BASIC KNOWLEDGE
IN CIVIL ENGINEERING
(PART-2)
(NR)-2
V.NARASIMHA
Basic knowledge in civil engineering
(part-2)
2020
VAVILALA NARASIMHA
DIPLOMA (GOVT POLYTECHNIC, ST. GHANPUR, WARANGAL.)
B. TECH IN CIVIL ENGINEERING.
REMEMBER FOREVER!
The speciality of this book is examples, pictures and diagrams to concern
topic is given.
This book is perspicuous one.
“Our brain will remember the things more precisely, which we have seen
it with our naked eye, rather than we imagined it.”
Imagination helps to get some idea about particular thing, but we cannot
clearly imagine how it look like, I mean, we wouldn’t get clear image of
something; this causes confusedness to our mind and finally leads to
illusion.
For instance, there is quite difference between bridge and flyover, both
serve for transportation, but what is the exact difference, and the situation
where it is used, which you can only get by visual experience.
Examples makes to gain practical experience with particular topic,
pictures make to understand clearly, and uses of particular one;
which makes to learn its applications.
Lengthy words with a greater number of pages about certain topics,
sometimes leads to uncomprehending. But examples, pictures and diagrams
clearly relevant to the topics even with small words, in the sense not
lengthy, makes you clearly understandable.
This book is distinct one when compare with the course content books.
This book main intention is to make civil engineering students to fill their
minds with basics and lock them inside.
© All rights reserved with publisher.
Any part or full of this book should not be
reproduced or transmitted by photocopying,
recording, any electronic methods & without the
prior permission of the publisher.
Preface
In the Basic knowledge in the civil engineering part-1 book, the
information regarding history, unit conversions, technical terms,
estimation of materials for concrete work etc., more than 50 topics
are given.
Actually, it is not an easy thing to describe in detail about civil
engineering, because it is not a small one, it is a “GIANT” - It is
not about a person living in a society, It’s about the world and
creators of world.
In this part -2 book some other information such as water
treatment process, sewers, hydration of cement, surveying, sanitary
items, calculating amount of rainfall, traps, fluid properties,
Information about rocks and soils, concept of raft footing etc., are
given.
This book was written by referring many other civil engineering
books and based on my practical experience.
I express special thanks to my parents and my friends for their
encouragement.
I hope that, this book will prove immensely useful for civil
engineering students.
I have done personally some experiments, which you can also do,
as they were all simple experiments; to understand clearly and
easily.
I have started writing this book during my B. Tech final year, and
completed after my end exams. I’ve utilized COVID19 lock down
days for completing faster.
Dedicated to my Lecturers
Contents
Page No.
1. Properties of
fluid.
4 - 10
2. What is sewage, sullage, refuse,
garbage.
11
3. Brief information on different Types of pipes
12 - 15
4. Latches - Fixtures and fastenings for doors and
windows.
16 - 17
5. Calculation of rainfall capacity.
19
18 -
6. Waste water trap and its uses.
20
7. Behaviour of water at high temperatures.
21
8. Open sewers - problems and remedies.
22 - 28
9. Tests on concrete at site.
31
29 -
a) Slump cone test – workability.
b) Compressive strength test.
10. plumbing connections layout.
- 34
32
a) Water supply.
b) Sanitary connections.
11. Floor area ratio (F.A.R).
35
12. What is shear force, shear stress, moment and equilibrium.
36 - 41
13. What are street gutter, Inlet, catch basins, man holes.
42 - 43
14. What is orifice, mouthpiece, weir and notch.
44 - 45
15. Tests conducted on bricks.
46
16. Brief information on Tiles &
Pottery.
47 - 49
17. Water treatment
plant.
50 - 54
(purification of water detail process)
18. Hydration of cement in
detail.
55
19. Steps involved in concreting.
56 - 58
20. Water in civil engineering.
59
21. Brief information on rocks.
60 - 61
22. Detail about soil – its origin and types.
62 - 63
23. Wood - In construction
64
24. Estimation of R.C.C beam quantity & cost of material.
25. Paints
65 - 67
68
a) Enamel paints.
b) Emulsion paints.
c) Varnish.
26. Surveying and its importance.
69
27. How to calculate area of a plot.
70 - 71
28. Demolishing.
72
29. Centroid and centre of gravity.
73
30. Detail process of building construction.
74 - 75
31. Mechanical properties of
materials.
76 - 78
32. Types of road pavements.
79
a) Flexible pavement.
b) Rigid pavement.
33. Information about railway & Component parts of railway
track
80 - 82
34. Causeway.
83
35. What is estimation and specifications.
84
36. Tender, contract, Quotation, tender form & tender notice. 85
37. Precipitation & forms – Rainfall types
86 - 87
38. Concept of raft footing.
88 - 89
39. Staircase
90 - 93
a) Types of stairs.
b) Terms used in stair case.
40. What is lintel and sunshade.
94
41. Valves and their importance.
95
42. Contours and uses.
96
43. Plasticity and elasticity.
97 - 98
44. P-T slab.
100
99 -
45. Rain gauge.
102
101 -
46. Catchment area & runoff.
103
47. What is irrigation.
105
104 -
48. 3D Home plan design by dream plan software.
106 - 107
49. Detail about causes of cracks, preventive measures and repairing
methods.
108 - 113
?
114 - 115
INTRODUCTION
Civil engineering is the vital subject in engineering.
In my words, it is a king of engineering.
Here I’m telling the importance of civil engineering – a kingdom without a
king, how it can be ruled? So, without civil engineering everything is not in
a proper manner.
World without civil engineering –
1) Without shelter how can we live.
2) How can we cross a river or a valley without a bridge.
3) Transportation is not possible without roads.
4) How can we control floods without dams and reservoirs.
5) Improper drainage system without civil engineering.
Civil engineering consists of many fields such as
a) Structural engineering: It deals with the design and analysis of
structural members.
b) Architectural engineering: Deals with the planning, designing
exterior & interior of building. It mainly focuses on appearance of
structure.
c) Environmental engineering: It deals with water supply and sanitary
engineering.
d) Rehabilitation engineering: It deals with the repairing of damaged
structures which includes restoration and renovation.
e) Transportation engineering: It deals with highways, railways, water
ways, airways. The movement of men and material from one place to
another place.
f) Irrigation engineering: It deals with the artificial supply of water to
agricultural fields like construction of dams, reservoirs, canals etc.
g) Geotechnical engineering: It deals with the soil and its properties. In
civil engineering before construction of a structure it is essential to
know the type of soil & rock, on which foundation the structure can
rest safely, like constructing sky scrapers, dams. The investigation is
carried in foundation rocks by geologist.
h) Forensic engineering: It deals with investigation of failures i.e.
finding causes of failure by collecting data related to materials and
products used in construction & conducting experiments for evidence
in submitting to courts.
CIVIL ENGINEER
Civil engineer is the only man who spent is life time for the
development of nation.
Aesthetic appearance of city depends on a civil engineer.
CIVIL ENGINEER = “GOD in real life”
CIVIL ENGINEER = FOR THE PEOPLE
A man who work for the people to ensure safety of living for them.
Construction of buildings to provide shelter for the people.
Construction of roads and railway tracks to provide
transportation facilities for the people.
Construction of a bridge to cross a valley or a river for the
people.
Construction of dams and reservoirs to provide irrigation
facilities for the people.
Constructing water treatment plants for safe water drinking,
in the health point of view for the people.
Construction of sewers to convey sewage of the people.
Repairing of damaged structures using different techniques
for the people.
Proper drainage system; to prevent waste water stagnating on
roads by which breeding of mosquitoes causing diseases for
the people is minimized.
1. PROPERTIES OF FLUID
Fluid: A fluid is a substance which has capability of flowing, that deforms
on application of shear stress.
Example: water and air. (If there is a pipe of 20 cm diameter in which a
water or any gas is carried to a desired location, here the pipe diameter after
going certain distance is changed to 10 cm, what does it results? Nothing,
the water flows through this pipe also without any problem, because they
can flow in any shape by deforming)
What about solids; they cannot flow and not change their shape easily.
All liquids and gases are fluids.
VISCOSITY
The property of a fluid which offers resistance to the movement of one
layer of fluid over its adjacent layer. It is the internal frictional forces which
arises between adjacent layers of fluid in motion.
Adjacent means next layers
It is the measure of resistance to deformation.
Viscous: Having sticky consistency.
Example: Oil have more viscosity than water, that
you can observe by pouring water and oil on a surface.
SURFACE TENSION
It is the property of a liquid surface that resist an external force. It is
expressed in N/m.
Before knowing about surface tension, you have to know about the
adhesion and cohesion.
Adhesion: It is the property of liquid which sticks to another surface.
Examples:
1) Water having more adhesion which you
can observe by conducting a simple experiment i.e., Take one of your finger
and dip in water, then take out your finger and come close it to your other
hand finger, then you can notice the attraction like a magnet by water
molecule and cling to your finger surface, which is called adhesion.
Without adhesion, water don’t lie between your fingers & won’t stick, it just
falls down.
Cohesion: It is the attraction between molecules of liquid, which sticks
together and form a whole.
Water is a molecule, but when you add it to other water molecule it
becomes whole.
Examples:
1) Without cohesion, water in a beaker appears in the form of rain in flight;
like droplets.
2) You can clearly observe cohesion also by the finger test with a droplet,
just like first example of adhesion experiment given above. This time, dip
both fingers in water (molecules attach to both fingers), then Make fingers
come closer to each other. It attaches and form whole one.
slowly separate your fingers from each other, you can also observe the
cohesion between particles making the whole droplet like an elastic
material.
Cohesion between water molecules; it’s a bond.
Surface tension: Surface tension occurs due to the cohesive forces between
molecules of the liquid. The cohesive forces pull inward and behave like a
whole one which resist an external force.
It is just like an entry door or gate of building, how strong it is, just like
a shield it creates to resist the external force.
1)
Here, I have taken one piece of ‘Toor dal’ (one type of pulses; food
material; which is solid not hollow.) and dropped from a height simply, the
toor dal piece was sank to the bottom of the glass.
2)
Here, I have slowly placed the one piece of Toor dal on water, wow! Its
floating without sinking. This is due to the resistance of liquid surface to
external force, which is surface tension; due to cohesion between
molecules.
Actually, Toor dal is heavier than water, but why this time it doesn’t sink,
this is due to surface tension.
1) Placed
slowly
simply
2) Dropped
1) In the above picture, I placed a steel sheet on water slowly & gently,
without applying much force, it floated. Actually, steel having more density
than water, but here why it doesn’t sink, this is happened due to surface
tension, which only resist certain capable force, if force exceeds than its
resistance, it results the second one. (Note: steel sheet should be dry while
placing)
2) If you simply drop the steel sheet, it breaks the cohesion between
molecules and leads sinking to the bottom.
Newtonian Fluid & Non-Newtonian Fluid
Newtonian fluid: The fluid which do not change its viscosity on the
application of Shear force. A constant viscosity and linear relationship
between shear stress and shear rate. Ex: Oil, Water, alcohol etc.
It only changes its viscosity on temperature and pressure.
For example: Viscosity of oil decreases on high temperature.
Non-Newtonian fluid: The fluid which changes its viscosity on application
of shear force. It doesn’t follow newton law of viscosity.
Types:
1) Dilatant: The fluid viscosity increases on application of shear force. It
doesn’t depend on time of application of force.
Examples: Quicksand; when someone stuck in this, if they apply much
force to come out, it results in increasing viscosity of fluid and they won’t
come out.
Cornflour & water mix: After mixing water in corn
flour, if you simply leave this fluid from you palms, it flows, but if you
apply some force on the fluid, it behaves like a solid material and increases
more viscosity instantly.
2) Pseudoplastic: The fluid decreases its viscosity on application of shear
force.
