Performance based earthquake assessment of an industrial gas filter structure

Industrial facilities often store a large amount of hazardous material and, in case of seismic event, there is a high probability that accidental scenarios as fire, explosion, toxic or radioactive dispersion may occur. Moreover, the structural configuration of industrial facilities are often the fruit of plants and functionality requirements, that lead to strong irregularities and different load resisting systems within the same structure. This paper presents a performance-based earthquake assessment of an industrial gas filter structure, characterized by the presence of important masses placed at significant height and of different horizontal resisting systems, such as moment resisting frames, inverted V bracings and diagonal bracings. Within the framework of the PROINDUSTRY research project critical failure mechanisms of industrial structures and relevant limit states are analyzed and discussed. The structural response is computed via nonlinear finite elements analyses of the static pushover (PO) and dynamic response history type (RHA). The seismic input is defined through Probabilistic Seismic Hazard Analysis (PSHA) and a set of natural Ground Motions (GM) which are selected and scaled with different criteria with respect to the Uniform Hazard Spectrum (UHS) and the Conditional Mean Spectrum (CMS). An overview of significant aspects of the structural performance assessment is presented with respect to input definition and choice of Intensity Measures (IM), irregular structural behaviour and probabilistic treatment of key Engineering Demand Parameters (EDP) for this type of industrial structure.