Jump to content

Severn Bridge

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 69.177.150.49 (talk) at 22:10, 2 May 2007 (Location). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Severn Bridge
The Severn Bridge seen from the English side of the river. From 1966 to 1996, the bridge carried the M4 motorway. On completion of the Second Severn Crossing the motorway from Aust on the English side to Rogiet was renamed the M48
Coordinates51°36′36″N 2°38′25″W / 51.6099°N 2.64026°W / 51.6099; -2.64026
Carries6 lane M48 motorway
CrossesSevern Estuary
LocaleSouth West England/South East Wales
Characteristics
Designsuspension bridge
Longest span3240ft (988m)
History
Opened8 September 1966
Statistics
TollCar: £5.10
HGV: £15.30
Motorcycle: Free
Location
Map
For the Ontario community, see Severn Bridge, Ontario.

The Severn Bridge (Welsh: Pont Hafren) is a suspension bridge that spans the River Severn from South Gloucestershire, just north of Bristol, to Monmouthshire in south Wales, via Beachley, a peninsula between the Severn and Wye estuaries. It is the original Severn crossing between England and Wales and took five years to construct at a cost of £8 million. The bridge was opened on 8 September 1966 by Queen Elizabeth II, who hailed it as the dawn of a new economic era for South Wales. The bridge was granted Grade I listed status in 1998.[1]

Location

Although the Severn Bridge can only be used for crossing between England and Wales, it is located wholly within England. This is because the "Welsh" end of the bridge itself is located above the Beachley peninsula, which modern boundaries place in England. The border with Wales bissects the Wye bridge, slightly further north along the route.

The ancient Offa's Dyke placed the Beachley peninsula in Wales.

tits

Component structures

The Severn Bridge crossing consists of several structures, which, listed in order from England to Wales, are: the Aust Viaduct, Severn Bridge, Beachley Viaduct and Wye Bridge.

Aust Viaduct

The Aust Viaduct is a twin box girder structure with a concrete deck, which carries the roadway to the first gravity anchorage of the old Severn Bridge. The roadway is then carried over the top of the concrete anchorage to the Severn Bridge.

Severn Bridge

Severn Bridge looking north, Jan 2006

The Severn Bridge is located close to the former Aust Ferry. The bridge is a 5240 feet (1597 metres) long suspension bridge of conventional design, with the deck supported by two main cables slung between two steel towers. The length of the central span (between the towers) is 3240 feet (988 m). The towers rise to 445 feet (136 m) above mean high water and are of hollow box construction. The deck is an orthotropic steel box girder of aerofoil shape with cantilevered cycle tracks and footway supported from the box. The shape of the bridge was determined by the designers Freeman, Fox and Partners following wind tunnel tests for the Forth Road Bridge, after the original wind tunnel model was accidentally destroyed. The sections of the deck were built at Fairfield-Mabey in Chepstow, each 132 tonne section was then floated down the river before being hoisted into position.

Beachley Viaduct

The Beachley Viaduct is also of similar box girder construction as the Severn Bridge but is supported on steel trestles as it crosses the Beachley peninsula. The peninsula contains an army camp, which the bridge crosses.

Wye Bridge

The Wye Bridge is a 1340 ft (408 m) long cable-stayed bridge, which crosses the border marked by the River Wye into Wales, 3 km south of Chepstow. It consists of a single large cable stayed section with two single-leg pylons supporting the bridge deck from the centre of the roadway. The deck is an orthotropic box girder similar to the Severn Bridge but has a different appearance as it has two sets of cable stays on each of two towers (originally there was only one set of cable stays but these were replaced during the strengthening works in the late 1980s).

Post-construction changes

The Severn Bridge crossing was strengthened and resurfaced in the late 1980s as the weight of traffic grew. The work included the strengthening of the Severn Bridge towers and deck, an extension to the existing Wye Bridge towers and the replacement of the original single stays with two stays. The open structure of the new stays is designed to facilitate maintenance. Most of the strengthening work was inside the deck box or towers and so is not visible. The surfacing is a thin layer (about 35 mm) of mastic asphalt over an acrylic waterproofing membrane.

