Damage assessment method of RC piers under lateral impact loads

To investigate the dynamic response and damage assessment of reinforced concrete (RC) piers under lateral impact loads, high-fidelity finite element models of RC piers under lateral impact were developed using the explicit dynamic analysis software LS-DYNA. The finite element models were calibrated by using the test data from lateral impact tests of RC piers. The influences of impact velocity, impact mass, impact location, and axial compression ratio on the dynamic response and damage evolution of RC piers were investigated. Based on the residual load-carrying capacity and residual displacement, the indicators of relative residual deformation and relative residual load-carrying capacity were proposed. The corresponding values of relative residual load-carrying capacity for slight damage, moderate damage, severe damage, and collapse were determined. Moreover, a mapping relationship between relative residual deformation and relative residual load-carrying capacity of RC piers with various axial compression ratios and impacted at different impact locations was established. A damage assessment method for RC piers under impact load was proposed based on the mapping relationship. The research results indicate that RC piers subjected to impact at the mid-column position primarily exhibit flexural-shear failure, whereas local shear failure predominantly occurs when the impact is applied close to the column base. As the impact velocity and mass increase, the residual displacement increases significantly, while the residual bearing capacity decreases. The axial compression ratio within the range from 0.2 to 0.4 has a limited effect on the peak impact force and peak displacement but significantly affects the residual displacement when the impact occurs at the mid-column. When the mid-column position and the column base position are subjected to lateral impact, there exists an approximate linear relationship between relative residual deformation and relative residual load-carrying capacity, such that the greater the relative residual deformation, the smaller the relative residual load-carrying capacity. Under conditions of equal relative residual deformation, the relative residual load-carrying capacity of the base-column impact is lower than that of the mid-column impact, with a more significant decrease in load-carrying capacity.