Tatsuo Sasaki

Analysis of Tsunami Damage of Kesen Bridge in Rikuzentakata Area

Many bridges in the coast of Rikuzentakata Area were destructed by the tsunami due to Great East Japan Earthquake. From field surveys, it was confirmed that many bridge girders were swept away and a variety of videos recording tsunami were obtained. In this research, the video analysis and two-dimensional numerical analysis based on the non-linear long wave theory were conducted. Moreover, it was observed that the Kesen Bridge was not affected by bore wave at surge front, but was washed away by the steady flow with the velocity of about 6.0m/s.

Evaluation of Bore Wave Horizontal Force on Bridge Girder with Use of Pressure Gauges

In order to find out the mechanism of tsunami bore wave on bridge girder, the bore wave experiment was carried out with a bridge girder model. As a result, the measured maximum horizontal force on bridge girder by force transducer was found close to the calculated maximum force by the integration from the wave pressures on girder front surface. Thus, the horizontal force is dominant to the wave pressure on girder front surface. Besides, from the parameter study of wave height, it is noted that both horizontal force and the wave velocity of girder location are proportional to wave height. Thus, it is concluded that bore wave horizontal force has a high correlation with wave height.