Shell Guidelines Heavy Lifting Criteria

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1 •. \ ) .

SHELL

ENGINEERING·

REFERENCE DOCUMENT

MANUAL:

GUIDELINES FOR LIFTING

POINTS AND HEAVY

LIFT

CRITERIA

Document Number : EM/039

Rev: 3

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UEOE/11 is the appointed Custodian of this document and must always be

consulted for advice on validity and currency

by

a user.

Custodian

Name:

Ref. Ind.:

Signature :

Date:

A WvanBEEK

UEOE/11

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Authorised

Name:

Ref. Ind.:·

Signature:

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RMUNCASTER

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-* EM/039 Rev 3 1991 REVISION RECORD REVISION No/DATE

REVISION DETAILS REVISED BY: REF. IND

0/June 1985

1/June 1987 This manual has been extensively revised in F. Mohaqmad accordance with current ERD format procedure (see

Preface).

Section 3 has been revised to clarify design require-ments for heavy lifts.

Section 4.4.8 is corrected to allow a reduced safety factor for certain types of sling. Reference is made to cable laid slings for heavy lifts.

Section 7.1- Equation (2) is corrected ..

2/Aug 1989 Amendment, dated 3151 July 1987, removed. Design B. Irvine Code References updated, Clarification of Lifting

Point Proof Test Requirements.

3/Dec 1991 Manual split into two parts to cover: W.G. Laver Part 1 - Guideiines for design fabrication and

inspection of lifting points (intended for packages up to 1000 tonnes).

Part 2 - Heavy Lift Criteria (Intended for packages exceeding 1000 !annes - traditionally modules and Integrated decks).

UEN/31

UENM/1

UEOE/11

This document should be reviewed within one year of the last revision date. However, the user of this document must always consult the appointed custodian for advice on validity and currency.

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i.

To be completed by Amendment Proposer (Photocopy and leave original in binder)

TO: UEOE/24 FROM:

COPY: EXTN: DATE:

AMENDMENT TO ERD NUMBER REVISION

PROPOSAL:

JUSTIFICATION:

To be completed by ERD Administration

APF NUMBER: TARGET DATE: APPROVE I REJECT

COMMENTS OF: CUSTODIAN SPONSOR

COMMENTS FROM CONTRIBUTORS: (Only if specifically requested by Custodian)

DISTRIBUTE TO:

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EM/039 Rev31991

(lV'a)

Dynamic Amplification Factor {Fh) Lifting Point Design Load

(VY'a)

Four Point Lifts Tandem Crane Lifts

Alternative Lifting Arrangements Lateral Loads

Padears

GENERAL DESIGN CRITERIA FOR LIFTING Sling Angle

Material Selection Design Stresses

Practical Considerations Lifting Point Attachments Lifting Point Location Dimensioning Cheek Plates Weld Design Bolted Connections Lifting Eyes and Lugs Slings and Shackles

FABRICATION, INSPECTION AND TESTING DOCUMENTATION

APPENDICES

Dynamic Amplification Factor Derivation

13 13 13 13 14 14 14 14 14 15 15 15 16 16 16 16 16 16 16 17 18 18 18 19 19 19 19 20 20 20 20 21 22 22 22 22 23 25 25 25

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7.5

7.6

Properties of Lifting Eyes and Lugs Padeye Design Example

PART 2 HEAVY LIFT CRITERIA FINAL REPORT TRANSMITTAL LETTER

DISTRIBUTION LIST

SECOND DRAFT REPORT· 27TH NOVEMBER 1990 1 1.1 1.2 1.3 1.3.1 1.3.2 2 2.1 2.2 2.2.1 2.2.2 2.2.3 2.2.4 3 3.1 3.2 3.3 INTRODUCTION General Project Management Lift History

Single Crane Lifts Dual Crane Lifts SUMMARY Scope of Work Results

Single Hook Lift

Criteria Comparison. Single Hook Lifts Dual Lift

Criteria Comparison. Dual Lifts CONCLUSIONS

Static Analyses Dynamic Analyses References

APPENDIX 1.0 GUIDELINES FOR THE DESIGN OF MODULE LIFTING SYSTEMS

1 2 2.1 2.2

2.3

2.4 2.5 2.6 2.7 2.7.1 2.7.2 2.8 2.8.1 2.8.2

2.8.3

2.9 2.9.1

2.9.2

2.10 2.11 2.11.1 2.11.2 2.11.3 2.11.4 2.11.5 2.11.6 2.11.7 3 INTRODUCTION DESIGN GUIDELINES Module Weights Rigging Weight

Dynamic Amplifications Factors Lift Configuration

Lift Geometry

Module Tilt and Allowable CG Zone Lift Point Loads

Dual Crane Lifts Single Crane Lifts Sling Design Single Slings

Multiple Length Slings Grommets

Dynamic Hook Load Dual Crane Lifts Single Crane Lifts Crane Capacity Lift Point Design Design Loads Allowable Stresses Lift Point Geometry Cast Padears Trunnions Pad eyes Shackles INSTALLATION AIDS · Page 5 of 149 29 30

46

47 48 48 50 50 50 51 51 52 52 52 53 53 54 54 55 60 60 60 61

64

65 65 66 66 67 67 67 67 68 68 69 69 70 70 70 70 70 70 70 71 71 72 72 73 73

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3.1 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 3.2 3.2.1 3.2.2 3.2.3 3.3 3.3.1 3.3.2 3.3.3 4 4.1 4.1.1 4.1.2 4.1.3 4.2 4.2.1 4.2.2 5 6

Module Guidance Systems General

Module Movement Limitations Bumpers and Guides

Pins and Buckets Design Forces

Design Considerations Sling Laydown

General

Sling Configuration

Sling Laydown Platform Design Tugger Line Attachment General

Attachment Position Attachment Design

OPERATIONAL CONSIDERATIONS Slings and Grommets

EM/039 Rev 31991

Manufacture, Inspection and Certification Re-use of Slings and Grommets

Sling Handling Shackles Certification Re-use of Shackles GLOSSARY OF TERMS REFERENCES

ATTACHMENT 1.0 DYNAMIC AMPLIFICATION FACTORS

1 1.1

DYNAMIC AMPLIFICATION FACTORS General

ATTACHMENT 2.0 SKEW LOAD FACTOR- SINGLE HOOK LIFTS ATTACHMENT 3.0 WORKED EXAMPLES

3 3.1 3.2 3.3 Table 1 2 3 4 5 6 7 8 9 10 11

DYNAMIC AMPLIFICATION FACTORS General

Single Hook Lift Example Dual Crane Lift Example

TABLES

Dynamic Amplification Factors (Fh) For Light Packages Minimum Size Fillet Welds

Typical Sling Properties

Dimensions and SWL of 'GREEN-PIN' Shackles Dimensions and SWL of 'McKissick' Shackles Dimensions of Round and Oval Eyes

Dimensions of Triangular Lifting Eyes Dimensions of Lug Fittings

Lift Criteria Comparison -Single Crane Lifts Lift Criteria Comparison -Dual Lifts

References used in this Document

73 73 73

74

75 75 75 76 76 76 76 76 76 76 76 76 76

77

78 78 84 85 85 85 87 88 88 88 88 94 Page 15 22 27 28 28 29 30 30 56 58 62

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Fig ₃₆ 1 Dynamic Amplification Factors

