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Internship Report

Erik Roke

MALIKAI PROJECT

Installation of a Tendon Leg Platform Offshore

I

Title Page

Internship Report

Installation of a Tendon Leg Platform Offshore

Name: Erik Roke

Student number: s1130641

Period: 05-01-2015 till 05-06-2015

Company: Heerema Marine Contractors

Kuala Lumpur

Malaysia

Supervisor: Rolf van Huffelen, Project Engineer

University: University of Twente

Faculty Engineering Technology

Department Applied Mechanics

Enschede

The Netherlands

Supervisor: Prof. dr. ir. André de Boer

II

Preface

This report was written in the context of a five months internship at Heerema Marine Contractors in

Kuala Lumpur, Malaysia. In this period I worked as a general engineer on different projects within the

project team which was in the preparation phase of a Tendon Leg Platform installation. André de Boer

provided supervision from the University of Twente.

I would like to thank both project engineers for the Malikai project, Rolf van Huffelen and Joost

Hazenbos, for the direct supervision during the internship and project manager Walter Wassenaar for

the overall supervision of the project. I also want to thank Dorien van de Belt as the internship

coordinator and André de Boer as the supervisor of the University of Twente.

Erik Roke

Date: September 2015

III

Management Summary

Heerema Marine Contractors (HMC) is together with the Malaysian Engineering Company IEV in the

preparation phase of installing Shell’s Malikai Tendon Leg Platform (TLP) by using one of Heerema’s own

vessels, the Aegir. This is a platform which floats on seawater and is kept in place by steel pipes

(tendons), connected between the platform and seabed. The downside of these tendons are fixed with

eight tendon driven piles. These tendons have a high axial stiffness so that there are no vertical

displacements of the platform possible due to the motions of the water. In the report, research is

covered about five new and improved equipment needed during the TLP installation. All designs were

presented and discussed with the client and the Heerema field specialists so that everything will work

and fit during the installation. The details of the designs, including the calculations and technical

drawings, are written in design reports reviewed by Heerema engineers. The reports contain the

following designs:

Guide Cone Seafastening Design

Guide cones are used to connected the tendons to the driven piles a couple of meters above the seabed.

To transport the cones, they are secured on a barge by welding four clip plates to the deck for each

cone. The acting stresses in this plate, weld and barge due transportation forces are within the

acceptable limits.

Rod Lock Mechanism

The tendons stand up in the water by clamping a tendon support buoy (TSB) around it. This one is

secured by a clamping system on the downside of the TSB. To lock this clamping system, a rod lock is

used as a mechanical lock which secures the clamping system till a force of 9.1 mT.

Bullnose Guide

The tendon porches of the TLP are used to fasten the tendons to the TLP. To guide the tendon into the

porches a guide is designed, the bullnose guide, strong enough to work with the pull in forces.

H-link Support Frame

Part of the installation is to pre-lay 8 mooring lines on the seabed which are build up with a chain on

both ends and a polyester rope in the middle. To connect the chain and polyester rope, an H-link is used

which is supported by a new designed H-link frame during the assembling of the mooring line.

ILT Modifications

The tendons will be upended from the barge by the crane of the Aegir. The rigging of the crane contains

an internal lift tool (ILT) which must be pulled inside the tendon. All components needed for the pull in

are reused and combined from different previous projects to get a suitable pull in procedure for Malikai.

All design reports, including the technical drawings, will be provided to the client so they can give their

comments and approval to use the equipment and installation procedures.

IV

Contents Title Page ........................................................................................................................................................ I

Preface .......................................................................................................................................................... II

Management Summary ............................................................................................................................... III

Symbols ......................................................................................................................................................... 1

Definitions ..................................................................................................................................................... 2

1 Introduction .......................................................................................................................................... 3

2 Assignment ............................................................................................................................................ 4

3 General Approach ................................................................................................................................. 5

3.1 Material ......................................................................................................................................... 5

3.2 Stress Criteria ................................................................................................................................ 5

3.3 Weld Criteria ................................................................................................................................. 6

3.4 Reporting Guidelines of Heerema................................................................................................. 6

4 Guide Cones Seafastening Design ......................................................................................................... 7

4.1 Location of Guide Cones ............................................................................................................... 8

4.2 Transportation Forces ................................................................................................................... 9

4.3 Forces on the Deck ...................................................................................................................... 10

4.4 Welding Stresses ......................................................................................................................... 12

4.5 Bearing Stresses .......................................................................................................................... 13

4.6 Conclusions ................................................................................................................................. 14

4.7 Recommendations ...................................................................................................................... 15

5 Rod Lock Mechanism .......................................................................................................................... 16

5.1 Rod Lock Design .......................................................................................................................... 17

5.2 Stress Calculations ...................................................................................................................... 19

5.2.1 Rods ..................................................................................................................................... 19

5.2.2 Front Plate ........................................................................................................................... 19

5.2.3 Collar ................................................................................................................................... 20

5.2.4 Connection of the Split Collar ............................................................................................. 20

5.3 Conclusions ................................................................................................................................. 22


6 Bullnose Guide .................................................................................................................................... 23

V

6.1 Problem Definition ...................................................................................................................... 24

6.2 Bullnose Guide Design ................................................................................................................ 25

6.3 Calculations ................................................................................................................................. 26

6.3.1 Bearing Stresses .................................................................................................................. 26

6.3.2 Maximum Pull Force ROV ................................................................................................... 28

6.4 Conclusions ................................................................................................................................. 28


7 H-Link Support Frame ......................................................................................................................... 30

7.1 H-Link Support Frame Design ..................................................................................................... 31

7.2 Transportation ............................................................................................................................ 31

7.3 Calculations ................................................................................................................................. 32

7.4 Conclusions ................................................................................................................................. 33


8 ILT Modifications ................................................................................................................................. 34

8.1 Assignment .................................................................................................................................. 35

8.2 Heerema’s Scope of Work .......................................................................................................... 35

8.3 IHC’s Scope of Work .................................................................................................................... 36

8.4 Conclusions ................................................................................................................................. 37


9 Conclusions ......................................................................................................................................... 40

10 Recommendations .......................................................................................................................... 41

11 Bibliography .................................................................................................................................... 42

Appendix A – Stresses in Weld .................................................................................................................... 43

Appendix B – Technical Drawing Guide Cones Seafastening ...................................................................... 44

Appendix C – Guide Cone Locations on the Barge Including Worst Case ................................................... 45

Appendix D – Transportation Forces of Guide Cone on Barge ................................................................... 46

Appendix E – Technical Drawings Rod Lock Mechanism ............................................................................ 48

Appendix F – Snag Points of the Bullnose ................................................................................................... 49

Appendix G – Technical Drawings Bullnose Guide...................................................................................... 50

Appendix H – Technical Drawings H-Link Support Frame ........................................................................... 51

Appendix I – Lift Design H-link Frame ......................................................................................................... 53

Appendix J – Padeye Capacity of the H-Link Frame .................................................................................... 55

1

Symbols

Symbol Definition Symbol Definition

𝑎 Weld size 𝜎⊥ Perpendicular stress 𝐴 Area 𝜏 Shear 𝛼 Mass distribution factor 𝜏𝑐 Combined shear stress 𝛼ℎ𝑒𝑎𝑣𝑒 Heave amplitude 𝜏|| Parallel shear stress

𝛼𝑝𝑖𝑡𝑐ℎ Pitch amplitude 𝜏⊥ Parallel shear stress

𝛼𝑟𝑜𝑙𝑙 Roll amplitude 𝑠 Second 𝑏 Width 𝑡 Thickness 𝐵 Breadth 𝑇 Cycle period °C Degrees Celsius 𝑊 Force 𝑑 Deck thickness 𝑊𝑑𝑒𝑠 Design weight 𝐷 Depth Wrig Rigging weight

𝐹 Force 𝑧𝐶𝑜𝑅 Height center of rotation Fdl Design load 𝑧𝐶𝑜𝐺 Height center of gravity Flp Lift point load

𝐹𝑣𝑙𝑝 Vertical lift point load

Frig Rigging load

𝐹𝑣𝑟𝑖𝑔 Vertical rigging load

𝐹ℎ Horizontal force 𝐹𝑣 Vertical force ℎ Height 𝐻 Heave Hdes Design hookload 𝐼 Moment of area 𝑘𝑔 Kilogram 𝐿 Length 𝐿𝑒 Thread engagement length 𝑀 Weight 𝑚𝑇 Metric ton 𝑚 Meter 𝑚𝑚 Millimeter 𝑀𝑃𝑎 Megapascal 𝑁 Newton 𝑃𝑣 Vertical impact force 𝑃ℎ Horizontal impact force σa Axial compression stress σb Bending stress σc Combined stress σp Bearing stress

σt Axial tension stress σy Yield stress

𝜎|| Parallel stress

2

Definitions

Abbreviation Definition

AISC API C.o.G. C.o.R. CT DAF EN EG GP HMC IEV ILT MLD QC ROV SC SW SWL TLP TSB U.C.

American Institute of Steel Construction American Petroleum Institute Center of gravity Center of rotation Constant tension Dynamic Amplification factor European Standards Engineering Guideline Green Pin Heerema Marine Contractors IEV Group SDN BHD Internal Lift Tool Mooring Line Deployment Quality Control Remotely Operated Vehicle Standard Criteria Spooler Winch Safe working load Tension leg platform Tendon support buoy Unity Check

3

1 Introduction

Currently, Heerema Marine Contractors (HMC) is together with the Malaysian Engineering Company IEV

in the preparation phase of installing Shell’s Malikai tendon leg platform (TLP). The engineering teams of

both companies are based in Kuala Lumpur, Malaysia. The TLP will be installed in 2016 located 110 km

off the shore of Sabah in the South China Sea.

A TLP is a platform which floats on seawater and is kept in place by using 500 m long steel pipes

(tendons). Eight tendons are used and they will be connected to the corners of the platform and the

seabed. The downside of these tendons are fixed by using eight tendon driven piles which are driven

into the seabed. The other side off the tendons is connected to the corner of the TLP after which it can

be deballast. These tendons have a relatively high axial stiffness so that there are no vertical

displacements of the platform possible due to the motions of the water and stays at exactly the same

position. This gives the advantage that the equipment used to dig up oil can be connected rigidly to the

TLP and seabed.

The installation of the TLP consists of the following activities:

Driving the piles into the seabed

Building up the tendons and connect it between the driven tendons and the TLP

Floating over the TLP and connect it to the tendons

IEV/HMC’s base scope of work consists of the following main activities:

Transportation and installation of eight foundation piles and 8 guide cones

Transportation and installation of eight tendon strings (and spares) and eight tendon support

buoys (TSB’s)

Wet tow (inshore, offshore and positioning) and installation of the TLP

Remove and return of all eight TSB’s to shore

Transportation and installation of 10 suction piles

Transportation and pre-lay of 10 mooring lines

In this report, research is covered about new and improved equipment that will be used during the

installation of the TLP. My task during the internship in to function as a general engineer and work on

different small projects/equipment by my own.

Frist of all, the different problems are defined and the general approach is provided to design new

equipment and solve problems (chapter 2 and 3). After that, the results and solutions are given of the

equipment I worked on during the internship (chapter 4 till 8). The conclusions and recommendations

are provided directly after each chapter. Then at the end of the report, the overall conclusion is given

and the next step in the design process after the design reports (given in this report) are ready (chapter

9 and 10).

4

2 Assignment

The preparations for the TLP installation is done by a project team in a 3 year window located in Kuala

Lumpur with different kind of engineers like structural engineers and installation engineers. All the

equipment used during the installation need to be designed and produced or reused from earlier

projects. Together with the installation manuals and installation specialists, the installation can be

completed. The assignment within the project team will be to work together with all the engineers

located in Kuala Lumpur at the office but also with the other employees working for Heerema at offices

all over the world.

Because of the 5 months internship duration, the personal assignment will be to design and modificate

five smaller parts so at the end of the internship the design reports will be finished and signed off by

Heerema engineers so it can be provided to the client. The parts are chosen such that the major subjects

Heerema is normally working on will be introduced. Hereafter, the subjects are summed with the

corresponding parts that suits the subject. The problem definition and assignment is described in detail

in the corresponding chapter with the design report. These design reports describe a total new design or

an improvement of the equipment which is used in previous projects done by Heerema.

