A
suspension bridge
A suspension bridge is a type of bridge in which the deck (bridge), deck is hung below suspension wire rope, cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridg ...
supports its
structural load
A structural load or structural action is a mechanical load (more generally a force) applied to Structural engineering#Structural elements, structural elements. A load causes stress (physics), stress, deformation (engineering), deformation, displa ...
with cables, ropes, or chains anchored at each end. Cables on the earliest suspension bridges were anchored in the ground; some modern suspension bridges anchor the cables to the ends of the bridge itself. Earliest suspension bridges had no towers or piers but the majority of larger modern suspension bridges have them.
All of the
14 longest bridges in the world are suspension bridges.
Types
Types of suspension bridge include:
A pure suspension bridge is one without additional stay cables and in which the main cables are anchored in the ground.
This includes most simple suspension bridges and suspended-deck suspension bridges, and excludes self-anchored suspension bridges.
Hybrid types
Some suspension bridges are of unusual hybrid types. Among these are suspension bridges that have an "intermediate deck".
[ pages 517-520] These bridges have a portion of deck that resembles an underspanned suspension bridge. Some of the earliest suspended-deck suspension bridges were of this type, and they continue to be constructed. Examples constructed in the 20th century include a viaduct over the river Oberargen near Wangen, Germany. A
span of the viaduct has a cable support below the deck, with one end of the cable anchored at a pier and the other end tied into a conventional cable stay. The underspanned portion of the span is long and has three vertical members.
The
Akashi Kaikyō Bridge
The is a suspension bridge that links the city of Kobe on the Japanese island of Honshu and on Awaji Island. It is part of the Kobe-Awaji-Naruto Expressway, and crosses the busy and turbulent Akashi Strait (''Akashi Kaikyō'' in Japanese). ...
, one of the longest suspension bridges in the world, is a suspended-deck suspension bridge with a stiff
truss girder deck.
Its main
span is long.
Construction
Unlike other types of bridge, suspension bridges can usually be built without use of
falsework
Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary ...
or even any access from below the bridge. In many cases, the main cables are constructed first, often with a ''pilot cable''. Construction then proceeds by hanging components and equipment from the main cables. The articles about each type of bridge have further specific construction details.
Suspension bridges are suitable for the longest spans, provided the cables and their anchorage are of sufficient
strength
Strength may refer to:
Personal trait
*Physical strength, as in people or animals
*Character strengths like those listed in the Values in Action Inventory
*The exercise of willpower
Physics
* Mechanical strength, the ability to withstand ...
. Their construction cost is high, so usually they are less economical than other bridges for spans less than . However, shorter spans have been constructed for aesthetic reasons.
All types of suspension bridges have less
rigidity than other bridges. Because of their greater flexibility, these bridges are more suitable as
road bridge
A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...
s than railroad bridges.
[ page 15.7]
See also
* (bridges made of living plants)
*
Cable-stayed bridge
A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which wire rope, cables support the bridge deck. A distinctive feature are the cables or wikt:stay#Etymology 3, stays, which run directly from the tower to the deck, norm ...
*
Floating suspension bridge
References
External links
"Suspension bridge"''Encyclopædia Britannica''
{{Set index article
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Bridges by structural type