BASE-ISOLATION TECHNIQUESFOR THE SEISMIC PROTECTION OF RC FRAMED STRUCTURESSUBJECTED TO NEAR-FAULT GROUND MOTIONS

摘要

The main objective of this work is to compare different base-isolation techniques, in order to evaluatetheir 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 supplementalviscous dampers, or acting either in parallel or in series with steel-PTFE sliding bearings. A numericalinvestigation is carried out assuming as reference test structure a base-isolated five-storey reinforcedconcrete (r.c.) framed building designed according to Eurocode 8 (EC8) provisions. A bilinear modelidealizes the behaviour of the r.c. frame members, while the response of the elastomeric bearings issimulated by using a viscoelastic linear model; a viscous-linear law and a rigid-plastic one are assumed tosimulate the seismic behaviour of a supplemental damper and a sliding bearing, respectively. The seismicanalysis of the test structures, subjected to strong ground motions recorded near faults, is carried out byusing a step-by-step procedure.