The document discusses different types of bridges including beam, truss, arch, suspension, cantilever, and cable-stayed bridges. It then focuses on suspension bridges, providing details on their construction and notable examples like the Akashi Kaikyo Bridge in Japan, which has the world's largest suspension bridge main span at 1,991 meters. Cable-stayed bridges are also examined, comparing their construction and forces to suspension bridges. The Russky Bridge in Russia is given as an example of a long cable-stayed bridge type.

1. Damascus University
Faculty Of Civil Engineering
Structural Engineering
Suspension Bridges
VS
Cable-Stayed Bridges
Written By : Hussein Hasan
Supervised By : Prof. Eng. Mouaid Soubh

2. 2
Abstract
‫إن‬‫انهدف‬‫هى‬ ‫اندزاست‬ ‫هري‬ ‫مه‬‫امل‬‫اقرزوت‬‫بني‬ ‫مر‬‫املعهاقت‬ ‫انجسىز‬‫ونكه‬ , ‫برنكىابم‬ ‫املدعىمت‬ ‫وانجسىز‬
‫انجسىز‬ ً‫وه‬ ‫اإلوشرئٍت‬ ‫انجمهت‬ ‫بحسب‬ ‫انجسىز‬ ‫أوىاع‬ ‫استعساض‬ ‫تم‬ ‫بداٌت‬‫انجرئزٌت‬‫وانجسىز‬
( ‫انجمرنىوٍت‬‫انشبكٍت‬ ‫انجىائز‬ ‫ذاث‬)‫و‬‫انجسىز‬‫اناقىسٍت‬‫انظفسٌت‬ ‫وانجسىز‬‫اوتاقهىر‬ ‫ثم‬‫محىز‬ ‫إىل‬
‫دزاستىر‬‫املعهاقت‬ ‫انجسىز‬ ‫عه‬ ‫انىايف‬ ‫انشسح‬ ‫وهى‬‫امل‬ ‫وانجسىز‬‫و‬ ‫برنكىابم‬ ‫شدودة‬‫عه‬ ‫انتحسي‬‫مٍزاث‬
‫ومسروئ‬‫م‬ ‫كم‬‫ىهر‬,‫ج‬ ‫أهم‬ ‫بدزاست‬ ‫قمىر‬ ‫املعهاقت‬ ‫انجسىز‬ ‫عه‬ ‫وكمثرل‬‫انعرنم‬ ‫يف‬ ‫سس‬) ‫اَن‬ ‫(حتى‬
‫انىىع‬ ‫هرا‬ ‫مه‬ ‫ٌصىف‬‫جسس‬ ‫وهى‬(Akashi Kaikyo)‫انٍربرن‬ ‫يف‬‫نهجسىز‬ ‫برنىسبت‬ ‫األمس‬ ‫وكرنك‬
( ‫جسس‬ ‫وهى‬ ‫انىىع‬ ‫هرا‬ ‫مه‬ ‫انعرنم‬ ‫يف‬ ‫األطىل‬ ‫انجسس‬ ‫هىر‬ ‫واملثرل‬ ‫برنكىابم‬ ‫املدعىمت‬Russky
Bridge‫زوسٍر‬ ‫يف‬ ).

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Contents
I Structural Types Of Bridges 4
Beam Bridges 4
Truss Bridges 5
Arch Bridges 6
Suspension Bridges 7
Cantilever Bridges 8
Cable-stayed bridges 9
II Suspension Bridges 10
World’s Longest-Span Suspension Bridges 12
Advantages and Disadvantages of Suspension Bridge 13
Example : Akashi Kaikyo Bridge 14
III Cable-Stayed Bridges 15
Construction Of Cable-Stayed Bridges 17
Example : Russky Bridge 18
((Resources)) 19

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Structural Types Of Bridges
 Beam Bridges
Beam bridges are the oldest and simplest bridge design consisting of vertical piers and
horizontal beams - e.g. just a simple plank or stone slab. They are suitable only for short spans
but can used for larger crossings by adding additional piers.
Forces: As the bridge is loaded, by traffic for example, the beam bends which causes the top
surface to be compressed and the bottom surface to be stretched or put in tension.
Advantages: they are easy to build and inexpensive relative to other bridge types so are very
common.
Disadvantages: they have a limited span and do not allow large boats or vehicles to pass
underneath.

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 Truss Bridges
Truss Bridges are structures built up by jointing together lengths of material to form an open
framework - based mainly on triangles because of their rigidity. They are very strong and can
support heavy loads.
Forces: As with a Beam Bridge the top of a loaded truss is placed in compression and bottom
in tension. These forces are shared among the angled members.
Advantages: They are very strong and make efficient use of materials
Disadvantages: They are more complex to construct and need a high level of maintenance.

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 Arch Bridges
Arch bridges were built by the Romans and have been in use ever since. They are often
chosen for their strength and appearance.
Forces: the compressive forces created by the load are transferred down through the arch and
resisted by the supports, or abutments, at its base. Abutment support prevents the arch
spreading under load.
Advantages: they are very strong and can be built from a wide range of materials
Disadvantages: limited spans unless multiple arches (or viaducts) are used and
uneconomical use of materials.

