I reported over a year ago on the outcome of a competition for the design of a footbridge for the London 2012 Olympic Park. That was won by Adams Kara Taylor with Heneghan Peng.
Now, the first parts of their unusual bridge design have been installed on site by contractor Lagan Construction.
The design is for three permanent link bridges spanning 36m above Carpenter's Lock. What makes them unusual is that during the Olympics, the spaces between these structures are also filled in, creating a single bridge some 54m wide. Once the circus leaves town, the temporary infill structures are to be removed.
The geometry is such that the two edge bridges have a curved, twisting form. These two structures (each weighing between 40 and 50 tonnes) were erected in early March (see video). Structurally, they are tubular space trusses, sufficiently unbalanced in shape that they need to be temporarily propped until the third link bridge is installed between them (due to take place in April).
They are also clad in mirror-polished 4mm thick stainless steel, the fabrication of which will have been quite a challenge. I guess from below they will give the impression of some kind of giant Anish Kapoor sculptures (see picture). Building magazine has much more information on the difficulties of fabrication and construction.