BASE-ISOLATION TECHNIQUES FOR THE SEISMIC PROTECTION OF RC FRAMED STRUCTURES SUBJECTED TO NEAR-FAULT GROUND MOTIONS

摘要

The main objective of this work is to compare different base-isolation techniques, in order to evaluate their effects on the structural response and applicability limits under near-fault earthquakes. In particular, high-damping-laminated-rubber bearings are considered, in case acting in parallel with supplemental viscous dampers, or acting either in parallel or in series with steel-PTFE sliding bearings. A numerical investigation is carried out assuming as reference test structure a base-isolated five-storey reinforced concrete (r.c.) framed building designed according to Eurocode 8 (EC8) provisions. A bilinear model idealizes the behaviour of the r.c. frame members, while the response of the elastomeric bearings is simulated by using a viscoelastic linear model; a viscous-linear law and a rigid-plastic one are assumed to simulate the seismic behaviour of a supplemental damper and a sliding bearing, respectively. The seismic analysis of the test structures, subjected to strong ground motions recorded near faults, is carried out by using a step-by-step procedure.