05 February 2015

Swing Bridges on the Weaver

Time to get in the swing of things! Not that you’re allowed on a swing bridge while it’s swinging but these are yet another aspect of the Cheshire landscape that intrigue me. Apart from the old Kopu Bridge, near Thames in New Zealand – which I never realised until very recently is a swing bridge – I’d never seen bridges that moved in this way before.

As the name suggests, a swing bridge is a movable bridge that swings horizontally to one side of the waterway it spans in order to allow tall river traffic to pass. If the span of the bridge is quite short, as is often the case when it spans one of the local canals, then the bridge pivots only at one end, opening like a gate. If the waterway is wide and the span therefore longer, the bridge pivots on a central point, requiring a structure in the centre of the waterway to support it. Wikipedia has an animated clip showing this movement.  

A swing bridge can carry road, rail or pedestrian traffic across the waterway and, obviously, the traffic has to be stopped (usually by barriers and traffic signals) while the bridge is swinging. So far, I’ve only seen one in action but it was compelling viewing and I was able to get a sequence of photos of the bridge rotating the full 90 degrees and back again.

As it’s one of my nearest waterways, most of the swing bridges I’ve seen have spanned the River Weaver or the Weaver Navigation (the areas of the river that have been made navigable, perhaps through the addition of man-made channels or locks). Here are six of those bridges, in order from the most southerly (the furthest upstream) to the most northerly (the furthest downstream). The red dots on the map mark their approximate positions.

Riversdale Bridge, Northwich
The first of the swing bridge examples I will include here is also the smallest. It’s a pedestrian swing bridge across the Weaver Navigation near Hunt’s Lock in the town of Northwich. The original bridge was a wooden construction, built in 1888 and operated manually – imagine having to move that beast to one side of the river! That first bridge was replaced, around 1930, by another that was almost carbon copy of the original, but that second bridge also fell into disrepair and was closed in 2004 after it failed safety inspections.

The current swing bridge is a modern replacement, opened in December 2010, at a cost of £1.4 million. According to the Northwich Guardian, ‘All the components for the bridge had to be transported down the River Weaver on pontoons’, which, when you consider that the bridge is 45 metres long, is supported by 10 steel tie roads and weighs 50 tonnes, was no mean feat. This bridge is well used, as a short-cut from one side of town to the other, for easy school access by local children and by visitors to nearby Hunt’s Locks, so that replacement cost and the ongoing costs of the bridge's upkeep are well justified.

Hayhurst Bridge, Northwich
Not far downstream from Riversdale is Hayhurst Bridge, a substantial steel and wood construction that carries the busy B5337 (and pedestrians) across the Weaver. According to River Weaver Navigation Society historian Colin Edmondson, Hayhurst was originally known as Navigation Bridge and was built, in 1898, to allow a continual flow of traffic across the river while the adjacent Town Bridge was being converted from a fixed girder bridge to a swing bridge.

A Grade II-listed structure, this is believed to be the first bridge in Britain designed to be electrically operated, although Edmondson notes that the electricity was not connected until May 1899 meaning nearby Town Bridge may have been the first bridge to actually operate by means of electricity – an interesting distinction.

For those partial to more technical information, the Movable Bridges website reports that Hayhurst was the first bridge on mainland Britain to have a large proportion of its weight – 255 of its total 305 tones – supported on a sectional pontoon immersed in the river. Hayhurst was out of action for 9 months in 2004 for £33.5 million refit meaning it will continue to swing for a few years yet!

Town Bridge, Northwich
Six hundred metres downstream from Hayhurst and slap bang in the centre of Northwich is the aptly named Town Bridge. Built by the Weaver Navigation Trustees in 1898-99, the bridge is – together with Hayhurst – purported to be one of the first road swing bridges to be built in Britain and it was the first to be powered by electricity. The single steel span of the bridge was constructed so as to pivot from the western bank of the Weaver and, just like its neighbour downriver, this bridge is massive. Constructed of steel and wood, its superstructure weighs in at 300 tonnes and its substructure weighs 200 tonnes.

Both Hayhurst and Town Bridges have steel gates at either end to stop traffic when the bridges are in operation, and both have small timber-framed and weather-boarded control cabins situated adjacent to the bridges on the Weaver’s western bank.

Almost closed
Winnington Swing Bridge, Northwich
Just a short sail downstream from central Northwich sits another busy, road-traffic swing bridge, the Winnington Bridge. Constructed in 1908-09, it actually replaced an earlier version which had been built in 1901 but which had proven inadequate in design and in carrying capacity. It appears there was much discussion about the siting of this replacement, as there was initially a possibility that it would carry a light railway connection between Warrington and Northwich, as well as road and pedestrian traffic.

The rail option didn’t materialise so the shortest span option was chosen. The Movable Bridges website lists Winnington’s vital statistics as follows: a span of 154 feet, with a pivot point set 61 feet from the short end, giving a long arm of 93 feet; a clear waterway of 55 feet when the bridge is fully open; and it carries a roadway that is 19 feet wide and a 5-foot-wide footpath. 

Winnington Swing Bridge, wide open
According to the British Listed Buildings register, this bridge enabled significant ‘trade expansion and business growth in the area's chemical industry’. It is the only main-road swing bridge on the Weaver Navigation that is not supported on a pontoon, and it is the only one of these six swing bridges that I’ve actually seen in operation. Believe me, it’s an impressive sight to see this massive structure swing to one side and back again.

Looking upstream, showing the brick control tower at left and the island on which the bridge sits
Acton Bridge Swing Bridge
Less than five miles downstream from Winnington is the Acton Bridge Swing Bridge. Built of steel between 1931 and 1933, this bridge sits on an island in the centre of the River Weaver. It replaced an earlier bridge that was located a couple of hundred yards upstream – you can still see the original abutments on the river banks near the Leigh Arms car park.

Looking downstream, showing the circular structure on which the bridge pivots
The immensely talented man responsible for this, and the other five swing bridges listed here, was John Arthur Saner, chief engineer for the Weaver Navigation Trust from 1888 to 1934. He would, no doubt, be amazed to learn that the bridge operation for this particular bridge is now computer controlled!

Sutton Weaver Swing Bridge
The last in my series of River Weaver swing bridges is also the last before the river’s confluence with the Manchester Ship Canal near Runcorn. Built in 1872, the first bridge on this site was 75 feet long and 14 feet wide, weighed in at 20 tons and could be manually operated by just one man. By 1923, it could no longer cope with contemporary traffic so a replacement was built. The new bridge is more than twice the size of the original – it measures 150 feet long by 44 feet wide, carries three lanes of road traffic as well as two footpaths, and the combined weight of the swinging section and the pontoons it sits on is 519 tons (statistics courtesy of the Movable Bridges website).

During 2013-14, this bridge underwent a complete restoration, at a cost of £4.5million, which should ensure it continues to function effectively for another 50 years. As the bridge carries the very busy A56 and an estimated 20,000 vehicles per day, I think it was well worth the money! 

I have gleaned much of the technical information about these bridges from the most excellent Movable Bridge UK website (and contributed a few photographs to their website in return). If you’re interested in bridges in your neck of the woods, you can check their website for UK bridges, and Wikipedia has a list of some that can be found worldwide. 

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