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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. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations on circular concrete‐filled double steel tubular (CFDST) members under flexural load. Seven specimens including five CFDST specimens were tested and the test parameters included the effects of concrete compressive strength, the thickness of the steel tubes, and the diameter ratio on their flexural performance. The final failure modes, moment (M)‐curvature (ϕ) curves, deflection curves of specimens, and distributions of section longitudinal strains were analyzed and reported in this study. A nonlinear finite element model (FEM) was then developed for the CFDST members. After successful validation in ultimate strengths and failure modes, parametric studies were performed by using the verified FEM. A simple formula for calculating the flexural capacity of CFDST members was proposed and compared against several design codes to investigate the design accuracy. Based on this study, it was found that the CFDST members exhibit ductile behavior under flexural load. Increasing the steel area, particularly for the outer tube improved the flexural capacities of the members. Furthermore, the existing design codes were found to be remarkably underestimating the moment capacities of CFDST members whereas the design formula proposed can predict the ultimate flexural capacity with reasonable accuracy. [ABSTRACT FROM AUTHOR]