IJCSIET-ISSUE5-VOLUME3-SERIES-2 Page 1 IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005 DESIGN OF CABLE – STAYED RAILWAY BRIDGE SARATH BABU J,ROLL NO:137K1D8716 M-TECH STRUCTURAL ENGINEERING DJR COLLEGE OF ENGINEERING &TECHNOLOGY UNDER THE GUIDENCE OF L.NAGARAJA (PH.D) ABSTRACT A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle. Designs of bridges vary depending on the function of the bridge, the nature of the terrain where the bridge is constructed; the material used to make it and the funds available to build it. Bridge building is a complex art and science and involves extensive knowledge, skill and expertise. It is engineering in itself. Among the various kinds of bridges existing cable –stayed bridges are found to be highly economical and have great aesthetic appeal. These are the preferred bridges for long spans in the recent days. Cable – stayed bridges are easy to construct and maintain. The history of bridges, bridge components and bridge terminology has been clearly discussed. General steps involved in any bridge construction are mentioned. A brief literature report of cable – stayed bridges is also presented. In this report we designed a cable – stayed railway bridge on River Gauthami between Yanam and Yedurlanka. The various survey data has been collected and thoroughly analyzed before proceeding to the design of the bridge. A drawing of the alignment is also shown in this report. The catchment area maps have been studied before determining the hydrographical particulars. The bridge is designed as per the IRS code for M BG two tracks. Two plate girders are used and truss shaped cross girders are placed at suitable spacing. Steel pylons and cables are designed to support the deck and transfer the forces effectively. The scour depth is calculated in order to calculate the depth of the pile foundation adopted. The bore – hole log and the soil characteristics at different depths are studied before determining the bearing capacity and type of foundation. A cost estimate is made considering the material costs as well as the construction costs. Finally the advantages of a cable – stayed bridge for longer spans over other kinds of bridges are discussed. It is found that cable – stayed bridges have the following advantages: 1) Greater stiffness than the suspension bridge, so that deformations of the deck under live loads are reduced. 2) Can be constructed by cantilevering out from the tower - the cables act both as temporary and permanent supports to the bridge deck. 3) It is very economical and has a huge aesthetic appeal especially if very long spans are involved. 1.1. INTRODUCTION Bridges are defined as structures, which provide a connection or passage over a gap without blocking the opening or passageway beneath. They can be over streams, canals and rivers, creeks and valleys or roads and railways passing beneath. These days‟ bridges are also being constructed over oceans to connect two or more islands. The structure can be for passage/ carriage
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IJCSIET-ISSUE5-VOLUME3-SERIES-2 Page 1
IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
DESIGN OF CABLE – STAYED
RAILWAY BRIDGE
SARATH BABU J,ROLL NO:137K1D8716
M-TECH STRUCTURAL ENGINEERING DJR COLLEGE OF ENGINEERING &TECHNOLOGY
UNDER THE GUIDENCE OF
L.NAGARAJA (PH.D)
ABSTRACT
A bridge is a structure built to span physical obstacles
such as a body of water, valley, or road, for the purpose
of providing passage over the obstacle. Designs of
bridges vary depending on the function of the bridge, the
nature of the terrain where the bridge is constructed; the
material used to make it and the funds available to build
it. Bridge building is a complex art and science and
involves extensive knowledge, skill and expertise. It is
engineering in itself. Among the various kinds of
bridges existing cable –stayed bridges are found to be
highly economical and have great aesthetic appeal. These
are the preferred bridges for long spans in the recent
days. Cable – stayed bridges are easy to construct and
maintain. The history of bridges, bridge components and
bridge terminology has been clearly discussed. General
steps involved in any bridge construction are mentioned.
A brief literature report of cable – stayed bridges is also
presented.
In this report we designed a cable – stayed railway
bridge on River Gauthami between Yanam and
Yedurlanka. The various survey data has been collected
and thoroughly analyzed before proceeding to the design
of the bridge. A drawing of the alignment is also shown
in this report. The catchment area maps have been
studied before determining the hydrographical
particulars. The bridge is designed as per the IRS code
for MBG two tracks. Two plate girders are used and truss
shaped cross girders are placed at suitable spacing. Steel
pylons and cables are designed to support the deck and
transfer the forces effectively. The scour depth is
calculated in order to calculate the depth of the pile
foundation adopted. The bore – hole log and the soil
characteristics at different depths are studied before
determining the bearing capacity and type of foundation.
A cost estimate is made considering the material costs as
well as the construction costs. Finally the advantages of a
cable – stayed bridge for longer spans over other kinds of
bridges are discussed.
