Volume 8 -                   ijmt 2017, 8 - : 59-64 | Back to browse issues page

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1- Petroleum University of Technology
2- Assistant Professor Petroleum University of Technology
Abstract:   (622 Views)
The study about the jacket platforms in the past has revealed that the most of the collapse failures occur due to the lack of strength of the pile foundation. However, when the jacket platforms which have been collapsed due to extreme condition were looked into, it was found that most of them had their foundations intact. These contrasting facts can be explained with the help of the phenomenon called “aging of piles”. Aging effect of piles has been proven by experiments indicating gradual increase in pile capacity which is due to the thixotropic characteristics of clayey soils, leading to gradual improvement of soil clamping property. But due to lack of proper understanding and suitable techniques to incorporate them, these aging effects have been ignored during the pushover analysis. In this study, a simple technique of stepping up of the soil curves in order to accommodate the increase in capacity of pile foundation due to aging is utilized, and then the pushover analysis is performed using commercial software SACS. SPD19C (South Pars gas field Development, phase 19) is a new constructed jacket platform in Persian Gulf which is used as the case study in this paper. The platform is considered to be under the storm condition in 180º direction which is the worst condition. This study shows that the incorporation of pile aging effect results in the improvement the piles performance and Reserve Strength Ratio (RSR) about 10 percent. This research also has provided a deeper knowledge into the behavior of aged offshore jacket platforms.
Full-Text [PDF 383 kb]   (132 Downloads)    
Type of Study: Research Paper | Subject: Offshore Structure
Received: 2017/05/27 | Accepted: 2017/11/25

1. Nichols, N. W., Goh, T. K. and Bahar, H., (2006), Managing Structural Integrity for Aging Platform, in SPE Asia Pacific Oil and Gas Conference and Exhibition, Adelaide,Australia,. [DOI: 10.2118/101000-MS]
2. George, J. M., Wahab, M. M. A., and Kurian, V. J., (2016), Changes in The Pushover Analysis of Offshore Jacket Platforms Due to The Incorporation of The Aging Effect of Piles, ARPN Journal of Engineering and Applied Science , vol. 11.
3. Gilbert, R. B., Chen, J. -Y., Materek, B., Puskar, F., Carpenter, J. and Young, A., (2010), Comparison of Observed and Predicted Performance for Jacket Pile Foundations in Hurricanes, in Offshore Technology, Houston, Texas, USA.
4. George, J. M., Wahab, M. M. A. and Kurian, V. J., (2015), Estimation of Aging Effects of Piles in Malaysian Offshore Locations, Journal of Engineering Science and Technology, (In publication).
5. El-Reedy, M. A., (2014). Marine Structural Design Calculations, United Kingdom: Butterworth Heinemann.
6. Clarke, J., (1993), Large-Scale Pile Tests in Clay, London: Thomas Telford.
7. Bogard, J. D. and Matlock, H., (1990), Applications of model pile tests to axial pile design, in Proceedings of the 22nd Annual Offshore Technology Conference, Houston Texas. [DOI: 10.4043/6376-MS]
8. komurka, V. E., Wagner, A. B. and Edil, T. B., (2003), Estimating soil/pile set-up, The Wisconsin Highway Research Program (WHRP).
9. Lied, E. K. W., (2006), A Study of Time Effects on Pile Capacity NGI Report, Norwegian Geotechnical Institute, Norway.
10. Skov, R. and Denver, H., (1988), Piles TimeDependence of Bearing Capacity of Piles, in Proceedings of the 3rd international conference on the application of stress-wave theory to piles, Ottawa, Canada.
11. Bentley Systems, (2010). SACS Software Manual, From Engineering Dynamics Inc.
12. Narayanan, S. P. and Kabir, M., (2009), Structural Integrity Management for Fixed Offshore Platform in Malaysia, Malaysia: World Academy of Science, Engineering and Technology. [DOI: 1999.3/6666]
13. DIN, German Institute for Standardization, German: Deutsches Institut fur Normung.
14. API, (2013), Structural Integrity Management of Fixed Offshore Structures, American Petrolume Institute. [DOI: 10.4043/20675-MS]