Quick Revision of Civil Engineering - Test-3

Quick Revision Test 3

Civil Engineering

Followings are the classification of secondary treatment units:

:

S.No.	Method	Contact Mechanism	Decomposition
1	Trickling filter	Attached growth	Aerobic
2	Rotating biological contactor	Attached growth	Aerobic
3	Activated sludge process	Suspended growth	Aerobic
4	Oxidation pond	Suspended growth	Aerobic
5	Septic tank	Suspended growth	Anaerobic
6	Imhoff tank	Suspended growth	Anaerobic

Super Elevation 

According to IRC,

Maximum Superelevation
Plain & Rolled Terrain	7 %
Hilly Terrain	10%
Urban Roads	4%

Coefficient of uniformity Cu:
It is defined as the ratio of D60­ to D­10. When Cu ≈ 1 uniformly graded soil. When Cu>4 well-graded gravel When Cu>6 well-graded sand.
Here, D60 = 60% particles are finer than this size, D10 = 10% particles are finer than this size.

.

Basic Runway length	It is the length of runway under the following assumed conditions at airport- Airport at sea level Standard temp at airport is 15℃ No wind is blowing Runway is levelled in longitudinal direction Aircraft is loaded at its full loading capacity The basic runway length is determined in three cases- Normal landing case – aircraft should stop within 60% of landing distance or runway length Normal take off case – minimum clearway width should be 150m and it is also kept free from obstructions. Engine failure case – In this case, basic runway length may consider either clearway or stopway or both.
Runway capacity	The ability of a runway system to accommodate aircraft landing and take off. It is usually expressed in operation per hour or operation per year.
Runway geometric design	The following items are to be considered in geometric design of runway- Runway length Runway width Width and length of safety area Transverse gradient Longitudinal and effective gradient Rate of change of longitudinal gradient Sight distance
Hanger	It is the covered area for repair and servicing the aircraft Hanger depends upon the size of aircraft and turning radius Number of hangers depends upon peak hour per volume of aircraft

Duty: It is the number of hectares of land irrigated for full growth of a given crop by a supply of 1 cumec of water continuously during the entire base period of that crop.

Duty of water changes from place to place, it will be maximum at the field and minimum at the head of the main canal.

Duty is the area that can be irrigated by the discharge of 1 cumec of water.

At the head of the canal, there are numerous losses to occur later which requires more amount of water to irrigate a particular field. However, if considered on the field, all losses have already occurred and a lesser amount of water is required to irrigate the same considered area.

Valuation of a property may be prepared by different methods as follows:

a) Rental method of valuation ⇒ Suitable for a property with the new building

b) Land and building method of valuation ⇒ Suitable for special purpose properties such as schools, police stations, etc

c) Capital value method ⇒ Suitable for open land, clubs, out homes, etc

d) Profit-based valuation ⇒ Suitable for shops, hotels, cinemas, etc

e) Development method of valuation ⇒ Suitable for an underdeveloped property

f) Amortisation method ⇒ it is based on dynamic allocation table.

Comparison of the allowable grade of railway and highway:

1. Maximum allowable graded are lower for railways than for highways due to steel wheel on steel rails have lower frictional co-efficient than rubber tyres on pavements.

2. Maximum allowable grades are lower for railways than for highways because the construction cost becomes prohibitive for the railways at high grades.

3. Higher grade in railways is avoided due to the high traction effort required and you might have seen two engines pulling the whole train on high grades.

They are covered in Articles 12 to 35 in the Constitution.

 

1 Right to Equality

2 Right to Freedom

3 Rights against Exploitation

4 Right to Freedom Of Religion

5 Cultural And Educational Rights

6 Right To Constitutional Remedies

Vertical Deflection limits for industrial buildings as per IS 800:2007 are:

a) For Purlins and Girts subjected to live load/wind load supported on elastic cladding, maximum deflection is limited to span / 150.

b) For Purlins and Girts subjected to live load/wind load supported on Brittle cladding, maximum deflection is limited to span / 180.

