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CE2203CONSTRUCTION TECHNIQUES, EQUIPMENT AND PRACTICES 4 0 0 4
OBJECTIVE
The main objective of this course is to make the student aware of the various construction
techniques, practices and the equipment needed for different types of construction activities. At
the end of this course the student shall have a reasonable knowledge about the various
construction procedures for sub to super structure and also the equipment needed for
construction of various types of structures from foundation to super structure.
UNIT I CONCRETE TECHNOLOGY 12
CementsGrade of cements - manufacture of cementconcrete chemicals and ApplicationsMix design conceptmix design as per BIS & ACI methodsmanufacturing of concrete
Batchingmixingtransportingplacingcompaction of concretecuring and finishing.
Testing of fresh and hardened concretequality of concrete - Nondestructive testing.
UNIT II CONSTRUCTION PRACTICES 13
Specifications, details and sequence of activities and construction co-ordinationSite Clearance
MarkingEarthwork - masonrystone masonryBond in masonry - concrete hollow block
masonryflooringdamp proof coursesconstruction jointsmovement and expansion joints
pre cast pavementsBuilding foundationsbasementstemporary shedcentering and
shutteringslip formsscaffoldingsde-shuttering formsFabrication and erection of steel
trussesframesbraced domeslaying brickweather and water proofroof finishes
acoustic and fire protection.
UNIT III SUB STRUCTURE CONSTRUCTION 13
Techniques of Box jackingPipe Jacking -under water construction of diaphragm walls and
basement-Tunneling techniquesPiling techniques - well and caisson - sinking cofferdam -
cable
anchoring and grouting-driving diaphragm walls, sheet piles - shoring for deep cutting - well
points -Dewatering and stand by Plant equipment for underground open excavation.
UNIT IV SUPER STRUCTURE CONSTRUCTION 12
Launching girders, bridge decks, off shore platformsspecial forms for shells - techniques for
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heavy decksin-situ pre-stressing in high rise structures, Material handling - erecting light
weight
components on tall structures - Support structure for heavy Equipment and conveyors -Erection
of articulated structures, braced domes and space decks.
UNIT V CONSTRUCTION EQUIPMENT 10
Selection of equipment for earth work - earth moving operations - types of earthwork equipment
-
tractors, motor graders, scrapers, front end waders, earth moversEquipment for foundation and
pile driving. Equipment for compaction, batching and mixing and concreting - Equipment for
material handling and erection of structures - Equipment for dredging, trenching, tunneling,
TOTAL: 60 PERIODS
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UNIT I CONCRETE TECHNOLOGY
TYPES OF CEMENT
OPC33,OPC43 and OPC53 grade
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cemnt
CHEMICAL ADMIXTURES OF CONCRETE
Water-reducing admixture / Plasticizers:
These admixtures are used for following purposes:
1. To achieve a higher strength by decreasing the water cement ratio at the same workability as
an admixture free mix.
2. To achieve the same workability by decreasing the cement content so as to reduce the heat of
hydration in mass concrete.
3. To increase the workability so as to ease placing in accessible locations
4. Water reduction more than 5% but less than 12%
Actions involved:
1. Dispersion:
Surface active agents alter the physic chemical forces at the interface. They are adsorbed on the
cement particles, giving them a negative charge which leads to repulsion between the particles.
Electrostatic forces are developed causing disintegration and the free water become available for
workability.
2. Lubrication:
As these agents are organic by nature, thus they lubricate the mix reducing the friction and
increasing the workability.
3. Retardation:
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A thin layer is formed over the cement particles protecting them from hydration and increasing
the setting time. Most normal plasticizers give some retardation, 3090 minutes
Super Plasticizers:
high range water reducer
The commonly used Super Plasticizers are as follows:
Sulphonated melamine formaldehyde condensates (SMF)
Give 1625%+ water reduction. SMF gives little or no retardation, which makes them
very effective at low temperatures or where early strength is most critical.
However, at higher temperatures, they lose workability relatively quickly. SMF generally
give a good finish and are colorless, giving no staining in white concrete.
They are therefore often used where appearance is important.
Sulphonated naphthalene formaldehyde condensates (SNF)
Typically give 1625%+ water reduction. They tend to increase the entrapment of larger,
unstable air bubbles. This can improve cohesion but may lead to more surface defects.
Retardation is more than with SMF but will still not normally exceed 90 minutes. SNF is
a very cost-effective.
Polycarboxylate ether super plasticizers (PCE)
Typically give 2035%+ water reduction. They are relatively expensive per liter but are
very powerful so a lower dose (or more dilute solution) is normally used.
In general the dosage levels are usually higher than with conventional water reducers, and
the possible undesirable side effects are reduced because they do not markedly lower the
surface tension of the water.
Accelerators:
An admixture which, when added to concrete, mortar, or grout, increases the rate of hydration of
hydraulic cement, shortens the time of set in concrete, or increases the rate of hardening or
strength development.
Accelerating admixtures can be divided into groups based on their performance and application:
1. Set Accelerating Admixtures,
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Reduce the time for the mix to change from the plastic to the hardened state.
Set accelerators have relatively limited use, mainly to produce an early set.
2. Hardening Accelerators,
Which increase the strength at 24 hours by at least 120% at 20C and at 5C by at least 130% at
48 hours. Hardening accelerators find use where early stripping of shuttering or very early access
to pavements is required. They are often used in combination with a high range water reducer,
especially in cold conditions.
.
Set Retarders:
The function of retarder is to delay or extend the setting time of cement paste in concrete.
These are helpful for concrete that has to be transported to long distance, and helpful in
placing the concrete at high temperatures.
When water is first added to cement there is a rapid initial hydration reaction, after which
there is little formation of further hydrates for typically 23 hours.
The exact time depends mainly on the cement type and the temperature. This is called the
dormant period when the concrete is plastic and can be placed.
At the end of the dormant period, the hydration rate increases and a lot of calcium silicatehydrate and calcium hydroxide is formed relatively quickly. This corresponds to the
setting time of the concrete.
Retarding admixtures delay the end of the dormant period and the start of setting and
hardening. This is useful when used with plasticizers to give workability retention. Used
on their own, retarders allow later vibration of the concrete to prevent the formation of
cold joints between layers of concrete placed with a significant delay between them.
The mechanism of set retards is based on absorption. The large admixture anions and
molecules are absorbed on the surface of cement particles, which hinders further
reactions between cement and water i.e. retards setting.
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Air Entrained Admixtures:
An addition for hydraulic cement or an admixture for concrete or mortar which causes
air, usually in small quantity, to be incorporated in the form of minute bubbles in the
concrete or mortar during mixing, usually to increase its workability and frost
resistance.
Air-entraining admixtures are surfactants that change the surface tension of the water.
Traditionally, they were based on fatty acid salts or vinsol resin but these have largely
been replaced by synthetic surfactants or blends of surfactants to give improved stability
and void characteristics to the entrained air.
Air entrainment is used to produce a number of effects in both the plastic and the hardened
concrete. These include:
Resistance to freezethaw action in the hardened concrete.
Increased cohesion, reducing the tendency to bleed and segregation in the plastic concrete.
Compaction of low workability mixes including semi-dry concrete.
Stability of extruded concrete.
