Monitored Seismic Behavior of Base Isolated Buildings in Italy

The experimental behavior of four base isolated buildings in Italy under seismic events of low energy at the site are shown. In the buildings with HDRBs the system is put in action also with very low accelerations at the site and the system filters the seismic actions. As a result the acceleration in the superstructure is not amplified and the superstructure is properly protected. This did not happen in the Jovine School at San Giuliano di Puglia, where the seismic action recorded was very low. In the building with CSSs, the accelerations were amplified to the top and the superstructure suffered high seismic actions. This behavior can be related to the static friction of CSSs. In all cases, the importance of an accurate non-linear analysis of their behavior under earthquakes of different magnitudes is pointed out, in order to guarantee that the seismic effects in the superstructure do not exceed those assumed in the design. The importance of the monitoring is evident. It allows a fast check of the seismic performance and so of the suitability of these structures to be kept operational during the emergency phase. A real time monitoring system is advisable.