Experiments on the tsunami force and pressure acting on oil tanks. The tsunami concerned in the present paper is that is expected to be generated by future Tokai and Tonankai earthquakes. The maximum water level of about 5 m is estimated at a certain power plant site. Two types of experiment were carried out: Measurements of the tsunami force acting on a single tank as a fundamental test and these on tanks in a tank complex as a practical problem. The effect of the free surface on the drag coefficient was discussed. If the tanks of which diameter ranges from 5.8 m to 48.6 m and weight ranges from 5.8 t to 540 t are empty, they can be floated due to in case of 2-m-high flooding. The tsunami pressure acting on tanks surrounded by oil protection walls is not uniform and the buckling of the side wall is very sensitive to the distribution of pressure around the tank. The lowest level of oil in the tank should be kept higher than the estimated inundation depth to prevent the tanks from floating and buckling.

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