Probabilistic seismic analysis (PSA) is a methodical approach to assessing earthquake risk for buildings or technical systems. It combines the characterization of seismic hazard, the analysis of structural response, and the estimation of damage probability to obtain a comprehensive picture of the risks.
 

The PSA consists of three main components:

• Hazard analysis – determining the probability of occurrence and intensity of earthquakes at the site,

• Fragility analysis – calculating the probability of failure of structures or components depending on seismic stress,

• Impact analysis – assessing the impact of a failure on safety, functionality, or economic damage.

Fragility analysis forms the central link between seismic stress and structural behavior. Nonlinear dynamic analyses are performed to determine engineering demand parameters (EDPs) such as interstory drift or accelerations in storeys. Based on these results, fragility curves are created that describe the probability with which a certain damage state will be exceeded at a given earthquake intensity.

Traditional methods are usually based on parametric assumptions (e.g., lognormally distributed fragility functions) and regression techniques, which, however, often have limited ability to represent complex structural responses or uncertainties. Newer, nonparametric methods offer more accurate results but require significantly greater computational effort. Further development of fragility analysis is crucial, especially for safety-relevant infrastructures such as nuclear power plants, hospitals, or industrial facilities.

 

Project reference:

• METIS (2020-2025) : https://metis-h2020.eu/
  This research is being conducted as part of METIS, a Horizon 2020 project funded by the Euratom Research and Training Program (September 2020–May 2025). METIS brings together 16 partners from 9 countries and aims to advance the seismic risk analysis of nuclear power plants by improving the modeling of hazard, vulnerability, and consequences within the framework of probabilistic safety assessment (PSA).

• SMA-PSA (2023-2026):
  SMA-PSA is a research project that deals with the fundamentals of seismic margin assessments and probabilistic safety analyses (PSA) for nuclear structures. The aim of the project is to develop improved methods and tools for assessing and increasing the seismic resistance of nuclear facilities by integrating advanced seismic margin analysis techniques into the PSA framework.