If　a　bridge　is　subjected　to　a　blast　load　when　there　is　vehicle　traffic,　not　only　its　own　safety　is　threatened,　but　it　can　also　lead　to　damage　to　vehicles.　In　addition,　the　coupling　of　a　vehicle　load　and　an　explosion　load　may　further　aggravate　the　impact　of　an　explosion.　To　understand　the　coupling　relationship　between　the　two　kinds　of　loads　on　a　bridge,　a　static　load　was　applied　on　the　bridge　using　the　impact　coefficient　while　a　blast　load　was　applied　on　the　outside　of　the　bridge.　A　numerical　simulation　was　also　used　to　further　study　the　coupling　effect　of　the　vehicle　load　and　the　explosion　load.　The　results　showed　that　the　vehicle　load　could　effectively　limit　the　vertical　deformation.　The　numerical　model　was　accurate　in　predicting　the　response　process　of　the　stiffened　beam.　With　the　coupling　of　the　vehicle　load,　the　equivalent　plastic　strain　of　the　box　multistage　stiffened　beam　was　mainly　concentrated　at　the　hinge　and　decreased　when　the　blast　loading　remained　constant.　The　transverse　anti-blast　performance　of　the　stiffened　beam　was　mainly　provided　by　the　bridge　web　and　the　diaphragm　under　the　coupling　effect　of　the　vehicle　load　and　the　blasting　load,　but　the　function　of　the　diaphragm　was　weakened.　Additionally,　the　hinge　used　as　a　connector　was　able　to　directly　affect　the　bearing　capacity　of　the　bridge.　Even　if　the　hinge　was　only　slightly　damaged,　it　could　cause　the　bridge　to　enter　the　failure　stage,　meaning　that　the　strength　of　the　hinge　must　be　greater　than　that　of　the　bridge.