Release of Hazardous Substance Due to Seismic Loads: Influence of Pipe to Tank Connection in Fragility Estimation

The damage observed during past earthquakes demonstrated the need for the seismic vulnerability assessment of industrial plants to reduce the risk of major accidents and to develop detailing for risk mitigation. If damaged by a seismic event, industrial plants might be affected by a domino effect with the consequent interruption of plant serviceability and severe economic losses; at the same time, toxic substances could be released due to the damage of pipelines and tanks, causing environmental damages and loss of lives. This preliminary study investigates the influence of the dynamic properties of pressurised tanks on the industrial plant seismic vulnerability, focusing on the possible issues to which the pipelines connecting the tanks are prone. To this purpose, numerical analyses are conducted aimed at identifying the most critical conditions in terms of displacements and stress state to which the pipelines are subjected. At the same time, a framework for the definition of fragility functions including the damage states related to piping connections, is also presented.