Comments On ISO/CD'F' 19905-1 · Web view“preload, leg penetration, bearing capacity” US1...

Comments On ISO/CD'F' 19905-1

Template for comments and secretariat observations

Date:

Document: ISO/

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MB1

Clause/Subclause/Annex/Figure/Table(e.g. 3.1, Table 2)

Paragraph/List item/Note/(e.g. Note 2)

Type of com-ment2

Comment (justification for change)

Proposed change

Secretariat observationson each comment submitted

Template for comments and secretariat observations

Date: 2007-04-16

Document: ISO/CD’F’ 19905-1

1

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(3)

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MB1

Clause No./Subclause No./Annex(e.g. 3.1)

Paragraph/Figure/Table/Note(e.g. Table 1)

Type of com-ment2

Comment (justification for change) by the MB

Proposed change by the MB

Secretariat observationson each comment submitted

KR

G

The KATS supports the above document without comments.

NL

ge

While there is definite progress compared to a previous draft, this CD ‘F’ still requires substantial further work to enable a full and detailed review of the draft document, editorially as well as regarding technical content.

NL

ge

In line with the guidance for reviewers by the WG and given at the front of the document, the annexes have only been considered at a rather high level for technical intent. Where applicable, comments on clauses in Annex A are given immediately following the same clause in the normative. However, comments are restricted to main issues. Absence of further comments should not be interpreted as agreement with the text as written.

NL

ge

For certain (sub)clauses editorial corrections or suggestions for text changes are proposed that are too cumbersome too describe in the format of this Table. These items are collected in a separate WORD document accompanying the Table, using the text in the document with ‘track changes’. The occasions are marked with “see accompanying Word document” in col. 6.

see accompanying Word document

UK

ge


UK

ge


US1

ge


US1

ge


US2

Ge

Overall the document appears to be way to complex for the practitioners who might be using the document. In places the document is confusing and requires the reader to constantly be referring back to Annex A to understand the abbreviated terms.

US2

Ge

This whole document needs to have several more iterations by the authors before being asked to be reviewed. I am also not sure that it shouldn’t be broken down into smaller independent documents that deal with specific topics rather than attempting to make it a catch all document that is both cumbersome and bulky and requires a number of disciplines to review.

US2

Ge

Providing a list of terms and definitions is a good way to allow users to quickly reference a terms or definition. However, may of the equations are given using these abbreviations as well as not providing an illustrations to represent exactly what these terms are referring. It would be most helpful to simplify the equations and to present an illustration especially in section 9.3 Geotechnical Analysis of independent leg foundations

NL

throughout

te/ed

Symbols and references: Use of symbols and references should be decided and rationalized. Do not let this wait till the end, as a last resort type of activity.

See also comments to Clause 4 and the Bibliography.

Follow ISO Directives and usage.

Use symbols as far as possible in accordance with ISO recommended symbols. Same for references.

NL

throughout

te/ed

Use of verbal forms in ISO standards:

- “may” should exclusively be used for a permission, not to express a possibility or uncertainty (neither in the normative nor in the informative); needless to say that “might” is even worse;

- informative annexes cannot contain requirements, i.e. “shall” is normally not permitted (an exception is in the description of an alternative method which, if chosen, has mandatory procedures associated with it);

- “is/are to be” is equivalent to “shall”; the latter form is recommended; the former discouraged;

- the word “must” is associated with regulatory provisions and should not be used in an ISO standard;


If in clauses in Annex A certain provisions are really intended to be requirements, the text containing “shall” should be moved to the normative in the main body of the standard.

NL

throughout

ed

Use of capitals: Capitals are only used at the beginning of a sentence, for abbreviations and in names (not for terms or special words). Also, when a list is a continuation of the introductory sentence the bullet points do not begin with capitals.


NL

throughout

ed

Units: use only ‘abbreviated’ forms to indicate units, e.g. m, km, h, s, min; do not write the words out in full.


NL

throughout

ed

Decimal comma: use decimal commas, not decimal points.


NL

throughout

te/ed

Precision and clarity: in several places formulations lack precision and clarity.

Review both normative and informative for improvements. In some instances change proposals are given in this table or in the accompanying Word document.

NL

throughout

te/ed

Phrases: For clarity and consistency ensure that the same terms and phrases are used throughout the document.

Wherever possible, also ensure consistency with terms and phrases used in other ISO 19900 standards.

· use “extreme storm event” consistently to refer to assessment situations [a defined term]

· use “mode” consistently to refer to situations in which the ju operates [drilling mode, elevated mode, etc.]

· use “sea floor” instead of “mudline” [mudline is not used in ISO 19901-4, nor in 19901-7, 19902 or 19903]

· “seabed surface” is in many places best replaced by “sea floor” [sea floor and seabed are defined in ISO 19901-4 and these terms are used throughout the 19900 series]

· “No guidance is offered.” [is the standard phrase used in all ISO 19900 standards]

NL

throughout

te/ed

Terminology: We are pleased to see that the term “action” is increasingly adopted. However, there is not yet consistency throughout the document (neither in the normative, nor in the annexes). Common expressions such as “load arrangement”, “load case”, “loadset”, “load path”, “load transfer”, “load carrying”, etc. are maintained.The distinction between “load” and “force” in the 19900 series is that “load” refers to (externally) applied actions, whereas “force” refers to action effects. Reactions are an action effect, hence reaction forces, as are internal forces in a component, in the soil, and also inertial forces due to accelerations from global response. See also comments on e.g. 7.6 and 9.3.

Review and adjust document as applicable for correctness and consistency in terminology.

NL

throughout

ed

Spelling: As the SC 7 secretariat is the national standards body in the UK, spelling should be UK English. Further, apply to the greatest extent possible consistent spelling (including use of hyphens, comma’s, etc.) throughout the document, as well as consistent with other ISO 19900 standards.

· 50 year, 100 year [without hyphen]

· e.g. [remove comma after e.g.]

· jackhouse [one word?]

· life-safety [with a hyphen]

· long-term [with a hyphen]

· non-linear [with hyphen]

· sea floor [two words]

· sea water [two words]

· short-term [with a hyphen]

· subclause [no hyphen]

· s/z for British spelling

· two-dimensional, three-dimensional [with a hyphen]

NL

throughout

ed

ISO 19905: 19905 consists of 2 parts; referring to 19905-1 should be done as “this part of International Standard 19905”, or more simply as “this document”; the use of “this standard” is unspecific and not correct.

NL

Introduction

ed

Use ISO FDIS 19902 as a model for paras 1, 2 and 3. Bring the introduction generally in line with other standards in the ISO 19900 series. Use”‘standard phrases” as agreed to by ISO CS earlier. Furthermore, see suggestions for some improvements.


NL

1

ed

Change “this standard” (see earlier comment).

Use consistent terminology: the document is all about “site-specific assessment”, not about assessment in general.Further suggestions for some improvements.


NL

2

te/ed

Use ‘boiler plate text’ for introductory sentence(s) and include only those standards that are called on in the document in a normative manner (other than Clause 3).

ISO 19901-3, 19901-5 and 19901-6 may be referred to if useful (in on-binding terms) but should not be normative.

ISO 19900 is agreed and is normative.

ISO 19901-1 is agreed and is normative, but is only called up in Annex A; add an appropriate reference in the body of the document.

ISO 19901-2 and 19901-4 should also be normative, but are presently not called up in the document. Appropriate references should be added.

ISO 19902 is agreed and is normative, where applicable.

NL

3

ed

Definitions should not begin with a capital letter, not with an article, and not be closed off with a full stop.

Defined terms within definitions should not be in italics.

One or more of these errors occur in:

3.9assessment

3.10assessment situation

3.12assessor

3.20consequence category

3.29extreme storm event

3.40independent leg jack-up

3.44jack-up

3.46leaning instability

3.52load arrangement

3.56load case

3.58mat-supported jack-up

3.67operations manual

3.69permanent load

3.76regulator

3.89skirted spudcan

NL

3

te/ed

We question the excessive number of definitions.

It can be useful to repeat terms that are already defined in standards named in the introductory sentence(s) of Clause 3, but it is not necessary to do this for all terms that also appear in ISO 19905-1. Use repetition more by exception than as a rule.

Clause 3 further unnecessarily includes very common and well-known terms, as well as terms that do not have other meanings than in the dictionary. We suggest to delete the definitions shown in the next column.

