24 May 2012

River Wear bridge: an update

It seems that the NCE's news story featuring Simon Bourne's criticism of Sunderland's River Wear crossing (see my last post) has attracted quite a lot of comment. I guess that's why the magazine went for it in the first place, the chance to generate some controversy, column inches and pageviews.

First up are the comments on the NCE's website. At the time of writing there are 12 comments, which may not seem much, but is a positive bonanza by the website's normal standards. Civil engineers are normally true to their name, civil, and reluctant to voice strong opinions in a public forum.

The comments are fairly evenly divided between those pro and ante the bridge design. On the pro side are comments like these:
"The bridge is elegant. Difficult to build -yes, but elegant. As a Bridge engineer myself, I can only envy those who will be taking on this design and build challenge."
"It looks exciting, and design is not just about cheapness. It is better to design to please many and offend some, than to design to not offend anyone."
One comment seeks to justify the "iconic" nature of the Sunderland bridge by comparison to past engineering glories:
"The world is scattered with costly design examples, not only of bridges, that are striking, memorable and, by Mr Bourne's theory, should never have been built. A few to ponder are The Eiffel Tower, Sydney Opera House, The Forth Railway Bridge, etc."
That one made me chuckle. The River Wear bridge adopts a design where the structural engineer has taken an entirely submissive attitude to their architect friend, essentially promising to make a vision work, at any cost, regardless of the Herculean structural feats required. Compare the Eiffel and Forth structures, where the engineer led the design and where the geometric form directly responds to the structural imperatives. The Sydney Opera House is, on the other hand, a better comparison: a completely unsuitable structural form, with an architect unwilling to compromise, where the work ran grossly behind programme and over budget. Today we can say this is justified by the enduring presence of an architectural masterpiece, but for the client at the time it was little short of a catastrophe.

I found another comment profoundly depressing:
"If you want, and can afford, to have an 'iconic' structure instead of a bog standard box girder bridge; Good, I'll design and supervise its construction. My brief is to make sure that it doesn't fall down or fail to meet building regulations. It is the promoter's responsibility to meet the cost!"
This is a trait I hate to see in engineers - the view that we are simply the servants of the visions of those better suited, that we should only be the "calculators", in Le Corbusier's notorious phrase. That's not a world I would wish to work in - I'm happier in one where engineers can have their own vision, contribute actively to aesthetic, commercial and political discussions.

Here are some of the comments from those opposing the design:
"I always said that if I was a client I would sue the design team of my project if it won an RIBA award on the basis that it would be over-priced, difficult to build and probably expensive to maintain."
"I'm afraid I have to categorize it as an architect's whim. It is overly complicated and does not present a clear structural statement of what it is trying to achieve."
"... it fits into the architects inflated ego category and an extreme waste of public funds."
"A wonderful monument to architects sticking two fingers up at economic construction - and the councellors all too dazzled to call for sanity. I have no objection to landmark structures and abhor utilitarian design, but surely in these days of economic constraint it is better to get an economically designed project constructed ASAP - and have change left over for the next one - rather than splash out on expensive fantasies."
As I've observed before, a distaste for extravagance is deeply ingrained in the engineering psyche. If a student over-designs the reinforcement in a beam section, they will fail their test - the working assumption throughout an engineering education is that economy is king, and the engineer's job is to minimise materials and cost. The possibility that what we design can have a value beyond the purely functional is rarely if ever acknowledged.

This week's NCE continues to explore the story. In the letters page, architect Martin Knight writes:
"Investment in infrastructure which is well designed, encourages growth, and reinforces social, environmental and economic sustainability is highly valuable."

Knight, of course, was the architect for England's other major current bridge scheme, the Mersey Gateway (pictured, click for full-size image). Like Sunderland's River Wear crossing, this is a cable-stayed bridge design, although far more conventional. The Mersey design is clearly a landmark design with a strong aesthetic vision, but founded on an assessment of what makes engineering sense, in this case towers with balanced cable-stays, and a truss deck which contributes significantly to the overall stability.

There's also a strong contrast in the two schemes' approach to procurement. The promoters of Mersey Gateway accept and encourage their bidders to depart from the original vision in the interests of saving money - the structure which will be built is unlikely to retain either the harp cable layout or the truss deck, although I imagine the single plane of cables has a fair chance of surviving. In Sunderland, the architect's vision appears to be sacrosanct, and must be built however difficult it may become.

