01 April 2010

Critic critiqued

Regular readers will know that the design of a new landmark bridge across the River Wear in Sunderland has a been a topic I've returned to on many occasions. Generally, I've been pretty critical of the entire enterprise, which involves hanging a 336m long bridge deck off two giant prestressed tusks.

The designer, Techniker, has mentioned me in passing as part of a lecture to graduates in Newcastle, available on their own blog. Amongst lots of interesting material on the evolution of their design, they have this to say:

"I have really enjoyed following the blog of the Happy Pontist, a self-appointed critic of bridge design. He is a bit sad but the point is he is genuinely aggrieved. He is not the only one to use their technical authority to say this couldn’t be built then when the figures were out move to the position of it shouldn’t be built then when the cost-benefits come back set up a rear-guard action that it’s just plain ugly. For structures that are permanent, that will effectively be there for all to see forever, across all booms and recessions what is the proper thing to build?"
I'm happy to be "self-appointed", and indeed would hope that no formal license is required simply to go online and post the same views I'd happily share with people in person. I'd also note that I've never called the bridge "ugly" (I have, indeed, called it "amazingly beautiful"), nor suggested it is unbuildable.

But set these aside, because the substantive point at issue here is the final sentence, and the question "what is the proper thing to build?"

The Techniker design is structurally, and hence economically, extravagant, in the service of an essentially architectural vision. Pylons without back-stays (or with "virtual backstays", as Techniker would describe it) do not follow from any purely structural response to the logic of the bridging problem. Here's what Techniker's Matthew Wells had to say on structurally extravagant design back in March 2006 [sorry, that link may only be available to NCE subscribers]:
"'Following the Calatrava route isn't necessarily the best option. Iconic structures don't have to be overweight or over engineered. I believe there is a moral duty not to waste money on infrastructure projects. Efficient structures that give value for money don't have to be dull."
He also identified the demand for such structures to act as beacons for investment in economic regeneration. Discussing the Gateshead Millennium Bridge, Wells went on: "The contribution it's made to the image of the area and the inward investment it's attracted are priceless. That's what clients are looking for, the so-called Bilbao effect - the same impact as the Guggenheim museum had there."

So on the one hand there may be a "moral duty" not to follow (let alone out-do) Calatrava-style flamboyance, and instead to promote efficiency and value for money. On the other, there's the desire to create spectacular icons signposting urban revitalisation. The tension between the two is at the heart of any disagreement on whether, in engineering terms, the River Wear bridge is a "good" design, and at the heart of many a discussion on "iconic" bridges.

The conventional engineering point of view is straightforward, and was aptly summarised by Woodruff and Billington in their review of Calatrava's costly Sundial Bridge: "the drive for landmark bridges has led some engineers to disregard the engineering ethic of economy with some recent footbridges". I've covered this sort of philosophy before, as it has been espoused by most bridge engineers writing on aesthetics: Menn, Leonhardt, Virlogeux and others. As I noted when discussing Woodruff and Billington, value should be more than just a monetary concern, and hence an obsession with economy unfortunately tends to reduce value to a matter of bean-counting. While engineers instinctively like anything that is measurable, there is more to life than a conventional cost-benefit analysis can capture. What price joie de vivre?

Clearly, the River Wear design could be considered visionary, innovative, monumental, even inspiring in its ambition. It puts the "icon" in "iconoclastic". It will have a value both for the spirit of the neighbourhood and for whatever investment in regeneration it can trigger. The question for me is not whether it meets these goals, but whether a different design could also have met them, and whether such a design could be more structurally efficient, and hence offer the taxpayers a better balance between value and cost overall.

I don't see how else you can balance the scales of cost and value other than by comparing a number of alternative options, and I find it hard to believe that in this instance, a more efficient design wouldn't have delivered substantial value for significantly less cost. I think my difficulty with the Wear design also comes down to a bridge engineer's basic instinct: there are other "iconic" bridges which are notable for their extravagance (e.g. the Gateshead Millennium Bridge, one of the most expensive footbridges ever built, for its size), but which have a more conventional structural logic.