2 Cruciform for CG Location

37

3 Positioning of CG for Pad eye Load Calculation

37

4 Simplified Representation of Package Tilt

38

5 Padear Lifting Arrangements

38 39 6 Typical Padear Details

7 Preferred Padeye Design Details

40 41

8 Stability of Packages 42

9 Typical Shackle Details 10 Lifting Eyes and Lugs

43

11 Plan View of Package in Design Example

44

12 Padeye Design Example

45 101 13 Sling Configurations

' - ₁₄ Lift Point Design Loadings

102 103

15 Cast Padear 104

16 Trunnion 105

17 Pad eye

18 Bumpers and Guides (Type 1)

106

107

108 109

21 Pin and Bucket Guide 110

22 Stabbing Cone

23 Impact Velocities (Module Setting)

111

24 Module Impact Loads, Single Lift

112

25 Module Impact Loads, Dual Lift

113 114

26 Sling Design DAF 115

27 Hook Load OAF

28 Typical Cable Laid Constructions

116

29 Lift Point Loads- Dual Crane Lift (sheet 1 of 2)

117

30 Lift Point Loads- Dual Crane Lift (sheet 2 of 2)

118

31 Single Hook Lift Geometry

119

32 Lift Point Loads- Single Crane Lift

120

33 Skew Load Factor Graphs

121

34 Single Hook List Skew Load Factor (sheet 1 of 24)

122

35 Single Hook Lift Skew Load Factor (sheet 2 of 24)

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

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57

58

59

60 61 EM/039 Rev 31991

Single Hook Lift Skew Load Factor (sheet 24 of 24)

Lift Design Calculation Chari Allowable Centre of Gravity Zones Single Crane Lift Example

Dual Crane Lift Example

145

146

147

148

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In this third rev1s1on of EM/039 there have been changes to content and format. The revJsJon has been prompted by the issue of a guideline document for the design of the lifting systems for heavy offshore modules in air by semi-submersible crane vessels. This document was prepared following a joint industry project (JIP) carried out during 1990 and in which Shell Expro participated.

The Manual has therefore been split into two parts.

The first part contains guidelines on the design fabrication and inspection of lifting points and is in essence of similar style and content to the previous Rev. 2 version, but updated.

The second part contains extracts from the unabridged version of the 'Heavy Lift Criteria Final Report' prepared by Brown and Root (BRV) under the auspices of the JIP. The main deliverable from this JIP WAS THE GUIDELINES FOR THE DESIGN OF MODULE LIFTING SYSTEMS which is reproduced in full.

The reader should be aware that whilst the GUIDELINES were prepared with joint industry input there is no obligation from any of the major offshore installation contractors, warranty surveyors or others to follow the criteria rigidly. The object of the JIP was to standardise the lifting criteria but this proved to be too ambitious a task and so lifting contractors, warranty surveyors and others will continue to use their own criteria developed over a number of years experience. However, the differences between the GUIDELINES developed during the JIP and other criteria are very small and similar results can be expected. For front end Engineering or Conceptual Design then the JIP GUIDELINES may be used, but once an installation Contractor has been appointed then the appropriate criteria should be discussed and agreed.

PART 1 of this Manual describes the criteria to be applied to the design, fabrication and inspection of lifting points for light and medium packages up to 1000 tonnes lift weight. These criteria are mainly intended for lifting points on packages for offshore lifting. However, appropriate modifications to the criteria for onshore lifting are also specified and similar principles apply to offshore and onshore lifts.

PART 2 of this Manual contains the main guidelines for the design of the lifting systems for heavy offshore modules in air by a semi-submersible crane vessel and relevant extracts from the main JIP report. The document was prepared following a joint industry project study carried out during 1990. The guidelines do not specifically cover lifts incorporating floating spreader beams/frames or offshore lifts of jacket structures although they can be applied under certain circumstances.

Due to the two part nature of the manual there may be some duplication of information but this is unavoidable and information in Part 2 for heavy lifts may be appropriate for light and medium lifts and vice versa.

Proposed modifications to this Standard shall be addressed to, and agreed with the appointed custodian, UEOE/11.

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EM/039 Rev 3 1991

PART 1 GUIDELINES FOR DESIGN FABRICATION AND INSPECTION OF LIFTING

POINTS

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SIPM Shelllnternationale Petroleum Maatschappij B.V. Shell Shell U.K. Ltd.

Shell Expro Shell U.K. Exploration and Production.

Purchaser The organisation responsible who carry out the purchasing function, e.g. Shell Expro or a Shell Expro appointed Contractor, Consultant or Agent.

Vendor The supplier of materials or equipment- not necessarily the Manufacturer. Manufacturer The company responsible for the manufacture- not necessarily the Vendor. Contractor The Shell Expro appointed main Contractor for a defined piece of work.

Sub-contractor A company awarded a contract by a Contractor to do part of the work awarded to the Contractor by Shell Expro. The work of the Sub-contractor is carried out under the direction and control of the Contractor. Under its model contracts Shell Expro has the right to review all proposed Sub-contractors, and sub-contracts.

Nominated (to be used with extreme caution) Sub-contractor

Consultant

Agent

A term having a special legal meaning applicable to the unusual case where the terms and conditions of the contract between Shell Expro and the Contractor provide that special terms and conditions apply to any Sub-contractor that is nominated by Shell Expro. Shell Expro model contracts avoid use of the term 'nominated'.

A company awarded a contract by Shell Expro for the company to advise or give guidance on specific subjects. The Scope of Work may include instructions to act as an Agent for Shell Expro (see Agent).

The legal status of any person or company authorised by Shell Expro to act on Shell Expro's behalf on the matters specified in the agency agreement or contract. Third parties can usually rely on the Agent as acting on behalf of and with the authority of Shell Expro, provided that the Agent acts within the scope of his apparent authority from Shell Expro.

Safe Working The maximum mass that an item of lifting gear may raise, lower or suspend under conditions no more severe than the design conditions. The SWL is sometimes referred to as the working limit load (WLL) in British Standards documents.

Minimum Breaking Load (MBL) The load below which a sling will not fracture when tested to destruction in the prescribed manner.

Base Weight The best estimate of the weight of a package exclusive of allowances as defined in EN/001 Weight Engineering Principles and Procedures

Factored Weight Base weight plus allowances. Refer to EN/001 Weight Engineering Principles and Procedures

Light Package A package whose factored weight does not exceed 50 tonnes.

Medium Package A package whose factored weight is between 50 tonnes and 1000 tonnes. Heavy Package

Package Lifting Point

Lifting System

A package whose factored weight exceeds 1000 tonnes. An item requiring to be lifted, onshore or offshore.

A lifting polnC usually

a

pacfeye or a padear, is a structural element and the part of the package or lifting frame connected to the sling.

A lifting system is the combination of package, lifting points, slings and shackles.

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w K

Tz

VJ, VIJ

Wo.

\/1Jd \~Jd~

WJ...

Wr

c. g.

MBL

PWHT

SF

EM/039 Rev31991

SYMBOLS AND ABBREVIATIONS

Padeye hole diameter. Shackle pin diameter. Acceleration due to gravity.

Padeye plate thickness (including cheek plates). Shackle jaw width.

Dynamic amplification factor. Significant wave height. Crane system stiffness.

Most probable zero upcrossing period. Hook speed.

Package base weight. Weight allowance.

