Experimental and theoretical investigation on axial compressed concrete-filled double-skin steel tubes with local corrosion under lateral impact loading

This study employed experimental and theoretical approaches to examine the lateral impact response of axially loaded concrete-filled double-skin steel tubular (CFDST) members with local corrosion. Experimental tests were carried out to systematically investigate the influences of the corrosion area, corrosion depth ratio, and axial compression ratio on the failure mechanisms and impact response of the corroded CFDST members. The results indicated that more severe corrosion would significantly weaken the structural impact resistance, characterized by decreased impact force and increased displacements. A higher axial compression ratio was also found to reduce the impact resistance of the corroded CFDST member. A global bending deformation was observed for the corroded CFDST member, together with the presence of slight local indentation. Furthermore, a theoretical model based on a two-degree-of-freedom (TDOF) system was developed to calculate the time histories of impact force and displacement for the corroded CFDST members. The predicted results showed good agreement with the experimental data, verifying the accuracy and reliability of the proposed model for assessing the impact responses of corroded CFDST members.