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.
