advanced building technology

7/30/2019 Advanced Building Technology

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1Advanced Construction Technology

BTEC HND in Quantity Surveying & Construction Economics

Task 01

Scenario 1

Tourism company X has proposed ten storey hotel building in Negombo

which consists of a living area, dining area, kitchen ,stores, staff rest room

and common bath room and toilet block, washing area ground floor and

twenty rooms with attached bath room in each upper floor. Air conditioning

will be provided to dining and living area in ground floor and all rooms in

upper floor. It has been decided to provide hot water to all room other than

cold water. Authority supplied main water supply is available but main

sewer lines are not available. Extend of landing sufficient to provide internal

roads, parking and other facilities. Company X has awarded the contract to

consultant company Y for the necessary investigations and designing thebuilding according to their requirements.

Task 1.1

Describe the method of cold and hot water supply systems of the building.

Evaluate all factors which are to be considered when designing cold and hot

water supply system for this hotel building by considering the given information.

Assess the requirement of cold and hot water supply for each floor the building

and design the suitable system for ten storey hotel building along with detail

sketches. (P2.1)

Water supply

Water supply system receives water from sources such as lakes, rivers, reservoirs, wells or sea

through desalination. Water is pumped from the source and then it is sent to the treatment plant

for purification. After purifying, it is sent to the elevated tanks for distribution. Distribution

network is used to distribute water to houses.

Cold water systems

i. Mains pressure cold water system (Direct system)

In this system, water will be supplied under mains pressure. For efficient operation, a high

pressure water supply is essential particularly at periods of peak demand. Pipe work is minimal

and small storage cistern can be installed, if necessary, for the hot water supply. Drinking water

is available at every draw off point and maintenance valves should be fitted to isolate each

section of pipe work.


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ii. Cistern feed system (Indirect system)

In the cistern feed system, water is supplied to a cistern (overhead tank) through a supply pipe.

A cistern is a liquid storage container which is open to the air and in which the liquid is at normal

atmospheric pressure. The water supply to the cistern is controlled by a ball valve that is fixed to

the cistern, above the waterline, and connected to the cold supply through a valve. As water is

drawn from the cistern the ball falls and the arm activates the ball valve that opens to let water

in to the cistern. When water has risen to the water line, marked on the cistern wall, the ball and

arm rise to close the valve.

Cistern can be made of Galvanized steel, Stainless steel, Plastic, masonry or concrete.

Hot water system

Hot water can be either be granted by central boiler plant and stored (centralized system), or

produced close to the point of use (decentralized system).

i. Centralized system (Storage water system)

Water is heated either directly in the storage cylinder, for example by an electric immersion

heater or from a remote boiler. The two main types of system are the open vented and the

unvented.

a. Open vented (Indirect system)

The open vented water system (indirect) relies on a large volume of stored water. The head ofstored water is usually sufficient to push water down the pipe that feeds the water storage

cylinder and back up to any tap or shower outlet, providing it is lower than the stored water

level.

b. Unvented (Direct system)

The unvented (direct) stored water out of the cylinder or though the pipe circuit to the tap or

shower outlet.

ii. Instantaneous system

Tank less water heaters, also called instantaneous, continuous flow, inline, flash, on demand orinstant on water heaters, instantly heat water as it flows though the device, and do not retain

any internally expect for what is in the heat exchanger coil.


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According to proposed ten storeys hotel building there are twenty rooms in each floor and in a

hotel water consumption rate per head per day is 180 liters (per bed).

Therefore the maximum water consumption rate for all the hotel rooms = 180x20x9x2

= 64800 liters

Assumed number of staff members = 50

Total amount of water consumption for staff members = 50x135

= 6750 liters

Therefore the total amount of water consumption for the whole hotel = 64800 + 6750

building

= 71550 liters

If it is assumed that thirteen rooms in each day in each floor are occupied with the hotel

customers

The minimum amount of water consumption rate = 180x13x9x2

= 42120 liters

Water consumption for staff members = 6750 liters

Therefore the minimum amount of water consumption for the proposed = 42120 + 6750

hotel

= 48870 liters

There should be some excess water in the storage of water tanks due to water cut by the water

board

Therefore the minimum amount of water which should be stored in water = 48870x2

tanks

= 97740 liters

According above considered details I am suggesting an indirect water storage system with a

water sump for cold water and solar water system for hot water as the proposed hotel location is

in Negombo area which has a hot weather condition.


