The Adam Viaduct is a grade II listed concrete underbridge in Wallgate,

Wigan Wigan ( ) is a town in Greater Manchester, England. The town is midway between the two cities of Manchester, to the south-east, and Liverpool, to the south-west. It is the largest settlement in the Metropolitan Borough of Wigan and is its ad ...

. The bridge, constructed in 1946, is the earliest 'post-tensioned'

prestressed concrete Prestressed concrete is a form of concrete used in construction. It is substantially prestressed (Compression (physics), compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. Post-t ...

railway bridge in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, with only some examples in

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

being earlier. It is bridge number 54 on the

Kirkby branch line The Kirkby Branch Line is a branch railway line from Wigan to Headbolt Lane. The line's original route was from Liverpool to Bury, Greater Manchester, Bury and later the most northern of the Liverpool to Manchester lines. The line was split at ...

and is at a line distance of .

History and construction

The bridge was constructed as a

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, to see if prestressed concrete construction was feasible for rail projects in the UK, by the LMS railway company, and designed by their chief civil engineer

William Kelly Wallace William Kelly Wallace CBE (1883–1969) was an Irish railway engineer who joined the Northern Counties Committee and later became Chief Civil Engineer of the London Midland and Scottish Railway (LMS). He was awarded a civil CBE in the 1946 ...

. The beams used were prestressed using the Freyssinet system, in which concrete is precast with stressed high-tensile-strength metal tendons, which consist of multiple steel wires, running down the length of them. In construction, the beams internal rods are tightened and tied together so, under live load, they act as one. The LMS developed this system in the 1930s, and prestressed beams were first used for emergency repairs during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, but the Adam Viaduct first to use them for a full-scale project. The benefits of the system were found to be that it was quicker to install, more economical and longer-lasting, and with the bridge being less lively than traditional designs. The bridge has six

I-beams An I-beam is any of various structural members with an - (serif capital letter 'I') or H-shaped cross-section. Technical terms for similar items include H-beam, I-profile, universal column (UC), w-beam (for "wide flange"), universal beam (UB), ...

for each track and two beams for each

parapet A parapet is a barrier that is an upward extension of a wall at the edge of a roof, terrace, balcony, walkway or other structure. The word comes ultimately from the Italian ''parapetto'' (''parare'' 'to cover/defend' and ''petto'' 'chest/brea ...

, and they are deep. It was erected in 1946 on the foundations of an earlier

Victorian Victorian or Victorians may refer to: 19th century * Victorian era, British history during Queen Victoria's 19th-century reign ** Victorian architecture ** Victorian house ** Victorian decorative arts ** Victorian fashion ** Victorian literatur ...

bridge, created as part of the

Liverpool & Bury Railway The Liverpool and Bury Railway was formed by an act of Parliament in 1845 to link Liverpool and Bury via Kirkby, Wigan and Bolton, the line opening on 20 November 1848. The line became the Lancashire and Yorkshire Railway's main line between ...

in 1847, which was made from

timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

with masonry

abutments An abutment is the Bridge#Structure types, substructure at the ends of a bridge Span (architecture), span or dam supporting its Bridge#Structure types, superstructure. Single-span bridges have abutments at each end that provide vertical and l ...

. The earlier bridge was strengthened three times in: 1869, 1888 and 1906.

Southgate

Southgate, a bypass of the A49 from Pottery Road and Saddle Junction, passes underneath the bridge and next to the River Douglas. The road, which officially opened in March 2013, was constructed to reduce traffic in the area.

References

External links

Pre-stressed Concrete Railway StructuresHistory of Concrete Bridges
{{Authority control Grade II listed bridges in Greater Manchester Buildings and structures in Wigan