It is found that cable – stayed bridges have the following
advantages:
1) Greater stiffness than the suspension bridge,
so that deformations of the deck under live
loads are reduced.
2) Can be constructed by cantilevering out from
the tower - the cables act both as temporary
and permanent supports to the bridge deck.
3) It is very economical and has a huge aesthetic
appeal especially if very long spans are
involved.
1.1. INTRODUCTION
Bridges are defined as structures, which provide a
connection or passage over a gap without blocking the
opening or passageway beneath. They can be over
streams, canals and rivers, creeks and valleys or roads
and railways passing beneath. These days‟ bridges are
also being constructed over oceans to connect two or
more islands. The structure can be for passage/ carriage
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of persons, cattle, vehicles, water or other materials
carried across in pipes or conveyers. Bridges are a civil
engineering creation that holds enormous appeal and
fascination to the people. Bridge building is as old as
civil engineering. The design of bridges depends on
various factors like function of the bridge, the nature of
the terrain where the bridge is constructed, the material
used to make it and the funds available to build it etc…
The concept of bridge building came into existence
with the felling of wooden logs across small streams due
to natural forces. With the growth of civilizations, the
need for travel impelled mankind to find ways and means
of bridging gaps over deep gorges and perennial streams,
for walking across. Owing to the above fact timber can
be considered as the earliest material to be used for
bridging. This has been followed by bridges built with
stone and then of brick, used by themselves or in
combination with timber. Such bridges however have
been possible only for short spans. But with the
development of steel and iron as construction materials
bridge engineering has also expanded its horizons to span
longer distances.
Design of a bridge is an art involving immense
knowledge, skill and experience. It is a highly tedious job
which requires through expertise in all branches of civil
engineering like surveying, transportation, structural
engineering, geotechnical engineering material science
etc… There are three dimensions involved in the
planning of huge structures which are designed for a
period of 50 to 100 years. They are:
1) Scientific dimension
2) Social dimension
3) Technological dimension
Scientific dimension implies that every structure has
to perform in accordance with laws of nature. These laws
of nature are interpreted by scientists as formulas
containing relationships between various basic elements,
and engineers make use of such pre – existing formulas
to design the structures. Though the method of analysis
may differ depending on the structure and practice the
ultimate concept of design remains the same. The
scientific dimension helps the engineer in evolving
efficient structures.
Bridges are built for improving the mobility of people
and enhancing the quality of life of the society. Such man
– made structures may have some adverse effects on the
environment. Therefore bridges should satisfy both the
immediate and future demands of mobility and also be
acceptable to people in terms of visibility, noise and
pollution during and after construction. As construction
of bridges is a public welfare program, the society has to
pay for the cost of the structure in the form of taxes and
tolls. These aspects form the social dimension of any
project.
Technological dimension deals with the major
technological developments in evolution in different
forms of structures, materials of construction, design and
construction techniques and also machinery and plants
used for construction. Technology played a vital role in
finding and refining a number of alternative materials for
use in bridge building, like bricks, cast iron, wrought
iron, steel, cement etc… Because of such technological
research and advances bridges of longer spans at
challenging locations have become possible. A
technological development in the design and manufacture
of vehicles has also led to a need to increase the strength
and geometrical requirements of the bridges being built
as well as their standards of maintenance.
However for a structural engineer, the scientific
dimension is of primary importance, but it is also
necessary to balance the other two dimensions before,
during and after construction of the structure. It is the
responsibility of a structural engineer to evolve a form of
structure which is socially acceptable and at the same
time results in an economic, durable and efficient
product. For this he/she has to make use of the
technological developments in an optimal manner.
Some of the famous bridges in the world are listed
below:
1) Golden Gate Bridge, San Francisco (Fig 1)
2) Millau Bridge, France
3) Tower Bridge, London
4) Akashi-Kaikyo Bridge, Japan (Fig 3)
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5) Sydney Harbor Bridge, Australia
6) Brooklyn Bridge, New York
7) Howrah Bridge, India (Fig 2)
8) Chapel Bridge, Switzerland
9) Godavari Bridge, India
10) Antioch Bridge, USA
11) Royal Victoria Dock Bridge, London
Fig. 1 Golden Gate Bridge, San Francisco Fig. 2
Howrah Bridge, Calcutta
Fig. 3 Akashi-Kaikyo Bridge, Japan
1.2. BASIC BRIDGE FORMS
There are six basic forms of bridge structures:
1) Beam bridges
2) Truss bridges
3) Arch bridges
4) Cantilever bridges
5) Suspension bridges
6) Cable stayed bridges
Beam bridges are horizontal beams supported at each end
by abutments, hence their structural name of simply
supported. A beam bridge carries vertical loads by
flexure.
