Full-Scale 3D Wall Bracing Tests

Beginning in early 2006, the APA Research Center expanded to include the capability of testing full-scale three-dimensional houses. This paper summarizes results of wall bracing racking tests from a full-scale 25 x 37.5 x 9-ft-tall three-dimensional wood frame house. Monotonic wall racking loads were applied at the corner of the structure in line with a single wall (the 37.5-ft-long wall). The concept of the setup was to investigate the wall behavior as part of a three-dimensional structure i.e. walls and roof are built around it. The roof diaphragm was flat. No finishes (i.e. gypsum, siding, roofing, etc) were installed and the walls were essentially bare with the exception of the applied bracing panels. A total of 23 different tests were conducted. Wall racking was generally limited to 1.5 inches in displacement to minimize damage and repair between tests. Repair was made after each test and the 23rd tests was a repeat of the 1st to compare results after repeated testing of some of the same framing components. The focus of these tests was primarily on the International Residential Code, IRC, wood structural panel type wall bracing. A number of variables were studied, including: 1 Hold-down devices in building corners, 2 Return corners, both 2 feet and 4 feet, 3 Panel placement at corners or away from corners, 4 Single diagonal 1 x 4 bracing, 5 Isolated wood structural panel bracing, 6 Continuous wood structural panel bracing, 7 Continuous wood structural panel bracing cut around openings, 8 Walls braced only by 6:1 aspect ratio portal frames, 9 Wall braced with 50 percent 6:1 aspect ratio portal frames mixed with other continuous wood structural panel bracing. This paper is a summary that discusses the global response of the structure to the applied loads. For more detailed information, including a detailed analysis of local wall responses, please refer to Martin et al.