A massive but intricate timber structure that took shape outside London’s Victoria & Albert Museum in time for the London Design Festival in September provided a visible symbol of the Museum’s commitment to the Festival as well as being a bravura example of imaginative design. But it was also much more - a demonstration of the power of collaboration, of what can be achieved when some of the best imaginative, analytical, and practical minds come together to create something that is at the limits of the possible. Called the Timber Wave, the 12.5 m high structure was designed by architect AL_A with engineer Arup and specialist fabricator Cowley Timberwork. Made using American red oak, it is the third collaboration between the American Hardwood Export Council and the London Design Festival - and the most ambitious. Despite its huge size, it uses furniture-making techniques and bent timber in a manner more common on a much smaller level. Amanda Levete, the founder of AL_A, said, “Normally I feel uncomfortable if a design doesn’t have a function at its core, but the purpose here is very clear: to create something that is self-supporting, that is made out of timber with minimal steel connectors, that goes 12.5 m high and doesn’t need to be tied back to something”. She described it as “The most structurally complex project that we have ever undertaken, which was deeply stressful but ultimately successful”. The idea, which evolved after the team rejected several earlier concepts, was to create a self-supporting arch, with one end standing on the pavement and the other on the shallow steps of the museum. It has a direct visual relationship with the intricate carved stone arch of the museum entrance. Structurally, the form is a series of trusses, but this is not visually obvious because the elements of both the chords and the braces are all curved, so that it is not easy to read structurally. And, of course, it made the structural engineering far more complex. Ed Clark, a director at Arup, said, “We worked very hard to embed structural stability. The distortion complicates the load paths”. What made it particularly complex was that, because the structure is synonymous with the appearance of the piece, any engineering changes immediately affected the architectural concept. So there had to be an iterative approach, with Arup sending changes back to AL_A, which would make adjustments, leading to Arup needing to recalculate and make further amendments. Andrew Lawrence, the timber expert at Arup, said “There was just a tiny intersection of the circles of budget, time and engineering. Every piece is different and every piece is working at 110%, yet somehow we have got there”. The design uses glued laminated timber (glulam) and one issue was that the tighter the curves, the thinner the laminations had to be. The other challenge was with the jointing. The chords were broken down