MANUFACTURING OF CEMENT
Raw materials used
Calcareous materials used are
o Cement rock
o Lime stone
o Marl
o Chalk
o Marine shell
Argillaceous materials used are
o Clay
o shale
o slate
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o blast furnace slag
Process manufacturing cement
Dry process
General
Adopted when the raw materials are quite hard
The process is slow an the product is costly
Process
Lime stone and clay are ground to fine powder separately and are mixed together
Water is added to make a thick paste which contains 14% of moisture
The paste format are dried and off charged into a rotary kiln
The product obtained often calcinations in rotary kiln
The clinker I obtained as a result of incipient fusion and sintering at a temp about 1400c
to 1500 c
The clinker is cooled to preserve the meta stable compounds and there solid solutions
Dispersion of one solid with another solid which made the clinker again heated
Clinker is again cooled and grounded in tube mills where 2-3% gypsum is added
The purpose of adding gypsum is to coat the cement particle by interfering the process of
hydration of cement particles
The flow diagram of dry process
Wet process
The operations are
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Process
The crushed raw materials are fed in to a ball mill and a little water is added
The steel balls in the ball mill pulverized the raw material which form a slurry with water
The slurry is passed through storage tanks where the proportioning of compound is
adjusted to ensure desired chemical composition
The corrected slurry having moisture about 40%,is then fed into rotary kiln
Where it loses moisture and form on to lumps
These are finally burned at 1500 to 1600 c
It becomes clinker at this stage, the clinker is cooled and then grounded in tube mills
While grinding the clinker 3% gypsum I added this is stored in silos and packed
Concrete Mix Design concept
Definition:
Mix design can be defined as the process of selecting suitable ingredients of concrete and
determining their relative proportions with the object of producing concrete of certain
minimum strength and durability as economically as possible.
One of the ultimate aims of studying the various properties of the materials of concrete,
plastic concrete and hardened concrete is to enable a concrete technologist to design a
concrete mix for a particular strength and durability.
The design of concrete mix is not a simple task on account of the widely varying
properties of the constituent materials, the conditions that prevail at the site of work, in
particular the exposure condition, and the conditions that are demanded for a particular
work for which the mix is designed.
Design of concrete mix requires complete knowledge of the various properties of these
constituent materials, these make the task of mix design more complex and difficult.
Design of concrete mix needs not only the knowledge of material properties and
properties of concrete in plastic condition; it also needs wider knowledge and experienceof concreting.
Even then the proportion of the materials of concrete found out at the laboratory requires
modification and re adjustments to suit the field conditions.
With better understanding of the properties, the concrete is becoming more and more an
exact material than in the past.
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The structural designer specifies certain minimum strength; and the concrete technologist
designs the concrete mix with the knowledge of the materials, site exposure conditions
and standard of supervision available at the site of work to achieve this minimum strength
and durability.
Further, the site engineer is required to make the concrete at site, closely following the
parameters suggested by the mix designer to achieve the minimum strength specified by
the structural engineer.
In some cases the site engineer may be required to slightly modify the mix proportions
given by the mix designer.
He also makes cubes or cylinders sufficient in numbers and tests them to confirm the
achievements with respect to the minimum specified strength. Mix designer, earlier, may
have made trial cubes with representative materials to arrive at the value of standard
deviation or coefficient of variation to be used in the mix design.
American Concrete Institute Method of Mix Design 11.3 (ACI Concrete Mix Design)
This method of proportioning was first published in 1944 by ACI committee 613. In 1954 the
method was revised to include, among other modifications, the use of entrained air. In 1970, the
method of ACI mix design became the responsibility of ACI committee 211. We shall now deal
with the latest ACI Committee 211.1 method.
It has the advantages of simplicity in that it:1. Applies equally well
2. With more or less identical procedure to rounded or angular aggregate
3. To regular or light weight aggregates
4. To air entrained or non-air-entrained concretes.
Manufacturing of concrete
Introduction
Production of concrete requires meticulous care at every stage
The ingredients of good and bad concrete are same but good rules are not
Observed it may become bad
Manufacturing of concrete includes the following stages
1. Batching
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2. Mixing
3. Transporting
4. Placing
5. Compacting
6. Curing
7. Finishing
Batching
The measurement of materials for making concrete is known as batching.
Methods of batching
Volume batching
The required ingredients of conc. Are measured by volume basis
o Volume batching is done by various types of gauge boxes
o The gauge boxes are made with comparatively deeper with narrow surface
o Some times bottomless gauge boxes are used but it should be avoided
Volume batching is not a good practice because of the difficulties it offers to granular material.
Some of the sand in loose condition weighs much less than the same volume of dry compacted
soil.
For un important concrete or any small job concrete may be batched by volume.
Weigh batching
It is the correct method of measuring materials for concrete.
Use of weight system in batching ,facilitates accuracy flexibility and simplicity
The different types of weigh batching are there, they are used based on the different
situation.
In small works the weighing arrangement consist of two weighing buckets connected to
the levers of spring loaded dials which indicates the load,
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Mixing
Thorough mixing of materials is essential for the production of uniform concrete
The mixing should ensure that the mass becomes homogeneous uniform in color and
consistency.
Types of mixing
Hand mixing
Machine mixing
Hand mixing
It is practiced for small scale un important concrete works
Hand mixing should be done over a impervious concrete or brick floor sufficiently large
size take one bag of cement .
Spread out and measure d out fine aggregates and course aggregate in alternative layers.
Pour he cement on the top of it and mix them dry by showel, turning the mixture over and
over again until the uniformity of color is achieved.
The uniform mixture is spread out in the thickness of about 20 cm
The water is taken and sprinkled over the mixture and simultaneously turned over
The operation is continued till such time a good uniform homogeneous concrete is
obtained
Machine mixing
Mixing of concrete almost invariably carried ot by machine ,for reinforced concrete work
medium or large scale concrete works .
Machine mixing is not only efficient it is also economical when quantity of concrete to be
produced is large
Type of mixer for mixing concrete
Batch mixer
Batch mixer produce concrete batch by batch with time interval
This is used in normal concrete work
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Batch mixers are two types
Drum types are further classified into tilting ,non tilting and forced action type
The capacity of batch mixer depends on the proportion of the mix
For 1:2:4 ideal mixer 200 liters
For 1:3:6 ideal mixer 280 liters
Mixing time
Concrete mixers are generally designed to run at a speed of 15 to 20 revolutions per minute
For proper mixing it is seen that about 25to 30 revolutions are required in a well designed mixer
It is important that a mixer should not stop in between concreting operations for this requirement
concrete mixer must be kept maintained
Transporting of concrete
Concrete can be imported by variety of methods and equipments
Methods adopted for transportation of concrete
e way
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Mortar pan
This case concrete is carried out in small quantities
This method exposes greater surface area of concrete for drying conditions
This results a geat loss of water particularly in hot weather
Mortar pan must be wetted to start with and must be kept clean
Wheel barrow
Used for transporting concrete in ground level.
This method is employed for hauling concrete in longer distance in case of concrete road
construction.
If the distance is long or ground is rough it is likely that the concrete get segregated due
to vibration
To avoid this, wheel barrows are provided with pneumatic wheel.
