Underspanned suspension bridge
Encyclopedia
An underspanned suspension bridge (also upper deck suspension bridge) is a rare type of suspension bridge
that was developed in the early 19th century. It differs from its ancestor, the simple suspension bridge
, in that the deck is raised on posts above the main cables. The raised deck is less stable than a deck laid on or hung below the cables, and very few underspanned suspension bridges have been built. Examples include Guillaume Henri Dufour
's Pont des Bergues (1834); and James Smith’s Micklewood Bridge. Similar bridges were proposed by Robert Stevenson
in 1820 for a bridge over the River Almond between Edinburgh
and Queensferry, and by a Mr. Armstrong for a bridge at Clifton. Part of the roadway on the land side of the piers of the Hammersmith Bridge
was constructed in this manner. In the late 19th century and into the 20th century a few bridges of this type were constructed.
The Micklewood Bridge, constructed at Doune
in Scotland
, was the very first of this type. It had a span
of 103 feet, and the main cables were chains, making this an instance of a chain bridge. The deck was stiff and relatively stable, owing to heavy cross-braces.
Suspension bridge
A suspension bridge is a type of bridge in which the deck 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...
that was developed in the early 19th century. It differs from its ancestor, the 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...
, in that the deck is raised on posts above the main cables. The raised deck is less stable than a deck laid on or hung below the cables, and very few underspanned suspension bridges have been built. Examples include 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 Pont des Bergues (1834); and James Smith’s Micklewood Bridge. Similar bridges were proposed 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:...
in 1820 for a bridge over the River Almond between 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...
and Queensferry, and by a Mr. Armstrong for a bridge at Clifton. Part of the roadway on the land side of the piers of the Hammersmith Bridge
Hammersmith Bridge
Hammersmith Bridge is a crossing of the River Thames in west London, just south of the Hammersmith town centre area of the London Borough of Hammersmith and Fulham on the north side of the river. It allows road traffic and pedestrians to cross to Barnes on the south side of the river...
was constructed in this manner. In the late 19th century and into the 20th century a few bridges of this type were constructed.
The Micklewood Bridge, constructed at Doune
Doune
Doune is a burgh in the district of Stirling, Scotland, on the River Teith. Doune's postal address places the town in Perthshire, although geographically it lies within the District of Stirling, and administratively Doune is under the control of Stirling Council...
in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
, was the very first of this type. It had a span
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...
of 103 feet, and the main cables were chains, making this an instance of a chain bridge. The deck was stiff and relatively stable, owing to heavy cross-braces.