Unit 1 BRIDGE TYPES

Authors: Do Viet Hai – Phan Hoang Nam Unit 1: BRIDGE TYPES A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providin

Authors: Do Viet Hai – Phan Hoang Nam

Unit 1: BRIDGE TYPES

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

There are six main types of bridges: beam bridges, truss bridges, arch bridges, cantilever bridges, suspension bridges and cable-stayed bridges

Beam bridges

Beam bridges are horizontal beams supported at

each end by abutments, hence their structural name

of simply supported When there is more than one

span the intermediate supports are known as piers The earliest beam bridges were simple logs that sat across streams and similar simple structures In modern times, beam bridges are large box steel girder bridges Weight on top of the beam pushes straight down on the abutments at either end of the bridge They are made up mostly

of wood or metal Beam bridges typically do not exceed 76 m long The world's longest beam bridge is Lake Pontchartrain Causeway in southern Louisiana in the United States, at 38.35 km, with individual spans of 17 m

Truss bridges

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 Truss bridges are one of the oldest types of modern bridges The basic types of truss bridges shown in this article have simple designs which could be easily analyzed by nineteenth and early twentieth century engineers

A truss bridge is economical to construct owing to its efficient use of materials

Authors: Do Viet Hai – Phan Hoang Nam

Arch bridges

Arch bridges have abutments at each end The

earliest known arch bridges were built by the

Greeks, and include the Arkadiko Bridge The

weight of the bridge is thrust into the abutments at either side Dubai in the United Arab Emirates is currently building the Sheikh Rashid bin Saeed Crossing, which is scheduled for completion in 2012 When completed, it will be the largest arch bridge in the world

Cantilever bridges

Cantilever bridges are built using cantilevers—

horizontal beams supported on only one end Most

cantilever bridges use a pair of continuous spans that

extend from opposite sides of the supporting piers to meet at the center of the obstacle the bridge crosses Cantilever bridges are constructed using much the same materials & techniques as beam bridges The difference comes in the action of the forces through the bridge The largest cantilever bridge is the 549 m Quebec Bridge

in Quebec, Canada

Suspension bridges

Suspension bridges are suspended from cables The

earliest suspension bridges were made of ropes or

vines covered with pieces of bamboo In modern

bridges, the cables hang from towers that are attached to caissons or cofferdams The caissons or cofferdams are implanted deep into the floor of a lake or river The longest suspension bridge in the world is the 3,909 m Akashi Kaikyo Bridge in Japan

Cable-stayed bridges

Cable-stayed bridges, like suspension bridges, are

held up by cables However, in a cable-stayed

bridge, less cable is required and the towers holding

Authors: Do Viet Hai – Phan Hoang Nam

the cables are proportionately shorter The first known cable-stayed bridge was designed in 1784 by C.T Loescher The longest cable-stayed bridge is the Sutong Bridge over the Yangtze River in China

By use

A bridge is designed for trains, pedestrian or road traffic, a pipeline or waterway for water transport or barge traffic An aqueduct is a bridge that carries water, resembling a viaduct, which is a bridge that connects points of equal height A road-rail bridge carries both road and road-rail traffic

Bridges are subject to unplanned uses as well The areas underneath some bridges have become makeshift shelters and homes to homeless people, and the undersides

of bridges all around the world are spots of prevalent graffiti Some bridges attract people attempting suicide, and become known as suicide bridges

To create a beautiful image, some bridges are built much taller than necessary This type, often found in east-Asian style gardens, is called a Moon bridge, evoking a rising full moon Other garden bridges may cross only a dry bed of stream washed pebbles, intended only to convey an impression of a stream Often in palaces a bridge will be built over an artificial waterway as symbolic of a passage to an important place or state of mind A set of five bridges cross a sinuous waterway in

an important courtyard of the Forbidden City in Beijing, the People's Republic of China The central bridge was reserved exclusively for the use of the Emperor, Empress, and their attendants

(Source: Wikipedia)

Authors: Do Viet Hai – Phan Hoang Nam

Match the words in column A with their meanings in column B

1 Beam bridge a In theory, the individual parts of this structure only

subject to tension and compression forces but not bending forces

2 Truss bridge b The second oldest bridge type This structure doesn’t

require piers in the center and uses a curved structure

3 Arch bridge c The support is in the middle of a span, not the end

4 Cantilever bridge d This structure is a continuous girder with one or more

towers erected above piers in the middle of the span

5 Suspension bridge e This structure often uses I-beams or box girders in their

construction

6 Cable-stayed bridge f This structure allows for the longest spans

Word Pronounced

beam biːm

truss trʌs

arch ɑːtʃ

cantilever ˈkæntɪliːvə(r)

