Dynamic behavior and damage assessment of RC columns subjected to lateral soft impact

In this study, the performance and damage behavior of reinforced concrete (RC) columns under lateral soft impact are comprehensively investigated using 3D finite element (FE) analysis. Firstly, refined FE models of RC columns are developed in LS-DYNA, and the corresponding simulation techniques are verified against existing experimental testing data. Then, response characteristics of a typical column under soft impact are examined, and a section damage factor is defined to quantify the damage evolution of impacted columns. After that, the effects of various design parameters, including impactor stiffness, impact elevation, axial force ratio, section dimension, and combination of impact mass and velocity, on the dynamic behavior of columns are examined. Finally, criteria for both flexural damage and shear damage are proposed based on the section damage factor, and the resistance dynamic increase factor (RDIF) of RC columns under soft impact is utilized to establish a rapid damage assessment methodology. From these results, it is proved that the dynamic responses and failure modes of RC columns under soft impact are quite different from those under hard impact. The impactor stiffness and impact elevation have a significant effect on the mechanical mechanism of columns, and the column resistance generally increases with the axial force to a certain extent. In addition, RDIF of columns decreases with the increase in the ratio of the impact time at peak force t(p) to the column natural period T-col.