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Designed cold and hot water system diagrams for the hotel building


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Task 1.2

It is known that waste water supply system is necessary for any building. Select

suitable waste water systems for this ten story hotel building and compare theirimportant features. Propose a suitable system for waste water and soil water

disposal for this hotel block. Provide necessary sketches to show the proposal.

(P2.2)

There are four main drainage systems used in buildings.

A. Single stack system

B. One pipe system

C. One pipe partially ventilated system

D. Two pipe system

Single stack system

In this system, only one vertical soil pipe is used. The wastes from baths, sinks, etc. as well as

foul matter from the WC are discharged in one single pipe, called the soil and waste pipe. There

is no separate pipe for ventilation purposes. This system proves economical as only one pipe to

be provided. The effectiveness of the system totally depends on the depth of water seal. No


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water seal should be less than 75mm.

Fig Single stack system

One pipe system

In this system, a vent pipe is provided and traps of all water closets, basins, etc. are completely

ventilated. Waste connections from sinks, baths, wash basins and the soil pipe branches from

W.C.s and urinals are all connected in to one main pipe. Since all the traps are ventilated by

separated vent pipe, this method proves to be more effective than the single stack system.


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Fig One pipe system

One pipe partially ventilated system

This is modified form of the single stack system and one pipe system. In this system, the waste

from W.C., basins, sinks, etc. is discharged in to one common soil and waste pipe. However in

addition, a relief vent pipe is also provided which provides ventilation to the traps of water

closets. The traps of basins etc are not directly connected to the vent pipe.

Two pipe system

In this system, separate soil pipe and waste pipe are provided. The discharge from W.C. is

connected to the soil pipe while the discharge from baths, sinks, lavatory basins, etc. is

connected to the waste pipe. The entire traps are completely ventilated by providing separate

ventilating pipes. Soil pipes and waste pipes are provided with separate vent pipes. The system

thus requires from pipes and hence proves very costly.


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Fig Two pipe system

According to the details of each waste water system I would suggest the TWO PIPE WASTE

WATRE SYSTEM as the best waste water system for the proposed hotel building.

Reason for choosing the two pipe waste water system

Even though this pipe system is a costly design, in case of any maintenance, maintaining

process will be easier in this pipe system. Since this is a hotel building with twenty hotel rooms

in each floor and all the pipes are connecting to the waste water system and the laying of pipes

are bit advance two pipes waste water system will reduce the complexity and it will be the best

waste water system for this proposed hotel building in Negombo area.


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Task 1.3

Company Y has indentified the requirement of electrical installation for this hotel

building. Explain how main electricity is provided to the building by naming all

essential components. (P2.3)

Main electricity supply starts from a hydro power plant or a thermal power plant and transmitted

to power towers through transmission lines then the alternative current is transmitted to

electrical poles through transmission lines finally alternative current comes to the building

through distribution lines. In Sri Lanka we use 230V/50Hz in single phase and 440V/50Hz in


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three phase systems. The Ceylon Electricity Board directly looks after high voltage transmission

in Sri Lanka.

Transmission lines Distribution line

Power plant Power towers Electrical poles Building

A consumers electrical installation begins at the connection of the meter. From the meter 230V

supply is run to the consumers installation, which includes consumers unit (main switch, circuit

breakers, distribution of supply to the various circuits) and the necessary separate circuits for

lighting, heating and power.

Main components in Electrical installation

1. Isolated main switch

Main switch effectively cuts off all voltages to the whole of an electrical installation.