Example: Tomato ketchup; shaking this bottle cause decrease in viscosity
of sauce, then it comes out easily, but rapidly.
3) Rheopectic: The fluid increases its viscosity on application of shear
force, but depends on duration of force application. If longer time of force,
then more increase in viscosity.
Examples: Lubricants, gypsum paste etc.
4) Thixotropic: The fluid decreases its viscosity on application of shear
force, it also depends on duration of application of force.
Examples: Glue, gel.
DENSITY & RELATIVE DENSITY
Mass density: It is the ratio of mass of substance to that of its volume.
Density = Mass/volume
Weight density: It is the ratio of weight of substance to its volume. Here,
acceleration due to gravity (g) is considered.
Relative density: It is the ratio of density of a substance to density of water.
It is also called specific gravity. It has no units.
CLEAR YOUR QUERIES
2. WHAT IS SEWAGE – SULLAGE &
REFUSE - GARBAGE
Sewage: The Semi-solid, fluid waste discharge from water closets, urinals,
bath, kitchen sinks, wash basin, industrial & storm water is called sewage.
Sewage is of two types
1. Fresh sewage: It indicates that sewage which has recently produced.
Colour is grey.
2. Septic sewage: It indicates that some time was passed after sewage
produced. It is dark brown or black colour.
Sanitary Sewage: It indicates the semi solid, fluid waste from toilets, bath,
sinks from residential, industrial, institutional buildings etc. but not storm
water is called sanitary sewage. It is also called Dry weather flow.
Sullage: It includes the liquid waste from bathrooms, sinks. It is also a
waste water, but which does not create bad smell.
Refuse: It includes all types of dry wastes from community such as plastic,
ash, paper.
Garbage: It includes Refuse & decayed fruits, vegetables etc. It is semi
solid.
3. TYPES OF PIPES
Different types of pipes based on material for various uses, they are:
1) Cast Iron Pipe: These pipes are used in
water supply & sewage systems.
These pipes are durable, & have high strength.
These pipes diameter varies from 5cm to 120cm and length 12 to 20
feet.
These are made by pig iron which means iron having high carbon
content.
It is brittle & cause corrosion inside the pipe so, bituminous coating
is applied for preventing corrosion.
2) Galvanized iron pipe: These pipes are used for carrying water supply &
gas
These pipes are having diameter 0.5 inch to 6
inches
generally.
The mild steel sheet is dipped in zinc solution
for preventing
corrosion. This process is called galvanization.
3) Wrought iron pipe: These pipes are having low carbon content.
It is malleable & ductile.
It is made by forging the metal with hammer or
other tools by blacksmith.
4) Plastic pipes: These pipes are made by poly vinyl chloride (PVC). These
pipes are used for water distribution.
PVC Pipes:
These pipes are suitable for normal, acidic & alkaline water but not
suitable for hot water supply. Used for electrical wire installations
also.
These pipes are light in weight & resistance to bacteria, fungus and
corrosion.
Length up to 20 feet and diameter varies from 1 inch to 12 inches.
CPVC Pipes:
CPVC means chlorinated PVC, having higher chlorine content.
It can with stand to high temperatures.
These pipes can convey both hot and cold water.
It has greatest insulation than copper pipes.
Can resist temperature up to 200°F.
UPVC Pipes:
Un Plasticized PVC made with more rigid material.
It is used for conveying waste water.
In this plasticizer is not used.
NOTE: plasticizer is used for making more flexible.
HDPE Pipes:
High Density Poly Ethylene Pipes are manufactured by polymers and
ethylene, it is a thermo plastic but can become thermosetting by cross
link poly ethylene.
It is flexible and have high tensile
strength.
It is used for high pressure water conveying system like pipes using
in bore wells with pumping motors.
Density varies between 930 to 970 kg/m3.
It is strong and durable.
5) Asbestos cement pipes: These pipes are made by asbestos & cement
compressed by rollers.
These pipes are not subjected to corrosion.
Suitable for carrying sewage but not
drinking water.
Asbestos is banned in some
countries because it causes diseases.
6) Copper pipes: These pipes are used for carrying hot water.
It will not bend when subjected to high temperature.
It is durable and resistance to corrosion.
Drawback is less heat insulation
(when you touch this pipe during hot water supply, you may guess the
result now).
7) Prestressed concrete pipes: These pipes are made by inducing internal
stress in concrete by tensioned steel to counter the stresses caused in pipe
during flow. For sewage, industrial, domestic needs it is used.
These pipes are having large diameter and good resistance.
It can withstand to high stresses.
8) Glass reinforced plastic pipes:
These pipes are manufactured using glass fibres, polymer and fillers.
It is resistance to corrosion and UV rays.
It is durable and light weight.
It is used in industrial waste water convey and other power plants and
oil industries.
9) Stone ware pipes: These pipes are made by clay which is fired at high
temperature at 1100°C to 1300°C
It is impermeable and resistance to scratch.
It looks like C.I pipes, but stone ware is made of clay, and having short
length than C.I pipes.
Used for house soil waste carrying to street sewer.
4. LATCHES - FIXTURES AND
FASTENINGS FOR DOORS &
WINDOWS
Latch: It is a type of mechanical fastener used to join two surfaces for their
regular separation.
It is permanently fixed to a surface and used for temporary
connection with another surface.
It is used as a secure for protecting materials inside building from
thieves.
It provides privacy to rooms.
Different types of fixtures & fastenings are:
1) Aldrop bolt: It is a latch fixed in exterior face of door, where pad lock is
to be provided.
It is called sliding bolt.
2) Tower bolt: It is fixed at backside of door for internal privacy.
3) Hinges: These are fixed to frame and
shutters of door with screws. It is used for freely rotating the door about its
axis.
It is a type of joint having free movement at it.
4) Hasp & Staple: These are fixed to small doors, windows and other
olden things storing boxes to provide pad lock.
5) Pad lock: It is used for securing the room or any other things.
It is provided to aldrop bolt for security.
It is having keys for opening and closing.
6) Mortise Lock: It is a type of lock provided at edge of door for secure.
Having connection with door frame and shutter.
It is directly fixed to the door
It is used for office doors and other doors.
5. CALCULATION OF RAINFALL
CAPACITY
Example:
Shower and bucket method
consider a bucket of diameter 0.25m and height 0.27m.
volume of bucket =
x 0.252 x 0.27
(1m3 = 1000 lit)
= 0.0133 m3 = 13.3 litres.
The bucket is kept under a shower and shower is on, time is noted using
stop watch.
The time taken to fill the bucket is 1.40 minutes = 100seconds.
13.3 litres of water filled in 1.4 minutes.
So, for 1 minute =
9.5 litres/minute.
Total discharge = 1.58x10-4 m3/s.
Rainfall capacity calculation:
Considering the area of 1000 sq. km.
Monsoon rainfall with continuously for about 24 hours
So, first calculate depth of rainfall for 1 square. metre area.
Keep the container having dimensions 1mx1mx1m in rainfall and note
down the depth of water filled in it for 1 hour. (it should be in open
place free from obstructions).
By the test, the depth of water filled is 20mm, when I tested.
For 1sq.m area intensity of rainfall is 20mm/hour.
Volume of water for 1 m2 area for 1 hour is 1 x 1 x 0.02 = 0.2m3 = 0.02 x
1000 =20 litres.
For 1 sq.km (or) 1000000 sq. meters = 20x1000000 = 20000000
litres.
For area of 1000 sq.km the volume of rainfall for 1 hour is
= 1000x20000000 = 20x1010 litres. = 200 BL (Billion
litres)
For 24 hours (1day) = 200x109 x24 = 4800 BL.
So, Total rainfall capacity is 4800 billion litres for 1000 sq.km area about
24 hours.
Some losses may occur due to infiltration and evaporation & absorption by
vegetation. We can consider 25% losses.
Here, I have used a container for measuring rainfall, but for accuracy, the
rain gauge instrument is used to know depth of rainfall.
6. WASTE WATER TRAP
Trap: It is a device used to collect the waste water from kitchens,
bathrooms, rain water from roof and water from rooms (when cleaned the
room with water), and conveys it through a pipe to soil pipe.
This trap collects only sullage.
It is provided with top gratings which are made of stainless steel,
galvanised iron or plastic one.
Gratings are provided to prevent entry of large size solid particles
which causes blockage.
Sufficient water seal is provided in order to prevent entry of foul
gases in to the rooms of house.
NOTE: Its intention is to catch the waste water (sullage) from all rooms &
to convey it through soil pipe; to prevent foul smell entering house,
sufficient water seal is maintained and blockage due to large size particles is
prevented by mesh like cover at top.
7. BEHAVIOUR OF WATER AT HIGH
TEMPERATURES
Water is the one which provides multiple uses to human beings.
At 4 ℃ density of water is 1000kg/m3.
Upon heating of Water, the molecules will move and separate from
each other which results in expansion. The volume of water will be
increased, then density of water decreases.
i.e., If mass of a water is 1000 g having volume 1000 ml it may increases to
1030 ml by heating of water so density of water is
=
= 0.97 g/ml
= 970 kg/m3
On heating the water, the cohesion between the particles decreases and
volume increases.
Upon heating, the bond between hydrogen and oxygen atoms will
decreases and they are stretched, so water volume increases.
Actually, the hydrogen and oxygen are a gaseous material when the
bond breaks between these two, due to high temperature, then the
gaseous material try to move up with certain pressure; So, water level
also rises and volume increases which in turn results in decreasing of
density.
NOTE: You may have a doubt; why they are in motion due to heat? = 1)
Imagine if you were in a closed room, the temperature in the room is very
high. At this time what you’ll do? you want to come out of the room and
take deep breath then relax.
Density = mass/ volume.
8. OPEN SEWERS - PROBLEMS AND
REMEDIES
Sewer: It is an underground conduit or a drain to carry waste water.
Open sewer: The channel for carrying waste water which is open at top to
atmosphere is called
open sewer.
Present situation in some places
The present situation in some areas during a heavy rainfall is stagnation of
waste water on roads.
Some of the photographs collected from a city are shown below
More than half of Bike tire is submerged in waste water
The photographs are taken at my nearby locality
In this photograph a mark indication is given to know it is an open
sewer beside the road which is completely Submerged not appearing
to us.
If a stranger enters this place, he/she don’t know there is an open
sewer at that place if there is an urgency they keep moving in the flow
and they may fall in that sewer and cause severe injury or even leads
to death.
This is really a dangerous situation.
Flooding of entire area with waste water.
In some areas the dividers are submerging in waste water.
The situation is really panic while driving a vehicle in that.
Situation of Sewers and problems with them.
In some countries there are open sewers and open drains. As it is
open, the people are throwing all the different types of wastes like
plastic waste, medical waste, e-waste & construction waste in that, it
causes blockage of flow in the sewers or rate of flow is slow down.
At the time of heavy rainfall, the rain water enters the open sewers
and drains, but due to the clogging of sewer by all types of wastes, the
rain water which is mixed with sewage are returning to roads and
stagnating on roads. (reversing of flow)
This causes nuisance to the road users.
Causes of blockage:
Blockage due to throwing of all different types of wastes in that.
Blockage due to weed growth of plants
Due to open, In the presence of sunlight the plants will grow in that
and causes blockage of flow.
Effects
1. It results in unhygienic conditions prevail in the city & leads to
diseases.
2. Unaesthetic appearance of city, it looks very dirty.
3. Breeding of mosquitoes and causing diseases like malaria, dengue etc.
4. The situation is really panic while driving a vehicle in that stagnated
water on roads.
5. We cannot collect all plastic waste, medical waste, e-wastes. Because
they are left in open sewers and drains.
6. There is nuisance of foul smell due to open sewers.
7. It interrupts our work when we are even using cars and other like that
vehicles as they cannot move in stagnated water.
