Is Wood the Future of Materials?

Author
Mark Atwater posted on March 04, 2014


Think of three advanced materials. Some things that might come to mind are carbon fiber, superalloys or nanomaterials such as graphene. Most often, wood will not be high on that list. Although wood is not new, some advanced engineering is making it perform new tasks.

Cross-laminated timber (CLT) is helping wood find its way back into commercial construction. Although residential construction uses wood framing extensively, for larger structures incorporating many levels, it simply doesn’t offer the necessary support.

If you need to build a tall building, you need strong, durable materials. Steel and concrete have done wonders for skyscraper design. The problem with these materials is that they require considerable energy to produce. The majority of that energy is sourced from nonrenewable fuels.

Wood requires energy too. Engineered wood products such as oriented strand board (OSB), medium-density fiber board (MDF), plywood, etc. all require more energy than dimensional lumber because they incorporate additional steps in manufacturing and secondary bonding materials. CLT requires significant processing beyond chopping a tree down, but it still has a lot to offer.

What makes CLT different from other mass building materials is that it’s produced from a renewable material. First, the trees must grow. In doing so, they will be actively removing carbon dioxide from the atmosphere. That is something inorganic materials cannot hope to achieve.

The tallest modern timber building in the world, the nine-story Stradhaus, is claimed to store 186 tons of sequestered carbon in its wooden structure. Looking for sustainable options in building, architecture firms are taking the advancements in timber materials seriously with sights on building higher in the future.

CLT can make this happen because it is engineered to withstand greater and more varied forces. A single board, like the tree it came from, is anisotropic. The properties parallel to the grain are much different than across it.  That is one of the benefits of plywood in which each layer is specifically oriented (often in 90 degree increments). This principle of engineering through grain orientation is applied to CLT as well.

Unlike plywood, CLT uses full-size, dimensional lumber which is oriented and glued at right angles. The process and product are essentially scaled-up plywood sheets capable of handling much more load.

The CLT panels are prefabricated, which speeds construction. Due to their dense construction, the panels are also fire-resistant and aid in insulating the building.

CLT construction is a variant on the proven performance of plywood. The increase in scale allows for a commensurate increase in project size. Although not appropriate for every endeavor, it is allowing for wood to make an encore appearance in commercial construction. As it turns out, you can teach an old dog new tricks.

The video below discusses more about CLT (with some salesmanship).

For further details logon website :
https://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/7261/Is-Wood-the-Future-of-Materials.aspx