Thelwall Viaduct | |
|---|---|
 Main span of the two bridges over theManchester Ship Canal, with the older bridge in the foreground | |
| Coordinates | 53°23′26″N2°30′21″W / 53.3906°N 2.5059°W /53.3906; -2.5059 |
| Carries |  M6 |
| Crosses | Manchester Ship Canal River Mersey |
| Locale | Lymm/Woolston,Cheshire |
| Maintained by | National Highways |
| Characteristics | |
| Design | Plate girder bridge |
| Material | Reinforced concrete,Steel |
| Total length | 4,414 ft (1345.4 m) northbound 4,500 ft (1371.6 m) southbound |
| Longest span | 336 ft (102.4 m) |
| Clearance below | 93 ft (28.3 m) |
| No. oflanes | 4 each direction Slip road on the northbound descent |
| History | |
| Constructed by | Leonard Fairclough (1963) |
| Fabrication by | Dorman Long (1963) |
| Opened | First bridge: 29 July 1963 Second bridge: 23 December 1996 |
| Statistics | |
| Daily traffic |  167,565 (2018)Count point |
| Location | |
 Interactive map of Thelwall Viaduct | |
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TheThelwall Viaduct (grid referenceSJ664883) is asteel compositegirderviaduct inLymm,Warrington,England. It carries theM6 motorway across theManchester Ship Canal and theRiver Mersey. It is betweenjunctions 20 and 21 of the M6, the former also being junction 9 of theM56.
It comprises two separate bridges, one of 4,414 feet (1,345 m) long carrying the northbound carriageway, the longest motorway bridge in England when it was opened in July 1963, and one 4,500 feet (1,400 m) long carrying the southbound carriageway, opened in 1995.[1] The longest single span is that of 336 feet (102 m) crossing the Ship Canal.[1]
The scheme was announced on Thursday 9 July 1959 by Minister of TransportHarold Watkinson, with theGathurst Viaduct andCreswell Viaduct, near Stafford, over theRiver Sow. The bridge would cost £5,056,678, and was to be built byLeonard Fairclough & Son, and designed by SirJames Drake.[2]
Work started in September 1959, and was to be finished by March 1962.[3] 10,500 tons of steel superstructure was made byDorman Long.[4] Concrete was supplied by Four Square Industries ofMiddlewich.[5] On Thursday 16 May 1963, the last two girders were put into place.[6] The bridge had taken longer to build than expected, and the motorway was due to open on Monday 29 July 1963. The bridge was designed to take up to 79,000 vehicles per day.
In August 1990 it was proposed to build a second viaduct, to start in 1992.[7] The £52.5m contract was awarded toTarmac Construction of Wolverhampton in October 1992, with consulting engineersPell Frischmann. Junctions 20 and 21a would be remodelled.[8] Concrete came from Pochin Group of Middlewich.[9]
In July 2002 a failedroller bearing was discovered and it became necessary to close all but one northbound lane. As the M6 at the time carried an estimated 150,000–160,000 vehicles per day, this led to serious congestion.[10] The viaduct was not completely reopened to daytime traffic until February 2005, and subsequently remained partially closed at night for further remedial work to take place.[11] In all, 148 bearings were replaced, the repair scheme costing around £52 million.[12]
The bridge's height and openness to the elements mean that it has frequently been the subject of speed reductions because of strong gusts of wind that badly affect the stability of high-sided vehicles. On several occasions lane closures have resulted as a consequence of articulated vehicles simply being blown over. However, the open sides of the bridge are a deliberate design feature to reduce the likelihood of snow drifts building on the carriageways.
At approximately 8am on 13 September 1971 thick fog led to a catastrophic multiple vehicle crash on the viaduct. More than 200 cars, trucks and tankers piled up, five vehicles burst into flames, 10 people were killed and 70 injured. It was the worst crash ever recorded on British roads at that time.[13]
In April 2011 a massivefree party took place under the viaduct, with reportedly over 5,000 ravers in attendance.[14]
On 30 September 2024, a lorry fell from the viaduct and landed on the embankment below. The driver survived.[15]
