## 5 Conclusions  
Based on the well-developed simplified analytical models for FPBs and SRBs, this study attempts to numerically discuss their passive control performances, in terms of horizontal transmitted acceleration, isolation displacement, and post-earthquake residual displacement, which have been rarely studied before. To have objective comparison results, the first criterion adopted in this study for designing the FPB model was that at the horizontal isolation displacement identical to the maximum horizontal displacement response of the SRB model under a given seismic demand, the two different models have the same horizontal acceleration control performance. The second criterion was that at any horizontal isolation displacement, the two different models have the same energy dissipation capability. Some conclusions obtained from the numerical results and comparisons are made as follows. 1. This study briefly introduced and compared the features, equations of motion, and simplified analytical models of FPBs and SRBs. A large number of local and global ground motion records, including the so-called far-field and pulse-like near-fault ones, were adopted as the horizontal acceleration inputs for the numerical analysis on different SRB and FPB models designed based on the criteria considered. It is emphasized again that the purpose of the diverse ground motions considered and the models designed in this study was to obtain wide-ranging seismic responses of the models, rather than to passively reduce their seismic responses as small (or satisfactory) as possible or to propose optimum design approaches for FPBs and SRBs. Based on retaining the same horizontal acceleration control performance, the numerical results of four SRB models designed with different sloping angles and damping forces under the ground motions considered indicated that suppressing horizontal isolation displacement and reducing residual displacement were always two antithetic functions for SRBs simply designed with a constant sloping angle and damping force. In other words, under the same excitation, it is evident that the larger the damping force or, the smaller the sloping angle, the smaller the horizontal isolation displacement presented, but the more significant the residual displacement obtained. With the same horizontal acceleration control performance, the numerical results of hundreds of FPB models under the ground motions considered showed that the FPB models designed with a larger design displacement, a smaller curvature radius, and a smaller damping force might potentially have a better horizontal acceleration control and self-centering performances than those designed with a smaller design displacement, a larger curvature radius, and a larger damping force. On the premise of retaining the same horizontal acceleration control performance, the numerical results of two SRB models and hundreds of FPB models under the ground motions considered indicated that although the SRB models possess a unique feature--constant acceleration responses--the FPB models, on average, might potentially have a slight advantage over the SRB models in terms of horizontal acceleration control. Besides, the FPB models might also be potentially more effective than the SRB models in suppressing horizontal isolation displacement. As for the re-centering capability, the SRB model designed with a larger sloping angle is potentially better than that designed with a smaller sloping angle as well as the FPB models. In this research, the numerical study only considered two SRB models as the benchmarks for comparison with the FPB models might not be generalized enough. Nevertheless, some important quantitative results consistent with the theoretical bases and features of FPBs and SRBs, can still be obtained. These results are valuable for the whole picture of comparison of the two kinds of isolation bearings (i.e., FPBs and SRBs) or even the two types of hysteretic behavior (bilinear and twin-flag hysteretic behavior), as detailed in the fourth conclusion.