Rise and Fall Method:

It provides an arithmetic check on Back sights, intermediate sights and fore sights.

It is adopted whenever the number of intermediate stations is less and also if the number of shifting of instruments is more

The difference between the levels of consecutive staff points is calculated

Generally used for fly leveling, profile leveling or to establish BMs

Checks: ∑BS - ∑FS = Last R.L – First R.L = ∑Rise - ∑Fall

Standard penetration test is a simple and low - cost testing procedure widely used in the geotechnical investigation to determine the relative density and angle of shearing resistance of cohesionless soils and also the strength of stiff cohesive soils.

The California bearing ratio test is meant for the evaluation of subgrade strength of roads and pavements.

Plate bearing test is used to evaluate the supporting power of subgrade for use in pavement design by using large diameter plates.

Triaxial compression test is used to determine shear strength of soil sample under lateral confinement

As per IS 800:2007, The maximum slenderness ratio for a member normally acting as a tie in a roof truss or a bracing system but subjected to possible reversal of stresses resulting from the action of wind or earthquake forces will be 350.

Cant brick

1. It is used for door and window jambs. The double cant brick is used for octagonal pillars.

2. It is a non-standard (special) brick with slope or angle cut across the head of the brick.

3. These bricks are sometimes used to change the direction of brickwork.

4. It allows brickwork to turn through 30, 45 and 60° angles on plan, with variations in leg dimensions to achieve different bond pattern requirements.

5. Cant specials allows chamfer detailing to be achieved within brickwork to doors, windows and corner details as well as other locations.

The volume of water evaporated (V) = E × L × B

Where, E = Evaporation measured per day, L = Stretch of evaporation  & B = Average surface width

Based on Alignment Canals are classified into 3 categories. These are:

1. Ridge Canal, 2. Contour Canal and 3. Side Slope Canal
Their characteristics are given below:

:

Ridge Canal ( Watershed canal)	Contour Canal ( Single Bank Canal)	Side Slope Canal
Aligned along the ridge or natural watershed Line	Aligned along the natural contour of the country	Aligned perpendicular to the contour of the country.
No Cross-Drainage work required	Maximum cross drainage work is required	No Cross Drainage work required.
Can irrigates on both sides of the ridge and hence, a large area can be cultivated	Can irrigate areas only on one side	Can irrigate areas only on one side

As per IS 456: 2000, CL 21.0, following should be remembered for fire resistance in respect of beam and floors.

.

Fire Resistance	Minimum width of Beam	Minimum thickness of Floor
For 1 hr fire Exposure	200 mm	95 mm
For 1.5 hr fire Exposure	200 mm	110 mm
For 2 hr fire Exposure	200 mm	125 mm
For 3 hr Fire Exposure	240 mm	150 mm
For 4 hr Fire Exposure	280 mm	170 mm

Efflorescence: This is caused because of alkalies present in bricks. When bricks come in contact with moisture, water is absorbed and the alkalies crystallize. After drying, grey or white powder patches appear on the brick surface.

The degree of efflorescence is given as:

(a) NIL – When there is no perceptible deposit of efflorescence.

(b) SLIGHT- Not more than 10% area of the brick covered with a thin deposit of salt.

(c) MODERATE- Covering up to 50% area of the brick.

(d) HEAVY- Covering 50% or more but unaccompanied by powdering or flacking of the brick surface.

(e) SERIOUS- When there is a heavy deposit of salts accompanied by powdering and/or flacking of the exposed surfaces.

Different types of efficiency are as follows:

i) Water conveyance Efficiency (ηo)

ηo=WaterdeliveredWaterdiverted×100${\eta }_{\mathrm{o}}=\frac{\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{d}\mathrm{e}\mathrm{l}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{r}\mathrm{e}\mathrm{d}}{\mathrm{W}\mathrm{a}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{d}\mathrm{i}\mathrm{v}\mathrm{e}\mathrm{r}\mathrm{t}\mathrm{e}\mathrm{d}}\times 100$

Major lower during conveyance are seepage and percolation.

ii) Water application efficiency (ηo)