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. The truss bridge of simple
span behaves like a beam because it carries vertical loads
by bending. The top chords are in compression, and the
bottom chords are in tension, while the vertical and
diagonal members are either in tension or compression
depending on their orientation.
Loads are carried primarily in compression by the
arch bridge, with the reactions at the supports (springing)
being both vertical and horizontal forces.
A cantilever bridge generally consists of three spans,
of which the outer spans, known as anchor spans, are
anchored down to the shore, and these cantilever over the
channel. A suspended span is rested at the ends of the
two cantilevers, and acts as a simply supported beam or
truss. The cantilevers carry their loads by tension in the
upper chords and compression in the lower chords.
A suspension bridge carries vertical loads from the
deck through curved cables in tension. These loads are
transferred to the ground through towers and through
anchorages.
In cable stayed bridge, the vertical loads on the deck
are carried by the nearly straight inclined cables which
are in tension. The towers transfer the cable forces to the
foundation through vertical compression. The tensile
forces in the stay cables induce horizontal compression in
the deck.
1.3. BRIDGE COMPONENTS
The main components of a bridge structure are:
1) Decking, consisting of deck slab, girders,
trusses, etc.;
2) Bearings for the decking;
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3) Abutments and piers;
4) Foundations for the abutments and the piers:
5) River training works, like revetment for
slopes for embankments at abutments, and
aprons at river bed level;
6) Approaches to the bridge to connect the
bridge proper to the roads on either side; and
7) Handrails, parapets and guard stones.
Some of the components of a typical bridge are shown in
the figure below:
Fig. 4 Components of a typical bridge
The components above the level of bearings are
grouped as superstructure, while the parts below the
bearing level are classed as substructure. The portion
below the bed level of a river bridge is called the
foundation. The components below the bearing and
above the foundation are often referred as substructure.
1.4. BRIDGE TERMINOLOGY
An important first step in understanding the
principles and processes of bridge construction is
learning basic bridge terminology. Although bridges vary
widely in material and design, there are many
components that are common to all bridges. In general,
these components may be classified either as parts of a
bridge superstructure or as parts of a bridge substructure.
Fig. 5 Parts of Bridge
SUPERSTRUCTURE
The superstructure consists of the components that
actually span the obstacle the bridge is intended to cross
and includes the following:
1) Bridge deck
2) Structural members
3) Parapets (bridge railings), handrails,
sidewalk, lighting and some drainage features
The top surface of a bridge which carries the traffic is
called deck. The deck is the roadway portion of a bridge,
including shoulders. Most bridge decks are constructed
as reinforced concrete slabs, but timber decks are
occasionally used in rural areas and open-grid steel decks
are used in some movable bridge designs (Bascule
Bridge). As polymers and fibre technologies are
improving in the recent days, Fibre Reinforced Polymer
(FRP) decks are also being used these days. Bridge decks
are required to conform to the grade of the approach
roadway so that there is no bump or dip as a vehicle
crosses onto or off of the bridge.
The most common causes of premature deck failure are:
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1) Insufficient concrete strength from an
improper mix design, too much water,
improper amounts of air entraining
admixtures, segregation, or improper curing.
2) Improper concrete placement, such as failure
to consolidate the mix as the concrete is
placed, pouring the concrete so slowly that
the concrete begins the initial set, or not
maintaining a placement rate in accordance.
3) Insufficient concrete cover due to improper
screed settings or incorrect installation of the
deck forms and/or reinforcement
A bridge deck is usually supported by structural
members. The most common types are:
1) Steel I-beams and girders
2) Pre - cast, pre - stressed, reinforced concrete
bulb T beams
3) Pre - cast, pre - stressed, reinforced concrete I
beams
4) Pre - cast, pre - stressed, concrete box beams
5) Reinforced concrete slabs
Fig. 6 Bridge Deck
Secondary members called diaphragms are used as
cross-braces between the main structural members and
are also part of the superstructure. Bracing that spans
between the main beams or girders of a bridge or viaduct
and assists in the distribution of loads is called
diaphragm.
Parapets (bridge railings); handrails, sidewalks,
lighting, and drainage features have little to do with the
structural strength of a bridge, but are important aesthetic
and safety items. The materials and workmanship that go
into the construction of these features require the same
inspection effort as any other phase of the work.
SUBSTRUCTURE
The substructure consists of all of the parts that support
the superstructure. The main components are:
1) Abutments or end-bents,
2) Piers or interior bents,
3) Footings
4) Piling.