Delete:

3.2abnormal wave crest

3.6direct actions [given within 3.5]

3.7indirect actions [given within 3.5]

3.19component [use “structural component” (see also comment with 3.103), and use “component” as shorthand in texts where there is no possibility for confusion or uncertainty]

3.27element [in ISO 19902 element is only used in connection with “finite element”; use otherwise “structural component” or “part”; see also 3.19, 3.61 and comment with 3.103]

3.34geoscience studies [see also 3.42]

3.35geotechnical investigation

3.37hard sloping strata

3.39individual extreme environmental values [Perfectly clear without definition. Is “in the same direction” always the case, without exception? Specific circumstances can best be noted where these occur or are relevant.]

3.41independent leg foundation [covered by 3.40 and 3.31]

3.42integrated study [if really considered essential, then link with 3.34 - geoscience studies]

3.47leg extraction [obvious and unnecessary]

3.48leg inclination [obvious and unnecessary]

3.51liquefaction / cyclic mobility

3.57magnetometer survey

3.61member [see also 3.19, 3.27 and comment with 3.103]

3.66open water site [obvious and unnecessary]

3.83sea floor instability [see also comment with 3.83 further down]

3.86shallow seismic [unnecessary to define a general technique in this document]

3.87sidescan sonar [unnecessary to define a general technique in this document]

3.92sliding resistance [obvious and unnecessary]

3.93solidification effect [see also comment with 3.93 further down]

3.97squeezing

3.98spudcan-pile interaction

US2

3

Swiss Cheesing should be added as a term to the definitions defining a method to reduce the potential for a punch through by pre-drilling a grid of hole within each spud can area that has the potential for a punch through situation

NL

3

introductory sentences

ed

Modifications proposed.


NL

3.1

definition

ed

“Design” is not part of 19905-1 and is therefore best deleted. We suggest also deleting the word “conventional”.

Change to:

assessment situation in which conditions exceed specified assessment conditions and which is used to mitigate against very remote events

NL

3.1

NOTE

te

The probability of abnormal assessment situations is indicated as “10-4 per annum or lower”. This is not consistent with the definitions of “abnormal events/values” in ISO 19901-1 and 19902, where they are given as typically 10-3 to 10-4 per annum, while extreme values are defined as being of the order of 10-2 per annum. (NB: So far only ISO 19903 uses “10-4 per annum or lower”).

Bring in line with ISO 19901-1 and 19902.

NL

3.3

ed

The definition is modelled after ISO 19902, replacing “design” by “assessment”. Following the practice used in ISO 19901-7 and 19904-1, a NOTE should be added giving a reference to their basis (the source).

Add:

NOTE Adapted from ISO 19902:200x, definition 3.2.(200x is likely to be 2007)

NL

3.4

ed

As for 3.2.

Add:

NOTE Adapted from ISO 19902:200x, definition 3.3.

NL

3.4 and 3.5

ed

These are out of alphabetical order.

Swap sequence of 3.4 and 3.5.

NL

3.5

NOTE 2

te/ed

Include these observations/discussion in an appropriate place in the regular text of the document (e.g. Clause 7), not in a NOTE with the definition.

Relocate the contents of the NOTE to e.g. Clause 7.

NL

3.10

te/ed

The text is not consistent with definition in ISO 19900.

Change to:

assessment situation

the set of physical conditions representing real conditions during a certain time interval for which the assessment is intended to demonstrate that the acceptance criteria of this document for relevant limit states are not exceeded

NOTE Adapted from ISO 19900:2002, definition 2.13.

NL

3.11

ed

Add NOTE giving the source.

Add:

NOTE Adapted from ISO 19902:2002, definition 2.14.

NL

3.15

te/ed

Use consistent terminology.

Change “combined load” to “combined actions”.

NL

3.17

te/ed

This refers to the notion of a “basic variable”; we recommend to add this term.

Add:

basic variable

one of a specified set of variables representing physical quantities which characterize actions, environmental influences, geometrical quantities, or material properties including soil properties

[ISO 19900:2002]

NL

3.20

te/ed

Delete the article and be specific about failure of what.

Make definition consistent with the definition in ISO 19902 (see FDIS) by deleting equal sign and changing “and” to “and/or”.

Change to:

consequence category

classification system for identifying the environmental, economic and indirect personnel safety consequences of failure of a jack-up

NOTE Categories for environmental and economic consequences are (see 5.3.3):

C1 high environmental and/or economic consequence

C2 medium environmental and/or economic consequence

C3 low environmental and economic consequence

NOTEAdapted from ISO 19902:200x, definition 3.11.

NL

3.21

te/ed

For consistency within the 19900 series of standards we recommend to change to the notion of “recognized classification society”, as defined in ISO 19901-7 and/or 19904-1, if necessary with an adapted definition.

Use (adapted?) definition from ISO 19901-7 or 19904-1.

NL

3.23 and 3.100

te/ed

The counterpart of “deterministic” is “probabilistic”, while “stochastic” is not really synonymous with “probabilistic”. Precise definitions of “deterministic” and “stochastic” are not easy to give, while we think that all engineers in the industry are broadly familiar with their meaning. We suggest that both definitions are best deleted.

If 3.100 - stochastic analysis is maintained we propose to add a NOTE as shown in the next column.

Delete 3.23 and 3.100.

NOTE In general, a linear(ized) stochastic analysis can be performed in the frequency domain or in the time domain; non-linear stochastic analysis can only be performed by time domain simulations. This document does not support frequency domain stochastic analysis.

NL

3.24

NOTE

te/ed

Consistency of terminology: use “actions” instead of “loads”.

The NOTE differs from ISO 19902; move the source indicator therefore to a position above the NOTE.

Change to:

dynamic amplification factor

DAF

ratio of a dynamic action effect to the corresponding static action effect

[ISO 19902:200x]

NOTE For a jack-up the dynamic action effect is best simulated by means of a concentrated or distributed inertial loadset. It is usually not appropriate to factor the static environmental actions to simulate the effects of dynamic actions.

NL

3.25 and 3.26

te/ed

Wrong font and use of wrong term.

DAFS and DAFR are special forms of DAF in 3.24. Repeating the NOTE is superfluous.

1) The definitions should be in regular font, not bold.

2) replace the last words “mean effect” by “mean value”

3) delete the NOTES

NL

3.28

te/ed

Make definition identical with ISO 19902.

Change to:

exposure level

classification system used to define the requirements for a structure based on consideration of life-safety and of environmental and economic consequences of failure

[ISO 19902:200x]

NOTE An exposure level 1 (L1) jack-up is the most critical and exposure level 3 (L3) the least.

NL

3.33

te/ed

Consistency of terminology.

Change “subjected to loading” to “subjected to actions”

NL

3.36

te/ed

Add the NOTE from ISO 19902

Add:

NOTEWhen a global analysis is of a transient situation (e.g. seismic) the inertial response is part of the equilibrium.

NL

3.43

te/ed

Improved clarity.

Change to:

intrinsic wave frequency

wave frequency of a periodic wave in a reference frame that is stationary with respect to the wave, i.e. with no current present

NL

3.44

NOTE

ed

Seabed contains the bearing strata; sea floor is the interface between the water column and the seabed.

Change “sea floor” into “seabed” (2x).

NL

3.45

ed

Plural/singular error and consistency of terminology.

Change “…. produces the load level …” into “……... produce the action level ….”.

NL

3.46

te/ed


Change “ … increase of foundation load …” into “… increase of actions on the foundation …”.

NL

3.49

ed

Be more specific.

Make definition consistent with the definition in ISO 19902 (see FDIS) by deleting the equal sign. Correct spelling.

Change to:

life-safety category

classification system for identifying the applicable level of life-safety of personnel on a jack-up:

NOTE 1Categories for life-safety are (see 5.5.2):

S1 manned non-evacuated

S2 manned-evacuated

S3 unmanned

NOTE 2Adapted from ISO 19902:200x, definition 3.27.

NL

3.50

NOTE

ed

Formulation of NOTE.

Change to:

NOTEAdapted from ISO 19900:2002, definition 2.21.

NL

3.52

reference

ed

Wrong source

Change “[ISO 19900:2002]” into “[ISO 19902:200x]”

NL

3.53

te/ed

Make consistent with definition in ISO 19902.

Change to:

load case

compatible set of load arrangements, sets of deformations and imperfections considered simultaneously with permanent actions and fixed variable actions for a particular assessment or verification

NOTEAdapted from ISO 19902:200x, definition 3.29.

NL

3.63

te/ed

The addition “over a defined period of time (e.g. x hours)” to the definition in ISO 19901-1 is unnecessary. Make the definition identical to that in ISO 19901-1.

Delete “…. over a defined period of time (e.g. X hours)”

NL

3.64

te/ed

This definition of “nominal strength” is modelled after the definition of “nominal stress” in ISO 19902. If considered necessary we recommend some changes to the formulation.

The definition of “nominal stress” should also be included as this term is referred to in 3.101 (SCF); see further down.

