Application of a Modified Estimation Formula for Collision Force of Deformed Drifting Containers under Tsunami Conditions

초록

Damage from a tsunami can be divided widely into direct damage and indirect damage by drifting bodies owing to a run-up wave. Indirect damage attributable to freight containers, which play a major role in international trade, is a concern owing to the effect on international and domestic economic activities. Recently, Japan incurred tremendous damage from a tsunami that occurred after the 2011 Great East Japan Earthquake and recorded the greatest amount of economical loss and highest wave run up (40 m in the Ryori district of Ofunato City) historically (PIANO Marcom WG53, 2010). A previous study proposed an estimation formula for a collision force of a container at drift from a run-up tsunami, which comprises the impulse and momentum of the container and the added mass. In this study, a modification of the existing estimation formula for the collision force of a drifting container from a run-up tsunami was implemented, and its improvement was verified through a comparison between laboratory and numerical experiments. Additionally, the estimation formula was revised for application to a large deformed container, and its applicability under prototypical conditions was confirmed through a comparison with the verified numerical model. Finally, for practical use, a simplification of the estimation formula was applied. As a result, the simplified version of the estimation formula, which considers a large deformation, was shown to have a similar form as the original estimation formula, which did not consider a large deformation, although the influence of the added mass has decreased.

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