Suspension bridge
Overview
 
A suspension bridge is a type of 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...

 in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century. Bridges without vertical suspenders
Simple suspension bridge
A simple suspension bridge is an early type of bridge that is supported entirely from anchors at either end, and has no towers or piers. However, it may have saddles...

 have a long history in many mountainous parts of the world.

This type of bridge has cables suspended between tower
Tower
A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....

s, plus vertical suspender cables that carry the weight of the deck below, upon which traffic crosses.
Encyclopedia
A suspension bridge is a type of 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...

 in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century. Bridges without vertical suspenders
Simple suspension bridge
A simple suspension bridge is an early type of bridge that is supported entirely from anchors at either end, and has no towers or piers. However, it may have saddles...

 have a long history in many mountainous parts of the world.

This type of bridge has cables suspended between tower
Tower
A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....

s, plus vertical suspender cables that carry the weight of the deck below, upon which traffic crosses. This arrangement allows the deck to be level or to arc upward for additional clearance. Like other suspension bridge types
Suspension bridge types
A suspension bridge is any type of bridge that makes significant use of tension rather than or in addition to compression. A suspension bridge usually has main cables , anchored at each end of the bridge. Any load applied to the bridge is transformed into a tension in these main cables...

, this type often is constructed without falsework
Falsework
Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself...

.

The suspension cables must be anchored at each end of the bridge, since any load applied to the bridge is transformed into a tension in these main cables. The main cables continue beyond the pillars to deck-level supports, and further continue to connections with anchors in the ground. The roadway is supported by vertical suspender cables or rods, called hangers. In some circumstances the towers may sit on a bluff or canyon edge where the road may proceed directly to the main span, otherwise the bridge will usually have two smaller spans, running between either pair of pillars and the highway, which may be supported by suspender cables or may use a truss bridge to make this connection. In the latter case there will be very little arc in the outboard main cables.

History

The earliest suspension bridges were ropes slung across a chasm, with a deck possibly at the same level or hung below the ropes so that the rope has a catenary
Catenary
In physics and geometry, the catenary is the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight. The curve is the graph of the hyperbolic cosine function, and has a U-like shape, superficially similar in appearance to a parabola...

 shape.

Early precursor

The Tibetan
Tibetan people
The Tibetan people are an ethnic group that is native to Tibet, which is mostly in the People's Republic of China. They number 5.4 million and are the 10th largest ethnic group in the country. Significant Tibetan minorities also live in India, Nepal, and Bhutan...

 saint and bridge-builder Thangtong Gyalpo originated the use of iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

 chains in his version of primitive suspension bridges. In 1433, Gyalpo built eight bridges in eastern Bhutan
Bhutan
Bhutan , officially the Kingdom of Bhutan, is a landlocked state in South Asia, located at the eastern end of the Himalayas and bordered to the south, east and west by the Republic of India and to the north by the People's Republic of China...

. The only surviving chain-linked bridge of Gyalpo's was the Thangtong Gyalpo Bridge in Duksum
Duksum
Duksum is a village in north-eastern Bhutan. It is located in Trashigang District.Population 283 ....

 enroute to Trashi Yangtse, which was finally washed away in 2004. Gyalpo's iron chain bridges did not include a suspended deck bridge
Suspended deck bridge
A suspended bridge deck is a structural element of several different types of bridges. Many designs use a number of vertical cables or bars in tension to support the deck, these elements being attached to an overhead structure of some type:...

 which is the standard on all modern suspension bridges today. Instead, both the railing and the walking layer of Gyalpo's bridges used wires. The stress points that carried the screed were reinforced by the iron chains. Before the use of iron chains it is thought that Gyalpo used ropes from twisted willows or yak skins.

First suspension bridges

The first design for a bridge resembling the modern suspension bridge is attributed to Fausto Veranzio, whose 1595 book “Machinae Novae” included drawings both for a timber and rope suspension bridge, and a hybrid suspension and 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....

 using iron chains (see gallery below).