Seafastening designs;

The way how equipment is fixed on a barge for transportation which can be done in combination with a

grillage.

- Guide Cone Seafastening Design (Chapter 4)

Structural or support frame designs;

Design and production of general support frames and installation equipment.

- H-link Support Frame (Chapter 7)

- Rod Lock Mechanism (Chapter 5)

- Bullnose Guide (Chapter 6)

Rigging designs;

Designs for lifting of equipment and make sure that the equipment contain lift points.

- H-link Support Frame (Chapter 7)

Reuse of equipment from previous projects;

For an efficient and quick working progress, equipment and installation ideas are reused from previous

projects which have a similar scope.

- ILT Modifications (Chapter 8)

5

3 General Approach

For all the equipment designed by Heerema, their own technology criteria are used, the “Standard

Criteria” (1). This describes design criteria and procedures for transportation, installation and

mechanical designs which is indicated with the abbreviation “SC” in this report in combination with the

number of the corresponding criteria. Some of those criteria are applicable for all the designs in this

report like material, stress and weld criteria as will be discussed in section 3.1 till 3.3. All other used

criteria are specific for the design and are indicated in the report when this is used.

If it is possible, all calculations are done by hand to finish design reports as quick as possible and prove

the design is reliable. For more complex designs computer programs may be useful.

The way of reporting within the Heerema guidelines for design and installation reports are given in

section 3.4.

3.1 Material The most common material used for the designs in this report is steel. The following specific steel is

used: Specification 001 welding and fabrication of structural steel Type V – Primary Steel with Charpy-V

impact tested at -20 °C. The yield stresses that suits this type of steel for different thicknesses are given

in Table 1. (2)

Item Thickness t [mm] Type Minimum Yield Strength 𝝈𝒚 [MPa]

Steel plate 0 < 𝑡 ≤ 16 Type V 355



Steel plate 40 < 𝑡 ≤ 63 Type V 335 Table 1: Yield stresses steel plates type V for different thicknesses

The minimum plate thickness that is normally used in the offshore industry is 10 mm.

The specification for the materials will be provided on all the drawings made by Heerema. If any other

material is used in this report the specification and yield stresses will be mentioned separately.

3.2 Stress Criteria For all the calculations in this report, the stress acting in a component will be checked against the yield

stress 𝜎𝑦 with the safety factor as in given in Table 2. Heerema uses these factors as a standard for

offshore purposes according to AISC (3) and API (4). The stress in a component will be tested and

expressed by the use of a Unity Check (U.C.):

𝑈. 𝐶. =𝑠𝑡𝑟𝑒𝑠𝑠

𝑓𝑎𝑐𝑡𝑜𝑟 ∗ 𝜎𝑦≤ 1.0

6

Axial compression 𝜎𝑎 0.60 ∗ 𝜎𝑦

Axial tension 𝜎𝑡 0.60 ∗ 𝜎𝑦

Bending 𝜎𝑏 0.66 ∗ 𝜎𝑦

Shear 𝜏 0.40 ∗ 𝜎𝑦

Combined 𝜎𝑐 0.66 ∗ 𝜎𝑦

Bearing 𝜎𝑝 0.90 ∗ 𝜎𝑦 Table 2: Allowable stress factor

When the shear and bending stress gives a U.C. close to 1.0, it would be useful to combine the shear and

bending stress with the following Von Mises criterion:

𝜎𝑐 = √𝜎2 + 3𝜏2

and check the U.C. for the combined stress. After all the stress evaluations, the U.C. is shown as prove

for the fact that the stress satisfy the criteria.

3.3 Weld Criteria All stresses in the welds for the new designed equipment should be checked according the unity checks.

These stresses are calculated in the design procedure and provided in the design reports. The way how

these stresses are calculated is given in Appendix A. In this report, after a weld calculation, only the

stress and unity check is shown and the number which indicates the calculation type that is used as is

given in Appendix A. The stresses are combined according:

𝜏𝑐 = √∑𝜏∥2 + ∑𝜏⊥

2

𝜎𝑐 = √∑𝜎∥2 + ∑𝜎⊥

2

After that, the stress is checked if it satisfy the stress criteria as is given in section 3.2.

When the equipment are produced, the welds should be inspected by the subcontractor according to

the inspection category on the drawings. This indicates the type of inspection and the percentage of

welds that should be checked. All welds must be visual checked and depending on the inspection

category, an additional inspection like radiographic, ultrasonic or magnetic is applied on a certain

percentage of the welds as can be found in the “Specification for Materials” document for the Malikai

project (2).

3.4 Reporting Guidelines of Heerema All new designs and procedures made by an engineer of Heerema should be written in a standard

Heerema report so it can be checked by other engineers. When all the engineers agree it can be signed

off after which it will be send to the client so they can give their comments.

In this report, a summary of the Heerema design reports with the corresponding results are shown.

Detailed calculations can be found in the original design reports from Heerema which are signed off by

Heerema engineers and ready to send to the client for comments.

7

4 Guide Cones Seafastening Design

When the tendon bottom sections are sucked into the seabed the anode carriers (guide cones) are

connected to these tendons. Thereafter the rest of the tendons including the tendon top section can be

connected at once to the guide cones. This chapter describes the seafastening which restricts the guide

cones from movement during the transportation on the MICLYN 3316 cargo barge due all the transport

forces derived from roll and pitch movements. In total 8 guide cones needs to be transported from the

coast to the location where the TLP will be installed. An example of these guide cones stored on a barge

can be found in Figure 1. To secure these guide cones on deck, 4 steel clip plates will be welded to the

deck to prevent each guide cone from sliding and rotating so there are 32 clip plates needed in total.

First will be determent which guide cone results in the highest forces on the deck due to the motions of

the barge (worst case). Then the stresses on the clip plates and the barge are calculated, caused by the

transportation forces. The clip plates must satisfy the following requirements:

- Make as less damage as possible to the guide cones as possible.

- Easy and quick removable when the guide cones must be lifted of the barge which is happening

on sea with a lot of motions.

The clip plates can be seen in detail in the technical drawing in Appendix B.

Figure 1: Guide Cone stored in a barge without seafastening

For the transportation forces, the origin of the Cartesian coordinate system used to know the force

equilibrium is given in Figure 2. Angles and moments are according to the Right Hand Rule.

8

Figure 2: Cartesian coordinate system used for calculations including the angles and moments (1)

C.o.G.: Center of gravity of the cargo.

C.o.R.: Center of rotation of the barge. The center of rotation is on water level: 𝑧𝐶𝑜𝑅 = 𝑚𝑒𝑎𝑛𝑑𝑟𝑎𝑓𝑡

There are 3 movements of the barge considered in the calculations:

- Pitch : the rotation of the barge about the lateral axis

- Roll : the rotation of the barge about the longitudinal axis

- Heave : the linear vertical up and down motion of the barge

The force of the guide cone on the barge due to these motions are considered for the static and

dynamic case after which they are combined.

4.1 Location of Guide Cones The guide cones are located on the barge such that the C.o.G. of the cones is above the location where

the transverse webframe and bulkhead cross the center longitudinal bulkhead (the roll axis). These

bulkheads are upright walls within the barge. Because of this, the seafastening clip plates are on top

these webframes and bulkheads so the strongest parts of the barge are used to guide the resulting

transportation forces.

The C.o.G. of the guide cone is located in the middle at a height of 69.11 inch (1755 mm) as can be seen

on the drawing of the seafastening in Appendix B.

For a conservative calculation, the stresses of seafastening design are determined for the guide cone

which is located most far away from the lateral axis (pitch axis). This one gives in the highest vertical

transportation forces on the deck when the barge rotates about this axis. This is the cone closest to the

stern, see Figure 3. A detailed drawing of the barge with all the guide cone locations and the worst case

position can be seen in Appendix C.

9

Figure 3: Location of the guide cone (marked grey) which gives in the highest force on the MICLYN barge (dimensions in

[mm])

4.2 Transportation Forces For the guide cone closest to the stern, the transportation force for this one due to the motions of the

barge will be calculated.

Barge information (5):

Dimensions barge:

Length Overall: L = 100.58 m

Breadth: B = 30.48 m

Depth: D = 6.1 m

Deck thickness d = 20 mm

Under deck welding size a = 8 mm, due to wear and rust 4 mm is used in the calculations

as a safety factor

Yields stress: 𝜎𝑦 = 235 𝑁𝑚𝑚2⁄

Motion criteria for large cargo barges (L>76 m and B>23 m) according to the Nobel Denton criteria (6):

Full cycle period: T = 10 s (full cycle period)

Roll amplitude: 𝛼𝑟𝑜𝑙𝑙 = 20° (single amplitude angle)

Pitch amplitude: 𝛼𝑝𝑖𝑡𝑐ℎ = 12.5° (single amplitude angle)

Heave: H = 5 m (5 m heave at a 10 s cycle period accounts for a vertical

acceleration of 0.2 g) (single amplitude)

Accelerations of the cargo (angles in [rad]):

�̈�𝑟𝑜𝑙𝑙 = (2𝜋

𝑇)

2

∗ 𝛼𝑟𝑜𝑙𝑙 = (2𝜋

10)

2

∗ 0.3491 = 0.1377 𝑟𝑎𝑑𝑠2⁄

100580

30480 7320

𝑦 𝑥

𝑆𝑡𝑒𝑟𝑛

𝐵𝑜𝑤

𝑥

𝑧 6100

1755

(𝑁𝑜𝑡 𝑇𝑜 𝑆𝑐𝑎𝑙𝑒)

10

�̈�𝑝𝑖𝑡𝑐ℎ = (2𝜋

𝑇)

2

∗ 𝛼𝑝𝑖𝑡𝑐ℎ = (2𝜋

10)

2

∗ 0.2182 = 0.0861 𝑟𝑎𝑑𝑠2⁄

�̈�ℎ𝑒𝑎𝑣𝑒 = (2𝜋

𝑇)

2

∗ 𝐻 = (2𝜋

10)

2

∗ 5 = 1.97 𝑚𝑠2⁄

Cargo (guide cone) information:

Weight cargo: M = 11.5 mT → W = 113 kN

Width cargo: b = 3.58 m

Height cargo: h = 3.33 m

Length cargo: l = 3.58 m

Mass distribution factor: α = 1.5 (1.1≤ α ≤1.5)

Mass moment of inertia of cargo:

Roll axis: 𝑀0𝐼𝑥 =1

12∗ 𝛼 ∗ 𝑀 ∗ (ℎ2 + 𝑏2) = 34.36 𝑇𝑚2

Pitch axis: 𝑀0𝐼𝑦 =1

12∗ 𝛼 ∗ 𝑀 ∗ (ℎ2 + 𝑙2) = 34.36 𝑇𝑚2

From the barge and cargo information result the static, dynamic and heave forces for the case that the

barge is going to roll, pitch or heave. From all the cases follows a horizontal, vertical and moment force

which is shown in detail in Appendix D. These forces can be combined to get the resulting force of the

cargo on the deck of the barge as given in Table 3. Their work point is the C.o.G. of the cargo.

Positive Heave Negative Heave

Roll to Fv -128 [kN] -85 [kN] starboard Fh -521 [kN] -36 [kN]

Moment 51 [kNm] 5 [kNm]

Roll to Fv -128 [kN] -85 [kN] port side Fh -52 [kN] -36 [kN] Moment -5 [kNm] -5 [kNm]

Pitch to Fv -1751 [kN] -131 [kN]

stern Fh -33 [kN] -23 [kN] Moment -3 [kNm] -3 [kNm]

Pitch to Fv -90 [kN] -461 [kN]

bow Fh 33 [kN] 23 [kN] Moment 3 [kNm] 3 [kNm]

Table 3: Resulting forces of the cargo exerted on the barge for all different motions

The marked extreme forces are used for the total force of the guide cone acting on one point on the

deck and clip plate as is described hereafter.