Lifting point design load. (Includes D.A.F .). Sling and Shackle design load.(Excludes D.A.F.). Hook load due to package.

Weight of rigging.

Angle formed between horizontal and e.g. of package. Effective Jack of fit in the slings.

Direct stress (axial, bearing or bending). Equivalent stress.

Yield stress. Shear stress

Sling angle to horizontal. Centre of gravity Minimum breaking load. Post weld heat treatment. Sling safety factor offshore.

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The recommendations contained in this Manual (Part 1) present design, fabrication and inspection criteria for lifting points up to 1000 tonnes lift weight. The recommendations apply to offshore lifting although appropriate relaxations for onshore lifts only are also specified.

It is intended that the manual be used as a basis for the design of lifting points and it should also be issued to Shell Expro Representatives onshore and offshore, as a basis for their assessment of the acceptability for safe lifting of packages.

Rules and codes for offshore lifting have been produced by DnV and Lloyd's Register of Shipping. Refer to DnV Rules for the Design, Construction and Inspection of Offshore Structures, Appendix H, Marine Operations Section Hi: Lifting and Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment.

This Manual deals with the topics covered by DnV (load definition, design to allowable stress criteria, sling and shackle selection etc.) but in more detail. The LRS Code is a general document covering all types of lifting appliance. Only those recommendations concerning lifting with cranes have been considered in drawing up this Manual. A single load factor to be applied when designing for lifting is required by API Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms.

For medium and heavy lifts, the API approach is conservative, but, for light lifts the load factor of 2.0 recommended by API is consistent with this document.

In general, the criteria outlined hereafter are applicable to any weight of package. However, the load factors vary considerably between those that are appropriate for the lift of a light package, and those that are appropriate for a heavy package to reflect, for example, differences in .the hook speed of the crane and dimensional tolerances on lifting point positioning.

To avoid unnecessary conservatism, specific recommendations for lifting point design for light packages are presented in Section 2 Specific Design Criteria for Lifting of Light Packages (Wh Sot).

For medium packages up to 1000 tonnes in Section 3 SOt but 1 OOOT. For heavy packages, greater than 1000 tonnes then guidance is recommended from Part 2- Heavy Lift Criteria Final Report. The following are applicable to all packages except where specifically stated otherwise. Refer to Section 4 General Design Criteria for Lifting, Section 5 Fabrication, Inspection and Testing and Section 6 Documentation.

In general, the allowable stresses used in this document are also applicable to castings. Refer to Section 4.3 Design Stresses. However, for lift points employing castings it is recommended that for detailed design finite element analysis is used. Material and fabrication requirements for castings are the subject of a separate specification. Refer to ES/148 - Structural Cast Steel Materials for Offshore Installations.

The Appendices (Section 7) contain general information which may be useful to the engineer when evaluating lift point design.

1.2 References

1.2.1 British Standards 8S1290

8S4360

8S6166, Pt. 1 and 2

Specification for wire rope slings and sling legs for general lifting purposes

Specification for weldable structural steels Lifting slings, rating and marking

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BS62i0

EM/039 Rev 31991

Code of practice for the safe use of wire rope slings for general lifting purposes

1.2.2 Other National/International Standards

America Institute Construction (AISC)

of Steel Specification for Design, Fabrication and Erection of Structural American Petroleum

(API)

Steel for Buildings

Institute Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms

American Welding Society (AWS) Structural Welding Code- Steel Guidance Note PM20 from the Cable laid slings and grommets Health and Safety Executive

Del Norske Veritas Rules for the Design, Construction and Inspection of Offshore Structures, Appendix H, Marine Operations Section H1 :Lifting Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment

1.2.3 Shell Expro Documents

Engineering Reference Documents (EROs) Standard ES/096

Info. Note EN/001 Standard ES/148 Standard ES/006 Standard ES/088

UEOS-3142-001

1.2.4 Others

J.W Bunce and T.A. Wyatt Brown and Root

Specification for Structural Steel Materials for Offshore Installations

Weight Engineering Principles and Procedures

Structural Cast Steel Materials for Offshore Installations Topside Facilities Structural Design, Offshore Installations Steel Substructures and Ancillary Attachments Structural Design Offshore Installations

Lifting Gear and Lifting Appliances

Development of Unified Design Criteria for Heavy Lift Operations Offshore: OTC4192, 1982

Heavy Lift Criteria Report

2 SPECIFIC DESIGN CRITERIA FOR LIFTING OF LIGHT PACKAGES {Wh< 5DT)

This Section describes the steps required to design lifting points for the safe lifting of packages which

give rise to hook loads less than 50 tonnes.

The following steps are required to establish the hook weight (W1):

(1) Establish base weight (W) and position of centre of gravity (e.g.) of the package

(2) Establish weight allowances (Wa) to be used for the lifting point design. The weight allowance to be used will vary depending on the accuracy of the base weight. If it is a preliminary engineering estimate then Wa.

=

0.2W, whereas if it is a weighed itemWa.

=

0.02W. Guidance on the correct weight allowance to use is available in EN/001 Weight Engineering Principles and Procedure.

'Na.

varies depending on quality of information, 0.2W < Wa. < 0.02\1\1. The sum (W + Wa) is the factored weight of the package in the lift condition.

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l

-particular environmental conditions, appropriate to the expected method and nature of the lift. D.A.F. values are quoted in the Table below, with a recommendation to use 2.0. These values are calculated assuming the supply boat heave is the same as the wave height.

Table 1 Dynamic Amplification Factors (Fh) For Light Packages

Onshore lift 1 _{Offshore Lift}2 _Upper _{Offshore LIFT}3 _{Offshore Lift: Lower}

Bound Recommended Bound

..

1.25 2.5 2.0 1.3

I.

NOTES:

1.

This factor may also be applied to a lift from place to place on a platform by the platform crane.

2. Based on a seastate represented by Hs = 4-0 m, Tz = 7.5 sec (Beaufort 7).

3. Based on a seastate represented by Hs = 2.~m. Tz = 6.0 sec (Beaufort 5).

4. Based on a seastate represented by H = 0.6 m, Tz =

p.O

sec (Beaufort 2).

The formulae used to obtain the values of F1, as listed in the table above (F1) For Light Packages', above, are given in Appendix 1 Dynamic Amplification Factor Verification. These formulae can be used to calculate F 1 values depending on purposes. An F 1

=

2.0 is recommended for the design of attachment points which covers the majority of lift situations.

(4) The hook load (W1) can be calculated as:

=

W1

=

F 1 (W + Wa). 2.2 Lifting Point Design Load (Wd)

2.2.1 Four Point Lifts

For 4 point lifts without spreader beams or bars, the hook weight (W1) is distributed so that any diagonal pair of lifting points is assumed to carry 0.75 W1 vertical load. The 0.75 Wh is then

distributed between each lifting point of the pair according to its distance from the e.g. This distribution allows for the extensibility of the slings, flexibility of the lifted object etc. The lifting point load is calculated using the sling angle (¢) to the horizontal. The procedure is repeated for the other pair of lifting points. The lifting point design load (Wfl.) is defined as the load on the most heavily loaded lifting points. Wd is applied to all the lifting points. Wd,. (without the D.A.F.) is used for the sling and shackle

design. ·

If loose spreader bars are used the hook weight is more evenly distributed over the lifting points so

that any diagonal pair is assumed to carry 0.60 W1 vertical load.

