Performance Comparison of Conventional Machine Learning and Stacking Ensemble Models for Predicting Peak Seismic Displacement Response of Columns Considering Geometric Parameters
This study comparatively analyzes conventional machine learning models and a stacking ensemble model for predicting the peak displacement response of concrete columns under seismic loading. Using geometric parameters, material properties, and ground motion characteristics as inputs, a database of 1,080 cases was constructed via finite-element time-history analysis. Hyperparameter optimization was applied to six conventional machine learning models based on tree-based, kernel-based, and neural network approaches. A stacking ensemble is constructed with Extra Trees and XGBoost as base models and RidgeCV as the meta-model, and its optimal configuration is derived by examining meta-model selection, passthrough application, and the number of cross-validation folds. Predicted peak displacement responses were converted into drift ratios normalized by column height to evaluate predictive performance across models. The tree-based models show stable performance with a MAPE of 3-4%, while the stacking ensemble achieves the lowest error rate at 2.68% MAPE. Interval-based analysis shows that the stacking ensemble yields lower error rates than conventional machine learning models across a range of geometric parameters, including column height, cross-sectional dimensions, and aspect ratio, confirming stable predictive performance under variations in these parameters.