Bridge magazine jan15

JANUARY 2015

An e-twinning 2015 project by Makrochori Highschool,Imathia, Greece

By Bill Anastos,Vassilis Mouratidis, Ioanna Polychroniadou, Polychronis Polychroniadis Coordination/Editing: Zarifi Vassoglou

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A bridge is a structure built to span physical obstacles, such as body of water, valley or road for the purpose of providing passage over the obstacle. All major bridges are built with the public’s money. Therefore, bridge design that best serves the public’s interest has a threefold goal: to be as efficient, as economical and as elegant as is safely possible.

The first bridges were made by nature itself –as simple as a beam fallen across a stream or stones in a river.

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The first bridges made by humans were probably spans of cut wooden logs or planks and eventually stones, using a simple support and crossbeam arrangement.

Theogefyro,(Godmade bridge), Greece,allenaki.wordpress,com.

BASIC FORMS There are six basic bridge forms: the beam, the truss, the cantilever, the arch, the suspension and the cable-stay.

BEAM BRIDGES

When a bridge is made up of beams spanning between only two supports, it is called a simply supported beam bridge. If two or more beams are joined rigidly together over supports, the bridge Vasco-da-Gama beam bridge www.golisbom.com

becomes continuous. In

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modern times, beam bridges can range from small wooden beams to large steel boxes. They are typically made from steel, concrete or wood, they are simple to construct and ideal for short distances.

TRUSS BRIDGES A truss

Britannia bridge, flickr.com

bridge is a bridge whose load- bearing superstructure is composed of a truss. This is a structure of connected elements forming triangular units.

Truss bridges are one of the oldest type of modern bridges. Trusses are popular because they use a relatively small amount of material to carry relatively large loads, yet they are strong and fairly light.

CANTILEVER BRIDGES Cantilever bridges are built using cantilevers –horizontal beams supported on only one end. A cantilever bridge is generally made with three spans, of which the outer spans are both anchored down at the shore and cantilever out over the channel to be crossed. The central span rests on the cantilevered arms extending from the outer spans.

Forth (cantilever rail) bridge,Scotland,panoramio.com

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ARCH BRIDGES Arch bridges have abutments at each end. The weight of the bridge is thrust into the abutment at either side.

The earliest known arch bridges were built by the Greeks. The greatest bridge builders of antiquity, though, are thought to be the Romans. They built magnificent arch bridges and aqueducts, some of which still stand today.

The arch shape allows this bridge to support itself without the use of beams or piers. Other advantades include the ability to deal with bending forces and Alcantara arch bridge, panoramio,com.

the simplicity of materials.

SUSPENSION BRIDGES

panoramio.com

Suspension bridges are suspended by cables. The earliest suspension bridges were made of ropes and vines. In modern bridges the cables hang from towers that are attached to caissons or cofferdams, which are implanted deep in the floor of a lake or river. Among the

advantages of these bridges is their flexibity and ttheir suitability

to

cover

long

distances (longer than any other type).

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The Humber (suspension) bridge, England,natlagdon,com.

CABLE STAYED BRIDGES Assut del’or, Valencia, cable bridge, panoramio,com.

They are held up by cables, like suspension bridges.

However, in a cablestayed bridge less wire is required and the towers holding the cables are proportionately higher. The suspension bridge can be viewed as an upside-down arch in tension with only the towers in compression. Because the deck is hung in the air, care must be taken to ensure that it does not move excessively under loading.

BRIDGE TYPES BY USE

A bridge can be categorized by what it is designed to carry, such as 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 rail traffic. Some bridges Novy Most bridge, Bratislava, grayline, com.

accommodate

other

purposes,

such as the tower of Novy Most Bridge in Bratislava, which features a restaurant.

There are also car traffic, train, pedestrian, double-decked, pipeline bridges as well as viaducts.

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AESTHETICS

Copenhagen harbour bridge, orangesmile,com.

Most

bridges

are

utilitarian

in

appearance, but in some cases, the appearance of the bridge can have great importance. Often, this is the case with a large bridge that serves as an entrance to a city, or crosses over a main harbour entrance.

These

are

sometimes

known

as signature bridges.