Perhaps only posterity will tell whether the Sunderland bridge is destined to be regarded as an engineering marvel along the lines of Eiffel's tower (much criticised when it was first proposed), or simply the bridge world's equivalent of an architectural folly.


Anonymous said...

Gateshead Millenium Bridge seems much better value for money than the facile £19m Anish Kapor sculpture for the London Olympics - at least it has a function!

The Happy Pontist said...

I've always admired Anish Kapoor's art, but the pictures I've seen of his Orbit proposal do make it look remarkably ugly. I believe the function is to hold up a viewing platform and restaurant? Or was I just tricked by a day-early April Fool?

Anonymous said...

If £19m can be justified to build a structure to hold a platform and a restaurant then I believe the New Wear bridge can easily justify its value for the purpose it is to be built.

And even if it doesn't maybe the solution is to add a restaurant at the top? Surely at that height it will be even better than the Anish Kapor sculpture???

Get the bridge built. Our society needs innovation to escape from the everyday routine that our world has come to.

The Happy Pontist said...

There's some good comment on the Kapoor folly in the Guardian today.

Anonymous said...

I think its important to note that the people for whom this bridge is being built, voted to pay and build for it. Last I heard 95% of Sunderland chose to build this design, rather then spend the money elsewhere developing the city... It goes to show just how significant a noise these 'tusks' might have for Sunderland.
In terms of the engineering, the evolution of the structural logic needs to be published in order for those interested to actually get a sense for how it works.

Margaret Powell - happy out at sea... said...

A photo and brief article in the Guardian Weekly of 7May2010 alerted me to this fabulous project. I do hope that the Sunderlandians will get this bridge. To me it looks like a true symbol of hope, a ribbon whose bottom arc is submerged in the water. Did the architect/engineers take some inspiration from Calatrava, I wonder? On that subject, you can say what you will, but Calatrava's structures, be they bridges, or train stations, airports or bus shelters, do their jobs beautifully and seem to be pretty low maintenance, too. Surely, that is a consideration when it comes to "counting the beans"?

The Happy Pontist said...

To respond to "anonymous", it's simply not true that 95% of Sunderland supported the River Wear design. 93% of a survey of a mere 161 people thought the design was "good or very good". But 49% of a larger survey (1,641 responses) would have preferred a "tried and tested" design, and 58% wanted to minimise the impact on Sunderland taxpayers - which the chosen design certainly doesn't.

When anonymous suggests that "the evolution of the structural logic needs to be published in order for those interested to actually get a sense for how it works", this is simply nonsense. It's obvious how it works, and the Techniker lectured linked to from this post makes clear the structural philosophy - two giant post-tensioned cantilevers from which the bridge deck is suspended, a form of design never attempted anywhere else because, I believe, most clients and engineers would react instinctively against the lack of economy and the lack of an engineering rationale for doing so. The rationale for the bridge's design is entirely visual i.e. it's a post-modern bridge, whereas most bridge designers still adhere to the tenets of modernism.

Responding to Margaret's comment, I doubt they took any inspiration from Calatrava, although the bridge does resemble an old Scottish National Party logo. There are only a couple of Calatrava designs where the mast isn't inclined away from the deck, and these are on a much smaller scale. Calatrava is much derided by bridge engineers for the lack of structural logic to his designs, but he has never attempted anything as outrageous as the Sunderland bridge. As for Calatrava's bridges being low-maintenance, there are several reports of maintaining authorities unhappy with the difficulty of looking after his works (Salford, Venice, Bilbao etc).

The question is this, if Sunderlanders really want a gigantic monument (or folly, in the traditional architectural sense) to shout "look at us", why not build precisely that, as was done with the Angel of the North?

Anonymous said...

There will always be a difference between the Eiffel Tower and the Techniker design: the elegance of the Eiffel Tower might be questioned, but its shape is optimal to withstand wind load. Therefore, it is a marvel from the point of view of structural engineering and it makes completely structural sense...I do not think that this is the case for the Techniker design. To me it is a design that symbolizes the era before the latest crisis where appearance was the most important thing. And in bridges, as it happens also with persons, appearance is not an absolute value and, of course, the absolute value.

Anonymous said...

This bridge will never be built.