APA-The Engineered Wood Association has published a new System Report, detailing a simplified wall bracing method using continuous wood structural panel sheathing. APA System Report SR-102 provides building officials, builders and designers with an enhanced approach and the supporting technical information to brace walls of single-family houses in areas of low wind and seismicity, while providing more flexibility for building design and construction.
In developing the System Report, APA's technical staff enhanced the 2012 International Residential Code (IRC) simplified wall bracing provisions (Section R601.12) to increase their applicability to a larger percentage of home designs. To provide greater architectural latitude, APA's Simplified Bracing Method calls for continuously sheathed wood structural panel bracing with an increased, yet common, sheathing thickness (7/16"), a larger nail (8d), and a closer (4 inches) nailing schedule. This approach increases the performance of the bracing panels on the first story of a two-story structure due to the additional restraint provided by the mass and stiffness of the structure above, through strength from increased fastening, and through the use of thicker sheathing. The improved performance that this bracing method achieves means that it can be used on a greater percentage of homes with multiple window and door openings on the front and back elevations, than is allowed with the simplified bracing method in the IRC.
"APA's objective was to further streamline the simplified wall bracing provisions in the 2012 IRC and develop a method that would be easier for builders and designers to apply. We also recognized the need for more design flexibility in the placement of braced wall lines around window and door openings," explained Dr. BJ Yeh, P.E., APA's Technical Services Director. The System Report greatly reduces the complicated wall bracing provisions in the 2012 IRC from 34 pages to 7 pages.
The recommendations in the System Report are based on a multi-year research and testing initiative carried out by the Association. A variety of wall assemblies were tested at the APA Research Center in Tacoma, Washington, to characterize the lateral performance of walls that are continuously sheathed with 7/16" minimum wood structural panels fastened with slightly larger nails and a tighter nailing schedule.
The Simplified Bracing Method detailed in the System Report is for use only with continuously sheathed wood structural panel bracing, and is applicable to construction in many areas of the country. The report explains how to design for adequate bracing and includes three tables that builders and designers can easily use to compute the length of braced wall sections in each wall line.
For more information about APA's Simplified Wall Bracing Method, and for a free download of System Report SR-102: APA Simplified Wall Bracing Method Using Wood Structural Panel Continuous Sheathing, go to www.PerformanceWalls.org. Printed copies of the report and educational training