Pontoon bridge
Overview
 
A pontoon bridge or floating bridge is a bridge
Bridge
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...

 that floats on water and in which barge- or boat-like pontoon
Pontoon (boat)
A pontoon is a flotation device with buoyancy sufficient to float itself as well as a heavy load. A pontoon boat is a flattish boat that relies on pontoons to float. Pontoons may be used on boats, rafts, barges, docks, floatplanes or seaplanes. Pontoons may support a platform, creating a raft. A...

s support the bridge deck and its dynamic loads. While pontoon bridges are usually temporary structures, some are used for long periods of time. Permanent floating bridges are useful for sheltered water-crossings where it is not considered economically feasible to suspend a bridge from anchored pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...

s.
Encyclopedia
A pontoon bridge or floating bridge is a bridge
Bridge
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...

 that floats on water and in which barge- or boat-like pontoon
Pontoon (boat)
A pontoon is a flotation device with buoyancy sufficient to float itself as well as a heavy load. A pontoon boat is a flattish boat that relies on pontoons to float. Pontoons may be used on boats, rafts, barges, docks, floatplanes or seaplanes. Pontoons may support a platform, creating a raft. A...

s support the bridge deck and its dynamic loads. While pontoon bridges are usually temporary structures, some are used for long periods of time. Permanent floating bridges are useful for sheltered water-crossings where it is not considered economically feasible to suspend a bridge from anchored pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...

s. Such bridges can require a section that is elevated, or can be raised or removed, to allow ship
Ship
Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

s to pass.

Pontoon bridges are especially useful in war
War
War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

time as river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 crossings. Such bridges are usually temporary, and are sometimes destroyed after crossing (to keep the enemy from using them), or collapsed and carried (if on a long march). They were used to great advantage in many battle
Battle
Generally, a battle is a conceptual component in the hierarchy of combat in warfare between two or more armed forces, or combatants. In a battle, each combatant will seek to defeat the others, with defeat determined by the conditions of a military campaign...

s throughout time, including the Battle of Garigliano
Battle of Garigliano (1503)
The Battle of Garigliano was fought on December 29, 1503 between a Spanish army under Gonzalo Fernández de Córdoba and a French army commanded by Ludovico II, Marquis of Saluzzo.-Preliminary phase:...

, the Battle of Oudenarde
Battle of Oudenarde
The Battle of Oudenaarde was a key battle in the War of the Spanish Succession fought on 11 July 1708 between the forces of Great Britain, the Dutch Republic and the Holy Roman Empire on the one side and the French on the other...

, and many others.

Pontoon bridges have been in use since ancient times.

Ancient China

In ancient China, the Zhou Dynasty
Zhou Dynasty
The Zhou Dynasty was a Chinese dynasty that followed the Shang Dynasty and preceded the Qin Dynasty. Although the Zhou Dynasty lasted longer than any other dynasty in Chinese history, the actual political and military control of China by the Ji family lasted only until 771 BC, a period known as...

 Chinese text of the Shi Jing
Shi Jing
The Classic of Poetry , translated variously as the Book of Songs, the Book of Odes, and often known simply as its original name The Odes, is the earliest existing collection of Chinese poems and songs. It comprises 305 poems and songs, with many range from the 10th to the 7th centuries BC...

(Book of Odes) records that King Wen of Zhou
King Wen of Zhou
King Wen of Zhou family name : Ji , Clan name : Zhou Personal name: Chang, known as Zhou Chang or Xibo Chang was the founder of the Zhou Dynasty and the first epic hero of Chinese history....

 was the first to create a pontoon bridge in the 11th century BC. However, the historian Joseph Needham
Joseph Needham
Noel Joseph Terence Montgomery Needham, CH, FRS, FBA , also known as Li Yuese , was a British scientist, historian and sinologist known for his scientific research and writing on the history of Chinese science. He was elected a fellow of the Royal Society in 1941, and as a fellow of the British...

 has pointed out that in all likely scenarios, the temporary pontoon bridge was invented during the 9th or 8th century BC in China, as this part was perhaps a later addition to the book (considering how the book had been edited up until the Han Dynasty
Han Dynasty
The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...

, 202 BC–220 AD). Although earlier temporary pontoon bridges had been made in China, the first secure and permanent ones (and linked with iron chains) in China came first during the Qin Dynasty
Qin Dynasty
The Qin Dynasty was the first imperial dynasty of China, lasting from 221 to 207 BC. The Qin state derived its name from its heartland of Qin, in modern-day Shaanxi. The strength of the Qin state was greatly increased by the legalist reforms of Shang Yang in the 4th century BC, during the Warring...

 (221 BC–207 BC). The later Song Dynasty
Song Dynasty
The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a...

 (960–1279 AD) Chinese statesman Cao Cheng once wrote of early pontoon bridges in China (spelling of Chinese in Wade-Giles
Wade-Giles
Wade–Giles , sometimes abbreviated Wade, is a romanization system for the Mandarin Chinese language. It developed from a system produced by Thomas Wade during the mid-19th century , and was given completed form with Herbert Giles' Chinese–English dictionary of 1892.Wade–Giles was the most...

 format):
During the Eastern Han Dynasty (25–220 AD), the Chinese created a very large pontoon bridge that spanned across the width of the Yellow River
Yellow River
The Yellow River or Huang He, formerly known as the Hwang Ho, is the second-longest river in China and the sixth-longest in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai Province in western China, it flows through nine provinces of China and empties into...

