Investigations of the application of gyro-mass dampers with various types of supplemental dampers for vibration control of building structures

A gyro-mass damper (GMD) is an inertia-based passive control device. It has a gear assembly that amplifies the rotational inertias developed in the gears and generates a resultant resisting force that is proportional to the relative acceleration at the end terminals of the GMD. The amplification provided by the gear assembly can be adjusted by changing the gear masses or the gear ratios of the compound gears. Although similar inertia-based devices have been successfully used for vibration mitigation of motor vehicles and optical tables, there are only a few studies that investigated their application in building structures. This number is even lower for the particular type of inertial damper that has been considered in this study, i.e., GMD. Unlike other types of inertial dampers, the supplemental energy dissipation component of GMDs is not built-in to the device and can be independently attached as an external component. This allows the design engineers to use this cost-effective device and select any available energy dissipation device to use in parallel. In this study, using a small-scale GMD, by considering the rotational inertias of the intermediate gears, characteristic equation which describes the relationship between the applied relative acceleration and the resulting resisting force is derived and experimentally verified. For the introduction of GMDs into building structures, three different configurations are evaluated: (i) stand-alone GMD, (ii) GMD-brace system, and (iii) GMD-Viscous damper-Brace (GVB) system. The structure-GMD interaction, considering these three configurations, is investigated in frequency domain and in time domain through energy balance equations and time history analyses. It is shown that by selecting the system parameters properly, GVB systems with nonlinear viscous dampers can effectively improve the seismic behaviour of the structure. This is discussed in more detail when the effects of the damper nonlinearities, as well as the various GMD equivalent mass, brace stiffness, damping values and selected ground motions are investigated. The key findings related to the design, implementation and performance considerations of these systems are provided.