A suspension bridge
is a bridge
that consists of two pairs of pillars
, one on either end of the span, with two or more cables
slung between them. The bridge deck is suspended from vertical cables or rods attached to the main cables. The main cables continue beyond the pillars, and are anchored in the ground. The bridge also has two smaller spans, running between either pair of pillars and the land. The design was developed in the late 19th century
, and has become widely used since.
The main forces in a suspension bridge are the tension[?] in the main cables and the compression in the pillars. Since almost all the force on the pillars is vertically downwards, they can be made quite slender.
Two main reasons for building a suspension bridge, instead of, for instance, a cheaper low bridge, are:
- The center span may be made very long, allowing the bridge to span a very wide, deep rift, and
- It can be built high over water to allow the passage of very tall ships.
The largest suspension bridges in the world, by length of center span, are:
- Akashi-Kaikyo Bridge (Japan) 1,990 meters or 6,527 feet - 1991
- Great Belt Bridge (Denmark) 1,624 meters or 5,328 feet - 1998
- Humber Bridge (England) 1,410 meters or 4,624 feet - 1981
- Jangyn Bridge[?] (China, Yangtse River[?]) 1,385 meters - 1999
- Tsing Ma Bridge (Hong Kong) 1,377 meters - 1997
- Verrazano Narrows Bridge[?] (USA) 1,298 meters or 4,260 feet - 1964
- Golden Gate Bridge (USA) 1,280 meters or 4,200 feet - 1937
- Hoga Kusten[?] (Sweden) - 1,210 meters - 1997
- Mackinac Bridge (USA) 1,158 meters or 3,800 feet - 1957
- Minami Bisan-Seto Bridge (Japan) 1,118 meters or 3,668 feet - 1988
- Second Bosporus Bridge[?] (Turkey) 1,090 meters or 3,576 feet - 1988
- First Bosporus Bridge[?] (Turkey) 1,074 meters or 3,524 feet - 1973
- George Washington Bridge (USA) 1,067 meters or 3,500 feet - 1931
- Third Kurushima-Kaikyo Bridge (Japan) 1,030 meters - 1999
- Second Kurushima-Kaikyo Bridge (Japan) 1,020 meters - 1999
A bridge with a center span of 3,290 m or 10,800 feet is proposed to connect Italy and Sicily but construction has not yet begun. Another has been proposed for the Strait of Gibraltar.
Other famous suspension bridges are:
See also: cable-stayed bridge
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