PSI - Issue 44

Mariano Ciucci et al. / Procedia Structural Integrity 44 (2023) 347–354 Mariano Ciucci, Valerio Vezzari, Alessandra Marino / Structural Integrity Procedia 00 (2022) 000–000

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some improvements. The seismic vulnerability of process plant components can be investigated using different tools. Because risk and resilience analysis often requires a probabilistic approach, fragility curves need to be employed, which represents the probability of exceeding a given limit state. Fragility curves can be derived using approaches of increasing complexity as judgmental, empirical (or observational) and numerical. A reference document for fragility and risk analysis is the well-known HAZUS manual which provided, for most of the structural and nonstructural constructions, including oil & gas installations, proper fragility curves. Fig. 1 shows a collection of this fragility curves for the above-mentioned structural categories in terms of extensive damage (HAZUS 2001). It easily recognizable the highest vulnerability of the columns as well as of vertical and horizontal storage tanks. Less problematic are the piping systems and the stacks. Consequently, it is clear the necessity to adopt mitigation measures. In this respect passive and active strategies could be adopted. In this paper the use of active solutions that is “Integrated SMART sensors” for the seismic risk management of major-hazard industrial plants, which includes early warning systems and active protection systems as Safety Interlock Systems (SIS) based on different typologies of sensors.

Fig. 1. fragility curves for process plant components.

3. Earthquake Early Warning Systems Early warnings systems are recognized as a focal point for the prevention of nuclear accidents, whereas poor attention has been given to the seismic safety management of chemical process plants, where a large amount of hazardous chemicals is usually stored. On the other hand, providing a reliable warning from few seconds to minute before the ground motion arrives is now possible. The most important component of a regional earthquake early warning system is a dense network of seismic and geodetic stations with robust communications.

Fig. 2. earthquake early warning systems.