Quantitative seismic risk analysis of storage facilities in seismic areas

Quantitativeriskanalysis(QRA)ofindustrialfacilitieshastotakeintoaccountmultiplehazardsthreateningcriticalequipment.Nevertheless,engineeringproceduresabletoevaluatequantitativelytheeffectofseismicactionarenotwellestablished.Indeed,relevantindustrialaccidentsmay be triggered by loss of containment following ground shaking or other relevant natural hazards, either directly or through cascade effects(‘domino effects’).The issue of integrating structural seismic risk into quantitative probabilistic seismic risk analysis (QpsRA) is addressed in this paperby a representative study case regarding an oil storage plant with a number of atmospheric steel tanks containing flammable substances.Empirical seismic fragility curves and probit functions, properly defined both for building-like and non building-like industrial components,have been crossed with outcomes of probabilistic seismic hazard analysis (PSHA) for a test site located in south Italy. Once the seismicfailure probabilities have been quantified, consequence analysis has been performed for those events which may be triggered by the loss of containment following seismic action. Results are combined by means of a specific developed code in terms of local risk contour plots, i.e. thecontourlinefortheprobabilityoffatalinjuresatanypoint( x , y )intheanalysedarea.Finally,acomparisonwithQRAobtainedbyconsideringonly process-related top events is reported for reference.