Crane bucket and rope way
This is one of the right way for transporting concrete above the ground level
Crane can handle concrete in high rise construction project and are becoming familiar
sites in big cities
Rope way buckets of various sizes are used
Rope way method is adopted for
Concrete works in valley
Construction work of the pier in the river
For dam construction
Truck mixer and dumpers
For large concrete works particularly for concrete to be placed at ground level
These are ordinary open steel tipping lorries
Dumpers having 2-3 cubic meter capacity
Belt conveyors also can be used for
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Chutes
Provided for transporting concrete from ground to lower levelThe surface should have same
slope not flatter than 1 vertical to 2 and a1/2 horizontal
Skip and hoist
Adopted method for transporting concrete vertically for 3 to 4 floors
Mortar pan with staging and human ladder is used for transporting concrete
Transit mixer
This is the equipment for transporting concrete over a big distance particularky ready mix
concrete
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They are truck mounted having a capacity of 4 to 7 m3
The speed of rotation of truck mixer is 4to16 rev/min
A small concrete pump is also mounted on the truck carrying transit mixer
Pumps and pipe lines
Universally accepted method
Starts with the suction stroke for suck the concrete inside the pipe
It has a piston which moves forward and backward to have suction and delivery of concrete
Placing of concrete
Concrete must be placed in a systematic manner to yield optimum results
Some situation where we used provide concrete
Placing concrete within earth mould
Placing concrete with large earth mould or timber plank form work
Placing concrete in layers with in timber or steel shutter
Placing concrete with in usual form work
Placing concrete under water
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Placing concrete within earth mould
Concrete is invariably as foundation bed below the walls and columns
Before placing concrete
All loose earth must be removed
Roots of trees must be cut
If surface is dry must be made just damp
If it is too wet or rain soaked the water slush must be removed
Placing concrete with large earth mould or timber plank form work
For construction of road slabs,air field slabs and ground floor slabs in building conc os placed in
this method
The ground surface must be free from loose earth pool of water ,grass or roots or leaves
The earth must be compacted well
Poly ethylene film is used in between conc ground to avoid absorption of moisture
Concrete is laid alternative layers to give enough scope for shrinkage
Placing concrete in layers with in timber or steel shutter
This can be used in the following cases
Dam construction
Construction of concrete abutments
Raft for a high rise building
The thickness of layers depend on
Method of compaction
Size of vibrator
Frequency of vibrator used
It is good for laying 15 to 30 cm thick layer of concrete ,for mass concrete it may varie from 35
to 45 cm
Its better to leave the top of the layer rough so that succeeding layer can have the good bond
Placing concrete with in usual form work
This can be adopt for Column ,beam and floors
Rules that should be followed while placing the concrete
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The concrete must be placed very care fully a small quantity at a time so that they will not block
the entry of subsequent concrete
Placing concrete under water
Concrete is often required to be placed under water or I a trench filled with slurry
In such a cases use of bottom slurry buckets or termic pipes are used
In the bottom bucket concrete is taken through water in a water tight box or bucket
reaching final place of deposition
The bottom is made to open by some mechanism and the whole concrete is dumped
slowly.
Compaction of concrete
Compaction of concrete is the process adopted for expelling the entrapped air from the concrete
Method for compacting concrete
Hand compaction
Compaction by vibrator
Compaction by pressure and jolting
Compaction by spinning
Hand compaction
Adopted in case of unimportant concrete
This can be adopted when mechanical mean cannot be used
It consist of
Roding
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Poking the concrete with about 2m long 16 mm dia rod to poke the concrete reinforcement
Ramming
Should be done with care
Permitted in unreinforced foundation concrete in ground floor construction
Tamping
The thickness of conc should be comparatively less
Consist of beating the op surface by wooden cross beam
The section of wooden beam is about 10x10 cm
Compaction by vibrators
We can place the concrete economically when compared to hand compaction
The use of vibrators may be essential for the production of good concrete
Type of vibrators
Internal vibrator
Formwork vibrator
Table vibrator
Platform vibrator
Surface vibrator
Vibratory rollers
Compaction by pressure and jolting
This is one of the effective method of compacting dry concrete
Often used for compacting hollow block ,cavity blocks concrete blocks
The stiff concrete is vibrated pressed and also given jolts
With the combined action of the three the stiff conc gets compacted to an dense form to
give good strength and volume
Compaction by spinning
This is one of the recent method of the compacting concrete This is adopted for fabrication of concrete pipes
The plastic concrete when at every high speed get well compacted by centrifugal force
Potential products such as spun pipes are compacted by spinning process
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Vibratory rollers
One of the recent methods of compacting very lean or dry concrete
The concrete compacted by rollers can be called as roller concrete
Tests on concrete
Concrete Slump Test
This test is performed to check the consistency of freshly made concrete.
The slump test is done to make sure a concrete mix is workable.
The measured slump must be within a set range, or tolerance, from the target slump.
Workability of concrete is mainly affected by consistency i.e. wetter mixes will be more
workable than drier mixes, but concrete of the same consistency may vary in workability.
It can also be defined as the relative plasticity of freshly mixed concrete as indicative of
its workability.
Tools and apparatus used for slump test (equipment):
1. Standard slump cone (100 mm top diameter x 200 mm bottom diameter x 300 mm high)
2. Small scoop
3. Bullet-nosed rod (600 mm long x 16 mm diameter)
4. Rule
5. Slump plate (500 mm x 500 mm)
Procedure of slump test for concrete:
clean, firm, level and non-absorbent. Collect a sample of concrete to perform the slum test
.
e with the sample. Compact
the concrete by 'rodding' 25 times. Rodding means to push a steel rod in and out of the concrete
to compact it into the cylinder, or slump cone. Always rod in a definite pattern, working from
outside into the middle.
to 2/3 and again rod 25 times, just into the top of the first layer.
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cone till it overflows.
ion. Clean any concrete from around
the base and top of the cone, push down on the handles and step off the footpieces.
Turn the cone upside down and place the rod across the up-turned cone.
Take several measurements and report the average distance to the top of the sample.If the sample
fails by being outside the tolerance (ie the slump is too high or too low), another must be taken.
If this also fails the remainder of the batch should be rejected.
Compression Test
The compression test shows the compressive strength of hardened concrete.
The compression test shows the best possible strength concrete can reach in perfect
conditions.
The compression test measures concrete strength in the hardened state. Testing should
always be done carefully. Wrong test results can be costly.
The testing is done in a laboratory off-site. The only work done on-site is to make a
concrete cylinder for the compression test. The strength is measured in Megapascals (MPa) and is commonly specified as a
characteristic strength of concrete measured at 28 days after mixing.
The compressive strength is a measure of the concretes ability to resist loads which tend
to crush it.
Apparatus for compression test
Cylinders (100 mm diameter x 200 mm high or 150 mm diameter x 300 mm high) (The small
cylinders are normally used for most testing due to their lighter weight)
1. Small scoop
2. Bullet-nosed rod (600 mm x 16 mm)
3. Steel float
4. Steel plate
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Procedure for compression test of concrete
and firm surface, ie the steel plate. Collect a sample.
ld with concrete then compact by rodding 25 times. Cylinders
may also be compacted by vibrating using a vibrating table.
mould till overflowing.
f the top with the steel float and clean any concrete from around the mould.
