## 3 Results and Discussion
### Base Isolation Effectiveness Analysis  
Figure 9 shows the target responses of the maximum normalized base shear load (\(\hat{Q}_{0}^{max}\)), with maximum drift (%) and maximum displacement of the top rack \(u^{max}\) (cm) for the FBR (blue color) and BIR (green color). The responses are plotted against the parameters analyzed, height between pallets (\(H\)), span length (\(B\)) and the number of storage levels (\(N_{sl}\)), which are the parameters that both, FBR and BIR, have in common. The minimum seismic coefficient, \(C_{min}\) = 0.1 of the NCh2369 standard, is indicated with the red line for a seismic zone 3 (the one with the highest seismic risk). In Figure 9, it can be observed that there was a decrease in all the target responses, indicating that the use of the isolation system was effective in reducing seismic demand. In Figure 9a it can be observed that \(\hat{Q}_{0}^{max}\) was reduced by one order of magnitude when incorporating base isolation, with respect to the case with a fixed base. In addition, as a result of base isolation, practically all the racks should be designed with the minimum basal shear load requirements of the current standard. In Figure 9b,c, it can be observed that with the implementation of base isolation, the maximum drift and the maximum displacement had a reduction close to 85%, in relation to the same rack with a fixed base. In Figure 10, the sensitivity indices for the FBR and BIR are shown. In the case of the FBRs, the isolator's parameters (e.g., \(H_{ais}\), \(T_{a}\)) are not incorporated. From Figure 10, it can be seen that all the target responses were sensitive to the input parameters \(N_{sl}\), \(H\) and \(B\), with \(N_{sl}\) and \(B\) having the greatest and least influence on the outputs, respectively. In the case of the sensitivity indices of the BIRs (Figure 10a), it can be observed that the parameters that had the greatest influence on the maximum base shear load were \(H_{iso}\) and \(N_{sl}\), where \(N_{sl}\) and \(H\) showed a greater influence on the maximum drift and maximum displacement (Figure 10a,b). The latter was because these parameters made the racks more slender and, therefore, more flexible and susceptible to large displacements. From Figure 10, it can be seen that the parameter with the least influence on the target outputs or responses corresponded to the rack length in the direction parallel to the aisles (\(B\)). On the other hand, regarding the parameters of the isolation system, the isolation period (\(T_{iso}\)) had the least influence on target responses. The reason for this apparent anomalous behavior was explained in Section 3.1. The foregoing is consistent with the results shown in the figures in the previous sections. Seismic isolation seems to be a viable alternative to solve the problem of personal safety and property integrity due to the collapse of racks or falling objects as a result of earthquakes. [PERSON] et al. [42] present a summary of the experimental results of the seismic rack isolation device patented by [PERSON] et al. [11]. From the experimental tests, it was determined that the floor drift reached values of approximately 4% in the first level of the fixed base rack; however, in the rack with the Pellegrino isolation system, the floor drifts were less than 0.7% at all levels. Figure 10: Sensitivity indices. (**a**) maximum base shear load, (**b**) maximum drift and (**c**) maximum displacement of the top storage level. Figure 9: Scatter Plots of: (**a**) the maximum normalized base shear load (\(Q_{o}\)), (**b**) drift of the top of rack respect to its base, and (**c**) displacement (\(\mu^{max}\) ) of FBR (blue points) and BIR (green points). The red lines in the figures in row (**a**) indicate the minimum seismic coefficient of NCh2369, \(C_{min}=0.1\). With the implementation of the BIKD described by [PERSON] et al. [13], the numerical simulations of the analyzed industrial storage racks, it was determined that the decrease in floor drift was from 4.5% in the case of FBR, to values lower than 0.7% in the cases of BIR.