## 2 FE Model Validation
### Comparison of the Simulation and Test Results under a Horizontal Impact  
Figure 10 compares the FE results (the equivalent plastic strain contour map of concrete) and the experimental damage states of each specimen [16]. The FE results show agreement with the three experimentally observed damage states, including (I) a slight damage state (in which only fine cracks were observed on the concrete surface, and all longitudinal rebars were still in the elastic state), (II) a moderate damage state (in which the concrete cracked and the tensile longitudinal rebars yielded), and (III) a complete damage state (in which the specimen underwent flexural failure of the normal cross-section; wide flexural cracks were clearly observed in the bottom area; the tensile longitudinal rebars had yielded; and the concrete cover in the compression zone was crushed). Figure 11 shows the experimental [16] and numerical simulation results of the impact force/column top displacement time history curves of the specimens in three different damage states under a horizontal impact. The experimental and simulated force time history curves generally agree well with a similar peak impact force and impact duration. The main error is that the plateau impact forces of some specimens (e.g., DZ120-1 and DZ120-3) from the numerical simulation are smaller than those from the test, the reason for which is explained as follows. Due to the presence of damping in the test, it took a relatively long time for the test truck and the specimen to exchange their velocities when they impacted for the first time. In comparison, the damping effect is not considered in the numerical model. As a result, after the impactor contacted the specimen, the specimen instantaneously acquires a higher velocity than the impactor and moves forward and even separates from the impactor. At this time, the impact force rapidly reaches its peak and then quickly drops to zero. Subsequently, the instantaneous kinetic energy acquired by the specimen is partially converted into internal energy, causing the velocity of the specimen to decrease, and the impactor thus catches up with the specimen and another impact occurs. Therefore, within 0-10 ms, the impact force time history curve obtained from numerical simulation has multiple single peaks, which dissipate the initial kinetic energy of the impactor, resulting in a slight deviation in the plateau value of the stable stage of the impact force time history curve obtained from the numerical simulation. Figure 8: Comparison of the damage status under static load (experimental versus numerical). Figure 10: Comparison of the damage status under impact load (experimental versus numerical). Figure 9: Comparison of the load-displacement curve under static load (experimental versus numerical). The column top displacement time history curves obtained from the numerical simulation and the test are consistent, with the error of the maximum displacement at the impact point ranging from 2.56% to 11.03% for the 3 sets of specimens. All the specimens have small errors, with the exception of specimen DZ150-4, which has an error greater than 10% in its simulated peak displacement relative to the experimental value. A possible reason for this relatively large error is that due to the dispersion, the dynamic strengths adopted in the FE simulation considering the strain rate effect possibly differ from the actual strengths, resulting in a slightly larger error than that of the other two specimens. It is worth mentioning that the residual deformation of the specimens obtained from the numerical simulation is larger because, to save on computation time, the termination time for the FE analysis is set short. As a result, the calculation is terminated before the prestressing bars pull the specimen back. Therefore, the deformation recovered in the numerical simulation is essentially caused by the elastic recovery ability of the specimen itself, while there is little rebound effect due to the contraction and stretching of the prestressing bars.