Seismic Response of Uplifting Building Frame

Results are compared to the experimental response of a 9-story steel frame model tested on the Univ. of Calif., Berkeley, Calif., shaking table. The uplifting response is compared to the response for the same excitation with overturning ancharage provided, demonstrating a considerable reduction in the applied loading for the uplifting case. Extrapolation of the test results to a theoretical prototype frame indicate that a significant uplifting response would occur during a moderate, credible earthquake, even though not indicated by even conservative current building code seismic provisions. A rational consideration of the uplifting behavior is shown to be compatible with the concept of dual seismic loading criteria; a service loading that should produce no damage, and a maximum credible loading that should not result in catastrophic failure. A design including a rationally planned uplifting capability should stand a much beetter chancee of surviving a maximum credible earthquake in a functional condition.