Analytical Investigation of Support Condition Effect on Load-Bearing Performance of Corroded Steel Girder Ends

This study investigated the effect of corrosion damage on the load-bearing capacity of steel girder ends under varying support conditions. A detailed finite element analysis was conducted using ABAQUS to simulate corrosion at the girder ends, considering different combinations of thickness reductions in the web and vertical stiffeners based on actual damage patterns observed in bridges. Two support conditions, i.e. healthy (rotationally free) and unhealthy (rotation constrained due to deterioration), were modeled to reflect realistic bridge aging scenarios. Corrosion was assumed to occur below the crossbeam near the sole plate, and 72 different corrosion cases were analyzed. Additionally, it was assumed that when corrosion occurs, the result is uniform thinning of the affected members and that corrosion at the support is spread over the sole plate surface. The results indicated that under healthy support conditions, the load is evenly distributed among components, and the capacity is proportional to the remaining effective cross-sectional area of the web and vertical stiffener. In contrast, under unhealthy support conditions, the load is concentrated on the web on the span side, making the location of corrosion critical. The findings emphasize the importance of considering both the extent of corrosion and the support conditions when evaluating the structural performance of aging steel girder bridges.