construction techniques, equipment and practices

8/12/2019 Construction Techniques, Equipment and Practices

1/72

101303 CONSTRUCTION TECHNIQUES, EQUIPMENT AND PRACTICES 4 0 0 4OBJECTIVEThe main objective of this course is to make the student aware of the various constructiontechniques, practices and the equipment needed for different types of construction activities. Atthe end of this course the student shall have a reasonable knowledge about the variousconstruction procedures for sub to super structure and also the equipment needed forconstruction of various types of structures from foundation to super structure.UNIT I CONCRETE TECHNOLOGY 12CementsGrade of cements - manufacture of cementconcrete chemicals and ApplicationsMix design conceptmix design as per BIS & ACI methods manufacturing of concreteBatchingmixingtransportingplacingcompaction of concretecuring and finishing.Testing of fresh and hardened concretequality of concrete - Nondestructive testing.UNIT II CONSTRUCTION PRACTICES 13Specifications, details and sequence of activities and construction co-ordinationSite ClearanceMarkingEarthwork - masonrystone masonryBond in masonry - concrete hollow blockmasonryflooringdamp proof coursesconstruction jointsmovement and expansion jointspre cast pavementsBuilding foundationsbasementstemporary shedcentering andshutteringslip formsscaffoldingsde-shuttering formsFabrication and erection of steeltrussesframesbraced domeslaying brickweather and water proofroof finishes

acoustic and fire protection.UNIT III SUB STRUCTURE CONSTRUCTION 13Techniques of Box jackingPipe Jacking -under water construction of diaphragm walls andbasement-Tunneling techniquesPiling techniques - well and caisson - sinking cofferdam - cableanchoring and grouting-driving diaphragm walls, sheet piles - shoring for deep cutting - wellpoints -Dewatering and stand by Plant equipment for underground open excavation.UNIT IV SUPER STRUCTURE CONSTRUCTION 12Launching girders, bridge decks, off shore platformsspecial forms for shells - techniques forheavy decksin-situ pre-stressing in high rise structures, Material handling - erecting light weightcomponents on tall structures - Support structure for heavy Equipment and conveyors -Erectionof articulated structures, braced domes and space decks.UNIT V CONSTRUCTION EQUIPMENT 10Selection of equipment for earth work - earth moving operations - types of earthwork equipment -

tractors, motor graders, scrapers, front end waders, earth movers Equipment for foundation andpile driving. Equipment for compaction, batching and mixing and concreting - Equipment formaterial handling and erection of structures - Equipment for dredging, trenching, tunneling,TOTAL: 60 PERIODS


2/72

UNIT I CONCRETE TECHNOLOGY

TYPES OF CEMENT

Ordinary Portland cement

OPC33,OPC43 and OPC53 grade

Rapid hardening cement

Extra rapid hardening cement

Sulphate resisting cement

Portland slag cement

Quick setting cement

Low heat cement

Portland pazzolona cement

Air entraining cement

Colored cement

White cement

Hydrophobic cement

Masonry cement

expansive cement

Oil well cement

Redi set cemnt

Concrete sleeper grade cement

High alumina cement

Very high strength cement


3/72

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 sameworkability as an admixture free mix.

2. To achieve the same workability by decreasing the cement content so as to reducethe heat of hydration in mass concrete.

3. To increase the workability so as to ease placing in accessible locations4. 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 waterbecome available for workability.

2. Lubrication:

As these agents are organic by nature, thus they lubricate the mix reducing the frictionand increasing the workability.

3. Retardation:

A thin layer is formed over the cement particles protecting them from hydration and

increasing the setting time. Most normal plasticizers give some retardation, 3090minutes

Super Plasticizers:

These are more recent and more effective type of water reducing admixtures alsoknown as high range water reducer

The commonly used Super Plasticizers are as follows:

Sulphonatedmelamineformaldehydecondensates(SMF)


4/72

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 isa very cost-effective.

