# Artificial Intelligence Algorithm-Based Arrangement Optimization of Structural Isolation Bearings
## 3 Optimal Arrangement Method of Isolation Bearings
### Calculation Procedure of Isolation Structure  
During seismic isolation design, if eccentricity of the isolation bearings stiffness center and the center of gravity of the superstructure is too large, the relative displacement between the superstructure and the isolation layer will be large under a seldom-occurred earthquake, which would cause the isolation bearings to be destroyed early or even cause the superstructure to continuously collapse, making it impossible for the isolation bearings to fully exert their effect. Hence, eccentricity of the stiffness center of isolation bearings and the center of gravity of the superstructure is clearly specified in the Chinese design code [38]: the eccentricity under the seismic fortification intensity should not be greater than 3%, and it would be better for the stiffness center of the isolation layer to be close to the center of gravity of the superstructure. Here, seismic fortification intensity is applied as the design reference for seismic fortification in a region. In general, this seismic intensity represents design seismic action with 10% exceedance probability in 50 years in Chinese design code, corresponding to design earthquake ground motion in International Building Code [41] and no-(local-) collapse level in Eurocode 8 [39]. Accordingly, in this paper, eccentricity is also taken into account as a constraint condition for isolation optimization analysis. In a conventional isolation scheme, the layout of isolation bearings is typically arranged based on previous experience and trial calculations. Then, according to the gap between the predetermined design target and various design indicators of isolated structures under the action of fortification earthquakes and rare earthquakes, the isolation \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Serial Number** & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** & **11** & **12** \\ \hline \multirow{3}{*}{weight coefficients} & \(\alpha\) & 0.2 & 0.8 & 0 & 0.2 & 0.4 & 0.6 & 0.8 & 0.2 & 0.4 & 0.2 & 0.2 & 0 \\  & \(\lambda\) & 0 & 0 & 0.2 & 0.2 & 0.2 & 0.2 & 0.4 & 0.4 & 0.6 & 0.8 & 0.8 \\  & \(\gamma\) & 0.8 & 0.2 & 0.8 & 0.6 & 0.4 & 0.2 & 0 & 0.4 & 0.2 & 0 & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Weight coefficient combinations. bearing scheme will be iteratively adjusted. To improve this process, Convolutional Neural Network and Hunter-prey optimization specifically elaborated in Sections 3.2 and 3.3 are applied in the selection of types and sizes of bearings to acquire an isolation scheme more intelligently, even for freshman without any experience. Afterwards, Python is utilized to update the isolation scheme in the structural model via API of ETABS to perform calculation procedure. During this period, the specific processes of each iteration are as follows:  
1. Selecting initial bearings: the isolation bearings that meet the requirements are preliminarily chosen based on vertical reaction at column bottom under the action of the standard gravity load of the non-isolation structure model, limit value of bearings compressive stress, and yield force of bearings listed in Tables 1 and 2. 2. The isolation model is established in the analysis software according to the bearing parameters. In this paper, the optimization calculation is performed with the ETABS, which is manipulated by Python through API interface. For LNR, LRB bearings, the Rubber isolator element is used to create tensile and biaxial shear model. Moreover, on account of the significant difference between compression and tensile stiffness, the compression constitutive relation is reflected by the Gap element.