2024 Volume 80 Issue 13 Article ID: 23-13092
Efficient tsunami countermeasures for bridges at coastal roads along Nankai Trough require a risk assessment of washout of superstructure due to tsunamis. This study uses a probabilistic hazard assessment method combining the random-phase tsunami model and the coRaL method to assess the probability of bridge superstructure washout risk considering the uncertainties in tsunami hazard prediction. The results of the safety assessment of coastal bridges in Wakayama Prefecture by the Nankai Trough megathrust earthquake tsunami show that the risk of bridge washout is increased in 16 bridges concerning the action force/strength ratio compared to the case of the Tokai-Tonankai-Nankai consolidated type earthquake model. The probabilistic tsunami hazard assessment method was used to quantitatively evaluate the washout risk of bridge superstructures by the return period. The effects of the bearing anchors and displacement-limiting structures as countermeasures were expressed by the increase in the critical tsunami height and the return period.