Abutments support the extreme ends of the bridge and
confine the approach embankment, allowing the
embankment to be built up to grade with the planned
bridge deck. When a bridge is too long to be supported
by abutments alone, piers or interior bents are built to
provide intermediate support. Although the terms may be
used interchangeably, a pier generally is built as a solid
wall, while bents are usually built with columns.
The top part of abutments, piers, and bents is called
the cap. The structural members rest on raised, pedestal-
like areas on top of the cap called the bridge seats. The
devices that are used to connect the structural members
to the bridge seats are called shoes or bearings.
Abutments, bents, and piers are typically built on spread
footings. Spread footings are large blocks of reinforced
concrete that provide a solid base for the substructure and
anchor the substructure against lateral movements.
Footings also serve to transmit loads borne by the
substructure to the underlying foundation material.
When the soils beneath a footing are not capable of
supporting the weight of the structure above the soil,
bearing failure occurs. The foundation shifts or sinks
under the load, causing structure movement and damage.
In areas where bearing failure is likely, footings are built
on foundation piling. These load bearing members are
driven deep into the ground at footing locations to
stabilize the footing foundation. Piling transmits loads
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from the substructure units down to underlying layers of
soil or rock.
Fig. 7 Abutment Types
SPANS AND SPAN LENGTH
The terms bridge and span are used interchangeable;
however, to avoid confusion and misunderstanding,
Technicians and construction personnel draw a
distinction between the two.
A bridge is made up of one or more spans. A span is a
segment of a bridge that crosses from one substructure
unit to the next, from abutment to abutment, from
abutment to pier, from pier to pier, or from pier to
abutment. Span length refers to either the length of any
individual span within the structure or to the total bridge
length. In most cases, span lengths are considered as the
distance between centrelines of bearing from one
substructure unit to the next.
The three basic types of spans are shown below. Any of
these spans may be constructed using beams, girders or
trusses.
Simple Span: A span in which the effective length is the
same as the length of the spanning structure. The
spanning superstructure extends from one vertical
support, abutment or pier, to another, without crossing
over an intermediate support or creating a cantilever.
Continuous Span: A superstructure which extends as
one piece over multiple supports is called a continuous
span.
Cantilever Span: A cantilever span is a span which
projects beyond a supporting column or wall and is
counterbalanced and/or supported at only one end.
Fig. 8 Types of Spans
2. THERITICAL ASPECTS
2.1. HISTORY OF BRIDGES
The history of development of bridge construction is
closely linked with the history of human civilization. The
efficiency and sophistication of design and the ingenious
construction procedures kept pace with the advances in
science, materials and technology. Since ancient times,
bridges have been the most visible testimony to the
contribution of engineers. Bridges have always figured
prominently in human history . Nature fashioned the first
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bridges. The tree fallen accidentally across a stream was
the earliest example of a beam type bridge. Similarly, the
natural rock arch formed by erosion of the loose soil
below and the creepers hanging from tree to tree
allowing monkeys to cross from one bank to the other
were the earliest forebears of the arch and the suspension
bridges, respectively. The primitive man imitated nature
and learnt to build beam and suspension bridges.
The earliest reference to a man made bridge goes as far
as 3306 BC, an 1100 – m – long wooden bridge built in
England. The oldest bridge still standing is a stone slab
pedestrian bridge across river Meles in Smyrna, Turkey
said to be 2500 years old. Swiss were the pioneers of
timber bridges, specially using trestle form. In known
history, the Chinese appear to be the earliest to build
stone bridges. Romans are believed to have built bridges
and aqueducts for carriage of water before even the start
of the first millennium. Romans are also credited to have
used timber pile bents for foundation and piers as early as
95 BC. Queen Nitocrin built a bridge in stone piers and
wooden deck in about 780 BC. Iron and lead were used
in this bridge to bind the stones together. Gordon River
Bridge built in 13 BC in France was a masonry aqueduct
49 m high, with three rows of superposed arches.
Etruscans are believed to have used vaults for bridge
construction as early as 600 BC. Europe is considered to
be one of the birthplaces of bridge design and
technology. Therefore it may also be said that they must
have been the earliest to develop bridge building as a
technique.
Gradually the Roman Bridge building art spread to
Middle East as far as India. Macro Polo is said to have
remarked „Indian cultures adopted their own tools under
this influence for bridge building and further developed
suspension bridges‟. Indians have built suspension
bridges with use of ropes for suspension and bamboo and
timber planks for decks in the hilly regions from early
days. They are also credited to have built cantilever type
of bridges laying stone slabs one over the other in a
progressive manner to bridge gaps, but have kept no
records. Russians used timber as main bridge building
material until the end of 15th century. China has built
some notable bridges using tied arch form and cable
stayed bridges. Two elegant examples are Dagu Bridge at
Tianjin and a railway bridge at high altitude on their
recently opened rail link to Tibet.
