Response of a Structure Isolated by a Couple System Consisting of a QZS and FPS Under Horizontal Ground Excitation

The study of vibration isolation devices has become an emerging area of research in view of the extensive damage to buildings caused by earthquakes. The ability to effectively isolate seismic vibrations and maintain the stability of a building is thus addressed in this paper, which evaluates the effect of horizontal ground excitation on the response of a structure isolated by a coupled isolation system consisting of a non-linear damper (QZS) and a friction pendulum system (FPS). A single-degree-of-freedom system was used to model structures whose bases are subjected to seismic excitation in order to assess the effectiveness of the QZS-FPS coupling in reducing the structural response. The results obtained revealed significant improvements in structural performance when the QZS-FPS uses a damper of optimum stiffness. A 30% reduction in displacement was recorded compared with the QZS for two signals, one harmonic and the other stochastic. In addition, the study demonstrated that the QZS-FPS combination can offer better control of building vibration in terms of horizontal displacements.