2. Distribution

Three distribution conductors housed in the consumers unit are connected separately to the

3. Main earthling thermal

This provides the necessary earth connection to the various circuit protective conductors,

commonly called earth, to protect the insulation against the damage and danger of fire shock to

persons.

4. Over current protective device

In the live conductor to each circuit cable run from the distribution conductor, is a fuse or circuitbreaker as protection against current greater than that which the circuit tolerate. The purpose of

this device is to course a break in a circuit as protection against damage to conductors and

insulation by overheating coursed by excessive currents.

5. Fuse


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The fuse is a type of over current protection device. Its essential component is a metal wire or

strip that melts when too much current flows, this breaks the circuit in which it is connected, thus

protecting the circuits other components from damage due to excessive current.

The fuses are available two types

i. Rewire able fuse

ii. Cartridge fuse

Miniature Circuit Breaker (MCB)

A circuit breaker is an automatically operated electrical switch designed to protect and

electrical circuit from damage cause by all overload or short circuit. Its basic function is to detect

a fault condition and by interrupting continually, to immediately discontinue electrical flow. Unlike

a fuse, which operates once and then has to be reputed a circuit breaker can be reset (either

manually or automatically) to resume normal operation.

Task 1.4

What are the types of Air Conditioning systems and active fire systems company

Y can select for the building? (P2.4), (P2.5)

Types of air conditioning systems

1. Window air conditioner


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This is the most commonly used air conditioning system for single rooms. In this air conditioner

all the component all the components, namely the compressor, condenser, expansion valve or

coil, evaporator and cooling coil are enclosed in a single box. This unit is fitted in a slot made in

the wall of the room.

Fig Window type air conditioning units

2. Split air conditioner

The split type unit is comprised of two parts

Outdoor unit fitted outside the room, houses components like the compressor, condenser and

expansion valve.

Indoor unit comprised with the evaporator or cooling coil and the cooling fan. Further, the

present day split units have aesthetic looks and add to the beauty of the room. This system can

be used to cool 1 or 2 rooms.

Fig Split type air conditioner unit

3. Central air conditioning system

Central air conditioning system is used for cooling big buildings, houses, offices, entire hotels,

gyms, cinema halls, factories, etc. If the whole building is to be air conditioned, HAVC engineers

find that putting individual units in each of the rooms is very expensive initially as well in the long

run. The central air conditioning system is comprised of a huge compressor that has the

capacity to produce hundreds of tons of air conditioning. Cooling big halls, malls, huge spaces,

galleries, etc. is usually feasible with central conditioning units only.


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Fig - Central air conditioning unit

Fire security systems

Fire safety decisions are mainly dominated by building codes, associated stand of practice and

insurance considerations. This is natural because they have been a part of the building process

for nearly a century and have demonstrated success in reducing fire losses.

1. Active fire defenses

2. Passive fire defenses

Active fire defenses

A device or action that must receive a stimulus to act in a real or a perceived fire condition

i. Automatic detection and alarm system

ii. The automatic sprinkler system

iii. Hose reels system

iv. Fire department operations

v. Special hazard, automatic suppression system

vi. Occupant activities

vii. Special features

Passive fire defense


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A building component that remains fixed in the building whether or not fire emergency exists.

i. Insulation of structural elements to prevent failure.

ii. Barriers to prevent extension of the flame heat or smoke gas from one space to

another

iii. Opening protective in barriers, such as doors or dampers, to inhibit the movement of

flame, heat, smoke or gases into the adjacent spaces.

iv. The egress system.

Task 2Scenario 2

10 km major road projects is propose to contact between to main town in North

Central province. Main features of the road structure are given blow.


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i. 10 Km road stretch has to be carried out by forming sub grad has per the

design levels of the road.

ii. 6.0m carriage way will be with 1.0m shoulders on both sides of the road.

iii. Camber is 2% for road pavement and shoulder.

iv. Road structure contains 150mm thick base course, 250mm thick sub base and

150mm thick shoulders.

v. Two culverts are to be contraction for 500mm and 2500mm width of canal

vi. Approximately 1.0m height of fill, 200m length retaining walls for both sides

are to be provided one stretch of the road.

