## 4 Analysis of Results
### Comparison of the Vertical Response of the Structure  
Figure 20 shows the structural deformation of the Dakai station during two kinds of earthquakes after setting three kinds of seismic isolation bearings. It can be seen from the figure that during the two earthquakes, the mid-span deflection of the structure reduced after the friction pendulum bearing was set at the bottom of the structure. Therefore, the structure still had a large deformation and did not achieve the seismic isolation effect [39]. After setting the ring spring bearing, the span of the structure dropped by 26.4 cm during the El Centro earthquake and by 29 cm during the Kobe earthquake, which was a substantial reduction but still did not meet the norm. The Chinese Standard (GB 50010-2010) [40] that when the flexural member exceeds 9 m, the mid-span deflection is limited to 1/300, which does not meet the seismic requirements after setting the ring spring bearing. Moreover, after setting the ring spring-friction pendulum bearing, the span deflection is below 5 cm and the span deflection ratio is less than 1/300 [41; 42]. Tables 4 and 5 show the axial pressures of the side walls and mid-pillars in different conditions. First, from the data in the two tables, we can see that the axial force on the mid-pillar reduced after setting the seismic isolation bearing, and the axial force on the mid-pillar could be reduced by about 20-40% by setting the friction pendulum bearing only. However, the results of the fourth condition showed that during the El Centro earthquake, the axial force of the mid-pillar after the friction pendulum bearing was set was 4410 kN. At this time, the axial compression ratio of the mid-pillar was 0.78. According to the requirements of the Chinese Standard (GB 50011-2010), the axial compression ratio of the  
Figure 20: Comparison between simulation results and the actual seismic damage to the subway station: (**a**) condition 3, (**b**) condition 4, (**c**) condition 5, (**d**) condition 6, (**e**) condition 7, and (**f**) condition 8.  
pillar of the frame-shear wall structure under the first-level seismic grade standard should be less than 0.75, so setting only the friction pendulum bearing cannot meet the seismic grade requirements. After setting the ring spring bearing, the axial force of the mid-pillar reduced by about 40%. However, the axial force of the side wall increased by four times, which means that although the axial force of the mid-pillar reduces after setting the ring spring, the other parts of the structure will still be damaged under the strong horizontal seismic action, combined with the deformation of the structure. It can be seen that under the two-way seismic action, the mid-pillar is the first to lose the vertical bearing capacity. In addition, most of the vertical seismic action is applied to the end of the side wall, so only setting the vertical seismic isolation bearing for the subway station structure does not have a good effect of seismic reduction. Finally, the structure still bears most of the seismic action. On the contrary, after setting the friction pendulum bearing, the axial force of the side wall significantly reduced, while the axial force of the mid-pillar did not significantly reduce. Moreover, a large deformation occurred in the span of the top plate of the structure, indicating that the mid-pillar of the structure was still subjected to most of the vertical load during the earthquake, and the bearing capacity of the side walls was not fully developed. Therefore, the seismic mitigation effect of the friction pendulum bearing and the ring spring bearing shows that setting the seismic isolation device in a single direction can only change the structure's force distribution and cannot absorb the energy during the earthquake well. After setting the ring spring-friction pendulum bearing, the advantages of the friction pendulum and the ring spring could be seen. The axial force of the mid-pillar reduced by more than 50%, while the axial pressure at the end of the side wall was slightly elevated.