Browse > Article
http://dx.doi.org/10.7837/kosomes.2020.26.1.103

A Study on Load-carrying Capacity Design Criteria of Jack-up Rigs under Environmental Loading Conditions  

Park, Joo Shin (Ship and Offshore Research Institute, Samsung Heavy Industry Co. Ltd.)
Ha, Yeon Chul (The Korea Ship and Offshore Research Institute, Pusan National University)
Seo, Jung Kwan (The Korea Ship and Offshore Research Institute, Pusan National University)
Publication Information
Journal of the Korean Society of Marine Environment & Safety / v.26, no.1, 2020 , pp. 103-113 More about this Journal
Abstract
Jack-up drilling rigs are widely used in the offshore oil and gas exploration industry. Although originally designed for use in shallow waters, trends in the energy industry have led to a growing demand for their use in deep sea and harsh environmental conditions. To extend the operating range of jack-up units, their design must be based on reliable analysis while eliminating excessive conservatism. In current industrial practice, jack-up drilling rigs are designed using the working(or allowable) stress design (WSD) method. Recently, classifications have been developed for specific regulations based on the load and resistance factor design (LRFD) method, which emphasises the reliability of the methods. This statistical method utilises the concept of limit state design and uses factored loads and resistance factors to account for uncertainly in the loads and computed strength of the leg components in a jack-up drilling rig. The key differences between the LRFD method and the WSD method must be identified to enable appropriate use of the LRFD method for designing jack-up rigs. Therefore, the aim of this study is to compare and quantitatively investigate the differences between actual jack-up lattice leg structures, which are designed by the WSD and LRFD methods, and subject to different environmental load-to-dead-load ratios, thereby delineating the load-to-capacity ratios of rigs designed using theses methods under these different enviromental conditions. The comparative results are significantly advantageous in the leg design of jack-up rigs, and determine that the jack-up rigs designed using the WSD and LRFD methods with UC values differ by approximately 31 % with respect to the API-RP code basis. It can be observed that the LRFD design method is more advantageous to structure optimization compared to the WSD method.
Keywords
Design Criteria; Working Stress Design (WSD); Load and Resistance Factored Design (LRFD); Jack-up Rig; Leg Structures;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
연도 인용수 순위
1 Tan, X. M. and J. Lu(2003), Structural behavior prediction for jack-up units during jacking operations, Computer and Structures, Vol. 81, pp. 2409-2416.   DOI
2 Williams, M. S., R. S. G. Thompson, G. T. Houlsby(1999), A parametric study of the non-linear dynamic behavior of an offshore jack-up unit, Engineering Structures, Vol. 21, pp. 383-394.   DOI
3 American Institute of Steel Construction (AISC) (1989), Specification for structural steel buildings, Allowable stress design and plastic design.
4 American Petroleum Institute (API) (1993), Recommended practice for planning, designing and constructing fixed offshore platforms-Load and Resistance Factor Design.
5 Lewis, D. R. and J. Brekke(2006), Site assessment for jack-ups in Gulf of Mexico, 2006 Offshore Technology Conference, Houston, Texas, USA.
6 ASME(2017), International code, Boiler and Pressure Vessel, Sec. Powered Boilers and Sec. Pressure Vessels.
7 DNV-RP-C104(2011), Self Elevating Units, Recommended Practice, Det Norske Veritas, Oslo.
8 ISO(2016), Petroleum and natural gas industries, Site specific assessment of mobile offshore units, Part 1, Jack-ups (2nd edition).
9 Ma, K. Y., J. H. Kim, J. S. Park, J. M. Lee, and J. K. Seo(2019), A study on collision strength assessment of a jack-up rig with attendant vessel, International Journal of Naval Architecture and Ocean Engineering (doi.org/10.1016/j.ijnaoe.2019.10.002).
10 Morandi, A. C., P. A. Frieze, M. Birkinshaw, D. Smith, and A. Dixon(1999), Jack-up and jacket platforms: a comparison of system strength and reliability, Marine Structures, Vol. 12, pp. 311-325.   DOI
11 American Concrete Institute (ACI) (1995), Building code requirements for reinforced concrete.
12 Paik, J. K. and A. K. Thayamballi(2007), Ship-Shaped Installations: design, building, and operation, Cambrige Univesity Press, UK.
13 SACS user's manual(2016), Introduction of linear and nonlinear analysis and it's application of shell modeling Vol. 2, pp. 50-65.
14 SNAME RP 5A-5(2002), Guidelines for Site Specific Assessment of Mobile Jack-Up Units, Technical & Research Bulletin 5-5A, The Society of Naval Architects and Marine Engineers, Offshore Committee.