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 Suspension Bridges
Suspension bridges main elements are a pair of main suspension cables stretching over two
towers and attached at each end to an anchor buried deep in the ground. Smaller vertical
suspender cables are attached to the main cables to support the deck below.
Forces: any load applied to the bridge is transformed into a tension in the main cables which
have to be firmly anchored to resist it.
Advantages: strong and can span long distances such as across rivers
Disadvantages: expensive and complex to build.

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 Cantilever Bridges
Cantilever bridges are based on structures that project horizontally into space, supported at
only one end - like a spring board.
Forces: if two cantilevers project out from a central pier the forces are balanced.
Advantages: more easily constructed at difficult crossings by virtue of using little or no false
work.
Disadvantages: complex structures and can be difficult to maintain.

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 Cable-Stayed Bridges
Cable-stayed bridges may appear to be similar to suspension bridges, but in fact they are
quite different in principle and in their construction. There are two major classes of cable-
stayed bridges: Fan type, which are the most efficient, and Harp or parallel type, which allow
more space for the fixings.
Forces: As traffic pushes down on the roadway, the cables, to which the roadway is attached,
transfer the load to the towers, putting them in compression. Tension is constantly acting on
the cables, which are stretched because they are attached to the roadway.
Advantages: good for medium spans, greater stiffness than the suspension bridge, can be
constructed by cantilevering out from the tower, horizontal forces balance so large ground
anchorages are not required.
Disadvantages: typically more expensive than other types of bridge, except suspension
bridges .

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Suspension Bridges
Suspension bridge, bridge with overhead cables supporting its roadway. One of
the oldest of engineering forms, suspension bridges were constructed by
primitive peoples using vines for cables and mounting the roadway directly on the
cables. A much stronger type was introduced in India about the 4th century AD
that used cables of plaited bamboo and later of iron chain, with the roadway
suspended.
In modern times, the suspension bridge provided an economical solution to the
problem of long spans over navigable streams or at other sites where it is difficult
to found piers in the stream. British, French, American, and other engineers of
the late 18th and early 19th centuries encountered serious problems of stability
and strength against wind forces and heavy loads; failures resulted from storms,
heavy snows, and droves of cattle. Credit for solving the problem belongs
principally to John Augustus Roebling, a German-born American engineer who
added a web truss to either side of his roadways and produced a structure so
rigid that he successfully bridged the Niagara Gorge at Niagara Falls, New York,
the Ohio River at Cincinnati, and, finally, in his masterpiece, the East River
between Brooklyn and Manhattan at New York City.

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The technique of cable spinning for suspension bridges was invented by the
French engineer Louis Vicat, a contemporary of Roebling. Vicat’s method
employed a traveling wheel to carry the continuous cable strand from the
anchorage on one side up over the tower, down on a predetermined sag
(catenary) to the midpoint of the bridge, up and over the tower on the farther side
to the farther anchorage, where a crew received the wheel, anchored the strand,
and returned the wheel, laying a fresh strand. From these successive parallel
strands a cable was built up.
Another major development in the modern suspension bridge was the pneumatic
caisson, which permitted pier foundation at great depths. It was used initially by
French, British, and American engineers, including Washington Roebling, who
completed his father’s Brooklyn Bridge.
For a time in the 1930s, American engineers experimented with a narrow solid
girder in place of the web truss to stiffen the roadway, but the failure of the
Tacoma Narrows Bridge in 1940 under aerodynamic forces instigated a return to
the web truss. Later, aerodynamically stable box girders replaced the web truss.
By the late 1980s, three suspension bridges (the Golden Gate, in San Francisco,
the Verrazano-Narrows, in New York City, and the Humber Bridge, near Hull,
England) had main-span lengths of more than 4,000 feet (1,200 meters). Modern
steel alloys are considered capable of much greater spans. Though suspension
bridges can be made strong enough to support freight trains, they have nearly all
been designed for automobile traffic.
A cable-braced bridge was developed by German engineers at Cologne,
Düsseldorf, and elsewhere in the 1950s and ’60s; in this form a single tower at
the midpoint supports the roadway by means of a number of cables. Another
development of the 1960s, aimed at reducing time of construction, was cable
fabricated in the shop.

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Advantages and Disadvantages of Suspension Bridge
 Economic Advantage
The area spanned by a suspension bridge is very long in proportion to the amount
of materials required to construct bridges.
 Height Advantage
Built over waterways, suspension bridges can be built high, allowing the passage of
tall ships unhindered by the bridge. The Golden Gate bridge has a clearance of 220
feet over the waters of San Francisco Bay at high tide.
 Construction Advantage
During construction, temporary central supports do not need to be built, and access
to the construction is not required from beneath. This means busy roadways and
waterways do not need to be disrupted.
 Flexibility Advantages/Disadvantages
Suspension bridges are flexible, which is an advantage until conditions become
severe. Instability in extremely turbulent conditions or during strong earthquakes
may require temporary closure. In 1940, high winds caused the Tacoma Narrows
bridge, near Seattle, Washington, to collapse.
 Foundation Disadvantages
When built in soft ground, suspension bridges require extensive and expensive
foundation work to combat the effects of the heavy load on foundation towers.
 Heavy Loads
Flexibility also becomes a disadvantage when heavy, concentrated loads are
involved. Suspension bridges are not generally used for regional rail crossings that
carry maximum weight loads, which adds dangerous stress to the structure.

