Suspension bridge

A suspension bridge is a type of bridge that has been made since ancient times. Simple suspension bridges, for use by pedestrians, are still constructed in some places worldwide for use by pedestrians and livestock using designs based upon the ancient Inca rope bridge. Suspended from two high locations over a river or canyon, simple suspension bridges follow a shallow downward arc and are not suited for modern roads and railroads. Over the centuries, advancements in materials and design led to the development of the suspended-deck suspension bridge, a modern bridge capable of carrying vehicles and light rail. Instead of the deck following a downward arc of the main load bearing cables (or chains) these cables are suspended between towers and the cables support vertical suspender cables to carry the weight of a deck below, upon which the traffic crosses. This arrangement allows the deck to be level or to arc slightly upward for additional clearance.

The largest suspension bridges in the world

:main article: List of largest suspension bridges

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

When a suspension bridge is called "the largest", it typically means that the length of the main span is the longest. The record is currently held by the Akashi-Kaikyo Bridge in Japan. Ranking by the largest span does not mean that a bridge is longer from end to end or even the more massive, but it is a reasonably good indicator of the overall engineering achievement. The following is a list of the 15 largest suspension bridges ranked by length of center span.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• Akashi-Kaikyo Bridge (Japan) 1,991 m - 1998
• Great Belt Bridge (Denmark) 1,624 m - 1998
• Runyang Bridge (China) 1,490 m - 2005
• Humber Bridge (England) 1,410 m - 1981 (The largest from 1981 until 1998.)
• Jiangyin Suspension Bridge (China) 1,385 m - 1997
• Tsing Ma Bridge (Hong Kong) 1,377 m - 1997 (with road and metro)
• Verrazano Narrows Bridge (USA) 1,298 m - 1964 (The largest from 1964 until 1981.)
• Golden Gate Bridge (USA) 1,280 m - 1937 (The largest from 1937 until 1964.)
• Höga Kusten Bridge (Sweden) - 1,210 m - 1997
• Mackinac Bridge (USA) 1,158 m - 1958
• Minami Bisan-Seto Bridge (Great Seto Bridge) (Japan) 1,118 m - 1988
• Second Bosporus Bridge (Turkey) 1,090 m - 1988
• First Bosporus Bridge (Turkey) 1,074 m - 1973
• George Washington Bridge (USA) 1,067 m - 1931 (The largest from 1931 until 1937.)

It is also possible to rank suspension bridges by the total length of suspension. Note that some of these bridges have more than two towers, but these are actually multiple bridges. Having more than two towers without a central anchorage could be unstable in some conditions. A modern exception to this is the Chacao Channel bridge, currently under construction. This innovative bridge will have two main spans, made possible by the use of a rigid central tower composed of two side-by-side A frames. The stiffness of these frames (as opposed to the flexibility of the usual spar tower) prevents transmission of significant dynamic forces between the mainspans, ensuring dynamic stability in various wind conditions.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• Akashi-Kaikyo Bridge (Japan) 3,909 m
• Kurushima-Kaikyo Bridge (Japan) 3,260 m (suspended sections are not all contiguous)
• Great Seto Bridge (Japan) 3,186 m (two bridges with common anchorage)
• San Francisco-Oakland Bay Bridge (USA) 2,822 m (two bridges with common central anchorage)
• Great Belt Bridge (Denmark) 2,719 m
• Mackinac Bridge (USA) 2,625 m

The Strait of Messina Bridge, with a center span of 3,300 m, is planned to connect Italy and Sicily but construction has not yet begun. Bridges have also been suggested for the Strait of Gibraltar and the Sunda Strait with longest spans of several kilometres. The suspension cables for these longest bridges are suspended from the ends of cable-stayed struts extending diagonally from tall pylons.

Related Topics:
Strait of Messina Bridge - Italy - Sicily - Strait of Gibraltar - Sunda Strait - Kilometres

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~