In the medieval times church has greatly influenced
bridge building. All the bridges in this age have been
built with stone, brick masonry and timber using
empirical methods for design. A typical example is the
first London Bridge built by Peter of Colechurch in 1176
– 1209 AD. This was masonry with 19 pointed masonry
arches on piers, none of them with same dimensions.
Wittengen Bridge built in 1758 in Germany was the
longest timber bridge in Europe with a span of 119 m in
those days.
It was during Renaissance period that the concept of
bridge building based on scientific basis came into
existence. The truss system based on the principle of
triangles, which cannot be deformed, was developed.
Andrea Pallaido (1508 – 1580 AD), evolved several truss
forms, including the king post type. Verrazino (1615)
had written about roads, machines, water wheels, bridges
including masonry arches with use of pre - stressing rods,
as well as suspension bridges and the use of iron bars for
suspension bridges. First metal bridge was
Coalbrookdale Bridge built in cast iron in the year 1776.
James was the person who patented suspension bridge
form and built some with steel chains. French Engineer
Vicat invented the aerial spun cables for suspension. This
type has become the major form for building longer and
longer spans today.
The industrial revolution ushered in the use of iron in
bridges in place of stone and timber. The first iron bridge
was built at Coalbrookdale in 1779 over the Severn in
England by Abraham Darby and John Wilkinson. It
consisted of five semicircular arch ribs in cast iron,
joined together side by side to form a single arch span of
30 m. The construction details of Iron Bridge followed
the spirit of timber and masonry construction practices.
Wrought iron replaced cast iron in bridge construction
during the period 1880 – 90. Wrought iron was ductile,
malleable and strong in tension. In 1808, James Finley in
Pennsylvania patented a design for suspension bridge
with wrought iron chain cables and level floor. Wrought
iron chains were used for a suspension bridge built by
Thomas Telford across the Menai Straits in Wales in
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1826 with a record – breaking span of 177 m. The Menai
Straits Bridge was the world‟s first iron suspension
bridge for vehicles and also the world‟s first iron
suspension bridge over sea water. Japanese also built iron
bridges in the same period. The longest cable suspension
bridge, Akashi Kaikyo Bridge, with a record span of
1991 m was built by them. Germany was the first to
introduce the concept of cantilever construction in the
modern days and incremental launching of concrete
decks, as well as the modern form of cable stayed
bridges.
Though steel is said to have been known in China by 200
BC and in India by 500 BC, its widespread use
materialized only in the latter half of nineteenth century
after the discovery of the Bessemer process in 1856. Eads
Bridge at St. Louis was the first bridge to be built with
extensive use of steel, as early as 1874. Firth of Forth
Railway Bridge in Scotland followed suit, with use of
tubular steel sections for main girders and columns. This
design had been appreciated for the bold attempt made to
span such lengths and shaping the structure so as to
follow clearly the force lines and giving an elegant look
for a viewer. Trend in 18 th and 19 th centuries for longer
span bridges especially in USA tended towards cable
stayed suspension bridges. The Golden Gate Bridge in
San Francisco, built in 1973 is the most famous of this
type. Use of wrought iron and steel as basic materials
instead of masonry and timber has revolutionized bridge
building for many centuries till the arrival of pre -
stressed concrete. The first Portland cement concrete
bridge to be built was the Grand Maitre Aqueduct across
River Vane in France built in 1867 – 1874. France is also
the birthplace of pre - stressed concrete, which is the
major form of bridge superstructures all over the world
today either by itself or in combination with steel.
The world‟s first modern cantilever bridge was built in
1867 by Heinrich Gerber across the river Main at
Hassfurt, Germany, with a main span of 129 m. The
world‟s most famous cantilever bridge is the Firth of
Forth Bridge in Scotland. The world‟s longest span
cantilever bridge was built in 1917 at Quebec, over St.
Lawrence River, with a main span of 549 m. The first
attempt to construct this bridge ended in failure due to
miscalculation of the dead load and buckling of the web
plates of the structure was rebuilt. The Howrah Bridge
over the Hooghly River at Kolkata, built in 1943 with a
main span of 457 m, has elegant aesthetics and possesses
pleasing proportions among the suspended span,
cantilever arms and anchor spans. It was a notable
achievement at the time of construction. Developments in
welding technology and precision gas cutting techniques
in the post Second World War period facilitated the
economical fabrication of monolithic structural steel box
girders characterized by the use of thin stiffened plates
and the closed form of cross section.
