Experimental Study of Collapse Limits for Wood Frame Shear Walls

摘要

Under extreme earthquake loading, light-frame wood building collapse is often caused by excessive interstory drifts at one or more story levels, leading to catastrophic P-A failure once the shear walls, and subsequently the entire structure, become unstable. This soft-story collapse mechanism has been observed in numerous earthquakes. Current performance-based seismic design methods for light-frame wood buildings typically uses very conservative drift levels to represent the near collapse deformation of wood frame building systems, such as the 3％ drift limit used in ACSE Standard 41 corresponding to a collapse prevention performance target. A series of full-scale collapse loading tests on wood shear walls was conducted in this study to identify the ultimate drift level at which P-Δ collapse will occur and is described in this paper. It was concluded that laterally braced wood shear walls can remain stable up to ～7-10％ interstory drift, depending on the magnitude of the vertical loading. If one considers the typical design range of gravity load commonly seen in multistory light-frame wood construction, assigning a single ultimate drift level of 7％ for light-frame wood building collapse limits appears to be justifiable based on the experimental results presented herein.