Development of Two-Variable Fragility Functions for Piping Systems in Industrial Plants

Document Type : Original Article

Authors

1 Associate professor, Structural Engineering Research Centre, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

2 Faculty of Engineering, Civil Engineering Department, Structural Engineering Group , Islamic Azad University, Tehran South Branch, Tehran, Iran

Abstract

Regarding that refineries are essential facilities in oil and gas industries, evaluation of their equipment’s vulnerability, including piping systems, tanks and … subjected to natural hazards is of great importance. This issue is more crucial in Iran as a highly seismic country. In this research a case study has been carried out with the aim of seismic evaluation of a part of piping system of Isomax unit of Tehran oil refinery. For this purpose, first all required information and drawing maps have been gathered to identify the materials’ characteristics, geometry, and applied loadings. Then, the considered piping system has been modeled in ABAQUS finite element software, subjected to gravity, internal pressure and 3-component earthquake acceleration records of 157 earthquakes, by time history analyses (THA). In the third stage, by using the maximum von Mises stress in the piping system for all 157 cases of THA, the single-variable fragility curves, once by using PGA, and once more using PGV as the IM, have been developed. Finally, the two-variable fragility function (fragility surface) has been developed for the piping system. Results show that the two-variable fragility functions are much more reliable than single-variable ones. Results also show that the two knees in the piping system are the more vulnerable parts.

Keywords

Main Subjects


[1] Krausmann, Elisabeth. (2010). The impact of the 12 May 2008 Wenchuan earthquake on industrial facilities. Journal of Loss Prevention in the Process Industries, 23, 242-248. doi:10.1016/j.jlp.2009.10.004
 [2] Fu, Zhiwei. (2013). Study on Seismic Fragility Analysis for Piping of CEFR. Journal of Applied Mathematics and Physics, 1, 82-88. doi:10.4236/jump.2013.16016
 [3] Lanzano, Giovanni. (2013). Seismic vulnerability of natural gas pipelines. Journal of Reliability Engineering and System Safety, 117, 73-80. doi:10.1016/j.ress.2013.03.019
 [4] S. Razzaghi, Mehran. (2014). Probabilistic Seismic Safety Evaluation of Precode Cylindrical Oil Tanks. Journal of Performance of Constructed Facilities, 04014170. doi: 10.1061/(ASCE)CF.1943-5509.0000669
 [5] Reza, M.S. (2014). Enhanced Seismic Performance of Non-Standard Bolted Flange Joints for Petrochemical Piping Systems. Journal of Loss Prevention in the Process Industries, 30, 124-136. doi: 10.1016/j.jlp.2014.05.011
 [6] Gyu, Bub. (2014). Seismic Fragility Evaluation of Base Isolated Nuclear Power Plant Piping System. In: International Conference on Thin-Walled Structures. Busan, Korea: ICTWS2014,8 pages.
 [7] Ju, Bu Seog. (2015). Seismic Fragility of Threaded Tee-Joint Connections in Piping Systems. Journal of Pressure Vessels and Piping, 132-133, 106-118. doi: 10.1016/j.ijpvp.2015.06.001
 [8] Salimi Firoozabad, Ehsan. (2016). Seismic Fragility of APR1400 Main Steam Piping System. In: International Conference on Probabilistic Safety Assessment and Management. Seoul, Korea: PSAM 13,9 pages.
 [9] Phan, Hoang Nam. (2016). Fragility Analysis Methods for Steel Storage Tanks in Seismic Prone Areas. In: International Conference on Pressure Vessels and Piping. Vancouver, British Columbia, Canada: ASME 2016,9 pages.
 [10] Caprinozzi, Stefano. (2017).Univariate Fragility Models for Seismic Valnerability Assessment of Refinery Piping Systems. In: International Conference on Pressure Vessels and Piping. Waikoloa, Hawaii, United States: ASME 2017, 10pages.
[11] Zareei, Seyed Alireza. (2017). Evaluation of power substation equipment seismic vulnerability by multivariate fragility analysis: A case study on a 420 kV circuit breaker.  Journal of Soil Dynamics and Earthquake Engineering, 92, 72-94. doi: 10.1016/j.soildyn.2016.09.026
[12] Moayeri, Hamed. and Forouzesh,Farinaz. (2014). Finite Element Analysis of Engineering Problems by Abaqus. Tehran:Danesh Bonyad, 805.
[13] Nowak, Andrzej S. and Collins,Kevin R. (2012). Reliability of Structures. New York: CRC Press, 407.
[14] Ghalyani, Ehsan. (2018). Development of two-variable fragility functions for piping systems in industrial plants. M.Sc. Islamic Azad University,South Tehran Branch.