Reliability of woodframe residential construction subjected to earthquakes Yue Li a , Bruce R. Ellingwood b, * a Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI, 49931, United States b School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0355, United States Available online 12 September 2006 Abstract Most housing in the United States is light-frame wood construction (90% nationally, and 99% in California). Residen- tial construction in the United States typically has received little or no structural engineering. The performance of wood residential construction to earthquake effects was apparent in the 1994 Northridge Earthquake, and underlines the need for new approaches to enhance building performance through improved prediction, evaluation and design methods. In this paper, methods of stochastic nonlinear dynamic analysis are used to simulate the behavior of lateral force-resisting shear wall systems typically found in residential construction subjected to earthquakes. The probability that shear wall drift lim- its are exceeded for uniform hazard earthquake ground motions with various return periods and intensities can be esti- mated from this analysis and can be related to performance levels for residential occupancy that have been suggested in concurrent research on performance-based engineering. The probability of failure under a spectrum of possible earth- quakes is determined by convolving the structural fragility derived from the above analysis with the seismic hazard spec- ified by the US Geological Survey. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Buildings; Earthquakes; Fragility; Probability; Reliability; Structural engineering; Wood construction 1. Introduction The vulnerability of wood residential construction to earthquake ground motion was clearly apparent dur- ing the 1994 Northridge Earthquake and its aftermath, where the property losses ($20 billion) to residences far outweighed the loss to any other single type of building construction. Furthermore, more fatalities (24 of 25) and injuries occurred in light-frame buildings than in all other types of buildings combined. These failures highlight the impact of deficiencies in current residential building practices aimed at mitigating risk from nat- ural hazards. Light-frame wood residential construction in the United States traditionally has been non-engi- neered. There is an obvious need to develop new concepts, methodologies and design practices to assess and enhance the performance of wood frame construction during earthquakes. At a fundamental level, such 0167-4730/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.strusafe.2006.07.012 * Corresponding author. Tel.: +1 404 894 1635; fax: +1 404 894 2278. E-mail address: bruce.ellingwood@ce.gatech.edu (B.R. Ellingwood). Structural Safety 29 (2007) 294–307 www.elsevier.com/locate/strusafe STRUCTURAL SAFETY