4.3 Forces on the Deck The goal is to calculate the resulting maximum force on one point of the barge and one clip plate due to

the horizontal, vertical and moment forces of the guide cone. Horizontal forces will always act on the

11

clip plates and vertical forces always on the barge. When considering a rotation point for the guide cone,

the horizontal force (𝐹ℎ) and moment force (𝑀) result in a rotation of the guide cone, however the

vertical force (𝐹𝑣) prevents it from rotating, see Figure 4. Here is a rotation of the guide cone to the right

is shown. 𝐹𝑣 maximal and 𝐹𝑣 minimal is considered for the maximal and minimal downforce on the deck

where the latter tells something about the rotation which is explained hereafter.

Figure 4: Forces on the deck and clip plates resulting from the vertical, horizontal and moment forces of the guide cone

(dimensions in [mm])

The forces of the guide cone, 𝐹𝑣, 𝐹ℎ and 𝑀, are decomposed in their vertical components acting on one

point on the deck respectively, 𝐹𝑣𝑣, 𝐹𝑣ℎ and 𝐹𝑣𝑚.

If the guide cone is rotating (the vertical force it too low to prevent that) there are two uplift forces, 𝐹𝑣ℎ

and 𝐹𝑣𝑚, which are guided into the clip, this case is shown on the left side in Figure 4. If the guide cone is

not rotating the vertical force 𝐹𝑣𝑣 cancels 𝐹𝑣𝑚 and 𝐹𝑣ℎ so there is only a downforce on the deck and a

horizontal force on the clip plate left.

For the vertical force 𝐹𝑣𝑣 on the deck, resulting from the minimum and maximum force of the cargo 𝐹𝑣,

is assumed that this can be divided over 4 points. This means that the guide cone will always rest with at

least 4 points on the deck.

𝑀𝑎𝑥 𝐹𝑣𝑣 =𝐹𝑣

4=

175

4= 43.8 𝑘𝑁

𝑀𝑖𝑛 𝐹𝑣𝑣 =𝐹𝑣

4=

46

4= 11.5 𝑘𝑁

𝐹𝑣𝑚 =𝑀

𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝐶𝑜𝑛𝑒=

5 ∗ 103

3581= 1.4 𝑘𝑁

𝐹𝑣ℎ =(𝐹ℎ ∗ 𝐻𝑒𝑖𝑔ℎ𝑡 𝐶𝑂𝐺 𝐶𝑜𝑛𝑒)

𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝐶𝑜𝑛𝑒=

52 ∗ 1689

3581= 24.5 𝑘𝑁

By summing all 3 vertical forces, the maximum total force of the guide cone on one local point on the

deck is known. This is the situation on the right side on Figure 4.

𝐹ℎ =

52 𝑘𝑁

𝑀 =

5 𝑘𝑁𝑚

𝑀𝑎𝑥 𝐹𝑣 = 175 𝑘𝑁

𝑀𝑖𝑛 𝐹𝑣 = 46 𝑘𝑁

𝐺𝑢𝑖𝑑𝑒 𝐶𝑜𝑛𝑒

3581

3987

178

1689

𝐹𝑣𝑣 𝐹𝑣𝑚

𝐹𝑣ℎ

𝐹𝑣𝑣 𝐹𝑣𝑚

𝐹𝑣ℎ

𝐵𝑎𝑟𝑔𝑒 𝐷𝑒𝑐𝑘

𝐶𝑙𝑖𝑝 𝑃𝑙𝑎𝑡𝑒

(𝑁𝑜𝑡 𝑇𝑜 𝑆𝑐𝑎𝑙𝑒)

𝑅𝑜𝑡𝑎𝑡𝑖𝑜𝑛 𝑝𝑜𝑖𝑛𝑡

12

𝑀𝑎𝑥 ↓ = 𝑀𝑎𝑥 𝐹𝑣 + 𝐹𝑣𝑚 + 𝐹𝑣ℎ = 69.7 𝑘𝑁

To calculate the minimum force of the guide cone on the deck is useful to know if there is any uplift. The

lowest vertical force of Table 3 is used. When this vertical force (min 𝐹𝑉) is lower than the resulting

vertical force of the moment (𝐹𝑣𝑚) and horizontal force (𝐹𝑣ℎ), the guide cone will rotate on deck and

results in an uplift. This is the situation on the left side on Figure 26.

𝑀𝑖𝑛 ↓ = Min 𝐹𝑉 − 𝐹𝑣𝑚 − 𝐹𝑣ℎ = −14.4 𝑘𝑁

Because this force is lower than zero, it results in an uplift force on the clip plate of approximately 15 kN.

The other incoming force on the clip plate is the horizontal force 𝐹ℎ of 52 kN.

4.4 Welding Stresses The thickness of the clip plate used is 16 mm. This plate is welded on both sides to the barge deck with a

6 mm weld. The effective weld thickness becomes:

2 ∗ 6 ∗1

√2= 8.5 𝑚𝑚

Because the effective thickness of the weld is lower than the thickness of the plate, the weld will fail

earlier due to the forces of the guide cone. This is why the stress calculations are only done for the weld

and not for the clip plate.

Two cases are considered, the maximum and the minimum down force of the guide cone on the deck.

Due the forces on the clip plates, the strength of the weld which connects it to the deck but also the

barge under deck weld (connects the barge to the bulkheads) needs to be checked. When the force of

the clip plate reaches the under deck weld, it goes first through the 20 mm thickness deck plate. Due to

the thickness of the deck, load spread occurs and the effective under deck weld becomes longer than

the length of the weld used for the clip plate. The ratio of the load spread to the deck thickness is: 1: 2.5.

The effective length 𝑙 becomes (see Figure 5):

𝑙 = 178 + 2 ∗ 2.5 ∗ 20 = 278 𝑚𝑚

This is checked in section 0.

Weld Clip Plate

The effect of the guide cone in case of the minimum and maximum downforce on the clip plate

regarding the forces is shown in Figure 5. The resulting stresses in the weld are considered separately

because they cannot occur at the same time. In case of the minimum downforce, an uplift force of 15 kN

(marked green in Figure 5) acts on the clip plate which is the case on the left side in Figure 4. In case of

13

the maximum down force, a horizontal force of 52 kN is acting on the clip plate (marked red in Figure 5)

which is the case on the right side of Figure 4.

Figure 5: Free body diagram of the clip plate in case of a minimum and maximum down force of the guide cone which results

in an uplift force and a horizontal force, respectively green and red. (dimensions in [mm])

After a stress evaluation for the weld of the clip plate it follows that the maximum down force gives the

highest stress. The horizontal incoming force results in a shear force with a corresponding parallel shear

stress and a moment force with a corresponding perpendicular shear and bending stress in the weld.

After a combination of the shear and bending stress follows:

𝜏𝑐 = √𝜏∥2 + 𝜏⊥

2 = 71.3 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

71.3

0.4 ∗ 235= 0.76 (𝑐𝑎𝑠𝑒 1 𝑎𝑛𝑑 4, 𝐴𝑝𝑝 𝐴)

𝜎𝑐 = 𝜎⊥ = 62.4 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

62.4

0.66 ∗ 235= 0.40 (𝑐𝑎𝑠𝑒 4, 𝐴𝑝𝑝 𝐴)

Barge Underdeck Weld

The location and effective weld length of the underdeck weld can be found in Figure 5 with a weld size

𝑎 = 4 𝑚𝑚 (5). A moment force is acting on this weld which is maximum for the maximum downforce

case. The perpendicular shear stress gives the highest U.C. which is equal to:

𝜏𝑐 = 𝜏⊥ = 48.44 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

48.44

0.4 ∗ 235= 0.52 (𝑐𝑎𝑠𝑒 4, 𝐴𝑝𝑝 𝐴)

4.5 Bearing Stresses The bearing stress in the webframe which is responsible for the stiffness of the barge will be checked in

this section.

6

6 152

178

290

𝑙

𝐿𝑜𝑎𝑑 𝑠𝑝𝑟𝑒𝑎𝑑

𝑜𝑓 1: 2.5

52 𝑘𝑁

76

20

𝐵𝑎𝑟𝑔𝑒 𝑑𝑒𝑐𝑘

15 𝑘𝑁

234

𝐵𝑎𝑟𝑔𝑒 𝑢𝑛𝑑𝑒𝑟𝑑𝑒𝑐𝑘

𝑤𝑒𝑙𝑑 𝑙𝑜𝑐𝑎𝑡𝑖𝑜𝑛

14

Figure 6: Bearing stress of the guide cone on webframe

The maximum downforce on the deck is 𝐹ℎ = 70 𝑘𝑁. This force is guided through the deck and ends up

in a stress on the webframe (thickness is 10 mm (5)) with an effective length of 𝑙 = 125 𝑚𝑚, so the

stress area on the webframe is:

10 × 125 = 1250 𝑚𝑚2

Bearing stress:

𝜎 =𝐹ℎ

𝐴𝑟𝑒𝑎= 56 𝑁

𝑚𝑚2⁄ → 𝑈. 𝐶. = 56

0.9 ∗ 235= 0.26

4.6 Conclusions The seafastening design consists of 4 clip plates for each guide cone which are welded to the deck. The

guide cones are located on the barge such that the C.o.G. of the cones is above the location where the

transverse web frame and bulkhead cross the center longitudinal bulkhead. In this way the strongest

parts of the barge are used to guide the forces of the guide cones and clip plates. To make sure the clip

plates make less damage as possible to the guide cones, the plates are not fixed to the guide cone with a

weld.

Because the plates will only be welded to the deck on both sides, they can easily be cut and removed

offshore when the guide cones are needed to be lifted of the barge.

To make sure the plates and barge are strong enough, the stresses in the clip plates, weld and barge

frames are checked for the incoming forces of the guide cones due to the motion of the barge for the

most critical guide cone. All used items within the calculations are suitable for this offshore

transportation purpose and all values are within acceptable limits as can be seen in Table 4 where the

U.C. are given. A technical drawing of the clip plates and the drawing for the locations of the guide cones

on the bare are given in Appendix B and Appendix C.

𝐿𝑜𝑎𝑑 𝑠𝑝𝑟𝑒𝑎𝑑

𝑜𝑓 1: 2.5

𝐵𝑎𝑟𝑔𝑒 𝑑𝑒𝑐𝑘

𝑙

𝐺𝑢𝑖𝑑𝑒 𝐶𝑜𝑛𝑒

25

20

𝑊𝑒𝑏𝑓𝑟𝑎𝑚𝑒 𝑤ℎ𝑖𝑐ℎ 𝑠𝑢𝑝𝑝𝑜𝑟𝑡𝑠

𝑡ℎ𝑒 𝑏𝑎𝑟𝑟𝑔𝑒 𝑑𝑒𝑐𝑘 𝑤𝑖𝑡ℎ 𝑎 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 𝑜𝑓 10 𝑚𝑚 (5)

15

Item Load case U.C. Reference

Welding Seafastening Clip Plate 0.76 0 Welding Barge Underdeck 0.52 0 Bearing stress 0.26 4.5 Table 4: Unity Checks for the guide cone seafastening design

4.7 Recommendations In Table 3 are 8 different scenarios given for the possible motions of the barge. For each scenario the

minimum and maximum force of the guide cone on the barge should be calculated to know the worst

case scenario. For the calculations done in this chapter, the highest forces from Table 3 are used for the

calculations so the scenarios are combined to get a conservative and much shorter calculation. In reality

only 1 scenario is possible at ones.

Another scenario which is not considered, is when the barge is going to pitch and roll at the same time.

This motion will not lead to the extreme motions of the barge, but can also be checked for a complete

stress evaluation.

For now, it is assumed that without a weld, so a loose connection between the guide cone and the clip

plates, there will be no serious damage to the cones. If this is the case in reality, the surface of the clip

plate should be made soft or rounded to prevent that.

The barge used in the calculations is an example barge and is similar to the one that will be used in the

Malikai project. The data of the actual barge will be provided when the barge is nominated after which

the ballast of the barge can also be checked.