red and crushed
to test compressive strength
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UNIT II CONSTRUCTION PRACTICES
Sequence of activities and construction co-ordination
Planning
Planning is considered as a precondition measures before attending any development program
Particularly planning is more important in the following area
When the fund available are limited
The total requirement is much higher
Sequence of operation
It is always desirable to divide large projects into several construction stages
For prepare progress of construction each stage may be constructed under separate
contraction
It should be carried out in the proper method and arrangement
Before starting to construct the structure we must go for the sequence of operation in the
project it is better way o arrange the labour material and equipment
Following are the sequence of operation in a highway project
Site clearance
Earth work for laying embankment
Construction of drainage works
Construction of pavement structures
Installation of light poles and road signals
MARKING, SETTING OUT OF FOUNDATION
Setting out is the process of laying down the excavation lines and centre lines on the
ground before excavation is started after the foundation design is done
For setting out the foundation of a small building the centre line of the longest outer wall
of the building is first marked on the ground by stretching a string between wooden or
mild steel pegs driven at the ends Two pegs one on either from the central peg are driven at the each end of the line
Each peg is equidistant from the central peg and the distance between the outer pegs
corresponds to the width of foundation trench to be excavated
Each peg may be projected about 25 to 50 mm above ground level may be driven at a
distance of 2m from the edge of excavation
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When the string is stretched joining the corresponding pegs at the two extremities of the
line the boundary of the trench to be excavated can be marked on the ground with dry
lime powders
A right angle can be set out b forming 3, 4 and 5 units long
The centre line of the other wall which is perpendicular to the long wall can be marked
by setting out right angles
All the specifications are made by tape or prismatic compass may be used for setting out
right angles
Similarly outer lines of the foundation trench of each cross wall can be set out
For big project reference pillars of masonry is constructed first, these pillars may be
about 20cm thick and 15cm wider than the width of the foundation
EXCAVATION
Excavation of foundation can be done by manually or with the help of special mechanical
equipments
Manually it can be done by the help of following equipments
o Spade
o Phawrah
o Pick axe
o Crowbar
o Rammer
o Wedge
o Boning rod
o Sledge hammer
o Basket
o Iron pan
o line and pins
Mechanically the excavation can be done by the help of following machineries
o Boom bucket dipper handle
o Trench
o Chain mounted buckets
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o Raking cut
o Vertical cut
FOUNDATION
The foundation is he lower portion of the building, usually located below the ground level, which
transmit the load of super structure to sub soil
Functions of foundation
Types of foundation
Shallow foundation
If the depth of foundation is less than or equal to width of foundation it is called as shallow
foundation
Types of shallow foundation
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Trapezoidal footing
If the independent footings of two columns are connected by a beam it is called as strap footing
A strap footing may be used where the distance between the columns is so great that a combined
trapezoidal footing becomes quite narrow
The strap beam does not remains in contact with soil and thus does not transfer any pressure to
the soil
Mat foundation
A raft or mat is a combined footing that covers the entire beneath a structure
And supports all walls and columns
It is used when the allowable soil pressure is low are the building loads are heavy
It is used to reduce the settlement above highly compressible soil
Rafts may divided into three types
o Solid slab system
o Beam slab system
o Cellular system
Deep foundation
If the depth of foundation is equal to or more than the width of the foundation is called deep
foundation
Types
Deep strip footing
Whenever the depth of strip footing is more than the width it is called as deep strip footing
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Pile foundation
it is a type of deep foundation in which the loads are taken to a low level by means of vertical
members which may be timber or concrete or steel
Types of pile foundation
ng and friction pile
End bearing piles
End bearing piles are used to transfer load through water or soft soil to a suitable bearing stratum
Such piles are used to carry heavy loads to hard strata
Multi storied buildings are invariably founded on end bearing piles, so that the settlements are
minimized
Friction pilesFriction piles are used to transfer loads to a depth of a friction load carrying material by means of
skin friction along the length of the pile
These piles mostly used in granular soil
Combined end bearing and friction pile
These are the piles which transfer the super imposed load both through side friction as well as
end bearing
Such piles are more common, especially the end bearing piles are passed through granular soil
Compaction piles
These piles are used o compact loose soil thus increasing there bearing capacity
The pile tube driven to compact the soil is gradually taken out and sand is filled in its place thus
forming the sand pile
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Pier foundation
A pier foundation consist of a cylindrical column of large diameter to support transfer large
super imposed loads to the firm strata below
Generally pier foundation is shallower in depth than the pile foundation
It has two types
o Masonry
o concrete pier
Drilled caissons
Well foundation or caissons are box like structurescircular or rectangular which are
sunk from the surface of either land or water to the desired depth
Caisson foundations are used for major foundation work such as
Bridge pier and abutments in river
Wharves and quay walls docks
Large water front structures such as pump houses, subjected to heavy vertical and
horizontal loads
Well foundations are caissons are hollow from inside, which may filled withstand and are
plugged at the bottom, the load is transferred to the perimeter wall called as steining
Stone Masonry
Definition:
The art of building a structure in stone with any suitable masonry is called stone masonry.
Types of Stone Masonry:
Stone masonry may be broadly classified into the following two types:
1. Rubble Masonry
2. Ashlar Masonry
1. Rubble Masonry:
The stone masonry in which either undressed or roughly dressed stone are laid in a suitable
mortar is called rubble masonry. In this masonry the joints are not of uniform thickness.
Rubble masonry is further sub-divided into the following three types:
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1. Random rubble masonry: The rubble masonry in which either undressed or hammer dressed
stones are used is called random rubble masonry. Further random rubble masonry is also divided
into the following three types:
a. Un coursed random rubble masonry: The random rubble masonry in which stones are laid
without forming courses is known as un coursed random rubble masonry. This is the roughest
and cheapest type of masonry and is of varying appearance. The stones used in this masonry are
of different sizes and shapes. before lying, all projecting corners of stones are slightly knocked
off. Vertical joints are not plumbed, joints are filled and flushed. Large stones are used at corners
and at jambs to increase their strength. Once "through stone" is used for every square meter of
the face area for joining faces and backing.
Suitability: Used for construction of walls of low height in case of ordinary buildings.
b. Coursed random rubble masonry: The random rubble masonry in which stones are laid in
layers of equal height is called random rubble masonry. In this masonry, the stones are laid in
somewhat level courses. Headers of one coursed height are placed at certain intervals. The stones
are hammer dressed. Suitability: Used for construction of residential buildings, go downs,
boundary walls etc.
2. Squared rubble masonry:The rubble masonry in which the face stones are squared on all
joints and beds by hammer dressing or chisel dressing before their actual laying, is called
squared rubble masonry.
There are two types of squared rubble masonry.
a. Coursed Square rubble masonry: The square rubble masonry in which chisel dressed stones
laid in courses is called coarse square rubble masonry. This is a superior variety of rubble
masonry. It consists of stones, which are squared on all joints and laid in courses. The stones are
to be laid in courses of equal layers. and the joints should also be uniform. Suitability: Used for
construction of public buildings, hospitals, schools, markets, modern residential buildings etc
and in hilly areas where good quality of stone is easily available.
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b. Un coursed square rubble masonry: The squared rubble in masonry which hammer dressed
stones are laid without making courses is called un coursed square rubble masonry. It consists of
stones which are squared on all joints and beds by hammer dressing. All the stones to be laid are
of different sizes. Suitability: Used for construction of ordinary buildings in hilly areas where a
good variety of stones are cheaply available.
3. Dry rubble masonry: The rubble masonry in which stones are laid without using any mortar
is called dry rubble masonry or sometimes shortly as "dry stones". It is an ordinary masonry and
is recommended for constructing walls of height not more than 6m. In case the height is more,
three adjacent courses are laid in squared rubble masonry mortar at 3m intervals.
2. Ashlar masonry:
The stone masonry in which finely dressed stones are laid in cement or lime mortar is known as
ashlars masonry. In this masonry are the courses are of uniform height, all the joints are regular,
thin and have uniform thickness. This type of masonry is much costly as it requires dressing of
stones.
Suitability: This masonry is used for heavy structures, architectural buildings, high piers and
abutments of bridges.
Ashlars masonry is further sub divided into the following types:
hlar masonry
Ashlar fine or coursed ashlar masonry: In this type of stone masonry stone blocks of same
height in each course are used. Every stone is fine tooled on all sides. Thickness of mortar is
uniform through out. It is an expensive type of stone masonry as it requires heavy labor and
wastage of material while dressing. Satisfactory bond can be obtained in this type of stone
masonry.
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Random coursed ashlar masonry: This type of ashlar masonry consists of fine or coursed
ashlar but the courses are of varying thick nesses, depending upon the character of the building
Rough tooled ashlar masonry: This type of ashlar masonry the sides of the stones are rough
tooled and dressed with chisels. Thickness of joints is uniform, which does not exceed 6mm.
Rock or quarry faced ashlar masonry: This type of ashlar masonry is similar to rough
tooled type except that there is chisel-drafted margin left rough on the face which is known as
quarry faced.
Chamfered ashlar masonry: It is similar to quarry faced except that the edges are beveled or
chamfered to 450 for depth of 2.5 cm or more.
-in course masonry: It is the name given to a class of ashlar masonry which occupies an
intermediate place between rubble and ashlars. The stones are all squared and properly dressed.
It resembles to coursed rubble masonry or rough tooled ashlar masonry.