ηo=WaterstoredWaterdelivered×100

Major losses in application are runoff losses and deep percolation.

iii) Water use efficiency (ηs)

ηo=Waterusedbenefically+LeachingWaterdelivered

iv) Water storage efficiency (ηs)

ηs=WaterstoredWaterrequiredtobringwatercontenttoFC

v) Consumptive use efficiency (ηco)

ηcv=NormalconsumptiveuseNetamountofwaterdepeleted

vi) Distribution efficiency (ηd)

ηd=(1−ydym)×100

Where yd = Average numerical deviation of depth of water stored/penetrated and ym = Mean depth of water penetrated.

:There are mainly two methods (Indore and Bangalore method) adopted in India for decomposition of Solid wastes generated. The main difference between Indore Method and Bangalore Method for decomposition of MSW is given below:

Indore Method	Bangalore Method
Decomposition of MSW by composting is done aerobically.	Decomposition of MSW by composting is done an-aerobically.
Decomposition takes 2-3 Months	Decomposition takes 5-6 Months
Mixing is ensure either Mechanically or manually	No mixing is done.

The characteristics of under reinforced section and over reinforced section when compared with balanced section are given below in tabulated form.

Under – reinforced section when  compared  with Balance section	Over – reinforced section when compared  with Balance section
Steel yield first then concrete	Concrete will reach to maximum stress first
Reinforcement is less than a balanced section	Reinforcement is more than a balanced section
Primarily tension failure	Primarily Compression  failure
Ductile failure	Sudden or brittle failure
Depth of Neutral axis shifts upward i.e. it is less than that of balanced section (Xu < Xu,lim)	Depth of Neutral axis shifts downward i.e. it is more than that of balanced section (Xu > Xu,lim)
Strain in steel is greater than that of in balanced section.	Strain in steel is less than that of in balanced section.
Larger section  is required because it has less steel	Smaller section is required because it has more steel.
More deflection because it has less steel	Less deflection because it has more steel.
Moment of Resistance is less than that of Balanced section	Moment of Resistance is more than that of Balanced section

Moment of inertia of different section:

S.No.	cross-section	INA	Ymax	Z
1	Rectangle	I=bd312$I=\frac{b{d}^{\mathrm{3/}}}{12}$	Ymax=d2$Y_{max}=\frac{\mathrm{d/}}{2}$	Z=bd26$Z=\frac{b{d}^{\mathrm{2/}}}{6}$
2	Circular	I=π64D4$I=\frac{\mathrm{\pi /}}{\mathrm{64 }}{D}^4$	Ymax=d2$Y_{max}=\frac{\mathrm{d/}}{2}$	Z=π32D3$Z=\frac{\mathrm{\pi /}}{\mathrm{32 }}{D}^3$
3	Triangular	I=Bh336$I=\frac{B{h}^{\mathrm{3/}}}{36}$	Ymax=2h3$Y_{max}=\frac{2\mathrm{h/}}{3}$	Z=Bh324$Z=\frac{B{h}^{\mathrm{3/}}}{24}$

For circular cross-section,

Ixx=Iyy=πD464$I_{xx}=I_{yy}=\frac{\pi D^4}{64}$

According to perpendicular axis theorem,

Izz = Ixx + Iyy

∴ Izz = 2 × Ixx

∴ Ixx is always less than Izz

The line joining the points of equal rainfall depth called isohyetal lines.

Thiessen polygon is constructed by perpendicularly bisecting the sides of the triangle formed by joining the rain gauges through straight lines. This method used to determine the average rainfall over the given area.

Isobar is a line on a map connecting points having the same atmospheric pressure at a given time.

Mass curve is the graph between accumulated rainfalls against time.  It is used to determine the total amount of rainfall that occurred in a particular area. 

Quantity of Plastering work is calculated in square metres.

Following are the conditions for deduction of openings :-

1. No deduction are made for ends of beams, rafters, posts, etc.

2. No deduction are made below 0.5 sq m opening area.

3. Deduction are made on one face of wall if opening area is from 0.5 sq m to 3 sq m.

4. Deduction are made on both face of wall if opening are is more than 3 sq m.

∴ Deduction of opening for 2 m2 is allowed for one face of the wall.