16

5 Rod Lock Mechanism

When the bottom sections of the tendon piles are sucked into the seabed and the anode carriers (guide

cones) are connected on top of these piles, the rest of the tendons including the tendon top section can

be connected to this anode carriers. When the tendons are connected they are in the free standing

phase before the TLP is attached to the tendons and will be supported by the tendon support buoys

(TSB’s) which are clamped to the tendon top sections on deck, see Figure 7. These TSB’s are fixed with a

clamping system on the downside and a centralizer on the top side. Each clamping system on the

downside will be closed by the use of 4 reaction tubes with a rod inside to secure the reaction tube by

pulling these rods inside. These rods stay inside due to a secure lock in the hydraulic system which pulls

the rods inside and also presses them out. Due to the policies of the client, there is also a mechanical

lock needed for these rods. These mechanical rod locks prevent the rods inside the reaction tube to

move outwards and unlock the TSB clamping system when the TSB’s are clamped on the tendons. In

previous projects, there was already a rod lock designed, but this one was very heavy (about 80 kg) and

also difficult to connect it on deck and release it underwater by the remotely operated vehicle (ROV).

Figure 7: Left: TSB clamped around the top tendon with the centralizer and clamping system. Right: reaction tube of the

clamping system on the downside of the TSB

For the Malikai project a new design for this rod lock mechanism is made, which will be used on the

TSB’s. This rod lock should at least satisfy the following requirements:

- Lower than 23 kg so it can be lifted and connected by 1 person on deck (7)

- Easy to remove by the ROV underwater

- Secure the rod of the reaction tube till a maximum force of 20 kips (9.1 mT)

- As cheap as possible

17

In total 32 rod locks will be installed on 8 TSB’s (4 rod locks each) as can be seen in Figure 8 where the

rod locks are fixed to the reaction tube. Be aware that this are the rod locks of previous project and will

be redesigned in this chapter.

Figure 8: Clamping system on the downside of the TSB where the four reaction tubes can be seen. Each tube contains a rod

lock from previous project.

5.1 Rod Lock Design The new rod lock design is shown in Figure 9 including the reaction tube (dotted lines). A detailed

technical drawing with all the dimensions is given in Appendix E. The exact dimensions of the reaction

tube where not known because the client didn’t provide all the drawings of the TSB. During a visit at the

yard MMHE in Johor Bahru Malaysia, where the TLP is produced and the TSB’s are stored, the reaction

tubes are measured by hand.

18

Figure 9: Rod lock mechanism design fix to the reaction tube and rod of the TSB

Connection

The split collar will be installed on the yard. Meanwhile the rods, front plate, nuts and lanyard between

two connection points will be installed on deck. All the parts are connected with bolts and nuts and the

weight of each separate part is below 23 kg (see section 5.3), so this can easily be assembled by one

person. The front plate will be connected such that the rod inside the reaction tube penetrates the front

plate for 10 mm.

Release

After the TLP is attached to all 8 tendons, the TBS’s can be removed one by one from the tendon top

sections. First the rod locks need to be removed before the locking system can be opened. The rod locks

are released by using the ROV with a wire cutter to cut the 2 rods of the rod lock. To give a clear spot on

the camera of the ROV, the rods are marked yellow so the people on deck can see where to cut. This

wire cutter can cut through the 20 mm diameter rods, but needs a clearance of 80 mm to the

environment. This is incorporated by designing the rod lock such that the distance between the rods of

the rod lock and the rod of the reaction tube is minimal 80 mm. When both rods of the rod lock are cut,

the front plate, including 2 pieces of rod, drops off the clamping system. The pieces of rod stay

connected to the front plate due to the nuts. Due to a lanyard between the split collar (which is still

connected to the reaction tube) and the steel front plate, the front plate stays connected to the TSB.

𝑅𝑜𝑑𝑠

𝐹𝑟𝑜𝑛𝑡 𝑃𝑙𝑎𝑡𝑒

𝑆𝑝𝑙𝑖𝑡 𝐶𝑜𝑙𝑙𝑎𝑟

𝐿𝑎𝑛𝑦𝑎𝑟𝑑

𝑐𝑜𝑛𝑛𝑒𝑐𝑡𝑖𝑜𝑛

𝑅𝑒𝑎𝑐𝑡𝑖𝑜𝑛

𝑇𝑢𝑏𝑒

𝑅𝑜𝑑 𝐼𝑛𝑠𝑖𝑑𝑒

𝑅𝑒𝑎𝑐𝑡𝑖𝑜𝑛

𝑇𝑢𝑏𝑒

19

5.2 Stress Calculations All parts, bolts and welds will be checked for the stress when a force of 20 kips is applied on the rod lock

by the reaction tube.

For the rod lock, all the occurring stresses due to the reaction tube should be checked against the yield

stress. The Rod Lock is designed to secure the clamping system with a maximum force of 20 kips (𝐹 =

9.1 𝑚𝑇). This force is acting on the front plate which is supported by 2 full threaded metric M20 rods.

The force distribution is assumed to be 40% - 60% for the whole mechanism as a safety factor.

Figure 10: Force distribution in the rod lock

5.2.1 Rods

The stresses in one rod is checked for 60% of the total force (see Figure 10) and also the screw thread is

considered if it is able to handle the force. The actual shear surface of a M20 rod is 245 𝑚𝑚2. The class

8.8 rod which is used is comparable to an A325 class bolts with an allowable stress of 44 kips

(303 𝑁𝑚𝑚2⁄ ) by AISC table J3.2 (3) and gives for the resulting tensile stress:

𝜎 =0.6 ∗ 89271

245= 218.6 𝑁

𝑚𝑚2⁄ → 𝑈. 𝐶. =218.6

303= 0.72

Screw thread

M20 metric thread:

𝑝𝑖𝑡𝑐ℎ 𝑝 = 2.5 𝑚𝑚

𝑏𝑎𝑠𝑖𝑐 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝐷 = 20 𝑚𝑚

Tensile stress area of male screw:

𝐴𝑡 =𝜋

4(𝐷 − 0.938194 ∗ 2.5)2 = 245 𝑚𝑚2

The minimum length of the thread engagement is assumed to be equal to the diameter of the rod: 𝐿𝑒 =

20 𝑚𝑚. Thread shear area:

𝐴𝑠𝑠 = 0.5 ∗ 𝜋 ∗ (𝐷 − 0.64952 ∗ 𝑝) ∗ 𝐿𝑒 = 577 𝑚𝑚2

To ensure the rod fails before the thread strips, the thread shear area (𝐴𝑠𝑠) is at least two times the

tensile stress area.

𝑈. 𝐶. =2 ∗ 𝐴𝑡

𝐴𝑠𝑠=

2 ∗ 245

577= 0.85

5.2.2 Front Plate

The stress in the front plate is calculated as a simply supported beam with a uniform distributed load.

Due to the thickness of the front plate, there is a force distribution from the location where the force is

𝐹

0.6𝐹

0.4𝐹

𝐹

0.6𝐹

0.4𝐹

20

acting to the neutral line, by Heerema’s specifications this distribution relation is 1: 2.5 compared to the

thickness so the load spread is (Figure 11):

𝑙 = 66 + 2 ∗ 2.5 ∗ 12.5 = 128.5 𝑚𝑚

Figure 11: Rod Lock front plate load distribution

Because this length exceeds the width of the plate, 110 mm is used for the calculation.

After a stress calculation for the simply supported beam the combined stress consisting of the shear and

bending stress gives a unity check of:

𝜎𝑐 = √𝜎2 + 3𝜏2 = √207.82 + 3 ∗ 54.32 = 227.8 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

227.8

0.66 ∗ 345= 1.00

5.2.3 Collar

Also the stress in the collar is calculated as a simply supported beam with two support points at the

location of the teeth of the reaction tube. At these point, the width 𝑏 is taken as the width for the beam

and is equal to 262 mm. After a stress calculation, the combined stress consisting of the shear and

bending stress gives a unity check of:

𝜎𝑐 = √𝜎2 + 3𝜏2 = √59.32 + 3 ∗ 10.22 = 61.9 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

61.9

0.66 ∗ 345= 0.27

5.2.4 Connection of the Split Collar

The two collar halves are fixed by the use of two half circular shells welded perpendicular to the collar

halves. The end part of the shell is bend on both ends to create a flat surface for a M24 bolt connection

as can be seen in Figure 9. There is a clearance of 2 mm between both flat surfaces and shows that no

pretension bolts are needed, because the rotation point will be located at the point where the collar

halves touch each other, see Appendix E for specific drawing. The bending in the shell and the weld

needs a stress evaluation.

Bending shell halves

The shells are simplified as a beam totally supported at one side and a force of two M24 bolts on the

other side. The moment of area for this geometry is:

𝐼 = 3.596 ∗ 106 𝑚𝑚4

After a stress calculation for a totally supported beam on one side, the combined stress consisting of the

shear and bending stress gives a unity check of:

𝐿𝑜𝑎𝑑 𝑠𝑝𝑟𝑒𝑎𝑑 𝑜𝑓 1: 2.5

𝑙

66

45

110

12.5

21

𝜎𝑐 = √𝜎2 + 3𝜏2 = √140.42 + 3 ∗ 87.72 = 206.8 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

206.8

0.66 ∗ 355= 0.88

Weld

The circular weld (size: 10 mm) of the shell is considered as the only supporting weld, so the part of the

flat end is left out. As a simplification, the circular weld is transformed to a rectangular weld as can be

seen in Figure 12. This one is within the circular weld to get a conservative simplification.

Figure 12: Simplification of the circular weld to a rectangular weld

The new weld length is equal to:

𝐿 = √852 + 852 = 120 𝑚𝑚

The force acts perpendicular on two plates of the new geometry and parallel on the other two plates.

After a stress evaluation, the plates with a force in the perpendicular direction gives the highest stress as

is equal to:

𝜏𝑐 = ∑𝜏⊥ = 105.3 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

105.3

0.4 ∗ 345= 0.76 (𝑐𝑎𝑠𝑒 2 𝑎𝑛𝑑 𝑐𝑎𝑠𝑒 5, 𝐴𝑝𝑝 𝐴)

𝜎𝑐 = ∑𝜎⊥ = 105.3 𝑁𝑚𝑚2⁄ → 𝑈. 𝐶. =

105.3

0.66 ∗ 345= 0.46 (𝑐𝑎𝑠𝑒 2 𝑎𝑛𝑑 𝑐𝑎𝑠𝑒 5, 𝐴𝑝𝑝 𝐴)

Bolts

The stress acting in one of the two M24 bolt due to the rotation of the collar is 60% of the total force as

a safety factor which is equal to 155585 𝑁. The actual shear surface of a M24 bolt is 352 𝑚𝑚2. The

class 8.8 rod which is used, is comparable to an A325 class bolts with an allowable stress of 44 kips

(303 𝑁𝑚𝑚2⁄ ) by AISC table J3.2 (3) and gives for the resulting tensile stress:

𝜎 =0.6 ∗ 155585

352= 265.2 𝑁

𝑚𝑚2⁄ → 𝑈. 𝐶. =265.2

303= 0.88

𝐿

85 85

10 10

𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝑐𝑖𝑟𝑐𝑢𝑙𝑎𝑟

𝑤𝑒𝑙𝑑

𝑆𝑖𝑚𝑝𝑙𝑖𝑓𝑖𝑒𝑑 𝑟𝑒𝑐𝑡𝑎𝑛𝑔𝑢𝑙𝑎𝑟

𝑤𝑒𝑙𝑑

𝐷𝑖𝑟𝑒𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑡ℎ𝑒 𝑓𝑜𝑟𝑐𝑒

22

5.3 Conclusions The rod lock is designed to secure the reaction tubes of the TSB till a maximum force of 9.1 mT. Only

standard parts (bolts and nuts) are used to assemble the rod lock which makes it easy to use and cheap

to produce.

The total weight of the rod lock is higher than 23 kg, but that was needed due to the stresses. The mean

reason for this requirement was that it should be possible for one person to connect the rod lock

because 1 person it allowed to lift 23 kg maximum (7). However, the rod lock is installed in pieces and

every part which is installed at once is lower than the maximum weight. The approximate weight of the

components to be installed are:

- Split collar: 20.0 kg (total) - Rod: 1.5 kg each - Front Plate: 12.1 kg - Nut+Washer: 1.0 kg (total)

The total weight of 1 rod lock is 45 kg. The heaviest part that needs to be handled offshore is the front

plate, 12.1 kg.