However, the first suspension bridge actually built was by American engineer and inventor James Finley
James Finley (engineer)
James Finley , aka Judge James Finley, is widely recognized as the first designer and builder of the modern suspension bridge.Born in Maryland, Finley moved to a farm in Fayette County, Pennsylvania, near Uniontown...

 at Jacob’s Creek, in Westmoreland County, Pennsylvania
Westmoreland County, Pennsylvania
-Demographics:As of the census of 2000, there were 369,993 people, 149,813 households, and 104,569 families residing in the county. The population density was 361 people per square mile . There were 161,058 housing units at an average density of 157 per square mile...

, in 1801. Finley's bridge was the first to incorporate all of the necessary components of a suspension bridge, including a suspended deck bridge which hung by trusses. In 1808, Finley had patented the suspension bridge and by 1810, he published his design in a New York journal entitled The Port Folio.

Early British chain bridges included the Dryburgh Abbey Bridge (1817) and 137 m Union Bridge
Union Bridge (Tweed)
The Union Bridge is a suspended-deck suspension bridge that spans the River Tweed between Horncliffe, Northumberland, England and Fishwick, Borders, Scotland...

 (1820), with spans rapidly increasing to 176 m with the Menai Suspension Bridge
Menai Suspension Bridge
The Menai Suspension Bridge is a suspension bridge between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it was the first modern suspension bridge in the world.-Construction:...

 (1826). The Clifton Suspension Bridge
Clifton Suspension Bridge
Brunel died in 1859, without seeing the completion of the bridge. Brunel's colleagues in the Institution of Civil Engineers felt that completion of the Bridge would be a fitting memorial, and started to raise new funds...

 shown above (designed in 1831, completed in 1864 with a 214 m central span) is one of the longest of the parabolic arc chain type.

Wire-cable

The first wire-cable suspension bridge was the Footbridge at Falls of Schuylkill
Footbridge at Falls of Schuylkill
Spider Bridge at Falls of Schuylkill was an iron-wire footbridge erected in 1816 over the Schuylkill River, north of Philadelphia, Pennsylvania. Though a modest and temporary structure, it is thought to have been the first wire-cable suspension bridge in history.-Chain bridge:Prior to the Spider...

 (1816), a modest and temporary structure built following the collapse of James Finley's Chain Bridge at Falls of Schuylkill
Chain Bridge at Falls of Schuylkill
Chain Bridge at Falls of Schuylkill was an 1808 chain suspension bridge built across the Schuylkill River, north of Philadelphia, Pennsylvania. Designed by James Finley, it became the model for his later chain suspension bridges....

 (1808), shown above. The footbridge's span was 124 m, although its deck was only 0.45 m wide.
Development of wire-cable suspension bridges dates to the temporary simple suspension bridge at Annonay
Annonay
Annonay is a commune in the north of the Ardèche department in the Rhône-Alpes region in southern France. It is the most populous commune in the Ardèche department, although it is not the capital, which resides in the smaller town of Privas.-Geography:...

 built by Marc Seguin
Marc Seguin
Marc Seguin was a French engineer, inventor of the wire-cable suspension bridge and the multi-tubular steam-engine boiler.- Biography :...

 and his brothers in 1822. It spanned only 18 m. The first permanent wire cable suspension bridge was Guillaume Henri Dufour
Guillaume Henri Dufour
Guillaume-Henri Dufour was a Swiss army officer, bridge engineer and topographer. He served under Napoleon I and held the office of General to lead the Swiss forces to victory against the Sonderbund. He presided over the First Geneva Convention which established the International Red Cross...

’s Saint Antoine Bridge in Geneva
Geneva
Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

 of 1823, with two 40 m spans. The first with cables assembled in mid-air in the modern method was Joseph Chaley
Joseph Chaley
Joseph Chaley was a French civil engineer and a pioneer designer of suspension bridges in the 19th century. He was a medical officer in the army before becoming a bridge designer....

