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.

Suspension types

The suspension in older bridges may be made from chain or linked bars, but modern bridge cables are made from multiple strands of wire. This is for greater redundancy; a few flawed strands in the hundreds used pose very little threat, whereas a single bad link or eyebar can eliminate the safety margin or bring down the structure outright.

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