8. Discomfort to the road users.
9. In case of emergency for ambulance or any other it is not possible to
move as the waste water stagnated there.
Remedies:
First, removing waste from sewers and closing the open sewers with
top coverings using RCC slab.
At the kerb providing gratings of width 150mm and height 100mm.
Providing small man holes
on coverings for removing any sand or any soil particles present in
sewer with size 600x600mm.
Gratings
kerb
kerb is a raised one at the edge of road
This is the grating which is inlet to rain water flow in sewer.
Providing like this covering using RCC, then no one will throw any type of
waste in that sewer.
Results
By this people can’t throw anything in sewers because it is not open.
No stagnation of waste water on roads.
We can use the road during heavy rainfall also.
The flow will be easier in sewers and there will be no difficulty in
movement.
The load on treatment plant is also decreased.
As it is not open without sunlight the photosynthesis process does not
undergo, so plants will not be grown in sewer and no blockage.
The waste liquid can’t come outside and no foul smell.
If the blockage occurs at gratings we can remove easily and we can
walk in rain water because it is not mixed with sewage water.
Improves aesthetic appearance of city.
All the wastes can be recycled & re-used.
Say good bye to water borne diseases.
We can collect all different types of wastes 100% and it can be
recycled& reused.
“BETTER
SEWERS BETTER HEALTH”
9. TESTS ON CONCRETE AT SITE
The important tests on concrete at site during construction of a building are:
1) Slump cone test.
2) Compressive strength test.
Slump cone test (Workability):
This test is carried out to find the workability of concrete.
Workability: The property of fresh concrete without any difficulty or effort
the concrete shall be can be mixed, transported, placed, compacted and
finished without losing its homogeneity is called workability.
Workability of concrete = No difficulty and No loss
of homogeneity during the above operations.
The test is performed by mould having dimensions 10 cm diameter at
top, 20 cm diameter at bottom and 30 cm height.
16 mm diameter tamping rod used.
Procedure:
First, the freshly mixed concrete is poured in the mould in three
layers each layer is compacted by tamping rod with 25 strokes per
layer.
Level the surface properly using trowel.
Then raise the mould in vertical position and check the difference of
height between mould and specimen, using measuring scale.
The difference is the slump value.
Take the slump value in millimetres.
There are four types of slumps they are: true slump, zero slump, shear and
collapse.
Slump means sudden fall.
1) True slump is the correct one which is to be taken for building
construction works.
2) Zero slump is the one which has no workability due to low water
cement ratio. It is used in road construction.
3) Collapse slump is due to more water content but it is not used because
concrete loses its homogeneity due to excess amount of water in mix.
It is used for lean concrete mixes.
4) Shear slump is inappropriate, the test has to be reconducted
Workability
Slump in mm
Very low
0 - 25
Low
25 - 50
Medium
50 - 75
High
75 - 100
Very high
100 - 150
Compressive strength test:
This is the important test, which is used to know the crushing strength of
concrete in order to know it’s bearing value.
In this test, concrete cubes are prepared by size of 15cm x 15cmx 15
cm.
The cubes are immersed in water for 28 days for curing.
Test is conducted by placing the cube in testing machine.
The load is applied gradually at a rate of 140 kg/cm2 per minute until
specimen fails.
Compressive strength = load/area of specimen
Actually, the cubes are tested after curing for 7 days, 14 days, 21 days and
28 days.
After 28 days it attains almost 100% strength.
10. PLUMBING CONNECTIONS
LAYOUT
SANITARY CONNECTIONS LAYOUT
Dotted line in the sanitary connections indicates, the pipe is below the
ground.
Ventilating pipe is provided to escape of air freely, in order to avoid
blockage of flow.
Plumbing means it is a system of pipes, fittings and tanks for water supply
and sanitation.
Water supply and sanitary connections are to serve human basic needs i.e.; to
carry water from overhead tank to different points like taps, shower through
water distribution pipes for various uses like drinking, washing, bath and
toilets. Human excreta are carried through soil pipe to street sewer for
disposal.
V.P = Ventilating pipe.
I.C = Inspection chamber.
W.P = Waste pipe.
N.T = Nahani trap.
W.C = Water closet.
O.H.T = Overhead tank.
11. FLOOR AREA RATIO
Zoning ordinance
In the year 1916, zoning resolution was passed in New York city (United
states) citywide zoning code; to prevent tall massive buildings obstruction of
light & air for reaching the streets below.
In the year 1961, Revision to zoning ordinance introduced F.A.R (FLOOR
AREA RATIO).
Floor area ratio
Purpose:
To control height and size of the buildings.
For quick evacuation, in an emergency during a disaster.
To limit urban density.
To limit number of people.
To make availability of open space infront or back of building.
It is the ratio of total covered area on all floors to plot area.
Here, If the maximum FAR is 1.0, then if the plot is covered 100% with 1
storey, is equal to plot covered 50% with 2 storeys, is equal to plot covered
25% with 4 storeys.
NOTE: Byelaws which include FAR, setbacks, height, size etc., are
considered for ensuring safety from natural calamities and facilitate good
and proper ventilation for free light and air circulation in every building.
For example: If you were got stuck in a 5th storey of a building in a room
with fire calamity; having a door (which is with full of fire which you cannot
open). Here question is Without byelaws (having all buildings constructed
with no spaces between each other, imagine it!) how can you get rid of from
that dangerous situation? What is the use of windows? Even though
windows are there, how can you get off from that, as other building wall is
just beside it.
12. SHEAR FORCE, STRESS, MOMENT
& EQUILIBRIUM
Shear force: It is the unaligned force, which means, the force causes one
side of body to push in one direction and other side of body in opposite
direction.
For example, when point load act at free end of cantilever beam, it results in
the point at which load acted is rotated in one direction, and other end
(Fixed) is turned in another direction.
By a Practical example you can conduct a simple experiment; which is the
following one:
Take a broom stick or steel scale and hold it vertically with your hand
at centre of broom stick or scale (Hold simply without much force).
Apply the force horizontally at top side by another hand.
You’ll notice, the top side of stick turn in one direction and bottom
part will turn in opposite direction.
Normal
Force applied at top
In beams, the shear force is the force which is perpendicular to the
longitudinal section and parallel to the cross section.
Stress: It is the measure of load applied on a body per unit area. It is
expressed in N/m2.
Stress = Load/area
It also used for measuring the resistance of material.
Shear stress is the shear force per unit area.
Shear force is the force, which
results in breaking of element on which it acts. It is the reason for the cause
of rotation of beam when subjected to it.
Pic
1.
Pic 2.
To understand the shear force’s impact when acted on a member, I’m
showing an example with broom stick.
Consider broomstick as a beam and fixed at one end. Look pic 1.
Here, one end is completely fixed and load is applied at free end, then
rotation is happened at free end in clockwise direction, and also at fixed
end same clock wise rotation is happened, which you cannot see, as it was
fixed.
To make you clear, what is happened exactly at fixed end due to the
moment produced, I’m showing another picture (Pic 3.) See the rotation
between my fingers, this is exactly happened in pic 2, but we cannot see.
Pic 3.
But due to fixed support, the rotation created is resisted by it.
If the moment exceeds the resistance of fixed end, then element (broom
stick) will lift up in fixed end. No crack resulted, only separation between
element and fixed end.
If the resistance of fixed end is quite more than moment, then it opposes
the rotation induced at fixed end. But, if element is weaker material, then
due to force applied at free end, it causes breaking of element near the
fixed end (see pic 4).
Pic 4.
If the material is flexible, only bending happens, but if material is rigid it
results in breakage on application of heavier loads.
Shear force makes one end of body to move in one direction and other
side in opposite direction, so two forces are acting one opposite to
another, but not in exactly opposite to each other.
When both ends are fixed, the load applied at centre is distributed either
right or left. It results in rotation clock wise or anticlockwise.
Why the force moves either right or left?
I have taken a paper and fixedly supported at both ends and applied load
with my hand at centre.
It resulted pic 6.
Pic 5.
Pic 6. (teared at edge)
Oh! It resulted in tearing of paper at one of the fixed ends, but why not at
centre? This is due to the application of force. The force does not act at
centre exactly, it moved to one supported end and stopped due to fixed end,
but the resistance of fixed end is greater than the moment, so the failure
occurred near the support. That is why we consider shear force as an
unbalanced vertical force, which moves either left or right of the section.
Another one by sharp scale.
Pic 7.
Here, I have applied the load with sharp steel scale, exactly at centre, which
resulted in pic 7.
What happened here, why it has cut exactly at centre, because the force
is acted at single point and sharply. Load is distributed to two sides, not
only one side. The material opposed the force which I have applied, but
due to poor resistance at the centre, it was teared exactly at centre.
From the below diagram, you can understand, the force acted at centre is
distributed to both sides equally. The force is resisted by fixed ends and also
returned the force to same place where it has come from. (Newton’s third
law of motion). The bend portion is the shear zone. The force reversed to
this zone. Result is breaking.
RF = reversed force, DF = distributed force.
Diagram
So, generally in maximum cases, the sudden impact load is not distributed
properly, so we consider load either right or left. Shear force acts
maximum at supports, that is why we provide maximum stirrups near
the supports and minimum at centre.
Shear force example: when you cut paper with
scissor, here due to shear force, material will tear.
When you apply force for cutting paper with scissor, the first force act
downwards and second force act upwards which is not quite opposite to
another force, it is having some distance between each. The two unlike
parallel forces act on paper which resulted in shear force at centre.
Strain: It is the measure of rate of deformation of body due to stress. It is
the ratio of change in dimension to original dimension.
Compressive force: The force which cause shortening of body. It is pushing
force.
Tensile force: The force which cause elongation of body. It is pulling force.
Concrete is weak in tension, but steel in strong in tension.
Moment: It is the force which cause rotation of a body.
Bending moment is reaction induced in structural element when force or
moment is applied, which causes element to bend. The structural elements
which undergo bending moment are beams.
Bending depends on the type of material body and type of ends; fixed or
hinged.
Bending moment is the product of force and perpendicular distance.
Measured in N-m.
Equilibrium: A body is said to be in equilibrium, if opposing forces acting
on the body are balanced.
Civil engineer’s intension is to make the structure to serve safely for the
occupants without collapse. So, the engineer makes it possible by calculating
bending moment and shear force values for knowing, how much the
structural elements should resist the loads acting on them.
Finding the yield strength of steel, for knowing its resistance to the force.
Yield strength means, the load at which material undergoes plastic
deformation.
Finally, maintaining equilibrium for balancing the loads, and to distribute
loads properly.
13. STREET GUTTER, CATCH BASINS,
MANHOLES
Street gutter: It is a small narrow drain located parallel to the road for
carrying the waste water from streets, and it is connected to inlet of a catch
basin.
Rain water from rooftops of building collected and
carried to street gutters.
Inlet: It is an opening for the entry of rain water from gutters and streets to
catch basin.
Catch basin: It is a chamber for collecting the waste water from inlet, for
catching the debris, silt and sand particles, which will settle down and can
be removed easily to avoid clogging of flow in the sewer.
It is connected to the sewer for conveying the waste
water in to it.
Catch basin
Manhole: It is a structure which provide access beneath to the sewer, for
inspection and maintenance of sewers in case of blockages.
Having top cover over it.
14. WHAT IS ORIFICE, MOUTHPIECE,
NOTCH AND WEIR
Orifice: It is an opening made in the tank containing liquid for measuring
the rate of flow (Discharge) of liquid.
Mouthpiece: It is a short length of pipe fitted to orifice to measure rate of
flow of liquid through pipes.
Its length is not more than 2-3 times the its diameter.
Notch: It is an opening for a channel just below the top edge, used for
measuring rate of flow of liquid through channels and tanks.
