Seismic risk assessment of liquid overtopping in a steel storage tank equipped with a single deck floating roof

Caprinozzi, Stefano (author), Paolacci, Fabrizio (author), Dolšek, Matjaž (author)

Major earthquakes have demonstrated that Natech events can be triggered by liquid overtopping in liquid storage tanks equipped with floating roofs. Thus, research on the dynamic behaviour of steel storage tanks with floating roofs is still required. In this paper, the seismic risk against liquid overtopping in a real steel storage tank with a floating roof was analysed using a simplified model that was validated by a refined finite element model based on the arbitrary Lagrangian-Eulerian approach. The simplified model utilizes the Lagrangian of a floating roof-fluid system and is capable of providing a response history of the floating roof. It was demonstrated that it could predict the maximum vertical displacement very accurately, while some differences were observed in the response history of vertical displacement. The computational time for a single response history analysis based on the simplified model amounted to a few minutes, which is significantly less demanding compared to hours required for response history analysis in the case of the refined FE model. The simplified model is thus appro-priate for the seismic fragility analysis considering the overtopping limit state. It is shown that the fragility curves are significantly affected by the liquid filling level. The risk for liquid overtopping is quite high in the case of a full tank. However, by considering the variation of filling level during the year, the overtopping risk was observed reduced by approximately 30%. Alternatively, the approximate fragility analysis for the liquid over-topping can be performed by utilizing the Eurocode formula for the vertical displacement of liquid. This approach is straightforward, but the formula does not account for the higher mode effects, which may result in overestimated seismic intensity causing overtopping, as discussed in the paper

• Language: English
• Keywords: floating roof, steel storage tanks, simplified model, refined model, petrochemical plants, seismic fragility analysis, seismic risk assessment, risk mitigation, Eurocode 8, civil engineering, construction
• Work type: Scientific work
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2020
• Number of pages: Str. 1-15
• Numbering: Letn. 67/104269
• PID: 20.500.12556/RUL-124736
• UDC: 624.042.7
• ISSN on article: 0950-4230
• DOI: 10.1016/j.jlp.2020.104269
• COBISS.SI-ID: 37389827
• Publication date in RUL: 13.02.2021

Record is a part of a journal

• Title: Journal of loss prevention in the process industries
• Shortened title: J. loss prev. process ind.
• Publisher: Elsevier
• ISSN: 0950-4230
• COBISS.SI-ID: 20884519

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
• Licensing start date: 13.02.2021

Secondary language

• Language: Slovenian
• Keywords: plavajoča streha, jekleni rezervoarji, poenostavljeni modeli, podrobni modeli, analiza potresnega tveganja, zmanjšanje tveganja, Evrokod 8, gradbeništvo, konstrukcije

Projects

• Funder: EC - European Commission
• Project number: 721816
• Name: Extreme loading analysis of petrolchemicals plants and design of metamaterial-based shields for enhanced resilience
• Acronym: XP-RESILIENCE