Polycarboxylate ether super plasticizers (PCE)

Typically give 2035%+ water reduction. They are relatively expensive per liter but arevery 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, andthe 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 ofhydration 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. SetAcceleratingAdmixtures,

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. HardeningAccelerators,

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.


5/72

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 periodwhen the concrete is plastic and can be placed.

At the end of the dormant period, the hydration rate increases and a lot of calcium silicate

hydrate 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. Usedon 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 furtherreactions between cement and water i.e. retards setting.

Air Entrained Admixtures:

An addition for hydraulic cement or an admixture for concrete or mortar which causesair, usually in small quantity, to be incorporated in the form of minute bubbles in the

concrete or mortar during mixing, usually to increase its workabilityand frost

resistance.

Air-entraining admixtures are surfactantsthat change the surface tension of the water.

Traditionally, they were based on fatty acid salts or vinsol resin but these have largelybeen 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.


6/72

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 Argillaceous

Calcareous materials used are

o Cement rocko Lime stoneo Marlo Chalko Marine shell

Argillaceous materials used are

o Clayo shaleo slateo blast furnace slag

Process manufacturing cement

Dry process

Wet process

Dry process

General

Adopted when the raw materials are quite hard

The process is slow an the product is costly

Process


7/72

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

Mixing

Burning

Grinding

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 isadjusted to ensure desired chemical composition


8/72

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 anddetermining their relative proportions with the object of producing concrete of certainminimum 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 particularwork for which the mix is designed.

Design of concrete mixrequires complete knowledge of the various properties of theseconstituent 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 experience

of 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.

The structural designer specifies certain minimum strength; and the concrete

technologist designs the concrete mix with the knowledge of the materials, site exposureconditions and standard of supervision available at the site of work to achieve this

minimum strength and durability.


9/72

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, mayhave 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 1954the 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 well2. With more or less identical procedure to rounded or angular aggregate3. To regular or light weight aggregates4. To air entrained or non-air-entrained concretes.

Manufacturing of concrete

IntroductionProduction of concrete requires meticulous care at every stage

The ingredients of good and bad concrete are same but good rules are notObserved it may become bad

Manufacturing of concrete includes the following stages1. Batching

2. Mixing3. Transporting4. Placing5. Compacting6. Curing7. Finishing


10/72

Batching

The measurement of materials for making concrete is known as batching.

Methods of batching Volume batching Weigh 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 granularmaterial.

Some of the sand in loose condition weighs much less than the same volume of drycompacted 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 connectedto the levers of spring loaded dials which indicates the load,

The weighing buckets are mounted on a central spindle about which they rotate

On large works the weigh bucket type of weighing equipment used ,the materials arefed from the over head storage hopper and it discharges by gravity.


11/72

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 andconsistency.

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 concretework medium or large scale concrete works .

Machine mixing is not only efficient it is also economical when quantity of concreteto be produced is large

Type of mixer for mixing concrete


12/72

Batch mixer

Continuous mixer

Batch mixer

Batch mixer produce concrete batch by batch with time interval

This is used in normal concrete work

Batch mixers are two types Pan type Drum type

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

Mortar pan]

Wheel barrow

Crane, bucket and rope way

Truck mixers and dumpers


13/72

Belt conveyors

Chute

Skip and hoist

Transit mixer

Pump and pipe line

Helicopter

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 roadconstruction.

If the distance is long or ground is rough it is likely that the concrete get segregated dueto 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 familiarsites in big cities

Rope way buckets of various sizes are used


14/72

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


15/72


16/72

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

concreteThey are truck mounted having a capacity of 4 to 7 m3

The speed of rotation of truck mixer is 4to16 rev/min


17/72

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 ofconcrete

Choosing a correct pump involves

Length of horizontal pipe

Length of vertical pipe

Number of bends

Diameter of pipe line

Length of flexible hose

Change in line diameter

Slump 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


18/72

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 vibratorFrequency of vibrator used


19/72

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

Check the reinforcements are correctly tied and placed

Check the reinforcement is having appropriate cover

The joints between plywoods or sheets properly plugged

Mould releasing agent should be applied

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 bucketreaching final place of deposition

The bottom is made to open by some mechanism and the whole concrete is dumpedslowly.