The road is only two carriageways of two lanes in each direction, and as traffic volumes grew it became a major bottleneck. At its peak, it was carrying 50 000 vehicles a day. The burden of maintenance also became unmanageable, so that by the 1990s a second Severn crossing was necessary. Since the construction of the second bridge, the original crossing carries 15 000 vehicles day, 25% of the total traffic traversing the estuary.

Toll

Shortly after the opening of the Severn Bridge, Anglo-Welsh poet Harri Webb wrote an Ode on the Severn Bridge:[2]

Two lands at last connected
Across the waters wide,
And all the tolls collected
On the English side.

The toll is indeed collected on the English side, and only on vehicles travelling westwards from England to Wales, leading some people describing it as a "tax on entering Wales", both in jest, and also as a more serious anti-toll campaign.[3] Originally, tolls were charged in both directions, but the arrangements were changed in the early 1990s to eliminate the need for a set of toll booths for each direction of travel and the potential for traffic waiting to pay the toll backing up onto the bridge itself.

As of January 2007, the toll is £5.10 for a car, increasing to £15.30 for a heavy goods vehicle. Motorcycles and disabled badge holders are exempt from the tolls, although both must stop at the toll booths to have their eligibility confirmed. The tolls for the Second Severn Crossing are the same (although in this case, the tolls are collected on the Welsh side, the longer approach viaducts making queueing on the bridge less of an issue). A system known as the Severn TAG made by Amtech is also in operation, which allows drivers to pay electronically without having to stop at the toll booths. TAGs are available either on a per-trip or a seasonal basis, although only the latter attracts a discount.[4] The cycle path and footpath, which run along either side of the roadway, may be used free of charge.

Trivia & Myths

The bridge won a Civic Trust Award for 1968
  • It is often claimed that in the movie Star Wars (1977), "the sounds of the lasers were made by striking one of the suspension wires of the original Severn Bridge. The longer ones were used for the ships while the shorter ones were used for the hand guns."[5] This is untrue and Ben Burtt the Sound Designer for Star Wars describes the actual location used on the Filmsound website.[6]
  • For the rock band Marillion's album Brave (1994), singer Steve Hogarth used a concept that was inspired by a radio broadcast from the Bristol Police. Quoting Steve Hogarth: "The police had picked up a young woman wandering on the Severn Bridge who refused or was unable to speak to them. In desperation the appeal was broadcast to the general public in an attempt to discover her identity." Hogarth heard it on the radio, and several years later it inspired him while he and the band were working on what was to become the Brave album.[7]
  • On 1 February 1995, Richey James Edwards, the former guitarist and key lyricist for the Welsh based rock band Manic Street Preachers disappeared and was never seen again. Though it has been debated whether or not the musician, who had a well-documented history of self-harm, took his own life, his car was found several days later in a motorway service station near the Severn Bridge, which has since its construction acquired notoriety for being a suicide spot.

40 Year old - Inspections

During its 40th year of operation, inspection frames have appeared on the Severn Crossing, with a view to checking corrosion on the cabling of the bridge. According to the BBC[8] and the Highways Agency,[9] the inspection has concluded that the bridge needs to have restrictions on heavy goods vehicles. A system of installing a rubber casing on the cables with dry air circulation is to be used on the Forth Road Bridge and a similar system may be implemented on the Severn Bridge, in a move to halt the progress of the corrosion.[10]

Severn Bridge panorama, 2002

See also

References

  1. ^ "Severn Bridge and Aust Viaduct". Images of England. Retrieved 2006-12-22.
  2. ^ Ode on the Severn Bridge quoted in the House of Lords Hansard, 17 February 1999
  3. ^ Road toll activist calls on Zeta, The Western Mail, 31 August 2004
  4. ^ Current toll prices, Severn River Crossing PLC
  5. ^ Star Wars trivia at the Internet Movie Database.
  6. ^ Star Wars Sound Effects at the Film Sound website
  7. ^ Brave, Marillion's official website
  8. ^ HGVs curbed on old Severn Bridge From BBC News
  9. ^ Highways Agency Press Release
  10. ^ Severn Bridge's corrosion problem BBC, 9 March

Pictures

51°36′33″N 2°38′18″W / 51.609030°N 2.638376°W / 51.609030; -2.638376