Abstract
This study proposes a certain measure for decision making associated with the seismic retrofitting investment strategy preventing a large-scale malfunction such as water supply loss under seismic risks. Newly developed stochastic value index is adopted for the overall evaluation of social benefit, income, life cycle costs and failure compensation associated with the existing lifeline systems damaged by an earthquake during the remaining service period. Discussions are given for the optimal seismic disaster prevention investment of the existing deteriorated lifeline system. Finally, the present study can provide a performance-based design method for seismic retrofit strategies of existing lifelines which can be carried out through the target probabilities of value loss and structural failure.
