Blast-Resistant Performance Evaluation of Steel Box Girder of Suspension Bridge

Explosions pose significant risks to large-span steel bridges, which are integral to modern transportation networks and construction projects. This study evaluates the blast resistance of the orthotropic bridge deck of the Taizhou Yangtze River Bridge using numerical simulations validated by explosion tests. Five vehicular bomb scenarios, as specified by the Federal Emergency Management Agency, were analyzed to understand the damage mechanisms under above-deck explosions. Results show that all scenarios cause petal-shaped openings in the top plate, fractures in U-stiffeners, and plastic deformation in diaphragms. Larger TNT masses lead to additional failures, such as outward bending and bottom plate openings. Energy dissipation primarily occurs through plastic deformation and failure of various deck components, with the extent depending on the TNT mass. The vehicle shell significantly reduces damage for smaller charges (454 kg TNT) but has a minor effect for larger charges (>4536 kg TNT). This research enhances the understanding of blast resistance in orthotropic steel decks, a key component in modern bridge construction, and informs practices for designing resilient structures.