For the removing procedure, the ROV is used to cut both rods of the rod lock to release the TSB’s which

is an easy and quick method. To use the ROV in this way is discussed with the ROV specialist and he

agreed. A technical drawing of the rod lock can be found in Appendix E and a summary of the unity

checks for all parts is presented in Table 5, where all values are within acceptable limits.


Rods 0.72 5.2.1 Thread on Rods 0.85 5.2.1 Front Plate 1.00 5.2.2 Split Collar 0.27 5.2.3 Shell Halve 0.88 5.2.4 Weld Shell Halve 0.76 5.2.4 Connection M24 Bolts 0.88 5.2.4 Table 5: Unity checks for the rod lock mechanism

5.4 Recommendations When the rods of the rod lock are connected to the split collar it should be taken into account that the

rods or split collar can bend due to gravity before the front plate is installed. After installing the front

plate, the rod of the clamping system fits into the hole which is milled out the front plate and will

support the rod lock and prevent it against bending.

To use the wire cutter, the ROV needs a clearance of 80 mm to the environment. This is realized for the

rod lock itself, but this should also be checked for the rest of the environment (the TSB). It can be

difficult for the ROV to reach the rods with the wire cutter because they are located underneath the TSB

and the clearance between the rod lock and TSB can be small. The ROV is also used in a previous project

to release the old rod locks which where unlock at a similar location, but it should be tested.

23

6 Bullnose Guide

When the tendons with the TSB’s are installed, the TLP will be transported from the yard to the correct

location on sea. After that the TLP is positioned above the tendons and all 8 tendons will be connected

to the TLP by using the tendon porches on the TLP. To guide the tendons into the tendon porches a CT-

winch (winch with a constant tensile force of 10 mT) located on top of the TLP is used. A wire with a

ballgrab (Figure 13) is attached to this winch, see Figure 14.

Figure 13: Ballgrab used to guide the tendons into the tendon porches of the TLP

This ballgrab is a rod with balls on its surface located on the inside of the rod and can move outwards.

When this ballgrab is inserted into the bullnose (marked red in Figure 14) of the top tendon section the

balls move outwards to lock the ballgrab and a pulling force is applied on the ballgrab by the CT-winch

so all the tendons can be pulled inside the tendon porches at the same time.

Figure 14: Ballgrab connection to the tendon top section

As can be seen in Figure 14, the bullnose (red part) has a flat surface on top next to the ballgrab and the

problem in a previous project with a similar scope was that this part got stuck underneath an edge of

the TLP (see Figure 15) and inside the tendon porch with the result that the ballgrab was pulled out of

the bullnose. Details of these snag points can be found in Appendix F. This chapter describes a guide

which prevents the tendon for being stuck at the snag points during the connection procedure.

24

6.1 Problem Definition At this moment, Heerema is installing another TLP located in the Gulf of Mexico called Bigfoot. This is

also a TLP with the major difference that this one is bigger than Malikai and therefore there are 16

tendons used to install the TLP instead of 8 tendons for Malikai. To connect the tendons to the TLP,

there are also tendon porches used and the project team came up with the following lessons learned

related to the insertion of the tendons into the tendon porches.

No Observation Recommendation

1 Premature release of ballgrabs while under tension (8 out of 16)

Suspect marine growth inside the tendon receptacles; investigate cleaning by ROV. Other reason can be tendon movement due to high current (wiggling). HMC will contact ballgrab manufacturer and consult. Check if adding hinge in between socket and ballgrab improve ballgrab connection.

2 Existing design of porches and TTCA bell guide allows CT-wire sockets to get trapped; no guidance of top of tendon once tendon has entered porch

Check if shroud placed over socket, ballgrab and top of tendon will improve guidance. Check if installing ballgrabs at draft of 61ft aids in lining up the tendons with the porches.

3 Ballgrab on T11 disconnected for top of tendon. This caused CT-winch to haul in wire, which was stopped by centralizer frame.

To ease visual confirmation that wire and ballgrab is still connected to the top of tendon investigate to add paint markings on the winch wire.

4 CT-winches operated at 5 mT as per OIM.

Increase constant tension to 10 mT by adjusting CT-winch settings. Investigate if increasing tension load beyond 10 mT by adding sheave into arrangement and connecting winch wire back to CT-platform is feasible.

5 CT-winch wires got damaged due to large movement of tendons and sharp edge underneath tendon porch.

Inspect and cut off damaged part of wire and re-install new sockets.

6 In case of currents and misalignment of tendons, 2 ROV's is insufficient to keep proper overview.

Preference for 4 ROV's (plus one spare) to allow simultaneous inspection of all corners.

The scope of this chapter is related to observation no. 1, 2 , 3 and 4 because this problems can be solved

by adding an extra guide which will be described hereafter. The other observations will be discussed in

the recommendations, because this has something to do with the design of the TLP and bullnose which

are already in production for Malikai or are already finished so it cannot be modified anymore. These

recommendations are provided to the related companies which produce these equipment.

The 2 major snag points are given in Appendix F. Snag point 1 is the same as the one marked in Figure 15

which is the edge on the downside of the TLP and snag point 2 is the one inside the tendon porch. To

prevent the flat top surface of the bullnose for being stuck somewhere at these snag points, an extra

guide is needed for the bullnose and ballgrab.

25

Figure 15: Marked snag point of the bullnose under TLP

6.2 Bullnose Guide Design The bullnose is already in production so to change the geometry of this one is not an option. Another

solution is to add a guide around the ballgrab which has a rigid connection with the bullnose.

The resulting bullnose guide is a solid cone connected between the flanges of the ballgrab which are

normally used to release and insert the ballgrab. This guide will be installed on deck and the design can

be seen in Figure 16 with the technical drawing in Appendix G.

Figure 16: Bullnose guide around the ballgrab connected with bolts and the configuration during the insertion and the

disengaging

𝑑𝑖𝑠𝑒𝑛𝑔𝑎𝑔𝑖𝑛𝑔

𝑖𝑛𝑠𝑒𝑟𝑡𝑖𝑜𝑛

26

The guide has the geometry of a solid cone with a total height of 100 mm, a maximum outer diameter of

200 mm at the bottom side and a minimum outer diameter of 146 mm at the top side as can be seen in

the technical drawings in Appendix G. The inner diameter of the guide has a clearance of 2 mm with the

outer diameter of the ballgrab flanges so the guide will be supported by 8 M10 bolts between the two

flanges of the ballgrab.

The 8 M10 bolts have a clearance with the ballgrab which is higher that the clearance between the guide

and flanges so that if a side force is acting on the guide, the guide is supported by the flanges of the

ballgrab and not the bolts, see Figure 16. This is not updated in technical drawings of Appendix G yet,

but will be done by the drafter. For the vertical forces, the guide will rest on the bullnose of the top

tendon because of the clearance between the bolts on the down side of the guide and the lower flange

of the ballgrab.

Normally the ROV inserts and disengages the ballgrab by grabing it between the flanges using the 6”

parallel gripper with the Atlas arm (8). With the new design the ballgrab is covered by the guide so this is

not possible anymore. For Malikai there are holes milled out the guide, as can be seen in Appendix G, so

the ROV can lift up the whole guide which is explained hereafter.

Insertion Ballgrab

During the insertion phase of the ballgrab, it is lowered down by the CT-winch through the tendon porch

after which it is pressed inside the bullnose of the tendon top section by the ROV. The bullnose guide is

already connected to the ballgrab on deck so the ROV grabs the ballgrab around the pin which connects

the bullnose to the wire (above the bullnose guide). The guide is supported around the ballgrab by bolts

when it slides down due to gravity, see Figure 16, and shifts to the correct position when the ballgrab is

pressed inside.

Disengage Ballgrab

Also the disengagement is done by the ROV. The ROV grabs the guide by putting the gripper into the

holes of the guide and lifts up the guide. The 4 bolts on the topside of the guide lifts up the ballgrab, see

Figure 16, at the same time to unlock it.

6.3 Calculations

6.3.1 Bearing Stresses

The CT-winch has a constant tensile force of 10 mT which is also used as the vertical incoming force on

the guide. The horizontal side force is 10% of the vertical force as is specified by the Heerema standard

criteria SC-251 (1). This impact forces are given in Figure 17 with the following forces:

𝑃𝑣 = 98.1 𝑘𝑁

𝑃ℎ = 9.81 𝑘𝑁

The impact forces result in a bearing stress in the bullnose guide.

27

Figure 17: Horizontal and vertical impact forces on the bullnose guide

Vertical Force 𝑷𝒗

When the vertical impact force is acting on the outside of the guide, the guide is supported on the

downside by the top of the bullnose. For the bearing calculation, the force is acting on one point with a

load spread of 1:2.5 which gives a surface A with a semicircle shape on the downside of the guide.

Figure 18: Load spread area A on the downside of the bullnose guide

100

25 𝐴

𝑂𝑢𝑡𝑒𝑟 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑑𝑜𝑤𝑛𝑠𝑖𝑑𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑔𝑢𝑖𝑑𝑒

62.5

𝐼𝑛𝑛𝑒𝑟 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑑𝑜𝑤𝑛𝑖𝑑𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑔𝑢𝑖𝑑𝑒

28

The surface A becomes:

𝐴 = 785.4 𝑚𝑚2

Which gives for the bearing stress:

𝜎 =𝑃𝑣

𝐴= 124.9 𝑁

𝑚𝑚2⁄ → 𝑈. 𝐶. =124.9

0.9 ∗ 345= 0.40

Horizontal Force 𝑷𝒉

When the horizontal impact force is acting on the outside of the guide, the guide is supported on the

inside by the flanges of the ballgrab. The surface A, located on the inside of the guide, is calculated in a

similar way as was done in Figure 18 but now the area has a rectangular shape where the width is still

related to the load spread and the height to the thickness t of the flat surface of the flange: 4 mm, this

gives for the area A:

𝐴 = 200 𝑚𝑚2

And for the stress:

𝜎 =𝑃𝑣

𝐴= 49.1 𝑁

𝑚𝑚2⁄ → 𝑈. 𝐶. =49.1

0.9 ∗ 345= 0.16

6.3.2 Maximum Pull Force ROV

During the release phase of the ballgrab out of the bullnose, the ROV grabs the guide and lifts it up

including the ballgrab. The guide pulls the ballgrab out of the bullnose by the use of the 4 upper M10

bolts (see Figure 16) which results in a shear stress on these bolts.

A325 M10 bolts:

- Actual shear area = 58 𝑚𝑚2

- Allowable shear stress = 17.0 𝑘𝑠𝑖 = 117.2 𝑁/𝑚𝑚2 (AISC, table J3.2 (3))

In total there are 4 bolts which gives a maximum pull force by the ROV of:

𝐹 = 4 ∗ 58 ∗ 117.2 = 27.1 𝑘𝑁 = 2.5 𝑚𝑇

The maximum lift of the ROV arm is 500 kg (8) and results in a U.C. of:

𝑈. 𝐶. →500

2500= 0.20

6.4 Conclusions Regarding the problem definition, the problems given in observation 1 till 4 are solved when the guide

cone is placed around the ballgrab due to the guidance of the cone. The other observations cannot be

solved by using the guide and has something to do with the design of the TLP. These observations are

discussed in the recommendations.

The maximum pull force of the ROV before the bolts will fail is 27.1 kN which is strong enough since the

arm of the ROV can lift a maximum of 500 kg (8). The pulling needed to release the ballgrab is unknown

and should be checked with the ballgrab manufacturer, but from earlier experience by Heerema is

29

concluded that this can also be done by hand. This should be way lower than 500 kg so the allowed

maximum force by the arm should not give any problems.

All used items within the calculations are suitable for this offshore installation purpose. A technical

drawing of the bullnose guide can be found in Appendix G and all values are within acceptable limits as

can be seen in Table 6.


Bearing stress due to vertical impact load 0.40 6.3.1 Bearing stress due to horizontal impact load 0.16 6.3.1 Maximum pull force on the ballgrab 0.20 6.3.2 Table 6: Unity Checks for the bullnose guide

6.5 Recommendations Regarding the bullnose guide:

It should be checked with the ballgrab manufacturer what the force will be to release the ballgrab to

make sure that the 4 M10 bolts used at the top section of the guide and the ROV arm are strong enough

to lift the ballgrab including the guide cone.