Ashlar facing: Ashlar facing is the best type of ashlars masonry. Since this is type of masonry
is very expensive, it is not commonly used throughout the whole thickness of the wall, except in
works of great importance and strength. For economy the facing are built in ashlars and the rest
in rubble.
Brick masonry
cher bricks on edges instead of bed
This bond is weak in strength but it is economical Brick masonry is made up of brick units
bonded together with mortar
Components of brick masonry
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Types of mortar
-lime mortar
Types of bricks
Traditional bricks
It has not been standardize in size
Dimensions varies from place to place
Thickness varies from varies from cm to 7.5cm,widthvaries from 10to13 cm and length varies
from 20to25 cm
Modular brick
Any brick which is the same uniform size as laid down by bis
The nominal size of the modular brick is 20cm x10cmx10cm
Actual size is 19x9x9
Classes of brick
Bonds in brick work
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Single Flemish bond
Single Flemish bond is comprised of double Flemish bond facing an English bond backing and
hearting in each course
Facing bond
This bond is used where the bricks of different thickness are to be used in the facing and backing
of the wall
The nominal thickness of facing brick is 10 cm and that of backing bricks is 9 cm the header
course tis provided at a vertical interval of 90 cm
English cross bond
This is he modification of English bond to improve the appearance e of the wall
Brick on edge bond
This type of bond uses stret
dutch bond
DAMP PRPOOF COURSE
Introduction
One of the basic requirements of the building is that it should remain dry or free from moisture
traveling through walls, roofs and doors
Dampness is the presence of hydroscopic or gravitational moisture in the building
Dampness gives rise of un hygienic condition, and reduction of strength of structural components
Every building should be damp proof
Causes of dampness
Moisture rising up from the ground to the walls
Moisture constantly travels through the substructure. in impervious soil lot of soil moisture
present in the soil this moisture may rise up in the wall and floor trough capillary action
Ground water rise will also result in moisture entry into the building through walls and floors
Rain travel from wall tops
If the walls are not properly protected from rain penetration, rain will enter into the wall and
travel down
Leaking roofs will also permit the water to enter in the wall
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Rain beating against external walls
Heavy showers of rain may beat against external walls
If the balconies do not have proper outward slope water will enter in the building interior and it
would completely deface the decoration of the wall
Condensation
Due to condensation of atmospheric moisture water is deposited on the
Walls, floors and ceilings
Methods of damp proofing
Membrane damp proofing
Introducing a water repellent membrane or damp proof course between the source of dampness
and the part of the building adjacent to it .
Dpc may be consist of flexible materials such as bitumen, mastic asphalt, bituminous felts,
plastic are polythene metal sheets .
Integral damp proofing
This consist of adding certain water proofing compounds of materials to the
concrete mix so that it becomes impermeable
These water proofing compounds made from
Chalk, talk and fullers earth
Compounds like alkaline silicates, aluminum sulphate, and calcium chloride
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Surface teatement
This consist of application of layer of water repellentsubstance or compounds on the
surface through which moisture enters
The use of metallic soap such as calcium and aluminium oletes and stearates are much
effective against rain water penetration
Surface treatment is effective only the moisture is superficial and its not under pressure
Cavity wall construction
this is an effective method of damp prevention in which the external wall of the building
is shielded by an outer skin wall leaving a cavity between the two guniting
This consist of depositing under pressure ,an impervious layer of rich cement mortar over
the exposed for water proofing or over pipes for resisting the water pressure
Cement mortar consist of 1:3 cement sand mix which is short on the cleaned surface with
the help of cement gun under a pressure of 3to 4 kg/cm2
Pressure grouting
This is the process of forcing cement grout under pressure, into cracks, voids, fissures etc
present into the structural components
This method is quite effective in checking the seepage of raised ground water
Materials used for damp proofing course
Hot bitumen
Mastic asphalt
Bituminous or asphaltic felts
Metal sheets
Combination of sheets and bituminous felts
Bricks
Stones
Mortar
Cement concrete
Plastic sheets
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FLOORS
The purpose of floor is to provide a level surface capable of supporting the occupants of the
building, furniture, equipment and some time interior wall
The floor must satisfy the following requirements
resistance
Components of a floor
Sub floor, basecourse or floor base
Floor covering or flooring
Selection of flooring materials
Factor that affect the choice of flooring
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Types of flooring
ng cement concrete flooring
Mud flooring and muram flooring
This type of flooring is cheap, hard highly impervious
It is easy to construct and easy to maintain
It has good thermal insulation property due to which it remains cool in summer and warm in
winter
Over a well prepared ground 25 cm thick selected moist earth is spread and it rammed well to
compacted thickness of 15cm
In order to prevent cracks small quantity of chopped straw is mixed
Muram flooring
Muram is a form of disintegrated rock with binding material
To construct such a floor a 15 cm thick layer muram is laid over prepared sub grade over it 2.5
cm thick powder layer of muram is spread and rammed
Brick flooring
The sub grade is compacted properly, to the desired leveland 7.5 cm thick layer is spread
Over this a course of brick is laid flat in mortar is built
Such flooring is used in cheap construction, especially where good bricks are available
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Tiled flooring
Tiledflooring is constructed from square ,hexagonal or other shapes made up of clay
cement concrete and terrazzo
These are available In various thickness
Thes are commonly used in residential houses ,schools,hospitals and other public
buildings
Over the concrete base a 25 to 30 mm thick layr of lime mortar 1:3 to serve as a bedding
The bedding mortar is allowed to harden for 12 to 24 hours
Neat cement slurry is spread over it and the tiles are laid flat over it
Marble flooring
It is the superior type of flooring used in bathrooms and kitchens of residential building
and hospitals ,sanitorium ,temples etc
After the preparation of base concrete 20 mm thick bed layer of 1:4 cement mix spread
under the area of each individual slabs.