20/72

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 Ramming Tamping

Roding

Poking the concrete with about 2m long 16 mm dia rod to poke the concretereinforcement

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


21/72

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

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


22/72

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 scoop3. Bullet-nosed rod (600 mm long x 16 mm diameter)4. Rule5. Slump plate (500 mm x 500 mm)

Procedure of slump test for concrete:

Clean the cone. Dampen with water and place on the slump plate. The slump plate should beclean, firm, level and non-absorbent. Collect a sample of concrete to perform the slum test

.

Stand firmly on the footpieces and fill 1/3 the volume of the cone with the sample. Compactthe concrete by 'rodding' 25 times. Rodding means to push a steel rod in and out of theconcrete to compact it into the cylinder, or slump cone. Always rod in a definite pattern,working from outside into the middle.

Now fill to 2/3 and again rod 25 times, just into the top of the first layer.

Fill to overflowing, rodding again this time just into the top of the second layer. Top up thecone till it overflows.
http://www.aboutcivil.com/Properties-of-concrete-factors-affecting-them.htmlhttp://www.aboutcivil.com/Properties-of-concrete-factors-affecting-them.html


23/72

Level off the surface with the steel rod using a rolling action. Clean any concrete from aroundthe base and top of the cone, push down on the handles and step off the footpieces.

Carefully lift the cone straight up making sure not to move the sample.

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 samplefails 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 alwaysbe 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 concretecylinder for the compression test.

The strength is measured in Megapascals (MPa) and is commonly specified as a characteristicstrength of concrete measured at 28 days after mixing.

The compressive strength is a measure of the concretes ability to resist loads which tend tocrush it.

Apparatus for compression test

Cylinders (100 mm diameter x 200 mm high or 150 mm diameter x 300 mm high) (The smallcylinders are normally used for most testing due to their lighter weight)

1. Small scoop2. Bullet-nosed rod (600 mm x 16 mm)3. Steel float4. Steel plate

Procedure for compression test of concrete

Clean the cylinder mould and coat the inside lightly with form oil, then place on a clean, leveland firm surface, ie the steel plate. Collect a sample.


24/72

Fill 1/2 the volume of the mould with concrete then compact by rodding 25 times. Cylindersmay also be compacted by vibrating using a vibrating table.

Fill the cone to overflowing and rod 25 times into the top of the first layer, then top up the

mould till overflowing.

Level off the top with the steel float and clean any concrete from around the mould.

Cap, clearly tag the cylinder and put it in a cool dry place to set for at least 24 hours.

After the mould is removed the cylinder is sent to the laboratory where it is cured and crushedto test compressive strength

UNIT II CONSTRUCTION PRACTICES

Sequence of activities and constructionco ordinationPlanning

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


25/72

For prepare progress of construction each stage may be constructed under separate

contractionIt 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 groundbefore 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 thebuilding 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 of2m from the edge of excavation

When the string is stretched joining the corresponding pegs at the two extremities of the line theboundary 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 settingout right angles


26/72

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 20cmthick and 15cm wider than the width of the foundation

EXCAVATION

Excavation of foundation can be done by manually or with the help of special mechanicalequipments

Manually it can be done by the help of following equipments

o Spadeo Phawraho Pick axeo Crowbaro Rammero Wedgeo Boning rodo Sledge hammero Basketo Iron pano line and pins

Mechanically the excavation can be done by the help of following machineries

o Boom bucket dipper handleo Trencho Chain mounted bucketso Raking cuto Vertical cut

FOUNDATION

The foundation is he lower portion of the building, usually located below the ground level, whichtransmit the load of super structure to sub soil

Functions of foundation

Reduction of load intensity

Even distribution of load


27/72

Provision of level surface

Lateral stability

Safety against undermining

Protection against soil movements

Types of foundation

Shallow foundation

Deep foundation

Shallow foundation

If the depth of foundation is less than or equal to width of foundation it is called as shallowfoundation