Change to:

nominal strength

strength calculated for a cross-sectional area, taking into acccount the stress raising effects of the macro-geometrical shape of the component of which the section forms a part, but disregarding the local stress raising effects from the section shape and any weldment or other fixing detail

]NOTEAdapted from ISO 19902:200x, definition 3.34.

NL

3.69

te

Permanent action (not load!!) is one of several types of actions, which are all defined in ISO 19900, Clause 6. These apply to all standards of the 19900 series. They are not redefined in any other ISO 19900 standard; do not do this in 19905-1 either. See also 3.107.

Delete definition.

NL

3.70

te

Do not change the definition from the one given in ISO 19901-1!

It is alphabetically out of order.

Adopt definition from ISO 19901-1.

Move it to a place between current 394 and 3.95.

NL

3.71

ed

Bring in line with 3.15 and change of a preposition.

Change to:

preloading

vertical load test on a jack-up leg to ensure sufficient foundation bearing capacity under assessment conditions

US2

3.71 3.72

Page 2

Rapid Leg Penetration should be added as a term since it is different than a punch through condition

NL

3.72

ed

Improved clarity.

Change to:

punch-through

rapid uncontrolled vertical leg movement due to soil failure in strong soil overlying weak soil

NL

3.73

te/ed

Replace entry by the definition in ISO 19902 (see FDIS).

Replace by definition in ISO 19902.

NL

3.75

te/ed

The definition refers to “non-critical components” (highlighted in yellow). This hinges on also defining “critical component”, which is indeed done in ISO 19902. We recommend adding definition of “critical component” (see ISO FDIS 19902, def. 3.12).

Add definition of “critical component” from ISO 19902.

NL

3.76

line 2

ed

Adopt definition from ISO 19902.

Change “…. territorial waters …” into “… jurisdiction ……”

NL

3.78

te/ed

Adopt definition from ISO 19902.

Replace (identically) by definition from ISO 19902.

NL

3.79

te/ed

1) The word “capacity” is used here in its normal language (dictionary) sense, which would be fully acceptable. If in doubt or wishing to avoid the word, then replace it with “capability”.

2) The added part “with the unfactored assessment loading” compared to the definition in ISO 19902 is inappropriate as the reference level can vary from one case to the next; delete this part.

Change to:

measure of the capability of a structural system to withstand overload

NOTE 2Note 1 is adapted from ISO 19902:200x, definition 3.45.

NL

3.81

NOTE & source

ed

A.5.8 is a subclause.The definition of scatter diagram is exactly the definition from ISO 19901-1.

Change “Clause A.5.8” to “subclause A.5.8”.Delete the word “After”: [ISO 19901-1:2005]

NL

3.83

te/ed

Inconsistency: the term is “sea floor instability”, whereas the definition refers to “instability of the seabed”. The correct term should be seabed instability.Also, we doubt this definition is necessary.

Change term from “sea floor instability” to “seabed instability”, or delete 3.58 altogether.

NL

3.88

NOTE

ed

line 2: the subscript of the parameter m0 is a zero, not a letter o.

line 3: “Clause 3.31” is wrong formulation.

Change “mo” to “m0” (2x).

Change “Clause 3.31” to “definition 3.31”.

NL

3.90

ed

Misspelling.

Change “jackup” to “jack-up”.

NL

3.91

te/ed

Use “spudcan”, which is a defined term, instead of “footing”.

It is our impression that use of the term “footing” has been discontinued and was replaced by the term “spudcan”. However, “footing” still appears in several places in the text.

Change “footing” to “spudcan”.

Review whole document for occurrence of “footing” and adjust use of the term as necessary.

US2

3.91, 3.92

Page 12

Is this referencing a mat type supported rig?

NL

3.93

te/ed


Is this definition necessary? The term “shielding” appears in the NOTE. If “solidification” is included, then “shielding” should also be included. In no other standard of the ISO 19900 series these terms are defined.

Change “wave forces” to “actions from waves”,or delete 3.93 altogether.

NL

3.101

te/ed

The term “nominal stress” appears in the definition. This term should also be defined; see ISO 19902 definition 3.34. (see also comment on 3.64 - nominal strength)

Add definition of “nominal stress”.

NL

3.102

ed

The definition here is identical to the definition in ISO 19902.

Delete the observation “Check for changes in final version.”

NL

3.103

definition and NOTE

te/ed

A component can consist of parts with a different configuration and/or from a different material (e.g. reinforcement such as ring stiffeners, gusset plates) and can still be dealt with as one component. We see no need to go to the level of detail apparently envisaged here by deviating from the definition given in ISO 19902.

We suggest to reconsider the terminology and adjust the whole document in accordance with the adopted term(s).

Change to definition as in ISO 19902:

“physically distinguishable part of a structure”

[ISO 19902:200x]

and reformulate or delete the NOTE.

NL

3.104

te

Keep the definition the same as in ISO 19901-1.

Change to:

sustained wind speed

time averaged wind speed with a defined averaging duration of 10 min or longer

[ISO 19901-1: 2005]

NL

3.105

te/ed

Accept the definition from ISO 19904-1 as it stands; do not ‘improve’ or reword it.

Keep definition from ISO 19901-4 unchanged.

NL

3.106

te/ed

Are assessments without exception always made at the force level? We suggest to maintain flexibility by keeping the formulation as ‘stress’ or ‘force’, as given in ISO 19902.

Utilizations are as a matter of course always dealing with action effects due to factored actions. The action effects can be expressed in stress terms, in force terms or in something else.

Change the term “assessment force” in the definition and in NOTES 3 and 5 to:

- “assessment stress (force)”. and

- “assessment resistance in force units” to “assessment resistance in stress (force) units”.

Correct text in line 2 of NOTE 5 to:

“….reduced to an inequality of the form …”

Change source to:

“NOTEAdapted from ISO 19902:200x, definition 3.57.

NL

3.107

te

Variable action (not load!!) is one of several types of actions, which are all defined in ISO 19900, Clause 6. These apply to all standards of the 19900 series. They are not redefined in any other ISO 19900 standard; neither do this in 19905-1. See also 3.69.

Delete definition.

NL

3.108

te/ed

Add all or most of NOTE 2 from ISO 19901-1.

Add source of definition.

Add NOTE 2 from ISO 19901-1, as it is or adjusted.

Add:

NOTE 3 Adjusted from ISO 19901-1:2005, definition 3.41.

CA

4

Abbreviations Terms

ed

SNAME

Should be added to Abbreviated Terms

US2

4

Page 15

Suggest adding LAT and MLLW as definitions defining water depth references

NL

4.1

te/ed

- ALS is the accidental limit state (not accidental damage limit state);

- MOU does not appear in the document (other than in this list);

- The definitions of DAFS and DAFR are not consistent with 3.25 and 3.26, respectively.

- ALS and FLS are listed twice.

- use UK spelling in PSIIP

- ALS: delete the word “damage”;

- delete MOU;

- Make definitions of DAFS and DAFR consistent;

- Remove 2nd entries of ALS and FLS;

- Change “program” to “programme”.

NL

4.1

ed

Several abbreviations appearing in the document are currently not included in 4.1. They should either be added or use of these abbreviations should be avoided.

Not currently included are:

BOP

BSTF

FE [generally FEA is used, e.g. in 19902]

LRFD

MHWS [not in ISO 19901-1, suggest to avoid]

MLWS [not in ISO 19901-1, suggest to avoid]

MPM

MPME

OCR

PDF

ROV

SDOF

WSD

NL

4.2

te/ed

Use of symbols should be decided and rationalized. Do not let this wait till the end, as a last resort type of activity.

Do not use different symbols per clause. FDIS 19902 can perhaps be used as an example; main symbols used throughout the document are collected and defined at the front; more specific symbols are defined locally where they are used.

Ensure that symbols are well defined and consistently used in normative as well as the annexes.

As far as practically possible they should further correspond with the ISO recommended symbols and be collected as per ISO Directives.

US2

4.9

Page 58

m shows 3 different definitions

NL

5.1 and 5.2

ed

Proposed editorial improvements.


NL

5.2

Figure 5.2-1

te

The figure needs to be updated to include comments provided earlier, as well as any revisions to reflect the latest version of the document.

In our opinion the figure should stay in the main body (the normative) part of the document. It fits logically in 5.2.

NL

5.3

a)

te/ed

· suggest reformulation of 1st line for clarity;

-”metocean actions” is unfortunate phrasing; these are normally called “environmental actions”

· NOTES are purely informative and may not contain requirements or recommendations according to ISO Directives. Convert the NOTE to normal text and reformulate slightly to conform.

