[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-268496-105":59,"doc-detail-268496-en":131},{"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":124,"head_meta":126,"extra_data":128,"updated_unix":130},105,"en","cross-laminated-timber-properties-including-effects-of-non-glued-edges-and-additional-cracks-research-article","Cross Laminated Timber Properties Including Effects of Non-Glued Edges and Additional Cracks - Research article","","Cross laminated timber (CLT) consists of timber layers with alternating grain directions, with glue applied on faces but typically not on in-layer edges. Unbonded edges act as precracks, and differential thermal and moisture expansion after installation can generate additional cracks that alter CLT properties over a structure’s service life. Extending variational mechanics for aerospace composites, the paper derives analytical solutions for in-plane mechanical and thermal/moisture expansion properties of a three-layer CLT panel, and uses them to estimate effective properties for panels with arbitrary layer numbers.",{"@graph":69,"@context":123},[70,84,106],{"@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/cross-laminated-timber-properties-including-effects-of-non-glued-edges-and-additional-cracks-research-article/268496/",{"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/cross-laminated-timber-properties-including-effects-of-non-glued-edges-and-additional-cracks-research-article/268496.png","ImageObject",300,407,{"name":92,"@type":93},"Aurelia","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-29","2026-09-15",true,{"@type":102,"interactionType":103,"userInteractionCount":105},"InteractionCounter",{"@type":104},"ViewAction",12,{"@type":107,"mainEntity":108},"FAQPage",[109,115,119],{"name":110,"@type":111,"acceptedAnswer":112},"What causes “precracks” in cross laminated timber (CLT)?","Question",{"text":113,"@type":114},"CLT layers are bonded on their faces but usually not on edges within layers, so the exposed edges define periodic precracks in the composite.","Answer",{"name":116,"@type":111,"acceptedAnswer":117},"How do additional cracks affect CLT performance?",{"text":118,"@type":114},"Additional cracks formed by differential thermal and moisture expansion can reduce mechanical and expansion properties and change structural durability considerations over the service life.",{"name":120,"@type":111,"acceptedAnswer":121},"What analytical approach does the paper use to model CLT with cracks?",{"text":122,"@type":114},"It extends variational mechanics methods for aerospace composites to derive analytical solutions for in-plane mechanical, thermal expansion, and moisture expansion properties of a three-layer CLT panel as functions of crack density.","https://schema.org",{"og:url":83,"og:type":125,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":127,"canonical":83},"index,follow",{"doc_id":129,"site_id":62},268496,1789431697,{"code":4,"msg":5,"data":132},{"doc_id":129,"user_id":133,"nickname":92,"user_avatar":134,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":135,"file_id":136,"file_url":137,"file_type":138,"file_size":139,"view_count":105,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":140,"language":141,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":142,"faqs":143,"seo_title":144,"seo_description":67,"update_tm":130,"read_time":145,"preview_page_count":4},1099514068365,"https://ap-avatar.wpscdn.com/avatar/10000253d8d9f28188e?x-image-process=image/resize,m_fixed,w_180,h_180&k=1794309523707217728","European Journal of Wood and Wood Products  \nVolume 75, Issue 6, pp 973–983 (2017)  \nCross Laminated Timber Properties Including Effects of Non-Glued Edges and Additional Cracks  \nJohn A. Nairn  \nReceived: 19 January 2017; Published November 2017: DOI 10.1007/s00107-017-1202-y  \nAbstract Cross laminated timber (CLT) is usually comprised of multiple timber layers having alternating grain directions. Because individual boards are glued on their faces between layers, but usually not glued on their edges within layers, those edges define “precracks” in the composite. When exposed to differential thermal and moisture expansion after installation, CLT, like all cross-laminated composites, is prone to formation of “additional cracks.”Confidant CLT design must be able to account for changes in CLT properties during life of a structure caused by such additional cracks. By extending variational mechanics methods for aerospace composites, this paper provides analytical solutions for all in-plane mechanical, thermal expansion, and moisture expansion properties of a three-layer CLT panel. By using the three-layer solution to evaluate effective layer properties as a function of the number of cracks, the analysis can be extended to in-plane mechanical, out-of-plane bending, and expansion properties for CLT panels with any number or arrangement of layers. Some sample calculations are provided along with comments on limitations of the approximations and needs for future work.  \n1 Introduction  \nCross laminated timber (CLT) is usually made by laminating three or more timber layers such that grain directions in alternate layers are at right angles to each other. Glue is applied between the layers on timber faces, but, most commonly, no glue is applied on timber edges within layers. In other words, CLT is a precracked composite where timber edges represent periodic “precracks.” Furthermore, CLT will develop “additional cracks” over time due to environmental exposure and differential layer shrinkages. This fact is known from observed cracks within installed CLT (Nairn, 2016b) and is expected from experiments on cracking of layers in other cross-laminated structures (Nairnand Hu, 1994; Nairn, 2000) . Prior work also shows that added cracks form more easily as layer thickness increases (Parvizi et al, 1978; Nairn, 1989) . In other words, the use of thick timber in CLT unfortunately promotes cracking compared to cross-laminated panels with more, but thinner layers. Attempts to ameliorate effects of precracks by applying glue to edges would be thwarted by natural formation of added cracks over time. The inescapable conclusions are that CLT structures must be designed with tools that recognize cracks and durability analysis of CLT must account for the rate of formation of added cracks and their role in changing structural properties.  \nFortunately, most of the methods needed for CLT analysis with cracks are already available from prior research on synthetic-material, cross-ply laminates (Hashin, 1985, 1986, 1987, 1988; Nairn, 1989) . Applications of synthetic cross-ply laminates include aerospace structures, bicycle tubes, ski poles, filament wound pressure vessels, and fiberglass pipes (the last two are not exactly cross laminated, but are close). Unlike CLT, synthetic cross-ply laminates are not manufactured with precracks, but like CLT, such laminates are prone to added cracks (referred to in the literature as “microcracks” or “transverse cracks”) caused by mechanical loads or by residual stresses (see reviews in (Nairn  \nJohn A. Nairn  \nOregon State University, Wood Science & Engineering  \n112 Richardson Hall, Corvallis, OR 97330, USA  \nTel.: +1-541-737-4265, Fax: +1-541-737-3385, E-mail: [John.Nairn@oregonstate.edu](John.Nairn@oregonstate.edu)  \nN22  \nM21  \nN 11  \nFig. 1 A three-layer CLT panel showing force (N) and moment (M) resultants for laminated plate theory and showing the 1-2-3 laminate axis system.  \nand Hu, 1994; Nairn, 2000)) . The conseque","cbCaihl3IcEAQ1hL","https://ap.wps.com/l/cbCaihl3IcEAQ1hL","pdf",293176,17,"English","# Introduction\n## Motivation: precracks and additional cracks in CLT\n## Prior composite and microcracking models\n# Alternative-Layer CLT Property Analysis\n## Baseline properties for crack-free panels\n## Three-layer panel setup and laminate axes","[{\"question\":\"What causes “precracks” in cross laminated timber (CLT)?\",\"answer\":\"CLT layers are bonded on their faces but usually not on edges within layers, so the exposed edges define periodic precracks in the composite.\"},{\"question\":\"How do additional cracks affect CLT performance?\",\"answer\":\"Additional cracks formed by differential thermal and moisture expansion can reduce mechanical and expansion properties and change structural durability considerations over the service life.\"},{\"question\":\"What analytical approach does the paper use to model CLT with cracks?\",\"answer\":\"It extends variational mechanics methods for aerospace composites to derive analytical solutions for in-plane mechanical, thermal expansion, and moisture expansion properties of a three-layer CLT panel as functions of crack density.\"}]","Cross Laminated Timber Properties Including Effects of Non-Glued Edges and Additional Cracks - Research article | PDF",43]