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Akashi Kaikyo Bridge
Akashi Kaikyo Bridge is the world’s
largest suspension bridge with a main
span of 1,991 meters . The bridge spans
the Akashi Strait , between Kobe and
Awaji - shima in Japan. Akashi Strait is a
known fishing spot and there are about
1,300 boats spacewalks strait daily.
The building of the bridge began in 1988
and in 1998 the bridge finished. During
construction vari 1995 there was one
earthquake in Kobe area. When shifted
the foundations of the towers so that the
main span was increased by 0.8 m
Akashi Kaikyo Bridge is designed to
withstand earthquakes of up to 8.5 on
the Richter scale and speed of 80
meters per second. The main cable has
a diameter of 1122 mm and consists of
36,830 small wires of 5.23 mm in
diameter. The main cable has a dry air system to protect the main cable from
corrosion. The system provides dry air into the cables so that the humidity inside
the cables remain constant. Akashi Kaikyo Bridge is lighting with 1737 lamps,
lamps that are on the main cable changing colors. Next to the bridge is a
wonderful bridge museum.
Akashi Kaikyo Bridge
Design Suspension bridge
Total length 3,911 metres ( 2.430 mi)
Height 282.8 metres (928 ft) (pylons)
Longest span 1,991 metres (1.237 mi)
Clearance below 65.72 metres (215.6 ft)
Designer Satoshi Kashima
Construction begin 1988
Construction end 1998
Opened April 5, 1998

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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. From these towers, cables stretch
down diagonally (usually to both sides) and support the girder.
Steel cables are extremely strong but very flexible. Cables are very economical
as they allow a slender and lighter structure which is still able to span great
distances. Though only a few cables are strong enough to support the entire
bridge, their flexibility makes them weak to a force we rarely consider: the wind.
For longer span cable-stayed bridges, careful studies must be made to
guarantee the stability of the cables and the bridge in the wind.
The lighter weight of the bridge, though a disadvantage in a heavy
wind, is an advantage during an earthquake. However, should
uneven settling of the foundations occur during an earthquake or over
time, the cable-stayed bridge can suffer damage so care must be
taken in planning the foundations. The modern yet simple
appearance of the cable-stayed bridge makes it an attractive and
distinct landmark.
The unique properties of cables, and the structure as a whole, make the design
of the bridge a very complex task. For longer spans where winds and
temperatures must be considered, the calculations are extremely complex and
would be virtually impossible without the aid of computers and computer
analysis. The fabrication of cable stay bridges is also relatively difficult. The cable

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routing and attachments for the girders and towers are complex structures
requiring precision fabrication.
There are no distinct classifications for
cable-stayed bridges. However, they can
distinguished by the number of spans,
number of towers, girder type, number of
cables, etc. There are many variations in
the number and type of towers, as well as the number and arrangement of
cables. Typical towers used are single, double, portal, or even A-shaped towers.
Cable arrangements also vary greatly. Some typical varieties are mono, harp,
fan, and star arrangements . In some cases,
only the cables on one side of the tower are
attached to the girder, the other side being
anchored to a foundation or other
counterweight.

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 Construction Of Cable-Stayed Bridges
Construction of cable-stayed bridges usually follows the cantilever method. After
the tower is built, one cable and a section of the deck are constructed in each
direction. Each section of the deck is pre-stressed before continuing. The
process is repeated until the deck sections meet in the middle, where they are
connected. The ends are anchored at the abutments.

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Russky Bridge
The Russky Bridge (Russian:
Русский мост – Russian Bridge) is a
bridge built across the Eastern
Bosphorus strait, to serve the Asia-
Pacific Economic Cooperation
conference that took place in
Vladivostok in 2012. The bridge
connects the mainland part of the city
(Nazimov peninsula) with Russky
Island, where the main activities of
the summit took place. The bridge
was completed in July 2012 and
opened by Russian Prime Minister
Dmitry Medvedev. On September 3,
2012, the bridge was officially given
its name.
Russky Bridge
Design Cable-Stayed bridge
Total length 3,100 meters (10,200 ft)
Height 320.9 meters (1,053 ft)
Width 29.5 meters (97 ft)
Longest span 1,104 meters (3,622 ft)
Clearance below 70 m
Opened July 2012

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Resources
http://www.britannica.com/technology/bridge-engineering
http://www.historyofbridges.com/facts-about-bridges/types-of-bridges/
https://en.wikipedia.org/wiki/Bridge
https://en.wikipedia.org/wiki/Akashi_Kaiky%C5%8D_Bridge
https://en.wikipedia.org/wiki/Russky_Bridge
http://www.dtonline.org/vle/mod/lesson/view.php?id=276
http://pghbridges.com/basics.htm