Preliminary Numerical Analysis of the Vibro-Impact Isolation Systems Under Seismic Excitations

Isolated structures, in the presence of strong seismic events such as near-fault earthquakes, encounter problems related to large displacements due to the high flexibility of the isolation floor. The undesirable effects of large displacements can cause damage to isolation systems or excessive increase in superstructure accelerations and high interstory drifts that originate due to impact with adjacent structures if the seismic gap is insufficient. In order to limit these undesirable effects, the authors propose a new integrated design methodology of vibro-impact isolation systems (V-IISs) that aims to control large displacements while limiting the increase in accelerations due to the impact phenomenon. Therefore, the present work shows a preliminary numerical analysis on single-degree-of-freedom (SDOF) base-isolated systems subjected to a known seismic excitation (Irpinia earthquake) and constrained by two deformable and dissipative devices, called bumpers. The results show that V-IISs are able to mitigate large displacements by providing appropriate control of accelerations.