. There was also the rebellion of Gongsun Shu in 33 AD, where a large pontoon bridge with fortified posts was constructed across the Yangtze River, eventually broken through with ramming
Ramming
In warfare, ramming is a technique that was used in air, sea and land combat. The term originated from battering ram, a siege weapon used to bring down fortifications by hitting it with the force of the ram's momentum...

 ships by official Han troops under Commander Cen Peng. During the late Eastern Han into the Three Kingdoms
Three Kingdoms
The Three Kingdoms period was a period in Chinese history, part of an era of disunity called the "Six Dynasties" following immediately the loss of de facto power of the Han Dynasty rulers. In a strict academic sense it refers to the period between the foundation of the state of Wei in 220 and the...

 period, during the Battle of Chibi in 208 AD, the Prime Minister Cao Cao
Cao Cao
Cao Cao was a warlord and the penultimate chancellor of the Eastern Han Dynasty who rose to great power during the dynasty's final years. As one of the central figures of the Three Kingdoms period, he laid the foundations for what was to become the state of Cao Wei and was posthumously titled...

 once linked the majority of his fleet together with iron chains, which proved to be a fatal mistake once he was thwarted with a fire attack by Sun Quan
Sun Quan
Sun Quan , son of Sun Jian, formally Emperor Da of Wu, was the founder of Eastern Wu during the Three Kingdoms period of Chinese history. He ruled from 222 to 229 as King of Wu and from 229 to 252 as Emperor of Wu....

's fleet.
The armies of Emperor Taizu of Song
Emperor Taizu of Song
Emperor Tàizǔ , born Zhao Kuangyin , was the founder of the Song Dynasty of China, reigning from 960 to 976.-Ancestry and early life:...

 had a large pontoon bridge built across the Yangtze River in 974 in order to secure supply lines during the Song Dynasty
Song Dynasty
The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a...

's conquest of the Southern Tang
Southern Tang
Southern Tang was one of the Ten Kingdoms in south-central China created following the Tang Dynasty from 937-975. Southern Tang replaced the Wu Kingdom when Li Bian deposed the emperor Yang Pu....

.

On October 22, 1420, Ghiyasu'd-Din Naqqah, the official diarist of the embassy sent by the Timurid ruler
Timurid Dynasty
The Timurids , self-designated Gurkānī , were a Persianate, Central Asian Sunni Muslim dynasty of Turko-Mongol descent whose empire included the whole of Iran, modern Afghanistan, and modern Uzbekistan, as well as large parts of contemporary Pakistan, North India, Mesopotamia, Anatolia and the...

 of Persia, Mirza Shahrukh
Shah Rukh (Timurid dynasty)
Shāhrukh Mīrzā was the ruler of the eastern portion of the empire established by the Central Asian warlord Timur - the founder of the Timurid dynasty - governing most of Persia and Transoxiana between 1405 and 1447...

 (r. 1404–1447), to the Ming Dynasty
Ming Dynasty
The Ming Dynasty, also Empire of the Great Ming, was the ruling dynasty of China from 1368 to 1644, following the collapse of the Mongol-led Yuan Dynasty. The Ming, "one of the greatest eras of orderly government and social stability in human history", was the last dynasty in China ruled by ethnic...

 of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 during the reign of the Yongle Emperor
Yongle Emperor
The Yongle Emperor , born Zhu Di , was the third emperor of the Ming Dynasty of China from 1402 to 1424. His Chinese era name Yongle means "Perpetual Happiness".He was the Prince of Yan , possessing a heavy military base in Beiping...

 (r. 1402–1424), recorded his sight and travel over a large floating pontoon bridge at Lanzhou
Lanzhou
Lanzhou is the capital and largest city of Gansu Province in Northwest China. A prefecture-level city, it is a key regional transportation hub, allowing areas further west to maintain railroad connections to the eastern half of the country....

 (constructed earlier in 1372) as he crossed the Yellow River
Yellow River
The Yellow River or Huang He, formerly known as the Hwang Ho, is the second-longest river in China and the sixth-longest in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai Province in western China, it flows through nine provinces of China and empties into...

 on this day. He wrote that it was:

Greco-Roman era

The Greek
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

 writer Herodotus
Herodotus
Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...

 in his Histories
Histories (Herodotus)
The Histories of Herodotus is considered one of the seminal works of history in Western literature. Written from the 450s to the 420s BC in the Ionic dialect of classical Greek, The Histories serves as a record of the ancient traditions, politics, geography, and clashes of various cultures that...

, records several pontoon bridges. For Emperor Darius I The Great of Persia (522 BC–485 BC), the Greek Mandrocles of Samos once engineered a pontoon bridge that stretched across the Bosporus
Bosporus
The Bosphorus or Bosporus , also known as the Istanbul Strait , is a strait that forms part of the boundary between Europe and Asia. It is one of the Turkish Straits, along with the Dardanelles...

, linking Asia to Europe, so that Darius could pursue the fleeing Scythians as well as move his army into position in the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...

 to overwhelm Macedon
Macedon
Macedonia or Macedon was an ancient kingdom, centered in the northeastern part of the Greek peninsula, bordered by Epirus to the west, Paeonia to the north, the region of Thrace to the east and Thessaly to the south....

. Another spectacular pontoon bridge was a pair of floating bridges across the Hellespont by Xerxes I in 480 BC to transport his huge army into Europe:
The late Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 writer Vegetius
Vegetius
Publius Flavius Vegetius Renatus, commonly referred to simply as Vegetius, was a writer of the Later Roman Empire. Nothing is known of his life or station beyond what he tells us in his two surviving works: Epitoma rei militaris , and the lesser-known Digesta Artis Mulomedicinae, a guide to...

, in his work De Re Militari
De Re Militari
De Re Militari , also Epitoma Rei Militaris, is a treatise by the late Latin writer Vegetius about Roman warfare and military principles as a presentation of methods and practices in use during the height of Rome's power, and responsible for that power...