2.2.2 Alternative Lifting Arrangements

For 1, 2 and 3 point lifts the distribution of hook weight can be calculated because it is statically determinate. The calculation should consider the most onerous combination of:

(1) the position of e.g. of the package.

(2) BS 6166 requirement that the load does not tilt more than 6° when lifted. Although this maximum angle of tilt is greater than that allowed for heavy lifts (1.1 °) it may still require the use of slings of unequal length resulting in some lifting points being much more heavily loaded than others. Furthermore the permitted maximum angle of tilt may have to be reduced if it causes

installation difficulties. Refer to BS 6166 Lifting Slings Rating and Marking.

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EM/039 Rev31991

(3) Padeyes and other internal members (and both end connections) framing into the joint where the padeyes is attached and transmitting lifting forces within the structure should be designed for a minimum load factor of 2.0 applied to the calculated static loads. Refer to API Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms.

2.2.3 Lateral Load

The lifting points should be orientated so that as far as possible the theoretical centre of gravity lies in the plane of each. A nominal lateral load of 5% of the lifting point design load

("'Va)

acting at the point of sling load application, normally top of the padeye, should be applied simultaneously with all the other design forces. This lateral load accommodates some inaccuracies in fabrication and e.g. position, and is equivalent to a 3° misalignment of the plane of each lifting point from the design hook position.

3 SPECIFIC DESIGN CRITERIA FOR LIFTING OF MEDIUM PACKAGES(> SOT BUT< 1000T)

This Section describes the specific requirements for the design of lifting points for medium packages (>50 tonnes but< 1000 tonnes). Each lift should be Engineered on an individual basis. Onshore lift requirements are similar to offshore with the exception of Dynamic Amplification factors.

3.1 Hook Load ('N.l)

The procedure for calculating Wh is similar to that for light packages described in

Se~tion

2.1 Hook Load (Wh), but Wo. and F 1 will be different as indicated below.

3.1.1 Weight Allowances

(IIlJa.)

This Manual treats weight allowances in a very simple way for light packages. Refer to Section 2.1 Hook Load (Wh). For medium and heavy packages a weight growth philosophy should be used for estimating the value of

Wa.,

as described in EN/001 Weight Engineering Principles and Procedures.

3.1.2 Dynamic Amplification Factor (F h)

Medium and heavy lifts are made by the main or auxiliary hoists of large crane vessels. The hook speed which a main or auxiliary hoist can achieve is much lower than that of the whip hoists. The packages are off loaded from the deck of the crane vessel or of a large cargo barge. In both cases the

vessel motions are much less than those of a supply boat in the same sea conditions, and F his generally lower for heavier packages.

Typical values ofFh are given in Figure 1 Dynamic Amplification Factors.

3.2 Lifting Point Design Load (lr'ITa)

3.2.1 Four Point Lifts

For 4-point lifts without spreader beams or bars, the hook weight (Wh) is distributed so that any diagonal pair of lifting points is assumed to carry 0. 75 Wh vertical load.

The 0.75

W1

is then distributed between each lifting point of the pair according to its distance from the e.g. The 75/25 split is introduced to take into account sling length inaccuracies. Maximum package twisting takes place when slings across one diagonal are short and slings on the other diagonal are long. The magnitude of the twist is also dependent upon the package stiffness, a flexible package allowing a more even split in load between diagonals.

The lifting point load is calculated using the sling angle (cD) to the horizontal. The procedure is repeated for the other pair of lifting points. The lifting point design load (lNa) is defined as the load on the most heavily loaded lifting point. Wa is applied to all the lifting points.

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sling length tolerances as specified by the manufacturer;

true sling stiffness;

the theoretical package stiffness;

• the theoretical load distribution within the package.

Once an analysis for a package has been carried out considering these four factors, the initial lifting point design should be checked using the load generated.

Further comments on this aspect appear in Appendix 2 Lifting Point Design Load Derivation.

If loose spreader bars are used the hook weight is more evenly distributed over the lifting points so that any diagonal pair is assumed to carry 0.60 vertical load.

3.2.1.1 Position of e.g. of Package

Having established the theoretical centre of gravity of the package it must be checked that it falls within the cruciform shown in Figure 2 Cruciform for cg Location and Positioning of cg for Padeye Load Calculation.

The cruciform limits above are for packages using matched slings. Packages that use unmatched slings will need to be considered separately; for these cases the cruciform may need to be redefined and such redefinition agreed with the installation contractor.

During early stages of design, the centre of gravity (e.g.) is assumed to be at an extremity of the cruciform, for the purpose of establishing Wd. Refer to Appendix 7, Cruciform For Cg Location And Positioning Of cg For Padeye Load Calculation.

For packages whose centre of gravity is more precisely defined, a less conservative assumption for e.g. position may be used. For example, for living quarters modules a 1m shift of the theoretical centre of gravity in the most onerous direction is acceptable.

3.2.1.2 Permissible Tilt of Package

The cruciform limit (x) is defined by an acceptable package tilt for ease of installation of the package.

The maximum acceptable module tilt is generally 2%, slope-equivalent to 1.14°. Refer to Figure 4 Simplified Representation of Package Tilt and Padear Lifting Arrangements

The above assumes that two pairs of matched slings are used, so that the hook is above the longitudinal or lateral centre line of the module. Refer to Figure 2 Cruciform for cg Location and Positioning of cg for Padeye Load Calculation.

3.2.2 Tandem Crane Lifts

3.2.2.1 Centre of Gravity

Locations for centre of gravity of all tandem lifted packages should be quoted with an allowance for calculation inaccuracies and probable deviations during the course of design and fabrication. Refer to Section 3.2.2.4 Package Tilt. This allowance will be reduced as design progresses. No further allowances shall be applied for possible variations in centre of gravity location when designing slings and lifting point.

Page 17 of 149

·1

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3.2.2.2 Sling Load Distribution

EM/039 Rev31991

Tandem crane lifts are generally stati"cally determinate and variations in sling lengths within normal tolerances specified by manufactu1·ers give insignificant deviations in sling load. However, some racking loads may be imparted to the package while it is being lifted off the barge; to allow for this it shall be assumed that loads in slings attached to any one hook (2 slings per hook) are distributed in the ratio 55/45.

3.2.2.3 Sling Angles

For slings attached to the crane hook, the effect on the determination of loads and clearances of variations in angles to the horizontal plane of ±5° from the nominal values calculated from the lift geometry, and any limitations imposed, shall be determined.

3.2.2.4 Package Tilt

Redistribution of load between the cranes due to the package tilting in the longitudinal direction because of variation in hook heights shall be estimated from changes in the relative distance of the centre of gravity between cranes, assuming a maximum tilt of 0.02 radians.

Transverse tilt of the packages shall also be limited to 0.02 radians. The location of the centre of gravity of the package should be restricted to comply with this requirements.

3.2.3 Alternative Lifting Arrangements

Alternative arrangements such as 3-point lifts are often statically determinate and may allow reduced design loadings due to different load distribution mechanisms. General design guidance is not possible and lifting point loads must be derived on a case by case basis.

Particular attention must be paid to the possible variations in package e.g. and changes in design loads due to package tilt.

3.2.4 Lateral Loads

For medium and heavy packages the lateral load should be 5% of Wd, applied at the top of the pad eye or across the top of the padear stubs. This load should be considered to act concurrently with the in-line loading.

