## 4 Sine Sweep Testing  
The first step of the experimental investigation was the sine sweep testing. The structure models with and without the PBs were mounted on the shaking table and subjected to sinusoidal excitation with increasing frequency ranging from 0.1 up to 15 Hz. The tested models were instrumented with uniaxial  
Figure 8: Fixed-base (**a**) and base-isolated (**b**) two-storey structure model. Figure 7: Fixed-base (**a**) and base-isolated (**b**) single-storey structure model. accelerometers to record the acceleration-time histories at different levels. The time-acceleration histories recorded at the top of the tested models are shown in Figures 9 and 10. In the case of the single-storey structure, the peak response acceleration is equal to 7.74 and 3.25 m/s\({}^{2}\) for the fixed-base and the isolated model, respectively. On the other hand, the peak response acceleration for the two-storey structure is equal to 4.42 and 2.44 m/s\({}^{2}\) for the fixed-base and the isolated model, respectively. The results obtained clearly indicate that the application of the prototype PBs results in a considerable improvement of dynamic characteristics of the experimental models. Period elongation and additional damping associated with implementing PBs resulted in a significant decrease in lateral accelerations experienced by the tested models during sinusoidal excitation, which can be observed on the basis of time-acceleration histories presented in Figures 8 and 9. The reduction in peak lateral accelerations recorded at the top of the experimental models due to the application of the isolation devices was determined to be approximately 58% and 45% for the single-storey and two-storey structure models, respectively. earthquake of 1940, the San Fernando earthquake of 1971, the Loma Prieta earthquake of 1989, the Northridge earthquake of 1994, and finally the Polkowice (Poland) tremor of 2002 as an example of mining-induced seismicity, which is also a major concern of professional and research communities (see, for example, [36]). The tested models were instrumented with uniaxial accelerometers to record the acceleration-time histories at different levels. The effectiveness of the PBs in reducing structural vibrations under seismic excitations was verified by comparing the peak accelerations experienced at the top of the tested models. The time-acceleration history plots recorded at the top of the tested models are also shown in Figures 11 and 12. The peak accelerations recorded at the top of the analyzed single-storey and two-storey structure models, with and without the PBs, are briefly reported in Tables 1 and 2, respectively. Figure 11: Time-acceleration history plots for the fixed-base (blue) and base-isolated (red) single-storey model during different earthquakes: the 1940 El Centro earthquake (**a**,**b**), the 1971 San Fernando earthquake (**c**,**d**), the 1989 Loma Prieta earthquake (**e**,**f**), the 1994 Northridge earthquake (**g**,**h**), and the 2002 Polkowice mining tremor (**i**,**j**). Figure 12: _Cont._  
Figure 12: Time-acceleration history plots for the fixed-base (blue) and base-isolated (red) two-storey model during different earthquakes: the 1940 El Centro earthquake (**a**,**b**), the 1971 San Fernando earthquake (**c**,**d**), the 1989 Loma Prieta earthquake (**e**,**f**), the 1994 Northridge earthquake (**g**,**h**), and the 2002 Polkowice mining tremor (**i**,**j**).