’s Grand Pont Suspendu in Fribourg
Fribourg
Fribourg is the capital of the Swiss canton of Fribourg and the district of Sarine. It is located on both sides of the river Saane/Sarine, on the Swiss plateau, and is an important economic, administrative and educational center on the cultural border between German and French Switzerland...

, in 1834.

In the United States, the first major wire-cable suspension bridge was the Wire Bridge at Fairmount in Philadelphia, Pennsylvania. Designed by Charles Ellet, Jr.
Charles Ellet, Jr.
Charles Ellet, Jr. was a civil engineer and a colonel during the American Civil War, mortally wounded at the Battle of Memphis.-Biography:Ellet was born in Bucks County, Pennsylvania, brother of Alfred W...

 and completed in 1842, it had a span of 109 m. Ellet's Niagara Falls Suspension Bridge
Niagara Falls Suspension Bridge
The Niagara Falls Suspension Bridge was the world's first working railway suspension bridge. It spanned and stood downstream of Niagara Falls from 1855 to 1897...

 (1847–48) was abandoned before completion, and used as scaffolding
Scaffolding
Scaffolding is a temporary structure used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes or tubes, although it can be from other materials...

 for John A. Roebling
John A. Roebling
John Augustus Roebling was a German-born American civil engineer. He is famous for his wire rope suspension bridge designs, in particular, the design of the Brooklyn Bridge.-Early life:...

's double decker railroad and carriage bridge (1855).

The Otto Beit Bridge (1938–39) was the first modern suspension bridge outside the United States built with parallel wire cables.

Structural analysis


The main forces in a suspension bridge of any type are tension
Tension (mechanics)
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...

 in the cables and compression in the pillars. Since almost all the force on the pillars is vertically downwards and they are also stabilized by the main cables, the pillars
Column
A column or pillar in architecture and structural engineering is a vertical structural element that transmits, through compression, the weight of the structure above to other structural elements below. For the purpose of wind or earthquake engineering, columns may be designed to resist lateral forces...

 can be made quite slender, as on the Severn Bridge
Severn Bridge
The Severn Bridge is a suspension bridge spanning the River Severn between South Gloucestershire, just north of Bristol, England, and Monmouthshire in South Wales, via Beachley, a peninsula between the River Severn and River Wye estuary. It is the original Severn road crossing between England and...

, on the Wales-England border.


In a suspended deck bridge, cables suspended via towers hold up the road deck. The weight is transferred by the cables to the towers, which in turn transfer the weight to the ground.

Assuming a negligible weight as compared to the weight of the deck and vehicles being supported, the main cables of a suspension bridge will form a parabola
Parabola
In mathematics, the parabola is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface...

 (very similar to a catenary
Catenary
In physics and geometry, the catenary is the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight. The curve is the graph of the hyperbolic cosine function, and has a U-like shape, superficially similar in appearance to a parabola...

, the form the unloaded cables take before the deck is added). One can see the shape from the constant increase of the gradient of the cable with linear (deck) distance, this increase in gradient at each connection with the deck providing a net upward support force. Combined with the relatively simple constraints placed upon the actual deck, this makes the suspension bridge much simpler to design and analyze than a 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....

, where the deck is in compression.

Advantages over other bridge types

  • Longer main spans are achievable than with any other type of bridge
  • Less material may be required than other bridge types, even at spans they can achieve, leading to a reduced construction cost
  • Except for installation of the initial temporary cables, little or no access from below is required during construction, for example allowing a waterway to remain open while the bridge is built above
  • May be better to withstand earthquake
    Earthquake
    An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

     movements than heavier and more rigid bridges

Disadvantages compared with other bridge types

  • Considerable stiffness or aerodynamic profiling may be required to prevent the bridge deck vibrating under high winds
  • The relatively low deck stiffness compared to other (non-suspension) types of bridges makes it more difficult to carry heavy rail traffic where high concentrated live loads occur
  • Some access below may be required during construction, to lift the initial cables or to lift deck units. This access can often be avoided in 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....