It is generally made with steel plates, and also used in weirs for
calculating rate of flow.
Weir: It is a barrier used to control the flow of water in rivers and other
water bodies.
It raises the water level on upstream side and diverts to downstream
side.
It is also used to measure discharge.
To prevent flooding.
Rate of flow can be calculated by a formula i.e., Q = CLHn
C = flow coefficient for structure.
L = width of the crest
H = height of water over crest (Highest level that river reaches certain
times).
n = 3/2 for horizontal weir and 5/2 for v-notch weir.
NOTE:
Every hydraulic structure is constructed to control the water flow and
prevent flooding & also erosion.
15. DIFFERENT TESTS ON BRICKS
Before using in the construction, the bricks are tested for the quality –
For good standardized construction.
To ensure safety for the inhabitants.
Types of tests for red clay bricks:
1) Soundness test: A good brick
should give metallic ringing sound when hit with another brick.
2) Drop test: A good brick should not break when dropped from a height of
1 meter.
3) Water absorption test: A good brick should not absorb more than 20%
of water.
4) Compressive strength test: A good brick should have enough
compressive strength of
minimum 105 kg/cm2.
5) Efflorescence test: A good brick should not contain more salts which
cause white patches on
surface of brick when immersed in water for 24
hours.
6) Hardness test: A good brick should not have any impression left on it,
when scratched with
finger.
7) Structural shape: Should have uniform rectangular block shape without
irregular shape.
8) Fire test: A good brick should resist temperature up to 1220 °C
16. BRIEF INFORMATION ON TILES &
POTTERY
Tile: It is a structural component made of clay and some minerals, by
making to desired shape and heating up to suitable temperature. It is used to
cover roof, walls and floors.
Uses:
To make the roof protect from heat sun, rain etc.
For better aesthetic appearance.
To remove the fluids if any, when fall on the surface very easily with
a little effort.
To protect wall and floor by non-penetration of water through it by
vitrified tiles.
To clean quickly and easily.
Before knowing about tile, we have to know about the ceramics.
Ceramic: The word ‘ceramic’ is a Greek word which means pottery and tile.
Ceramics are of following types: Earthenware: It is a type of pottery in which the clay is heated below 1200
°C generally for making unglazed pottery.
Composition: Kaolin (25%), ball clay (25%), quartz (35%), feldspar (15%).
Stoneware: It is heated more than earthenware to a high temperature (up to
1300 °C) to make vitreous and semi vitreous materials.
It has developed after the earthenware.
Its composition is fire clay, ball clays,
quartz, feldspar and Grog.
Ball clays are kaolinitic sedimentary clays.
Porcelain: It is heated up to 1400 °C, more than stone ware. It was first
invented in china.
It is having better strength, toughness, non-porous and translucence.
Composition: Kaolinite, feldspar, ballclay, bone ash, glass, alabaster,
petuntse.
All these; bone ash, soap stone, alabaster, petuntse are of white colour,
therefore porcelain made are of generally in white colour.
Bone ash: It is the white material made by calcination of bones.
Ceramic tiles: These tiles are used to cover floors and walls.
Porcelain also come under this category having less than 0.5% water
absorption.
Only difference between ceramic tiles and vitrified tiles is, vitrified tiles are
glossy.
Vitrified tiles: These tiles are of low porosity, which are glossy in nature.
These are made by hydraulic pressing of clay, feldspar, silica and
quartz which results in vitreous surface.
NOTE: Improper joints between tiles on floor leads to many complications
such as dampness by water penetration. So, proper care should be taken
during laying of tiles.
17. Water treatment plant
Purification of surface water: The process of treating the surface water
for effective removal of suspended, colloidal, dissolved particles & diseasecausing organisms like bacteria for safety to consumers.
It involves
1) Plain sedimentation
2) Screening.
3) Pre chlorination
4) Aeration
5) Sedimentation with coagulation
6) Filtration
7) Post chlorination
8) Storing in sump
9) Pumping to overhead tank
10)
Distribution.
Plain sedimentation: The process of settling down the suspended particles
under gravity is called plain sedimentation.
This process is naturally happened at raw water source such as lakes
and storage reservoirs.
The particles having greater density will settle first.
The plain sedimentation process, which is completed at the raw water
source.
Screening: The process of removing the larger size particles such as leaves
and other floating
particles by providing mesh like materials, which are
called screens.
Next the raw water enters the treatment plant through pipes & pass through
some stages for complete treatment. These are the following stages in
purification of water at treatment plant.
Stilling chamber & Venturi flume:
First good water(treated) mixed with chlorine gas and activated carbon,
then it conveyed in to this chamber with small diameter pipes. Raw water
first enters this chamber with large diameter pipe.
Stilling chamber
chlorine gas cylinder
Mixing chamber: In this chamber, the
alum is mixed well with raw water for coagulation process.
Aeration: In treatment plants water is
passed through a series of concrete steps to remove odour of water. This
process is called aeration.
Sedimentation and Coagulation:
Sedimentation means settling down the particles.
By the addition of coagulant like alum the suspended particles become floc
& settle down due to heavy density. Floc means clumped mass of particles.
In this stage, the suspended particles are removed.
In the sedimentation tank, clarifier & flocculator are there.
Flocculator is inner one having diameter 10m serves as a
flocculation basin for settling heavy size particles.
Clarifier is outer one which is having diameter 25m. After
flocculation, the water enters this chamber and remaining
suspended particles settles down.
Filtration:
The process of passing the water through sand and other granular materials
for the removal of residual-suspended and colloidal particles.
In this stage colour, odour and taste are removed.
Bacteria is also removed.
Filter media consists of
layers they are:
1) Gravel pebbles = 37-50mm.dia.
2) Gravel = 12-37mm.
3) Gravel = 8-12mm.
4) Gravel = 3-8mm.
5) Grit = 2.3-3mm.
6) Sand = 0.45-0.7mm.
Inside filter bed (Filter media)
Filtration is done by
Post chlorination:
This is the final stage in treatment process, in this stage the chlorine is
added about 0.2 – 0.5 ppm. For killing of diseases causing microorganisms.
Then storing in sump and pumping to overhead tank for distribution.
OVER HEAD TANK
18. HYDRATION OF CEMENT
Hydration: Absorption of water.
The process of adding water to cement, which results in a chemical reaction
between these two and finally the cement hardens like rock.
How it hardens?
For the manufacturing of cement, materials like lime, silica, alumina etc.,
are required. These raw materials are subjected to high temperature during
manufacturing process, then these are formed to compounds, called as
Bougue compounds.
Bougue compounds are: 1) Tricalcium silicate
2) Dicalcium silicate
3) Tricalcium aluminate
4) Tetra calcium aluminoferrite
When water is added to dry cement, a chemical reaction starts between
these two, and heat will be liberated from the cement and it absorbs water
for hardening.
Tricalcium silicate is responsible for early strength development and its
reaction with water gives rise to the following equation.
Tricalcium silicate + water
hydrate + Calcium hydroxide + heat
Calcium silicate
Dicalcium silicate is responsible for later strength which takes a long
time.
Tricalcium aluminates react with gypsum and water; which gives rise to
ettringite (forming crystals) + heat liberated. Heat liberation is more, due
to this tricalcium aluminate.
Tetra-calcium aluminoferrite having same reaction with gypsum and
water and gives rise to crystals.
19. STEPS INVOLVED IN
CONCRETING
Concreting involves following steps:
1) Batching of materials: It is the process of measuring the quantity of
materials required in the construction.
Pre-estimation is done before the process of any work, to save
material for avoiding wastage. Then as per the required quantity the
materials are taken.
Sand should be checked for quality, in some sand clay lumps are
present, which causes pop-outs.
2) Mixing of materials: In this process, mixing of materials; cement,
coarse aggregate, fine aggregate and water in proper proportion as per mix
ratio is done to achieve better workability and strength.
Manual mixing is done with hoe for major work and with trowel for
minor works.
Machine mixing is done by using mixer
First coarse aggregate and fine aggregate is fed in to the hopper then
cement is added, later water is poured inside the drum.
Drum is rotated for a period of rotations i.e., 2 minutes. Then the
concrete is conveyed to the site.
Water shall be added as per the proportion, if
added excess amount of water, which leads to separation of materials in
concrete, it should be in a perfect consistency.
Site mixing
3) Transporting and placing: After mixing the concrete is conveyed to the
site and placed in a wheel barrow for moving to the desired location.
If Ready mix concrete is preferred, mixing is done at the plant and
conveyed to the desired location. The drum is slightly in motion
during the transportation to do not let the concrete to stick inside the
drum.
Concrete should not be thrown from more than 1 metre height, which
results in segregation.
Mixing is done at plant
4) Compaction: This is the process of removing the air
voids present in the concrete. Air voids causes many complications.
Compaction is done by external and internal vibrators. Needle compaction
is generally done on slabs.
Problems with air voids:
There is air in the concrete, before hardening air should be removed,
because, when concrete start hardening, these air voids starts
escaping, which leave gap spaces in concrete. If we ignore this, it
results in deterioration of structure.
Rain water finds way through these gaps and creates dampness and corrode
the steel reinforcement, finally leads to structure collapse in case of reckless
behaviour of occupants.
5) Finishing: In this process, some tools are
used to make the surface smooth, level and removing the humps and
hollows.
Finishing is done by float, screed and trowel.
6) Curing: Keeping the wet condition on the concrete surface for
facilitating the complete hydration process to gain concrete a good strength.
Evaporation of water from the concrete, leads to form cracks in
concrete, so to prevent loss of water, curing is done after initial setting
time, to maintain good favourable temperature to concrete.
Curing is done by many methods: ponding or immersion, wet coverings
(using gunny bags), steam curing, membrane curing, etc.
Ponding
7) Stripping of forms: After concrete become selfsupported and attains sufficient strength, the forms are removed
20. WATER IN CIVIL ENGINEERING
“God is our source”
God created the entire universe with five basic elements they are: Water, air,
land, fire and space.
Civil engineering is mainly connected with water and land. Every structure
is to be built with these two. Don’t you believe?
Water plays vital role in construction, for instance, if you gonna construct a
building, you need cement, fine aggregate, coarse aggregate, stones, bricks.
In olden days, instead of cement they used lime. And also, the major
constituent of cement is lime, about 60 – 65%.
If you want to construct a building with all
the above is possible?... no, definitely no, because here the main
ingredient which facilitate the process of hardening of the mixture is
Water.
Without hydration process, how cement hardens.
How bricks are made without water, it is also not possible.
There is a good relationship between water and soil. Not only cement
and lime but also soil. When we add water to the dry soil, and by
mixing it, it forms like paste, we can make it into our desired shape,
and after sometime just as like cement it hardens, not almost like
cement, but some hardness.
After adding all ingredients like cement, sand and coarse aggregate to
make concrete, but without water, they won’t stick together.
To make mortar and for masonry works, water is essential.
After hardening the concrete also, we use water for curing to get a
good strength.
Water is like a person in a family, which brings life to other people. Water
shows a way for development from one form to another.
21. BRIEF INFO ON ROCKS
Rocks are formed by the result of magma. Below the earth crust, the
temperature is very heavy which makes the solid rock to appear like when a
wrought iron heating by a blacksmith how it looks likes, just like red flame.
This is below the Earth crust, rock is too hot nearly 1000 °C, which is
resulted in magma.
The magma tries to come out on the earth surface due to gases present in it
makes to move up, it creates pressure, then magma moves up, and finds the
weaker parts and erupts out from a weaker point; which is called volcano.
The magma which is came out is called lava. But sometimes magma held
up below the earth surface and it cools and solidifies, resulting the
formation of igneous rocks.
The difference between lava and magma is magma contain gases, but
lava doesn’t, because after coming out the gases escape to
atmosphere.
