Continuous twice-impact analysis of steel parking structure columns

In this study, two impact tests are performed on a one-fifth scaled parking structure to obtain their columns' failure modes and response. A numerical model is developed to simulate the experiment, which considers the effects of the damage evolution and material fracture. Additionally, serial numerical analyses of the two impacts with constant total energy are conducted based on the validated model. The influence of the energy allocation between the two impacts on the impact force, residual displacement, and residual kinetic energy are investigated. An assessment method is proposed for the damaged column. The results show that the shape change and material hardening are the main reasons that affect the impact resistance of the damaged column. When the column is damaged, its robustness against the second impact is improved. With a constant total energy, the damage degree of the column caused by the single impact is larger than that of the two impacts. The effect of energy allocation on the residual displacement is 4.6% to 8.6% in the numerical calculations. The proposed assessment method can serve as a basis for future evaluation of the damaged column.