02 January 2015

"Trutg dil Flem: Seven Bridges by Jürg Conzett" by Wilfried Dechau

There can be few contemporary bridge engineers who have been as well-celebrated in photographic coffee table tomes as the Swiss designer Jürg Conzett. Indeed, the only competitor in this arena is Santiago Calatrava, who is as inappropriate a comparator as could be found.

I think Trutg dil Flem: Seven Bridges by Jürg Conzett (Scheidegger and Spiess, 2014, 192pp) [amazon.co.uk] is the third book by photographer Wilfried Dechau to depict Conzett's bridges and the landscape in which they are set. I've previously reviewed Traversinersteg and Dorfbrücke Vals, both of which are excellent.

The Trutg dil Flem is a riverside pathway, along the River Flem north of Flims in south-eastern Switzerland. The pathway is a recent project, connecting up isolated and barely-walkable sections of path. This is only possible thanks to the construction of seven new pedestrian bridges, all designed by Jürg Conzett.

These are not especially spectacular structures, ranging in length from two to eighteen metres. They are only for use by visitors on foot, with the narrowest bridge being a mere 0.7m in width. Nor do they all exhibit the innovation for which Conzett is best known. Most are simple timber beam bridges, highly economic and suitable for the context, and in no way of particular architectural or engineering interest. They enable visitors to cross the stream, and also provide vantage points from which the surroundings can be better seen.

There are three bridges of greater interest. One is a tiny oval slab, with a bare handrail on one side only, originally conceived as a stone slab but built in concrete. It's so short as to barely be a bridge at all.

A second is a simple reinforced concrete beam, spanning 3.8m. The balustrades have cranked posts, projecting horizontally from the sides of the beam, then cranking vertically. This makes the concrete appear little more than a plank, and it looks great. It's also interesting how the balustrades continue off the bridge onto the approach staircases, which rise up the side slopes away from the bridge.

The third bridge is a very slender stone arch, almost a mirror image of Conzett's famous Punt da Suransuns. This was originally proposed as an 11m span, and drawn up as an arch of varying depth, thicker at the ends. The version eventually built spans 18m, and is equally slender over its entire length. This is made possible by using the lower rail of the stainless steel balustrade as a prestressing ribbon, pre-compressing the arch and enhancing its resistance to buckling failure. It's a marvellously ingenious solution, tremendously clever engineering in the service of minimalist beauty.

The book features a number of useful, if short, essays, in both German and English, including one by Conzett on the design of the arch bridge. His beautiful original drawings for each bridge are also included.

The bulk of the volume is taken up by Dechau's photographs, in two sections. The first documents the Trutg dil Flem and the completed bridges, giving priority to the landscape itself. It would clearly be a very attractive place to visit, and it's also clear that the bridges enhance the landscape, and are appropriate rather than showy.

The second section documents the construction of the bridges, and focuses as much on the builders as what was built. I found these a real pleasure to examine.

As with previous Dechau / Conzett books, Trutg dil Flem has been produced to a very high standard, it's a gorgeous book which well befits its subject.

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