, wrote:
The emperor Caligula
Caligula
Caligula , also known as Gaius, was Roman Emperor from 37 AD to 41 AD. Caligula was a member of the house of rulers conventionally known as the Julio-Claudian dynasty. Caligula's father Germanicus, the nephew and adopted son of Emperor Tiberius, was a very successful general and one of Rome's most...

 is said to have ridden a horse across a pontoon bridge stretching two miles between Baiae
Baiae
Baiae , a frazione of the comune of Bacoli) in the Campania region of Italy was a Roman seaside resort on the Bay of Naples. It was said to have been named after Baius, who was supposedly buried there. Baiae was for several hundred years a fashionable resort, especially towards the end of the Roman...

 and Puteoli while wearing the armour of Alexander the Great to mock a soothsayer
Soothsayer
Soothsayer may refer to:* One practicing divination, including:** Fortune-teller** Oracle* The Soothsayer, an album by Wayne Shorter* "Soothsayer", a song by Buckethead from Crime Slunk Scene...

 who had claimed he had "no more chance of becoming emperor than of riding a horse across the Bay of Baiae". Caligula's construction of the bridge cost a massive sum of money and added to discontent with his rule.

Middle Ages

Although pontoons declined in use during the European Middle Ages, they were still used alongside regular boats to span rivers during campaigns, or to link communities which lacked resources to build permanent bridges.

Early modern period

In the 1670s, the French devised the copper pontoon; after this point, rivers and canals ceased to present significant obstacles. The early modern period in pontoon use was dominated by the wars of the 18th and 19th centuries during which the art and science of pontoon bridging barely changed.

Modern use

Pontoons were extensively used by both the armies and civilians throughout the first half of the 20th century and both World Wars, particularly on the Eastern Front by the Red Army which developed fast assault pontoon bridging techniques to facilitate their offensive operations.
The longest military pontoon bridge ever constructed across a river was built in 1995 by the 502nd Engineer Company, as part of IFOR
IFOR
The Implementation Force was a NATO-led multinational peacekeeping force in Bosnia and Herzegovina under a one-year mandate from 20 December 1995 to 20 December 1996 under the codename Operation Joint Endeavour. Its task was to implement the military Annexes of The General Framework Agreement for...

. It was assembled under adverse weather conditions across the Sava near Županja
Županja
Županja is a city in eastern Slavonia, Croatia, located 254 km east of Zagreb. It is administratively part of the Vukovar-Syrmia county. It is inhabited by 12,185 people ....

 (between Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

 and Bosnia
Bosnia and Herzegovina
Bosnia and Herzegovina , sometimes called Bosnia-Herzegovina or simply Bosnia, is a country in Southern Europe, on the Balkan Peninsula. Bordered by Croatia to the north, west and south, Serbia to the east, and Montenegro to the southeast, Bosnia and Herzegovina is almost landlocked, except for the...

), and had a total length of 2034 feet (620 m). It was disassembled in 1996.

Modern variants of the pontoon bridge are still essential and in use by modern armies. As an example, the American Army has developed a version dubbed the "Assault Float Ribbon Bridge". It was constructed during combat by the 299th Multi-role Bridge Company, USAR
United States Army Reserve
The United States Army Reserve is the federal reserve force of the United States Army. Together, the Army Reserve and the Army National Guard constitute the reserve components of the United States Army....

 on the Euphrates River at Objective Peach near Al Musayib on the night of 3 April 2003. This took place during the 2003 invasion of Iraq
2003 invasion of Iraq
The 2003 invasion of Iraq , was the start of the conflict known as the Iraq War, or Operation Iraqi Freedom, in which a combined force of troops from the United States, the United Kingdom, Australia and Poland invaded Iraq and toppled the regime of Saddam Hussein in 21 days of major combat operations...

 by American and British forces. The 185-meter Assault Float Bridge was built to support retrograde operations because of the heavy-armor traffic crossing a partially destroyed highway
Highway
A highway is any public road. In American English, the term is common and almost always designates major roads. In British English, the term designates any road open to the public. Any interconnected set of highways can be variously referred to as a "highway system", a "highway network", or a...

 span. That same night, the 299th also constructed a 40 metres (131.2 ft) single-story Medium Girder Bridge
Medium Girder Bridge
The Medium Girder Bridge is a lightweight, man portable bridge and can be assembled without help from heavy equipment. In addition, it is also a deck type, two-girder bridging system capable of carrying loads up to and including Main battle tanks .MGB was originally produced by Fairey Engineering...

 to patch the damage done to the highway span. The 299th was part of the U.S. Army's 3rd Infantry Division as they crossed the border into Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....

 on 20 March 2003. Examples of the construction and use of pontoon bridges during combat operations date back through World War II and earlier.

Design

When designing a pontoon bridge, the engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...

 must take into consideration the maximum amount of load
Structural load
Structural loads or actions are forces, deformations or accelerations applied to a structure or its components.Loads cause stresses, deformations and displacements in structures. Assessment of their effects is carried out by the methods of structural analysis...

 that it is intended to support. Each pontoon can support a load equal to the mass of the water that it displaces
Displacement (fluid)
In fluid mechanics, displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, as in the illustration, and from this the volume of the immersed object can be deduced .An object that sinks...

, but this load also includes the mass of the bridge itself. If the maximum load of a bridge section is exceeded, one or more pontoons become submerged and will proceed to sink. The roadway across the pontoons must also be able to support the load, yet be light enough not to limit their carrying capacity.

