Assessment on impact response analysis by chord member fracture of steel truss bridge

In this paper, the impact response due to member fracture was evaluated by dynamic 3D FEM analysis using a frame model considering the composite effect of the steel members with the deck. Furthermore, the experimental results and the analysis results of fracturing the members of the existing steel truss bridge were compared. Therefore, it was confirmed that the FEM analysis result of the impact coefficient has an evaluation accuracy within an error of about 10% compared with the experimental result in the practical stress fluctuation range. Furthermore, it was analytically verified that the impact coefficient decreases to about 1.0 when the fracture time from the start to the completion of the member fracture increases to about the natural period. In addition, it was analytically verified that the influence of the load bending moment and the change in deck rigidity on the impact coefficient was small.