9416232 Hamburger Light industrial buildings of tiltup and reinforced masonry construction with panelized plywood roofs house thousands of workers in the Western U.S. In addition, strategic sectors of the Western U.S. economy including the aerospace, defense, electronics, banking, retailing and semiconductor industries are located within buildings of this construction. The performance of these buildings in a major regional earthquake clearly has major potential impact on the safety and welfare of broad segments of the society. This construction was shown to be vulnerable to earthquake induced collapses in the 1971 San Fernando earthquake. Building code changes were enacted in the mid-1970s were effective in mitigating this vulnerability. However, more than 400 such structures in the epicentral region of the Northridge earthquake, many conforming to these updated code requirements, experienced partial collapse, graphically demonstrating the inadequacy of current design approaches. This project examines the response of these commercial and light industrial buildings with wood framed roofs to near source ground motions, to determine the causative failure modes for these structures in the Northridge Earthquake, and to develop and assist in implementing effective design procedure changes to minimize the potential for catastrophic failures in future events capable of affecting the Los Angeles region, San Francisco Bay Area, Puget Sound region and other areas of intense development within seismically active zones. The findings of this research will be directly presented to code and standards development bodies, in forms which can readily be implemented. Recommendations will be developed to modify the design codes to provide adequate margin in the near source zones of earthquakes. ***
