Seismic Vulnerability Assessment of Jacket Type Offshore Platforms

Document Type : Regular Paper

Author

Department of Civil Engineering, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran

Abstract

Most of oil and gas offshore platforms are located in the seismic regains. Therefore, Seismic vulnerability evaluation of the offshore platforms is one of the essential vital issues in the structural systems. In this article, jacket type offshore platforms are examined by incorporating the pushover analyses and nonlinear time history analyses, in such a way that, first some push over analyses are performed to detect the more critical members of the jacket platform in consonance with the range of their plastic deformations. Subsequently, nonlinear time history analyses are performed, concentrating on the critical members, to examine the vulnerability of the jacket platform under intensive earthquake loads. Pursuant to the numerical results, the combination of the push over analyses and nonlinear time history analyses proposes a reliable and swift seismic assessment procedure to evaluate the seismic vulnerability of the offshore platforms. Moreover, seismic vulnerability of the offshore structures is dependent on the critical member locations and their load bearing situations in the offshore structures.

Keywords

Main Subjects


[1] Asgarian, B., Aghakouchack, A. (2004). “Nonlinear Dynamic Analysis of Jacket Type Offshore Structures Subjected to Earthquake Using Fiber Elements.” Proceedings of the 13th World Conference on Earthquake Eng. Conference, Vancouver, Canada.
[2] Asgarian, B., Ajamy, A. (2006). “Nonlinear Dynamic Behavior of Offshore Structures, Using Incremental Dynamic Analysis.” Proceedings of the 8th US National Conference on Earthquake Eng. (100th Anniversary Earthquake Conference), San Francisco.
[3] Banon, H., Bea, R. G., Bruen, F. J., Cornell, C. A., Krieger, W. F., Stewart, D. A. (1994). “Assessing Fitness for Purpose of Offshore Platforms: I) Analytical Methods and Inspections.” Journal of Structural Eng, Vol. 120, no. 12, pp. 3595-3612.
[4] Banon, H., Bea, R. G.; Bruen, F. J.; Cornell, C. A.; Krieger, W. F. and Stewart, D. A. (1994). “Assessing Fitness for Purpose of Offshore Platforms: II) Risk Management, Maintenance, and Repair.” Journal of Structural Eng, Vol. 120, no. 12, pp. 3613-3633.
[5] Kamil, H. (1978). “Nonlinear design of offshore structures under extreme loading conditions.” Proceedings of the Tenth Annual Offshore Technology Conference, pp. 39-48.
[6] Karimiyan, S. (2008). “Seismic Reliability Analysis of Offshore Structures by Using Nonlinear Time History Analyses.” Master Thesis under supervision of Dr. Mahmood Hosseini, Submitted to Civil Engineering Department, Graduate School, Tehran South Branch of the Islamic Azad University (IAU), Tehran, Iran.
[7] Kawano, Kenji., Kukusako, Hisasi., Iida, Takesi. (2003).“Seismic Response Evaluations of an Offshore Structure with Uncertainties.” Proceedings of ISOPE-2003, Thirteenth International Offshore and Polar Engineering Conference, Vol. 4, pp. 473-479.
[8] Lee, Hsien Hua. (1998). “Seismic and vibration mitigation for the A-type offshore template platform system.” Structural Eng and Mechanics, Vol. 6, no. 3, pp. 347-362.
[9] Ueda, S., Shiraishi, S. (1979). “Observation of oscillation of a deep water platform and the ground during earthquakes.” Proceedings of the Eleventh Annual Offshore Technology Conference, pp. 2225-2234.
[10] Watt, B. J. (1978). “Earthquake survivability of concrete platforms.” Offshore Technology Conference, Proceedings of Tenth Annual, pp. 957-973.
[11] Zayas, V. A., Shing, P.-S. B., Mahin, S. A., Popov, E. P. (1981). “Inelastic structural modeling of braced offshore platforms for seismic loading.” Earthquake Engineering Research Center, University of California Berkeley, 148 pages.
[12] Chung, N. T., Anh, L.h., (2015). “Dynamic analysis of Jacket type offshore structure under impact of wave and wind using Stoke’s second order wave theory.” Journal of marine sceince and thecnology, Vol. 15, No. 2. DOI: 10.15625/1859-3097/15/2/6507.
[13] Zolfaghari, M. R., Ajamy, A., Asgarian, B., (2015). “A simplified method in comparison with comprehensive interaction incremental dynamic analysis to assess seismic performance of jacket-type offshore platforms.” International Journal of Advanced Structural Engineering (IJASE),Vol. 7, Issue 4, pp 353–364.
[14] Junbo, J. (2016). “Influence of hydrodynamic forces and ice during earthquakes.” Modern Earthquake Engineering,  pp. 361-378.
[15] Lotfollahi-Yaghin, M. A., Ahmadi, H., Tafakhor, H. (2016). “Seismic responses of an offshore jacket-type platform incorporated with tuned liquid dampers.” Advances in Structural Engineering, Vol. 19, Issue 2.
[16] Kandasamy, R., Cui, F.Townsend, N., Chiang F., C., Guo, J., Shenoi, A., Xiong, Y. (2016). “A review of vibration control methods for marine offshore structures.” Ocean Engineering, Vol. 127, PP. 279-297.