For spreader beams 8% of the vertical lift point force shall be used to account for possible adverse horizontal load distribution or dynamic behaviour.

3.3 Padears

The padear is a development due to the advent of very heavy packages for offshore lifting. The maximum practical hook weight for a shackle lifted package is of the order of 2000 tonnes, giving a base weight of approximately 1500 tonnes.

Practicalities dictate that above this approximate limit a doubled sling and padear arrangement should be used. The slings employed have spliced eyes at each end. Refer to Figure 4 Simplified Representation of Package Tilt and Figure 5 Pad ear Lifting Arrangements.

The forces in each leg of the sling will be different due to frictional losses over the hook or stubs. These frictional losses are taken into account by a 45/55 distribution in the sling loads S 1 and S 2 in

addition to the other load distribution factors. Therefore a padear has to be designed for substantial

out of plane bending. ·

The use of castings is a viable alternative to fabricated steel padears and can lead to significant cost savings. Castings can now be produced of adequate strength, toughness and weldability. They are also more tolerant than fabricated padears, of changes in the package centre of gravity.

(19)

permitted; the extent of the yielding zone shall be approved by Shell Expro. It is recommended that, in cases where the casting manufacturer does not have sufficient capability to perform the analysis as indicated above, the finite element analysis shall be carried out by a competent subcontractor.

4 GENERAL DESIGN CRITERIA FOR LIFTING

4.1 Sling Angle

No sling angle should be less than 45° to the horizontal. The recommended sling angles are 55° -65° to the horizontal, to achieve a reasonable balance between load minimisation and sling length. As a general guide, initial lifting point design should be based on a sling angle of 55°.

The lengths of slings should normally be within tolerance of± 0.25% of their nominal length.

4.2 Material Selection

The material used for lifting points, their attachment to the package and lifting beams (if required) should comply with the requirements set out in ES/096 Specification for Structural Steel Materials for Offshore Installations.

It should be noted that materials having guaranteed through-thickness properties are recommended for lifting points, and the plates or members to which they are attached, unless the design is such that through-thickness stresses are avoided.

4.3 Design Stresses

Allowable stresses for lift design shall be in accordance with the requirements of the AISC specifications, with no increases in allowable stresses. Refer to ES/096 Specification for Structural Steel Materials for Offshore Installations. These allowable stresses are listed below for guidance but the designer should use information from the latest edition of the referenced publication.

Nature of Applied Stress Tension Compression Bending Shear Bearing 1 Equivalent Buckling

Where "Y is the yield stress of the material.

Allowable Stress 0.6" 0.6 (maximum) "Y

0.66 t;Jy [<'ICI,I tn' 0 '7S'

:h

I}JC.c· l<'l

0.4 t;Jy 0.9 °Y 0.75"Y

AISC Tables

NOTES: 1. The bearing stress value is based on the contact area:

= Shackle pin diameter

= Padeye plate thickness including cheek plates (if used)

2. The equivalent stress ("0

) at a given point is:

-

'

2 . 2

1

2 y, t;J

-@xx.

+

t;Jy~

-

Oxx

+ Oyy + ;;JT.) .:': 0.75 Y

(20)

Where:

EM/039 Rev31991

Oxx

=direct stress in x direction (due to axial and bending loads)

0

YY =direct stress in y direction

-r = algebraic sum of shear stress acting at the given point

4.4 Practical Considerations

4.4.1 Lifting Point Attachments

It is strongly recommended that the lifting points are designed to transfer load in shear rather than tension. Through-thickness loads should be avoided. For example, padeye plates should be slotted through horizontal flanges and welded directly to vertical web plates. For examples of the preferred design details for padeye attachment to hollow and I -section members, refer to Figure 7 Preferred Padeye Design Details.

However, other details are acceptable if sufficient analysis is provided to demonstrate that stresses are within allowable limits.

4.4.2 Lifting Point Location

Lifting points should be attached to locations on the package which are capable of withstanding the lifting point design load, and these locations must be checked for strength using the allowable stresses quoted in Section 4.3 Design Stresses.

Lifting points should be located such that there is easy access for slings and shackles. Structural detailing that avoids having to cut-off the lifting points after installation is recommen.ded. Wherever possible, the centre of gravity of the package should be below the lifting points.

Where the centre of gravity of the package is above the lifting points, stability will be enhanced by:

• use of a lifting beam/frame;

use of long slings such that the angle ¢ formed between the horizontal and the hook is substantially greater than the angle ~ formed between the horizontal and the centre of gravity. Refer to Figure 8 Stability of Packages.

4.4.3 Dimensioning

4.4.3.1 Padeyes

Padeyes should conform to the following criteria with respect to shackle pin size for ease of fitting and the avoidance of small contact area. The following equations apply. Refer to Figure 9 Typical Shackle Details.

dp _:::25mm

d1 =Diameter of padeye hole

(21)

tmax ~ O.Bw !min:::: 0.6w

Note that dimension H can be important for fit-up of the shackle on the padeye. Refer to Figure g Typical Shackle Details.

This dimension varies with different shackle designs, and the shackle manufacturer must be consulted for its value for a given shackle.

Clearance should also be provided around the padeye to ensure the shackle pin can be inserted and removed.

A minimum clearance tm of 0.5 times the sling diameter should be allowed between the inside length of the shackle and the combined length of sling diameter plus padeye main plate radius.

4.4.3.2 Padears

The dimensioning of the padears is mainly govern.ed by the following:

e the central stiffener plate (shear plate), refer to Figure 6 Typical Padear Details, should be

slotted through the main plate and should be designed to transfer the total sling load into the main plate.

the padear stubs should only be regarded as a bent circumference for the sling eye. The diameter of the pipe should be at least three times the sling diameter, or four times if the main body of the sling is bent;

• the main plate thickness (or, if more than one main plate will be used, the sum of the main plates' thickness) should be equal to or larger than the padear stiffener plate;

as the sling will stretch out at the contact area during lifting (bearing length

=

1.3 sling diameter) the width of the stub should be minimum 1.5 times the sling diameter;

the cover plate/keep plate should protrude about 75% of the sling diameter at the bearing area and at least 1 OOmm above the centre of the pipe. To install the sling an overall clearance of 1.5 times the sling diameter is required.

4.4.4 Cheek Plates

The requirements for bearing and shear pull-out stresses and for shackle clearances may mean that cheek plates are required even for light lifts. Refer to Section 4.3 Design Stresses and Section 4.4.3

Dimensioning.

The radius of cheek plates should be no more than the radius of the main plate minus the cheek plate thickness.

If the pad eye main-plate is not circular at its free end, then the minimum distance from the edge of the cheek plate to the outside edge of the main plate shall be the cheek plate thickness.

The maximum cheek plate thickness for the calculation of allowable stresses shall be taken as the lesser of:

'X

main plate thickness,

(22)

EM/039 Rev 3 1991

3 x the weld length of the cheek plate to the main plate

However, thicker cheek plates may be designed to satisfy clearance requirements.

Wheri cheek plates are used, the hole for the shackle-pin should be drilled after welding the cheek plates to the main plate.

4.4.5 Weld Design

In general, full penetration welds are required for the connections between the padeye and the

f,

structure. Fillet welds are adequate for welds to cheek plates. However, for light lifts fillet welds may h! be used for every connection provided that adequate strength is demonstrated and that the welds are

1

loaded in shear, not tension.