IGNEOUS ROCKS: The rocks which are formed by the solidification of
magma under the earth surface or above the earth surface are called igneous
rocks.
Why I said above the surface is due to volcanic rocks, which are sub
division of formation of igneous rocks.
Classification:
1) Plutonic rocks: These rocks are formed below the earth crust by the
solidification of magma. These rocks having coarsely crystallized.
Example: Granite.
2) Hypabyssal rocks: These rocks are formed below the earth surface at
short distance.
These are having small crystals.
Example: Diorite.
3) Volcanic rocks: These rocks are formed on the surface of the earth. After
the magma erupts out, this lava which contacts with air, and after cooling
it becomes these rocks.
Ex: Basalt.
SEDIMENTARY ROCKS: This type of rock is formed by the eroding by
transportation of pre-existing rocks.
The existing rocks are transported by water, wind, glacier, which resulting
in wear and tear of rocks and also some organic activities involve in
formation of these type of rocks.
These rocks are deposited at some place after eroding and combined with
some other minerals which come together which resulted in formation of
new rocks which are sedimentary rocks.
Example: sandstone, limestone.
Plutonic and hypabyssal are intrusive rocks, volcanic are extrusive rocks.
METAMORPHIC ROCKS: This rock is formed from the pre-existing
rocks under the influence of heat and pressure.
Example: Marble, slate.
Mineral is the natural inorganic material having a chemical
composition and crystalline structure. Rock is the combination of
minerals which form the earth.
22. DETAIL ABOUT SOIL - IT’S
ORIGIN - TYPES
Soil: It is a mixture of broken fine rock particles, minerals & organic matter
which formed as the earth’s upper layer.
Soil facilitates the growth of plants.
It is most essential to have knowledge regarding soil, being a civil
engineer.
Based on some theories, first earth is composed of rocks, slowly by
gradual disintegration of rocks due to weathering, the broken parts of
rocks are transported by wind, water and glacier.
Due to wear and tear action by the process of running water and glacier,
the rock pieces are further broken in to fine particles, like these, the
process going on.
Then sand is settled at some place by the above actions. In next process,
god gave birth to plants. Some plants grow in sand like cactus, Holy
basil etc.
By the dead leaves of plants falling on ground, in continuing of this
process, god created microorganisms like bacteria; which decompose the
dead leaves and convert to humus. this material made sticky nature with
sand.
Next moving living organism which is an earthworm was created by
god. The earthworms consume the dead and decayed organic matter and
digest it. The excretion of earthworm is used as manure and favours the
formation of soil with good nutrients which also favours growth of
plants.
Likes these after, god has given life to new species, they born and dead
and decayed and formed humus.
The process is continued.
Soil plays a major role in civil engineering.
Structure supported by soil in foundation, so before construction, type of
soil on which structure rests must be tested for bearing capacity.
Types of soil:
1) Laterite or red soil: This type of soil is in red colour due to the presence
of iron oxide.
2) Black cotton soil: This type of soil is in black colour due to the presence
of organic matter. This soil is having property of expansion. (Construction
on this type of soil is not suitable)
3) Residual soil: This type of soil is formed by the weathering of parent
rock.
4) Alluvial soils: These soils are formed in deposition of lakes.
23. WOOD AND ITS TYPES USED IN
CONSTRUCTION
Wood is also a vital part in building structure and plays an important role.
So, some care must be taken in selection of wood.
Uses of wood:
It is used for making doors, windows etc.
It is also used as formwork, such as scaffolding, shuttering, centring
and props.
It is used for making furniture; like chairs, desks, cupboards, shelves,
tables etc.
It is also used for constructing small bridges, houses and also used as
railway sleepers.
Timber is the one which is used as formwork, in the view of its advantages.
It is tough, durable and non-observant.
It is used in scaffoldings and for shuttering and centring works.
Teak wood is used for making doors, windows and other furniture for good
appearance.
It is very strong and durable.
Some woods like plywood having water absorption property, it bulges
after water falling over it.
IF YOU CUT ONE TREE, THEN PLANT ANOTHER TREE – Save
Environment
24. ESTIMATION OF R.C.C BEAM –
QUANTITY & COST
Beam is the horizontal structural member, which supports the roof and
distribute the load to columns.
Here, I’m considering a doubly reinforced beam of span 3m. all covers =
25mm.
Width = 0.23m, Depth = 0.3m.
Total volume of beam = 0.23 x 0.3 x 3 = 0.207m3
There are two bars at top of
diameter 12mm. and bottom two main bars of diameter 16mm. one cranked
bar of diameter 16mm.
Steel bars calculation
1) Volume of two top bars 12mm diameter (0.012m)
Length of bar = Total length of beam – side covers
L = 3 – (2 x 0.025) = 2.95m.
Volume for 1 bar
x 0.0122 x 2.95 = 3.33x10-4 cubic metre.
For two bars volume = 2 x 3.33x10-4 = 6.67 x10-4 cubic metre.
2) Volume for bottom two bars of 16mm diameter
Volume for 1 bar
x 0.0162x 2.95 = 5.93x10-4 cubic metre.
For two bars = 2 x 5.93x10-4 = 1.186x10-3 cubic metre.
3) Volume for cranked bar of 16mm diameter
Crank length is additional, because bar cranks at 45 degrees.
Total length = 2.95 + 2x0.42D (D = total depth – (covers + bar diameter))
= 2.95 +2 x 0.42 x {0.3 – (0.025 +0.025 + 0.016)} = 3.146 m.
Volume =
2
-4
x 0.016 x 3.14 = 6.31x10
cubic metre.
Weight of bar formula = D2/162.2
12mm bar weight per metre = 0.88kg/m. 16mm bar weight = 1.57kg/m.
8mm bar = 0.395kg/m.
1) Total weight of 12mm bar in beam = 2 x 2.95 x 0.88 = 5.192 kg.
2) Total weight of 16mm bar in beam = 2 x 2.95 x 1.57 = 9.26kg
for cranked bar = 3.14x1.57 = 4.93kg.
So, 9.26 + 4.93 = 14.19 kg.
Stirrups of 8mm diameter and number of stirrups = 15. Here hook bent
length extra is added.
Length of one stirrup = 2 x {(0.23-0.025) + (0.3-0.025)} + 2x12x0.008 =
1.152m.
Total length of stirrups = 15 x 1.152 = 17.28m.
Volume =
x 0.0082x 17.28 = 8.68x10-4 m3
Total weight of stirrups = 17.28 x 0.395 = 6.82kg.
Cost calculation for steel
1) Price for 1kg of 12mm diameter bar = 0.45 dollars.
So, total weight x price = 5.192 x 0.45 = 2.4 dollars.
2) Price for 1kg of 16mm diameter bars = 0.48 dollars.
So, total cost = 14.19 x 0.48 = 6.81 dollars.
3) Price for 8mm bars per kg = 0.42 dollars.
So, total cost = 6.82 x 0.42 = 2.9 dollars.
Total cost for steel work = 12.11 ≈ 13 dollars.
Concrete volume calculation
Total volume minus steel volume = concrete volume.
-4
-3
-4
Concrete volume = 0.207 – (6.67 x10 + 1.186x10 + 6.31x10
-4
+
3
8.68x10 ) = 0.203m
I have taken M25 grade concrete; ratio 1:1:2. So, 1+1+2 = 4 (for
calculation)
Volume of dry concrete is 1.54 times the volume of wet concrete. So, 0.203
x 1.54 = 0.31 m3
Cement calculation:
Volume =1 x
x 1440 (density of cement is 1440kg/ m3)
= 111.6 ≈ 112 kg. (Cement cost is 128$ per
tonne).
(1 Tonne = 1000 kg
So, total cement cost = 0.112 x 128 = 14.4$
Sand Calculation:
Volume = 1 x
x 1600 (Density of sand is 1600kg/ m3)
= 124 kg (Sand cost = 25$ per tonne)
So, total cost of sand = 0.124 x 25 = 3.1$
Crushed stone 20mm size calculation:
Volume = 2 x
x 1500 (Density of crushed stone is 1500kg/ m3)
= 232.5 ≈ 233 kg. (Crushed stone cost = 28$ per tonne)
So, total cost = 0.233 x 28 = 6.53$
Water required is based on water cement ratio. For instance, 0.6, then 0.6 x
112 = 68kg or litres
Water is generally available for free maximum, for construction.
TOTAL COST FOR BEAM = 38$
25. PAINTS
Paint: It is a fluid made up of many materials and minerals; which is
applied on the surfaces for the following reasons:
It is applied on the wood, metal, walls for protecting them from
atmospheric effects.
It makes the surface better, good aesthetic appearance.
It makes the surface smooth and shiny.
Enamel paint: It is a paint, which is
having oil substance and applied on metals and wood.
This is an oil paint.
Emulsion paint: It consists of synthetic resins and
polyvinyl acetate. This paint dries quickly and give longer service. It is
applied on walls of buildings. This is water paint.
Varnish: It is a resin dissolved with a liquid
and applied to wood, metal. It is for glossy finish and shiny surface.
26. IMPORTANCE OF SURVEYING
The word survey means, the action of detail examining of something to
collect some data regarding it, and note down.
In my words, it is a “FOUNDATION
FOR AN AIM”
Surveying in civil engineering is of three stages:
1) Detail examination of an area.
2) Collection and recording of data.
3) Interpret in the form of a plan or a map or any descriptive details.
Before construction of a road, building or any other structure, we have to
know the details about the place of construction, for instance, consider we
are going to construct a road, which involves the following.
Going to the site and examining the area, and finding the feasible route
for road construction by considering distance, cost of construction,
connecting places etc.
The best route is selected and levels are taken using some instruments
like auto level or dumpy level.
After collecting the data, plans are prepared for further process.
There are instruments used in surveying operations are: Theodolite,
tacheometer, dumpy level, auto level, Total station, G.P.S device.
For measuring horizontal distances and angles (horizontal angles at
curves).
For measuring vertical distances (Taking levels).
For calculating area.
For calculating volume of earthwork.
27. HOW TO CALCULATE AREA OF A
PLOT
Area calculation is a very basic one, but involves some confusedness.
We can easily measure area of a plot by some methods. If the plot is of
regular dimensions, it means square or rectangular, it is easy to measure
with chain or a tape. Generally, we measure with tape for smaller areas.
For example, an irregular plot shown below. How to calculate area in acres?
The area is irregular, a little difficult to calculate the area. In this case you
have to divide the area in to different parts for easy calculations. Name
them as 1, 2 etc.
Like this second picture.
Converting inches to feet for easy calculation, then
74 ’ 5"= it means 74 feet, 5 inches
1 feet = 12 inches, then 1 inch = 1 /12 = 0.083 ft.
So, 5 ÷ 12 = 0.4167
74.4167 ≈ 74.42ft. (approx.)
1) Area of 1st one = 74.42 feet x 85ft. = 6325.7 sq. ft.
2) Area of 2nd one = 30ft x 20ft = 600 sq. ft.
3) Area of 3rd = 16.67 x 15.58 = 259.72 sq. ft.
4) Area of 4th =
x 16.67 x 14.42 = 120.2 sq. ft.
Total area of plot = 6325.7 + 600 + 259.72 + 120.2 = 7305.62 square feet.
For converting in to acres (1 acre = 43560 sq. ft.) = 7305.62/43560
= 0.168 acres.
In sq. yards (1 acre = 4840 sq. yards). = 0.168 x 4840 = 813
sq. yards.
Unit conversions are necessary for calculations, which are given in part 1
book.
Actually, the above calculated area is of smaller size, for bigger
areas, some instruments like theodolite, total station, G.P.S etc. are
used.
G.P.S method: In this the G.P.S device is taken and by selecting the area
calculation option in it and starting walking at the border of area around
with this device, and coming to the starting point.
