ISO TR 19905-2-2012 Petroleum and natural gas industries - Site-specific assessment of mobile offshore units - Part 2 Jack-ups commentary and detailed sample ca.pdf

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1、 Reference number ISO/TR 19905-2:2012(E) ISO 2012TECHNICAL REPORT ISO/TR 19905-2 First edition 2012-12-15 Petroleum and natural gas industries Site-specific assessment of mobile offshore units Part 2: Jack-ups commentary and detailed sample calculation Industries du ptrole et du gaz naturel valuatio

2、n lie au site des units marines mobiles Partie 2: Complments sur les plates-formes auto-lvatrices ISO/TR 19905-2:2012(E) COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, elect

3、ronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.o

4、rg Web www.iso.org Published in Switzerland ii ISO 2012 All rights reservedISO/TR 19905-2:2012(E) ISO 2012 All rights reserved iiiContents Page Foreword .v Introduction.vii 1 Scope1 2 References .1 3 Terms and definitions .1 4 Symbols1 4.1 Symbols for Clause 61 4.2 Symbols for Clause 73 4.3 Symbols

5、for Clause 85 4.4 Symbols for Clause 96 4.5 Symbols for Clause 106 4.6 Symbols for Clause 128 5 Commentary on ISO 19905-1:2012, Clauses 5 and A.5 .8 6 Commentary on ISO 19905-1:2012, Clauses 6 and A.6 .8 TR.6.4.1 Metocean data General8 TR.6.4.2 Waves 8 TR.6.4.3 Current.20 TR.6.4.4 Water depths.20 TR

6、.6.4.5 Wind .21 7 Commentary to ISO 19905-1:2012, Clauses 7 and A.7 24 TR.7.1 Scope 24 TR.7.3.2 Hydrodynamic model .24 TR.7.3.2.1.1 Length of members 24 TR.7.3.2.1.2 Spudcan.24 TR.7.3.2.1.3 Shielding and solidification.24 TR.7.3.2.2 “Detailed” leg model .25 TR.7.3.2.3 “Equivalent” leg model .25 TR.7

7、.3.2.3.1 Equivalent drag coefficient25 TR.7.3.2.3.2 Equivalent inertia coefficient.26 TR.7.3.3 Wave and current actions48 TR.7.3.4 Wind actions .57 TR.7.8 Other considerations.57 APPENDIX TR.7.A : Example of equivalent model computations.58 APPENDIX TR.7.B: Comparison cases to assess implications of

8、 the ISO 19905-1 formulation .63 APPENDIX TR.7.C: Comparison of test results for chords67 8 Commentary to ISO 19905-1:2012, Clauses 8 and A.8 70 TR A.8.8.6 Derivation of the alternative simplified negative stiffness correction term for P- effects .70 9 Commentary to ISO 19905-1:2012, Clauses 9 and A

9、.9 77 TR.9.3.6.2 Derivation of the limiting horizontal reaction given in ISO 19905-1:2012, Table A.9.3.7 77 10 Commentary to ISO 19905-1:2012, Clauses 10 and A.10 79 TR.10.4.2.1 Natural period General .79 TR.10.4.2.2 Derivation of K e , effective stiffness used to calculate the jack-up natural perio

10、d82 TR.10.4.3.3 Hysteretic damping .95 TR.10.4.3.4 Vertical radiation damping in earthquake analysis .96 TR.10.5.3.4 / C.2.4 Guidance on the fourth method of ISO 19905-1:2012, Table A.10.5.1 Application of the drag-inertia method .96 ISO/TR 19905-2:2012(E) iv ISO 2012 All rights reserved11 Commentar

11、y to ISO 19905-1:2012, Clauses 11 and A.11.96 12 Commentary to ISO 19905-1:2012, Clauses 12 and A.12.96 TR.12.6.2.2 Nominal bending strength 96 TR.12.6.2.2.1 Example .96 TR.12.6.3.2 Background for in interaction equation approach97 13 Commentary to ISO 19905-1:2012, Annex C .98 TR.C.2.4 Guidance on

12、the fourth method of ISO 19905-1:2012, Table A.10.5.1 Application of the drag-inertia method.98 Annex A (informative) Detailed example calculation.99 Annex B (informative) SIPM “drag-inertia method” for dynamic analysis and estimation of extreme response for jack-ups.266 Bibliography 295 ISO/TR 1990

13、5-2:2012(E) ISO 2012 All rights reserved vForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member

14、body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electr

15、otechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted

16、 by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In exceptional circumstances, when a technical committee has collected data of a different kind from that whic

17、h is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides

18、 are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TR 19905-2 was prepared by Technical Committee I

19、SO/TC 67, Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures. ISO 19905 consists of the following parts, under the general title Petroleum and natural gas industries Site- specific assessment of mobile offshore

20、 units: Part 1: Jack-ups Part 2: Jack-ups commentary and detailed sample calculation Technical Report The following part is under preparation: Part 3: Floating units ISO/TR 19905-2:2012 was prepared in 2012 and is referenced as ISO/TR 19905-2:2012. Users are advised, however, that it was published,

21、and only became available, in 2013. ISO 19905 is one of a series of International Standards for offshore structures. The full series consists of the following International Standards: ISO 19900, Petroleum and natural gas industries General requirements for offshore structures ISO 19901-1, Petroleum

22、and natural gas industries Specific requirements for offshore structures Part 1: Metocean design and operating considerations ISO 19901-2, Petroleum and natural gas industries Specific requirements for offshore structures Part 2: Seismic design procedures and criteria ISO 19901-3, Petroleum and natu

