Friction pendulum system as a retrofit technique for existing reinforced concrete building

Friction pendulum system (FPS) is one of the most effective base isolation systems, which is widely used for seismic upgrading of existing buildings. FPS is almost always non-linear and often strongly non-linear, so a mechanical model of FPS bearing is of great importance in seismic analysis. In this paper, three different models of FPS bearing are described and a building severely damaged by the L'Aquila earthquake in 2009 is examined according to the latest Italian code. Then, a case study presenting briefly an innovative technique that is able to introduce base isolation on existing buildings is provided with reference to the use of FPS. Different kinds of analyses, including response spectrum analysis and linear and non-linear dynamic analyses, are performed under the life-safety limit state. Storey shear, inter-storey drift, effective stiffness and energy dissipation are the considered parameters to investigate the effectiveness of the retrofitting procedure and analysis techniques.