12 December 2012

"Kurilpa Bridge" by H Beck & J Cooper: Part 2

This is the second post in a multi-part review. See Part 1 for an overview of this book.

The book has four main chapters. The first of these offers a discussion of the context of the bridge, how it was designed and built, and what it signifies about Brisbane as a place. The chapter opens with another quote from my blog post, this time unattributed, and this issue persists throughout the book - very little is referenced and it's therefore often impossible to decide how much credence to give to various strands of the narrative.

I haven't seen any of the other entries to the original Tank Street Bridge design competition from which Kurilpa Bridge emerged, but the genesis of Kurilpa's unique form is well-explained. Alternative options like a suspension, cable-stayed or arched span were rejected by the design team, until a tensegrity structure was put forward, initially as a question rather than necessarily a serious proposition. The two design aims driving the team were the need for as slender a deck as possible, to minimise ramp length at the bridge's southern end, and the desire to support a canopy of some sort, to provide shade from Brisbane's intense sun. Taken together, these make the tensegrity option more rational than it may otherwise appear.

However, it's also noted that the team rejected other options because of their lack of "wow! factor" or "originality". Beck and Cooper fail to comment on the very different heuristics at work here. The desire for something iconic was driven by the ultimate client, and "originality" plays a part in satisfying that desire - no municipality, paying the kinds of money involved here, wants something that their competitor cities already have.

Deyan Sudjic's Edifice Complex is at work: a giant pissing contest played out through the medium of architecture. Engineers respond to this sort of thing by asking: is the search for novelty enough to justify the monsters that may result, bridges which may be the equivalent of the genetically engineered luminous fish? It's only where this motivation is particularly strong that initially "crazy" ideas like a 128m span tensegrity bridge have any chance of being taken seriously. Even the authors can see some element of self-conscious absurdity to the structural form, referring to "the structural histrionics of the bridge", for example.

The authors extol the bridge's "signature spiky cloud" as being "exuberant and expressive". It "transcends the utilitarian, to celebrate both the act of crossing the river and the city it ties together". Of course, any landmark bridge would probably do the same. The question, which here as in most architectural criticism is left unasked, is whether this design in particular is better than any imaginable alternatives.

I am happy enough to throw off my habitual engineering biases and recognise that the pursuit of the most efficient engineering solution does not always result in a solution which satisfies wider criteria. The value that an iconic bridge provides to a community and economy has no clear relation to the quantity of steelwork and concrete employed in its construction. Instead, a unique and instantly recognisable silhouette can be an immensely valuable thing for a city, a readymade logo writ large on the landscape. Brisbane only needed to look south towards Sydney and its Opera House, another structure with a flagrant disregard for the principles of structural efficiency.

In short, I support the book's main argument, that there must be more to life than the "Functionalist Modernism" that serves both as an engineer's aesthetic and ethic.

To be continued ...

(Images of Kurilpa bridge under construction courtesy of Margaret Donald).

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