IS: 3461-1966: Indian standard specification for PVC (Vinyl) asbestos floor tiles.

IS 1464-1969: Clay ridge and ceiling tiles-Specification

IS 6165-1971: Dimensions for special shapes of clay bricks.

IS 3951-1975: Hollow clay tiles for floors and roofs.

Condition for Maximum Discharge for Circular Section:

α = 154° = 2.65 radians

D = 0.95 d

Rm = 0.29 d

Wetter perimeter = 2αr = αd = 2.65 d

Condition for Maximum Velocity for Circular Section:

α = 128.75° = 2.25 radians

D = 0.81 d

Rm = 0.3 d

Scrap Value: Scrap Value is the sell value of dismantled materials of an asset at the end of its useful life. Scrap Value is counted in the calculation of depreciation of a property, generally @10% of the cost of the structure.

Important Points:

Salvage value: Salvage Value is the Estimated Value of an asset without dismantling it at the end of its useful life.

Book Value: Book value is the amount shown in the account book after allowing necessary depreciations. The book value of a property at a particular year is the original cost minus the amount of depreciation allowed per year and will be gradually reduced year to year and at the end of the utility period of the property, the book value will be only scrap value.

Market Value: The market value of a property is the amount that can be obtained at any particular time from the open market if the property is put for sale. The market value will differ from time to time according to demand and supply.

Temporary spurs or bunds are temporary structures constructed every year after floods. A bund is a structure made to project flow from a riverbank into a stream or river with the aim of deflecting the flow away from the side of the river on which the groyne is built.

Important Points:

Bunds are temporary in nature whereas Weirs and barrages are permanent in nature.

In a weir, the water overflows the weir, but in a dam, the water overflows through a special place called a spillway. Weirs have traditionally been used to create mill ponds.

A barrage is a weir that has adjustable gates installed over top of it, to allow different water surface heights at different times.

Different types of glasses, its constituents and applications are as follows:

Type Constituents Applications

Potash lead glass (Flint glass)

Fusion of Silica, Potash and Lead

Cut glass

Electric glasses and lenses

Prisms

Soda lime glass (Soda ash glass/ Window glass)

Fusion of Silica, Lime, Soda and Alumina

Doors

Windows

Bottle glass

(Common glass)

Sodium silicate, Calcium silicate and Iron silicate

Household bottles

Medicine bottles

Borosilicate bottles (Pyrex glass)

Fusion of Silica, Borax, Lime and Feldspa

Laboratory equipment

Day work: Day work is a means by which a contractor is paid for specifically instructed work on the basis of the cost of labour, materials and plant plus a mark up for overheads and profit. It is generally used when work cannot be priced in the normal way.

Provisional sum: A provisional sum is an allowance (or best guess), usually estimated by a cost consultant, that is inserted into tender documents for a specific element of the works that is not yet defined in enough detail for tenderers to accurately price.

Lump sum amount: It is the amount of construction of a specific work with all its contingencies, to complete it in all respect within a specified time for fixed amount.

Prime cost: it is the sum of the direct cost of materials and labour associated with a Construction Project.

The permissible design stresses for an RCC Column under different conditions are given below:

1. If minimum eccentricity is considered to be Zero i.e. emin = 0

a. Permissible axial compressive stress in concrete = 0.45 fck

b. Permissible axial compressive stress in steel = 0.75 fy­

2. If minimum eccentricity effect is considered: 

a. Permissible axial compressive stress in concrete = 0.4 fck

b. Permissible axial compressive stress in steel = 0.67 fy­

To identify the zero force members in truss, the following rules are required to be used:

1. If at a joint three members are meeting, two of which are collinear then force in third member is zero provide that no external load is acting on joint.

2. If two non-collinear members are meeting at joint and no external load is acting on that joint, then force in both members is zero.

Contour:

Contour lines are the lines joining the points of equal elevation on the ground surface.

