond:
It is also known as stabilization ponds.
The biological treatment that causes stabilization of organic impurities in sewage by symbiotic action due to algae and bacteria in an artificially excavated earthen basin is called an oxidation pond. 
Algae in the pond provide oxygen for degradation through photosynthesis and bacteria releases carbon dioxide, ammonia, sulfates, and phosphates after the reaction.
It is an economical treatment requiring 20 – 50 days for complete waste stabilization
The type of mechanism that takes place is aerobic, as exposed to air.
Particles are under suspension.

Followings are the classification of secondary treatment units

Area of steel require, 
Where, B = Width of pavement panel in m
h = Depth of pavement in cm
W = Unit weight of concrete
σ_st = Allowable working tensile stress in steel 
Calculation:
Given,
σ_st = 1400 kg/cm², W = 2400 kg/m³, h = 24 cm, B = (7/2) m and f = 1.5

A_st = 2.16 × 10^-4 m² = 2.16 cm²

Marshall stability and flow:
(i) Marshall stability of a test specimen is the maximum load required to produce failure when the specimen is preheated to a prescribed temperature placed in a special test head and the load is applied at a constant strain (5 cm per minute). during the stability test dial gauge is used to measure the vertical deformation of the specimen. The deformation at the failure point expressed in units of 0.25 mm is called the marshall flow value of the specimen.
Graphical plot:
The average value of each of the above properties are found for each mix with the different bitumen contents. Graphs are plotted with the bitumen content on the x-axis and the following value on the y-axis.
(i) Marshall stability value
(ii) Flow value
(iii) Unit weight
(iv) Percent voids in total mix
(v) Percent voids filled with bitumen

Air content:
Air content is defined as the ratio of the volume of air to the volume of voids. It is denoted by a_c.

Porosity:
Porosity is defined as the ratio of the volume of voids to the total volume of soil. It is denoted by n. It varies between 0 and 1.

Percentage air voids:
Percentage air voids are defined as the ratio of the volume of air to the total volume of soil. It is denoted by n­­_a.

PERT is almost identical to the Critical Path Method(CPM) technique except it assumes each activity duration has a range that follows a statical distribution.

• In PERT the Normal Distribution is used for the completion time of the project.
• PERT uses three-time estimates for each activity. Basically, this means each activity duration can range from an optimistic time to a pessimistic time, and a weighted avenge can be computed for each activity.
• Because project activities usually represent work, and because work tends to stay behind once it gets behind, the PERT developers chose an approximation of the beta distribution to represent activity durations.
• The activity durations can be skewed more toward the high or low end of the data range.

• Figure (A) depicts a beta distribution for activity duration that is skewed toward the right and is representative of work that tends to stay late once it is behind.
• The distribution for the project duration is represented by a normal(symmetrical) distribution shown in figure (B).
• The project distribution represents the sum of the weighted avenges of the activities on the critical path.

Bending stress is given by 

Where M is bending moment y is the distance of fibre from the neutral axis and I is the moment of inertia of the cross-section
Given, square and circular cross-section having the same area and material subjected to same bending moment 
For the square of side a,
For circular section of diameter d, 
Now, since the area is the same, 
For square y = a/2 and for circular cross-section y = d/2

Therefore the circular cross-section will experience more flexural stress and square cross-section will suffer less flexural stress and hence will be more economical as compared to circular section.

The coefficient of Painting for wood works (Doors and windows) used in different types of work are as follows:

The major and minor principal stress on a plane for a given state of stress is calculated using the following formula:

To have σ₁ and σ₂ are of the same sign, σ₁σ₂ ≥ 0

On solving the above, we get
p₁. p₂ ≥ q²

As per IS 1200 (Part 27): 1992 in the booking of dimensions the order shall be consistent and generally in the sequence of length, breadth or width, and height or depth or thickness.
All works shall be measured net in decimal system as fixed in position as given below:
(a) Each dimensions shall be measured to the nearest 0.01 m where any dimension is more than 25 m it shall be measured nearest to 0.lm,
(b) Areas shall be worked out to the nearest 0.01 m², and
(c) Cubical contents shall be worked out to the nearest 0.01 m³.