Collapse Limits for Wood Frame Shear Walls: An Experimental Investigation

Under extreme earthquake loading, light-frame wood building collapse is often caused by excessive inter-story drift at one or more story levels, which can lead to catastrophic P-Δ failure once the shear walls, and subsequently the entire structure, become unstable. Current performance-based seismic design for light-frame wood structures typically uses very conservative drift limits to prevent the collapse of the system, such as 3% drift in the ACSE Standard 41. The collapse drift limit for wood shear walls has not been studied extensively to date. A series of full scale collapse tests for wood shear walls was conducted and is presented in this paper with the objective of investigating the influence of wall configuration and gravity load on the ultimate drift level at which P-Δ collapse occurs. The shear wall collapse limit was found to be a function of wall strength and vertical load. Assigning a single ultimate drift level for light-frame wood building collapse limits appears to be justifiable based on the test results.