Experimental and numerical investigation on seismic performance of corroded box-section steel columns

Nine box-section steel columns were subjected to accelerated corrosion and quasi-static testing to investigate their seismic performance. The failure modes, load-bearing capacity, and energy dissipation capacity of the corroded box-section steel columns were analyzed and compared to evaluate the effects of corrosion level, axial load ratio, and width-to-thickness ratio on hysteretic behavior. A parametric study was conducted using the validated FE model to obtain hysteresis data for corroded box-section columns across a wider range of parameters, aiming to quantify the degradation laws of the residual ultimate bearing capacity of corroded columns. Subsequently, a predictive model was developed to estimate the residual bearing capacity of the corroded columns. The results indicated that the failure mode in all specimens was local buckling at the column base. The earlier onset of local buckling led to significant reductions in the load-bearing capacity, plastic deformation capacity, and energy dissipation capacity of the corroded columns. Furthermore, the axial load ratio and width-to-thickness ratio were identified as critical parameters influencing the seismic performance of box-section columns. When excessive axial load or an increased width-to-thickness ratio was combined with corrosion damage, the seismic performance of the box-section columns was substantially compromised. The residual bearing capacity prediction model, developed through nonlinear regression analysis of the parametric study data, demonstrated high accuracy in predicting the bearing capacity of corroded box-section steel columns.