Reliability of bridges under tsunami hazards: Emphasis on the 2011 Tohoku-oki earthquake

The probabilistic estimation of tsunami impact on bridges and the evaluation of potential tsunami risk are important topics, but they are still in very early stages of development. First, this paper presents the damage of bridges during the great Tohoku-oki earthquake and giant tsunami of 11 March 2011 based on the field damage investigation. The damage conditions and the possible failure mechanisms of bridges due to tsunami are particularly discussed. Second, tsunami fragility curves are presented. Empirical tsunami fragility curves based on the utilization of damage data associated with past tsunami disasters have been developed. In this paper, the tsunami fragility curves are established based on simulations. Bridge failure probability can be estimated using the tsunami hazard and fragility curves. Finally, an illustrative example of the reliability estimation of a bridge exposed to tsunami hazard is presented.