Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Dartford's double-decker of a dream

Cover story - Thrutube, a double-decked tubular structure by Robert Eyles, is the winner of thebrief. net competition to design a second Dartford crossing. Antony Oliver reports.

Architect Robert Eyles' bold design for a dramatically tubular and partly-inhabited structure across the River Thames at Dartford turned the judges' heads with its innovative edge and the clarity of presentation.

His bridge uses what Eyles describes as a 'large spanning tubular structure' with a 'dynamic prism' section to make the 1km crossing and also incorporates energy-capturing technologies to harness power from the sun, wind and tide.

The competition judges, engineering guru Chris Wise and award-winning bridge architect Keith Brownlie, said that Eyles' design stood out for its clarity and confidence.

'I like the form of it, ' said Wise. 'It's something of a latter-day version of Robert Stevenson's Britannia Bridge over the Menai Strait. He has deliberately bypassed the manufacturing process and come up with something with real spirit and grace.' He said Eyles' distinctive sketching technique successfully described the bridge without using excessive detail.

'The fact that he has largely ignored the way that the structure meets the ground is actually helpful, ' he said.

Brownlie agreed: 'He has conveyed enough of the idea and there's nothing to correct, only stuff to develop. His sketch makes you believe that this really will work as a structure.' The challenge was to design a new structure to sit alongside the existing Queen Elizabeth II bridge over the River Thames between West Thurrock and Dartford to the east of London.

The judges were looking for 'a contemporary structure', a technological tour de force that speaks for its generation and complements the existing highlevel cable stayed crossing.

The judges awarded runnersup prizes to Thomas Critchley for his through tube design and to a team of three designers of A Hull of a Bridge (see boxes on pages 28-29).

The brief dictated that the bridge needed four motorway standard trafc lanes while maintaining 57.5m navigation clearance. Beyond this entrants were free to design at will.

A wide range of ideas was presented by the 64 entrants - some good, some intriguing and, said the judges, 'some fundamentally awed in terms of their structural performance'.

'The competition has created a fantastic community and provides an excellent medium for the exchange of ideas and comments, ' said Brownlie, referring to the huge amount of peer review comment that attached itself to entries on the competition website.

This website and competition was created by specialist drainage supplier ACO Technologies in a bid to promote engineering design excellence.

Marketing development director Peter Ridgway said: 'Engineers are not often pictured as the creative force behind innovative structural design, but this competition has shown the depth of inspired thinking that really does exist.' Brownlie said that while he would have liked to have seen more designs that really excited him, he felt that nevertheless overall there'd been a good crop of new ideas submitted by the competition entrants.

'There were an awful lot of designs that had an interesting seed of an idea but unfortunately many simply lacked sufcient information to actually justify that idea, ' he added.

Other entries revealed a lack of knowledge of how and when to stop at a good idea.

'We certainly saw some structural gymnastics for the sake of it. The sort of structural design naivety that doesn't make the structural engineering job any easier or the architecture any more beautiful.' Wise agreed: 'Fundamentally a bridge is a one line drawing.

But the line has to be sublime and the winning entries were the ones that gave us enough information to make a value judgement about the design.' There was an unfortunate tendency for entrants to make their designs too complicated and defy the laws of gravity or span further than was necessary, he added.

'Many did get the structural proportions about right, but there were many others that did not, ' he admitted.

'We saw designs that were great but not on this planet - and they would still have remained ugly anyway.' Eyles, an architect at Atkins' engineering design department, won a Sony laptop worth more than £1,000. Runners up Thomas Critchley and the team of three designers each won £100.

Winner Robert Eyles, Atkins design solutions Chris Wise: 'I like the form, it's something of a latter-day version of Stevenson's Menai Bridge.

Robert has deliberately ignored the manufacturing process and come up with something with real spirit and grace. His sketching style is great. If I had got just one sketch like this in all the years that I taught design at Imperial College I would have been delighted.

It wasn't necessary to dress this design up with all the environmental gimmickry, but it does show that he's read the brief. I also like the fact that the bridge is slightly occupied.' Keith Brownlie: 'This shows a lot of condence. Certainly you have to know that you can solve the details - that's the difference between an engineering sketch and an artistic sketch - and this indicates that he does understand what has to happen.'

Judges Keith Brownlie, director, Wilkinson Eyre Architects Chris Wise, director, Expedition Engineering

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.