BENEFITS OF BRIDGES

Bridges provide a passageway for transportation including automobiles, ferries, ships and trains in less time. Apart from that, they link areas within the same country or even areas in different countries. 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!

fatbmx.com

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THE MOST IMPORTANT BRIDGES OF GREECE

By Thanassis Stafylidis The Tatarna Bridge is a road bridge over the Kremasta artificial lake (which is fed and drained by the river Acheloos) in northwestern Greece. Kremasta dam was built in the 1960s.

Near the old Tatarna bridge the first battle of the Greeks from Roumeli against the Turks during the struggle for independence (1821) took place.

Not very far from the new bridge is located an abyss hole on the ground. According to confirmed information by locals, eyewitnesses and others, many opponents to the ELAS (EAM) organization (during the civil war) were thrown alive, or after they were killed, inside the abyss hole.

It was designed by Aristarchos Oikonomou, and built between 1971 and 1973. It is a box girder bridge with three spans; the largest span is 196 m. The bridge is situated on the border of the regional units Acarnania –Etolia and Evrytania. The name Tatarna comes from a nearby monastery.

History Greece,com.

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In the same place there was a 17th-century arch stone bridge over the river Acheloos.

Adjacent to the old bridge was the largest spring of the Acheloos. Both the bridge and the spring were submerged when the Kremasta dam was constructed.

The Arkadiko Bridge or Kazarma Bridge is a Mycenaean bridge near the modern road from Tiryns to Epidaurus on the Peloponnese, Greece. Dating to the Greek Bronze Age, it is one of the oldest arch bridges still in existence and use.

The corbel arch bridge belonged in Mycenaean times to a highway between the two cities, which formed part of a wider military road network. It has a culvert span of ca.

1 m and is made in the typical Mycenaean manner of Cyclopean stones. The structure is 22 metres (72 ft) long, 5.60 metres (18.4 ft) wide at the base and 4 metres (13 ft) high. The width of the roadway atop is about 2.50 metres (8 ft 2 in). The sophisticated layout of the bridge and the road indicate that they were specifically constructed for use by chariots. Built in the Late Helladic III (ca. 1300–1190 BC), the bridge is still used by the local populace.

en.wikipedia,org.

The Bridge of Arta is a stone bridge that crosses the Arachthos river in the west of the city of Arta in Greece. It has been rebuilt many times over the centuries, starting with Roman or perhaps older foundations; the current bridge is probably a 17th-century Ottoman construction.

The folk ballad "The Bridge of Arta" tells a story of human sacrifice during its building. From the ballad, a number Greek

en.wikipedia,org.

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proverbs and colloquial expressions arose, associated with interminable delays, as in the text of the ballad: "All day they were building it, and in the night it would collapse."

History According to the Epirote chronicler Panayiotis Aravantinos, the bridge was first built under the Roman Empire. Some traditions say it was rebuilt when Arta became capital of the Despotate of Epirus, possibly under Michael II Doukas(1230–1271).

The current version is Ottoman, probably from 1602-1606 or perhaps 1613. From 1881-1912, the highest point of the bridge was the border between the Ottoman Empire and the Kingdom of Greece.

The Rio–Antirio bridge, officially the Charolaos Trikoupis Bridge after the statesman who first envisaged it, is one of the world's longest multi-span cable-stayed bridges and the longest of the fully suspended type. It crosses the Gulf of Corinth near Patras, linking the town of Rio on the Peloponnese peninsula to Antirrio on mainland Greece by road.

It has two vehicle lanes per direction, an emergency lane and a pedestrian walkway.

Its five-span four-pylon cable-stayed portion of length 2,252 m (7,388 ft) is the world's second longest cable-stayed deck.

Name Its official name is the Charilaos Trikoupis Bridge. Charilaos Trikoupis was a 19thcentury Greek Prime Minister; he suggested the idea of building a bridge between Rio and Antirrio. The project was too expensive at the time, when Greece was trying to get a late start in the Industrial Revolution.

pxleyes.com

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The Lake Polyphytos Bridge or the Servia / Neraida High Bridge is one of the longest bridges in Greece, with a length of 1,372 m. Construction began in 1972 along with the artificial lake and was completed in 1975.

The bridge is a part of the GR3-E65 (Athens- Lamia- Larissa- Kozani- Florina) and is located 15 km southeast of the city of Kozani and 5 km northwest of Servia. It is one of the two bridges of the lake; the other is the Rymnios Bridge to the southwest near Aiani.

.

en.wikipedia.org

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