Monday, October 17, 2016
‘The Smile’, a spectacular, curved, tubular timber structure measuring 3.5m high, 4.5m wide and 34m long, by the American Hardwood Export Council (AHEC), Alison Brooks Architects (ABA) and Arup has paved the way forward for the use of hardwood cross-laminated timber (CLT) in the construction industry. On display at the Chelsea College of Art Rootstein Hopkins Parade Ground until October 12 as part of London Design Festival 2016, the installation showcases the structural and spatial potential of CLT using American tulipwood. As one of the Festival’s Landmark Projects, which can be inhabited and explored by the public, ‘The Smile’ is effectively a beam curving up at both ends and is the first ever ‘mega-tube’ made with construction-sized panels of hardwood CLT.
‘The Smile’ is the first project in the world to use large hardwood CLT panels manufactured by Züblin Timber; in fact, the entire structure is made from just 12 huge tulipwood panels, each measuring up to 14m long and 4.5m wide. For AHEC, fabricating these panels in a real CLT production plant has been an important step forward, showcasing how the material can be used for commercial projects.
According to Andrew Lawrence, Global Timber Specialist, Arup, ‘The Smile’ is the most complex CLT structure that has ever been built. Not only does it have a double cantilever, but the entrance door is placed right at the center where the stresses are highest. In essence, it’s two 15m cantilevers; if you turned the structure vertically and added the weight of 60 visitors at one end, it’s equivalent to the core stabilizing a five-storey building. Nobody has ever built a core that slender in timber. However, compared to other woods, tulipwood is surprisingly strong for its weight. It’s significantly stronger than spruce, but still low enough in density to be easy to kiln dry, easy to machine, easy to transport and easy to screw into, making it suitable for the project.
Commenting on the emergence of timber buildings and on the role of CLT, Lawrence says: “Timber has many advantages, but I think the biggest is speed. Timber is lightweight and with computer fabrication it can now be machined to incredibly tight tolerances. This makes it ideal for prefabrication and rapid assembly. Assembling a timber building is like assembling a giant piece of flat pack furniture. The development of CLT has been a key part of the timber revolution as it gives us a way to create large timber panels which can be used for the walls and floors of entire buildings, without the need for any wet concrete trades.”
Tags: AHEC, American Tulipwood, Arup, Cross Laminated Veneer, London Design Week, The Smile
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