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Author
Lin, A. N. | Shenton, H. W., III
Title
Seismic Performance of Fixed-Base and Base-Isolated Steel Frames.
Coporate
National Institute of Standards and Technology, Gaithersburg, MD
Journal
Journal of Engineering Mechanics, Vol. 118, No. 5, 921-941, May 1992
Report
Paper 2282,
Keywords
steel frames | frame design | earthquakes | mathematical models | time histories | base shear | braced frame | moment frame
Abstract
The seismic performance of fixed-base and base-isolated concentrically braced and special moment-resisting steel frames are determined. The fixed-base frames are designed in accordance with the 1990 Structural Engineers Association of California (SEAOC) Recommended Lateral Force Requirements and Commentary, while the base-isolated frames are designed to 100%, 50%, and 25% of the SEAOC-recommended lateral force levels. Nonlinear time-history analyses, for 54 ground motion records, are then conducted. The number of yielded or collapsed frames, number of yielded elements, total and relative roof displacement, and isolation-bearing displacement are statistically evaluated. Comparable or better performance is achieved for the base-isolated braced frame designed to 50% of the SEAOC-recommended lateral force. Comparable performance is achieved for the base-isolated moment frame at various design force levels, depending on the performance criteria.