For the impact force in the calculations it is assumed that they are equal to the pulling force of the CT-

winch, but it is also possible that the movement of the TLP and the tendons result in an impact force on

the guide. It would be useful to look at these forces to be sure that it will not damage the guide and

maybe got stuck somewhere in the tendon porch.

Regarding the other observations:

The guide cone only helps the tendon to go into the tendon porch more smoothly than before. When

the tendon is still underneath the TLP, the CT wire can be damaged by the sharp edge on the downside

of the TLP due to the movement of the tendons. When this happens, the damaged part of the wire

should be cut off and a new socket must be installed. To prevent this damage, the design of the

downside of the TLP should be reconsidered close to the tendon porches. The sharp edges must be

removed and changed to a more smooth and guided surface.

Same as for Bigfoot, there are four corners of the TLP where the tendons are connected to. For Bigfoot

there are four tendons at each corner and for Malikai two. Only two ROV’s where used to guide all the

tendons into the tendon porches. For a simultaneous inspection it would be better to use four ROV’s

(one for each corner) to have a visibility at each corner during the whole insertion phase. This would be

useful to do for Malikai, but the vessel which is used for the installation is too small to carry four ROV’s

so also for this project two ROV’s is the maximum. Another visual inspection, like fixed cameras, can be

considered.

30

7 H-Link Support Frame One part of the Malikai TLP installation is to pre-lay the 8 mooring lines on the seabed by the use of

suction piles to fasten it. The mooring lines are build up with a chain on both ends and a polyester rope

in the middle. To connect the chain and polyester rope, an H-link is used which will be connected on

deck to the polyester rope and chain as can be seen in Figure 19.

Figure 19: Connection of the polyester rope (left side) and the chain (right side) to the H-link. Be aware that this is the H-link

used in previous project and the one for Malikai is different.

The weight of the H-link is about 900 kg and the geometry for the Malikai H-link can be found in Figure

20 with the transportation shackle attached to it. During the mooring line installation these H-links are

needed on two locations on deck of the Aegir. First location is between the Mooring Line Deployment

(MLD) and the Spooler Winch (SW) and the other one next to the stern Chain Hang Off Point (CHOP)

where the H-link will be connected to the polyester rope ends and the chains. To make this connection

procedure easier, a support frame is needed for this H-link, an H-link support frame. There are two

frames needed, one on each connecting location. The technical drawings of the H-link frame can be

found in Appendix H.

Requirements

The H-link support frame should suit the following requirements:

- Support the H-link at an height such that it is easy for a person to connect the pin in the H-link

- Solid design and support for offshore purposes

- Not too heavy and easy for transportation

- Support the chain and thimble of the polyester rope so that the pin can be connected easily

31

7.1 H-Link Support Frame Design The H-link support frame will be used to hold the H-link about 300 mm above the ground so the thimble

with the polyester rope and the chain can be connected with a pin.

The H-link support frame is based on 2 C-channel beams connected to each other with 2 T-profiles build

up by 2 plates each. On top of the C-channel, 8 guides are located such that the support points of the H-

link are in line with the guides. This results in an overall length of 1354 mm, overall width of 657 mm and

a weight of approximately 170 kg for the frame.

Figure 20: H-link support frame including the H-link resting on top of it and can be transported with the shackle attached on the top side

The top plates of the T-profiles between the C-channels will support the thimble and the chain for being

in the right position to connect both with a bolt to the H-link. The position of the bolts can vary so the

right height of the thimble and chain can be reached by adding an extra steel plate on top of the T-

profile offshore.

7.2 Transportation There are two ways to transport the H-link support frame:

- Fork lift pockets

- Lifting with a crane

It has fork lift pockets on the downside so it can be picked up by a forklift truck but also four holes in the

side-flanges where a shackle can be attached for a four point lift system. The frame will not be fixed to

the deck because this reduces the working time and the incoming force is only from the topside.

The size of the forklift pockets are inline with the forklift truck available on the Aegir as this is discussed

with the field engineer of the Aegir. For the lift system, a rigging design needs to be done to know the

stresses in the slings, shackles and crane. The details of the rigging design according to the Heerema

standard criteria (SC-201, SC-291, SC-292) (1) can be found in Appendix I with the following results:

32

Figure 21: Four point lift system where the C.o.G. is indicated

- 𝑊𝑑𝑒𝑠 = 187 𝑘𝑔

- Rigging angle 𝛼 = 67.5°

- 𝐹𝑣𝑟𝑖𝑔= 𝐹𝑟𝑖𝑔 = 90 𝑘𝑔

- 𝐹𝑣𝑙𝑝= 𝐹𝑙𝑝 = 84 𝑘𝑔

- Load limit shackles: 3.33 𝑚𝑇

Green Pin Standard Shackles of 4.75 mT delivered by “Van Beest BV” (9) are used to attach the slings to

the frame. Because of the low weight of the frame, the rigging is overdesigned but inline with the rigging

available on the Aegir. Also the stresses in the padeyes of the side flanges of the frame are investigated

with one of the Heerema excel sheets as can be seen in Appendix J. This gives the stress for different

cross-sections of the padeye based on the Heerema standard criteria SC-292 (1).

7.3 Calculations Also for this frame, the stresses in all the parts and welds will be checked. The results are given in Table

7 including the impact forces and load cases for the resulting stresses. All these stresses are very low

and will not become critical. This is also the reason that the detailed calculations are not shown in this

report, only in the design report which is provided to the client.

All the calculations are based on the most worst cases scenarios and highest impact forces.

Part of the frame Impact force Stress [𝑵𝒎𝒎𝟐⁄ ]

C-Channel 60% of the weight of the H-link on top of one c-channel as a simply supported beam.

5.61

Guides Horizontal impact force which is 10% of the total vertical impact force (weight) of the H-link, according to the

11.00

𝑥 𝑙

𝑦 𝑏

𝐻𝑑𝑒𝑠

𝐹𝑣𝑙𝑝

𝐹𝑣𝑟𝑖𝑔

𝛼

𝑊𝑑𝑒𝑠

𝐶. 𝑜. 𝐺.

𝑙 = 875 𝑚𝑚

𝑏 = 579 𝑚𝑚

𝑥 = 381 𝑚𝑚

𝑦 = 290 𝑚𝑚

33

standard Heerema criteria SC-251 (1).

Welding All welds are check but the weld of the horizontal plate of the T-profile due to an impact force of the chain and thimble on this plate gives the most critical stress.

14.78

Padeyes The padeye capacity is checked with one of the Heerema excel sheets, see Appendix J.

168.6

Table 7: Resulting stresses in all components of the H-link Support Frame

7.4 Conclusions Regarding the requirements, the H-link support frame contains only standard materials and parts which

are deliverable at the production location in Asia which reduces the price and difficulties in the

production. The H-link is held about 300 𝑚𝑚 above the ground by the frame and gives the opportunity

to the field engineers to connect the pin easily because the chain and thimble are also support at the

correct height. For a crane or fork lift truck it is very easy to transport the H-link frame to correct

position by using the forklift pockets or connecting a lift system to the holes/padeyes in the side flanges

by using 4.75 mT shackles.

All used items within the calculations are suitable for this offshore purpose. A technical drawing of the

H-link frame can be found in Appendix H and all values are within acceptable limits as can be seen in

Table 8.


C-Channel 0.03 Table 7 Guides 0.05 Table 7 Welding 0.10 Table 7 Rigging 0.03 Appendix I Padeyes 0.21 Appendix J Table 8: Unity Checks for the H-link support frame

7.5 Recommendations For now, the frame will not be fixed to the deck and stands loose which should be fine for this sort of

frames on the Aegir. In case that the frame becomes out of balance with the H-link on top of it due to

weather or motions of the sea, the field engineers can decide to fasten the frame to the deck by welding

a flat steel plate under an angle of 45° to the frame and deck.

It would be useful to have a kind of support for the pin when this one is connected by a person to the H-

link due to the weight of the pin. It is not integrated in the frame yet because of the deviation in the

dimensions of each H-link which leads to a different position of the hole where the pin needs to be

inserted each time an H-link is placed on top of the frame. A separate support or an adjustable support

inside the frame would be useful.

34

8 ILT Modifications The tendons are transported horizontal with a barge to the location where the TLP will be installed. To

install them, the first step is to upend them from the barge which is done by the crane of the Aegir. The

rigging arrangement that is used contains an internal lift tool (ILT). This ILT has a cylindrical shape which

contains on one side a lifting hook with a shackle and the other side is slide into the tendon. To fit the

ILT perfectly into the tendon, the gripping segments expand outwards against the inside of the tendon.

These segments are hydraulic actuated due to the lift force after which the crane can lift up the tendon

and rotate it to the vertical position. The ILT in combination with the tendon, before it is pulled in, is

shown in Figure 22. All equipment attached to the ILT can be found in Figure 24.

Figure 22: ILT before it is pulled into the tendon with the use of a support frame

For the pull in procedure, an ILT support frame is set on the barge in front of the tendons which are

laying horizontal and next to each other. The horizontal lifting arm is used to guide the ILT in the right

position on the support frame for the pull in. When the support frame is in the correct position, the ILT

is slide over the frame and pulled inside the tendon by cables. It is also possible to use the horizontal

lifting hook as is done in Figure 22. The disadvantage is that the crane, which lifts the ILT, stands on the

vessel and has different motions than the barge where the tendons are laying on. This makes it difficult

to align the ILT in front of the tendon and so not used for Malikai.

Upend Method

Because the vessel (Aegir) has only one crane, it is used in the Split Block method to upend the tendons

from the barge. Two blocks with a hook are lowered down from one crane and are fixed to each side of

the tendon. One of them will be connected to the ILT. When the tendon is lifted to the vertical position,

the ILT is in the topside of the tendon. The segments of the ILT will automatically be actuated when

there is a lift force applied in the direction marked green in Figure 23.

35

Figure 23: Link plate with a connected chain for holding it at the rest position, ILT from Ichthys project

Because of the Split Block method, the lift force will be in the direction of the red area in Figure 23.

Therefore a link plate is needed which ensures that the support plate (see Figure 24) acts as a rotation

point so that the force on the ILT is always in the direction which actuates the segments even when the

lift force is in the red direction in Figure 23.

8.1 Assignment The pull in procedure with the ILT support frame and ILT is also done in previous projects with a similar

scope, Moho and Ichthys. Therefore the different parts which were used that time will be combined in

the correct way. This is the most easy and quickest way to get a suitable pull in procedure for the

Malikai project.

This chapter describes a recommendation for Heerema and the other involved company IHC Merwede

to use all the equipment from two previous projects in a correct way.

8.2 Heerema’s Scope of Work First of all, Heerema has to make choices for the equipment they have to produce by their own.

Malikai project team will design an ILT support frame (green item in Figure 24) and has to choose the

type of ILT they want to use. The support frame will be the one from Moho project because of the easy

and suitable design, but there are some modifications needed based on the lessons learned as discussed

in the recommendations. For the ILT holds that there are two options:

- ILT-16/17, which are owned ILT’s by Heerema (same as Moho project)

- Rent ILT from IHC (same as Ichthys project)

𝐿𝑖𝑛𝑘 𝑃𝑙𝑎𝑡𝑒

𝐶ℎ𝑎𝑖𝑛

36

With IHC these scenarios must be discussed because Heerema is not sure which one they want to use.

ILT-16/17 will be the base case because this one is owned and is much cheaper than a rental one.

Figure 24: ILT pull in procedure with all the equipment needed

8.3 IHC’s Scope of Work The yellow items in Figure 24, needed for the pull in procedure, were also used in the two previous

projects built by IHC who will also arrange these equipment for Malikai. They have to be flexible on both

ILT scenario’s because it is still not known which one will be used. The items are discussed hereafter and

also is mentioned which configuration is used in the Moho and Ichthys projects.

