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.
