Frowning at the Dubai Smile

Another quick interruption to the ongoing Swiss bridge reports - I just couldn't let this one pass!

It's another "iconic" bridge. And in Dubai, home to the world's greatest Competitive Extravagance Championships. Care to guess whether it's a structurally sound idea or not?

I have to admit, I'm always in two minds about some of the crazier bridge schemes which seem to be in vogue at present. On one hand, everything in my sober engineer's analytical heart yearns for designs which, like the Swiss masterpieces I'm currently covering, achieve aesthetic excellence by exploring an imaginative engineering concept with integrity and courage. On the other hand, I understand intellectually that in the age of post-modernist excess, there are other yardsticks by which a structure can be judged, particularly if (as in this case) it's just an excuse to erect a giant logo-as-sculpture, Sheikh Maktoum's equivalent of the McDonalds golden arches.

So, the Dubai smile. Dubai has just announced its chosen design for a seventh crossing of the Dubai Creek, following competitive proposals submitted by a variety of "specialised global companies" (none of whom are named - not even the winner - so if anyone knows who they are, please share). The new bridge crosses a 400m wide waterway, and according to one story it replaces the existing Floating Bridge, quadrupling the current traffic capacity. I hope that story has it wrong, because the Floating Bridge was only built last year!

The bridge deck is suspended from a 100m tall inverted arch (see illustration, although there's a better image here), apparently for the sole reason of creating a welcoming smile for visitors to admire. It certainly doesn't make any structural sense, as the enormous back cantilevers have to carry the weight of 12 traffic lanes in unassisted bending. Essentially, the bridge is a bit like a conventional suspension bridge (the easier way to achieve a smiling appearance) except with the support towers in completely the wrong place.

It has more in common with cable-stayed bridges with the backstay missing (e.g. Alamillo Bridge or the unbuilt River Wear Bridge), except it seems to have been consciously arranged to be even more structurally inefficient. What's especially disappointing is that it could have been made much more efficient fairly easily by stringing a few more cables horizontally between the twin cantilevers.

At 61m wide and (at a guess) about 500m long, the bridge is intended to cost 810 million dirams, which is about £147m. That works out at £4,800 per square metre of deck, which is not inappropriate for a "normal" landmark bridge but is well below the going rate for a structurally inefficient design. I don't know whether the availability of a large pool of poorly treated immigrant labour from India and Pakistan helps get the costs down or not.

Returning to my dilemma, I think it's fairly easy to take a view on this one. I can't find anything to smile about in the Dubai Smile. There's no structural rationale whatsoever, and it will be monumentally difficult to build as a result. It may be a topsy-turvy arch to fit into Dubai's topsy-turvy Alice-in-wonderland world, but essentially it's just plain old kitsch. I can see the puritan faction amongst bridge designers starting a Campaign for Real Bridges right here.

Calatrava "the McDonalds of bridges"

I thought this was an interesting little quote from an article on the opening of Santiago Calatrava's new light rail bridge in Jerusalem:

The Calatrava bridges around the world are brilliant in their design, engineering and marketing - and have earned their popularity. About 40 of them have been built so far all over the globe, so in a certain way they are the McDonalds of bridges. They all have the same processed and globalized esthetic, easy to digest but whose nutritional value is suspect.

Calatrava bridges are in their own way the Maccabi Tel Aviv basketball team of their branch. They trample all the competition, and wherever they spread their wings, there is no room underneath for other worthy bridges to sprout.

Calatrava is an unusual figure - he sits out and to one side of the bridge design profession to a great extent, while also being its contemporary exemplar. As far as I understand it, his firm now generally only produces the conceptual design of his structures, with the detail generally left to others to develop (see for example a PDF article on the Sundial Bridge). In this respect, they're more like architects than engineers, and it's possible to think of them as a franchise operation, passing out licenses in different communities to create and run their own piece of the Calatrava brand. He rarely, if ever, gets involved in engineering research, or publishing papers about his designs, unlike most of the great bridge engineers (e.g. Jörg Schlaich or Fritz Leonhardt). Calatrava gives the impression of being completely uninterested in the bridge design world outside his own office.

At the same time, his bridges are seen by many laypeople as the archetypal contemporary bridge design. Amongst professionals, it's easy to recognise a Calatrava design, as well as the numerous tribute structures. So predominant has been the post-Calatravan trend towards cable-supported gymnastics, that there is now often a very clear reaction against it (see for example RIBA's Bootle competition winner and New Islington competition runner-up).

Like McDonalds, Calatrava bridges may seem ubiquitous (especially so because of the number of similar tribute structures), and their consistent visual styling - tall; a cat's-cradle of cables; and puritan white in colour - creates a very effective brand image that promoters often want to buy into. In this respect, his bridges are more of an upmarket brand and in no way like McDonalds - think more of an expensive fashion label, perhaps.

Calatrava's bridges are also sufficiently neutral in all ways to achieve global success. They pay little attention to context or history; it's hard to imagine Calatrava designing a bridge that pays tribute to local heritage, for example.

For other bridge designers Calatrava poses a question: do you want the fame that comes from establishing a brand identity; or are you happy to be known only amongst your colleagues but retain integrity by respecting each site individually? It has to be said that most modern bridge masterpieces are by designers who follow the latter approach (e.g. Jürg Conzett). But I'm far from sure that makes Calatrava's method a bad thing. Whatever their merits in terms of cost (always too expensive) and their clear tendency to repeat and tweak a common theme, many of his bridges are hugely popular, and undoubtedly successful as sculptures. Is that enough, sometimes?