Wednesday, October 29, 2014
The American Wood Council 2015 “National Design Specification® (NDS®) for Wood Construction” and “Special Design Provisions for Wind and Seismic” (SDPWS) standards have been approved as American National Standards by the American National Standards Institute (ANSI). Both standards are referenced for compliance with the International Code Council’s upcoming 2015 “International Building Code” (IBC).
Updated standards will be available in electronic format on the AWC website on or before Dec. 1, 2014. Print versions of the standards are expected to be available for purchase in early 2015. Primary changes to these standards are:
2015 NDS – A new product design chapter for cross-laminated timber (CLT) includes the design of CLT members, connections and fire design. Another significant change is new provisions that explicitly permit Structural Composite Lumber (SCL) to be designed for fire requirements using NDS Chapter 16. The 2015 NDS Supplement, packaged with the NDS, contains updated design values for visually-graded southern pine and mixed southern pine dimension lumber.
2015 SDPWS – New provisions have been added for seismic and wind design of cantilevered wood-frame diaphragms that provide important design clarifications, especially for design of “corridor-only” multi-story wood-frame structures. There are also revisions to the protocol for determining equivalent deformation-based shear distributions that allow more efficient seismic design of shear walls containing high aspect ratio shear walls.
Designers are urged to begin using provisions of the new standards pending approval by the authority having jurisdiction. Many code officials will allow the use of new standards, particularly when they are developed through a consensus process.
“These are exciting revisions, and through their reference in the International Building Code, will allow traditional and engineered wood products to be more easily used in the United States,” said AWC President and CEO Robert Glowinski. “Our work does not end with these revisions, however. To make these code-referenced standards the most user-friendly they can be, we will now be developing supporting publications such as commentaries, revising technical reports and design aids, and conducting further research to ensure continued widespread acceptance of wood in construction.”