## Data Collection  
Researchers worldwide have conducted numerous pseudo-static cyclic tests on RC columns to investigate the hysteretic behavior and seismic performance of such structural components in buildings and bridges. To provide data for training the ANN model, the cyclic test results of RC columns were collected from the NEEShub database [26], PEER database [27] and other published studies based upon the following criteria:  
1. The shape of the cross section of the RC columns should be rectangular; others like circular columns are not included in this study. 2. The RC columns only sustained constant axial loading and unidirectional cyclic lateral force. Cyclic tests of the RC column under biaxial lateral or variable axial loads are excluded. 3. A complete loading process was applied to the specimens until failure; the load carrying capacity of the specimen decreased by more than 20% compared to the peak strength. 4. Details of the specimens are available, such as the geometrical size and reinforcement, as well as experimental results of the hysteretic curves. 5. Normal concrete was used in the manufacture of the specimens, without additives such as steel fiber. A total of 1163 cyclic test results of RC columns were collected to build a database for training, testing and validating the ANN model. Details of the selected specimens, including the data source and geometrical size, are listed in the Appendix A. It can be observed that the main features of the selected columns have a relatively wide distribution. The numerical simulation of RC columns may depend upon many factors, such as the material properties, geometrical configuration, reinforcement layout and loading protocol. Figure 1 shows a schematic diagram of a typical cantilever column, illustrating some of these factors, as well as its LP model. The section width (\(B\)) and depth (\(D\)) is defined as the section size which is perpendicular and parallel to the lateral force, respectively. It should be noted that a cantilever and fixed-end columns are two typical structural components used for civil structures. For simplicity, this study mainly focused on cantilever columns, which are widely used in bridge piers; the geometrical size and test results of the fixed-end columns were modified by assuming that the inflection point of the columns occurs at the half height of the column. As illustrated, the optimal feature subset is selected by the genetic algorithm (GA) method, then used to train the ANN model. It can help determine the parameters of the LP model for RC columns. As is known, there are many factors influencing the performance of RC columns, some of which are dependent. For example, the effective depth (\(d_{e}\)) can be calculated by \(B\), \(D\) and the effective cover thickness (\(d^{\prime}\)). Although the independent parameters are simple and easily accessible, the derived parameters may be more effective in some cases. Consequently, the potential influencing features are collected for feature selection, which are categorized into six groups as listed in Table 1. It can be observed from the table that a total of 24 features were included, in order to investigate their effects on RC columns. As for the modeling, the LP model of RC columns is usually represented by the bi-linear and tri-linear model [28]. As shown in Figure 2, the strength and the yielding, capping and ultimate deformation of the RC columns can be defined according to the method using the hysteretic curves obtained from cyclic tests. The strength is defined as the peak point when the resistance force reaches its maximum value. According to statistical results by [PERSON] et al. [29], the yielding deformation can be roughly estimated as that corresponding to 85% of the peak strength, and the ultimate deformation is obtained from the drift when the resistance drops to 20% of the peak strength [6]. It should be noted that the actual test results of the hysteretic curve cannot always achieve perfect symmetry in both the positive and negative directions.