For getting the complete area of plot with less effort.
28. DEMOLISHING
The process of destructing a structure with good techniques for safely
collapse, without cause effects to other structures and people.
When the structure became deteriorated and not safe for occupants, then it
has to be demolished.
In some cases, if building is exteriorly good, then only interior walls,
ceilings were removed and remaining were not.
If the total building has to be tear down when reached deterioration
state, then hydraulic excavators were used.
Now a days, crane and wrecking ball is using for demolishing, which
is best equipment for this purpose.
Sometimes, explosives like dynamites were used for demolishing.
If the material of structure is satisfactorily good, in this case some
techniques were used for dismantling the structure and without causing
much damage to materials, for recycling purpose.
29. CENTROID, CENTRE OF GRAVITY
Centroid: This is the centre point of a surface or an object.
Centre of gravity: The point through which entire weight of a body is
concentrated.
Example: Take a book and keep your one finger below it, the point at which
the book stays in balance position without falling down, is called centre of
gravity point, of the book.
30. DETAIL PROCESS OF BULDING
CONSTRUCTION
Selection of site.
Surveying operations.
Planning.
Designing.
Estimation.
Execution
1) Selection of site: Before the construction, it is very mandatory to select
the site, without site where building is constructed.
2) Survey operations: In this, there are two stages.
In first stage; the area is calculated and noted the details about
dimensions of area, availability of infrastructures, and possible routes to
our destination point for transporting materials, nearby buildings.
In second stage, Geological study: To know which type of foundation;
rocky or soil, whether the structure can rest in that foundation or not. The
type of rock soil test is conducted for knowing the safe bearing capacity
of soil. in this, soil type, bearing capacity, porosity, water absorption.
Some information regarding site is noted for design of building.
3) Planning: In this stage, detail plan of building is drawn as per a suitable
scale; showing the details of walls, placement of windows, ventilators,
doors and their dimensions. Car parking spaces, setbacks etc. some other
details are given in the plan.
Electrical connections layout plans, water supply and sanitary connections
plans are also prepared.
4) Designing: Designing is done architecturally and structurally. (It is a plan
in brief)
In architectural design we can see the complete building with realistic
look and can make videos and pictures of it. It consists of detail showing
how exactly the building after construction looks with all accessories.
Exterior designing consists of walls 3D, gate, car, bench, wall
lamps, swimming pool, paint for walls, paved area, garden, lawn
etc.
Interior designing: Doors, windows, ventilators, lamps. And some other
following: In hall – Isabel sofa, ceiling fan, type of floor (stone or tiles), classic floor
lamps, wall lamps, aquarium, television, shelves etc.
In kitchen – sink, wash basin, refrigerator, cooking platform, oven,
cupboards, shelves etc.
In bedroom – beds, mirrored dresser, laptop, bureau, child’s nightstand etc.
In bathroom – bathtub, shower, washbasin, wall mirror, taps etc.
In restroom – urinal bowl for men, bidet for woman, water closets, taps etc.
Some software for architectural design is Revit architecture, dream
plan software.
Structural design: The design details are prepared based on bearing capacity
of soil, loads acting on the building etc.
Based on shear force and bending moment values, the steel
reinforcement details are come out, and type of concrete mix to be used
also come as output.
Software’s used for structural design are Etabs, staad pro.
5) Estimation: It is the process of calculation of quantity and costs of
various item of work based on the design details produced.
The quantity of every element like column, beam, slab is calculated.
And finally based on the rate per one number or per m3, the total cost
is calculated.
It is very important to know about the total cost required for the
construction.
6) Execution: This is the finale action performance based on the all plan,
design details.
First, the site area is cleaned and levelled properly, then centre
markings on the ground is carried out based on plan and design
details. Further process is carried…
31. MECHANICAL PROPERTIES OF
DIFFERENT MATERIALS
Materials having differ properties which are useful to us in many cases.
Elasticity: The property of a body which regains to its original size and
shape after the removal of force.
Example: Rubber.
Plasticity: It is the property that, the material will not regain to its original
size and shape after removal of force. It undergoes deformation.
Example: clay, plastic, steel rod etc.
Ductility: It is the property of material, by which the material drawn in to
thin wires shape on the application of force. The property of material which
stretches on applying tensile force.
Example: Mild steel, aluminium
Brittleness: The property of material in which the material breaks on the
application of load.
Example: Glass, ceramics.
Here, a pot breaking by
an athlete, which was me
Malleability: It is the property in which the material is hammered in to thin
sheets without rupture, on application of loads.
Example: Copper, mild steel, gold.
Creep: It is the gradual deformation of material on normal loading.
Example: concrete.
Toughness: It is the property of material which resist the load and absorb it
without fracture.
Example: Mild steel.
Stiffness: It is the property that the material does not bend on application of
force. It is resistance to bending.
Example: concrete block.
Hardness: It is the property of material resistance to scratching or abrasion.
Example: Diamond.
32. TYPES OF ROAD PAVEMENTS
There are two types of pavements:
1) Flexible pavement.
2) Rigid pavement.
Flexible pavement: It is the type of pavement, in which it behaves as an
elastic material on normal loading; it deforms and regains to original shape
after removal of load.
On heavier loading, it results in forming potholes.
Ex: Bituminous road, earthen, water bound macadam roads.
Rigid pavement: It is the type of pavement, which resists the normal
loading without any deformation. On heavier loading, it permanently
deforms and results in cracks
Ex: cement concrete roads, prestressed concrete road.
33. INFORMATION ABOUT RAILWAY
AND ITS COMPONENT PARTS
Railway is the means of transportation through trains on rails. First worlds
railway steam engine was started in England by George stephenson in 1814
between Stockton and Darlington.
Advantages:
1) Railways are cheaper, safe and faster mode of transportation than
roadways.
2) Heavy goods and other materials from various countries can be exported
and imported through railways.
3) Railways are quicker, so people can go to their destination quickly with
comfort.
4) All facilities available in passenger trains for passengers, like restrooms,
pantry, sleep etc.
5) People from various places can migrate to another place easily with
affordable price ticket.
Component parts of railways:
Train.
Rails.
Sleepers.
Ballast.
Spikes.
Fish plates and bolts.
Train: It is the vehicle which moves on rails by
wheels.
Rails: Rail is the component part, which is like a steel girder rests on
sleeper which is fixed by fasteners. It distributes the load from train to
sleepers.
Flat footed rails used maximum in the world, which are invented by
‘Charles vignoles’
Gauge is the inner distance between the two faces of rails.
World’s standard gauge is 1.435m.
Sleepers: These are laid laterally in track. Rails are supported on these
sleepers.
Sleepers distribute the load from rails to ballast.
There are wooden, cast iron, steel, concrete, R.C.C, prestressed sleepers.
Ballast: It is the broken coarse stone, which is laid below the sleepers to
distribute load to the foundation. It gives lateral and longitudinal stability to
the track.
It holds the track in form position for not getting track disturbed due
to train speed.
It distributes the load from sleepers to subgrade.
Provides good drainage and It does not let vegetation to grow.
Spikes are used as fasteners for wooden sleepers. For metal and concrete
sleepers - Pandrol clips were used.
Spikes
Pandrol clip
Between two rails, fish plates and bolts used to fasten rails.
34. CAUSEWAY
Causeway: It is a way, which is raised on wet ground or watercourse, used
for road or railway purpose. It is made of concrete, wood, soil etc.
It is a submersible bridge; water may flow over it during flood period.
This structure is constructed in economical point of view, when there is
much cost to be spend for a bridge.
35. ESTIMATION & SPECIFICATIONS
Estimation: It is the process of calculating the quantities and costs of
various items of work required for the construction.
Need of estimation:
Before the construction To know number of doors, windows, ventilators, gates required for building.
To know the quantities of each item of work such as quantity of cement, fine aggregate,
coarse aggregate, water in concrete and quantity of steel for reinforcement.
To know whether the funds available are being sufficient or not to complete the project.
To know number of bricks required for walls.
To know the exact cost of each item of work.
To obtain administrative approval and technical sanction.
Specifications: It is the detailed description of materials and design of
structure. This makes to know quality of materials used in work.
Quality of materials like, proportions of cement concrete, mortar and
method of mixing and transporting to site, quality of steel, type of
formwork; steel or wooden.
36. TENDER, QUOATATION,
CONTRACT, TENDER FORM, TENDER
NOTIFICATION
Tender: It is the proposal in a written form to carry out a work or supply
goods for a fixed amount of money.
Quotation: It is the statement of an estimated cost for a work. It is
submitted by the tenderer for getting contract for a proposed work.
Contract: It is an agreement between two people
legally, for some purpose.
Tenderer: He/she is the person, who submit tender.
Contractor: The person who gets the contract.
Tender notification: It is a notice published in newspapers or circulated
through any electronic means like bulletin; for getting offers from
contractors for a proposed work. It is a written form which consists of
Name of project or work, place & date of submission of tender, estimated
cost, contact, cost of tender form, tender document link to download,
earnest money to pay are given in that notice for invitation.
Tender form: It is the form, which is submitted by the tenderer after filling
all details; how much he/she quotes for concern work and along with this,
the tenderer has to pay earnest money also.
Form: It is like a letter for confirming his/her intention of offering the work
for certain amount of money and its time completion, accepting conditions
of contract, bankers name, partners name and address, signature. And also,
payment of earnest money as a security deposit. If tenderer gets the
contract, the it is considered as 2% security deposit, if he/she doesn’t get
contract, then the money will be returned.
Tender document: It is the whole document consists of everything such as
notice of invitation, information about work, rules and instructions to
tenderer, safety code, conditions of contract etc.
After the acceptance of one’s contract, the contractor has to pay 8% from
the total value to work as security deposit; it means total of 10% from value
of work is kept as security deposit.
37. PRECIPITATION & ITS FORMS RAINFALL TYPES
Precipitation: It is the condensation of water vapour in atmosphere from
clouds and falls under gravity on earth in different forms.
Forms of precipitation:
1) Drizzle: It is the light rain; fine drops of water. It is slower falling due to
very small size droplets.
2) Rain: It is most appearing form of precipitation in which falling of water
droplets of diameter from 0.05mm to more.
3) Sleet: It is small ice falling on ground. Having size lesser than 5mm.
4) Hail: It is the ice having diameter 5mm or greater than that. These are
like small balls, which falls during thunderstorms or with normal rain.
5) Snow: It is the frozen water vapour in atmosphere having white colour,
which falls on ground slowly. It is having less density than rain.
Types of rainfalls:
1. Cyclonic rainfall: This occurs from the cyclone effect, due to the
large-scale air masses rotates in sea, creating low atmospheric
pressure at centre, then warm air rises and form clouds resulting
continuous rainfall with lightening, thunders and sometimes tornadoes
etc.
2. Frontal Rainfall: It is the type of rainfall, which occurs due to cool
air mix with warm air.
3. Convective Rainfall: This type of rainfall occurs when moist air over
the ground warms by the heavy temperature, then it is forced to move
up and form clouds and by condensation it resulted a rapid rainfall
over a short period of time.
4. Orographic Rainfall: This type of rainfall occurs at mountain
ranges, due to obstruction of mountains, the air moves up and expand,
next air cools adiabatically; which means decrease of heat in air and
cooled by change in pressure, resulting in forming clouds and
precipitation occurs at windward side.
38. CONCEPT OF RAFT FOOTING
Function of footing is to distribute the load from the columns to the
foundation soil.
Why we use raft and where?
Raft footing is adopted in some areas, which are having soil of poor
bearing capacity and causing settlement.
A query – How raft makes it possible?