Franklin D. Roosevelt once said „there can be little
doubt that in many ways the story of bridge building is
the story of civilization. By it, we can readily measure a
progress I each particular country‟. Based on this saying,
the Indian civilization being one of the oldest, must have
built bridges well before Christian era. According to
records of Chinese travelers on Indian history, India
appears to have had a number of bridges. Firoze Shah
who ruled in Delhi is said to have built canals and
bridges. One can still see some old masonry arch bridges
built by the Portuguese in 16th or 17 th century in Goa.
One old bridge still in use is the stone slab bridge across
River Cauvery at Srirangapatnam built by Tipu Sultan.
India also has a number of old masonry and stone arch
bridges built in the middle of the 19th century on the
Railways, which bear testimony to the skill of the local
people in bridge construction. The British who built the
railways have brought the steel bridge girders and their
designs form UK, but they depended on the local skills
and expertise to build the others. Structural forms and
designs for longer spans also appear to have come from
the British. The technical knowledge within the country
has since kept pace with the developments abroad. The
use of reinforced concrete for road bridges has become
popular in India since the beginning of the twentieth
century. The bridge types adopted include simply
supported slabs, simply supported T – beam span,
balanced cantilever with suspended spans, arch and bow
string girder and continuous or framed structures. The
Third Godavari Railway Bridge built in 1996 with 28
spans of 97.5 m is a recent example of elegant concrete
bowstring girder bridges.
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A number of cable stayed bridges have been built in
India in the past two decades, the major one being the
VidhyasagarSethu across Hooghly at Kolkata and the
Naini Bridge on River Jamuna at Allahabad. The
railways are building a number of major bridges
including a large steel arch bridge in Jammu and
Kashmir. The Border Roads Organization has erected a
cable stayed bridge using Bailey bridge girders in early
part of this millennium, which bridge is claimed to be
only bridge of the type at highest altitude in the world at
the time of construction.
Fig. 9 Millennium Bridge, London (Steel Suspension
Bridge)
Fig. 10 Godavari Bridge, India (Steel Arch Bridge)
2.2. CLASSIFICATION OF BRIDGES
Bridge may be classified into different types depending
on various factors as listed below:
Function: Based on the purpose for which a
bridge is constructed it may be classified as
follows
Foot
Road
Railway
Road – cum – rail
Pipe line
Water conveying
(aqueduct)
Jetty
Material: Based on the material used for
construction bridges may be divided into the
following type
Stone
Brick
Timber
Steel
Concrete
Composite
Aluminium
Fibre
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Form: Based on the form of the superstructure
bridges may be classified as
Beam
Arch
Truss
Suspension
Cable stayed
Cantilever
Type of support: Bridges are also classified
based on the type of the structure it is
supported with
Simply supported
Continuous
Cantilever
Position of floor/ deck: The deck plays an
important role in classification of bridges.
Deck
Through
Semi – through
Usage: The time period for which a particular
bridge is used also aids in division of bridges
into different types.
Temporary
Permanent
Service (Army)
With respect to water level: They are
classified as follows
Causeway
Submersible
High level (normal case)
Grade separators: The purpose of separation
classifies bridges as
Road – over
Road under (subway)
Flyover (road over road)
With respect to connections: The joints used
in the bridge greatly affect the functioning and
analysis of bridge and based on this they may
be classified as
Pin jointed
Riveted/ bolted
Welded
Temporary Bridges: There are also many
types of temporary bridges.
Pontoon
Bailey
Callender – Hamilton
Fig. 11 Through Type Bridge
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IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
Fig. 12 Simply Supported Bridge
Fig. 13 Temporary Bridge
2.3 CABLE STAYED BRIDGES
A cable stayed bridge is a bridge whose deck is
suspended by multiple cables that run down to the main
girder from one or more towers .The cable stayed bridge
is specially suited in the span range of 200 to 900 m and
thus provides a transition between the continuous box
girder bridge and the stiffened suspension bridge .It was
developed in Germany in the post war years in an effort
to save steel which was then in short supply. Since then
many cable stayed bridges have been built all over the
world, chiefly because they are economical over a wide
range of span lengths and they are aesthetically attractive
.The wide application of the cable stayed bridge has been
greatly facilitated in recent years by the availability of
high strength steels, the adoption of orthotropic decks
using advanced welding techniques and the use of
electronic computers in conjunction with rigorous
structural analysis of highly indeterminate structures. The
beauty and visibility of a cable stayed bridge at night can
be enhanced by innovative lighting schemes .The early
cable stayed bridges were mainly constructed using steel
for stay cables, Deck and towers. In some of the recent
constructions, the deck and towers have been constructed
in structural concrete or a combination of steel and
concrete.