Task 2.1

What are the basic components of a road and draw the cross section of the road

of indicting them clearly. When designing the road stretch it is necessary to

specify the materials of each components of the road. Assess suitable materials

sub-base and bass course construction of the road and select one method with

justification for base course of the above road. (P3.1)

In roadconstruction Aggregates, Bitumen and the Soil are the major construction materials.

Main component of a road

i. Embankment

Whenever it is required to raise the grade line of a highway above the ground level from

considerations of topography, vertical alignment, ground water depth and drainage, etc. an

embankment is needed.

ii. Sub grade

Sub grade the layer immediately below the embankment and it will be the main load bearing

layer of pavement structure. The material using to construct base is usually crushed aggregate.

iii. Sub base


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Sub base is the layer immediately below the sub grade. The materials using for sub base should

be a permeable material. It should ensure that, if water penetrates through base, proper

drainage of water outside the roadway and it also should drain water coming below outside of

roadway. The commonly used material for sub base is gravel.

iv. Carriageway

The portion of the road for the movement of vehicles

v. Shoulders

The portion of the roadway continuous to the traveled way for the accommodation of stopped

vehicles, for emergency use, for lateral support of base and surface courses

vi. Side drains

Side drains are one of the important parts in road construction and it is used to drain out the rain

water on the surface of the road which can cause weak spots on the road way.

Suitable materials for sub base construction

Aggregates

Nominal sizes used 50mm (2), 37.5mm (11/2), 19mm (3/4), 12.5mm (1/2)

Suitable materials for sub base construction

The materials using for sub base should be a permeable material. The commonly using material

for sub base is gravel. Even it can crushed rock or stabilized sub graded material also can be

used.

According to RDA general specifications construction materials for sub base

Sub base type 1

California Bearing Ratio value should be greater than 20

The Plasticity Index and LL of the soil should be less than 15% and 40% respectively.

Sub base type 2


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California Bearing Ratio value should be greater than 8

The Plasticity Index and LL of the soil should be less than 15% and 40% respectively.

Justification for base course of proposed major road project

The sub base or sub base surface should be prepared to the required lines and levels

(thickness of sub base is 250mm) and should be cleaned.

Prior to spreading the aggregate will be spread evenly on the aggregate base, a partial

width of the shoulder will be constructed to the elevation of the top of each compacted

layer of base.

The selected aggregate will spread evenly on the prepared surface.

The aggregate will be compacted using a steel wheeled roller and rolling will be done bya series of overlapping longitudinal passes of the roller working from the edge towards

center.

The 19mm or 12.5mm choker stones will be spread evenly and rolled to ensure that the

stones are well embedded in the surface interstices of the base course. While the rolling

is being done, the surface shall be wetted and lightly brushed so as to ensure that the

finer aggregate are worked in to the interstices.

Hot bitumen application over the single size aggregate base

There will be application of two coats over the single size aggregate base

First coat at the rate of 2 Ltrs/Sqm

Second/subsequent coat 1 Ltrs/Sqm

Each coat will be blinded with sand

Application of the blinder can be done manually or using mechanically sprayer

Task 2.2


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What is mean by road drainage? Give the type of cross drainage structures in

road construction. Visit any major road observe the failure due to road drainage

collect all information alone with necessary photographs. Evaluate the weakness

critically and propose the remedy. (P3.2)

Road drainage is a method of discharging rain water from roads.

Cross drainage

The function of the cross drainage structure is to ensure that the runoff water is discharged

across the road from one side to the other, as quickly as possible, without causing undue

pending, parallel flow along the road embankment, cover topping of the road embankment or

erosion of the portion of the road.

Cross drainage structures can be divided into following categories

i. Cross drainage

If the discharge is low, concrete drains can be constructed across the road to provide drainage

and these drains will be covered with concrete slabs having enough strength to bear traffic

loads.

ii. Culverts

A culvert is a closed conduit used to convey water from one area to another, usuallyfrom onside of a road to the other side.