The marble layer is then laid over it and pressed with wooden mallet and leveled
Timber flooring
Timber flooring is used for carpentry halls ,dancing halls auditorium
Etc
These are not commonly usedin India because its costlier
But hilly area where wood is available and temperature drops very low timber flooring is
quite common
The suspended type of wooden floor is supported above the ground
The solid type of wooden floor is fully supported on the ground
SCAFFOLDING
When te higt of wall or column or othet structural member of a building exceeding1.5 m
temporary structures needed to support trhe platforms over which the work man sit and carry o
the work
These temporary structures constructed very close to the wall is in the form of imber o steel
frame work commonly called as scaffoldings
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Components of scaffoldings
or needle scaffoldings
Single scaffoldings
This consists of a single frame work of standards, legers, put logs etc
Constructed parallel to the wall at a distance of about 1.2 meters
The standards are placed at a distance of 2to2.5m interval
Ledger connected with the standards, and are provided at a vertical distance of 1.2to 1.5 m Put
logs or connected with one end on the ledgers and other end at the holes of the wall at an interval
of1.2 to 1.5 m interval
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Double are masons scaffoldings
It is very difficult to put holes in walls to m support putlogs in stone masonry
In the case a strong scaffolding is used consisting of two rows of scaffolding
The first row placed 20 to 30 cm away from the wall the other frame will 1m distance
from the first one
Put logs are the supported on both the supports, rakers and cross braces are provided to
make the scaffolding more strong
It also called as independent scaffoldings
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Cantilever or needle scaffolding
Cantilever supports can be used under following circumctances
Ground is week to support standards
Construction of the upper part of the wall is to be carried out
It is required to keep the ground near wall free for traffic etc i
It ha s two types
Single Frame
Te standards are supported on series of needle taken out through opening or through holes
Double frame
The needles are projecting beams are strutted inside the floors
Suspended scaffolding
It is the light weight scaffolding used for repair works such as pointing, painting etc
The working platforms are suspended from roofs by means of wire ropes or chains etc
Trestle scaffolding
Such type of scaffoldings are used for painting and repairing work inside the room up to a height
of 5m
The working platform is supported over the top of movable contrivances such as tripods ladders
etc
Steel scaffolding
Steel scaffolding is practically similar to the timber scaffolding, here wooden members
are replaced by steel couplets are fittings
Such scaffolding can be erected and dismantled rapidly
It has a greater strength and greater durability
Patented scaffolding
Many patented scaffolding made of steel are available in the market
Thos scaffoldings are equipped with special couplings frames etc
TRUSSES
Trusses are the frame formed by number of straight members connected in the form of
triangles
The embers are made by steel angles and they are joined by rivet or welding, these joints
are called nodes
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It is assumed that the external loads act at the nodes only and the members are subjected
to only tension or compression
The compression members are called as struts and the tension members are called as ties
Steel roof trusses are used under the following condition
Large spans are to be covered
Intermediate columns are to be avoided to have an unobstructed working area inside
There is a heavy rain or snow fall
Types of roof trusses
King post truss Here t he common rafters are supported by wooden frame work called truss under
required interval
The frame work consist of a king post, two struts two principal rafters and tie beam
The truss rest on stone bed blocks at either end
The common rafters rest on wooden purlins which in turn are fixed to the principal rafters
of the truss
The king post connect the ridge post and the middle of the tie beam
The struts are connected to the king post at the bottom and the principal rafters at the top
The roofing material is fixed to the common rafters king post truss is used for spans of
5m to 9m
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Queen post truss
The frame work consist of two principal rafters ,two queen post one straining sill two
struts one tie beam and one straining beam
The common matters rest on wooden purlins
The staining beam resist the horizontal thrust developed
The struts are connected to the queen post at the bottom and the principal rafters at the
top
North light roof truss
North light or saw tooth roof truss is special type of roof trusses suitable for factories
engaging in manufacturing work North light truss is sawtooth
Actual lighting is taken an advantage during day time by using the north light roof trusses
In this type of trusses vertical drops are provided this drops are covered with glasses so as
to permit light in to the interior
Centering and shuttering
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Shuttering is the temporary ancillary construction used as a mould for the structures
In which the concrete is placed and allowed to hardened
These are classified as steel wooden plywood combined woods steel, reinforced concrete
and plain concrete
Requirements of shuttering
The material should be cheap and should be suitable for re use several times
It should be practically water proof so that it should not observe water from concrete
It should be strong enough to with stand all loads coming on it
It should be stiff enough so that deflection is minimum
The surface of the formwork should smooth and it should afford easy stripping
Loads on form work
Live load due to labour etc
Dead weight of wet concrete
Hydrostatic pressure of the fluid concrete
Impact due t pouring concrete
Shuttering for column
Components
Sheeting or column shutter all around the column
Yokes
Wedges
bolt
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Shuttering for beam and slab floor
The slab is continous over the beam
The slab is supported on 2.5 cm thick sheeting laid parallel to the main beam
form work for stairs
Shuttering of walls
The boarding may be 4 to 5 cm thick for walls up to 3to 4m high
The boards are fixed to 5cmX10cm posts known as struts are soldiers
ROOF FINISHING Roof finishing accessories include all types of accessory materials that are used to finish
a roof. Flashing, drip edge, and roof drains are all examples of roofing accessories.
Roof finishing accessories are widely available for a range of applications and may be
chosen for functional, aesthetic, or budgetary reasons.
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Roofing accessories are largely made from aluminum, steel, copper, or PVC vinyl. They
include a range of products including
Rain gutters and Drains and guards
Flashing or weatherproofing materials
Rain gutters and Drains and guards
Rain gutters, drains and guards are roof finishing accessories that collect and divert rainwater
away from the roof and building foundation.
These types of roof finishing accessories may also reduce erosion, prevent leaks in the
foundation or basement, reduce water exposure on painted surfaces, and collect water for
additional use.
Rain gutter, drain and guard roof finishing accessories may be available with screens, louvers, orhoods for additional protection.
Flashing or weatherproofing materials
Roof finishing accessories also include flashing, also known as weatherproofing.
Flashing refers to installing a thin, continuous piece of sheet material to prevent the passage of
water into the structure from a joint or angle.
Flashing roof finishing accessories are commonly used around protruding objects in the roof,
such as chimneys or pipes, to prevent water from reaching seams or joints.
Roof caps, drip edges, ridges and shingles, and chimney caps
Roof caps, drip edges, ridges and shingles, and chimney caps are also common, functional roof
finishing accessories
. Roof caps provide ventilation via the rooftop. They are commonly made from copper or
galvanized steel, and often include an insect screen.
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Drip edge roof finishing accessories are useful in stopping water from seeping under a roof deck,
which can prevent frame rot.
Roof ridge caps and shingles are also used as finishing accessories. Roof shingles are individual,
overlapping elements used for water-resistance.
At the roof ridge, there is typically a copper, lead, or plastic cap to ensure water protection.
Ridge vents are also commonly used as roof finishing accessories to provide ventilation to attic
or upper crawlspaces.
Leader boxes, Finials and turrets and Weathervanes.
Finishing accessories can also be decorative.
These accessories include leader boxes, finials and turrets, and weathervanes. Leader box
accessories are used with gutter systems to hide or diminish the sight of leader elbows, and are
available in a range of decorative styles, shapes, and designs.
Roof finials and turrets are caps or towers affixed to the highest point of the roof, largely for
decoration. Turrets are often designed to hold clocks or bells.
Similarly, weathervanes are another type of roof finishing accessory often used for decoration at
the highest point of the roof. Weathervanes are not solely used for decoration, however, as they
also point to the direction of the wind. Other, unlisted types of roof finishing accessories may
also be available.
ACOUSTICSAcoustics is the science of sound ,which deals with origin ,propagation and auditory sensation of
sound and also with design and construction of different building units to set optimum condition
for producing and listenig speech musi etc
FIRE PROTECION
No building material is perfectly fire proof
A wider interpretation of the fire safety may be deemed to cover the following aspects
Fire prevention and reduction of number of out breaks of fire
Spread of fire both internally and externally
Safe existence of any and all occupants in the event of an out breaks of fire
Fire load
Fire load is the amount of heat in kilocalories which is liberated per square meter of floor area of
any combustible parts of the building itself
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The fire load is determined by multiplying the weight of all combustible materials by their
calorific value and dividing the floor area under consideration
Grading of building according to fire resistance
The national building code of India (sp:7-1970) divides building in to the following four types
according to the fire load the building is designed to resist
Type 1 construction all structural components have 4 hours fire resistance
Type 2 construction all structural components have 3 fire resistance
Type 3construction all structural components have 2 hours fire resistance
Type 4 construction all structural components have 1 hour fire resistance
General fire safety requirements for buildings
All building and particularly building having more than one storey shall be provided with
liberally designed and safe fire proof existence
The exist shall be so placed that they are always immediately accessible and each is
capable of taking all the persons on that floor a s alternative escape route
Escape route shall be well ventilated as persons using the escapes are likely to over come
from smoke Fire proof door shall conform rigidly to the fire safety requirements
Electrical and mechanical lifts while reliable undr normal condition may not always be
relied on escape purpose
Lift shafts and stairways invariably serve as flues are tunnels thus increasing the fire by
increased draught
Floors are required to withstand the effect of fire for full period stated for the particular
grading
Roofs of the various fire grades of the building shall be designed and constructed to
withstand the effect of fire for the maximum period
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UNIT III SUB STRUCTURE CONSTRUCTION 13
TECHNIQUES OF BOX JACKING
Necessity of this technique
When the increasing demands for various forms of transport infra structure to be constructed in
congested locations or below existing facilities the need to be able to install large structures
without destruction is a growing need.
