Advanced Modelling and Risk Analysis of RC Buildings with Sliding Isolation Systems Designed by the Italian Seismic Code

Double Curved Concave Surface Sliders (DCCSS) are seismic isolators based on the pendulum principle widely used worldwide. Coherently with European code, DCCSS do not include any mechanical elements as end-stopper. In case of displacement higher than those associated design earthquakes, inner slider runs edge sliding surfaces beyond their geometric capacity keeping ability to support gravity loads. this paper, advanced modelling and risk analysis reinforced concrete (RC) base-isolated buildings designed for medium high seismicity zones according Italian code has been assessed considering new construction existing structures retrofitted using isolation technique. Pushover analyses nonlinear dynamic including inelastic superstructure behaviour over-stroke system have carried out. Annual rates failure computed Usability-Preventing Damage (UPD) related inter-storey drift Global Collapse (GC) ultimate DCCSS. Moreover, is assumed an extra-displacement more 30% maximum geometrical displacement. Results pointed out that in GC UPD conditions occur almost at same intensity, while cases building, dominant limit state, being reached intensity level lower GC.