From a Probabilistic PBEE Framework to Risk-Targeted Structural Design With Cascading Hazards: Engineering Application for Seismic–Radiological Safety

Abstract

Earthquake-induced damage of structures can trigger cascading hazards, linking structural performance to nonstructural consequences. In current engineering practice, these two aspects are typically addressed separately, limiting the ability to account for such coupled effects in design. A typical example arises in nuclear and radiological facilities, where earthquake-induced structural damage may compromise containment functions and lead to radiological consequences. This study presents an engineering application of an introduced probabilistic performance-based earthquake engineering (PBEE) framework that accounts for radiological hazards arising from earthquake-induced cracking of reinforced concrete barriers. The PBEE framework is simplified into a risk-targeted verification procedure and implemented as a seven-step design methodology. The interaction between seismic effects and radiological consequences is addressed by introducing a permeability-based limit state, which directly links radiological studies to the risk-targeted seismic design. This limit state serves as a single performance measure, capturing the effect of seismic cracking on barrier permeability and providing a physically meaningful link between structural damage and potential radioactive release. The methodology was applied to the design of a near-surface repository for low- and intermediate-level radioactive waste in Slovenia, highlighting interdisciplinary challenges and the need for iterative refinement of structural reinforcement and radiological analyses, eventually conducted by engineering practitioners. The procedure extends current engineering practice, but it relies on simplifying assumptions of the PBEE framework. Its robustness should be further explored through sensitivity studies on fragility dispersion, damage—permeability relationships, and cascading hazard modelling. Beyond radiological applications, the framework provides a general pathway for incorporating cascading hazards into risk-targeted, performance-based seismic design.