This study investigates the structural redundancy of arch steel aqueduct bridges in response to the collapse of the Musota Aqueduct Bridge located in Wakayama City due to corrosion of hanging members. The bridge comprises a seven-span steel arch bridge constructed in 1973. Through a meticulous examination of this case study, we assess the bridge’s ability to sustain loads following the potential failure of hanging members due to corrosion. The assessment employs static non-linear structural analysis, a standard procedure for evaluating redundancy. A three-dimensional finite-element (FE) model is developed to accurately simulate the bridge’s properties. Additionally, a comprehensive static nonlinear finite element analysis focusing on the hanging members of the arch bridge elucidates the consequences of potential failure on redundancy. Based on the investigation’s findings, recommendations for prudent bridge maintenance practices are proposed, aiming to ensure the longevity and safety of similar bridge structures.