This week's NCE also features an opinion piece, which mentions both these schemes and compares them to the eye-wateringly awful ArcelorMittal Orbit (pictured left). This resembles a giant corkscrew onto which a wino is vomiting jets of blood. It is half observation tower, half-giant sculpture, and it's that neither one-thing-nor-the-other quality which makes it such a failure. The economic case for the Orbit is simple: a very rich man is paying for it, so we don't have to, and whatever value it offers is therefore an easy win. The possibility that, carbuncle-like, it actively degrades the aesthetic value of everything around it, is surely too cynical to contemplate.

Other blogs are getting in on the act, with one making the not unreasonable point that debate over the merits of the River Wear bridge is ill-informed without a better understanding of its costs, and the costs of the alternatives, figures which are not easy to extract from publicly available information.

I'm aware that the bridge's promoter, Sunderland City Council, is pretty unimpressed with the NCE's coverage, stating that the scheme:
"has been rigorously designed, costed, admired and backed within the industry and profession, including the Institution for Civil Engineers which presented the project with a CEEQUAL award ... The project is functional and symbolic, and its regeneration benefits were recognised by the Department for Transport in its decision to award funding."
Sunderland's website for the project reproduces much of the relevant documentation. The most interesting in the context of the present debate are the reports which attempt to put a value on the choice of a bridge with striking rather than commonplace aesthetics. These calculate that the landmark bridge design offers £33m of economic benefits which wouldn't apply to a conventional girder bridge design, most of that in generation of employment.

The document is riddled with flaws, foremost of which is that it calculates the cost-benefit ratio for the chosen landmark design, but doesn't actually compare it with what a conventional alternative would achieve. Many of the figures used are highly debatable, and a series of other landmark bridge case studies are presented, but offer at best anecdotal and certainly no quantitative evidence.

Nonetheless, I'd recommend the report to anyone interested in this debate, which surely needs to move on from the rather simplistic battle between engineering puritans and starry-eyed visionaries which we're faced with at present. There undoubtedly is a case to be made that a bridge as spectacular as Sunderland's will be justified if the additional benefits it brings are sufficiently large, and this would be true irrespective of its structural efficiency, which is not an issue of much interest outside the profession concerned.

The Sunderland promoters are unafraid to make the case that cheapest is not always best, that appearance remains important even in the middle of recession, and that value-generation is the important measure of viability. Anyone arguing against that needs to show not just that the alternatives are much cheaper (as they clearly are), but that the value lost is not significant, and that the end result isn't a blot on the landscape which future generations will look at with regret.


Matthew Wells said...

Now that the tenders on the above project are in it's probably acceptable for a professional engineer to comment.

As the desigenr (with Stephen spence) of this bridge I beleive it should be considered in three contexts; architectural, engineering,commercial.

Those engineers with a proper design training will hold views on the architectural solution. The engineering has been involved and very enjoyable. My associates have demonstrated outstanding skills to realise it. Is it value for money? Perhaps best left to the client to judge where to spend his/her money. I hope the scheme reflects that vibrant, extraordinary city I've known the past 20years.

If there's now an interest in making a proper critical superstructure around engineering and applications of technology then it is timely.

Two things about this bridge:
Like all bridges it's for 120 years so questions of design in austerity need careful consideration
Technology's elegance in economy? Look in your garage. If we all drove Trabants we'd save a great deal.

Concluding: Architects who know me are unlikely to use the epithet submissive and I've rather more sympathy with sparse elegance than given credit for. However I want engineers to be self-conscious in their design not just hope convention will somehow generate the'correct'solution.

Bridge designers are a terribly defensive lot.

The Happy Pontist said...

Matthew, thank you for taking the time to comment, it is always good to hear from the designer. The engineering press in general is either lazy or rhetorical in nature, and there is far too little actual conversation.

My reaction to the Wear Crossing design is one of visceral dislike, but I am self-conscious enough to be aware this view is as much formed of habit as it is entirely rational. I've spoken to many other engineers who hold essentially the same point of view on the bridge, but whose obsessive dislike of extravagance leaves them unwilling to listen to any alternative.

I think there's a debate to be had not just about "what should be built", but about issues of what and how such things should be procured. The necessary judgement of value is too often ignored in both procurement and in politics.

I look forward to seeing the tender prices, of course.