Change to:

The site-specific assessment shall include evaluation of the ULS for assessment situations including extreme combinations of environmental actions and laoding configuration (level of variable actions, ……..”

In benign areas the ULS environment is sometimes within the defined SLS limits for the jack-up. In such cases the assessment should be made for the ULS environment and the proposed operating configurations. This is because the environmental conditions will not exceed the limits for changing to the elevated storm mode.

NL

5.3

b), c) and d)

te/ed

Use plural forms for limit states.

Use SLSs, FLSs and ALSs.

NL

5.3

d) heading

ed

Do not deviate from the defined term.

Delete the word “damage”: Accidental limit states (ALS).

NL

5.3

para 1

te/ed

Better to remove reference to specific (sub)clauses in external documents.

The 2nd sentence is confusing; does it contain a contradiction?

Change to:

“ISO 19900 divides …”

Reformulate the 2nd sentence.

NL

5.4.1

NOTE

te/ed

The NOTE is part of the normal text.

Also suggest deleting the word ‘initial’ from line 1.

Further, any deviations will require buy-in from all stakeholders.

Convert the NOTE to normal text.

Delete the word “initial”.

Ad at the end: “…… communicated to the personnel operating the jack-up and other stakeholders.”

UK

5.4.1

NOTE

te/ed

Any deviations will require buy-in from all stakeholders

After “personnel operating the jack-up”Add text “and other stakeholders”

US1

5.4.1

NOTE

te/ed

Any deviations will require buy-in from all stakeholders

After “personnel operating the jack-up”Add text “and other stakeholders”

NL

5.4.2

ed

The word “clearly” is unnecessary and we propose to delete it.

Delete “clearly” (twice).

NL

5.4.3

te/ed

Use “extreme storm event”, which is a defined term.

Use sharper formulation.

Change to:

5.4.3 Extreme storm event approach angle

The extreme storm event approach angles relative to the jack-up are usually different for the various checks that shall be made (e.g. strength vs. overturning checks). The critical direction for each check shall be used.

NL

5.4.4

ed

· Consistency: the terminology used is “elevated storm mode”.

· Line 3: the word: “therefore” is unnecessary, if not inappropriate, and best deleted.

· Consistency of terminology.

· Change to: “elevated storm mode” (twice);

· delete “therefore”.

· Change to: “variable actions”.

NL

5.4.7

te/ed

Use sharper formulation, and at the end identify the items at risk more clearly.

Change to:

Where necessary the interaction of the jack-up with any adjacent structures shall be considered. Aspects to be included in the site-specific assessment are the effects of the jack-up's spudcans on the foundation of the adjacent structure, and the effects of relative motions between the jack-up and the adjacent structure on , well casing, drilling equipment and well surface equipment (risers, connectors, flanges, etc.).

UK

5.4.7

te/ed

Identify risk more clearly

Replace “drill-string, well conductor, well conductor guides, etc.”With “well casings, drilling equipment and well surface equipment (risers, connectors, flanges, etc) “

US1

5.4.7

te/ed

Identify risk more clearly

Replace “drill-string, well conductor, well conductor guides, etc.”With “well casings, drilling equipment and well surface equipment (risers, connectors, flanges, etc) “

NL

5.4.8

te/ed

Improve formulation.

Change to:

The assessor should be aware that the characteristics of certain designs can have impacts on the site-specific assessment that are not specifically addressed in this document. In such cases the validity of the assessment as made shall be confirmed once the unit has been installed.

For example, high bending moments in the legs can be caused by lateral displacement of the spudcan or by eccentric vertical spudcan reaction due to footprints or other seabed features.

NOTE The RPD usually is a good indicator of the degree of eccentricity and the acceptability of these action effects when elevated.

NL

5.5

ed

Proposed editorial changes for conformity with ISO 19902 (with adjustments) and consistency of terminology.


NL

5.5.2

b), 2nd sentence

te

This is a requirement.

Change “may” to “shall”.

NL

5.5.2

c)

te

Item 1) from the text in ISO 19902 has been left out. We see absolutely no reason for this exclusion and want to reinsert it.


NL

5.5.3

1st bullet point and NOTE

te

The consequence category includes risk of loss of life, for people other than the jack-up’s own complement. The (adjusted) 1st bullet point expresses this. The NOTE also requires adjustment to suit, and to express that it is not only the operator who sets the consequence category; all stakeholders should agree to this.


NL

5.5.3

a) and b)

te

A release does not relate only to oil, but also to gas.

Change “oil” to “hydrocarbons” (several times); see accompanying Word document

NL

5.5.3

c), last sentence

te

This is a requirement.

Change “may” to “shall”.

UK

5.5.3

NOTE

te/ed

All stakeholders to agree

Replace “Operator will drive”With “all stakeholders will agree”

US1

5.5.3

NOTE

te/ed

All stakeholders to agree

Replace “Operator will drive”With “all stakeholders will agree”

NL

5.5.4

Table 5.5-1

te

The Table categories are in conflict with the basic premise formulated in the 2nd sentence of para 1. This principle applies to all structures under the ISO 19900 series (see ISO 19902, 19903, 1904-1). It also applies to jack-ups.

Change exposure levels in accordance with 1st paragraph of this subclause.

NL

5.5.4

text underneath table

te

The partial action and resistance factors, and associated assessment criteria are not yet provided and must be reviewed when finalized.

NL

6

ed

Proposed editorial improvements. Several of these proposals were given earlier.


NL

6.3

te

This subclause assumes jack-up placement at an open water location, which then allows hull elevation to be set to achieve adequate air gap. However, it should also address interactions with a platform when placed alongside. Add text describing platform interface challenges, such as ability to reach slot positions and clearance between cantilever and weather deck for well equipment stack.

See accompanying Word document for improvements to the existing text.

Add text to describe interface data with the platform (structure and topsides, risers, pipelines, umbilicals, slot positions, well surface equipment, etc.), with particular reference to implications for the required cantilever positions and proximity of the jack-up to the adjacent infrastructure.

UK

6.3

te/ed

This section assumes an open location which then allows jack-up to set hull elevation to achieve air gap. Brief text describing platform interface challenge (e.g. slot location, or cantilever to clear weather deck by x metres to achieve well equipment stack) is required.

Interface data are required (substructure, topsides, risers, pipelines, umbilicals, slot position, well surface equipment, etc) with particular reference to required cantilever positions and proximity of jack-up to adjacent infrastructure.

US1

6.3

te/ed

This section assumes an open location which then allows jack-up to set hull elevation to achieve air gap. Brief text describing platform interface challenge (e.g. slot location, or cantilever to clear weather deck by x metres to achieve well equipment stack) is required.

Interface data are required (substructure, topsides, risers, pipelines, umbilicals, slot position, well surface equipment, etc) with particular reference to required cantilever positions and proximity of jack-up to adjacent infrastructure.

NL

6.4

te/ed

Make sure that the ‘shopping list’ to be added includes wave crest elevation as a key parameter.

UK

6.4

te/ed

Wave crest elevation is a key parameter for matching a jack-up to a proposed location

Include in the “shopping list”

”wave crest elevation”

US1

6.4

te/ed

Wave crest elevation is a key parameter for matching a jack-up to a proposed location

Include in the “shopping list”

”wave crest elevation”

US2

6.5

Page 24

Caution might be stated here in proposing taking soil borings from a JU rig before preloading especially in areas where crusts might have occurred as well as where paleo channels may exist. Prior geohazards survey should be a prerequisite before making this call.

US2

6.5

Page 24

Modifications may be required to the rig in order to take soil borings prior to skidding out.

NL

6.5

para 4, line 2

te/ed

Is “are recommended” strong enough?

Suggest change to “should be carried out”.

NL

7

ed



NL

7.2

b) 1)

ed

Consistency.

Change “Permanent loads” to “Permanent actions”.

NL

7.2

c) 2)

te/ed

The indirect actions resulting from dynamic response are accelerations; see also 7.6

Change “Dynamic effects” to “Accelerations from dynamic response.”

NL

7.2 and other locations, also in Annex A

a)

te/ed

“metocean actions” is unfortunate phrasing; these actions are usually called “environmental actions”. Alternatively, one could use something like “actions due to metocean conditions” if the specific source of the actions needs to be emphasized. However, in our opinion this is not necessary and we prefer the former solution. See also comment on 5.3 a).

Change consistently to “environmental actions”.

NL

7.3.1.1

a), 2nd para

te

The environmental actions in a joint probability model are due to the 100 year wave with an associated current on the under water part of the jack-up plus the 100 year wind action on the above water part of the jack-up. For the wind action the use of 100 year 1 hour mean wind is not acceptable.

