Perspectives on probabilistic risk assessment of concrete gravity dams

This study presents guidelines for the implementation and interpretation of fragilities in the decision-making process and risk-management of concrete gravity dams. It illustrates how fragilities are used within the context of a fully coupled probabilistic safety assessment (PSA). Quantitative risk metrics are computed and ranges of the hazards that are the main contributors to risk are identified. Comparison of these metrics indicates whether the risks due to the competing hazards, i.e. the hydrologic and seismic hazards, are balanced. Fragilities and PSA results are compared to socially "acceptable risks" in other human endeavors, which are described briefly in this study. The resulting quantitative risk metrics are indispensable in the decision-making process of the allocation of limited resources to mitigate risk by dam inspection, rehabilitation, or changes in policy.