On Passive Vibration Control of Buildings Against Earthquakes

The strategy of passive vibration control of structures for their protection against earthquake is reviewed. Attention is given to the base isolation methodology for earthquake resisting design.Several earlier and recently proposed base isolation devices for seismic protection of buildings are described. It is shown that using properly designed base isolation systems can effectively reduce the acceleration transmitted to compact stiff structures during earthquakes. Examples of responses of multistory buildings with and without base isolation system subject to earthquake excitations are presented. A small-scale experimental setup for testing the performance of rubber bearing isolation system is described. The setup consisted of a three degree-of-freedom structure that was excited at its base with a shaker. The unprotected building response to actual earthquake acceleration was recorded and is compared with that for the structure with the passive isolation system. A scaling procedure was used in the experimentation. Computer simulations were used to evaluate the response of the building model to the earthquake base excitation for the fixed base case and the one with a passive isolation system. The Computer simulation results are compared with the experimental data and reasonable agreement is observed. It is shown that the rubber bearing passive isolation system is highly effective for protecting the building from seismic ground excitation. Furthermore, the scaling procedure is useful for performing small-scale laboratory experiments for seismic response of structures.