Horizontal lifting arm

The lifting arm on top of the ILT is used to transport the ILT with a crane and put it in the correct

position in front of the tendons for the pull in procedure. This arm should be designed such that it can

work in combination with a link plate.

- Moho: The horizontal lifting arm is not ready to use in combination with a link plate. The end of

the tendon piles must support the link plate but the lifting arm is located between the support

plate of and the tendon pile so a modification of the horizontal lifting arm is needed.

- Ichthys: For Ichthys, also a link plate is used so the lifting arm is suitable to work with it. This

lifting arm has a hole inside it at the location where the support plate must be in contact with

the tendon pile.

𝑇𝑒𝑛𝑑𝑜𝑛 𝐼𝐿𝑇

𝐼𝐿𝑇 𝑆𝑢𝑝𝑝𝑜𝑟𝑡 𝐹𝑟𝑎𝑚𝑒

𝐻𝑜𝑟𝑖𝑧𝑜𝑛𝑡𝑎𝑙 𝐿𝑖𝑓𝑡𝑖𝑛𝑔 𝐴𝑟𝑚

𝐿𝑖𝑛𝑘 𝑃𝑙𝑎𝑡𝑒

𝑆𝑢𝑝𝑝𝑜𝑟𝑡

𝑃𝑙𝑎𝑡𝑒

𝑆𝑙𝑒𝑑𝑔𝑒

𝑃𝑢𝑙𝑙 𝐼𝑛 𝑐𝑎𝑏𝑙𝑒

𝐴𝑐𝑐𝑢𝑚𝑢𝑙𝑎𝑡𝑜𝑟

𝑇𝑟𝑎𝑛𝑠𝑝𝑜𝑛𝑑𝑒𝑟𝑠

(𝑖𝑛𝑠𝑖𝑑𝑒)

37

Sledge

The sledge must be designed such that it suits the ILT support frame where it slides over. This frame has

the Moho sledge foot print.

- Moho: The ILT support frame from Moho is used for Malikai so the sliding frame will fit.

- Ichthys: Another ILT support frame is used in this project so should be modified that it will fit the

new support frame.

Accumulator

Due to the waterdepth of Malikai an accumulator is needed.

- Moho: Located inside ILT

- Ichthys: Not included in the ILT, should be hired and added to the ILT

Link Plate and Chain

The ILT needs to be equipped with a link plate as is explained in section 0 and should be checked to work

with the tendon piles used for the Malikai project. The diameter of the tendon should correspond with

the location of the support plate. A chain is needed to hold the link plate in the vertical position when it

is in rest.

- Moho: There was no link plate or chain used for Moho project, this should be added to the ILT.

- Ichthys: ILT already contains a link plate and chain, only the diameter of the tendon pile should

be checked with the link plate.

Transponders

The transponders are used to locate the ILT and tendon underwater when these are lowered down. For

Malikai these must be integrated into the sledge for covering.

- Moho: The transponders were already located in the sledge.

- Ichthys: The transponders were located into the arms of the ILT and should be integrated into

the sledge.

8.4 Conclusions With IHC two scenarios must be discussed as there are still two ILT scenarios in this stage of the project:

- ILT-16/17, which are owned ILT’s by Heerema (same as Moho project)

- Rent ILT from IHC (same as Ichthys project)

Using the owned ILT-16/17 will be base case because of costs.

38

In the following table are the actions for the two ILT scenarios summed for Heerema and IHC. It gives an

overview which part should be taken from which previous project for each ILT option. When it says OK,

the suitable parts for Malikai project are already incorporated in the ILT. All parts can be found in Figure

24.

Heerema’s scope:

ILT-16/17 (Heerema own) Rent ILT from IHC

ILT Support Frame Moho project: ILT support frame for 84’’ O.D. anchor mooring pile.

Moho project: ILT support frame for 84’’ O.D. anchor mooring pile.

IHC’s scope:

ILT-16/17 (Heerema own) Rent ILT from IHC

Sledge OK Remove the sledge from the ILT and replace it by the one from the ILT-16/17 (Moho project).

Horizontal Lifting Arm The arm should be modified such that it is not in between the support plate and the tendon as is done for the Ichthys project.

OK

Link Plate A link plate must be added to the ILT so it can work in combination with the split block lifting procedure. The same link plate is needed as in the Ichthys project. The diameter of the tendon piles (for supporting link plate) must be checked with the support plate of the link plate.

The diameter of the tendon piles (for supporting link plate) must be checked with the support plate of the link plate.

Chain A chain for supporting the link plate in rest must be attached to the plate and ILT, same as Ichthys project.

OK

Transponders OK Transponders are located into the arms of the ILT. For Malikai, these transponders need to be integrated into the sledge like on Moho project.

Accumulator OK Because of the waterdepth, an accumulator is needed and must be added to the front of the ILT like in the Moho project.

8.5 Recommendations When an accumulator is attached to the front of the ILT, the sledge is probably too light because the

C.o.G. can be in front of the sledge. To get a much more static design, either reinforce the sledge or

build a new one. For both cases the Moho foot print needs to be obtained to work with the support

frame.

39

From previous pull in procedures in the Moho project is learned that the ILT support frame is not strong

enough to guide the ILT when it is located at the end of the frame as is shown in Figure 25. Due to the

weight, the support beams were rotating so either make the support point of the beams closer to the

tendon or use additional welds to lock the beams better in the support frame.

Figure 25: Rotation of the support beams on the support frame due to the weight of the ILT at the front

40

9 Conclusions

The internship assignment contains five problems for the TLP installation which needs to be solved. This

is done by designing new equipment or a modification of the layout used in the past. A summary of the

problem definitions, final design and the results are written in this report. The specific conclusions for

each design are already provided at the end of each chapter.

During the designing period, the final concept for the rod lock mechanism and bullnose guide were

shown to the client with a presentation and discussion during the weekly meeting. With their approval,

the final designs were made as is also done for the other problems. All designs were also presented and

discussed with the Heerema field specialists so everything will work and fit during the installation. The

corresponding technical drawings are made, reviewed and added to the design reports.

To show that every part, weld and installation equipment cannot fail, the unity check is introduced.

After each calculation, the value for the check is given as can be seen in the detailed conclusions in the

design chapters. All used items within the calculations are suitable for offshore transportation and

installation purposes and the values are within acceptable limits. Detailed calculations are only written

in the original Heerema design reports used within the Malikai project. These reports are all approved

by Heerema engineers and ready to send to the client for their comments.

41

10 Recommendations

All specific recommendations corresponding to each design are provided in the design chapters in this

report. Here, the next steps in the design process are discussed where the other engineers can work on.

At this point in time, the design reports and technical drawings are finished, reviewed by other Heerema

engineers and signed off. The next step is to send the reports, including the drawings, to the client so

they can gives their comments. They return the comments with a corresponding code:

- Code 1: Accepted

- Code 2: Accepted with comments

- Code 3: Not accepted, revise and resubmit

Within the internship period, the guide cone seafastening report is already code 2, updated with their

comments and send back to the client. All other parts are ready to send for the first client review. Other

structural engineers of the Malikai project have to survey these review cycles and update the reports

where the drafter has to update the drawings.

The installation engineers have to provide the installation manuals which describes the working

principles and the points of attention for the field engineers during the TLP installation. Besides that, the

quality control (QC) engineer has to make checklists for all the equipment used and installation

procedures. This is done to watch over the quality and safety and make sure that the field engineer

checks everything before is it used.

42

11 Bibliography

1. Standard Criteria. Heerema Marine Contractors.

2. Johari, Noor Farina. Specification for Materials. Heerema Marine Contractors. 2013. MLK-012-900-

AA-7730-0001.

3. AISC. Manual Steel Construction. 8/9th edition.

4. API. Recommended practice for planning, designing and construction fixed offshore platforms. 20th

edition.

5. PJC. Miclyn Barge M3316, M3317, M3318, M3319 & M3320 Capacities. Heerema Marine

Contractors Australia Pty. Ltd. 2013.

6. General Guidelines For Marine Transportations. Noble Denton. 2005. 0030/NDI Rev. 2.

7. Arboportaal. [Online] http://www.arboportaal.nl/onderwerpen/tillen-en-dragen.

8. Schilling Robotics ATLAS 7R Manipulator. FMC Technologies. 2013.

9. VanBeest Catalogue Complete. Van Beest BV, manufacturer and supplier of wire rope and chain

fittings. Reg. trade mark ‘Green Pin’. p. 15.

10. Barclay, C. Design of heavy lift rigging for use with the DCV 'Aegir'. Heerema Marine Contractors.

2014. EG-009, Rev. 1.

43

Appendix A – Stresses in Weld

1

𝜏∥ =𝐹𝑦

2 ∗ 𝑎 ∗ 𝐿

2

𝐹𝑠 = 𝐹𝑦 =𝐹𝑥2

√2= 0.353 ∗ 𝐹𝑥

𝜏⊥ = 𝜎⊥ =0.353 ∗ 𝐹𝑥

𝑎 ∗ 𝐿

3

𝐹𝑠 = 𝐹𝑦 =

𝐹𝑦

2

√2= 0.353 ∗ 𝐹𝑦

𝜏⊥ = 𝜎⊥ =0.353 ∗ 𝐹𝑦

𝑎 ∗ 𝐿

4

𝜏⊥ = 𝜎⊥ =

1

2√2∗ 6 ∗ 𝑀𝑦

𝑎 ∗ 𝐿2

5

𝐹𝑠 = 𝐹𝑦 =𝐹𝑧

√2

𝜏⊥ = 𝜎⊥ =

1

√2∗ 𝐹𝑧

𝑎 ∗ 𝐿

6

𝐹𝑦 =𝑀𝑧

𝑆 +12 𝑎√2

𝜏∥ =𝐹𝑦

𝑎 ∗ 𝐿

A

GRAPHIC SCALE 0

1 : 2

40 80 240 mm120 160 200

6. FOR GENERAL NOTES SEE DWG. HI-133-55-01.

7. ALL SEAFASTENING PLATES TO BE LINED UP WITH BARGE FRAMES.

1 : 2

DETAIL

-

1 EACH GUIDE CONE

0184331HI1 : 25

GENERAL NOTES

REFERENCE DRAWINGS

GRAPHIC SCALE 0

1 : 25

1000 1500 2500500 2000 3000 mm

SECTIONS AND DETAILS

B

I0417.00000

SABAH SHELL MALIKAI TLP

AF 01R - FOR REVIEW

HI-133-55-01

AT @ 90° INTERVALS

PL. 16

FR. 4, 7, 10, 13, 37, 40, 43, 46

SHELL DOC. NO. REV NO.

02A

C

FRAME

1 : 25

8x REQ'D

ELEVATION

PLAN

1

-

SEE NOTE 8

MLK-012-900-CS-4018-0260-001

MLK-012-900-CS-4018-0260-001

GUIDE CONE SEAFASTENING

OF BARGE

15-MAR-2015

290

152

178

ON BARGE LAYOUT

TENDON SUPPORT BUOY, GUIDE CONES AND HAMMERS

6

4 x REQ'D

NO WELD AT GUIDE CONE

BY FABRICATOR).

8. INDICATES OFFSHORE CUT-OFF LINE (TO BE PAINTED YELLOW

6‘Ø äB AA28-MAY-2015 02A - REV. AS IND./FOR CONSTRUCTION

5. ALL WELDS TO BE FULLY PENETRATED UNLESS NOTED OTHERWISE.

4. ALL WELDS TO BE IN ACCORDANCE WITH A.W.S. STANDARDS.

3. INSPECTION TO HMC SPECIFICATION 001, SECTION 6, CATEGORY B.

2. MATERIALS TO HMC SPECIFICATION 001, SECTION 2, TYPE V.

STRUCTURAL STEEL'.

1. FABRICATION TO HMC SPECIFICATION 001, 'WELDING AND FABRICATION OF

9. ESTIMATED DESIGN WEIGHT OF GUIDE CONE IS APPROX. 11.5 m.T.

B

B

B

25

R

C.O.G

1755

B

FOR CONSTRUCTION1

B

6 Ø äå

REV. DATE DRAWN

PROJECT

SUBJECT

DESCRIPTIONAPPROVED APP'D

JOB NO. DRAWING NO.