     construction

Underspanned suspension bridge

In an underspanned suspension bridge, the main cables hang entirely below the bridge deck, but are still anchored into the ground in a similar way to the conventional type. Very few bridges of this nature have been built, as the deck is inherently less stable than when suspended below the cables. Examples include the Pont des Bergues of 1834 designed by Guillaume Henri Dufour
Guillaume Henri Dufour
Guillaume-Henri Dufour was a Swiss army officer, bridge engineer and topographer. He served under Napoleon I and held the office of General to lead the Swiss forces to victory against the Sonderbund. He presided over the First Geneva Convention which established the International Red Cross...

; James Smith’s Micklewood Bridge; and a proposal by Robert Stevenson
Robert Stevenson (civil engineer)
Robert Stevenson FRSE MInstCE FSAS MWS FGS FRAS FSA was a Scottish civil engineer and famed designer and builder of lighthouses.One of his finest achievements was the construction of the Bell Rock Lighthouse.-Early life:...

 for a bridge over the River Almond near Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

.

Roebling's Delaware Aqueduct
Roebling's Delaware Aqueduct
-External links:...

 (begun 1847) consists of three sections supported by cables.
The timber structure essentially hides the cables; and from a quick view, it is not immediately apparent that it is even a suspension bridge.

Suspension cable types

The main suspension cable in older bridges was often made from chain or linked bars, but modern bridge cables are made from multiple strands of wire. This contributes greater redundancy; a few flawed strands in the hundreds used pose very little threat, whereas a single bad link or eyebar
Eyebar
In structural engineering and construction, an eyebar is a straight bar, usually of metal, with a hole at each end for fixing to other components...

 can cause failure of the entire bridge. (The failure of a single eyebar was found to be the cause of the collapse of the Silver Bridge
Silver Bridge
The Silver Bridge collapsed in 1967, killing 46 people. The terms Silver Bridge or Silverbridge may also refer to:* Silver Memorial Bridge, the replacement for the above bridge, opened in 1969....

 over the Ohio River
Ohio River
The Ohio River is the largest tributary, by volume, of the Mississippi River. At the confluence, the Ohio is even bigger than the Mississippi and, thus, is hydrologically the main stream of the whole river system, including the Allegheny River further upstream...

). Another reason is that as spans increased, engineers were unable to lift larger chains into position, whereas wire strand cables can be largely prepared in mid-air from a temporary walkway.

Deck structure types

Most suspension bridges have open truss structures to support the roadbed, particularly owing to the unfavorable effects of using plate girders, discovered from the Tacoma Narrows Bridge (1940)
Tacoma Narrows Bridge (1940)
The 1940 Tacoma Narrows Bridge was the first incarnation of the Tacoma Narrows Bridge, a suspension bridge in the U.S. state of Washington that spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed...

 bridge collapse. Recent developments in bridge aerodynamics have allowed the re-introduction of plate structures. In the picture of the Yichang Bridge
Yichang Bridge
The Yichang Bridge, or Yichang Yangtze Highway Bridge is a suspension bridge that crosses the Yangtze River some 20 km downstream from the center city of Yichang, China. It is located within the prefecture-level city of Yichang, and carries the G50 Shanghai–Chongqing Expressway...

, note the very sharp entry edge and sloping undergirders in the suspension bridge shown. This enables this type of construction to be used without the danger of vortex shedding and consequent aeroelastic effects, such as those that destroyed the original Tacoma Narrows bridge.

Forces acting on suspension bridges

Three kinds of forces operate on any bridge: the dead load, the live load, and the dynamic load. Dead load refers to the weight of the bridge itself. Like any other structure, a bridge has a tendency to collapse simply because of the gravitational forces acting on the materials of which the bridge is made. Live load refers to traffic that moves across the bridge as well as normal environmental factors such as changes in temperature, precipitation, and winds. Dynamic load refers to environmental factors that go beyond normal weather conditions, factors such as sudden gusts of wind and earthquakes. All three factors must be taken into consideration when building a bridge.

