Management Strategies and Resilience Against NaTech Events

Chapter 6- Seismic Fragility Assessment of an Industrial Plant Substructure and Metastructures for Vibration Mitigation Oreste S. Bursi The tremendous impact of natural hazards, such as earthquakes, tsunamis, flooding, etc., which triggered technological accidents, referred to as natural- technological (NaTech) events, was demonstrated by several recent events as: (i) the Tohoku earthquake and the following Fukushima disaster in 2011; (ii) the Italian earthquakes in 2012 and 2016 which resulted in e42bn between direct and indirect costs, with casualties, thousands of displaced families, and affected business interrup- tion that faced financial problems due non-existent or inadequate insurance. In addi- tion to structural integrity, fitness for service of special risk industrial plants requires an understanding of specific threats, e.g. unrealistic design assumptions, insufficient controls at the construction stage, unexpected/unintended vibrations due to moving loads, etc. Therefore, measures to ensure safe operations depend on hazards and their relationships to the overall condition of the industrial plant. In this context, it is neces- sary to implement and support the Seveso-III Directive 2012/18/EU which regulates the control of major accident hazards involving dangerous substances and to extend the life and to ensure fitness for service of current special risk plants. To tackle this challenge the research conducted by the author and his coworkers involves a com- putational framework for an efficient and accurate seismic state-dependent fragility analysis. It is based on a combination of data acquired from an extensive exper- imental shake table test campaign on a full-scale prototype industrial steel frame structure and the most recent surrogate-based uncertainty quantification (UQ) for- ward analysis advancements. Specifically, the framework is applied to a real-world application consisting of seismic shake table tests of a representative industrial mul- tistorey frame structure equipped with complex process components, carried out at the EUCENTRE facility in Italy, within the European SPIF project: Seismic Perfor- mance of Multi-component Systems in Special Risk Industrial Facilities. The results of this experimental research campaign also aspire to improve the understanding of these complex systems and to improve the knowledge on FE modelling tech- niques. One goal aims to reduce the huge computational burden and to assess, as well, state-dependent fragility curves. Also innovative metamaterial-based solutions for disaster reduction in special risk facilities are proposed. To achieve this scope, the research builds upon the most recent innovative scientific and technological concepts developed within the research field of locally resonant phononic metamaterials. In particular, the feasibility of such metamaterial-based isolation concepts and systems is demonstrated across different low-frequency ranges, e.g. seismic waves. These general developments have further advanced through novel isolation concepts which can achieve negative effective mass and stiffness moduli in structures and through nonlinear mechanisms such as bistability. In sum, this research intends to conceive metastructures capable of rendering industrial plant equipment fully or partially isolated from the effects of incident waves impinging from all directions.