Stress = load/area
If a load of 100KN is acting on an area of 2m2, then stress = 100/2
= 50KN/m2
If same load of 100KN is acting on an area of 10m2, then stress = 100/10
=
10KN/m2
If area is increased, the stress decreases. For example, if a task is
undertaken by a single person, it causes much stress on the person. If the
task is shared by many people, then no stress on everyone, task will be
completed easily by sharing work.
Examples:
Procedure:
1) Place a brick vertically on a container containing sand. You’ll observe
that some sinking of brick inside the sand. Measure the depth of sinking.
Next, place the brick in horizontal position on the sand, this time you’ll
see depth of sinking is much lesser than former one.
Why? Because, distribution of load through larger area results in less
stress acting on the area. So, depth of sinking in vertically placed brick is
more than horizontally place one.
Vertically placed brick
Horizontally placed brick
You can also simply understand this by another example, see in pg. no. 7.
In that, I have placed a steel sheet in horizontal position slowly on water, it
floated without sinking. If I place it in vertical position, it will definitely
sink due to breaking of cohesion between molecules, because force acting
at a single point. By horizontal placement it shared the force on large area,
so no sinking.
THINK AND CONDUCT THE EXPERIMENT PRACTICALLY, YOU’LL
CLEAR
39. STAIRCASE – TYPES - TERMS
Staircase is a structure having steps and support railings to access from one
floor to another floor. It is the vital one in a building.
If you want to move from one floor to another floor, we need stairs.
Types of staircases:
1) Straight flight staircase: It is the type of staircase in which stairs are
provided with one direction without turns, with or without landing.
This is provided when there is more place.
2) Quarter turn staircase: This type of staircase turns 90 degrees either
right or left. Winders or landing is provided at turning.
a) Better appearance with these stairs.
3) Half turn staircase: This type of staircase turns 180 degrees either right
or left, provided with landing or winders at turning. In these stairs one
flight is opposite direction to another. These are of two types.
a) Doglegged staircase: In this staircase no space is provided between
two flights.
b)
Open well
staircase: In this type, some space is provided between two flights.
Space for light and air.
4) Bifurcated staircase: In this staircase, the bottom flight is wider and
divided in to two narrow flights at landing, opposite to each other.
It is generally used in public, assembly buildings
5) Geometrical staircase: This type of stairs well is of curved shape, the continuous stairs which
turn or wind around a central well hole, having rounded or elliptical corners with railings also,
but no newel post.
It may be like arcs, elliptical or square types, name itself says,
geometry; decorated with lines and shapes.
6) Circular staircase: This type of staircase is in circular shape; railings are provided continuous
up to access to another floor, and at turning direction winders are provided.
This type of staircase says, it is in circular one.
NOTE: If the stairs are radiated from a central
newel, then the staircase is known as spiral staircase.
Terms used in staircase:
Step: It is the part of stair, consisting tread and riser. It is the one on
which we place our foot for moving up and down.
Tread: It is the horizontal top surface of step on which our foot is
placed.
Riser: It is the vertical face of step.
Soffit: The under surface of stair is called soffit.
Hand rails These are provided inclined or horizontal in staircase, which
are above the steps supported by balusters. These are used for supporting
the users, like an assistance for not to slip.
Balusters: These are the vertical supporters for railings, which are kept
between steps and handrails.
Newel: It is the post, provided at bottom, top and at turnings in a stair
for supporting railing. It is provided centrally in spiral staircase for
radiating stairs.
Landing: It is the horizontal platform provided between two flights for
relaxing of users.
Flight: The series of steps without change in direction. Distance
between floor and landing.
Nosing: The projection of tread beyond the riser is called nosing. It is
generally made smooth shape.
40. LINTEL & SUNSHADE
Lintel: It is horizontal support, used to support the door, window or
ventilator. It is just like a small beam, which distributes the load properly to
walls. It makes the load not to act on door and windows.
Sunshade: It is the horizontal projection from the lintel level above the
door, window or ventilator; to protect these from sun, rain etc.
41. VALVES - IMPORTANCE
Valve: It is a device for regulating the flow of fluid through a pipe.
Types of valves:
1) Sluice valve: It is also called gate valve. A handle provided at top for
opening and closing the valve. It is provided at water supply pipe
connections for a city.
It is used industrial applications like oil and gas industries.
2)
Ball valve: It is a quarter turn valve, having
hollow, perforated ball which is closed when rotated to 90 degrees by
handle, and opens when the ball hole is in line with the flow.
It is used for flow and pressure control fluids.
We can see this valve in buildings at water supply connections.
3) Reflux valve: It is known as check valve or non-returning valve. In this,
the fluid runs in one direction only and no back flow is possible due to
this valve.
It is used at the connection at home sewer line and city sewer line. In
some situations, like clogging in sewers and during heavy flood period
and sometimes due to improper drainage system, the waste fluid will
return back to building sewer pipe. In order to stop this, the reflux valve
is provided.
4) Scour valves: These valves are located at dead ends and depressions to
remove the silt and sand. This valve is placed at treatment plant.
42. CONTOURS & ITS IMPORTANCE
Contour: It is an imaginary line drawn on a map to determine the
elevations at different points, on ground. All the elevations are marked in
horizontal plane on map.
The points in the contours are taken with reference to mean sea level.
Elevation = height.
Uses:
It shows shape and slope of terrain.
It shows the elevation of the ground.
We can know, depth of pond and height of hill.
Earthwork can be estimated for roads, railways, buildings etc.
For pond, higher elevation values are outside and lower values are
inside.
For a hill, higher elevation values are inside and lower elevation values
are outside.
By this you can understand the differences.
43. ELASTICITY & PLASTICITY
These are very basic properties, but vital in civil engineering.
Elasticity: It is the property of a material, in which the material regains to
its original shape and size after removal of force.
Example: Rubber.
Take a rubber band and stretch it. What do you observe? = It stretches.
Remove the applied force, then you’ll observe its regaining to original
shape and size.
Steel bars used in construction also possess this elastic property up to
certain extent.
Plasticity: It is the property of material, in which the material doesn’t
regains to its original size and shape after removal of force.
Example: clay.
Take clay and press it. You’ll notice plastic deformation at same time.
You can also take example of plastic bottle for plasticity. Crush the
bottle by some force, it deforms and doesn’t regains to original size and
shape.
WARNING! = Crush the bottle after removing the bottle cap otherwise, it
may cause trouble for you sometimes when you trample it. ��
After some time of application of stress on steel continuously, it reaches its
plastic stage.
Look this stirrup is plastically deformed.
Yield strength of steel is the stress at which material starts plastic
behaviour.
There are some stages when you apply stress on the material.
First stage of reaction of material when you apply stress (little) = It
undergoes elastic deformation.
Second stage of reaction of material when you apply stress (medium)
= It undergoes plastic deformation.
Third stage of reaction of material when you apply stress (much) = It
results in breaking of material.
Here I'm take different materials for each property, actually every material
undergoes these three properties (elasticity, plasticity and breaking) to
understand clearly by conduction tests yourself easily, I’m using these
following examples.
You can take any material and conduct experiment. For instance, steel bar,
sometimes steel bars in concrete project outside as extra one in buildings
at columns. If you apply little force and make bar turn one side and leave,
it again regains to its shape and size.
Elastic behaviour
after plastic stage
plastic behaviour
breaking
Take another material, which is plastic bottle and
crush it. You’ll observe plasticity.
Take a glass and apply stress, the result is breaking of glass.
44. POST TENSION SLAB
Post tension slab means, the tensioning of slab after attaining sufficient
strength of 75%.
In post tensioning slab materials used are:
Tendons
Ducts
Anchors
This is similar to the conventional slab, but here tendons are placed
additionally to improve tensile strength of slab.
This type of slab makes the number of columns reduces in structure, and
provides column free spaces more, that conventional slabs fails to do so.
Ducts
Tendons
Procedure:
1) During the laying of steel reinforcement, the tendons are encased in ducts
and laid on slab.
2) One end of the tendon is fixed to anchors and another end is left open
with pocket former.
3) Grout tube is placed at anchorages for grouting finally at end of
operation.
4) The concrete is laid.
5) After the concrete attains sufficient strength of almost 75%, then the
operation of tensioning tendons at the pocket former by placing a jaw
and pulling with a force of 33,000 pounds.
6) After tensioning process, the outside portion of tendons, which are
stretched out are cut, and the surface is covered with cement mortar.
7) Then, the grouting process is done through grout tubes placed at anchors.
8) Finally, the grout pipes are tied after complete grouting and sealed.
Advantages:
Clear distance between columns are longer, so better aesthetic
appearance of building.
Slab do not crack in case of heavy loadings.
Slab is much stronger and durable.
Best suitable for garages, stadiums etc.
Thin beams in these slabs leads to reduction in cost.
Care should be taken during operation. Skilled persons are mandatory.
45. RAIN GAUGE
Rain gauge: It is a device used to calculate the rainfall intensity over a
period of time.
It records the depth of rainfall in mm over a unit area.
“One millimetre of rainfall record at a given time means one litre of water
over an area of one metre square.”
We can know the volume of rainfall over a period of time, this helps us to
use that water for various purposes by trapping and conveying through
drain system and storing the water.
But some part of water should be infiltrated to ground for recharging it.
Conditions of placing rain gauge:
It should be placed in open ground, free from any obstructions like
trees.
It should be surrounded by fencing, in order to avoid disturbance by
cattle sometimes.
It should be placed on level ground, not on sloped terrain.
Types of rain gauges:
1) Graduated cylindrical rain gauge: It is the standard rain gauge, in this,
the graduations are marked to measure the readings directly. The rain
water passes from funnel to the cylinder, we can measure rainfall easily.
2) Tipping bucket type rain gauge: In this type, rain gauge looks like
seesaw, water first collects by funnel and then it is passed through a pipe,
finally there are two buckets placed opposite to each other, the water
from pipe is filled into one of the buckets, then it goes down due to more
weight and other bucket goes up like seesaw. After bucket goes down it
trigger a switch, which send signals to base station. After each time of
drop, it sends signals. Number of tips are noted.
3) Weighing bucket type: In this, receiving bucket is mounted on weighing
device. The amount of compression made by bucket used for calculating
weight of water.
By mechanical means, a spring is placed below the bucket and a
pen attached to one side of spring for recording data on a rotating a
drum on which a chart is mounted shown below.
This type of rain gauge can measure the hail and snow also.
46. CATCHMENT AREA & RUNOFF
Catchment area: It is the area of land with water created by rainfall during
a storm. This water is flowed into rivers or streams etc.
Runoff: It is the flow of water on the ground, resulted from a heavy rainfall
after all losses (infiltration, evaporation, absorption by vegetation) have
been taken place.
47. WHAT IS IRRIGATION
“Supply of water to the fields for the cultivation of crops is called
irrigation.”
Irrigation also helps in many ways such as
By constructing dams, canals etc., we store water during rainfall and
utilize it for many purposes like growing crops for enrichment,
drinking, washing, electricity generation, fish growth etc.
When water is not sufficient for growth of crops, the stored water is
carried to the place of cultivation by some methods.
Irrigation is done by following methods:
Irrigation by rain: The natural rain irrigates the crops and trees.
Artificial methods:
Furrow irrigation: In
this method, furrows of long narrow trenches of 10 – 25 cm deep are
made and water is supplied through them. Generally, furrows are spaced
at certain distance between each.
Basin flooding method: In this method, ditches are made for flooding
water. Water is supplied from supply channel to ditches.
It is suitable for crops like cereals and trees like banana, citrus
fruits.
Sprinkler irrigation: In this method, sprinklers are provided to pipes
for spraying the water.
Drip irrigation: In this type of irrigation the watering is done near the
base of plant. It reduces water wastage and enrichment of crops can be
seen with your naked eye.
This is the best efficient method.
48. 3D HOME PLAN DESIGN BY
DREAM PLAN SOFTWARE
This software enables the user with a quick access gaining by tutorials and
we can easily understand and make 3D home models.