Fig - RCC pipe culverts

iii. Causeways


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A causeway is a raised road or track across low or wet ground.

iv. Bridges

A bridge is a structure built to cross over an obstacle. Obstacles can be streams, rivers, valleys

or any other physical obstacles.

Task 2.3


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What is the main function retaining wall? Give commonly used retaining walls in

construction. Identify and evaluate all factors which have to be considered when

designing the retaining wall for the above road project. Propose a suitable type

with justification. (P3.3)

Retaining wall can be any wall construction which is constructed for retaining material tomaintain a difference in elevation. The main function of a retaining wall is to stabilize the hill side

and prevent erosion.

Retaining walls can be permanent or temporary. Temporary retaining structures are used to

retain earth temporary such as coffer dams.

When heavy runoff is present, retaining wall helps to reduce erosion.

Common types of retaining walls

i. Abutment

ii. Cantilevered wall

iii. Crib walls

iv. Gabion

v. Gravity wall

vi. Masonry wall

vii. Soil nailing

viii. Prefabricated walls

ix. Sheet pile walls

x. MS walls (mechanically stabilized)

a. Panel Walls,b. Concrete Block Wallsc. Temporary Earth Walls

Gabion walls


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Gabions are multi-celled, welded wire or rectangular wire mesh boxes, which are then, rockfilled, and used for construction of erosion control structures and to stabilize steep slopes. Theirapplications include,

o Retaining walls,o Bridge abutments,

o Wing walls,o Culvert headwalls,o Outlet aprons,o Shore and beach protection walls,o Temporary check dams.

Fig Gabion wall

Gravity Walls


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Gravity walls are the earliest known retaining structures. They are built from solid concrete orrock rubble mortared together. The lateral forces from backfill is resisted by the weight of wallitself, and due to their massive nature, they develop little or no tension. Therefore, they areusually not reinforced with steel. Gravity walls are economical for heights up to 3 m (10feet).

Fig - Gravity Walls

Crib Walls


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Crib walls are made up of interlocking individual boxes made from timber or pre-cast concrete.The boxes are then filled with crushed stone or other coarse granular materials to create a freedraining structure. There are two basic types of crib wall:

o Timber o Reinforced pre-cast concrete

Fig - Crib Wall

Cantilever Walls.


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Cantilever walls are built of reinforced concrete and are typically composed of a horizontalfooting and a vertical stem wall. The weight of the soil mass above the heel helps keep wallstable. Cantilever walls are economical for heights up to 10 m (32 feet).

Fig - Cantilever Walls

Sheet Pile Walls

Used to build continuous walls for waterfront structures and for temporary construction wallheights > 6 m if used with anchors, can be made of steel, plastics, wood, pre-cast concrete.

The advantages of using steel sheet-piling:

o Provides higher resistance to driving stresses;o Is of an overall lighter weight;

o Can be reused on several projects;o Provides a long service life above or below the water table;o Easy to adapt the pile length by either welding or boltingo Their joints are less apt to deform during driving.


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Soil nailing (In-Situ Walls)

These walls do not rely on their mass to retain the soil. Rather, they rely on their flexuralstrengths to retain the soil. They are supported by penetration into the soil or by anchoringsystems. For example, soil nailing.

Fig Soil nailing


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Mechanically Stabilized Earth (MSE) Walls

These walls are among the most economical, and most commonly constructed. Contrary toother types, the MSE walls are supported by the soil, and not the other way around. They aresupported by selected fills (granular) and held together by reinforcements, which can be eithermetallic strips or plastic meshes.

The MSE Categories

o Panel Walls,o Concrete Block Walls,o Temporary Earth Walls.

