For a while now, engineers and scientists have been developing a wood-based product for use in construction projects that would otherwise normally require steel or concrete as the main structural support material. Obviously adding another growing market opportunity like this is an exciting development in the eyes of the wood products industry and bodes well for forest landowners, which is especially good news to hear during a period when markets have been a little squirrely.
This wood-based product, initially designed using softwood lumber, is known as Cross-laminated Timber (CLT), and is defined as “a large-scale, prefabricated, solid engineered wood panel. Lightweight yet very strong, with superior acoustic, fire, seismic, and thermal performance, CLT is also fast and easy to install, generating almost no waste onsite. CLT offers design flexibility and low environmental impacts. For these reasons, cross-laminated timber is proving to be a highly advantageous alternative to conventional materials like concrete, masonry, or steel, especially in multi-family and commercial construction.
“A CLT panel consists of several layers of kiln-dried lumber boards stacked in alternating directions, bonded with structural adhesives, and pressed to form a solid, straight, rectangular panel. CLT panels consist of an odd number of layers (usually, three to seven,) and may be sanded or prefinished before shipping. While at the mill, CLT panels are cut to size, including door and window openings, with state-of-the art CNC (Computer Numerical Controlled) routers, capable of making complex cuts with high precision. Finished CLT panels are exceptionally stiff, strong, and stable, handling load transfer on all sides.” (Source: www.apawood.org)
There is great enthusiasm developing around the new markets that this will open for softwood in the future, and we hardwood-minded folk have been hoping for inclusion in some way, shape or form in the CLT realm as well. Well, it seems that a particular effort made by Virginia Tech University has “cracked” that shell and gained some much-deserved attention, as they have designed and built a significant structure using CLT made from yellow-poplar, a fairly common hardwood found in parts of the eastern United States. Like our southern colleagues for softwood, we will welcome with open arms yet another marketplace for our valuable hardwood resource!
Below is a recent announcement from Appalachian Hardwood Manufacturers, Inc. (www.appalachianhardwood.org) that summarizes Virginia Tech’s recent news that their CLT structure built using hardwood has made it to the final rounds of a design/build competition. The “New River Train Observation Tower” link below provides some additional detail and pictures of this impressive project.
Along with the AHMI folks, we want to wish Virginia Tech well in the competition and hope this is just the beginning to a new-found outlet for our hardwood timber!
Dear AHMI member:
The first Appalachian Poplar cross-laminated timber structure in the U.S. is a finalist for the Architizer A+ Awards, a prestigious design competition focused on promoting and celebrating the year’s best architecture and products. Its mission is to nurture the appreciation of meaningful architecture in the world and champion those products that are integral to bringing great buildings to life and showcasing them to more than 400 million around the world.
The New River Train Observation Tower design-build by Virginia Tech students and faculty sets multiple benchmarks for CLT research, design, and construction globally. Rather than import softwood CLT into oversupplied, hardwood-dominate forest regions of the Eastern US, the project team decided to “think local” to reduce carbon costs.
Following a multi-year research, the team developed a structurally viable, high-performance, cross-laminated timber product made with Appalachian Yellow Poplar (YP-CLT) – and utilized it for the construction of the 30-foot high, 75-foot long publicly accessible tower. The YP-CLT product not only outperforms all other CLT available in the US market, but the project is also the first permanent building permitted for, and constructed with, hardwood CLT in the United States.
The train tower is composed of two structural CLT boxes bisected by a handicap-accessible path. The project provides views over the New River while educating the public about local-species CLT construction with hardwoods. The project sets research and design benchmarks as the first permanent building to be constructed with exterior-exposed structural hardwood CLT, as well as the first to utilize modular prefabrication for permanent hardwood construction.
The tower was the subject of a presentation at the 2019 AHMI Summer Conference. We wish them the best in the competition.
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