Prior to the advent of modern military pontoon bridge-building equipment, floating bridges were typically constructed using wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

. Such a wooden floating bridge could be built in a series of sections, starting from an anchor
Anchor
An anchor is a device, normally made of metal, that is used to connect a vessel to the bed of a body of water to prevent the vessel from drifting due to wind or current. The word derives from Latin ancora, which itself comes from the Greek ἄγκυρα .Anchors can either be temporary or permanent...

ed point on the shore
Shore
A shore or shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In Physical Oceanography a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore,...

. Pontoons were formed using boat
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...

s; several barrels lashed together; raft
Raft
A raft is any flat structure for support or transportation over water. It is the most basic of boat design, characterized by the absence of a hull...

s of timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...

s, or some combination of these. Each bridge section consisted of one or more pontoons, which were maneuvered into position and then anchored. These pontoons were then linked together using wooden stringer
Stringer
Stringer may refer to:* Stringer , a type of freelance journalism* Stringer * Stringer , or longeron, a strip of wood or metal to which the skin of an aircraft is fastened...

s called balks. The balks were then covered by a series of cross plank
Plank
Plank may refer to:*Plank *Plank , an isometric exercise for the abdominal muscles*The Plank , a British comedy film with no dialogue*The Plank , a remake of the 1967 film...

s called chesses to form a road surface, and the chesses were held in place with side guard rail
Guard rail
Guard rail or guardrail, sometimes referred to as guide rail or railing, is a system designed to keep people or vehicles from straying into dangerous or off-limits areas...

s. The bridge was repeatedly extended in this manner until the opposite bank was reached.

Precautions are needed to protect a pontoon bridge from becoming damaged. The bridge can be dislodged or inundated whenever the load limit of the bridge is exceeded. A pontoon bridge can also become overloaded when one section of the bridge is weighted down much more heavily than the other parts. The bridge can be induced to sway or oscillate in a hazardous manner because of the regular stride
Stride
Stride can stand for:* A period of locomotion defined by the complete cycle of a reference limb. See gait* In music:** STRIDE - An indie rock n roll band from North East Scotland** Stride , a type of piano playing...

 of a group of soldier
Soldier
A soldier is a member of the land component of national armed forces; whereas a soldier hired for service in a foreign army would be termed a mercenary...

s, or from other types of repeated loads. Drift
Drift
- Film and literature :* Drift , a 2002 Doctor Who novel* Drift , a series of Japanese films written and directed by Futoshi Jinno* Drift, 2007 experimental short film by Max Hattler* Drift , a fictional character...

 and heavy floating objects can also accumulate on the pontoons, increasing the drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

 from river current
Current (stream)
A current, in a river or stream, is the flow of water influenced by gravity as the water moves downhill to reduce its potential energy. The current varies spatially as well as temporally within the stream, dependent upon the flow volume of water, stream gradient, and channel geometrics...

 and potentially damaging the bridge.

Submerged floating-tube bridges have been considered for use across ocean strait
Strait
A strait or straits is a narrow, typically navigable channel of water that connects two larger, navigable bodies of water. It most commonly refers to a channel of water that lies between two land masses, but it may also refer to a navigable channel through a body of water that is otherwise not...

s and even across entire ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

s. It is estimated that a submerged floating tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 would be two to three times more costly to build than a floating bridge
Bridge
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...

, and the technology remains unproven. No submerged floating tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 exists in the world at present.

Historic

  • A two-kilometre pontoon bridge was used by Persian Emperor Darius to cross the Bosphorus.
  • The original London Bridge
    London Bridge
    London Bridge is a bridge over the River Thames, connecting the City of London and Southwark, in central London. Situated between Cannon Street Railway Bridge and Tower Bridge, it forms the western end of the Pool of London...

     was a pontoon bridge.
  • A two-mile bridge was built for Emperor Caligula at Baiae
    Baiae
    Baiae , a frazione of the comune of Bacoli) in the Campania region of Italy was a Roman seaside resort on the Bay of Naples. It was said to have been named after Baius, who was supposedly buried there. Baiae was for several hundred years a fashionable resort, especially towards the end of the Roman...

     in 37 AD.
  • Pontoon bridges saw extensive usage during the American Civil War
    American Civil War
    The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

    . An innovative light-weight design known as Cumberland Pontoons
    Cumberland Pontoons
    Cumberland pontoons were a novel design of pontoon bridges developed during the American Civil War to facilitate the movement of Union forces across the rivers of the Mid-South as the Federal forces advanced southward through Tennessee and Georgia....

     were widely used during the Atlanta Campaign
    Atlanta Campaign
    The Atlanta Campaign was a series of battles fought in the Western Theater of the American Civil War throughout northwest Georgia and the area around Atlanta during the summer of 1864. Union Maj. Gen. William T. Sherman invaded Georgia from the vicinity of Chattanooga, Tennessee, beginning in May...

     to transport soldiers and artillery
    Artillery
    Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

     across rivers in the South
    Southern United States
    The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...

    .
  • During the Yugoslav wars
    Yugoslav wars
    The Yugoslav Wars were a series of wars, fought throughout the former Yugoslavia between 1991 and 1995. The wars were complex: characterized by bitter ethnic conflicts among the peoples of the former Yugoslavia, mostly between Serbs on the one side and Croats and Bosniaks on the other; but also...

     of the 1990s, the Maslenica Bridge
    Maslenica Bridge (D8)
    The Maslenica Bridge is a deck arch bridge carrying the D8 state road approximately to the west of the settlement of Maslenica, Croatia and south of the D54 and D8 state roads junction.- Structure :...

     was destroyed and a short pontoon bridge was built by Croatia
    Croatia
    Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

    n civilian and military authorities in July 1993 over a narrow sea outlet in the town of Maslenica
    Maslenica
    Maslenica is a port and village in Zadar County, Dalmatia, Croatia.Its geographical coordinates are 44°13'N, 15°32'E. It is situated in Novigrad Sea, the gulf of Novigrad. Waters are quite clear due to the Zrmanja river which flows into this gulf.- History :...

