EVALUATION OF ACTING FORCE TO WATER-PIPE BRIDGE BEHIND ROADWAY BRIDGE UNDER TSUNAMI INUNDATION

Abstract

 This study focuses on the damage mechanism of the Yanoura water-pipe bridge behind roadway bridge during the tsunami in 2011. The superstructure of the water-pipe bridge was flooded away due to breakage of side-block bolts at river-upstream side. Acting force to the side-block bolt of bearing under tsunami inundation is modeled as formulation in this study. The rotation of superstructure and damage to sideblock bolt are evaluated by the ratio of acting force to resistance force using result of the tsunami numerical simulation by Naota et al. As the evaluation result, the rotational moment of superstructure contributes the damage of side-block bolt. When the superstructure is not completely covered with the tsunami wave, the superstructure rotates downstream of river as the actual flooded superstructure did. As the interval of two bridges becomes narrow, the wave force to the water-pipe increase and the side-block bolt becomes more likely to have damage.