Contour interval on map sheet denotes the vertical distance between two successive contour lines.

Characteristics of the contour lines are:

Two contour lines do not intersect each other except in the case of an overhanging cliff and a cave penetrating a hill.

All lines close themselves within the map boundaries or outside it.

Contours lines cross a valley or ridgeline at 90°.

If the contour lines are very close to each other, this indicates a steep slope.

If the contour lines are at a very large distance to each other, this indicates a gentle slope.

If the closed lines have higher elevation in the center then it represents the hill or mountain.

If the closed line have increasing elevation as we move away, then it represents a pond or a depression in the ground profile.

The direction of the steepest slope is along the shortest between the contours.

 

The contour interval depends upon the following factors:

Scale of the Map: If the scale is small, the contour interval is kept large and vice versa so as to avoid overcrowding of contours.

Purpose of Map: The contour interval selected should be small so that the map serves the intended purpose.

Nature of Ground: For a flat ground the interval is kept small and for a steep slope the interval is kept large.

Time and Funds: Contour interval is kept large when time and funds are less.

Ogee Fall:

In this type of fall, an ogee curve (a combination of convex curve and concave curve) is provided for carrying the canal water from higher level to lower level.

This fall is recommended when the natural ground surface suddenly changes to a steeper slope along the alignment of the canal.

There is a heavy drawdown on the u/s side resulting in lower depth, higher velocities and consequent bed erosion.

Kinetic energy is not well dissipated due to smooth transition.

Rapid Fall

The rapid fall is suitable when the slope of the natural ground surface is even and long. It consists of a long sloping glacis with longitudinal slope which varies from 1 in 10 to 1 in 20. It is nowadays obsolete.

Stepped Fall

Stepped fall consists of a series of vertical drops in the form of steps. This fall is suitable in places where the sloping ground is very long and requires long glacis to connect the higher bed level with lower bed level.

This fall is practically a modification of the rapid fall. The sloping glacis is divided into a number of drops so that the flowing water may not cause any damage to the canal bed. Brick walls are provided at each of the drops.

PVC pipes are becoming popular day by day due to the following advantages:

Good insulation properties

Permits high, smooth and undiminished flow of water

No problems of incrustation

Have high Hazen Williams constant and it results in smaller sizes of PVC pipes as compared to other materials

Economical and resistive to various chemical attacks

 

Disadvantages of PVC pipes are as follows:

Liable for creep and requires closer spacing when placed on grounds

They cannot resist high temperature as they are basically thermo-plastic

Lesser strength as compared to cast-iron or galvanized iron

They possess a higher coefficient of expansion as compared to other materials

Conjugate Beam Method: This method is defined as the imaginary (or conjugate) beam with the same dimensions (length) as that of the original beam but load at any point on the conjugate beam is equal to the bending moment at that point divided by EI. This is a method of analysis of determinate structure.

According to this method a hinged, roller, fixed, free and intermediate support in real beam is transformed as hinged, roller, free, fixed and internal hinge in conjugate beam respectively.

The shear force in the conjugate beam at a point is a slope at the point in the real beam. The bending moment in the conjugate beam at a point is the deflection at the point in the real beam.

Conjugate beam can be made by changing the supports

s

Real beam	Conjugate beam
Fixed support	Free support
Free support	Fixed support
Roller support	Hinge support
Hinge support	Roller support

Positive displacement pump:

Positive displacement pumps are those pumps in which the liquid is sucked and then it is pushed or displaced to the thrust exerted on it by a moving member, which results in lifting the liquid to the required height.

Reciprocating pump, Vane pump, Lobe pump are the examples of positive displacement pump whereas the centrifugal pump is the non-positive displacement pump.​

Traffic density is the no of vehicles present in one km length of road. In this case, 40 Vehicles are present on 1 km stretch of road, so

Traffic Density, k = 40 veh/km

Traffic Volume is the no of vehicles that can be passed through a particular section of road during a given period of time. The time period may be hours, minutes, seconds, days or weeks or any other as per the requirement. Generally, it is expressed in Veh/hr, if time period chosen is hours.