    , after the territory was retaken
    Operation Maslenica
    In early September, 1991, during the opening stages of the Croatian War of Independence, Serb-dominated units of the Knin Corps of the Yugoslav People's Army , under the command of Colonel Ratko Mladić and supported by the ethnic Serb Krajina militia, conducted offensive operations against areas...

     from Serbian Krajina. Between 1993 and 1995 the pontoon served as one of the two operational land links toward Dalmatia
    Dalmatia
    Dalmatia is a historical region on the eastern coast of the Adriatic Sea. It stretches from the island of Rab in the northwest to the Bay of Kotor in the southeast. The hinterland, the Dalmatian Zagora, ranges from fifty kilometers in width in the north to just a few kilometers in the south....

     and Croat- and Bosnian Muslim-held areas of Bosnia-Herzegovina that did not go through Serb-held territory.

Current


  • Governor Albert D. Rosellini Bridge — Evergreen Point
    Evergreen Point Floating Bridge
    The Governor Albert D. Rosellini Bridge—Evergreen Point is the longest floating bridge on Earth at and carries State Route 520 across Lake Washington from Seattle to Medina.The Evergreen Point of the bridge's original name is the westernmost of the three small Eastside...

    • Completed 1963. Span 7578 feet (2,310 m).
    • Spans Lake Washington
      Lake Washington
      Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

       in Washington State, carrying State Route 520 from Seattle
      Seattle, Washington
      Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

       to Medina
      Medina, Washington
      Medina is a city located in the Eastside, a region of King County, Washington, United States. Surrounded on the north, west, and south by Lake Washington, opposite Seattle, Medina is bordered by Clyde Hill and Hunts Point, as well as the satellite city of Bellevue. The city's population was 2,969...

      . A toll bridge until 1979, its common name is the Evergreen Point Floating Bridge
      Evergreen Point Floating Bridge
      The Governor Albert D. Rosellini Bridge—Evergreen Point is the longest floating bridge on Earth at and carries State Route 520 across Lake Washington from Seattle to Medina.The Evergreen Point of the bridge's original name is the westernmost of the three small Eastside...

      . It is the longest floating bridge in the world.
    • Currently, the Evergreen Point Floating Bridge is one of the Projects that the Washington State Department of Transportation (WSDOT) is conducting. Because of the age of the bridge and its inability to withstand more than a 20-year storm, it is planned to be replaced in the future with another, more modern floating bridge.
  • Lacey V. Murrow Memorial Bridge
    Lacey V. Murrow Memorial Bridge
    The Lacey V. Murrow Memorial Bridge is a floating bridge that carries the eastbound lanes of Interstate 90 across Lake Washington from Seattle to Mercer Island, Washington. It is the second longest floating bridge on Earth at , whereas the longest is the Evergreen Point Floating Bridge just a few...

    • Original bridge completed in 1940 but sank in 1990 because of weather and mishaps in maintenance.
    • Second bridge completed 1993. Span 6620 feet (2,018 m).
    • Spans Lake Washington
      Lake Washington
      Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

       in Washington State, carrying Interstate 90 traffic eastbound from Seattle
      Seattle, Washington
      Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

       to Mercer Island
      Mercer Island, Washington
      Mercer Island is a city in King County, Washington, United States and the name of the island in Lake Washington on which the city sits. The population was 22,699 at the 2010 census....

      . A toll bridge until 1946, its common name is the Lake Washington Floating Bridge
      Lake Washington Floating Bridge
      The Lake Washington Floating Bridge could refer to one of three floating bridges on Lake Washington:* Lacey V. Murrow Memorial Bridge, opened in 1940 to carry U.S. Route 10 and now carries Interstate 90....

      . It was the first floating bridge longer than a mile, and at the time was the longest floating structure in the world. It is the second longest floating bridge in the world.
  • Hood Canal Bridge
    Hood Canal Bridge
    The Hood Canal Bridge is a floating bridge located in the U.S. state of Washington that carries Washington State Route 104 across Hood Canal and connects the Olympic and Kitsap Peninsulas. At long, The Hood Canal Bridge (officially William A. Bugge Bridge) is a floating bridge located in the U.S....

    • Completed 1961. Span 6521 feet (1,988 m).
    • Carries State Route 104 across Hood Canal
      Hood Canal
      Hood Canal is a fjord forming the western lobe, and one of the four main basins, of Puget Sound in the state of Washington. Hood Canal is not a canal in the sense of being a man-made waterway—it is a natural waterway.-Geography:...

       in Washington state. It is the third longest floating bridge in the world.
    • This bridge broke apart in the February 13, 1979 windstorm
      February 13, 1979 Windstorm
      The February 13, 1979 windstorm is a natural phenomenon that took place on February 13, 1979 in Pacific Canada and the United States. During the early morning of February 13, 1979, an intense wave cyclone moved across southern Vancouver Island, British Columbia. South of the low center, a strong...

      . It was rebuilt 3 years later.
  • Demerara Harbour Bridge
    Demerara Harbour Bridge
    The Demerara Harbour Bridge is a long floating toll bridge. It was commissioned on 2 July 1978. The bridge crosses the Demerara River south of the Guyanese capital Georgetown, from Peter's Hall, East Bank Demerara to Schoon Ord, West Bank Demerara. There is a pedestrian footwalk. A raised...