The jacking of large boxes to create an underpass below a railway track or road without
destruction
For around 30 years this box jacking techniques has found wide use Europe and India
Types of structures under jacking
Box jacking
Arch jacking
Pipe jacking
OPERATIONS
The box shaped tunnel structures are pre fabricated units which are pushed into soil by
hydraulic jack
Soil is excavated at the advancing face by manual means or by excavators
To avoid settlements of over laying roads or rail track soil is excavated after it enters the
cutting heads Excavation ahead of the cutting is avoided the cutting head is moved forward in small
increments to avoid any having of the road or rail track
In addition to that, without stabilizing the soil, the box technique would cause the super
structure to settle the threatening structure failure so the ground ahead of tunnel boxes
needed to be frozen
PIPE JACKING
In tunnels of damages above 2m men and machines worked the tunnel phase exacting and
providing soil support to the excavator soil by erecting the lining. The tunnel diameter becomes
small it becomes difficult for workers to carry out soil excavation of in erect the tunnel lining
system with in the tunnel shield
For diameter in the range of 0.5m to 1.5m it is more efficient to excavate the soil by drilling
systems controlled from a shaft or a pit to push the tunnel lining segment from the shaft or pit
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these techniques are often referred to us pipe jacking or micro tunneling techniques and
equipments
Pipe jacking refers to a technique in which a man in a sitting or crouch position, users epic and
shovels to excavate tunnel face and the pipe is jacked forward from a shaft using hydraulic
jacking system
Horizontal auguring refers to a similar technique in which the man is replaced by a horizontal
continuous flight helical auger
INSTALLATION
The pipe sections are moved forward by hydraulic jacking and the miniature TBM derive its
reaction from these section
Pipe segments of length 1 to 3 diameters 0.5 to 2m can be jacked into the soil using reaction
from the concrete wall erected at the rior of jacking pit.
DIAPHRAGM WALL
In structural engineering, a diaphragm is a structural system used to transfer lateral loads
to shear walls or frames primarily through in-plane shear stress
. These lateral loads are usually wind and earthquake loads, but other lateral loads such as
lateral earth pressure or hydrostatic pressure can also be resisted by diaphragm action.
The diaphragm of a structure often does double duty as the floor system or roof system in
a building or the deck of abridge, which simultaneously supports gravity loads. Diaphragms are usually constructed of plywood or oriented stand board in timber
construction;
Metal deck or composite metal deck in steel construction; or concrete slab in concrete
construction.
The two primary types of diaphragm are flexible and rigid. Flexible diaphragms resist
lateral forces depending on the tributary area, irrespective of the flexibility of the
members that they are transferring force to
. On the other hand, rigid diaphragms transfer load to frames or shear walls depending on
their flexibility and their location in the structure.
Parts of a diaphragm include:
-plane shear
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s
since the membrane is usually incapable of handling these loads alone.
TUNNELING
Process of making tunnels in order to reduce distance of travel or traffic congestion for highway
and railway is called tunneling
Tunneling is important for the following purpose
o Time saving and reduction in fuel
o Avoid unwanted traffic congestion
o Maintain a proper speed
o Avoid tiredness of travel
o Avoid unwanted accidents
o To avoid deforestation and death of animal while crossing
o To avoid land slide in hilly region
o To avoid the long route around the mountain
o To reduce the length of highway and railway and it may be economical
o To have flatter gradient that is essential to maintain the speed of the vehicle
Tunneling types depending upon the shapes
Poly centric
Horse shoe
Size of the tunnel
It depends upon the number of track and the width and length of the mountain
Alignment of tunneling
o Identify the shortest route
o Height of mountain should be less
o Mark the points on the mountain
o Transfer the tunnel inside the mountain by making of required depth
o Checking the tunnel cross section whether equal every where
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Methods of tunneling
Shaft tunneling
Pilot tunneling
Shaft tunnels
Vertical passages are created along the line o the tunnel then the tunnels can be excavated by the
passage of having distance half of the distance between adjacent passage openings are available
to take the excavated material ,shafts can also be used to pump out the water
Pilot tunneling
If the height of the mountain is more then we can exercise this method of tunneling but uf he
horizontal length is more, shaft tunneling is done
PILE DRIVING
This is the process of inserting the pile inside the soil
It is a process by way of which a pile is forced in to the ground with out excavating the soil
Pile driving can be done by two methods
Using hammering
Using pile driver
Hammering
Heavy bl0w is given by means of a hammer
Variety of hammers available to perform some of the acion
hammer
Drop hammer
The hammer is lifted by a winch and dropped down
The hammer is connected to the rope by a hook
When it is lifted up after reaching a particular height it is dropped down
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Single acting hammer
Hammer is lifted by stream and dropped then it will fell down in the top of the pile by
gravitational force
Double acting hammer
It is the same as that of single acting but here both the lifting and dropping is done by steam
engine
Diesel hammer
The process of lifting and dropping is done by diesel engine
Vibrators
If the soil condition is loose ,then using some vibrators the pile is inserted
SHEET PILES
It is the type of pile that is made of concrete, steel or wood
The thickness of the pile is very less when compared to the length and width of the pile
To prevent the entry water in construction the sheet piles are used, this is also used to
separate the vertical member of the building
The piles are inserted by some machine the depth of the piles can be increased by proper
joints in successive installment
Functions
To enclose the site or part to prevent escape of loose soil
To retain the sides of trenches or excavation
To construct retaining wall in the marine structures
To prevent seepage below the dams or hydraulic structures to construct coastal defense
work
To protect the foundation from scouring action of nearby river
Concrete sheet piles
Reinforced precast unit having the width of 50 to 60 cm and thickness 2to 6cm and the depth can
be increased by further installment
Timber sheet piles
it is used only for temporary works ,the width of the pile varies from 225to 280 cm the thickness
shall not be less than 50mm
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DEWATERING
DEFINITION
When water table exists at a shallow depth below ground surface, it is essential to lower the
water so as to carry out construction of foundation, basement, and metro tunnels etc.This is
achieved by pumping out water from multiple wells installed at the site. The process is called as
dewatering.
Types of dewatering method
Dewatering can be done by adopting one of the following four strategies
Dewatering of soil by temporary lowering of water table using wells and pumps prior
excavation as depleted in figure
Allowing water to reap into excavation area, collecting it in sumps and pumping it out.
Before that adequate steps have to be taken to support the soil on sides of the excavated
area, to prevent washing away of fines and have sufficient space for the work area.
Making the soil around excavated zone impermeable by technique such as grouting are
freezing so that inflow of water is stop are minimized.
INSTALATION TECHNIQUE
Sufficient size and capacity of dewatering system is necessary to lower and maintain
ground water table and to allow material to be excavated in a reasonable dry condition.
Excavation slopes to be stabilized where sheeting is not required
Dewatering system is to be operated continuously until backfill work has been
completed.
Then, the structure to be constructed at the excavated area has to be finished
The complete stand by have to be available for immediate operation as may be required,
to adequately maintain dewatering on continuous basis and in the event that all or any
other part of the system may become inadequate or fail
The water removed from the excavation to be disposed in such a manner as will notendanger portions of work under construction or completed.
For dewatering purpose, well points deep well, caissons and tunnels are used.
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WELL POINTS
DEWATERING
When construction operation have to be excited below the ground water table level. Dewatering
of soil can be done by the following methods
Collecting water in sumps and pumping it out.
Installing well points small or deep wells and pumping out ground water
Using special technique in fine grained soils such as vaccum dewatering and electro-osmosis
WELL POINTS
To pump out the ground water small sized wells called well points are used for a more dry
working area the two methods used most often for lowering water table below the excavation
level are the well point method and the deep well method.
WELL POINT METHOD :
This is economical and useful for lowering the water table by 15m or less.
Incase of well point method or deep well method it is based on the fact that removal of
water by continuous pumping from a well causes the water table level to become
depressed and result in the formation of draw down.