Use other than road and rail

The principles of suspension used on the large scale may also appear in contexts less dramatic than road or rail bridges. Light cable suspension may prove less expensive and seem more elegant for a footbridge than strong girder supports. Where such a bridge spans a gap between two buildings, there is no need to construct special towers, as the buildings can anchor the cables. Cable suspension may also be augmented by the inherent stiffness of a structure that has much in common with a tubular bridge
Tubular bridge
A tubular bridge is a bridge built as a rigid box girder section within which the traffic is carried. Famous examples include the original Britannia Bridge over the Menai Strait and the Conwy railway bridge over the River Conwy, designed and tested by William Fairbairn and built by Robert...

.

Construction sequence (wire strand cable type)

Typical suspension bridges are constructed using a sequence generally described as follows. Depending on length and size, construction may take anywhere between a year and a half (construction on the original Tacoma Narrows Bridge took only 19 months) to as many as a decade (the Akashi-Kaikyō Bridge's construction began in May 1986 and was opened in May, 1998 - a total of twelve years).
  1. Where the towers are founded on underwater piers, caissons
    Caisson (engineering)
    In geotechnical engineering, a caisson is a retaining, watertight structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. These are constructed such that the water can be pumped out, keeping the working...

     are sunk and any soft bottom is excavated for a foundation. If the bedrock
    Bedrock
    In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

     is too deep to be exposed by excavation or the sinking of a caisson, pilings are driven to the bedrock or into overlying hard soil, or a large concrete pad to distribute the weight over less resistant soil may be constructed, first preparing the surface with a bed of compacted gravel. (Such a pad footing can also accommodate the movements of an active fault
    Active fault
    An active fault is a fault that is likely to have another earthquake sometime in the future. Faults are commonly considered to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years....

    , and this has been implemented on the foundations of the cable-stayed
    Cable-stayed bridge
    A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....

     Rio-Antirio bridge
    Rio-Antirio bridge
    The Rion-Antirion bridge , officially the Charilaos Trikoupis bridge after the statesman who first envisaged it, is the world's longest multi-span cable-stayed bridge...

    . The piers are then extended above water level, where they are capped with pedestal bases for the towers.
  2. Where the towers are founded on dry land, deep foundation excavation or pilings are used.
  3. From the tower foundation, towers of single or multiple columns are erected using high-strength reinforced concrete, stonework, or steel. Concrete is used most frequently in modern suspension bridge construction due to the high cost of steel.
  4. Large devices called saddles, which will carry the main suspension cables, are positioned atop the towers. Typically of cast steel, they can also be manufactured using riveted forms, and are equipped with rollers to allow the main cables to shift under construction and normal loads.
  5. Anchorages are constructed, usually in tandem with the towers, to resist the tension of the cables and form as the main anchor system for the entire structure. These are usually anchored in good quality rock, but may consist of massive reinforced concrete deadweights within an excavation. The anchorage structure will have multiple protruding open eyebolts enclosed within a secure space.
  6. Temporary suspended walkways, called catwalks, are then erected using a set of guide wires hoisted into place via winches positioned atop the towers. These catwalks follow the curve set by bridge designers for the main cables, in a path mathematically described as a catenary
    Catenary
    In physics and geometry, the catenary is the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight. The curve is the graph of the hyperbolic cosine function, and has a U-like shape, superficially similar in appearance to a parabola...

     arc. Typical catwalks are usually between eight and ten feet wide, and are constructed using wire grate and wood slats.
  7. Gantries are placed upon the catwalks, which will support the main cable spinning reels. Then, cables attached to winches are installed, and in turn, the main cable spinning devices are installed.
  8. High strength wire (typically 4 or 6 gauge galvanized steel wire), is pulled in a loop by pulleys on the traveler, with one end affixed at an anchorage. When the traveler reaches the opposite anchorage the loop is placed over an open anchor eyebar
    Eyebar
    In structural engineering and construction, an eyebar is a straight bar, usually of metal, with a hole at each end for fixing to other components...