Basic Traffic capacity is the maximum possible no of vehicles that can be passed through a particular section of road during a given period of time under most ideal conditions. It is given as:

QB=1000s×V

Where

S is the space head way in ‘m’

QB is the Basic Traffic Capacity in Veh/hr

V is the Traffic Speed in km/hr

Design or Practical Traffic capacity is the maximum possible no of vehicles that can be passed through a particular section of road during a given period of time during the prevalent conditions on the road. It is always less than or equal to Basic Traffic Capacity.

Note:

The relation between traffic volume (Q), traffic density (K) and traffic speed (V) is given as:

Q = K × V

Method of analysis of indeterminate structures:

In the force method of analysis:

Primary unknown forces in the members and compatibility equations are written for displacement and rotations (which are calculated by force-displacement equations) in this method.

Solving these equations, redundant forces are calculated. Once the redundant forces are calculated, the remaining reactions are evaluated by equations of equilibrium.

In the displacement method of analysis:

Primary unknowns are the displacements and initially, force-displacement relations are computed and subsequently, equations are written satisfying the equilibrium conditions of the structure in this method. After determining the unknown displacements, the other forces are calculated satisfying the compatibility conditions and force-displacement relations.

Difference between Force & Displacement Methods

Force Methods	Displacement Methods
Types of indeterminacy: Static Indeterminacy	Types of indeterminacy: Kinematic Indeterminacy
Governing equation: Compatibility Equations	Governing equations:  Equilibrium Equations
Force displacement relations: Flexibility matrix	Force displacement relations: Stiffness matrix
Example: 1. Method of consistent deformation 2. Theorem of least work 3. Column analogy method 4. Flexibility matrix method 5. Castigliano’s Theorem- II	Example: 1. Slope deflection method 2. Moment distribution method 3. Kani’s method 4. Stiffness matrix method 5. Castigliano’s Theorem- I

In constant rate depreciation method, the Salvage value of any asset after end of its use full life is given as

SV = FC (1-K)N

Where

N is the design life

FC is the first Cost or Initial Value

SV is the Salvage value

K is the rate of Depreciation

Further, Book Value after ‘m’ years of depreciation is given as:

BV = FC (1-K)M

Total depreciation after ‘m’ years = FC- BV

---

g

Layout of Distribution System:

Pipes except the service connections are usually made of cast iron with some type of coating to avoid rusting where as foe service connection galvanised iron pipes are used.

Dead end system: Also known as tree system, it has one main pipe from which various submains bifurcate and from submains, laterals comes out.

It is easy to design, cheap and simple but due to dead ends, free circulation of water is prevented.

Grid-iron system: Here the mains, branches and laterals are interconnected hence dead ends are eliminated and water can reach to a location through more then one route. Pressure throughout the grid system is equal.

Ring system: It has main pipe all over the area. Thus, it has smaller branches and laterals, and has lesser number of valves. Hence cheaper as compared to grid system.

Radial system; A big area is divided into several zones and at the centre of each zone, a distribution reservoir is kept. Thus it has zonal distribution.

1. Full reservoir Level:- The full reservoir level is the highest water level to which the water surface will rise during normal operating conditions.

2. Maximum water level:- The maximum water level is the maximum level to which the water surface will rise when the design flood passes over the spillway.

3. Minimum pool level:- The minimum pool level is the lowest level up to which the water is withdrawn from the reservoir under ordinary conditions.

4. Dead Storage:- The volume of water held below the minimum pool level is called the dead storage. It is provided to cater for the sediment deposition by the impounding sediment laid in water. Normally it is equivalent to the volume of sediment expected to be deposited in the reservoir during the design life reservoir.

5. Live/Useful Storage:- The volume of water stored between the full reservoir level and minimum pool level is called useful storage. It assumes the supply of water for a specific period to meet the demand.

6. Bank Storage:- It is developed in voids of soil cover in the reservoir area and becomes available as seepage of water when water levels drops down. It increases the reservoir capacity over and above that given by elevation storage curves.