    • Completed 1978. Span 6074 feet (1,851 m).
    • Located immediately south of Georgetown, Guyana
      Georgetown, Guyana
      Georgetown, estimated population 239,227 , is the capital and largest city of Guyana, located in the Demerara-Mahaica region. It is situated on the Atlantic Ocean coast at the mouth of the Demerara River and it was nicknamed 'Garden City of the Caribbean.' Georgetown is located at . The city serves...

      , it is constructed with steel
      Steel
      Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

       pontoon units and is the fourth longest floating bridge in the world.
  • Homer M. Hadley Memorial Bridge
    Homer M. Hadley Memorial Bridge
    The Third Lake Washington Bridge, officially the Homer M. Hadley Memorial Bridge, is the fifth-longest floating bridge in the world, at 5,811 feet...

    • Completed 1989. Span 5811 feet (1,771 m).
    • Spans Lake Washington
      Lake Washington
      Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

       in Washington state, carrying Interstate 90 traffic westbound from Mercer Island
      Mercer Island, Washington
      Mercer Island is a city in King County, Washington, United States and the name of the island in Lake Washington on which the city sits. The population was 22,699 at the 2010 census....

       to Seattle
      Seattle, Washington
      Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

      . It runs parallel to the Lacey V. Murrow Memorial Bridge
      Lacey V. Murrow Memorial Bridge
      The Lacey V. Murrow Memorial Bridge is a floating bridge that carries the eastbound lanes of Interstate 90 across Lake Washington from Seattle to Mercer Island, Washington. It is the second longest floating bridge on Earth at , whereas the longest is the Evergreen Point Floating Bridge just a few...

      , which carries eastbound Interstate 90 Traffic, and is also commonly referred to as the Lake Washington Floating Bridge. It is the fifth longest floating bridge in the world.
  • Nordhordland Bridge
    Nordhordland Bridge
    The Nordhordland Bridge is a combined cable-stayed and pontoon bridge which crosses Salhusfjorden between Klauvaneset and Flatøy in Hordaland, Norway. It is long, of which the pontoon section is long. The cable-stayed section consists of a single tall H-pylon which has a length of and a main...

    • Completed 1994. Span 4086 feet (1,245 m) (the floating bridge part).
    • Located near Bergen, Norway
      Norway
      Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

      , the Nordhordland Bridge consists of a free-floating bridge and a high level cable-stayed bridge
      Cable-stayed bridge
      A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....

      . The free-floating bridge has the longest laterally-unsupported span in the world. It is sometimes referred to as the Salhus Bridge.
    • Architect's web site
  • Bergøysund Floating Bridge
    Bergsøysund Bridge
    Bergsøysund Bridge is a pontoon bridge that crosses the Bergsøysundet strait between the islands of Aspøya and Bergsøya in Møre og Romsdal county, Norway. The bridge is long, the longest span is , and the maximum clearance to the sea is . The bridge has 13 spans.Bergsøysund Bridge was opened in...

    • Completed 1992. Span 3061 feet (933 m).
    • Located in Kristiansund
      Kristiansund
      Kristiansund is a city and municipality on the western coast of Norway, in the Nordmøre district of Møre og Romsdal county. It was officially awarded township status in 1742, and it is still the major town for the region. The administrative center of the municipality is the city of Kristiansund...

      , Norway
      Norway
      Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

      .
  • Galata Bridge
    Galata Bridge
    The Galata Bridge is a bridge that spans the Golden Horn in Istanbul, Turkey. From the end of the 19th century in particular, the bridge has featured in Turkish literature, theater, poetry and novels.-History:...

    • Completed 1875. Span 2985 feet (910 m).
    • Decommissioned 1992.
    • This floating bridge crossed the Golden Horn
      Golden Horn
      The Golden Horn is a historic inlet of the Bosphorus dividing the city of Istanbul and forming the natural harbor that has sheltered Greek, Roman, Byzantine, Ottoman and other ships for thousands of...

       in Turkey
      Turkey
      Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

      . After it was damaged by a 1992 fire, it was towed up the Golden Horn to make way for the fifth and current Galata Bridge, a bascule bridge
      Bascule bridge
      A bascule bridge is a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic....

      .
  • Howrah Bridge
    Howrah Bridge
    The Howrah Bridge is a cantilever bridge that spans the Hooghly River in West Bengal, India. Commissioned in 1943, the bridge was originally named the New Howrah Bridge, because it links the city of Howrah to its twin city, Kolkata . On 14 June 1965 it was renamed Rabindra Setu, after Rabindranath...

    • Completed 1874.
    • Decommissioned 1943
    • This bridge, connected Howrah and Calcutta on opposite banks of Hooghly River, was built using timber on pontoon and was opened to let river traffic through.
  • Okanagan Lake Bridge
    Okanagan Lake Bridge
    The Okanagan Lake Bridge was a three-lane, 2,100 foot/650 metre-long floating bridge in British Columbia, Canada. It crossed Okanagan Lake, connecting the Westside area to Kelowna on the lake's eastern side. Taller boats such as sailboats were able to pass under the lift span which was located at...

    • Completed 1958. Span 2100 feet (640 m).
    • Spans Okanagan Lake
      Okanagan Lake
      Okanagan Lake is a large, deep lake in the Okanagan Valley of British Columbia. The lake is 135 km long, between 4 and 5 km wide, and has a surface area of 351 km². The lake's maximum depth is 232 meters near Grant Island...

       in British Columbia
      British Columbia
      British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

      , carrying Highway 97 to Kelowna
      Kelowna
      Kelowna is a city on Okanagan Lake in the Okanagan Valley, in the southern interior of British Columbia, Canada. Its name derives from a Okanagan language term for "grizzly bear"...