Types of shallow foundation

Spread footing

Combined footing

Strap footing

Mat foundation

Spread footing

Spread footing is those which spread the super imposed load to of a wall or column over the large

area

Spread footing support either a column or a wall

It has the following types

Single footing

Stepped footing

Sloped footing

Wall footing with out step

Stepped footing for wall


28/72

Grillage foundation

Combined footing

A spread footing which supports two are more columnsis termed as combined footing

It has the following types

Rectangular combined footing

Trapezoidal combined footing

Combined column wall footing

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 combinedtrapezoidal footing becomes quite narrow

The strap beam does not remains in contact with soil and thus does not transfer any pressure tothe soil

Mat foundation

A raft or mat is a combined footing that covers the entire beneath a structureAnd 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 systemo Beam slab systemo Cellular system

Deep foundation

If the depth of foundation is equal to or more than the width of the foundation is called deepfoundation

Types

Deep strip rectangular or square footing

Pile foundation


29/72

Pier foundation or drilled caisson foundation

Well foundation or caissons

Deep strip footing

Whenever the depth of strip footing is more than the width it is called as deep strip footing

Pile foundation

it is a type of deep foundation in which the loads are taken to a low level by means of verticalmembers which may be timber or concrete or steel

Types of pile foundation

End bearing pile

Friction pile

Combined end bearing and friction pile Compaction 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 piles

Friction 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 thusforming the sand pile


30/72

Pier foundation

A pier foundation consist of a cylindrical column of large diameter to support transfer large superimposed loads to the firm strata below

Generally pier foundation is shallower in depth than the pile foundation

It has two types

o Masonryo 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 horizontalloads

Well foundations are caissons are hollow from inside, which may filled withstand and areplugged 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 Masonry2. Ashlar Masonry


31/72

1. Rubble Masonry:

The stone masonry in which either undressed or roughly dressed stone are laid in a suitablemortar 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:

Random rubble masonry Squared rubble masonry Dry rubble masonry

1. Random rubble masonry: The rubble masonry in which either undressed or hammerdressed stones are used is called random rubble masonry. Further random rubblemasonry 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 rubblemasonry. This is the roughest and cheapest type of masonry and is of varyingappearance. The stones used in this masonry are of different sizes and shapes.before lying, all projecting corners of stones are slightly knocked off. Verticaljoints are not plumbed, joints are filled and flushed. Large stones are used atcorners and at jambs to increase their strength. Once "through stone" is used forevery square meter of the face area for joining faces and backing.

Suitability:Used for construction of walls of low height in case of ordinarybuildings.

b. Coursed random rubble masonry: The random rubble masonry in whichstones are laid in layers of equal height is called random rubble masonry. In thismasonry, the stones are laid in somewhat level courses. Headers of one coursedheight are placed at certain intervals. The stones are hammer dressed.Suitability: Used for construction of residential buildings, go downs, boundarywalls etc.

2. Squared rubble masonry:The rubble masonry in which the face stones are squared onall 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 chiseldressed stones laid in courses is called coarse square rubble masonry. This is a


32/72

superior variety of rubble masonry. It consists of stones, which are squared onall 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 ofstone is easily available.

b. Un coursed square rubble masonry: The squared rubble in masonry whichhammer dressed stones are laid without making courses is called un coursedsquare rubble masonry. It consists of stones which are squared on all joints andbeds by hammer dressing. All the stones to be laid are of different sizes.Suitability: Used for construction of ordinary buildings in hilly areas where agood variety of stones are cheaply available.

3. Dry rubble masonry: The rubble masonry in which stones are laid without using anymortar is called dry rubble masonry or sometimes shortly as "dry stones". It is an ordinarymasonry and is recommended for constructing walls of height not more than 6m. In casethe 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 asashlars 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 ofstones.

Suitability: This masonry is used for heavy structures, architectural buildings, high piers andabutments of bridges.

