2018 National Design Specification Changes
Have you reviewed the upcoming changes in the 2018 National Design Specification? Many changes resulted from changes to other reference standards, and it is important to note their impact on future wood design.
In the June 2019 SE University session, Lori Koch, PE, from American Wood Council, presented 2018 National Design Specification (NDS) Changes. Lori outlined and explained the changes included in each chapter and addressed how the wind load increases in ASCE 7-16 affected the NDS provisions.
Among the changes were new provisions for withdrawal design values for Roof Sheathing Ring Shank nails, as well as new design provisions for fastener head pull through values, both in response to the significant increases in Component and Cladding wind pressures in ASCE 7-16. Other significant changes include the addition of a volume factor, Cv, for structural composite lumber and revisions to the Cross Laminated Timber deflections provisions to be consistent with the terminology used in ANSI/APA PRG 320-2017.
In case you missed Lori’s presentation, or if you want to print a quick reference of the changes to the 2018 NDS, click here to access the AWC’s publication highlighting all relevant additions or alterations. At the end of the article, AWC has provided an Appendix: Summary of Changes, which details all the changes by chapter.