## 2 Database Collection and Processing  
The collected database contains a total of 97 datasets comprising results from tests on square, rectangular, and strip footings of various sizes conducted in sand beds with different unit weights (dry unit weight, \(\gamma_{\mathrm{d}}\) or effective unit weight, \(\gamma^{\prime}\)). To improve the model's performance, the data are evenly distributed, ensuring an equal number of samples for large and small-sized footings. Out of the 97 datasets [14; 60], 47 are derived from load tests on large-scale footings from different references [14; 60; 61; 62]. The remaining 50 datasets are from load tests on smaller-sized model footings, as reported by [PERSON] [63]. For the large-scale tests conducted at the DEGEBO test area in Berlin, submerged unit weights (\(\gamma_{\mathrm{d}}\) or \(\gamma^{\prime}\)) are utilized due to the submerged conditions during testing [14; 60]. The angle of shearing resistance reported by the respective authors is adopted for the analysis, despite some differences in the mobilized angle of shearing resistance at failure between axisymmetric and plain strain conditions. Nevertheless, these differences do not exceed 10% [14; 60]. In the case of laboratory model tests, the internal friction angles used are obtained from direct shear tests conducted at very low normal stresses, which also includes the effect of dilation. Regarding the determination of ultimate load, for large-scale footings, it is defined as the load corresponding to the point where the slope of the load settlement curve is at its minimum. For smaller-sized model footings, it is defined as the load corresponding to the point of break of the load settlement curve in a log-log plot. Figure 1 shows the distribution of the database. Figure 2 illustrates the influence of the foundation depth on the foundation load. From these diagrams, it can be observed that the bearing capacity of the shallow foundation increases with the increasing foundation depth. Prior to utilizing the existing database, a thorough check for inappropriate data was conducted. To accomplish this, a box plot for the output parameter was generated, and Figure 3 displays the results. Following the examination, 22 datasets were identified as inappropriate and subsequently removed from the overall database. The refined database consists of 75 suitable datasets, and their corresponding box plot is depicted in Figure 3.  
Table 1 presents the distribution of the utilized database after the exclusion of outliers. The data reveal valuable insights into the statistical characteristics of each variable. The ultimate bearing capacity of the foundation, represented by q\({}_{u}\), varies significantly across the datasets, ranging from 58.500 kPa to 464.000 kPa, with a mean value of 211.274 kPa and a standard deviation of 108.959 kPa. On the other hand, the foundation width (B) displays a relatively tighter distribution, ranging from 0.059 m to 0.600 m, with a mean of 0.250 m and a standard deviation of 0.195 m. Similarly, the foundation depth (D) exhibits a narrow range, varying from 0.000 m to 0.500 m, with a mean value of 0.098 m and a standard deviation of 0.106 m. The aspect ratio (L/B), calculated as the ratio of foundation length to width, shows wider variability, ranging from 1.000 to 6.000, with a mean of 3.409 and a standard deviation of 2.269. The unit weight of the soil (\(\gamma_{\mathrm{d}}\) or \(\gamma^{\prime}\)) displays variations across the datasets, ranging from 9.850 kN/m\({}^{3}\) to 17.100 kN/m\({}^{3}\), with a mean value of 14.615 kN/m\({}^{3}\) and a standard deviation of 2.625 kN/m\({}^{3}\). Similarly, the internal friction angle of the soil (\(\phi\)) exhibits moderate variability, ranging from 34.000\({}^{\circ}\) to 42.500\({}^{\circ}\), with a mean value of 38.363\({}^{\circ}\) and a standard deviation of 2.691\({}^{\circ}\). The information provided in  
Figure 3: Process of removing outliers using plotting boxplots for (**a**) initial database and (**b**) final database.