[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-268616-105":59,"doc-detail-268616-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","the-smile-the-first-large-scale-use-of-hardwood-clt","The Smile - The first large scale use of hardwood CLT","","The Smile was constructed for the 2016 London Design Festival as a pioneering large-scale application of hardwood CLT, combining ambitious structural performance with an architectural installation in the form of a smile-shaped double cantilever. The work traces the development of structural use of American hardwoods, highlighting how tulipwood was selected through testing and how its properties enable thin, cost-relevant connections. It details geometric constraints, CLT panel configuration, and load design based on fire and Eurocode considerations.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/the-smile-the-first-large-scale-use-of-hardwood-clt/268616/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/the-smile-the-first-large-scale-use-of-hardwood-clt/268616.png","ImageObject",300,407,{"name":92,"@type":93},"Evangeline","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-11-02","2026-09-15",true,{"@type":102,"interactionType":103,"userInteractionCount":52},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What makes The Smile a landmark CLT structure?","Question",{"text":112,"@type":113},"It represents the first large scale use of hardwood CLT and is also among the most ambitious CLT structures due to the torsion-tube behavior created between panels.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Why was tulipwood chosen for the CLT panels?",{"text":117,"@type":113},"Tulipwood offers suitable hardwood strength with low density that eases drying, machining, and connections, and testing indicated nearly 3x the rolling shear strength and stiffness versus spruce.",{"name":119,"@type":110,"acceptedAnswer":120},"How were geometry and panel thickness determined for transport and performance?",{"text":121,"@type":113},"Panel width was constrained by UK transport limits (4.5 m without escort), which shaped the central wall and curved roof/floor panels; thickness then followed from tulipwood plank availability and design needs, with a minimum viable 100 mm for a 5-layer board.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},268616,1789433375,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":52,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":52,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":143,"preview_page_count":4},13056703019662,"https://ap-avatar.wpscdn.com/avatar/be000253a8e92610077?_k=1778726343310543188","The Smile: The first large scale use of hardwood CLT  \nLächelnde Skulpttur aus Tulipwood (CLT)– the Smile Sculpture souriante en tulipier de Virginie (CLT)– the Smile  \nAndrew Lawrence Arup London, UK  \nIshan Abeysekera Arup London, UK  \nEd Clark Arup London, UK  \n2  \n 22. Internationales Holzbau-Forum IHF 2016 The Smile: The first large scale use of hardwood CLT | A. Lawrence, I. Abeysekera, E. Clark  \nThe Smile: The first large scale use of hardwood CLT  \n1. Introduction  \nThe Smile, constructed for the 2016 London Design Festival represents the first large scale use of hardwood CLT. In terms of the forces between the panels, to create a torsion tube, it is also arguably the most ambitious structure ever built in CLT. This paper looks at the development of the structural use of the American hardwoods, discusses why tulipwood was chosen for The Smile and explains the structural design.  \n2. Development of structural use of the American hardwoods  \nFor the courtyard roof of Portcullis House (Figure 1, London, completed 2001), Hopkins Architects were keen to achieve very thin members and Arup suggested the use of American white oak. The timber had never been used before structurally in Europe and detailed testing at BRE showed that it could achieve D50 strengths, enabling incredibly thin members.  \nThe American hardwoods had traditionally been used for joinery, but Portcullis demonstrated the structural potential and encouraged the American Hardwood Export Council to test three further species at BRE (Structural Design in American Hardwoods, Arup, 2005)  \n– red oak, ash and tulipwood. It was this testing which enabled Arup and AL_A to design the tightly bent micro-laminated members of the Timber Wave for the 2011 London Design Festival (Figure 2) . However, of the three timbers tested, by far the most interesting was tulipwood.  \nFast growing and capable of being harvested after only 40 years, tulipwood has a similar density to softwood but the strength of hardwood. The low density makes it is easy to dry, machine and connect (such as with standard self-tapping screws); this ease of making connections was vital, since it is the connections which dominate the cost of any timber structure. There are about one billion cubic metres of standing tulipwood trees in the southeastern United States. The clear material is popular for painted joinery work, but the lower grade material with knots has little value. This abundant lower grade waste material appreared to be the perfect raw material for CLT.  \nIt was for this reason that tulipwood was chosen for the CLT panels for the Endless Stair (Figure 3, Arup and dRMM, London and Milan, 2013) . The CLT strengths were determined from the original tulipwood strength testing at BRE, combined with new rolling shear tests which were carried out at Trento University. The latter showed excitingly that the tuliwood had nearly 3x the strength and stiffness of spruce in rolling shear. However, the Endless Stair was still very much an experimental project, limited to small panels of hardwood CLT. The next step was to build a structure using full size commercial panels.  \n3. Architectural concept  \nAlison Brooks Architects were commissioned to design a tulipwood CLT structure for the 2016 London Design Festival using large CLT panels that would visibly demonstrate the strength of the hardwood. Alison Brooks‘concept was to create a double cantilever, curved into the shape of a smile. The double cantilever was to be inhabitable, to create an interactive sculpture.  \nThe CLT was to be visually exposed both inside and outside. While CLT should not be used in Service Class 3, the installation was only to be in place for 4 weeks, such that decent roof waterproofing, end grain sealant and a surface sealer on the vertical outer faces would ensure that the timber remained in Service Class 2, in spite of the London climate.  \n4  The Smile: The first large scale use of hardwood CLT | A. Lawrence, I. Abeysekera, E","cbCaigtVvIrApDq4","https://ap.wps.com/l/cbCaigtVvIrApDq4","pdf",963395,"English","# 1. Introduction\n# 2. Development of structural use of the American hardwoods\n# 3. Architectural concept\n# 4. Structural design\n## 4.1 Overall size and geometry\n## 4.2 Design load","[{\"question\":\"What makes The Smile a landmark CLT structure?\",\"answer\":\"It represents the first large scale use of hardwood CLT and is also among the most ambitious CLT structures due to the torsion-tube behavior created between panels.\"},{\"question\":\"Why was tulipwood chosen for the CLT panels?\",\"answer\":\"Tulipwood offers suitable hardwood strength with low density that eases drying, machining, and connections, and testing indicated nearly 3x the rolling shear strength and stiffness versus spruce.\"},{\"question\":\"How were geometry and panel thickness determined for transport and performance?\",\"answer\":\"Panel width was constrained by UK transport limits (4.5 m without escort), which shaped the central wall and curved roof/floor panels; thickness then followed from tulipwood plank availability and design needs, with a minimum viable 100 mm for a 5-layer board.\"}]","The Smile - The first large scale use of hardwood CLT | PDF",25]