Fig Concrete Block Walls,

Factors to be consider when deciding a retaining wall


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Task 2.4

Describe the type of bridges and list out the main components in a bridges. It is

necessary to design a bridge for the above projects. What are the important

factors to be considered when designing the foundation of a bridge? Give the

type of foundation that can be used for bridge construction and explain themethod of constructing one type (P3.4), (P3.5)

Types of bridges

i. Beam or girder bridges

A beam bridge is the most common and most basic type of a bridge. A beam bridge consists of

a horizontal beam that is supported at each end with abutments and in the middle by piers. A

beam bridge usually built with concrete, steel or combination of both. Beam Bridge is most

economical type of the bridge with a limited span about 250m.

ii. Arch bridge

Arch bridge is the one of oldest type bridges in bridge construction. The specialty in arch bridge

is that the load and weight are carried outward along the curve of the arch to the support at

each end, instead of pushing straight down. These supports carry the load and the ends of the

bridge from spreading out.

The materials such as stone and bricks are strong in compression but not in tension. Old arch

bridges are designed in such that nowhere in structure tension is developed.

iii. Truss bridge

Truss bridge also one of the oldest types of bridge. The truss is a simple skeletal structure. A

truss bridge is a bridge composed of connected elements (typically straight) which may be

stressed from tension, compression, or sometimes both in response to dynamic loads. It

contains of many small members but they together can support a large amount of weight and

span great distances. In most cases the design, fabrication, and erection of trusses is relatively

simple. Typical span length of a truss bridge is 40 500m.

iv. Cantilever bridge

The cantilever bridge consists of two spans projecting toward each other and joined at their

ends by a suspended simple span. The projecting spans are known as cantilever arms, and

these, plus the suspended span, constitute the main span. The cantilever arms also extend


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back to land, and this section is turn the another span. Trusses, plate girders, and box girders

can be built as cantilever bridges.

The chief advantages of the cantilever design are the saving in material and ease of erection of

the main span.

It can often be built out from the supports without blocking the channel below. Then the

suspended span can be lifted into place. The span can be greater than that of a simple beam,

because a beam can be added to the cantilever arms. As it as to oppose large tensile and

compressive forces and shear the structure will be massive thus increasing the weight. Truss

construction is used in the larger spans to reduce the weight.

v. Cable stayed bridges

A typical cable stayed bridge is a continuous girder with one or more towers erected above piers

in the middle of the span. These bridges are similar to suspension bridges in most respects

except for the way that the deck is hung from the support towers. Instead of long suspensioncables that extend from one end of the bridge to the other, large number of individual cables

extends directly from each tower to the deck.

vi. Suspension bridge

In this type of a bridge, the traffic carrying deck is supported by a series of wire ropes that

hang from massive cables drawn between tall towers. Any load applied to the bridge is

transformed into a tension in these main cable and they are anchored at each end of the bridge.

The deck is supported by vertical suspender cables or rods attached to main cables, called

hangers. Steel cables are extremely string but very flexible. Cables are very economical as theyallow a slender and lighter structure which is still able to span great distances. Many of the

components of a suspension bridge are made of steel. When steel is drawn (stretched) into

wires, its strength increases; consequently, a relatively flexible bundle of steel wires is stronger

than a solid steel bar of the same diameter. This is the reason steel cable is used to support

suspension bridges.

Important factors to be considered when designing the foundation of a bridge

Function of a foundation in bridge construction.

To keep the intensity of pressure within the safe limits of the bearing capacity


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To provide a leveled base for the construction of piers and abutments

To prevent the tilt and overturning of the piers and abutments

To avoid unequal settlement of the subsoil and super structure

The choice of type of the foundation depend primary on the followings factors.

Type of the bridge

Nature of the soil strata

Magnitude of the loads to be carried

Site conditions

Economy

Availability of construction techniques

Maximum likely scour depth

Types of foundation which are commonly used in bridge construction

1. Shallow foundation

Spread footing founded on rock or on suitable soil strata

2. Deep foundation

Pile foundation

Caisson foundation


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Some of world famous bridge construction

Fig Confederation Bridge in Canada


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Fig Golden Gate Bridge in America

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