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IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
The Stromsund Bridge in Sweden, built in 1957 with
a main span of 183 m, and the Dusseldorf North Bridge
built in 1958 with a span of 260 m are early examples of
cable – stayed bridges. Another well known bridge in
this category is the Maracaibo Lake Bridge in Venezuela
designed by Ricardo Morandi of Italy and built in 1963.
The Sunshine Skyway Bridge (1987) designed by
Eugene Figg and Jean Muller over Tampa Bay in Florida,
has a main span of 360 m with pre – stressed concrete
deck and single – plane cables. The Dames Pont Bridge
at Jacksonville, Florida, built in 1987 with a span of 390
m is the longest cable stayed bridge in USA. Designed by
Howard Needles and Finsterwalder, the bridge features H
– shaped Reinforced Concrete towers and two – plane
cables supporting R.C deck girders. Currently, the Tatara
Bridge in Japan (1999) with a span of 890 m is the
longest cable – stayed bridge in the world. The Millau
Viaduct, completed in 2005, with six spans of 350 m and
two spans of 240 m, supported on towers up to 235 m
height is a unique cable – stayed bridge.
India‟s first cable – stayed vehicular bridge is the
Akkar Bridge in Sikkim completed in 1988 with two
spans of 76.2 m each. The Second Hooghly Bridge
(VidyasagarSetu), completed in 1992, with a central span
of 457.2 m and two side spans of 182.9 m each, is a
notable engineering achievement in India. The various
cable – stayed bridges are shown in the following table.
Basic concepts of the application and design of the cable
stayed bridges are presented here.
Table 1. List of Cable – Stayed Bridges
The main components of a cable stayed bridge are:
1) Inclined Cables
2) Towers (also referred as pylons)
3) Deck
In a simple form, the cables provided above the deck
and connected to the towers would permit elimination of
intermediate piers facilitating a larger width for purposes
of navigation. When the number of stay cables in the
main span is between 2 and 6 the spans between the stay
supports tend to be large (between 30 and 60 m)
Year Bridge Location Main
Span
(m)
Deck
Material
1999 Tatara Kamiura,
Japan
890 Steel
1994 Normandie Seine,
France
856 Steel
2001 Nanjing – 2 Nanjing,
China
628 Steel
1993 Yangpu Shanghai,
China
602 Composite
1997 Maiko Chuo Nagoya,
Japan
590 Steel
1999 Oresund Sweden 490 Steel
1992 VidyasagarSetu Kolkata 457 Composite
1996 Second Severn Bristol,
UK
456 Composite
1987 Rama IX Bangkok 450 Steel
1983 Luna Spain 440 Concrete
1975 St. Nazaire France 404 Steel
1978 Stretto di
Rande
Vigo,
Spain
400 Steel
1982 Luling Mississippi 372 Steel
1978 Dusseldorf
Flehe
Germany 367 Steel
1987 Sunshine
Skyway
Florida,
USA
366 Concrete
1970 Duisburg
Neuekam
Germany 350 Steel
1990 Tempozan Japan 350 Steel
1990 Glebe Island Australia 345 Concrete
2004 Millau Viaduct Millau,
France
342 Steel
1974 West Gate Australia 336 Steel
1978 Zarate - Brazo Argentina 330 Steel
1993 Karnali Nepal 325 Composite
1972 Kohlbrand Germany 325 Steel
1969 Kniebrucke Germany 320 Steel
1977 Brotonne France 320 Concrete
1971 Erskine Scotland 305 Steel
1959 Severins Cologne 302 Steel
1987 Dongying China 288 Steel
1976 WadiKuf Beida,
Libya
282 Concrete
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IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
requiring large bending stiffness. The stay forces are
large and the anchorages of cables become complicated.
The erection of such bridges involves use of auxiliary
structures. On the other hand , the use of multiple stay
cables would facilitate smaller distances between points
of supports (between 6 and 10 m) for the deck girders ,
resulting in reduced structural depth and facilitating
erection by free cantilever method without auxiliary
supports .
The multiple stay cable system also permits easy
replacement of cables if needed and enhances
aerodynamics stability through increased damping
capacity. The deck can be supported by a number of
cables in a fan form (meeting in a bunch at the tower) or
in a harp form (joining at different levels on the tower) as
shown in the figure. The figure shows a typical fan-
shaped cable arrangement with the anchorages at the
tower distributed vertically down a certain length
(modified fan form). This arrangement facilitates easy
replacement of cables at a later date in case of accidents.