      . This was the first floating bridge built in Canada
      Canada
      Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

      . The old 3 lane floating bridge has been replaced by a new, 5 lane floating bridge. The new bridge — William R. Bennett Bridge
      William R. Bennett Bridge
      The William R. Bennett Bridge is a bridge in the Okanagan Valley of British Columbia, Canada. Completed on May 25, 2008, the bridge replaced the older Okanagan Lake Bridge built in 1958 to link Downtown Kelowna to West Kelowna across Okanagan Lake as part of Highway 97.On April 21, 2005, premier...

       — was completed on May 25, 2008.
  • Dongjin Bridge
    Dongjin Bridge
    The Dongjin Bridge in Ganzhou, Jiangxi province, China is a pontoon bridge constructed over the Zhang River and Gong River in the Chinese Song Dynasty...

     in Ganzhou
    Ganzhou
    Ganzhou is a prefecture-level city in southern Jiangxi province, People's Republic of China. Its administrative seat is at Zhanggong .-History:...

    , China
    China
    Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

    • Pontoon bridges have been constructed over the Zhang and Gong rivers since the Song Dynasty
      Song Dynasty
      The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a...

       (960
      960
      Year 960 was a leap year starting on Sunday of the Julian calendar.- Europe :* Edgar the Peaceable is crowned King of England. Dunstan becomes Archbishop of Canterbury and Edgar's chief adviser. He reforms monasteries and enforces the rule of Saint Benedict: Poverty, Chastity and Obedience for...

      -1279).
    • One of the bridges, the Dongjin Bridge
      Dongjin Bridge
      The Dongjin Bridge in Ganzhou, Jiangxi province, China is a pontoon bridge constructed over the Zhang River and Gong River in the Chinese Song Dynasty...

      , can still be seen.
    • It is 400 metres long, made up of wooden planks placed on around 100 wooden boats linked together with iron chains.
  • Eastbank Esplanade
    Eastbank Esplanade
    The Eastbank Esplanade is a pedestrian and bicycle path along the east shore of the Willamette River in Portland, Oregon, United States...

    • Completed 2001. Span 1200 feet (366 m).
    • Located in Portland, Oregon
      Portland, Oregon
      Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

      , it is the longest floating pedestrian bridge in the United States.
  • Hobart Bridge
    Hobart Bridge
    The Hobart Bridge was a pontoon bridge that crossed the River Derwent, connecting the eastern and western Shores of the City of Hobart, Tasmania, Australia.- History :...

    • Completed 1943. Span 3154 feet (961 m)
    • Spanned the Derwent River at Hobart
      Hobart
      Hobart is the state capital and most populous city of the Australian island state of Tasmania. Founded in 1804 as a penal colony,Hobart is Australia's second oldest capital city after Sydney. In 2009, the city had a greater area population of approximately 212,019. A resident of Hobart is known as...

      , Tasmania
      Tasmania
      Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

    • Constructed of hollow concrete pontoons, it was replaced by a new bridge in 1964
  • Queen Emma Bridge
    Queen Emma Bridge
    The Queen Emma Bridge is a pontoon bridge across St. Anna Bay in Curaçao. It connects the Punda and Otrobanda quarters of the capital city, Willemstad. The bridge is hinged and opens regularly to enable the passage of ocean going vessels. On the opposite end from the hinge is a small shelter where...

    • A pontoon bridge from Punda to Otrabanda across the harbor of Willemstad
      Willemstad, Netherlands Antilles
      Willemstad is the capital city of Curaçao, an island in the southern Caribbean Sea that forms a constituent country of the Kingdom of the Netherlands. Formerly the capital of the Netherlands Antilles prior to its dissolution in 2010, it has an estimated population of 140,000. The historic centre of...

       on the island of Curaçao
      Curaçao
      Curaçao is an island in the southern Caribbean Sea, off the Venezuelan coast. The Country of Curaçao , which includes the main island plus the small, uninhabited island of Klein Curaçao , is a constituent country of the Kingdom of the Netherlands...

      . Notable because this permanent bridge is hinged and opens regularly to enable the passage of ocean going vessels.
    • Span 548 feet (167 m)
  • Sunset Lake Floating Bridge
    Sunset Lake Floating Bridge
    The Sunset Lake Floating Bridge is a floating bridge that spans Sunset Lake in Brookfield, Vermont, United States. The bridge is supported by floating barrels because the lake is too deep for traditional pilings...

    • Located in Brookfield, Vermont
      Brookfield, Vermont
      Brookfield is a town in Orange County, Vermont, United States. It was created by Vermont charter on August 5, 1781. The population was 1,222 at the 2000 census. Brookfield is best known for its floating bridge which spans Sunset Lake buoyed by pontoons...

    • Built on logs in 1820, then upon tarred barrels in 1884, rebuilt using plastic barrels filled with styrofoam in 1978, caries light automobile traffic.
  • Sozh Floating Bridge
    Sozh Floating Bridge
    The Sozh Floating Bridge is a pontoon bridge spanning the Sozh River at Korma, Belarus. It was built in 2003-2004, and caries light automobile traffic....

    • The new floating bridge replaced an older one and spanned the Sozh
      Sozh
      Sozh is an international river flowing in Belarus, Russia and Ukraine. It is a left bank tributary of the Dnieper River. Sozh passes through Gomel, the second largest city in Belarus....

       River at Korma, Belarus
      Belarus
      Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...

    • Built in 2003/2004, caries light automobile traffic.
  • Floating Bridge, Dubai
    Floating Bridge, Dubai
    Floating Bridge is a pontoon bridge in Dubai, United Arab Emirates. It connects Riyadh Road, Dubai Courts and Creek Park on the Bur Dubai side with Baniyas Road, Deira City Centre and the Dubai Creek Golf & Yacht Club on the Deira side. Floating Bridge is the fifth crossing on Dubai Creek...