Ashlars masonry is further sub divided into the following types:

Ashlars fine or coarse ashlar masonry Random coarse ashlars masonry Rough tooled ashlar masonry Rock or quarry faced ashlars masonry Chamfered ashlars masonry Block in coarse masonry Ashlar facing

Ashlar fine or coursed ashlar masonry: In this type of stone masonrystone blocks of same height in each course are used. Every stone is finetooled on all sides. Thickness of mortar is uniform through out. It is anexpensive type of stone masonry as it requires heavy labor and wastageof material while dressing. Satisfactory bond can be obtained in this typeof stone masonry.

Random coursed ashlar masonry: This type of ashlar masonryconsists of fine or coursed ashlar but the courses are of varying thicknesses, depending upon the character of the building


33/72

Rough tooled ashlar masonry: This type of ashlar masonry the sides ofthe 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 issimilar to rough tooled type except that there is chisel-drafted margin leftrough on the face which is known as quarry faced.

Chamfered ashlar masonry: It is similar to quarry faced except that theedges are beveled or chamfered to 450 for depth of 2.5 cm or more.

Block-in course masonry: It is the name given to a class of ashlarmasonry which occupies an intermediate place between rubble andashlars. The stones are all squared and properly dressed. It resemblesto coursed rubble masonry or rough tooled ashlar masonry.

Ashlar facing:Ashlar facing is the best type of ashlars masonry. Since this is type ofmasonry is very expensive, it is not commonly used throughout the whole thicknessof 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

Brick

MortarTypes of mortar

Cement mortar

Lime mortar

Cement-lime mortar


34/72

Lime surkhi mortar

Mud mortar

Types of bricks

Traditional bricks

Modular bricksTraditional 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 variesfrom 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

First class brick

Second class brick

Third class brick

Bonds in brick work

Stretcher bond Header bond English bond Flemish bond Facing bond English crossing bond Brick on edge bond Dutch bond Racking bond Zigzag bond Garden wall bond

Stretcher bond

The length of the brick its along with the face of the wall\

This pattern is used only for those wall which have thickness of half brick


35/72

Header bond

The width of the bricks are thus along the direction of the wall

This pattern is used only when the thickness of the wall is equal to one brick

English bond

It is the most commonly used methodthis bond is considered to be the strongest

This bond consist of alternate course of stretchers and headers

Alternative courses will show either headers or stretchers in elevation

There is nop vertical joint

Every alternative header come centrally over the joint between two stretchers in corse in

below

Since the number of vertical joint in the header course twice the number of vertical joints in

stretcher course ,the joints in the header course are made thinner than the joints in thestretcher courseFlemish bond

Inthis type of course is comprised of alternative headers and stretchers

Types of Flemish bond

Double Flemish bond

Single Flemish bond

Double Flemish bond

Every course consist of headers and stretchers placed alternatively

The facing and backing of the wall in each course have the same appearance

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 headercourse tis provided at a vertical interval of 90 cm


36/72

English cross bond

This is he modification of English bond to improve the appearance e of the wallBrick on edge bond

This type of bond uses stret

dutch bond

DAMP PRPOOF COURSEIntroduction

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 moisturepresent 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 andtravel down

Leaking roofs will also permit the water to enter in the wall

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 itwould completely deface the decoration of the wall

CondensationDue to condensation of atmospheric moisture water is deposited on theWalls, floors and ceilings


37/72

Methods of damp proofing

Membrane damp proofing

Integral damp proofing

Surface treatment

Cavity wall construction

Guniting

Pressure grouting

Membrane damp proofing

Introducing a water repellent membrane or damp proof course between the source of dampnessand the part of the building adjacent to it .

Dpc may be consist of flexible materials such as bitumen, mastic asphalt, bituminous felts, plasticare polythene metal sheets .

