2015 NDS for Wood Construction – Now Including Cross-laminated Timber
Have you seen some of the new mid to high-rise structures that are using cross-laminated timber? While the product has been used in Europe since the 1990s, it has more recently become available in the US and Canada. Now, with the incorporation of this new wood product in the 2015 NDS for Wood Construction, you can expect its availability to increase as more designers become aware of its structural properties.
In the April 2017 SE University Core Session, Lori Koch, PE from the American Wood Council addressed changes in the 2015 NDS for Wood Construction. While some are minor revisions, the most significant change to the 2015 NDS is the incorporation of Cross-laminated Timber (CLT). Lori acknowledged this new wood product has been used internationally for some time, and the NDS felt it was important to include a new chapter for CLT in the wood products section of the code. Chapter 14, which referenced design of shear walls and diaphragms from the 2012 NDS, was relocated and included in Chapter 1, so with the addition of Chapter 10 for CLT, the 2015 NDS still remains at 16 chapters.
Also, new to the NDS is terminology for Laminated Strand Lumber (LSL) and Oriented Strand Lumber (OSL). Chapter 8 on Structural Composite Lumber reflects the inclusion of these products in ASTM D5456. Chapter 16, Fire Design of Wood Members, was revised to include CLT.
Additionally, there were updates to design values for southern pine within the NDS Supplement. For a complete listing of changes to the 2015 NDS including references to CLT, read this article from STRUCTURE Magazine or visit www.awc.org for complete information about the 2015 NDS.