    , United Arab Emirates
    United Arab Emirates
    The United Arab Emirates, abbreviated as the UAE, or shortened to "the Emirates", is a state situated in the southeast of the Arabian Peninsula in Western Asia on the Persian Gulf, bordering Oman, and Saudi Arabia, and sharing sea borders with Iraq, Kuwait, Bahrain, Qatar, and Iran.The UAE is a...

    • A new floating bridge has been erected over Dubai Creek
      Dubai Creek
      Dubai Creek or Khor Dubai is a saltwater creek located in Dubai, United Arab Emirates . It ends at Ras Al Khor Wildlife Sanctuary. Some sources say that the creek extended as far inland as Al Ain, and that the Ancient Greeks called it River Zara. Historically, the creek divided the city into two...

       to ease traffic on over creek crossings in Dubai (United Arab Emirates)
    • The bridge opened to the public on 16 July 2007; two weeks after applying the Salik
      Salik (road toll)
      Salik is the name given to the electronic toll road system in Dubai, United Arab Emirates. The system has been by some residents of the city state for being an added expense for them. However, in general the system has been well received as a further way of attempting to reduce the serious...

       road toll to the Al Garhoud Bridge
      Al Garhoud bridge
      Al Garhoud Bridge is one of four road bridges over Dubai Creek, and one of five crossing, in Dubai, United Arab Emirates. Al Garhoud Bridge forms the eastern end of the road toll that went into effect on 1 July 2007...

      .

Disasters

Floating bridges can be vulnerable to inclement weather, especially strong winds.
  • In 1979, the longest floating bridge crossing salt water, the Hood Canal Bridge
    Hood Canal Bridge
    The Hood Canal Bridge is a floating bridge located in the U.S. state of Washington that carries Washington State Route 104 across Hood Canal and connects the Olympic and Kitsap Peninsulas. At long, The Hood Canal Bridge (officially William A. Bugge Bridge) is a floating bridge located in the U.S....

    , was subjected to winds of 80 miles per hour (35.8 m/s), gusting up to 120. Waves of 10–15 ft (3–4.6 ) battered the sides of the bridge, and within a few hours the western 3/4 mi of the structure had sunk. It has since been rebuilt.
  • In 1990, the 1940 Lacey V. Murrow Memorial Bridge
    Lacey V. Murrow Memorial Bridge
    The Lacey V. Murrow Memorial Bridge is a floating bridge that carries the eastbound lanes of Interstate 90 across Lake Washington from Seattle to Mercer Island, Washington. It is the second longest floating bridge on Earth at , whereas the longest is the Evergreen Point Floating Bridge just a few...

     was closed for renovations. Specifically, the sidewalks were being removed to widen the traffic lanes to the standards mandated by the Interstate Highway System. Engineers realized that jackhammers could not be employed to remove the sidewalks without risking compromising the structural integrity of the entire bridge. As such, a unique process called hydrodemolition was employed, in which powerful jets of water are used to blast away concrete, bit by bit. The water used in this process was temporarily stored in the hollow chambers in the pontoons of the bridge (to prevent it from contaminating the lake). During a week of rain and strong winds, the watertight doors were not closed and the pontoons filled with water from the storm, in addition to the water from the hydrodemolition. The inundated bridge broke apart and sank. The bridge was rebuilt in 1993.
  • A minor disaster occurs if anchors or connections between the pontoon bridge segments fail. This may happen because of overloading, extreme weather or flood. The bridge disintegrates and parts of it start to float away. Many cases are known. When the Lacey V. Murrow Memorial Bridge sank, it severed the anchor cables of the bridge parallel to it. A powerful tugboat pulled on that bridge against the wind during a subsequent storm, and prevented further damage.

See also

  • Bailey bridge
    Bailey bridge
    The Bailey bridge is a type of portable, pre-fabricated, truss bridge. It was developed by the British during World War II for military use and saw extensive use by both British and the American military engineering units....

     for another bridge type with mobile military application.
  • Bridge of boats
    Bridge of boats
    A "bridge of boats" istype of bridge which floats on water instead of having permanent pillars. It is built by linking boats and the first and last being anchored to the shores. It was used as a military technique since ancient times, being the fastest method for an army to construct a water crossing...

     - a temporary floating bridge built upon general-purpose watercraft
  • Floating dock
    Floating dock
    A floating dock is a platform or ramp supported by pontoons. It is usually joined to the shore with a ramp that rests upon the dock on rollers, to adjust for the vertical movement of the dock...

  • Mabey Logistic Support Bridge
    Mabey Logistic Support Bridge
    The Mabey Logistic Support Bridge is a portable pre-fabricated truss bridge, designed for use by military engineering units to upgrade routes for heavier traffic, replace civilian bridges damaged by enemy action or floods etc, replace assault and general support bridges and to provide a long span...

     bailey type bridge that can be made into a multi-span bridge on pontoons
  • Medium Girder Bridge
    Medium Girder Bridge
    The Medium Girder Bridge is a lightweight, man portable bridge and can be assembled without help from heavy equipment. In addition, it is also a deck type, two-girder bridging system capable of carrying loads up to and including Main battle tanks .MGB was originally produced by Fairey Engineering...

     for another bridge type with mobile military application.
  • Mulberry Harbour
    Mulberry harbour
    A Mulberry harbour was a British type of temporary harbour developed in World War II to offload cargo on the beaches during the Allied invasion of Normandy....

     - as used at D-Day
    D-Day
    D-Day is a term often used in military parlance to denote the day on which a combat attack or operation is to be initiated. "D-Day" often represents a variable, designating the day upon which some significant event will occur or has occurred; see Military designation of days and hours for similar...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK