CLARIFICATION OF TSUNAMI WAVEFORMS ACTING ON A BRIDGE STRUCTURE SUBJECTED TO THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE TSUNAMI

Abstract

 The features of tsunami waveforms acting on a bridge subjected to the 2011 off the Pacific Coast of Tohoku earthquake tsunami are clarified. The waveforms are classified into 5 types from view of points of the increasing rate of inundation depth and inclination of wavefront. For 74% of bridges, the increasing rate of inundation depth is less than 2.0 m/min. The relationship between the increasing rate of inundation depth and the slope angles of sea and land areas around a bridge are revealed. The tsunami waveforms with the increasing rate of inundation depth of more than 5.0 m/min require the slope angles of more than 0.01 rad of sea areas and more than 0.05 rad of land areas. Finally, the dependence of the shape of wavefront on the increasing rate of inundation depth is clarified.