This project is supported under NSF Announcement No. 90-23, "Repair and Rehabilitation Research for Seismic Resistance of Structures." This project studies the techniques for repair and strengthening of steel frames. Additional strength and ductility can be obtained by adding cover plates, welding, or other relatively unobtrusive techniques that allow strengthening to proceed while most of the building remains in use. This project is conducted as a joint research effort between the University of Washington, University of Minnesota, and Preece, Goudie and Associates with the University of Washington serving as the coordinating institution. The research addresses the question of the prediction of the strength, stiffness and ductility of older steel frames through a combined experimental and analytical study. The objective of this research is the development of rational methods and guidelines for predicting the seismic performance of older (as built) steel frames. Emphasis will be placed on the strength, stiffness, and ductility of the building, and it will focus on the types of steel structures used in the United States between 1900 and 1950. The study will provide design engineers with guidance in selecting analytical procedures for predicting the seismic resistance of these older structures, and as a result it will lead to economical rehabilitation of older steel structures.