Remove the part within brackets: “(typically this wind speed may be taken conservatively [?!] as the 1 hour mean 100 year return period individual extreme wind)” and give clear guidance on what extreme wind speed should be used.

NL

7.3.4

1st sentence

ed

The 1st sentence is incomplete; it is just a fragment.

Change to:Wind actions shall be computed using wind velocity, wind profile and exposed areas.

NL

7.6

ed

Dynamic response results in accelerations and inertial effects; these are all ‘action effects’. The accelerations are the indirect actions (see 3.5); we propose using “inertial forces” (not ‘actions’, which are externally applied (see 3.5) but ‘forces’ as they are an action effect). See also comment at the beginning (before comment on the introduction).

Change “Indirect actions” to “Inertial forces”.

NL

7.7

te/ed

Include reference to 8.8.8, in addition to 10.7.

Change to “… appropriate, see 8.8.8 and 10.7.”

NL

8

ed



NL

8.8.1

te

If all partial action factors are included in the normative Annex B they should not be duplicated here.

See comment on Annex B for the values of certain factors.

Replace factors with a cross-reference to Annex B.

NL

8.8.2

title

te/ed

Maintain terminology and classification of actions from ISO 19900, which applies to all offshore structures.

Change to:

8.8.2 Permanent and variable actions

See further accompanying Word document.

NL

8.8.5

te/ed

Inertial effects are action responses, hence “forces” instead of “actions”; see 7.6 above.

[Apologies if comments/modifications to an earlier draft in 2005 have in some cases caused possible confusion.]


NL

8.8.8

te/ed

Rephrase as shown in column 6.

Change to:

Earthquake actions shall include global accelerations due to fundamental modes of vibration in addition to local actions from soil movement on the spudcans and the legs where relevant. The associated inertial forces on all significant masses shall be taken into account.

NL

9

ed


see accompanying Word document for whole Clause 9.

CA

9 and A9

(Foundations)

ge, te

The document, including the Annex, is in some cases incomplete in respective of the foundations. There are inserts such as:

“Add brief précis of the informative with some shalls..” (p34)

“reduction for backfill – to be addressed by Templeton” (p35)

“Randolph to check …..and decide path forward..” (p 112)

“GVDZ and ETRD to discuss and recommend….”(p 118)

“Suggest R Dean and R Overy tackle this” (p120)

“Guy is uneasy about f1 and f2” (p 122)

“We use the same for sand & clay – should we? (p 125)

“Guy is uneasy about f1 and f2” (p 125)

“Text required to address plasticity approach” (p 126)

“Reword this para; more to follow…… (p 129)

“Bearing and sliding equations to be inserted” (p 130)

The overall appearance is that this is still a “work in progress”. While it is admirable to obtain the most advanced R&D analysis and experimental data, a Standard is of necessity a consensus document that reflects both regulatory, practice and academic views. It is not clear that such a consensus exists. It is also not clear what work has been done to ensure that the recommendations included in the draft compare reasonably with current practice and experience (although we do not want prevent technical advances, we should at least be aware of what the differences are).

Also, it is not appropriate to comment or “approve” an incomplete Standard.

The following path forward is recommended:

1) Proceed with the Normative, maybe editing somewhat so that it is a performance standard that everyone can agree to.

2) Carry out studies to show how the proposed foundation recommendations compare with existing codes and practice in different parts of the world, including the latest R&D (centrifuge tests, numerical, analytical, etc.) (This may be called “calibration studies”, but it could be more than that)

3) Revisit Annex / Information when a consensus amongst the working group has been achieved.

NL

9.1

te/ed

There is a difference between “bearing” and “resistance”; see 9.3.6.


NL

9.2

te/ed

There is a difference between “actions” and “forces” see 9.3; for “footing” see 3.91.


NL

9.2

te

Prediction of leg penetration is a key parameter for the rig move operation and needs to be added to the list as a separate item.


UK

9.2

te/ed

This section needs to take the opportunity to highlight leg penetration prediction as a separate line item, as this is a key parameter during the rig move operation.

Above first bullet point “ The possibility of punch through”

Add” Leg penetration prediction”

US1

9.2

te/ed

This section needs to take the opportunity to highlight leg penetration prediction as a separate line item, as this is a key parameter during the rig move operation.

Above first bullet point “ The possibility of punch through”

Add” Leg penetration prediction”

US2

9.2

Page

In some areas, COP has embarked on a geotechnical investigation where both borings and in situ testing were performed in each spud can prior to the arrival of the JU rig.

US2

9.2

Page 32,33

The statement of suggesting that “Applicable information from previous operations may be used” should be qualified. We have seen that crustal layer depths vary over a field as well as from leg to leg so one needs to insure that this is not taken lightly.

US2

9.2

Page 33

Assessment should include rapid leg penetration which is different than a punch through situation

NL

9.3

te/ed

Reactions from the seabed on the spudcan are action effects and therefore spudcan forces; soil forces are also action effects and internal to the soil.

The following paragraph quoted from the introduction to ISO 19901-4 explains the situation further:” For an offshore structure and its foundations, the action effects at the interface between the structure's subsystem and the foundation's subsystem(s) are internal forces, moments and deformations. When addressing the foundation's subsystem(s) in isolation, these internal forces, moments and deformations may be considered as actions on the foundation's subsystem(s) and this approach is followed in this part of ISO 19901.”


UK

9.3.2

te/ed

Make link between theory and practice

At end of 9.3.2 Add” The use of this data during rig move operations provides essential information on the continuity between theoretical assessment and operational reality.”

US1

9.3.2

te/ed

Make link between theory and practice

At end of 9.3.2 Add” The use of this data during rig move operations provides essential information on the continuity between theoretical assessment and operational reality.”

US2

9.3.2

Page 34

What is meant by “ a lower preload may be acceptable when justified by appropriate geotechnical considerations”?

NL

9.3.2

para 1

te

The factoring is not applied to the “soil loading” but to the actions applied on the jack-up!!

Furthermore, use should be made of the opportunity to link theory and practice.


CA

9.3.3, 9.3.4

ge

Clause is absent, with comment that a brief précis from the Informative to be added. Cannot approve something that is absent.

N/A

CA

9.3.4

All

ge

In this section there are statements such as: “The shear modulus for clay and sand shall be determined in accordance with A9.3.4.3 or A.9.3.4.4”. This in effect results in the Informative part becoming part of the standard.

Delete the sentences stipulating that equations in Informative sections be used. It is anyway obvious that further information is provided in the Informative part, so there is no need to even say “Guidance is provided…..”

CA

9.3.5

Last sentence of paragraph

ge

Sentence mandates a clause in Informative part

Delete last sentence

US2

9.3.5

Page 34

Please define or provide an illustration as to vertical-horizontal capacity envelopes

NL

9.3.6

te

The general term for what can be withstood is “resistance”; in the 19900 series resistance of structural components is referred to as “strength” while resistance of foundations is referred to as “capacity. However, “bearing capacity” of a foundation refers (predominantly) to vertical capacity; for sliding the general term “resistance” is used: hence “sliding resistance”; for consistency with ISO 19901-4.


FR

9.3.7

te

Add “Resistance to penetration and retrieval”

US2

9.3.7

Page 35

Is this section mainly referring to mat foundations but calling them spud cans as well? Possible a schematic would be helpful here to better familiarise the reader with exactly what is being discussed.

NL

9.4.3 and 9.4.7

ed

Include References in the informative annex A. and replace them by referring to A.9.4.3 and A.9.4.7.

FR

9.4.4

te

Add “in particular for skirted spudcans in cohesive soils”

CA

9.4.5

First para, title

te

There is not general agreement about the definition, or even mechanics of “liquefaction” and “cyclic mobility”, so a description in this Standard is not called for.

Change to: 9.4.5. Cyclic Loading

Cyclic loads, from earthquakes or severe storms, may cause a progressive buildup of pore pressures within foundation soils. Depending on the extent of pore pressure developed, foundation failure may result. The design shall consider the effects of cyclic loading on stability.

FR

9.4.6

te

To precise if “continued foundation settlement” mean “continuous jack-up leg penetration”

CA

9.4.7

5th para, “There is no….”

te

This paragraph states that there is no definitive procedure, but gives useful references. This is appropriate material for Informative section.

Delete, and move to Informative.

NL

9.4.9

te/ed

Proximity is “closeness”; greater proximity etc. is therefore confusing: it could be interpreted as being closer instead of being farther away, as intended here. Use “distance” instead of “proximity”.


CA

9.4.9

2nd para

ge

States that guidance is given in Annex. This is an unnecessary statement

Delete

CA

9.4.9

Last sentence of 1st para

ge

“…. Owner may wish to consider…” is more appropriate in Informative.