Integral damp proofing

This consist of adding certain water proofing compounds of materials to theconcrete mix so that it becomes impermeable

These water proofing compounds made fromChalk, talk and fullers earth

Compounds like alkaline silicates, aluminum sulphate, and calcium chloride

Surface teatement

This consist of application of layer of water repellentsubstance or compounds on the surfacethrough 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


38/72

guniting

This consist of depositing under pressure ,an impervious layer of rich cement mortar over theexposed 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 helpof 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 presentinto the structural components

This method is quite effective in checking the seepage of raised ground water

Materials used for damp proofing course

Hot bitumenMastic asphalt

Bituminous or asphaltic feltsMetal sheetsCombination of sheets and bituminous felts

BricksStones

MortarCement concrete

Plastic sheets

FLOORS

The purpose of floor is to provide a level surface capable of supporting the occupants of thebuilding, furniture, equipment and some time interior wall

The floor must satisfy the following requirements

Adequate strength and stability

Adequate fire resistance

Sound proof

Damp resistance

Thermal insulations

Components of a floor

Sub floor, basecourse or floor base


39/72

Floor covering or flooring

Selection of flooring materials

Factor that affect the choice of flooring

Initial cost Appearance Cleanliness Durability Damp resistance Sound insulation Thermal insulation Fire resistance Smoothness Hardness Maintenance

Types of flooring

Mud flooring and muram flooring Brick flooring Flag stone flooring cement concrete flooring Terrazzo flooring Mosaic flooring Tiled flooring Marble flooring timber flooring Asphalt flooring

Rubber flooring Linoleum flooring Cork flooring Glass flooring Plastic or pvc 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 inwinter

Over a well prepared ground 25 cm thick selected moist earth is spread and it rammed well tocompacted thickness of 15cm


40/72

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 2.5cm 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

Flag stone flooring

Flag stone is laminated sand stone available in 2cm to 4cm thickness in the form of stone slab of30X30 cm or 45X45cm and 60X60 cm

This type of works also called paving.The stones are laid on concrete base the subsoil is properly compacted over which 10 to of limeconcrete or lean cement concrete is laid

Cement concrete flooring

This is commonly used for residential, commercial even industrial building..

It is moderately cheap quite durable and easy to construct

The floor consist of two components

Base concrete

Topping or wearing surface

The base course ma be 7.5 to 10 cm thick

The topping consist of 1:2:4 cement concrete

Terrazzo flooring

Terrazzo flooring is another type of floor finish that is laid in thin layer over concrete topping


41/72

It is very decorative and good wearing properties

Terrazzo is a specially prepare concrete surface containing cement and marble chips in theproportion to 1:1 1/4 to 1:2

When the surface has set the chips are exposed by grinding operation

Mosaic flooring

Mosaic flooring Is made of small pieces of broken tiles of china glazed or of cement or of marblearranged in different pattern

These pieces are cut to desired shape and sizes

a concrete base is prepare as in the case of concrete flooring over that 5to8 thick lime surkhimortar is spread over an area, over this 3mm thick cementing paste is layered and is left to dry

about 4 hours,

,there after small pieces of broken tiles or marble pieces of different colors arranged definite

pattern and hammered in different layers

Tiled flooring

Tiledflooring is constructed from square ,hexagonal or other shapes made up of clay cement

concrete and terrazzoThese 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 andhospitals ,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 auditoriumEtc


42/72

These are not commonly usedin India because its costlier

But hilly area where wood is available and temperature drops very low timber flooring is quitecommon

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 mtemporary structures needed to support trhe platforms over which the work man sit and carry othe work

These temporary structures constructed very close to the wall is in the form of imber o steel frame

work commonly called as scaffoldings

Components of scaffoldings Ledgers Braces Put logs Transoms Boarding Guard rail Toe board

Single scaffolding or brick layer scaffolding

Double scaffoldings or masons scaffoldings Cantilever or needle scaffoldings Suspended scaffoldings Trestle scaffolding Steel scaffolding

Patented 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


43/72

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 thefirst one

Put logs are the supported on both the supports, rakers and cross braces are provided to make thescaffolding more strongIt also called as independent scaffoldings


