Passive antiseismic protections of multistorey building by controlled buckling of a steel base-isolation system (Q914446)

Preliminary performance data are given for a new type of auxiliary system for the base isolation of buildings under seismic disturbance. The system's behaviour relies on second order geometric effects with a response always within the elastic range. A characteristic elastic horizontal force vs. displacement curve was obtained with progressive stepwise reduction in stiffness. The advantage of the system compared with conventional reinforced rubber isolators is that high stiffness is maintained in response to wind action and there is a limit to the total force transmitted to the building under severe seismic action. And because energy is always absorbed elastically, the number of seismic events the system may withstand is not predetermined. The base system seems to offer encouraging advantages both in terms of a progressive stepwise reduction of the overall stiffness under increasing horizontal loads, and of an indefinitely elastic behaviour.