Suggest “When proximity is closer than one spudcan diameter or layered soils conditions are encountered, the consequences of induced pile loading should be considered.”

US2

9.4.10

Page 38

Please add a section on Swiss Cheesing Techniques

NL

10

ed


see accompanying Word document.

NL

10 and A.10

throughout

te/ed

Response is a general term meaning generally the same as action effect. Response can be used in singular and in plural. However, in most situations ‘response’ and ‘action effect’ both relate to many different variables and the plural forms should be used. The singular form would only be appropriate for a generic description (such as static or dynamic response) or when referring to a specific variable.

Review text for appropriate plural forms.

NL

10.1

last line

ed

Remove 3rd word.

Change to “actions are addressed in Clause 8.”

NL

10.5.3

para 1

te

line 2: plural.

last sentence: Don’t understand this: one simulation provides only one maximum value of a particular variable; that does not provide the necessary information for determining the most probable maximum.

Change to “multiple realizations”

reword or clarify.

NL

10.5.4

line 1

line 4

te/ed

te

‘moments in plural (e.g. in two planes) and correction.

The applied actions are factored, not the vertical reaction. Reactions are action effects (the results) of the factored actions.

Change to:

“The leg moments due to initial leg inclination shall be combined with member forces from “

Correct phrasing.

NL

10.7

te

There are several important comments on subclause 10.7.

1) Seismic risk assessment should be based on the site seismic zone and the seismic risk category (SRC), see ISO 19901-2. The SRC determines if a simplified or a detailed procedure is required.

2) An ULS assessment is associated with an ELE (not an ALE). Due to the ELE little or no damage shall be sustained. For this the maps in ISO 19901-2, Annex B, may be used, which are based on a 1000 year return period.

3) For exposure level L1 the target annual probability of failure corresponds with a return period of 2500 years.

Also, Include reference to 8.6.3 for foundation modelling under earthquake excitation.

Revise the text to bring 10.7 in line with ISO 19901-2.

For some preliminary editorial suggestions, see accompanying Word document.

UK

10.7

te/ed

Whilst understanding the objective of identifying an onerous assessment as a method of swiftly proving the jack-ups robustness under seismic loading, is the 1000 year ALE appropriate?

For L1 exposure level, ISO 19901-2 Seismic Design procedures & criteria gives a 2500 year return period for an Abnormal Level Earthquake [ALE]

Replace 1000 with 2500

US1

10.7

te/ed

Whilst understanding the objective of identifying an onerous assessment as a method of swiftly proving the jack-ups robustness under seismic loading, is the 1000 year ALE appropriate?

For L1 exposure level, ISO 19901-2 Seismic Design procedures & criteria gives a 2500 year return period for an Abnormal Level Earthquake [ALE]

Replace 1000 with 2500

UK

10.7

NOTE

te/ed

Seismic energy is usually at frequencies significantly different from a jack-ups lateral modes of vibration, but may achieve resonance with a jack-ups vertical modes of vibration, the drilling derrick and ancillary equipment ( pipe stands etc)

Replace “or due to lateral stability”

with

“or due to resonant response with the rig’s lateral or vertical modes of vibration. The effects of seismic loading on the drilling derrick and ancillary equipment (pipe stands etc) needs to be considered.

US1

10.7

NOTE

te/ed

Seismic energy is usually at frequencies significantly different from a jack-ups lateral modes of vibration, but may achieve resonance with a jack-ups vertical modes of vibration, the drilling derrick and ancillary equipment ( pipe stands etc)

Replace “or due to lateral stability”

with

“or due to resonant response with the rig’s lateral or vertical modes of vibration. The effects of seismic loading on the drilling derrick and ancillary equipment (pipe stands etc) needs to be considered.

NL

11

ed



NL

11.1

te/ed

- title: replace “scope” by “applicability”, as in earlier clauses;

- consistency of terminology (“special survey” is a defined term, without the word “classification”);

- according to ISO Directives a NOTE may not contain a recommendation; convert NOTE into regular text;

- replace “regulator” by all stakeholders (owner, operator or regulator); note that the defined term “regulator” includes CS.


NL

11.2

te/ed

- for welded structures only time-varying actions are relevant;

- “structural resistance” and “fatigue endurance” are specific to a (particular detail of a) structural component;

- the cross-reference to 11.3.1 does not add anything in the sense of “other data” and should be deleted as it is more restrictive than helpful;

- editorial improvements.


NL

11.3.1

te/ed

- fatigue is a highly local phenomenon associated with a particular location of a structural component; the fatigue life of a whole structure is not a meaningful concept;

- the margin of safety is related to criticality and inspectability, not to the planned duration on site;

- editorial improvements.


NL

11.3.2

te/ed

- “weight” is of no direct consequence for fatigue damage assessment of welded structures; it can only have an indirect effect through P-delta influence;

- we suggest to use “weight/mass” instead of “weight”; if this is not accepted, then “mass” alone is more appropriate;

- “otherwise” is not appropriate wording; the allowance does not come in place of monitoring (which covers past and present, not future), but is additional to this.


NL

12

ed



NL

12 and A.12

throughout

te/ed

Rationalize the nomenclature in accordance with the finally adopted terminology for parts / components / members; see 3.19 - 3.27 - 3.61 and 3.103.

Modify as required.

NL

12.1.3

ed

Move the reference to A.12.1.3 and include it in the Bibliography.

Follow ISO Directives.

NL

12.7

te/ed

The applied actions are factored, not the internal forces.


NL

13

ed



NL

13

throughout

te

This is a crucially important clause, which is currently not yet finalized, while guidance in A.13 is still completely missing. Combined with lack of completeness in other clauses and the missing informative annex this makes review and evaluation of 19905-1 unsatisfactory and near to impossible.

NL

13

throughout

te/ed

Make clear where all required partial action and resistance factors are given: are they distributed over various clauses or are they all collected in Annex B?

To avoid misunderstandings, be specific in cross-referencing applicable partial action and resistance factors.

NL

13.1.1

te

In the list of issues to be considered, the item on foundation integrity should include “leg penetration” (a key parameter for rig acceptability) and “sliding resistance” (which is different from bearing capacity).


UK

13.1.1

te/ed

Leg penetration is a key parameter for rig acceptability

Replace “ preload, bearing capacity”

with

“preload, leg penetration, bearing capacity”

US1

13.1.1

te/ed

Leg penetration is a key parameter for rig acceptability

Replace “ preload, bearing capacity”

with

“preload, leg penetration, bearing capacity”

NL

13.1.2

last para

te/ed

- replace “calculations” with “assessments”;

- “this standard” is an inappropriate formulation; if 19905-1 is meant then it should be “this document”; if 19905 in its totality is meant it should be “this International Standard” or even better “ISO 19905 parts 1 and 2”

Change to:

“... prior assessments according to …”

adjust as required.

NL

13.10

te/ed

This statement is in our opinion a requirement, which is expressed by “shall”.

Change “should” to “shall”.

NL

13.2

te/ed

This subclause needs technical as well as editorial improvements. Our comments relate to:

- there is no need to include here descriptions of the fundamentals of factoring; this is basic knowledge and also spelled out in the definition of utilization (3.106);

- checking for combined forces involves the application of an interaction equation, which does not correspond with the elementary form “action effect due to factored actions divided by factored resistance”; see again the definition of utilization in 3.106;

- there are several assessment situations to be checked; for each assessment situation the appropriate action effect(s), which are normally due to several applied and factored actions, need to be specified; the factors relevant to the case considered can vary from case to case; all this needs careful spelling out in an integral manner.

Rethink the general formulation of an assessment, making full use of and complying with definitions.

NL

13.3.1

te/ed

- as for Clause 12 and A.12: rationalize the nomenclature in accordance with the finally adopted terminology for parts / components / members; see 3.19 - 3.27 - 3.61 and 3.103;

- be specific in cross-referencing applicable partial action and resistance factors, and include these cross-references in normal text, not in an informative NOTE;

- the factors shall be normative, not informative (Annex B shall be normative).

Reformulate as necessary.

NL

13.3.2

te

Subclause still to be provided.

Provide the text.

NL

13.6

te/ed

- para 2: this is unclear and vague as written; the extreme wave crest height should be clearly defined in a definition or a (sub)clause; when done para 2 should be deleted as para 1 covers all;

- para 3: rephrase in a simpler and stricter manner as shown in column 6;

- 1st NOTE: the length of a wave crest is near to impossible to determine and should not be used as a condition or an additional criterion;

- 2nd NOTE: The definition of air gap in ISO 19900 as given below should be quoted as such rather than paraphrased:

”clearance between the highest water surface that occurs during the extreme environmental conditions and the lowest exposed part not designed to withstand wave impingement”.

