Abstract
Utatsu Bridge, a prestressed concrete bridge, suffered enormous damage from the destructive tsunami waves triggered by Great East Japan Earthquake, on March 11th, 2011. Based on the field survey, the damage condition and the possible mechanisms of Utatsu Bridge have been summarized. It has been found that the girders G3~G10 suffered serious displacements while all piers did not flow out. By comparing the β value s (ratio between girder resistance and wave horizontal force) with other damaged bridges, it was confirmed that the girders did not have sufficient resistance. On the other hand, the acting moment is less than the yield moment at the base of pier column, therefore the piers did not collapse.