suspension səˈspenʃn

cable-stayed ˈkeɪbl-steɪ

Authors: Do Viet Hai – Phan Hoang Nam

Vocabulary

Word Pronounced Meaning

span spæn the part of a bridge or an arch between one

vertical support and another

obstacle ˈɒbstəkl an object that is in your way and that makes it

difficult for you to move forward

terrain təˈreɪn used to refer to an area of land when you are

mentioning its natural features

material məˈtɪəriəl a substance that things can be made from

fund fʌnd money that is available to be spent

abutment əˈbʌtmənt a masonry mass supporting and receiving the

thrust of part of an arch or vault

stream striːm a continuous flow of liquid or gas

box steel girder bɒks stiːl ˈɡɜːrdər

element ˈelɪmənt a necessary or typical part of something

tension ˈtenʃn the state of being stretched tight

compression kəmˈpreʃn an increase in pressure of the charge in an

engine or compressor obtained by reducing its volume

dynamic load daɪˈnæmɪk ləʊd a force exerted by a moving body on a

resisting member, usually in a relatively short time interval

thrust θrʌst to push something/somebody suddenly or

violently in a particular direction

schedule ˈʃedjuːl a plan that lists all the work that you have to

do and when you must do each thing

continuous span kənˈtɪnjuəs spæn a span which is formed of a series of

consecutive spans (over three or more supports) that are continuously or rigidly connected so that bending moment may be transmitted from one span to the adjacent ones

pier pɪə(r) a large strong piece of wood, metal or stone

that is used to support a roof, wall, bridge, etc

Authors: Do Viet Hai – Phan Hoang Nam

suspend səˈspend to hang something from something else

cable ˈkeɪbl a set of wires, covered in plastic or rubber,

that carries electricity, telephone signals, etc

caisson kəˈsuːn a watertight chamber open at the bottom and

containing air under pressure, used to carry out construction work under water

cofferdam ˈkɒfəˌdæm a watertight structure, usually of sheet piling,

that encloses an area under water, pumped dry

to enable construction work to be carried out

tower ˈtaʊə(r) a tall narrow building or part of a building,

especially of a church or castle

train treɪn a railway/railroad engine pulling a number of

coaches/cars or trucks, taking people and goods from one place to another

pedestrian pəˈdestriən a person walking in the street and not

travelling in a vehicle

road traffic rəʊd ˈtræfɪk a hard surface built for vehicles to travel on

pipeline ˈpaɪplaɪn a series of pipes that are usually underground

and are used for carrying oil, gas, etc over long distances

waterway ˈwɔːtəweɪ a river, canal, etc along which boats can

travel

water transport ˈwɔːtə(r) ˈtrænspɔːt

barge bɑːdʒ a large boat with a flat bottom, used for

carrying goods and people on canals and rivers

aqueduct ˈækwɪdʌkt a structure for carrying water, usually one

built like a bridge across a valley or low ground

road-rail bridge rəʊd-reɪl brɪdʒ

makeshift shelter ˈmeɪkʃɪft ˈʃeltə(r) used temporarily for a particular purpose

because the real thing is not available

prevalent graffiti ˈprevələnt ɡrəˈfiːti

Authors: Do Viet Hai – Phan Hoang Nam

suicide ˈsuːɪsaɪd the act of killing yourself deliberately

dry bed draɪ bed

convey kənˈveɪ to make ideas, feelings, etc known to

somebody

pebble ˈpebl a smooth, round stone that is found in or near

water

artificial ˌɑːtɪˈfɪʃl made or produced to copy something natural;

not real

exclusively ɪkˈskluːsɪvli only given to one particular person or group

attendant əˈtendənt a person whose job is to serve or help people

in a public place

Authors: Do Viet Hai – Phan Hoang Nam

Further reading

Golden Gate Bridge

The Golden Gate Bridge is a

suspension bridge spanning the

Golden Gate, the opening of the San

Francisco Bay into the Pacific

Ocean As part of both U.S Route

101 and California State Route 1, the

structure links the city of San

Francisco on the northern tip of the

San Francisco Peninsula to Marin

County The Golden Gate Bridge was the longest suspension bridge span in the world when it was completed in 1937, and has become one of the most internationally recognized symbols of San Francisco, California, and of the United States Despite its span length being surpassed by eight other bridges since its completion, it still has the second longest suspension bridge main span in the United States, after the Verrazano-Narrows Bridge in New York City It has been declared one of the modern Wonders of the World by the American Society of Civil Engineers The Frommers travel guide considers the Golden Gate Bridge "possibly the most beautiful, certainly the most photographed, bridge in the world"

(Source: Wikipedia)

Authors: Do Viet Hai – Phan Hoang Nam

Sutong Yangtze River Bridge

The Sutong Yangtze River Bridge

is a cable-stayed bridge that spans

the Yangtze River in China between

Nantong and Changshu, a satellite

city of Suzhou, in Jiangsu province

With a span of 1,088 metres

(3,570 ft), it is the cable-stayed

bridge with the longest main span in

the world as of 2011 Its two side

spans are 300 metres (980 ft) each, and there are also four small cable spans The bridge received the 2010 Outstanding Civil Engineering Achievement award (OCEA) from the American Society of Civil Engineers

Two towers of the bridge are 306 metres (1,004 ft) high and thus the second tallest

in the world The total bridge length is 8,206 metres (26,923 ft) Construction began in June 2003, and the bridge was linked up in June 2007 The bridge was opened to traffic on 25 May 2008 and was officially opened on 30 June 2008 Construction has been estimated to cost about US$1.7 billion

The completion of the bridge makes the commute between Shanghai and Nantong, previously a four-hour ferry ride, shorten to about an hour It brings Nantong one step closer to becoming an important part of the Yangtze River Delta economic zone, and has further attracted foreign investors into the city The bridge is also pivotal in the development of poorer northern Jiangsu regions

(Source: Wikipedia)