- define “extreme wave crest” and delete para 2’

- change to “The hull elevation shall account for ……”

- delete the 1st NOTE.

- rephrase the 2nd NOTE.

NL

13.7

te

Leg length reserve should reflect any uncertainty in the prediction of leg penetration. The minimum value of 1,5 m is only applicable for locations where a high degree of certainty can be achieved.


UK

13.7

te/ed

A leg length reserve should reflect any uncertainty in the prediction of leg penetration, with the minimum value of 1,5m only applicable for locations where a high degree of certainty is achievable.

Replace 1st sentence with

The leg length reserve above the upper guides should reflect the uncertainty in the prediction of leg penetration and account for any settlement. A minimum value of 1.5 m may be applicable for locations where a high degree of certainty is achievable.

US1

13.7

te/ed

A leg length reserve should reflect any uncertainty in the prediction of leg penetration, with the minimum value of 1,5m only applicable for locations where a high degree of certainty is achievable.

Replace 1st sentence with

The leg length reserve above the upper guides should reflect the uncertainty in the prediction of leg penetration and account for any settlement. A minimum value of 1.5 m may be applicable for locations where a high degree of certainty is achievable.

NL

13.8

te/ed

- editorial suggestions;

- the cross-ref to the CoG position is incorrect; there is no specific subclause on CoG; 5.4.4 is the only one and discusses weight and CoG together;

- the partial resistance factor (R, OTM is solely intended to account for the uncertainty in determining the stabilizing moment; a factor of I,0 would suggest that there is no uncertainty involved, which is unrealistic. As far as we are aware a factor of 1,0 is neither supported by SNAME 5-5A rev. 2. A departure from partial resistance factors in the SNAME document requires justification.

- see accompanying Word document

- in view of its importance it should be ensured that the relevant position of the CoG is specified

- reconsider the value of (R, OTM

UK

13.8

te/ed

- the partial resistance factor (R, OTM of I,0 is not supported by SNAME 5-5A rev.2 Any departure from the partial resistance factors presented in that document requires justification.


US1

13.8

te/ed

- the partial resistance factor (R, OTM of I,0 is not supported by SNAME 5-5A rev.2 Any departure from the partial resistance factors presented in that document requires justification.


NL

13.9.1

2nd para

te

spudcan reactions are not factored; they are due to the application of factored actions

Change to “spudcan reactions due to factored actions”

see also accompanying Word document

US2

13.9.1

Page 54

Statements made pertaining to bearing capacity utilization are proposed to be checked. Not sure what is exactly being requested here with the “utilization” term. Also what are factored spud can reactions?

NL

13.9.2

line 1

te

same comment as for 13.9.1

Change to “reactions on any spudcan due to factored actions”

NL

Annex A

heading and NOTE

ed

- Use the ‘standard’ heading as in other 19900 documents;

- use phrasing of the NOTE as in other 19900 documents, e.g. as in FDIS 19902 or NOTE 1 of ISO 19904-1; it is worth considering copying all 5 NOTES in ISO 19904-1, giving clarification of the use of terminology in the document.

- Change heading to “Additional information and guidance”

- copy 5 NOTES from ISO 19904-1.

NL

Annex A

throughout

ed

Ensure that titles are identical with titles of corresponding (sub)clauses in the body of the document.

US2

A.4.9

Page 57

Both a and b are titled “bearing capacity squeezing factor” as well as f1 and f2 being referred to as “factor used in yield surface equation for embedded footings on clay”

NL

A.6.4

te/ed

Large parts of the contents of A.6.4 deal with actions and are consequently strongly related to A.7, where these parts would be better placed.

Bring most of A.6.4 over and integrate with A.7.

UK

A.6.4.1

2nd para

Strong preference for seasonal extremes not smaller all-year return periods, which may achieve same result, but is not sufficiently explicit as to the risk identification and management.

Reconsider the use of smaller return period extremes

US1

A.6.4.1

2nd para

Strong preference for seasonal extremes not smaller all-year return periods, which may achieve same result, but is not sufficiently explicit as to the risk identification and management.

Reconsider the use of smaller return period extremes

NL

A.6.4.2.3

te

Include appropriate text on the determination and application of extreme wave crest elevation for ensuring adequate air gap. A suggested reference for the North Sea is “A recommended approach for deriving ISO-compliant 10 000 year extreme water levels in the North Sea” by I.M. Leggett et al, OMAE 2007 - 29559.

Amend/complete as required.

UK

A.6.4.2.3

te/ed

For the North Sea, a suggested reference is

OMAE2007-29559 A RECOMMENDED APPROACH FOR DERIVING ISO-COMPLIANT 10,000 YEAR EXTREME WATER LEVELS IN THE NORTH SEA I M Leggett et al

Include text on the use and application of extreme wave crest calculation for ensuring sufficient air gap

UK

A.6.4.2.3

te/ed

The use of the 1-hour wind speed to approximate joint probability wind speed is not acceptable and shall be removed

Delete

” This wind speed may be conservatively taken as the 100 year return period individual extreme 1 hour mean wind << Review Panel query Jan 06 : IS THIS STILL ACCEPTED ?? “

US1

A.6.4.2.3

te/ed

For the North Sea, a suggested reference is

OMAE2007-29559 A RECOMMENDED APPROACH FOR DERIVING ISO-COMPLIANT 10,000 YEAR EXTREME WATER LEVELS IN THE NORTH SEA I M Leggett et al

Include text on the use and application of extreme wave crest calculation for ensuring sufficient air gap

US1

A.6.4.2.3

te/ed


Delete

” This wind speed may be conservatively taken as the 100 year return period individual extreme 1 hour mean wind << Review Panel query Jan 06 : IS THIS STILL ACCEPTED ?? “

NL

A.6.4.2.4

te/ed

Use information and data by preference from ISO 19901-1 instead of from the TR (19905-2). There are 2 reasons for this:- ISO 19901-1 is part of the ISO 19900 series and applies therefore to all offshore structures;- the standard is available now, while it could be quite a while before the TR is issued as ISO 19905-2.

Use ISO 19901-1 to the greatest extent possible.

NL

A.6.4.2.9

te/ed

A fatigue analysis for dynamically responding jack-ups should be performed using random waves and response, either in the frequency or in the time domain; see e.g. ISO 19902.

NL

A.6.4.4

te/ed

Consistency: use water depth(s) defined in ISO 19901-1; MHWS and MLWS do not appear in ISO 19901-1.

NL

A.6.4.6.1 and A.6.4.6.2

te

There is an inconsistency between para 2 of A.6.4.6.1, which refers to the logarithmic wind profile, and A.6.4.6.2 which gives a power law profile. (NB: if a power law profile is used the exponent is usually of the order of 1/8.5 rather than 1/10).

US2

A.6.5.1

Page 69

Even JU rigs with lower bearing pressures than previous used could still result in a punch through or rapid leg penetrations ?

US2

A.6.5.1

Table A6.5.1 Page 70, 71, 72

Add Swiss cheesing as one of the preventative measures for punch through

US2

A.6.5.1

Table A6.5.1 Page 70, 71, 72

Sliding failure – should this be qualified as mat type foundation so as to not confuse it with a an independent legged spud can?

US2

A.6.5.1.1

Page 69

Line spacing may be more dependent on water depth or overlap than just recommending a 100m line spacing and not qualifying a water depth?

FR

A.6.5.1.3

2nd para

ed

…with existing soil boring data in the vicinity and “showing” similar stratigraphy

US2

A.6.5.1.3

Page 69

Should different types of seismic equipment be mentions as to frequency and depth vs. accuracy?

FR

A.6.5.1.4.2

Last para

te

Delete “pressure-meter test” which is not a recognized test in offshore soil investigations

US2

A.6.5.1.4.2

Page 70

What is the definition of “transition zone”?

US2

A.6.5.1.4.2

Page 70

May want to mention that penetration calculations may be required during the course of the boring to insure that adequate depth is achieved

US2

A.6.5.1.4.2

Page 70

Suggesting that T-bar and/or pressure meter tests in the same sentence as PCPT and vane shear would infer that these are routine tests. It is hard enough to get drilling departments to pay for PCPT test let alone T-bar or pressure meter tests that most geotechnical vessel do not have or cannot operate in the first place.

US2

A.6.5.1.4.3

Page 70

Again, the statement of providing shear moduli and cyclic/dynamic behaviour needs to be better qualified than just a general statement suggesting that it may be required if soil strength may deteriorate under cyclic loading.

