Tinsley Viaduct

Infobox Bridge
bridge_name=Tinsley Viaduct

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caption=Tinsley Viaduct as seen from Meadowhall, with the two cooling towers of the former Blackburn Meadows power station prior to their demolition in 2008.
official_name=
carries=M1, A631
crosses=River Don
Sheffield Canal
Midland Main Line
South Yorkshire Railway
locale=Tinsley/Wincobank
maint=Highways Agency
id=
design=twin deck box girder bridge [cite web|url=http://www.highways.gov.uk/roads/projects/6028.aspx|title=Tinsley Viaduct|publisher=Highways Agency]
mainspan=50 m / 163 feet (20 spans)
length=1,033m / 3,400 feet
width=6 lanes
height=m to ft|abbr=no|spell=Commonwealth|20 (to upper level)
load=
clearance=m to ft|abbr=no|spell=Commonwealth|10 (on the A631)
below=m to ft|abbr=no|spell=Commonwealth|10 metres [cite web|url=http://www.safespanplatforms.com/news.html|title=Safespan's Latest News|Publisher=Safespan Inc.]
traffic=100,000 vehicles/day [cite web|url=http://www.betterpublicbuildings.gov.uk/finalists/2005/tinsley/|title=Tinsley viaduct strengthening project, Sheffield|publisher=Prime Minister's Award]
begin=Spring 1965cite web|url=http://www.iht.org/motorway/m1bridges.htm|title=M1 Aston-Sheffield-Leeds|publisher=The Motorway Archive Trust]
complete=1968
open=25 March 1968
closed=
toll=
map_cue=
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map_text=
map_width=
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lat=
long=

Tinsley Viaduct is a two-tier road bridge in Sheffield, England; the first of its kind in the UK. It carries the M1 and the A631 1033 metres over the Don Valley, from Tinsley to Wincobank, also crossing the Sheffield Canal, the Midland Main Line and the former South Yorkshire Railway line from Tinsley Junction to Rotherham Central. The Supertram route to Meadowhall runs below part of the viaduct on the trackbed of the South Yorkshire Railway line to Barnsley.

History

The viaduct was opened in March 1968 [cite web|url=http://www.irsociety.co.uk/Archives/23/Tinsley.htm|title=Tinsley Viaduct, Sheffield|first=Sydney A.|last=Leleux|month=February|year=1969] and cost £6 million to build. The structure is unusual in that it is built as steel box girders, at a time when most long span bridges were being built of post tension concrete deck design. This use of steel has allowed the viaduct to be strengthened, in 1983 and again in 2006. The recent works to strengthen the bridge were a very complex operation, with a lot of the work happening inside the Box beam spine. The works took over 3 years and cost £82 million (14 x the original bridge building cost).

Although originally designed to carry 6 lanes, during the strengthening work the M1 was permanently reduced to 4 lanes following an EU directive on load bearing capacity to allow for the introduction of 40 ton trucks in the UK. This arrangement allows the third lane in each direction to join from J34 to make the very busy junction safer. [cite web|url=http://www.gnn.gov.uk/content/detail.asp?NewsAreaID=2&ReleaseID=172690|title=£82 Million M1 Tinsley Viaduct strengthening work nears completion|date=2005-10-10|publisher=Highways Agency]

The viaduct is balanced on rollers to allow for thermal expansion and contraction, and the route weaves slightly in order to make its way past obstacles. The viaduct due to its construction is very flexible and when sat on the lower deck you can feel it sway as the traffic passes overhead. The Meadowhall Shopping Centre lies in the valley to the west, while to the east is the Blackburn Meadows sewage works.

Tinsley cooling towers

The viaduct is one of Sheffield's most prominent landmarks, and was once made all the more so by the adjacent pair of cooling towers that were left standing for safety reasons after the demolition of the Blackburn Meadows power station. The cooling towers were a major point of contention over the years, and were once only saved from destruction after being chosen as a nesting site by a rare bird.Fact|date=August 2008 More recently, plans were made to turn them into a piece of public art. [cite news |url=http://news.bbc.co.uk/1/hi/uk/5160214.stm |title=Turning towers into art |work=BBC News |publisher=BBC |date=8 July 2006] Other plans for the towers included concert halls, skate parks and a theme park.

Their iconic status, and the possibly prohibitive costs of demolishing the towers safely, until recently looked to have cemented their status in Sheffield's future as much as they were a part of its history, until the owner of the tower (and the now-demolished power station) E.ON UK, stated its intention to demolish them once the strengthening of the viaduct made it feasible. [cite web|url=http://pressreleases.eon-uk.com/blogs/eonukpressreleases/archive/2008/08/12/1268.aspx|title=August demolition date set for Tinsley cooling towers|date=2008-08-12|publisher=E.ON UK]

The convert|250|ft|m|0 towers were demolished at 0300 BST on 24 August 2008 though a significant portion of the north tower remained standing for a short while. The demolition attracted widespread attention. A viewing platform was set up so the public could watch the demolition. [cite news |title=Blast demolishes landmark towers |url=http://news.bbc.co.uk/1/hi/england/south_yorkshire/7578266.stm |work=BBC News |publisher=BBC |date=24 August 2008 |accessdate=2008-08-24 ] Part of the site is proposed to be used for a new biomass power station by the owners E.ON UK. [cite web |url=http://eon-uk.com/generation/1490.aspx |title=E.ON UK Blackburn Meadows Green powerstation |accessdate=2008-08-24 |work= |publisher=E.ON |date= ]

ee also

*List of bridges in the United Kingdom

References

External links

* [http://www.betterpublicbuildings.gov.uk/finalists/2005/tinsley/ Project website] Prime Minister's Award
* [http://www.dontgo.co.uk/cooling.html Go sheffo: Cooling the Towers] Cooling towers public art competition held in 2005.
* [http://www.level-two.co.uk/adventure.php?a=giants Standing on the Shoulders of Giants] Blackburn Meadows cooling tower climb
* [http://www.itvlocal.com/yorkshire/news/?void=226856 Video of the demolition of the Cooling Towers] , ITV Local Yorkshire