The　possibility　of　blast　impact　loads　acting　on　bridge　structures　is　gradually　increasing.　The　local　and　entire　explosion　response　law　of　a　concrete　box　girder　bridge　is　still　unclear,　and　anti-explode　devices　for　reducing　the　entire　explosion　response　of　a　bridge　are　scarce.　In　this　study,　a　rotational　inertia　particle　damper　(R-IPD)　and　a　1:4　scale　model　of　a　typical　three-span　continuous-girder　bridge　were　designed　and　manufactured.　Subsequently,　an　explosion　test　of　the　bridge　model　with　and　without　R-IPDs　was　conducted.　The　results　showed　that　the　local　dynamic　response　(LDR)　of　the　bridge　model　was　more　likely　to　occur　under　an　explosion　load.　The　local　overpressure,　strain,　and　acceleration　responses　of　the　box　girder　near　the　explosion　centre　were　more　significant　than　those　at　other　locations　or　of　other　components.　Moreover,　the　LDR　of　the　box　girder　was　similar　in　the　middle　and　side　spans.　As　the　explosive　equivalent　(EE)　increased,　the　entire　displacement　response　(EDR)　of　the　model　bridge　increased.　Under　the　same　EE　conditions,　a　larger　span　suffered　a　larger　EDR.　After　the　R-IPD　installation,　the　EDR　of　the　bridge　model　decreased.　Furthermore,　the　damping　effect　of　the　R-IPDs　on　the　EDR　of　the　bridge　model　increased　with　an　increase　in　the　EE,　and　the　maximum　vibration　reduction　rate　was　up　to　12%.　However,　the　damping　effect　of　the　R-IPDs　on　the　LDR　of　the　model　bridge　was　not　obvious.　The　damping　effect　of　the　R-IPDs　depended　on　the　relative　displacement　between　the　two　ends　of　the　damper　and　exhibited　obvious　hysteresis.