"Kurilpa Bridge" by H Beck & J Cooper: Part 1

Way back in July, I posted here my surprise and delight at seeing this blog cited prominently in the preface to Haig Beck and Jackie Cooper's book, Kurilpa Bridge (Images Publishing, 2012, 100pp) [amazon.co.uk].

I think this may be the only book in print to use The Happy Pontist as a key point of reference. The book is in part a fairly conventional piece of architectural criticism: a discussion of the titular bridge, its merits, and its place in a wider context of bridge-building. More interestingly, it's an attempt to understand how the bridge can appear as "controversial" to engineers, how it ignores the ideas of aesthetics common in the bridge engineering community, how those ideas came to be and remain in place.

The point of departure for this is a post I wrote in 2009, part of a series of posts on "tensegrity bridges". As I noted at the time (and the authors of this book acknowledge), Brisbane's $63m Kurilpa Bridge is sometimes described as a tensegrity bridge, but isn't really such a beast. As coined by Buckminster Fuller, the term refers to a structure where the compression elements are "islands" in a sea of tension, i.e. struts are connected to ties, but never to other struts. Completed in 2009, Kurilpa is a cable-stayed bridge, albeit an exceptionally complex one. The deck is sheltered under an awning, which is supported by pure tensegrity elements over part of its length.

In my post, I suggested that Kurilpa Bridge is:

"irrational, visually chaotic, disruptive, and possibly one of the most expensive fixed footbridges ever built"

The authors see this as a complaint, and one common to engineers, who see order and simplicity as both economically attractive as well as defining an aesthetic good.

They also take issue with my judgement on its expense (indeed, my original post did get some of the figures for the bridge wrong), although I'd note that any evaluation of the bridge's cost is skewed by the length of its approach ramps, which are clearly of much cheaper construction than the main river spans. Brian Duguid's moderately-definitive 2011 study of landmark footbridge costs puts Kurilpa as equivalent to €77k per metre span, which is about twice the median for landmark pedestrian bridges. So, maybe not one of the most expensive footbridges, but clearly a Porsche rather than a Nissan.

Beck and Cooper also draw attention to this quote from my post:

"Like many bridge engineers, I like a bridge where the structural principles are clear and comprehensible"

They see this as a heuristic, a rule-of-thumb which can be used to form value judgements. Their book sets out to explore this clear expression of engineering values, to demonstrate that it is a specific cultural artefact rather than (as engineers often think) an absolute, and hence to attack the idea that Kurilpa Bridge's higgledy-piggledy appearance is in any way a bad thing.

I think it's only fair to point out that my views on the merits of Kurilpa are not as straightforward as these quotes suggest. In the same post, I also said:

"I do admire its audacity, the willingness to install something that works against the orthogonality of its surroundings, a provocation which offers restlessness in place of reassurance"

and:

"it's undeniably a landmark, an innovation and a substantial technical accomplishment"

Indeed, I have in the past taken the same side as Beck and Cooper, critiquing the tendency of many engineers to treat their modernist aesthetic as a matter of morality rather than simply one of several possible philosophies. The engineering community's puritan distaste for flamboyance is something I've covered extensively on this blog in the past.

Okay, I'll stop there for now. It turns out this book review is getting pretty long, so I'll split it into parts, and continue in another post.