    . Along the catwalk, workers also pull the cable wires to their desired tension. This continues until a bundle, called a "cable strand" is completed, and temporarily bundled using stainless steel wire. This process is repeated until the final cable strand is completed. Workers then remove the individual wraps on the cable strands (during the spinning process, the shape of the main cable closely resembles a hexagon), and then the entire cable is then compressed by a traveling hydraulic press into a closely packed cylinder and tightly wrapped with additional wire to form the final circular cross section. The wire used in suspension bridge construction is a galvanized steel wire that has been coated with corrosion inhibitors.
  9. At specific points along the main cable (each being the exact distance horizontally in relation to the next) devices called "cable bands" are installed to carry steel wire ropes called Suspender cables. Each suspender cable is engineered and cut to precise lengths, and are looped over the cable bands. In some bridges, where the towers are close to or on the shore, the suspender cables may be applied only to the central span. Early suspender cables were fitted with zinc jewels and a set of steel washers, which formed the support for the deck. Modern suspender cables carry a shackle-type fitting.
  10. Special lifting hoists attached to the suspenders or from the main cables are used to lift prefabricated sections of bridge deck to the proper level, provided that the local conditions allow the sections to be carried below the bridge by barge or other means. Otherwise, a traveling cantilever
    Cantilever
    A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...

     derrick may be used to extend the deck one section at a time starting from the towers and working outward. If the addition of the deck structure extends from the towers the finished portions of the deck will pitch upward rather sharply, as there is no downward force in the center of the span. Upon completion of the deck the added load will pull the main cables into an arc mathematically described as a parabola
    Parabola
    In mathematics, the parabola is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface...

    , while the arc of the deck will be as the designer intended — usually a gentle upward arc for added clearance if over a shipping channel, or flat in other cases such as a span over a canyon. Arched suspension spans also give the structure more rigidity and strength.
  11. With completion of the primary structure various details such as lighting, handrails, finish painting and paving are installed or completed.

The longest suspension bridge spans in the world


Suspension bridges are typically ranked by the length of their main span. These are the ten bridges with the longest spans, followed by the length of the span and the year the bridge opened for traffic:
  1. Akashi Kaikyō Bridge (Japan
    Japan
    Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

    ), 1991 m — 1998
  2. Xihoumen Bridge
    Xihoumen Bridge
    The Xihoumen Bridge The 5.3-kilometre-long suspension bridge connection has a 2.6-kilometre-long main bridge with a central span of 1,650 metres. The approaches total 2.7 kilometres. When it opened, there was only one bridge with a larger span, the Akashi-Kaikyo Bridge in Japan...

     (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...

    ), 1650 m — 2009
  3. Great Belt Bridge (Denmark
    Denmark
    Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...

    ), 1624 m — 1998
  4. Runyang Bridge (China), 1490 m — 2005
  5. Humber Bridge
    Humber Bridge
    The Humber Bridge, near Kingston upon Hull, England, is a 2,220 m single-span suspension bridge, which opened to traffic on 24 June 1981. It is the fifth-largest of its type in the world...

     (England, United Kingdom
    United Kingdom
    The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

    ), 1410 m — 1981. (The longest span from 1981 until 1998.)
  6. Jiangyin Suspension Bridge
    Jiangyin Suspension Bridge
    The Jiangyin Suspension Bridge was the most seaward bridge to cross the Yangtze River of China at the time of its completion, however, the recently completed Sutong Bridge and Shanghai Yangtze Bridge/Tunnel are now more seaward. It connects the cities of Jiangyin and Jingjiang...

     (China), 1385 m — 1997
  7. Tsing Ma Bridge
    Tsing Ma Bridge
    The Tsing Ma Bridge is a bridge in Hong Kong. It is the world's seventh-longest span suspension bridge, and was the second longest at time of completion. The bridge was named after two of the islands at its ends, namely Tsing Yi and Ma Wan . It has two decks and carries both road and rail...