In the design of cheek plate welds it is recommended that a safety factor of 2 be applied to the load which the weld is to carry. This factor is applied to allow for load distribution along the weld.

The welds, full penetration or fillet, should be designed according to the AISC and AWS codes applicable to the design of the package structure. Refer to AISC Specification for Design, Fabrication and Erection of Structural Steel for Buildings and AWS Structural Welding Code- Steel.

Table 2 Minimum Size Fillet Welds

Material Thickness of Thicker Part Joined Minimum 1 _{Size Fillet Weld}

(mm) (mm)

Up to 12.0 inclusive 5.0

Over 12.0 to

4>w0

2 [/'

0

6.0

Over 20.0 to 40.0 8.0

Over 40.0.to'60.0 1tl.O

Over 60.0 12.0

1

Leg dimension of fillet welds

The weld details should be designed for easy access for welding and inspection. 4.4.6 Bolted Connections

Proposals for bolted connections shall be treated on a case by case basis and be subject to the approval of Shell Expro.

4.4.7 Lifting Eyes and Lugs

The Lloyd's Register of Shipping code for lifting appliances gives details of appropriate dimensions of lifting eyes (round, oval and triangular) and lifting Jugs. These are repeated in Appendix 5 Properties of Lifting Eyes and Lugs. Safety factors against MBL should be 5.0.

4.4.8 Slings and Shackles

The safe working load (SWL) of the sling is the maximum load which the sling is allowed to carry. The

SWL should be greater th,an or equal tq the lift point design lo.ad Wd obtained from Section 2.2 Lifting

5:/NL

Y

INc!£

Point Design Load (WD) or Section 3.2 Lifting Point Design Load (WD). ·

The minimum breaking load (MBL) required is the SWL multiplied by the safety factor. Refer to Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment.

(23)

sF= 104/8.85

s·vn

+ 1910 SF= 3.0

10 <

svn.::

160 160 >

svn

In case F J. > 1.6, the MBL is determined as: MBL> ·vva/1.6xSF

Refer to Section 2.1 Hook Load (WH) and Section 3.1.2 Dynamic Amplification Factor.

The above equation only applies to slings constructed in accordance with Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment.

\1 The safety factors above apply provided that the main body of the sling is not used over bearing points

t

less than four times the nominal diameter of the rope, and that soft eyes are not used over bearing

~

points less than the nominal diameter of the rope.

Slings with SWL > 160 tonnes may be of cable laid construction. These are not covered by L\oyds Register of Shipping, and safety factors for these slings should be obtained from HSE PM20Cable laid slings and grommets.

It is important that the slings are not too large for the lift (SWL 2::

Wa~)

because large and over stiff slings may invalidate the75/25% load distribution al)d may be difficult to handle and fit to the shackles. Refer to Section 1.2.2 (4) Lifting Point Design Load (WD).

This can happen if a high Dynamic Amplification Factor

F

1 is used resulting in very conservative slings

and shackle sizes. Given slings and shackles have a high safety factor, minimum 3.0, and include an · element of dynamic loading, a Dynamic Amplification Factor F 1 of 1.0 is recommended for lifting light packages unless more onerous seastates are required for specific lifts, then F 1 = 1.3 would be recommended.

Shackles are usually classified according to their SWL. Only shackles with minimum breaking strength at least four times SWL should be used. For shackles:

For fit-up purposes it is important that shackles are matched to the load.

The properties of typical slings and oftypical shackles is listed, respectively, in Appendix 3 Typical Sling Properties and Appendix 4 Typical Shackle Properties.

Current manufacturers' catalogues must be consulted for design purposes.

5 FABRICATION, INSPECTION AND TESTING

In general, the Codes of Practice and structural specification applying to the fabrication of the package apply equally to the lifting points and their attachments. The following points should be noted.

(24)

(1) (2) (3) (4) (5) (6) (7) EM/039 Rev 31991

Lifting points, spreader beams, etc. shall in general comply with the requirements for the structural steel of the package for fab1·ication and inspection. Materials used in lifting points and welds in connection with lifting points should be 100% non-destructively tested. Fillet welds require only ·wet' MPI. Full penetration welds require ·wet' MPI plus ultrasonic inspection wherever practical. The areas for lifting point welds shall be mapped out onto the surface of the supporting structure and this area, plus 50mm either side of the weld, shall be ultrasonically inspected. If any laminar discontinuities are found the lifting point shall be relocated to avoid such areas, or redesigned to compensate for poor through-thickness properties.

Relative lifting point positions and fabrication tolerances of plate shacl<les, spreader beams, etc. are to be measured. Tolerances must be such that the lateral loading will not exceed the specified levels. Refer tci Section 2.2.3 Lateral Load and Section 3.2.4 Lateral Loads. It is recommended that the tolerances on lifting point orientation are not greater than +2°

Items which are flame cut from plate either manually or automatically are to be ground to give a smooth, notch free, bright metal finish to the faces.

Holes should be drilled after welding, not cut and profiled, to avoid point contacts. Tolerances on pin-hole diameter

fl·)

shall be +2, - Omm.

Each lifting point in regular use (e.g. containers) is to be marked with its Safe Working Load (SWL). This SWL should be the lifting point design load (V•Ta). The marking should be made with white paint in letters not less than 50mm high.

....-c.--Lifting beams, and spreader frames are to be proof-tested in accordance with Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment .

SWL s; 10 Tonnes

/-~

Lr{M

(CXJ-<)

f2il<c(udr-~

1>PJ-f-Proof Load= 2 ~~

10 < SWL < 160 Tonnes

Proof Load= (1.04 x SWL) + 9.6 Tonnes SWL > 160 Tonnes

Proof Load = 1.1

x SWL

For a lifting beam, SWL = W1.

It may be impractical to proof load large lifting beams, i.e. SWL > 100 tonnes. If proof loading is not possible, the design and fabrication of the lifting beams should be certified to the same standards as the package. All lifting beams shall be marked with the SWL. Lifting points for the general construction phase of topside modules and those Which are an integral part of a structure do not, in general, require to be proof tested. Such cases, where a great deal of attention has been given to the loads and stresses, can be accepted by design and inspection only. However when there is an uncertainty proof testing could be carried out at the request of Shell Expro.

(25)

Appliances in a Marine Environment. This inspection should check for wear, damage, COITosion, structural changes etc. In particular, padeye welds should undergo MPI at regular intervals to ensure that cracks or other defects do not propagate as a result of repeated lifts. Parts which are found to be work damaged, .or corroded to a significant degree should be replaced. For guidance purposes generally acceptable levels of wear down are given by LRS but earlier replacement may be required where considered warranted by Shell Expro.

(9) All welding carried out in the fabrication of lifting points and attachment to the package shall be in accordance with the fabrication specification of the package.

(1 0) Inspection of lifting equipment within Onshore Plants is undertaken in accordance with the Factories Act 1961 Section 26.

6 DOCUMENTATION

(1) Generally, the requirements of LRS are to be complied with. Refer to Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment.

Certification requirements for all categories of lifting appliance are outlined. Certificates are to be prepared, and kept available, showing that:

e satisfactory tests have been carried out on the individual items of loose gear and on each

lifting appliance as rigged for its intended mode of operation;

the required Periodical Surveys of each lifting appliance have been carried out.