44/72

Cantilever or needle scaffolding

Cantilever supports can be used under following circumctances

Ground is week to support standardsConstruction of the upper part of the wall is to be carried outIt 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


45/72

Trestle scaffolding

Such type of scaffoldings are used for painting and repairing work inside the room up to a heightof 5m

The working platform is supported over the top of movable contrivances such as tripods laddersetc

Steel scaffolding

Steel scaffolding is practically similar to the timber scaffolding, here wooden members arereplaced 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 marketThos 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

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


46/72

Types of roof trusses

King post truss

Here t hecommon 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 endThe 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 of5m to 9m

Queen post truss


47/72

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 asto permit light in to the interior

Centeringand shutteringShuttering 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 concreteand plain concrete

Requirements of shutteringThe 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


48/72


49/72

form work for stairsShuttering 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 forfunctional, aesthetic, or budgetary reasons.

Roofing accessories are largely made from aluminum, steel, copper, or PVC vinyl. They include arange of products including

Rain gutters and Drains and guards

Flashing or weatherproofing materials

Roof caps

Drip edges

Ridges and shingles

Chimney caps

Leader boxes

Finials and turrets

Weathervanes.

Rain gutters and Drains and guards


50/72

Rain gutters, drains and guards are roof finishing accessories that collect and divert rainwateraway from the roof and building foundation.

These types of roof finishing accessories may also reduce erosion, prevent leaks in thefoundation or basement, reduce water exposure on painted surfaces, and collect water foradditional 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 ofwater 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 rooffinishing accessories

. Roof caps provide ventilation via the rooftop. They are commonly made from copper orgalvanized steel, and often include an insect screen.

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 orupper 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 boxaccessories are used with gutter systems to hide or diminish the sight of leader elbows, and areavailable 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 fordecoration. Turrets are often designed to hold clocks or bells.

Similarly, weathervanes are another type of roof finishing accessory often used for decoration atthe highest point of the roof. Weathervanes are not solely used for decoration, however, as theyalso point to the direction of the wind. Other, unlisted types of roof finishing accessories may alsobe available.

ACOUSTICS


51/72

Acoustics is the science of sound ,which deals with origin ,propagation and auditory sensation ofsound and also with design and construction of different building units to set optimum conditionfor 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 floorarea of any combustible parts of the building itself

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


52/72

Fire proof door shall conform rigidly to the fire safety requirements

Electrical and mechanical lifts while reliable undr normal condition may not always berelied on escape purpose

Lift shafts and stairways invariably serve as flues are tunnels thus increasing the fire byincreased 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

UNIT III SUB STRUCTURE CONSTRUCTION 13

TECHNIQUES OF BOX JACKINGNecessity of this technique

When the increasing demands for various forms of transport infra structure to be constructed incongested 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 withoutdestruction

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

OPERATONS

The box shaped tunnel structures are pre fabricated units which are pushed into soil by hydraulicjack

Soil is excavated at the advancing face by manual means or by excavatorsTo avoid settlements of over laying roads or rail track soil is excavated after it enters the cuttingheads

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


53/72

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 JACKINGIn 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 liningsystem 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 drillingsystems controlled from a shaft or a pit to push the tunnel lining segment from the shaft or pit

these techniques are often referred to us pipe jacking or micro tunneling techniques andequipments

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 hydraulicjacking system

Horizontal auguring refers to a similar technique in which the man is replaced by a horizontalcontinuous flight helical auger

INSTALATIONThe pipe sections are moved forward by hydraulic jacking and the miniature TBM derive its

reaction from these sectionPipe 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 diaphragmis 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.