US2

A.6.5.1.4.3

Page 70

Unless specified beforehand (i.e. field program) performing consolidation tests are not routine procedure for JU rig investigation studies. Suggest you provide reasoning why OCR are required for this analysis and what benefit it may produce. Most drilling departments who might commission such a site investigation are not interested in research or other than an answer as to when and how long it will take to get the rig onsite and ready to spud the first well.

NL

A.7.3.1.1

te/ed

Rephrase “metocean actions”, “extreme metocean action model”, and similar phrases.

Change to “environmental action” and make use of the defined term “extreme storm event”.

UK

A.7.3.1.1

te/ed


Delete

”(typically this wind speed may be taken conservatively as the 1 hour mean 100-year return period individual extreme wind), “

US1

A.7.3.1.1

te/ed


Delete

”(typically this wind speed may be taken conservatively as the 1 hour mean 100-year return period individual extreme wind), “

NL

A.7.3.1.2

te

Mention that a stochastic analysis that should include non-linearities should be a time domain stochastic analysis.

NL

A.7.3.1.2

te

The hydrodynamic coefficients for deterministic and stochastic analysis should usually be chosen differently.

NL

A.7.3.2.4

ed

Consistency: use water depth(s) defined in ISO 19901-1; MWL does not appear in ISO 19901-1. See also comment on A.6.4.4.

NL

A.8.3-1

Figure A.8.3-1

ed

We do not support the panel suggestion to move the figure to the TR. The figure is a logical part of A.8 and we recommend to let it stay there.

NL

A.8.6.3

te/ed

Is “footings” in para 1 the correct term to use, or should it be replaced by “spudcans”? (see also comment to 3.91).

In para 2, make use of the defined term “extreme storm event” instead of “maximum storm” (leg moment).

Also in para 2, “loads” and “loading” on the spudcan or foundation are better replaced by “forces”; see the overall comments at the beginning of this table (before comment on the introduction) and comment on 9.3.

Adjust terminology as necessary.

NL

A.8.8

te/ed

Adjust terminology:

- throughout: use “action(s)” instead of “load(s)” and “loading”, except in “inertial forces” (A.8.8.5)- use “permanent and variable actions” instead of “self-weight and non-varying loads, variable and drilling loads” (A.8.8.1 a)) and instead of “self-weight and variable loads” (A.8.8.3).

Adjust terminology.

NL

A.9

te

Provisions for several items still need to be provided, while some other issues still need to be resolved.

Complete the provisions.

NL

A.9

throughout

te/ed

· Use correct terminology: verbal forms, appropriate and consistent terminology, phrasing, correct use of NOTES, etc.

· Introduce equation numbers.

· Introduce references as per the Directives and collect them in a Bibliography.

Follow ISO Directives and maintain consistency.

FR

A.9.3.2.2

6th para

te

Add “In areas with carbonate soils, the presence of a weakly cemented strata at or below mudline may involve additional uncertainties regarding the assessment of the punch-through risk”

US2

A.9.3.2.2

Page 111

Possibly a better word can be used in place of “crusts” to descried a layer of stronger soil resulting from a pause in preloading.

CA

A.9.3.2.3

3rd line after equation in 1st para

te

States preference to be given to strength data from unconsolidated undrained triaxial tests, miniature vane tests or torvane tests. The state of practice has moved beyond these tests, although it is recognized that much experience in GOM has been built-up on these tests, and there are much more reliable methods available. Preference should probably be given to in situ tests in the first instance.

Propose to replace with statement along the lines of: “Qualified geotechnical engineer to use most appropriate method to determine su.”

US2

A.9.3.2.3

Page 112

Include definition of terms here so reader does not have to refer back to pages 56-60 when describing an equation. It would also be useful to number each equation. May want to express second term as Gamma’ V where v is limited to the total volume of the spud can. Also need to propose over what depth that Su should be averaged? ( 0.09B below the level of the plate does not make sense.)

US2

A.9.3.2.3

Page 114

It would be most helpful to provide a schematic to better illustrate all the discussion on how Vlo is calculated and how Hcav is considered in the equation. The whole paragraph pertaining to backflow show be re-written to allow the reader a better understanding of what is being implied

US2

A.9.3.2.3

Page 114

Figure 9.3-5 is not shown even though it is referenced.

US2

A.9.3.2.3

Page 114

The last two sentences concerning NC clays and GOM seems out of place here. One might also want to suggest that an upper and lower bound be considered in calculating the bearing capacity where Su is averaged at B, B/2 or possibly B/4 beneath the footing diameter.

FR

A.9.3.2.4

2nd para and Table A.9.3.2

te

The range of friction angle should be reduced to better reflect the actually measured values, i.e. 20-50 degrees

US2

A.9.3.2.4

Page 114

Equation needs to be checked. There is mixing of terms and it is confusing to reader whether this is net or gross bearing capacity. Should be consistent with how bearing capacity is expressed. (i.e. whether adding in volume of soil displaced to equation and whether this should be limited to total vol. of spud can)

US2

A.9.3.2.4

Page 115

Maximum preload should be described as the temporary load that the rig adds to account for expected loading conditions while the rig is on site. Describing maximum preload as equal to the ultimate vertical bearing capacity is a little misleading.

US2

A.9.3.2.7.2

Page 116

The equations are very confusing and require the reader to rewrite the equation after looking up what all the terms mean. In place of all the abbreviations, please writ the equation as to how they should appear or provide all the terms below the equation. Better definition and illustration are required to explain these equations. Equation and text mix Cu and Su. Is added gamma’ V limited to vol. of spud can

FR

A.9.3.2.7.3

3rd para

ed

Delete the sentence about “man-made punch-through risk”, which is already mentioned in clause A.9.3.2.2

US2

A.9.3.2.7.3

Page 117

Examples and equations mix Cu & Su and do not include volume of soil displaced by spud can. It appears that the way this whole section is portrayed is confusing and needs work.

FR

A.9.3.2.7.4

Fig. A.9.3.8

ed

Delete “Dense” at the sand/clay interface

US2

A.9.3.2.7.4

Page 118

Maybe I am missing something here but it would appear that AH gamma’ should be added and that A l gamma’ should be subtracted? Are equations dependent upon the spreading factored selected?

US2

A.9.3.2.7.4??

General Comment

Suggest that the author provides a GOOD example of computations for each method presented so that the practitioner can understand how terms and averaged values are used and how these different equations should be applied.

US2

A.9.3.3 –9.5

Page 120 to134

While the author may know and understand how this section is supposed to be used it leaves the reader wondering what this is all about and where and how to apply all these equations. There are no figures to help in the explanation and terms such as Capacity Envelopes are mentioned with out presenting what these are suppose to resemble or how they can be used. Very disappointing!

FR

A.9.3.3.3

Last para

ed

Delete the last paragraph since deep penetration of spudcans in sand is very unlikely or impossible

US2

A.9.3.3.7.4

Page 118

I believe that most practitioners would prefer to see the actual equation using terms which can be related to versus substituting another term which must be looked up under terms and definitions which may be 50 or more pagers away. (Ex Qu,b in place of 6 Su)

FR

A.9.3.4.3

te

Add “When results of CPT tests are available, the shear modulus G can be determined from by correlation with the measured in-situ cone resistance (Lunne, Robertson and Powell, CPT in geotechnical practice,1997)

CA

A.9.3.4.3

Equation and guidance on IrNC

te

Guidance is given on relating rigidity index to plasticity index. These correlations are just that – empirical correlations without much physical basis. Their applicability beyond the area they were developed (GOM?) is unknown. Also note that Ir is a well defined and measurable parameter (ratio of small strain modulus to undrained shear strength).

Delete guidance on values of Ir. Maybe provide guidance on how to determine su (see A.9.3.2.3) and G (from shear wave velocity)

FR

A.9.3.4.4

te

Add “When results of CPT tests are available, the shear modulus G can be determined by correlation with the measured in-situ cone resistance (Lunne, Robertson and Powell, CPT in geotechnical practice, 1997)

CA

A.9.3.4.4

Equation and guidance

te

The method proposed for shear modulus is based on the “seabed vertical reaction under still water conditions”. A much better method is to measure shear wave velocity and determine G directly from it. Also no guidance is given on how to estimate “seabed vertical reaction under still water condition”, and it is not at all clear what it is.

State: For sands the initial, small strain shear modulus is best determined from measured shear wave velocity and Gmax = (Vs2. If such data are not available, suitable empirical or semi-empirical methods may be used to estimate shear modulus.

FR

A.9.3.6.4.1

ed

Reference “Andersen [36]” to be checked (noted Andersen [18]in clause A.9.3.4.1 and Anderson [55] in the legend of Fig. A.9.2-1)

FR

A.9.3.6.6

1st para

ed

…due to bearing capacity failure during (to) preloading…

FR

A.9.3.6.6

5th para

ed

…

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