Post-Fire Assessment and Rehabilitation of the Ulsan Suspension Bridge

In September 2019, a fire beneath the Ulsan Suspension Bridge exposed sections of its steel box girder and suspension system to intense heat. Prompt emergency inspections supported by structural health monitoring (SHM) confirmed that the primary load-carrying components remained intact, allowing the bridge to reopen within 27 h. A comprehensive post-fire assessment was subsequently conducted, combining on-site inspections (including drone surveys for inaccessible areas), thermal analysis, and protective-coating evaluations, together with geometry checks and monitoring-data review. The investigation indicated that the main structural system was unaffected, and that damage was confined to coatings and ancillary components such as communication cables and the dehumidification system. Based on these findings, a targeted rehabilitation programme was implemented to restore the affected elements. Continuous SHM of the bridge’s static and dynamic behaviour over several years has shown no abnormal trends, confirming the bridge’s post-fire integrity and the effectiveness of the rehabilitation measures.