54/72


55/72

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 routeo Height of mountain should be lesso Mark the points on the mountaino Transfer the tunnel inside the mountain by making of required deptho Checking the tunnel cross section whether equal every where

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 thesoil

Pile driving an be done by two methods

Using hammering


56/72

Using pile driver

Hammering

Heavy bl0w is given by means of a hammer

Variety of hammers available to perform some of the acion

Drop hammer Single acting hammer Double acting hammer Diesel hammer and Vibrating 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

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 bysteam 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


57/72

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 toseparate the vertical member of the building

The piles are inserted by some machine the depth of the piles can be increased by properjoints 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 defensework

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 thedepth 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

DEWATERING

DEFINITIONWhen 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 bypumping 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


58/72

Dewatering of soil by temporary lowering of water table using wells and pumps prior excavationas depleted in figure

Allowing water to reap into excavation area, collecting it in sumps and pumping it out. Beforethat adequate steps have to be taken to support the soil on sides of the excavated area, to preventwashing away of fines and have sufficient space for the work area.

Making the soil around excavated zone impermeable by technique such as grouting are freezingso that inflow of water is stop are minimized.

INSTALATION TECHNIQUE

Sufficient size and capacity of dewatering system is necessary to lower and maintain groundwater 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, toadequately 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 not endanger

portions of work under construction or completed.

For dewatering purpose, well points deep well, caissons and tunnels are used.

WELL POINTSDEWATERINGWhen construction operation have to be excited below the ground water table level. Dewateringof 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 dryworking area the two methods used most often for lowering water table below the excavationlevel are the well point method and the deep well method.

WELL POINT METHOD

:


59/72

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 inthe 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 groundsurface 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.

UNIT IV SUPER STRUCTURE CONSTRUCTION

BRIDGE DECKS

The principal function of a bridge deck is to provide support to local vertical loads (fromhighway 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) continuousacross 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.


60/72

Continuity ensures that whether or not it has been designed to do so, it will participate in

the overall structural action of the superstructure.


61/72


62/72

Singly curved

Doubl curved

Cylindrical shells

Singly curved

It can be used for rectangular shape buildings, shells represents the roof of the building

Dome storage tank for water and petroleum is example for single curved

Doubly curved

For doubly curved structures the super structure should be in hexagonal or circular shape

Cylindrical shape

These ae just modification of pitched roof and frequently emloyed in modern ageconstruction

It has two types

North light shell roof

Barell vault shell roof

Both are different to provide lighting effect in factories

In barell vault ventilation s provided in middle

Off shore platforms

Off shore platforms are self contained platforms with adequate facilities for drilling, derrick,

drilling mud electric power, pumping equipment for the offshore construction these are artificialfacilities above the elevation of off shore platforms


63/72

Off shore platforms can be classified as

Fixed Off shore platforms

Bottom supported structures

Compliant platforms and floating platforms

Construction principles of offshore platformsSelection of operational criteria

Selection of environment

Environmental factors like

Storming wind velocity

Storming wave height

Tidal conditionsBefore 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 platformconstructions.

The fixed platforms can be classified intoJacket or template structures

Gravity structures

ERECTING LIGHT WEIGHT COMPONENTS ON TALLSTRUCTURES

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 buildthe 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 ofconstructions.

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 becarried out to connect struts or joist and track together


64/72

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 structureitself 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 aerialtransporting and handling

Aerial cable way

Helicopter

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

Classification

Singly curved

Doubl curved

Cylindrical shells

Singly curved

It can be used for rectangular shape buildings, shells represents the roof of the building

Dome storage tank for water and petroleum is example for single curved

Doubly curved

For doubly curved structures the super structure should be in hexagonal or circular shape

Cylindrical shape


65/72

These ae just modification of pitched roof and frequently emloyed in modern age

construction

It has two types

North light shell roof

Barell vault shell roof

Both are different to provide lighting effect in factories

In barell vault ventilation s provided in middle

UNIT V CONSTRUCTION EQUIPMENT

Construction equipments

Types of earth moving equipment

Classified into following types

Production equipment

Equipment used for digging and moving

Service equipment

Dozers and motor girders

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 typeRubber tired or wheel type


66/72

The tractor is multi purpose machine

Light models are used for agricultural or short haulage worksHeavy 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

BulldozersDozers a

construction techniques, equipment and practices

Documents