(2) Written calculations, design drawings, material certificates and weld procedures for all packages are to be supplied to the Shell Expro Project Engineer for approval. The calculations are required before approval of drawings for construction. The material certificates and weld procedures are required before the start of fabrication. All the above should be in accordance with the fabrication specification of the package.

7 APPENDICES

7.1 Dynamic Amplification Factor Derivation

The Dynamic Amplification Factors (F 1) for offshore lifts are based on the assumption that the package is lifted from a supply boat working in the design condition. The extreme design condition is a sea state represented by Hs = 4.0m, Tz = 7.5s, which is the specified limiting sea state for supply boat operations next to a platform. F 1 may be changed if it can be demonstrated that, for instance, the lift will not be attempted in a sea state as severe as the design condition or if the crane parameters do not allow the required hook-speed to be achieved. In the latter case the results of a possible 'hammering' of the package on the vessel deck should be analysed. Generally, only a whip-line or a pedestal crane can achieve a high hook speed.

Simple single degree of freedom models are used to derive Dynamic Amplification Factors th) for offshore lifting of packages. These models give conservative values ofF 1 for most lifting conditions. The following formulae were considered in order to produce recommended values of Fh:

F1

= 1.0 +

4.5

H.tg T~

F1

=

[1.o

+

V11g

(See Glossary for symbols)

.Y

Kg/W

+

V•Ta

+

Wr

.Y

Kg/W

+

Wa

+

Wr]

Page 25 of 149

(-1)

(26)

EM/039 Rev 31991

Equation (1) is derived from that quoted by Lloyd's Register of Shipping Code for Lifting Appliances in a Marine Environment.

Equation (2) is derived from OTC4192, 1982 Development of Unsigned Criteria for Heavy Lift

Operations Offshore.

Equation (2) is preferable because it treats crane hook speed

(Vl.)

and vessel motions as separate terms. This enables values of FJ, to be calculated for low hook speeds.

Onshore Lifting of Light Packages

The following analysis was required for calculation of the values of F h in Table 1 Dynamic Amplification Factors (Fl.) For Light Packages.

Typical value (1 0) and one which does not vary greatly provided slings sizes are matched to the loads they lift. The value therefore applies to both onshore and offshore lifting.

H~

=

0

A value of hook speed one would expect not to be exceeded. This leads to F h = 1.25.

Offshore Lifting of Light Packages

. v1

= 1.6ms-1

H.,=4m

Tz = 7.5s

}

This leads to F h = 2.39 (Eq. 1)

Fh =2.21(Eq.2)

As an upper bound Fh

=

2.5

H.,

=0.6m }

}

This leads to F h = 1.31 (Eq. 1) As a lower bound F h = 1.3

}

This leads to F h = 2.08 (Eq. 1)

Maximum likely hoist speed

Extreme Design environmental conditions

Monitored Design environmental conditions

Operational Design environmental conditions

(27)

especially if the lifted package is not very stiff. Refer to DnV Rules for the Design, Construction and Inspection of Offshore Structures, Appendix H, Marine Operations Section 1-11: Lifting, OTC4192, 1982 Development of Unified Design Criteria for Heavy Lift Operations Offshore and Brown and Root Heavy

Lift Criteria Report. ·

The real force distribution depends on the flexibility of the rigging system and the lifted object, on the lack-of-fit of slings due to fabrication errors, crane hook arrangements, tolerances on the e.g. position etc.

A better method of calculating force-distribution than assuming a 75/25 split is described in OTC4192, 1982 Development of Unified Design Criteria for Heavy Lift Operations Offshore.

This treats the effective lack-of-fit in the slings as an explicit design parameter and describes it by £ ,

which is the sum of the effect of fabrication tolerances plus the sling manufacturers' guaranteed tolerances. The load distribution can then be assessed assuming an error of+ on both slings on one diagonal and - E on both slings on the other. The effect of package distortion is included in the analysis.

This method may be used if a relaxation of the 75/25 split is required or if the 75/25 distribution has to be justified because, say, sling tolerances cannot be guaranteed or if fabrication tolerances have not been met.

7.3 Typical Sling Properties

The following table lists the properties of typical slings. It is taken from BS 1290 Specification for wire rope slings and sling legs for general lifting purposes and LRS Code for Lifting Appliances in a Marine Environment. Therefore the properties can only be strictly applied to slings constructed in accordance with these documents. All the properties are for single leg slings.

Table 3

Rope SWL Rope Diameter

Diameter (tonnes) (mm) (mm) $L..f'c.l 6 0.4 8 7 0.54 9 8 0.76 0·8 10 9 0.96 /•D

I

11 10 1.2

_J·s

I

12 11 1.4 l ·J;·

I

13 12 1.7

!·&I

14 13 2.0

_£.'1

I

16 14 2.3 "H ..

;·j

- v 18 16 3.0

,

'!"' } ~,

I

20 18 3.8

4 .,

I

22 20 4.7 ... d

··" l

~·

I

₂₄ 22 5.7

(,··::: I

26 24 6.8 ~:, _')cl _.

I

28 .'iii' I 5/t=G.L CvRE: _____/ ~t::-li- fft I '1

c:io

Typical Sling Properties

SWL Rope Diameter (tonnes) (mm) 0.8 8 1.0 10 1.3 12 1.5 14 1.8 16 2.1 18 2.5 20 3.3 22 4.1 24 5.1 26 6.2 28 7.4 32 8.6 36 10.0 40 Page 27 of 149 SWL (tonnes) 0.5 0.8 1 .1 1.6 2.1 2.6 3.2 3.9 4.7 5.5 6.3 8.3 10.5 13.0

(28)

Rope SWL

EM/039 Rev 3 1991

Rope Diameter SWL Rope Diameter SWL Diameter (tonnes) (mm) (tonnes) (mm) (tonnes)

(mm) 26 8.0 32 13.1 28 9.3 36 16.6 32 12.1 40 20.6 36 "15.4 44 24.9 40 19.0 48 29.6 44 23.0 52 34.9 48 27.5 56 40.4 52 32.0 60 46.3 56 37.3 60 42.8

It should be noted in using the tabulated figures in the Lloyds Register of Shipping that minimum breaking loads (MBL) are quoted.

7.4 Typical Shackle Properties

The Following tables Jist the properties of bow shackles. They are taken from the Crosby 'Green-Pin' Shackle Catalogue. These Tables are for guidance only. Current manufacturer's catalogues should be consulted for design purposes.

To reference the dimensions, consultation should be made of Figure 9 Typical Shackle Details.

Table 4 Dimensions and SWL of 'GREEN-PIN' Shackles

SWL W(mm)

I

B (mm) Db (mm) DP (mm) H (mm) Mass (kg) Tonnes 2.0 22 51 12.7 16 17 0.4 3.25 _.. 26 64 1q 19 20 0.8 4.75 31 76 19 22.2 23 1.2 6.5 36 83 22.2 25.4 26 1.8 8.5 43 95 25.4 28.6 29 2.6 9.5 47 108 28.6 31.8 32 4 12.25 51 115 31.8 35 35 5.3 13.75 57 133 35 38 38 7.5 17.25 60 146 38 41.3 41 9.3 25.5 74 178 44.5 50.8 51 15 35.5 83 197 50.8 57.2 57 21 50.75 105 254 63.5 69.9 70 42 76.25 127 330 76.2 82.5 83 65 101.5 146 381 88.9 95.3 98 113 132.0 165 432 101.6 108 108 160

(29)

22.7 73 139 31.75 83 152 45.3 105 210 68.0 127 271 90.7 135 308 136.0 159 254

7.5 Properties of Lifting Eyes and Lugs

44 51 64 76 89 140 51 57 70 83 95 11 54 15.4 64 23.5 76 46 83 81 102 120 114 154

These Tables are for guidance only. Current manufacturer's catalogues should be consulted for design purposes.

