Vehicular Impact Performance Evaluation Method for CFST Columns Based on Residual Deformation

Accidents of vehicles hitting columns have happened frequently in recent years. Hence, it becomes important to evaluate the performance of columns under vehicle impact. This paper presents a residual deformation-based method for the vehicular impact performance evaluation of concrete-filled steel tubular (CFST) columns. Before that, a finite-element (FE) model was developed to simulate the responses of CFST columns under vehicle impact and post-impact axial compression and validated by reported tests. Based on the FE model, five performance levels of CFST columns under vehicle impact were divided according to numerical damage states and corresponding residual axial capacity ratios. In the presented performance evaluation method, a residual deformation, i.e., the ratio of the residual deflection at the mid-height to the corresponding height, which is related to the residual axial capacity ratio, was selected as the evaluation index. For the residual axial capacity ratio of 0.85–1.00, 0.60–0.85, 0.40–0.60, 0.20–0.40, and 0–0.20, the residual deformation ranges 0–1.5 × 10^–2, 1.5 × 10^–2–7.5 × 10^–2, 7.5 × 10^–2–1.4 × 10^–1, 1.4 × 10^–1–2.5 × 10^–1, and > 2.5 × 10^–1, respectively. In addition, an analytical model for the residual deformation was proposed. Comparisons show that analytical performance levels by the presented method are completely consistent with numerical results. Due to being residual deformation-based, the presented method can be used for both the performance prediction of CFST columns before vehicle impact and the performance assessment of CFST columns after vehicle impact.