It is simple and user-friendly software.
Procedure for a 3D building design:
Open dream plan software.
Next click on trace floor plan.
Then click on ‘Start trace wizard.’
Click on ground level and next floor plan.
Browse for your plan pictures which is made by auto cad or any
other.
Click next, and start calibration. See picture below.
Draw lines on your plan, same like redrawing the plan, shows thick
lines.
Click next after adding lines and go to building and add walls (give
thickness).
Then you add internal walls with your own preferred internal wall
dimensions including height.
Change to view to 3D.
Finally adding accessories section, it’s very easy.
You can add the following:
Doors = Glass entry door, three panelled door, interior utility, exterior
door, door frame, sliding glass door, garage door etc.
Windows = 3 panel sliding, 9 panel square window, awning window,
plastic window etc.
Floors types = wood slat, wave tile, clay, granite, marble, concrete,
stainless steel etc. and different colours also available.
Roof = Different colours, types of materials and eaves size and also
slope angle provided.
Staircase and railings are provided and paint option is also available.
Exterior accessories like plants = Beach tree, palm tree, tomato plant
etc.
Lighting = wall lamps, classic floor lamp, table candles, track
lighting, ceiling lamp etc.
Electronics = laptop, television, keyboard, phone etc.
Appliances = oven, refrigerator, mixer, meat slicer, coffee maker,
restaurant soda fountain, gas stove, dish washer etc.
Plumbing = Bath tub, shower, sink, wash basin, bidet, classic toilet,
men’s urinals etc.
Furniture = different types of Beds, executive chair, conference office
chair, restaurant chair, child’s nightstand, mirrored dresser, armchair,
Isabel sofa etc.
Ceiling fans, teapot, aquariums etc. everything you can get in it.
You’ll pleased finally.
49. DETAIL ON CAUSES OF CRACKS,
PREVENTIVE MEASURES AND
REPAIRING METHODS
Cracks are caused due to many reasons such as:
Bad quality of materials used in the construction: Some people use
low quality materials in the construction to decrease the initial cost, but it
leads to increase cost for repairing the structure finally.
1) Sometimes sand contains clay lumps, which causes small holes on
concrete. (pg.105)
2) Some woods will absorb moisture and also shrinks on certain
temperature. Some type of woods expands in winter and shrinks in
summer; this leads to crack between wall and window or door frame.
Defects in workmanship: Lack of skilled labour and supervision leads
to improper handling of material.
1) Improper stripping of forms, hitting with much force in removal of
forms leads to
internal cracks in concrete.
2) Improper arrangement of forms, which leads to leakage of concrete.
3) Throwing the concrete from more than 1 metre height.
4) Improper mixing of materials and improper finishing.
5) Improper mortar joints between bricks in walls.
Poor foundation soil: Due to weak or loose soil, settlement will occur
after the construction and results in cracks. Some soils like black cotton
is having property of shrinkage and expansion which results in
foundation failures.
Improper mixing ratio: Mixing of materials not as per the given ratio,
leads to cracks.
Use of more water in mix: In some cases, workers mix more water in
concrete to increase workability and to complete quickly, but more water
in the mix leads to separate the materials without a good bond.
Less water content in the mix: Less water content leads to honey
combing; looks like voided concrete.
Heavy temperature: During concreting process, heavy temperature
leads to plastic shrinkage on top of concrete by the loss of water in the
form of evaporation from concrete.
Improper design: While executing work, improper design leads to
deflections of slabs and beams, unstable structure, finally sometimes
collapse.
Improper curing: Improper curing leads to incomplete of hydration
process and structure attains poor strength and forms cracks.
Bubble formed due to water penetrating
inside R.C.C slab during rainfall
Water penetrating from poor joints in staircase
Small hole on Reinforced concrete slab formed due to clay lumps present
in sand
Preventive measures:
Cracks can be prevented by the following:
Use good quality of materials.
Skilled supervision is necessary in any type of construction.
Leakage of forms due to improper arrangement is minimised by
recheck after arrangement.
Sand should be checked for quality and sieved before construction to
avoid clay lumps and other debris.
Curing should be done properly.
Design of structure must be rechecked before construction.
Using water content in the mix as per the given ratio.
Proper sloping on the top of roof towards one side is essential to
drain off the rain water automatically. (stagnation of water result in
forming algae, which boost the dampness process)
In laying of stone or tiled flooring the joints between each piece must
be leak proof by good bonding.
Note: “There will be no repair required after the construction of building,
this is only happened when everyone including workers, engineers,
supervisors etc., whoever there in the construction are must be skilled and
having technical knowledge about civil engineering.”
Skilled and knowledgeable person manipulate everything based on
situations. For instance, in laying of a concrete slab, if temperature is too
high, unskilled workers and supervisors directly do. But skilled persons will
do; using ice in water, making water cool and using cool water.
As normal water evaporates easily than the cool water and leads to plastic
shrinkage easily.
Repairing methods:
1) Spalling: Spalling means removal of layer of surface due to dampness.
Spalling is formed on concrete surface and plastered wall surface due to
dampness.
If more water is stagnating on concrete slab at a place every time,
after some period, finally it leads to penetration of water inside the
concrete and causes dampness and resulting spalling, which you can
clearly observe at bottom of slab.
By the exposure of steel reinforcement, it
causes corrosion to steel, so spalling area should be repaired immediately.
Similarly, it also occurs to walls due to penetration of water through joints
or any other entry.
Procedure:
1) If spalled surface is RCC, then clean the spalled surface with wire
brush to remove rust if any on steel bars.
2) If steel bar is completely corroded, then add rebar and tie it to the
corroded bar with binding wire. Then you can start applying mortar.
3) Mix cement, fine aggregate with a ratio of 1:3 and water cement ratio
= 0.5
4) Add some water proofing chemicals for more durability (for instance,
Dr.fixit 301).
5) Before application of mortar, sprinkle some water on the surface
where mortar to be applied.
6) Apply the mortar with trowel and finish it properly.
7) Cure it by sprinkling water to get good strength.
Note: In order to avoid the problem permanently, you have to stop the
problem of source, I mean where it occurs from. So, avoid stagnation of
water on the roof or joints of walls. Water also penetrates from joints of
stairs also.
Penetration of water mainly occurs through joints, so ensure that joints are
leak proof during construction. Actually, more heat is liberated during
hydration of cement, so cement shrinks without sand. Sand is essential in
mix.
2) Hair line crack: These hair line cracks are caused due to deflection,
temperature stresses or
any other reason. Hair line cracks are risky to repair, if repairer is not
skilled it cause many
complications.
Hair line crack can be repaired by epoxy injection or if this is not workable,
we can prefer other method.
Epoxy resin and hardener used for repairing cracks with grout inject.
Both are mixed and applied.
Procedure:
Drill the crack from the concrete face.
Inject water to flush out defect
Allow surface to dry
Making the holes of 3/4 inch diameter, then pipes are fixed along
crack.
Epoxy is injected through holes of pipe.
Even though you have used epoxy, but sometimes due to improper
procedure it doesn’t works. In some cases, the crack may be looks like a
break line; half cracks appear half didn’t; just like a centre line of road. In
this case you have to choose 1-inch groove cut by chisel method.
Procedure:
Clean the surface and sprinkle some water over it (to avoid fine
concrete fragments fall on us). Take a chisel and hammer and wear
goggles and hand gloves. start grooving about 1-inch width and ½
inch depth.
Chisel should be placed to 45 degree, then hammered.
After making groove, sprinkle some fine sand over it for good bond
with new coat, then start applying cement mortar (sand passed
through 100 microns sieve) with Dr. fixit URP 301 (water proofing
material). For 1kg cement, sand is 0.5kg and dr.fixit 301 URP is
200grams, water is added up to good consistency, no excess water.
Next day, apply brush coat of cement, little fine sand and dr. fixit 101
with smooth finishing.
Later curing is done by ponding method to attain good strength.
Done by me for my slab
Method of application depends on type of work, situation and
condition.
All we know “prevention is better than cure.” So, taking precautions during
construction is better than repairing after construction.
?=
Calculate the exact density of coarse aggregates with a simple experiment
i.e., given below.
Take an empty cylindrical container of good shape, then measure its
dimensions.
Measure the weight of empty cylindrical container and note down
(W1).
Place the sieved coarse aggregate (certain size, generally 20mm) in
the container.
Remove excess aggregates and level it properly and measure the
weight and note down (W2) this weight including container also.
Calculation:
Calculate the bulk density of coarse aggregate (including voids) =
For instance, I’m taking some values here for calculating. W1= 4.5kg, W2=
12kg, V = 0.005m3
= 1500kg/m3
So, bulk density of coarse aggregate (including voids between aggregates) =
1500kg/m3
To find the true density, following procedure is followed.
Take the same container with aggregates filled completely.
Take a measuring jar with water.
Next, add water in the cylindrical container by pouring up to the level
of container until completely filled the voids between aggregates.
Measure the weight and note down as (W3).
Pour until the water reaches top level of container, then note down
how much water is poured by measuring jar in ml or litres (through
which you poured water).
Measure its weight and note down as W3.
Next calculations.
Calculation:
TRUE DENSITY =
To calculate true density of coarse aggregates (Excluding voids) =
W3 = Weight of water + weight of coarse aggregate + weight of container.
W2 = Weight of coarse aggregate + weight of container.
W1 = Weight of empty container.
In my calculations, W3 = 14.2kg.
For knowing volume of water filled, W3 - W2 = 14.2 – 12 = 2.2kg.
Also, we can know by this, volume of water filled (2.2 kg of water is
poured, noted by measuring jar).
So, generally 1kg water = 1 litre at 4 degree Celsius, I’m taking here also
the same, as it doesn’t cause any incorrect results.
2.2kg extra weight, which is filled by water. So, 2.2kg = 2.2 litre =
= 0.0022m3 (convert in to m3). Deducting extra volume (spaces between
aggregates, which is known by water volume in that container).
=
= 2678 ≈ 2700kg/m
3
Finally, true density of coarse aggregate is 2700kg/m3.
REMEMBER ONE THING EVERY
TIME
“For solving a problem, find its
source to get permanent rid from it”
My ….
When I was 19, I had written the book, ‘Basic knowledge in civil
engineering.’ Actually, I had written when I was a student of Bachelor of
technology in civil engineering third year.
Our brain will remember the things more precisely, which we have seen it
with our naked eye, rather than we imagined it.
I have faced this problem during my education, so to avoid this problem
for other students, I have written this book.
Therefore, to avoid this problem, pictures and examples are given to the
particular topic, which makes easily to understand and remember forever.
My second book which is Non-Fictitious – Fiction Book = P+P: (Journey
of a Boy).
This is my third book. I hope this book pleased you.
NOTE:
Every person in the world is born with a unique talent, so notice your talent
yourself and go forward towards accomplishing your goals, if others fail to
recognize your talent.
“And also remember one thing, marks, degrees won’t come with you
always, but the talent you have makes others to come near you”
ATTENTION PLEASE!
World is going in a hurry manner daily. People are
often saying busy – busy.
The body is said to be in equilibrium condition, when
opposing forces acting on the body are balanced.
Here, people are only experiencing forces mentally,
but not physically. So, resulting in different types of
diseases, even to young people. Lack of physical
exercise leads to many problems.
Do exercise daily and balance forces acting on your
body.
Our human body organs have different roles and
functions, when their performance decreases are only,
when you simply sit and work mentally without
physical exercise daily. So, do exercise daily to avoid
worry.
PHYSICAL + MENTAL = BALANCED
KINDLY WRITE A REVIEW FOR
THIS BOOK IN AMAZON
Thank you
My email id:
narasimhavavilala@gmail.com
YouTube: NR Civil engineering.