23、ral gas industries Specific requirements for offshore structures Part 3: Topsides structure ISO/TR 19905-2:2012(E) vi ISO 2012 All rights reserved ISO 19901-4, Petroleum and natural gas industries Specific requirements for offshore structures Part 4: Geotechnical and foundation design considerations

24、 ISO 19901-5, Petroleum and natural gas industries Specific requirements for offshore structures Part 5: Weight control during engineering and construction ISO 19901-6, Petroleum and natural gas industries Specific requirements for offshore structures Part 6: Marine operations ISO 19901-7, Petroleum

25、 and natural gas industries Specific requirements for offshore structures Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units ISO 19901-8 1) , Petroleum and natural gas industries Specific requirements for offshore structures Part 8: Marine soil investigations I

26、SO 19902, Petroleum and natural gas industries Fixed steel offshore structures ISO 19903, Petroleum and natural gas industries Fixed concrete offshore structures ISO 19904-1, Petroleum and natural gas industries Floating offshore structures Part 1: Monohulls, semi-submersibles and spars ISO 19905-1,

27、 Petroleum and natural gas industries Site-specific assessment of mobile offshore units Part 1: Jack-ups ISO/TR 19905-2, Petroleum and natural gas industries Site-specific assessment of mobile offshore units Part 2: Jack-ups commentary and detailed sample calculation ISO/TR 19905-3 1) , Petroleum an

28、d natural gas industries Site-specific assessment of mobile offshore units Part 3: Floating units ISO 19906, Petroleum and natural gas industries Arctic offshore structures 1) Under preparation. ISO/TR 19905-2:2012(E) ISO 2012 All rights reserved viiIntroduction The series of International Standards

29、 applicable to types of offshore structures, ISO 19900 to ISO 19906, addresses design requirements and assessments for all offshore structures used by the petroleum and natural gas industries worldwide. Through their application, the intention is to achieve reliability levels appropriate for manned

30、and unmanned offshore structures, whatever the type of structure and the nature or combination of the materials used. It is important to recognize that structural integrity is an overall concept comprising models for describing actions, structural analyses, design or assessment rules, safety element

31、s, workmanship, quality control procedures and national requirements, all of which are mutually dependent. The modification of one aspect of the design or assessment in isolation can disturb the balance of reliability inherent in the overall concept or structural system. The implications involved in

32、 modifications, therefore, need to be considered in relation to the overall reliability of offshore structural systems. The series of International Standards applicable to the various types of offshore structure is intended to provide a wide latitude in the choice of structural configurations, mater

33、ials and techniques without hindering innovation. Sound engineering judgement is therefore necessary in the use of these International Standards. ISO 19905-1 was developed from SNAME T new calculation techniques have been addressed because of improved computational capabilities allowing more complex

34、 assessments; gaps that existed in the original SNAME T and changes have been made to align ISO 19905-1 with other standards within the 19900 series. A description of the more important changes, along with the reasoning for the changes, can be found in a series of papers published in 2012 by Offshor

35、e Technology Conference. These papers can be of considerable value in helping the analyst, particularly those who are familiar with SNAME T used for airgap calculations H mpmwave height associated with H srp , equivalent to the height between the extreme crest and the following trough H moestimate o

36、f H ssignificant wave height (metres) H sscaled significant wave height to be used in irregular seas simulation (metres) H srpsignificant wave height for assessment return period k wave number m power constant in the () 2 cos m spreading function S nn (f) power density of wave surface elevation as a

37、 function of wave frequency T wave period (seconds) T wind averaging time (seconds) T 0 standard reference time averaging interval for wind speed of 1 h = 3 600 s T ppeak period in wave spectrum (seconds) T zzero-upcrossing period of wave spectrum (seconds) U wind speed U w,T (10) is the sustained w

38、ind speed at 10 m height above mean sea level U w0 is the 1 h sustained wind speed at the reference elevation 10 m above mean sea level u the computed velocity for long crested waves u redthe reduced horizontal velocity V current velocity equilibrium range parameter 3skewness 4kurtosis peak enhancem

39、ent factor dscaling of drag forces kinematics reduction factor crest elevation by Airy theory ISO/TR 19905-2:2012(E) ISO 2012 All rights reserved 3 screst elevation by Stokes directional spreading factor defined in ISO 19901-1 spectral peakwidth parameter 4.2 Symbols for Clause 7 A cross-sectional a

40、rea of member A eequivalent area of leg per unit height A iequivalent area of element A ssum of projected areas for all members in the considered plane A ttotal projected envelope area of the considered plane C Aadded mass coefficient C Ddrag coefficient C Dodrag coefficient for chord at direction =

41、 0 C D1drag coefficient for flow normal to the rack, = 90 C Deequivalent drag coefficient C Deiequivalent drag coefficient of member i C Didrag coefficient of an individual member, related to D iC Dpr ( ) drag coefficient to the projected diameter C Droughdrag coefficient for a rough member C Dsmoot

42、hdrag coefficient for a smooth member C Minertia coefficient C Meequivalent inertia coefficient C Meiequivalent inertia coefficient of member i C Miinertia coefficient of a member, related to D id mean, undisturbed water depth (positive) D member diameter D eequivalent diameter of leg bay D Fface width of leg, outside dimensions D ireference dimension of individual leg members D pr () projected diameter of the chord f ifundamental vibration frequencies of the member H ssignificant wave height