The present study deals with energy pumping phenomenon which consists in passive irreversible transfer of energy from a linear system to a strong nonlinear attachment [
]. The aim is to be able to design efficient nonlinear energy sink devices (for example with cubic nonlinearity [
]) in particular to attenuate modal responses for transient and steady vibrations. The main point is the strong nonlinear coupling. Contrary to the case of standard tuned mass dampers, energy transfer is irreversible because of modal localization which prevents the energy from being released back to the main structure. Various results (theoretical, numerical and experimental) about energy pumping based on recent works are given. Thus, the phenomenon is studied for different excitations: transient and periodical. For transient excitations, the case of seisms is also considered with an indicator of efficiency (i.e. the Arias Intensity). Moreover, advantages of such a system are carried out. The theoretical findings are tested and verified experimentally using appropriately designed reduced scale buildings with one or four floors. In particular, a comparison with an optimized classical linear tuned mass damper (like Frahm damper) can be done. With strong cubic coupling, the features (in particular the modes) of the system are not modified. Indeed, experimental verification has shown the efficiency of energy pumping compared to classical linear tuned mass damper. Not only is the phenomenon robust theoretically but it is possible to implement it practically with a small realistic building model.