Seismic Isolation Properties of Eccentricity Rolling Friction Pendulum

A theoretical analyzing approach about ERFPS(Eccentric Rolling Friction Pendulum System) is presented.It starts from formulation of the governing equation according to relative kinematics energy theorem in multiply body dynamics.This system consists of an eccentric roller which is placed in vicinity of two circular concave curve slides to form non-indented contacts.Computation results show that it has the three kinds of necessary capabilities required for an effective isolation system.The relatively long vibration period provides the seismic isolation capability,the gravity provides the reposition capability,and the rolling friction forces at contacting surface on top and bottom plate respectively,provides energy dissipation capability.It is shown that the inter-storey drift resulted from seismic action could be drastically decreased on buildings equipped with ERFPS system.If an optimum combination of cross-section eccentricity or slide radius and rolling friction coefficient is adopted,the seismic isolation efficiency could be as high as 90%.It is also shown that when eccentricity is about 3 cm or slide radius is in the range of 2～3 m and rolling friction coefficient is less than 0.01,ERFPS system exhibits both good energy dissipation capability and good reposition capability.