7. Valley storage:- The volume of water stored by the natural river channel in its valley up to the top of its banks before constructing of a reservoir is called the valley storage. The valley storage depends upon the cross-section of the river.

8. Flood/Surcharge storage:- It is storage contained between maximum reservoir level and full reservoir levels. It varies with the spillway capacity of the dam for a given design flood.

Solid wastes can be categorized in the following 3 categories:

Municipal wastes: These include food wastes, rubbish, ashes and residues, demolition and construction waste, treatment plant waste and some special wastes.

Industrial wastes: Wastes arising from industrial activities and it typically includes rubbish, ashes, demolition and construction wastes, hazardous wastes and some special wastes.

Hazardous wastes: Wastes that pose a substantial danger immediately or over a period of time to human, plant or animal life. They can be radioactive substance, chemicals, biological wastes, flammable wastes and explosives.

As per CPCB (Central Pollution Control Board)

Solid waste generated in small cities …………… 0.1 kg per capita per day

Solid waste generated in medium cities ………… 0.3-0.4 kg per capita per day

Solid waste generated in large cities …………… 0.5 kg per capita per day

Red means “STOP”, green means “Go”, and yellow means “hurry up and make that damn light”.

Red symbolizes dander in many cultures, which make sense, considering it has the longest wavelength and low frequency of any colour on the visible spectrum, meaning you can see it from a greater distance than other colours.

Green role in lights has actually changed dramatically over time. Its wavelength is shorter than yellow on the visible spectrum, meaning it is still easier to see than any colour other than red and yellow.

High volume fly ash concrete is a concrete where a replacement of 50 to 60 percentage of cement is made with the usage of fly ash. This fly ash may be mixed at the time of cement clinker formation or can be added in concrete as an admixture.

The followings are some characteristics of High Volume Fly ash Concrete:

1. Low heat of hydration and thermal shrinkage.

2. Longer Curing period. Minimum of 7 days of moist-curing is required.

3. Resistance to corrosion, resistance to alkali aggregate reaction, resistance to sulfate attack.

4. Properties like compressive strength, flexural strength, modulus of elasticity and split tensile strength are improved.

5. Applications: Dam Construction, Pavement Construction. 

The leaseholder is known as the lessee and holds the physical possession of the property for a definite period under terms and condition specified in the lease document.

Other forms of the lease are as follows:

Building Lease: In this type of lease, the owner of a freehold open plot of land let out his land to the lessee on an agreed amount of premium or ground rent or a combination of both.

The leaseholder may then erect a building over there up to a specified amount and within a specified time and he maintains the property and can reside or earn income through such property.

Occupational Lease: In this type, the lease is granted against premium or rent or a combination of the two by an owner of property consisting of land and building or other structures for occupancy for a fixed period to another person.

Sublease – A leaseholder may render sub-lease of his leasehold property to other persons subject to the terms and conditions in the original lease and be allowed by Local regulations or Court of Law.

Perpetual Lease – When the lease of a property is given for a number of years providing a condition that lease is renewable time to time, even for endless time according to the desire of the leaseholder.

When a lease is granted for a period of 99 years, it is known as long term lease and when it is for 999 years it is said to be perpetuity or for an endless duration.

A short-term lease generally refers to a lease with a duration of fewer than six months. Often, they are based on a month-to-month rental agreement, which may or may not is renewed at the end of each month.

The following should be remembered while measuring the roof covering  as specified in IS 1200- 1973; Part 9 covers the method of measurement of roof covering (including cladding) for buildings and civil engineering work:

1. Portions of roof covering overlapped by ridge or hip, etc, shall be included in the measurements of the roof.

2. Any opening not exceeding 0·4 sq.m shall not be deducted and forming such openings requiring cutting shall be enumerated.

3. Any opening exceeding 0.4 sq.m shall be deducted and cutting required shall be measured in running meters.

4. Cutting across corrugations shall be measured on the flat.

5. No additions shall be made for laps cut through.

6. Sheeting curved or bent to curvature shall be measured separately.

7. The woodwork and steelwork shall be measured separately.