     (Hong Kong
    Hong Kong
    Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

    , China), 1377 m — 1997 (longest span with both road and metro)
  8. Verrazano-Narrows Bridge
    Verrazano-Narrows Bridge
    The Verrazano-Narrows Bridge is a double-decked suspension bridge that connects the boroughs of Staten Island and Brooklyn in New York City at the Narrows, the reach connecting the relatively protected upper bay with the larger lower bay....

     (USA
    United States
    The United States of America is a federal constitutional republic comprising fifty states and a federal district...

    ), 1298 m — 1964. (The longest span from 1964 until 1981.)
  9. Golden Gate Bridge
    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...

     (USA), 1280 m — 1937. (The longest span from 1937 until 1964.)
  10. Yangpu Bridge
    Yangpu Bridge
    The Yangpu Bridge , in Shanghai, China,sister bridge to Nanpu Bridge, is among the world's longest bridges, with a total length of 8354 meters. Its longest span of 602 m makes it the fourth largest cable-stayed bridge in the world. It carries the Inner Ring Road from the Yangpu District in Puxi to...

     (China), 1280 m — 2007

Other suspended-deck suspension bridges

  • Brooklyn Bridge
    Brooklyn Bridge
    The Brooklyn Bridge is one of the oldest suspension bridges in the United States. Completed in 1883, it connects the New York City boroughs of Manhattan and Brooklyn by spanning the East River...

     (USA, 1883), The first steel-wire suspension bridge.
  • Bear Mountain Bridge
    Bear Mountain Bridge
    The Bear Mountain Bridge is a toll suspension bridge in New York State, carrying U.S. Highways 202 and 6 across the Hudson River between Rockland and Westchester counties...

     (USA, 1924), The longest suspension span (497 m)from 1924 to 1926. The first suspension bridge to have a concrete deck. The construction methods pioneered in building it would make possible several much larger projects to follow.
  • Ben Franklin Bridge (Philadelphia, PA, USA, 1926), Replaced Bear Mountain Bridge as longest span at 1,750 feet between the towers. Includes an active subway line and never-used trolley stations on the span.
  • John A. Roebling Suspension Bridge
    John A. Roebling Suspension Bridge
    The John A. Roebling Suspension Bridge spans the Ohio River between Cincinnati, Ohio and Covington, Kentucky. When the first pedestrians crossed on December 1, 1866, it was the longest suspension bridge in the world at 1,057 feet main span. Today, many pedestrians use the bridge to get between...

     (USA, 1866), Then the longest wire suspension bridge in the world at 1,057 feet (322 m) main span.
  • Mackinac Bridge
    Mackinac Bridge
    The Mackinac Bridge is a suspension bridge spanning the Straits of Mackinac to connect the non-contiguous Upper and Lower peninsulas of the U.S. state of Michigan. Opened in 1957, the bridge is the third longest in total suspension in the world and the longest suspension bridge between anchorages...

     (USA, 1957), The longest suspension bridge between anchorages in the Western hemisphere.
  • Roebling's Delaware Aqueduct
    Roebling's Delaware Aqueduct
    -External links:...

     (USA, 1847) The oldest wire suspension bridge still in service in United States.
  • Si Du River Bridge
    Si Du River Bridge
    The Si Du River Bridge is a long suspension bridge crossing the valley of the Si Du River near Yesanguan in Badong County of the Hubei Province of the People's Republic of China. The bridge was designed by CCSHCC Second Highway Consultants Company, Ltd. and built at a cost of 720 million yuan...

     (China, 2009), The highest bridge in the world (at least 472 meters).
  • San Francisco – Oakland Bay Bridge (USA, 1936), Until recently, this was the longest steel high-level bridge in the world (704 m). The eastern portion (a cantilever bridge
    Cantilever bridge
    A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...

