Optimal intervention policy of bridges considering earthquake occurrence probability increasing over time

In recent years, the possibility that damage of infrastructure at the time of earthquake could change depend-ing on their deterioration conditions has been noted by analytical calculations, mechanistic simulations,etc.Also,itisgenerallysaidthatoccurrenceprobabilitiesoftheinter-plateearthquakesareincreasing over time. They imply that i) intervention policies of infrastructure need to be determined internalizing risk of earthquake, and ii) an optimal intervention policy would change over time as the earthquake occurrence probability increases. In this study, targeting a bridge element whose deterioration process is modeled as a Markov process, the optimal intervention policy is calculated to minimize its life cycle cost considering risks of both deterioration and earthquake, supposing damage of the bridge element by earthquake varies depending on its condition state. Then, under the situation where the earthquake occurrence probability is increasing over time supposing an actual earthquake, it is investigated how the optimal intervention policy of the bridge element would change over time.