Table 6 Dimensions of Round and Oval Eyes

SWL Shank Round Oval

Tonnes d1 d2 d3 b g d4

J

e 1.0 M18 11 24 48 21 12

I

14 1.6 M22 14 30 58 26 16

I

18 2.0 M24 16 34 58 26 16 18 2.5 M27 18 39 72 32 21 23 3.2 M30 20 44 72 32 21 23 4.0 M33 22 48 94 40 26 28 5.0 M36 25 54 94 40

I

26 28 6.3 M42 27 60 108 45 29 32 8.0 M45 31 68 115 49 32 35 10.0 M52 35 76 125 54 36 39 12.5 M56 39 86 144 60 41 44 16.0 M64 163 66 46 49 20.0 M72x6 173 72 56 54 25.0 M76x6 192 80 56 59 32.0 M80 x 6 216 90 60 64 40.0 M90x6 240 100 66 70 50.0 M100 x 6 264 110 74 78 63.0 M110x6 290 120 84 89 80.0 M120 X 6 325 135 94 99 100.0 M130 X 6 360 150 105 111

NOTE: All dimensions are given in millimetres and are illustrated in Figure 10 Lifting Eyes and Lugs.

(30)

Table 7 SWL Shank a b Tonnes d 1 20 M72x6 475 400 25 M76x6 515 445 32 M80x6 565 500 40 M90x6 630 550 50 M100x6 675 600 63 M110x6 740 660 80 M120x6 815 725 100 M130x6 880 795 EM/039 Rev31991

Dimensions of Triangular Lifting Eyes

Top Side e f g h 48 95 66 95 51 108 72 108 55 120 79 120 59 133 86 133 64 146 94 146 71 150 104 150 78 158 115 158 86 178 127 178 Bottom j k 94 95 100 108 108 120 117 133 127 146 139 150 153 158 168 178

NOTE: All dimensions are given in millimetres and are illustrated in Figure 10 Lifting Eyes and Lugs.

Table 8 Dimensions of Lug Fittings

SWL Shank a b d2 d3 Tonnes d 1 1.0 M18 19 8 17 35 1.6 M22 23

I

11 21

I

45 1.0 M24

I

26 12 23 50 1.5 M27 29 13 25

I

55 3.2 M30 32 14 28 60 4.0 M33 35 15 31 65 5.0 M36 39 18 37 75 6.3 M42 45 20 40 85 8.0 M45 49 23 46 95 10.0 M52 58 26 50 110 12.5 M56 64 28 54 120 16.0 M64 70 30 62 130 20.0 M72x6 74 33 70 140 25.0 M76x6 80 35 74 150 32.0 M80x 6 90 40 82 170

7.6 Padeye Design Example

A Package of base weight 23 tonnes is to be installed on an offshore platform, with the plan form illustrated in Figure 11 Plan View of Package in Design Example. Four padeyes are to be designed accordingly to the criteria set out in the main text of this document.

(1) Establish Hook Load

'llh

Refer to Section 2.1 Hook Load (WH)

Base Weight = 23 tonnes (preliminary engineering estimate only available at this stage of design). ·

(31)

\ . ..

the characteristics of the vessel and crane which are to lift the package, and it is known that the package will NOT BE lifted from a supply boat in extreme design weather conditions.

The hool< weight \I'!TJ, =Fl. (W + VoTa.)

I

= 2.0 (23 + 4.6) = 55.20 tonnes, say 56 tonnes

(2) Establish Lifting Point Design Load 11'Ya Refer to Section 2.2 Lifting Point Design Load (WD)

Both pairs of diagonal padeyes (A and B, C and D) are designed to take 75 % of 'I/>T1.

Considering A and B: Refer to Figure 11 Plan View of Package in Design Example. 0. 75

VvJ,

= 42 tonnes

Padeye A takes: 2.2/4 x 42.0 tonnes

=

23.1 tonnes, say 24 tonnes (vertically).

Check padeye vertical load is ~ 2x static load. Refer to API Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms.

API check: 2 x static load= 2 x (23 + 4.6) x 0.75 x 2.2 + 4 = 22.7 tonnes A Wa = 24 tonnes to be used which exceeds 2 x static load o.k. for API check.

To minimise sling and shackle sizes, the sling angle (c)l) should be as large as possible. In this case, it is specified that the slings be long enough that c)l > 55° for each padeye. Therefore, conservatively,

Wa = 24 tonnes +sin 55°

=

29.3 tonnes (Pad eye and attachment design load).

Wa~

=

29.3 + D.A.F. (2.0) = 14.65 tonnes (Sling and Shackle design load). The components of Wa are:

Vertical Horizontal Lateral (0.05 Wd)

24 tonnes

24 tonnes +sin 55° = 16.80 tonnes 1.5 tonnes · oS t: N

&.

is the maximum value of Wa that any padeye is expected to carry. For conservatism, all the padeyes should be designed to accept these loads.

(3) Establish Sling and Shackle Sizes using Wa,_

The slings and shackles from->Table 4 Dimensions and SWL of 'Green-Pin' Shackles', SWL = 25.5 tonnes, mass= 15 kg each; 4 slings from 'Table: Typical Sling Properties', (Note: Designer MUST check sling and shackle manufacturers catalogues), 48 mm rope with steel core, SWL + 29.6 tonnes, length 5.5 m (to ensure

cp

~ 55°); Mass = 9.17 kg/m (50 kg each). Total weight if rigging= 4 (50+ 15) kg= 0.26 tonnes = 0.01 W.

Check clearance: tm = 178 - (11 0 + 48) = 20mm = 0.41 sling dia. <0.5 but accept.

NOTE: Shackle selection may be governed by clearance requirements rather than strength, so remember to check clearances.

(4) Material Selection (Referto Section 4.2 Material Selection)

.. /

Shell Guidelines Heavy Lifting Criteria

SHELL

ENGINEERING·

REFERENCE DOCUMENT

MANUAL:

GUIDELINES FOR LIFTING

POINTS AND HEAVY

LIFT

CRITERIA

Document Number : EM/039

Rev: 3

~ c~/r.;

fc·u .

UEOE/11 is the appointed Custodian of this document and must always be

consulted for advice on validity and currency

by

a user.

Custodian

Name:

Ref. Ind.:

Signature :

Date:

A WvanBEEK

UEOE/11

--~__q

lj/t/;;

Authorised

Name:

Ref. Ind.:·

Signature:

Date:

RMUNCASTER

·UEO;E

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CONTENTS

(lV'a)

(VY'a)

2.3

2.8.3

2.9.2

46

64

64

64

64

TABLES

74

74

74

77

77

57

58

59

145

146

147

148

PART 1 GUIDELINES FOR DESIGN FABRICATION AND INSPECTION OF LIFTING

POINTS

a

Tz

Wo.

WJ...

Wr

MBL

SF

=

=

'Na.

1.

p.O

=

=

=

("'Va)

Se~tion

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