    ) is being replaced with a self-anchored suspension bridge
    Self-anchored suspension bridge
    A self-anchored suspension bridge is a suspension bridge in which the main cables attach to the ends of the deck, rather than to the ground via large anchorages...

     which will be the longest of its type in the world.
  • Union Bridge
    Union Bridge (Tweed)
    The Union Bridge is a suspended-deck suspension bridge that spans the River Tweed between Horncliffe, Northumberland, England and Fishwick, Borders, Scotland...

     (England/Scotland, 1820), The longest span (137 m) from 1820 to 1826. The oldest in the world still in use today.

Infamous suspended-deck suspension bridges

  • The Bridge of San Luis Rey
    The Bridge of San Luis Rey
    The Bridge of San Luis Rey is American author Thornton Wilder's second novel, first published in 1927 to worldwide acclaim. It tells the story of several interrelated people who die in the collapse of an Inca rope-fiber suspension bridge in Peru, and the events that lead up to their being on the...

     (Fictional)
  • Silver Bridge
    Silver Bridge
    The Silver Bridge collapsed in 1967, killing 46 people. The terms Silver Bridge or Silverbridge may also refer to:* Silver Memorial Bridge, the replacement for the above bridge, opened in 1969....

    , Point Pleasant, West Virginia
    Point Pleasant, West Virginia
    Point Pleasant is a city in Mason County, West Virginia, United States, at the confluence of the Ohio and Kanawha rivers. The population was 4,637 at the 2000 census...

     - Eyebar chain highway bridge, built in 1928, that collapsed in late 1967, killing forty-six people.
  • Tacoma Narrows Bridge, (USA), 853 m — 1940. The Tacoma Narrows
    Tacoma Narrows
    The Tacoma Narrows , a strait, is part of Puget Sound in the U.S. state of Washington. A navigable maritime waterway between glacial landforms, the Narrows separates the Kitsap Peninsula from the city of Tacoma....

     bridge was vulnerable to structural vibration in sustained and moderately strong wind
    Wind
    Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

    s due to its plate-girder deck structure. Wind caused a phenomenon called aeroelastic fluttering that led to its collapse only months after completion. The collapse was captured on film.

See also

:Category:Suspension bridges — for articles about specific suspension bridges.
  • List of longest suspension bridge spans
  • Timeline of three longest spans
    Timeline of three longest spans
    This is the timeline of the 3 longest man-made spans in the world, all categories, that at least have the strength to carry some persons. It can be the span of any type of bridge, aerial tramway, powerline, structural ceiling or dome etc.- Overview :...

     whether 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...

    , aerial tramway
    Aerial tramway
    An aerial tramway , cable car , ropeway or aerial tram is a type of aerial lift which uses one or two stationary ropes for support while a third moving rope provides propulsion...

    , powerline
    Electric power transmission
    Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...

    , ceiling
    Ceiling
    A ceiling is an overhead interior surface that covers the upper limit of a room. It is generally not a structural element, but a finished surface concealing the underside of the floor or roof structure above....

     or dome
    Dome
    A dome is a structural element of architecture that resembles the hollow upper half of a sphere. Dome structures made of various materials have a long architectural lineage extending into prehistory....

     etc.
  • 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....

     — superficially similar to a suspension bridge, but cables from the towers directly support the roadway, rather than the road being suspended indirectly by additional cables from the main cables connecting two towers.
  • Inca rope bridge — has features in common with a suspension bridge and predates them by at least three hundred years. However in a rope bridge the deck itself is suspended from the anchored piers and the guardrails are non-structural.
  • Self-anchored suspension bridge
    Self-anchored suspension bridge
    A self-anchored suspension bridge is a suspension bridge in which the main cables attach to the ends of the deck, rather than to the ground via large anchorages...

     — combining elements of a suspension bridge and a cable-stayed bridge.
  • Simple suspension bridge
    Simple suspension bridge
    A simple suspension bridge is an early type of bridge that is supported entirely from anchors at either end, and has no towers or piers. However, it may have saddles...

    — a modern implementation of the rope bridge using steel cables, although either the upper guardrail or lower footboard cables may be the main structural cables.

External links

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