When a series of wells are placed close to each other, the overall effect is lowering of the
water table level. Well points, being smaller, are easy to install.
Well points, can lower the water table by only 6.7m because the pump, is located at the
ground surface and connected to group of well points through a pipe, cannot lift water
from greater depth.
Beyond 7m, multistage well points are used.
DEEP WELL METHOD
This method is useful for lowering the water table by more than 15m.
Deep wells have larger diameter more depth and greater spacing.
The pump is located at the bottom of well and hence can pump out water from greater depth.
Deep wells become more economical if more points are required.
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UNIT IV SUPER STRUCTURE CONSTRUCTION
BRIDGE DECKS
The principal function of a bridge deck is to provide support to local vertical loads (from
highway traffic, railway or pedestrians) and transmit these loads to the primary superstructure of
the bridge, Figure 1(1). As a result of its function, the deck will be continuous along the bridge
span and (apart from some railway bridges) continuous across the span. As a result of this
continuity, it will act as a plate (isotropic or orthotropic depending on construction) to support
local patch loads.
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Continuity ensures that whether or not it has been designed to do so, it will participate in the
overall structural action of the superstructure. The overall structural actions may include:
of the longitudinal girders, Figure 1(2).
and cross girder structures, throughout the span, Figure 1(3).
longitudinal and cross girders, Figure 1(4).
It may be necessary to take account of these combined actions when verifying the design of the
deck. This is most likely to be the case when there are significant stresses from the overall
structural actions in the same direction as the maximum bending moments from local deck
actions, e.g. in structures with cross girders where the direction of maximum moment is along
the bridge.
The passage of each wheel load causes a complete cycle of local bending stresses. The number
of significant stress cycles is, therefore, very much higher for the deck than for the remainder of
the superstructure. In addition, some of the actions of the deck arising from its participation in
the overall behaviour are subject to full reversal;
an example is the transverse distribution of vertical load between girders. For both these reasons,
fatigue is more likely to govern the design of the bridge deck than the remainder of the
superstructure.
SHELL STRUCTURES
Shells are 3d structures constructed on storage tanks or roof for large column area such as indoor
stadiums, exhibition halls, theatres, complex churches etc
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Before analysis and design of foundation it is necessary to determine the soil characters
of the sea shore. Capacities of the available crains will influence the operational activities
of platform constructions.
The fixed platforms can be classified into
Jacket or template structures
Gravity structures
ERECTING LIGHT WEIGHT COMPONENTS ON TALL STRUCTURES
Besides high raise buildings the usage of steel element is also popular with construction
of hospital and commercial complexes
Instead of concrete beams and columns more than 6100 tonnes of steel have been used to
build the main frames
Light weight blocks are used for patricians to reduce the dead load building
The usage of permanent concrete form works and structural steel elements will be the
main constituter for erecting light weight components on tall structures results rapid
speed of constructions.
Hence the erection of steel beams and columns as well as the installation of concrete
form work consumes only less time
Self drilling tapping screws are the most prevalent fasteners. Steel to steel connections
can be carried out to connect struts or joist and track together
Entire can be erected manually with out the use of heavy equipment
All these structures require few battery powered screw gunes and some ropes and pulleys
No scaffoldings is require for assembly and disc assembly of the structures because the
structure itself provides the scaffoldings as it goes up or comes down
Almost any number of column sections can be added to make it any height we desire
During the construction of tall structures the following equipments areused for the aerial
transporting and handling
Aerial cable way
Helicopter
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UNIT V CONSTRUCTION EQUIPMENT
Construction equipments
Types of earth moving equipment
Classified into following types
e equipment
TRACTORS
Tractors are machine which change the engine energy into tractive energy
These are primarily used for pull or push the loads
They are also used for different purposes by mounting many types of accessories
Types of tractor
Crawler type or track type
Rubber tired or wheel typeThe tractor is multi purpose machine
Light models are used for agricultural or short haulage works
Heavy models are employed in earth moving works, cranes, shovels or special rigs
Wheeled types or employed in light but speedy jobs
Main constituents of tractor are engine ,clutch ,transmissonsystem,ground drive and
controls
Factors should be considered while selecting a tractor dozer
Size of the dozer for given job the type expected from the track to dozer
The type and condition of haul road
distance to be move
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Bulldozers
Dozers are machine designed primarily for cutting and pushing the material over short
distance
They consist with a front mounted blade controlled by hydraulic cylinder to vary the
depth of cut and rate of leveling depending on the material and application
a dozer is frame mounted unit with a blade, curved in its section, extending in front of the
tractor
Bulldozer is most versatile and most important equipment on construction project
Basically its pushing unit but its widely used as multipurpose equipment and can perform
large number of operations with minor changes
Scrapers
Scrapers are the devices to scrap the ground and load it simultaneously, transport it for the
required distance and dump it and then spread it for the required area
The scrapers are designed to dig,load,haul,dump and spread
The scrapers are of three types
Towed type
The towed type scrapers are provided with either cable or hydraulic control
It can be operated in extremely adverse condition
Conventional scrapers
These are generally manufactured from 10to 25cubicmetres
Self loading scrapers
These are twin engine scrapers
It can work completely independently of all other plants
It has the following parts
Bowl
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Cutting edge
Apron
Tail gate or ejector
Following or three major operations of scrapers
Loading or digging
Transporting
Unloading
SELECTION OF EQUIPMENT
Proper selection of construction equipment place a vital role in the speedy and
economical completion of the construction
Following are the main points which should be considered while selection off the
construction equipments
Suitable for job condition
The equipment must meet the requirement of the work climate and working condition
Size of the equipment
Size of the equipment it should be such that must be able to be used with other
equipments
If the equipment selected for larger size it will remain idle inmost of the time
Standardization
It is better to have same type and size of equipment in a construction then it is easy to
have spare parts, and to understand its operations
Availability of equipment
Availability of spare parts
Multi purpose equipments the selected equipments must be capable of performing
various operations
Availability of know how
The equipments selected should be satisfactorily handled by the available operators and
machine
Use in future projects
The economical aspects
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Static compaction equipment
It has several types
Towed static smooth compactors
Smooth rolls where the first type of rolling compaction equipment used
These where pulled by men or horses and were first used by Romans to smoothen there roads
Static sheep foot or pad foot compactors
When compacting the earth the feet penetrate deep in to th e loose material during the first passes
and compact the soil from bottom up
The kneading effect of sheep foot compactors is used to break up the
Earth lumps and reduce the air voids
Static three wheeled self propelled compactors
These have three rolls a small usually split steering role in the front
Two large drive rolls mounted on rear axle at both the end
Static tandem compactors
Tandem rolls have two equal sized rolls and are centered in line tandem
These are used for the compaction of bituminous layer as they leave a smooth surface
Vibratory compaction equipments
It can be divided in to following types
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Equipment for concrete mixing
Concrete mixers
For small jobs conc. mixers are used to mix the ingredients of the concrete
Following type of concrete mixers are used in the construction
Hand felt tilting drum mixers
These are smaller capacity mixers ,aggregate cement and water fed in to the drum by hand
Loader fed tilting drum mixers
These are larger capacity as compared to hand fed mixers
These are fixed with the loading hopper operating by the wired rope for loading
Reversing drum mixers
This type of mixer is used on comparatively larger works
The mixer drum is horizontal and it is non tilting type
It has blades which work alternatively
Roller pan mixersThese mixers are primarily used for mortars ,the rollers and mixer blades rotate in a pan and not
only mixing material but also kneading and crushing it
Tunneling equipment
Selection of equipment
Selection of equipment for tunneling depends upon quantum of work involved
So that the tunneling work is carried out economically,speedly and safely
Muck loading
Mucking is the operation of loading the broken rock or earth for removal from tunnel
Mucking process can be done by the following e