The taper suspension bridge (also known as the taper principle) is a bridge design patented by James Dredge in 1836. [1]
On a conventional suspension bridge, the whole deck is suspended by vertical cables, rods or chains from a single cable or chain slung between two supporting towers. The taper suspension bridge, devised by James Dredge in the early nineteenth century, differs from the conventional suspension bridge design in that it effectively functions as a double cantilever bridge. Each opposing cantilever system is self-supporting. The cantilever half-deck structure of each cantilever is suspended from angled chains, which hang from a tapered main attached to the top of the tower and to the outer end of the half-deck. The main chain taper is achieved by incrementally reducing the number of links stacked across the chain's width as it moves farther from the support tower. [2]
The advantage of this taper system is that it results in a more cost-effective design compared to conventional suspension bridge of the time because it uses less iron and is quicker to build. [1]
Of the 36 known examples of bridges started or completed by Dredge using this design, 7 are known to have survived. [1]
Name | Date built | Original location | Current location | Span | Image |
---|---|---|---|---|---|
Victoria Bridge | 1836 | Bath, England | As built | 150 feet (46 m) | |
Glenarb Bridge | 1844 | River Blackwater, Caledon, Northern Ireland | Relocated to Caledon [3] | ||
Caledon Estate Bridge | 1845 | River Blackwater, Caledon, Northern Ireland | As built | ||
Stowell Park Bridge | 1845 | Pewsey, Wiltshire, England | As built | ||
Second Moyola Park Bridge | 1847 | Castledawson, Northern Ireland | As built | ||
Bridge of Oich | 1854 | River Oich, Aberchalder, Scotland | As built | 155 feet 6 inches (47.40 m) [2] | |
General's Well Bridge [4] | 1853 [5] | River Ness, Ness Islands. Inverness [4] | Relocated to Ness Islands Railway, Whin Park, Inverness | 97 feet (30 m) [4] |
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridges, which lack vertical suspenders, have a long history in many mountainous parts of the world.
The Clifton Suspension Bridge is a suspension bridge spanning the Avon Gorge and the River Avon, linking Clifton in Bristol to Leigh Woods in North Somerset. Since opening in 1864, it has been a toll bridge, the income from which provides funds for its maintenance. The bridge is built to a design by William Henry Barlow and John Hawkshaw, based on an earlier design by Isambard Kingdom Brunel. It is a Grade I listed building and forms part of the B3129 road.
A cable-stayed bridge has one or more towers, from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly.
Chelsea Bridge is a bridge over the River Thames in west London, connecting Chelsea on the north bank to Battersea on the south bank, and split between the City of Westminster, the London Borough of Wandsworth and the Royal Borough of Kensington and Chelsea. There have been two Chelsea Bridges, on the site of what was an ancient ford.
The Menai Suspension Bridge is a suspension bridge spanning the Menai Strait between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it was the world's first major suspension bridge. The bridge still carries road traffic and is a Grade I listed structure.
The Conwy Suspension Bridge is a Grade I-listed structure and is one of the first road suspension bridges in the world. Located in the medieval town of Conwy in Conwy county borough, North Wales, it is now only passable on foot. The bridge is now in the care of the National Trust. It originally carried the A55(T) road from Chester to Bangor.
A simple suspension bridge is a primitive type of bridge in which the deck of the bridge lies on two parallel load-bearing cables that are anchored at either end. They have no towers or piers. The cables follow a shallow downward catenary arc which moves in response to dynamic loads on the bridge deck.
The eastern span replacement of the San Francisco–Oakland Bay Bridge was a construction project to replace a seismically unsound portion of the Bay Bridge with a new self-anchored suspension bridge (SAS) and a pair of viaducts. The bridge is in the U.S. state of California and crosses the San Francisco Bay between Yerba Buena Island and Oakland. The span replacement took place between 2002 and 2013, and is the most expensive public works project in California history, with a final price tag of $6.5 billion, a 2,500% increase from the original estimate of $250 million, which was an initial estimate for a seismic retrofit of the span, not the full span replacement ultimately completed. Originally scheduled to open in 2007, several problems delayed the opening until September 2, 2013. With a width of 258.33 ft (78.74 m), comprising 10 general-purpose lanes, it is the world's widest bridge according to Guinness World Records.
The Three Sisters are three similar self-anchored suspension bridges spanning the Allegheny River in downtown Pittsburgh, Pennsylvania at 6th, 7th, and 9th streets, generally running north–south. The bridges have been given formal names to honor important Pittsburgh residents:
Chepstow Railway Bridge was built to the instructions of Isambard Kingdom Brunel in 1852. The "Great Tubular Bridge" over the River Wye at Chepstow, which at that point forms the boundary between Wales and England, is considered one of Brunel's major achievements, despite its appearance. It was economical in its use of materials, and would prove to be the design prototype for Brunel's Royal Albert Bridge at Saltash. Although the superstructure has since been replaced, Brunel's tubular iron supports are still in place. It is a Grade II listed structure.
A suspension bridge supports its structural load 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.
A tied-arch bridge is an arch bridge in which the outward-directed horizontal forces of the arch(es) are borne as tension by a chord tying the arch ends rather than by the ground or the bridge foundations. This strengthened chord may be the deck structure itself or consist of separate, independent tie-rods.
Dryburgh Abbey Bridge was a cable-stayed footbridge of significant historical interest erected near Dryburgh Abbey, in the Borders of Scotland. It connected the villages of Dryburgh and St. Boswells, across the River Tweed. A crossing had existed here for centuries, originally with a ferry service.
The Salford Quays lift bridge, also known as the Salford Quays Millennium footbridge or the Lowry bridge, is a 91.2-metre (299 ft) long vertical lift bridge spanning the Manchester Ship Canal between Salford and Trafford in Greater Manchester, England. The pedestrian bridge, which was completed in 2000, is near the terminus of the ship canal at the old Manchester Docks. It is sited beside The Lowry theatre and gallery and links Salford Quays and MediaCityUK to Trafford Wharf and the Imperial War Museum North. It has a lift of 18 metres (59 ft), allowing large watercraft to pass beneath.
Victoria Bridge in Bath, England, was built in 1836 across the River Avon. The bridge has been recognised as a Grade II* listed building.
James Dredge (1794–1863) was an English civil engineer, architect and brewer. He was born in Bath and was a brewer by trade for much of his life. He designed over 50 bridges and piers in his later years, such as the Victoria Bridge in Bath in 1836, and the Birnbeck Pier in Weston-super-Mare in 1845.
The Dongshuimen Bridge and the Qiansimen Bridge, known collectively as the Twin River Bridges, are a pair of bridges that form a road and rail connection in Chongqing, China. Consisting of two cable-stayed bridges and a tunnel across the Yuzhong peninsula where the heart of Chongqing's commercial & financial district Jiefangbei CBD is located, the connection opened in 2014.
The Bridge of Oich is a taper principle suspension bridge, designed by James Dredge, across the River Oich near Aberchalder in Highland, Scotland. The bridge opened in 1854 and was used to take the main road traffic over the river until 1932.
The Long Gully Bridge, also known as Northbridge, Suspension Bridge, and Cammeray Bridge, is a concrete arch road bridge that carries Strathallen Avenue across Flat Rock Creek and Tunks Park, and connects the suburbs of Cammeray, in the North Sydney Council local government area to its south, with Northbridge in the City of Willoughby local government area to its north, in Sydney, New South Wales, Australia.
A suspended structure is a structure which is supported by cables coming from beams or trusses which sit atop a concrete center column or core. The design allows the walls, roof and cantilevered floors to be supported entirely by cables and a center column.