A footbridge protecting snails… and rowers…

Posted by Derek Mason

20th June 2023

Picture credit: Harry Grout on Unsplash
Caption: Rowers on another stretch of the Thames

Creating a Thames-side footbridge that’s structurally sound, looks impressive, and fits in with its existing surroundings is no mean feat. Add to that the challenges of being high enough not to disturb rowers and low enough to allow maintenance of an existing Victorian railway bridge, and you’d expect a fairly functional bridge.

Dukes Meadow Footbridge, however, strikes a sensitive note in its Chiswick surroundings. If you’re interested in such things, I recommend finding an image online – or visiting in person – to experience the remarkable design by Moxon Architects and structural engineers COWI.

It’s the perfect answer to a problematic stretch of the Thames Path, where previously people were unable to cross the railway line close to the river. As it says in the London Borough of Hounslow’s report, Duke’s Meadow Regeneration, the bridge is responsible for “removing a frustrating dog-leg along the scenic walking and cycling route”.

Before the bridge’s construction, the path north of the Thames left the river and diverted 300 metres to the nearest tunnel under the railway embankment. Now, people can continue on their way through this “peaceful, almost rustic, part of the Thames” which Hounslow’s report says is “one of only two surviving natural Thames river banks in London”.

The architects and engineers overcame several challenges. Firstly, Barnes Railway Bridge is a Grade II listed bridge, so it could not be used as support for the footbridge. Secondly, the bridge needed to be low enough to have enough clearance under the existing bridge and not prevent bridge maintenance, but high enough not to affect rowers at high tide.

Thirdly the route and lighting for the bridge needed to consider any potential impact on endangered snails in the local nature reserve. And finally, the bridge needed to be able to arrive on the Thames itself, travelling 36 miles and passing under 21 bridges. So, there was certainly a lot for the designers to take into account.

The main bridge section was floated into place at high tide on pontoons last summer – in 2022. It was specifically designed to settle into the correct position on its footings when the tide went down.

The bridge is a half-through truss structure, with braces angled to maximise views of the river – both from the bridge, the shore, and the river itself. It was built in Tilbury, Essex, with a reduction in carbon emissions in mind. Construction of the stainless steel and aluminium structure used techniques that allowed a 50% reduction in carbon emissions usually associated with trusses, and a 30% reduction in the overall carbon footprint of the entire bridge.

Hugging the shoreline, the 115m-long footbridge has also been placed with future flooding in mind and uses energy efficient lighting. It’s a safer, more accessible route along the river, and is a shining example of a project that focuses on local people’s needs and wellbeing, rather than solely on commercial requirements. It’s a project to be proud of.

Meanwhile, my team and I are based a little further along the Thames, in Twickenham. If you find you need assistance with the structural elements of an upcoming project, please do get in touch.

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