# Artificial Intelligence Algorithm-Based Arrangement Optimization of Structural Isolation Bearings
## 4 Example Analysis
### Structure Model  
The Location of a structure has a seismic fortification intensity of 8 degrees 0.2 g with site Class II, and design earthquake group 2. According to the Chinese design code [43], a 9-story concrete frame structure is designed, with standard story height 3.3 m, and isolation story height 2 m. As is shown in Figures 5 and 6, the structural plane and elevation layout, the structure has five transverse spans--which are 4.6 m, 8.2 m, 3.5 m, 8.2 m, and 4.6 m, respectively--and eight longitudinal spans of 6.3 m \(\times\) 8 m. The main beam size is 300 mm \(\times\) 700 mm and the thickness of the slab is 120 mm, while column sizes of 1-3 layer, 4-6 layer, and 7-9 layer are 1000 mm \(\times\) 1000 mm, 900 mm \(\times\) 900 mm, and 800 mm \(\times\) 800 mm, respectively. The concrete strength grade of the beam and slab is C35, and C40 for column. The floor live load, floor dead load, and design basic wind pressure are 2.5 kN/m\({}^{2}\), 3.5 kN/m\({}^{2}\), and 0.3 kN/m\({}^{2}\), respectively. The structural damping ratio is 0.05, and the compressive stress limit value of isolation bearings is 12 Mpa. More details and design parameters are listed in Table 4.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Design Parameters** & **Values** & **Design Parameters** & **Values** \\ \hline Fortification intensity & 8 degrees & Peak acceleration & 200 gal \\ Characteristic period & 0.40 s & Design earthquake group & 2 \\ Column section in 1–3 layer & 1000 mm \(\times\) 1000 mm & Site class & II \\ Column section in 4–6 layer & 900 mm \(\times\) 900 mm & Floor thickness & 120 mm \\ Column section in 7–9 layer & 800 mm \(\times\) 800 mm & Isolation floor thickness & 180 mm \\ Main beam section & 300 mm \(\times\) 700 mm & Secondary beam section & 250 mm \(\times\) 500 mm \\ Story height & 3300 mm & Height of isolation layer & 2000 mm \\  & C35 with compressive & & HRB400 with yield \\ Concrete strength for beam and floor & strength = 16.7 MPa & & strength = 400 MPa \\  & C40 with compressive & & Floor live load & 2.5 kN/m\({}^{2}\) \\ Concrete strength for column & strength = 19.1 MPa & & \\ Design basic wind pressure & 0.3 kN/m\({}^{2}\) & Floor dead load & 3.5 kN/m\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Design parameters for the example structure.  
Figure 5: Structural plane layout (unit: mm): letters A–F represent serial numbers of lengthwise axis.  
According to the design response spectrum and calculation results of non-isolation and preliminary base-isolated structure models under a fortification earthquake, two artificial waves and five natural waves are selected, the spectrum curves of which are shown in Figure 7. The peak amplitude of seismic wave acceleration is adjusted to 200 gal under the fortification earthquake, and 400 gal under the rare earthquake. Here, the fortification earthquake is a design seismic action with 10% exceedance probability in 50 years in the Chinese design code [43], corresponding to design earthquake ground motion in the International Building Code [41] and no-(local-) collapse level in Eurocode 8 [39]. The rare earthquake is design seismic action with 2-3% exceedance probability in 50 years in the Chinese design code [43], corresponding to the maximum considered earthquake ground motion in the International Building Code [41].  
Figure 6: Structural elevation layout.  
Figure 7: Diagram of seismic wave response spectrum: scale factor for natural waves: Chi-Chi, Taiwan-04_NO_2717: 0.34, Borrego Mtn_NO_40: 0.62, Morgan Hill_NO_471: 0.29, Gilroy_NO_2039: 0.14, Manjil, Iran_NO_1639: 0.16.