The fan type configuration results in minimum axial
force in deck girders. The harp form requires larger
quantity of steel for the cables. Includes the fan shape is
superior from a structural and economical view. The harp
shape possesses enhanced aesthetics. The harp
configuration cables also permits erection of the tower
and the deck to progress at the same time. Because of the
damping effect of inclined cables of varying lengths, the
cables stayed decks are less prone to wind –induced
oscillation than suspension bridges.
Fig. 14 Types of Cable Systems
Based on the span arrangement, the cable stayed bridge
can be one of four types:
1) Bridge with an eccentric tower, e.g. Hoescht
Bridge on main river
2) Symmetrical two – span bridge, e.g.
Ottmarshein Bridge in France
3) Three – span bridge, e.g. Brotonne Bridge,
France
4) Multi – span Bridge, e.g. Millau Viaduct,
France
TYPICAL CABLE STAYED BRIDGES
The first modern cable stayed bridge was the
Stromsund bridge in Sweden, built in 1956 with a main
span of 183m and two side span of 75m each .This
bridge consist of continuous plate girders supported by
two plane radial cables anchored to the tops of towers of
portal shape. The deck is of reinforced concrete slab
supported on strings and cross beams. The Dusseldorf
north bridge (1958) has harp type cables in two vertical
planes attached to single towers. The decking is of
orthotropic steel deck with box shaped main girders
stiffened by cross beams. The bridge has spans of 108-
260-108 m. The Severins Bridge (1959) in cologne has a
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IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
single A-frame tower with fan type cables, converging at
the apex of the A- frame. The decking is of orthotropic
steel deck with two main girders of box section as in fig.
The Norderelbe Bridge (1962) in Hamburg was the first
bridge with cables arranged in star type in single plane.
The bridge has a box section at centre with one single
web girder on either side as in fig. The cable
configuration is justified more from aesthetic
considerations than on economic grounds. The Brotonne
Bridge built in 1977 with a main span of 320 m has a
single plane of cable stays and uses a precast pre -
stressed concrete box girder deck. The Yangpu Bridge in
Shanghai, china built in 1994 with a main span of 620 m
marked a significant development. This was surpassed in
the same year by the Normandie Bridge in France with a
main span of 856 m. The Sunniberg Bridge in
Switzerland built in 1999 with main spans of 140 m and
the Millau viaduct in France completed in 2005 with
main spans of 342 m are outstanding applications of
multi-span cable stayed bridges.
Akkar Bridge (2 spans of 79.0 m) and Hardwar bridge (2
spans of 65.0 m) are early examples of Indian cable
stayed bridges, essentially evolved as forerunners for
longer spans to follow .The second Hooghly bridge
(Vidyasagarsethu) completed in 1992 with a main span
of 457 m and side spans of 182.9 m each, using fan type
cable arrangement, is a land mark of bridge construction
in India. The Tatara Bridge on the Onomichi –Lmabari
highway route of the Honshu-shikoku bridge project in
Japan is the longest span cable stayed bridge in the world
with a main span of 890 m. The steel towers are 176 m
high above the bridge deck, corresponding to 0.2 of the
main span. The towers are shaped like an inverted Y after
examining the wind resistance, structural efficiency and
aesthetics. The stay cables have two-plane multi-fan
shape. The cables are anchored at spacing of 20 m at
deck level and at 3 m spacing at the tower. Based on
wind tunnel tests, the surface of the polyethylene cover
of the stay cables was provided with indentations, with a
view to prevent the turbulence that results from wind
blowing on rain water running on the surface of the long
stay cables. This innovation provides sufficient damping
and avoids the need for ties between the cables. The deck
is of streamlined steel box girder. The deck width is 28.1
m corresponding to width-to-span ratio of 1:31.7. The
center span was erected by the cantilever method. The
aesthetic appeal, the economic advantage and the ease of
construction make the cable stayed bridge the preferred
option in the span range of 200 to 900 m.
Fig. 15 Tatara Bridge, Japan
Fig. 16 Millau Viaduct Bridge, France
ARRANGEMENT OF CABLES
The cables may be arranged in one central plane (axial
suspension) as in Norderelbe bridge, in two vertical
planes with twin-leg tower as in Stromsund or
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IJCSIET--International Journal of Computer Science inf ormation and Engg., Technologies ISSN 2277-4408 || 01102015-005
Dusseldorf North bridges, or in two inclined planes as in