9416354 Wood Tilt-up construction is widely used throughout the U.S. for low- rise industrial and warehouse facilities. Tilt-up buildings are economical to construct, however, they are susceptible to seismic damage. Approximately 25% of the tilt-up buildings in the epicentral area sustained structural damage during the 1994 Northridge earthquake. The objective of this project is to develop procedures for evaluating existing tilt-up construction and designing cost- effective rehabilitation schemes. Establishing a link between the structural characteristics of the building and the expected performance during an earthquake is emphasized in this study. In-situ tests of tilt-up buildings will be conducted to evaluate diaphragm stiffness, damping characteristics, and displacement distributions. The results of these tests, together with data collected on tilt-up buildings damaged in the Northridge earthquake, will be used to validate detailed analytical models under development. Existing retrofit requirements as well as the latest proposed changes will be reviewed and summarized. Typical rehabilitation schemes will be evaluated. Alternate analytical models and design methodology that are consistent with dynamic behavior of tilt-up construction will be developed. The results of this investigation will provide a basis for evaluating the seismic vulnerability of and developing cost- effective rehabilitation schemes for the large number of potentially hazardous tilt-up buildings throughout the U.S. This is a Northridge Earthquake project, involving complementary efforts between the University of Illinois and a consulting engineering firm, Wiss, Janney, Elstner and Associates. ***