PSI - Issue 78

Alessio Bonelli et al. / Procedia Structural Integrity 78 (2026) 505–512

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5. Conclusions The aim of this work is to raise awareness, both within the scientific community and among industry stakeholders, of the critical issue of the seismic sliding behavior of these facilities. While the scenario does not represent a substantial threat when the connected pipelines are aboveground (as reduced relative displacements occur due to the system's good intrinsic ductility), the situation becomes more critical when underground pipelines are connected to unanchored tanks. Although underground piping systems are being progressively phased out due to environmental and pollution control regulations, numerous existing installations still use this configuration. In these cases, it is essential to account for sliding-induced fragility in terms of leakage. Additionally, this study marks the beginning of a broader research effort aimed at investigating the leakage mechanisms of tanks through their connected piping systems. Future work will involve developing simplified numerical models that incorporate the uplifting mechanism and validating them through laboratory testing and advanced nonlinear numerical simulations focused on the seismic response of unanchored steel storage tanks. References 1998-4, E. (2006). Eurocode 8 - Design of structures for earthquake resistance - Part 4: Silos, tanks and pipelines. Eurocode 8: Desing of Structures for Earthquake Resistance , 4 (2006). Antonioni, G., Spadoni, G., & Cozzani, V. (2007). A methodology for the quantitative risk assessment of major accidents triggered by seismic events. Journal of Hazardous Materials , 147 (1–2). https://doi.org/10.1016/j.jhazmat.2006.12.043 Bursi, O. S., Reza, M. S., & Kumar, A. (2012). Seismic Performance of Bolted Flange Joints in Piping Systems for Oil and Gas Industries. 15th World Conference on Earthquake Engineering, Lisbon Portugal , 8 . Cotton, F., Iervolino, I., Pitilakis, K., Stojadinović, B., & Zwicky, P. (2016). Harmonized approach to stress tests for crit ical infrastructures against natural hazards. In 6th World Conference on Earthquake, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017 . Housner, G. W. (1957). Dynamic pressures on accelerated fluid containers. Bulletin of the Seismological Society of America , 47 (1). https://doi.org/10.1785/bssa0470010015 Kalemi, B., Farhan, M., & Corritore, D. (2019). Sliding response of unanchored steel storage tanks subjected to seismic loading. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP , 8 . https://doi.org/10.1115/PVP2019-93310 Karamanos, S. A., Giakoumatos, E., & Gresnigt, A. M. (2003). Nonlinear Response and Failure of Steel Elbows Under in-Plane Bending and Pressure. Journal of Pressure Vessel Technology, Transactions of the ASME , 125 (4). https://doi.org/10.1115/1.1613949 La Salandra, V., Di Filippo, R., Bursi, O. S., Paolacci, F., & Alessandri, S. (2016). Cyclic response of enhanced bolted flange joints for piping systems. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP , 8 . https://doi.org/10.1115/PVP2016-63244 Malhotra, P. K., Wenk, T., & Wieland, M. (2000). Simple procedure for seismic analysis of liquid-storage tanks. Structural Engineering International: Journal of the International Association for Bridge and Structural Engineering (IABSE) , 10 (3). https://doi.org/10.2749/101686600780481509 Paolacci, F., Corritore, D., Caputo, A. C., Bursi, O. S., & Kalemi, B. (2018). A probabilistic approach for the assessment of LOC events in steel storage tanks under seismic loading. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP , 8 . https://doi.org/10.1115/PVP2018-84374 Phan, H. N., Paolacci, F., Nguyen, V. M., & Hoang, P. H. (2021). Ground motion intensity measures for seismic vulnerability assessment of steel storage tanks with unanchored support conditions. Journal of Pressure Vessel Technology, Transactions of the ASME , 143 (6). https://doi.org/10.1115/1.4051244 Salimbeni, M., De Angelis, M., & Ciucci, M. (2023). Analysis of the Behaviour of the Floating Roof in a Cylindrical Storage Tank Subjected to Seismic Excitation for the Mitigation of Fire Risk. Chemical Engineering Transactions , 104 . https://doi.org/10.3303/CET23104019 Vathi, M., & Karamanos, S. A. (2015). Simplified model for the seismic performance of unanchored liquid storage tanks. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP , 5 . https://doi.org/10.1115/PVP2015-45695 Wieschollek, M., Hoffmeister, B., & Feldmann, M. (2013). Experimental and numerical investigations on nozzle reinforcements. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP , 8 . https://doi.org/10.1115/PVP2013-97430