DISCIPLINE SUBJECT NO. SHEET NO. REVISION

OPS.

PR

EP

AR

ED U

SIN

G H

EE

RE

MA'S C

AD/

CA

E S

YS

TE

M

ENGINEERING

- - -

MARINECONTRACTORS

CLIENT'S DRAWING NO.

SCALE ( A1 FORMAT )

IDENT. NO.

01-Jun-2015

18:2

4:3

5...\I0

417\I0

417.0

0000\

HI-

133-84-01

: MicroStatio

n

HMC Offshore Services Malaysia Sdn. Bhd.

redistributed, retransmitted, published, or used to create derivative works.

in writing by HMC, remains the sole property of HMC, and may not be disclosed, copied,

confidential and proprietary information, which, unless otherwise expressly agreed to

Copyright HMC Offshore Services Malaysia Sdn. Bhd. (HMC).This document contains

SEE ABOVE

[email protected]

Getypte tekst

[email protected]

Tekstvak

Appendix B

5. m.T. = METRIC TONS.

4. LAY-OUT IS BASED ON POSH 330' X 100' BARGE.

HOUSE

WINCH

BOW

FR.0 FR.6 FR.13 FR.21 FR.29 FR.37 FR.45 FR.51

1281010980

100584

7620

7620

7620

7620

30480

14640 18234

0180331HI

1 : 200

GENERAL NOTES

REFERENCE DRAWINGS

GRAPHIC SCALE 0

1 : 200

4 8 12 16 20 24 m

DATE:

STILL IN PROGRESS

09-Feb-2015

ON BARGE LAYOUT

TENDON SUPPORT BUOYS AND HAMMERS

A

I0417.00000


TO HEEREMA APPROVAL.

FOR LOAD OUT AND TO RE-INSTALL

2. FABRICATOR TO REMOVE BARGE EQUIPMENT AS REQUIRED

ON SITE BY THE BALLAST ENGINEER.

MANDATORY, MINOR MODIFICATIONS CAN BE PERFORMED

3. THE BALLAST TANK FILLING PERCENTAGES ARE NOT

EXCL. RIGGING.

WEIGHT IS DRY WEIGHT PER TSB, INCL. 5% INACCURACIES,

(PRE-RIGGED SLINGS) INDICATED TRANSPORTATION

1. FOR CALCULATION INCLUDING RIGGING

6. GUIDES AND BUMPERS OMITTED FOR CLARITY.

A AF 01R - FOR REVIEW29-JAN-2015

HI-133-84-01 SEAFASTERNING GUIDE CONES SECTIONS AND DETAILS


01R

REV. DATE DRAWN

PROJECT

SUBJECT


JOB NO. DRAWING NO.


OPS.

PR

EP

AR

ED U

SIN

G H

EE

RE

MA'S C

AD/

CA

E S

YS

TE

M

ENGINEERING

- - -

MARINECONTRACTORS


SCALE ( A1 FORMAT )

IDENT. NO.

09-Feb-2015

11:3

7:1

6...\I0

417\I0

417.0

0000\

HI-

133-80-01

: MicroStatio

n






SEE ABOVE

erikr

Rectangle

erikr

Rectangle

erikr

Rectangle

[email protected]

Tekstvak

Appendix C

46

Appendix D – Transportation Forces of Guide Cone on Barge

Initial values for the calculations can be found in section 4.2.

Roll (to starboard)

In Figure 26 are the maximum static and dynamic forces given of the cargo for the case that the barge is

in the maximum roll amplitude.

Figure 26: Static and dynamic forces of the cargo when the barge it going to roll (1)

𝐹𝑣,𝑠𝑡𝑎𝑡𝑖𝑐 = 𝑊 ∗ cos(𝛼𝑟𝑜𝑙𝑙) = 113 ∗ cos(20) = 106.2 𝑘𝑁

𝐹ℎ,𝑠𝑡𝑎𝑡𝑖𝑐 = 𝑊 ∗ sin(𝛼𝑟𝑜𝑙𝑙) = 113 ∗ sin(20) = 38.6 𝑘𝑁

𝐹𝑣,𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 𝑀 ∗ �̈�𝑟𝑜𝑙𝑙 ∗ 𝑦 = 11.5 ∗ 0.1377 ∗ 0 = 0 𝑘𝑁

𝐹ℎ,𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 𝑀 ∗ �̈�𝑟𝑜𝑙𝑙 ∗ (𝑧𝑐𝑜𝑔 − 𝑧𝑐𝑜𝑟) = 11.5 ∗ 0.1377 ∗ (7.855 − 4.5) = 5.3 𝑘𝑁

𝐹𝑣,ℎ𝑒𝑎𝑣𝑒 = 𝑀 ∗ �̈�ℎ𝑒𝑎𝑣𝑒 ∗ cos(𝛼𝑟𝑜𝑙𝑙) = 11.5 ∗ 1.97 ∗ cos(20) = 21.3 𝑘𝑁

𝐹ℎ,ℎ𝑒𝑎𝑣𝑒 = 𝑀 ∗ �̈�ℎ𝑒𝑎𝑣𝑒 ∗ sin(𝛼𝑟𝑜𝑙𝑙) = 11.5 ∗ 1.97 ∗ sin(20) = 7.7 𝑘𝑁

𝑀𝑜𝑚𝑒𝑛𝑡𝑟𝑜𝑙𝑙 = 𝑀0𝐼𝑥 ∗ �̈�𝑟𝑜𝑙𝑙 = 34.36 ∗ 0.1377 = 4.7 𝑘𝑁𝑚

Pitch (to bow)

In Figure 27 are the maximum static and dynamic forces given of the cargo for the case that the barge is

in the maximum pitch amplitude.

z

y

𝑧𝐶𝑜𝐺

𝑧𝐶𝑜𝑅

z

y

𝜃

𝑊

𝐹ℎ,𝑠𝑡𝑎𝑡𝑖𝑐

𝐹𝑣,𝑠𝑡𝑎𝑡𝑖𝑐

Static

z

y

𝜃

𝐹ℎ,𝑑𝑦𝑛𝑎𝑚𝑖𝑐

𝐹𝑣,𝑑𝑦𝑛𝑎𝑚𝑖𝑐 𝐹𝑑𝑦𝑛𝑎𝑚𝑖𝑐

Dynamic

c

47

Figure 27: Static and dynamic forces of the cargo when the barge it going to pitch (1)

𝐹𝑣,𝑠𝑡𝑎𝑡𝑖𝑐 = 𝑊 ∗ cos(𝛼𝑝𝑖𝑡𝑐ℎ) = 113 ∗ cos(12.5) = 110.3 𝑘𝑁

𝐹ℎ,𝑠𝑡𝑎𝑡𝑖𝑐 = 𝑊 ∗ sin(𝛼𝑝𝑖𝑡𝑐ℎ) = 113 ∗ sin(12.5) = 24.5 𝑘𝑁

𝐹𝑣,𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 𝑀 ∗ �̈�𝑝𝑖𝑡𝑐ℎ ∗ (𝑥𝑐𝑜𝑟 − 𝑥𝑐𝑜𝑔) = 11.5 ∗ 0.0861 ∗ (7.32 − 50.292) = −42.5 𝑘𝑁

𝐹ℎ,𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 𝑀 ∗ �̈�𝑝𝑖𝑡𝑐ℎ ∗ (𝑧𝑐𝑜𝑔 − 𝑧𝑐𝑜𝑟) = 11.5 ∗ 0.0861 ∗ (7.855 − 4.5) = 3.3 𝑘𝑁

𝐹𝑣,ℎ𝑒𝑎𝑣𝑒 = 𝑀 ∗ �̈�ℎ𝑒𝑎𝑣𝑒 ∗ cos(𝛼𝑝𝑖𝑡𝑐ℎ) = 11.5 ∗ 1.97 ∗ cos(12.5) = 22.1 𝑘𝑁

𝐹ℎ,ℎ𝑒𝑎𝑣𝑒 = 𝑀 ∗ �̈�ℎ𝑒𝑎𝑣𝑒 ∗ sin(𝛼𝑝𝑖𝑡𝑐ℎ) = 11.5 ∗ 1.97 ∗ sin(12.5) = 4.9 𝑘𝑁

𝑀𝑜𝑚𝑒𝑛𝑡𝑝𝑖𝑡𝑐ℎ = 𝑀0𝐼𝑥 ∗ �̈�𝑝𝑖𝑡𝑐ℎ = 34.36 ∗ 0.0861 = 3.0 𝑘𝑁𝑚

z

x

𝑧𝐶𝑜𝐺

𝑥𝐶𝑜𝑅

𝑧𝐶𝑜𝑅 𝑥𝐶𝑜𝐺

z

x

𝐹ℎ,𝑠𝑡𝑎𝑡𝑖𝑐

𝑊 𝐹𝑣,𝑠𝑡𝑎𝑡𝑖𝑐

Static

𝜃

z

x

𝐹ℎ,𝑑𝑦𝑛𝑎𝑚𝑖𝑐

𝐹𝑑𝑦𝑛𝑎𝑚𝑖𝑐

𝐹𝑣,𝑑𝑦𝑛𝑎𝑚𝑖𝑐

𝜃

Dynamic

0123231SK

1 : 2

GENERAL NOTES

A

GRAPHIC SCALE 0

1 : 2

40 80 240 mm120 160 200

TSB ROD LOCK MECHANISM

A

I0417.00000


ISO VIEW

1 : 5

FOR INFORMATIONRKPMAY 2015

A-A

-

B-B

-

430 45

TYP.

615

= =

10

TY

P.

M20

AT 8 LOCATIONS

HEX NUT M20

TYP.

M20 WASHER

TYP.

M20 WASHER

AT 8 LOCATIONS

HEX NUT M20

==

90 30

TY

P.

127 O.D.

TSB ROD LOCK MECHANISM

45

GA

P

1

TY

P.

15

152

R

100

R

85

R

122

R

BO

TT

OM H

ALF

TO

P H

ALF

30

15R

L = 80

ROUND BAR DIA. 6

TYP.

25

TYP.

M24 WASHER

AT 2 LOCATIONS

HEX NUT M24

AT 2 LOCATIONS

HEX BOLT M24

65

R

304

66

244

55R

15R

SECTION B-B

-

L = 80

ROUND BAR DIA. 6

30

R

30

R

SECTION A-A

-

30

10TYP.

4TYP.

110

SEE NOTE 6

SEE NOTE 6

RODS NEED TO BE MARKED YELLOW FOR ROV WIRE CUTTER.6.

ALL WELDS TO BE FULLY PENETRATED UNLESS NOTED OTHERWISE.5.

ALL WELDS TO BE IN ACCORDANCE WITH A.W.S. STANDARDS.4.

or D.

INSPECTION TO HMC SPECIFICATION 001, SECTION 6, CATEGORY A, B, C 3.

MATERIALS TO HMC SPECIFICATION 001, SECTION 2, TYPE ..2.

OF STRUCTURAL STEEL'.

FABRICATION TO HMC SPECIFICATION 001, 'WELDING AND FABRICATION 1.

RE

F.

80

10TYP.

4TYP.

REV. DATE DRAWN

PROJECT

SUBJECT


JOB NO. DRAWING NO.


OPS.

PR

EP

AR

ED U

SIN

G H

EE

RE

MA'S C

AD/

CA

E S

YS

TE

M

ENGINEERING

- - -

MARINECONTRACTORS


SCALE ( A1 FORMAT )

IDENT. NO.

21-

May-2015

13:2

9:3

6...\I0

417\I0

417.0

0000\

SK-132-23-01

: MicroStatio

n






[email protected]

Tekstvak

Appendix E

0153031SK

1 : 15

GENERAL NOTES

A

GRAPHIC SCALE 0

1 : 15

1200 1500300 600 900 1800 mm

DATE:

STILL IN PROGRESS

19-Jan-2015

GENERAL ARRANGEMENT

TENDON TOP SECTION CONNECTOR

A

I0417.00000


(TYP.)

TENDON TOP SECTION

GUIDE CONE

CLAMP BOWL

GUIDE CONE

CLAMP BOWL

(TYP>)

TENDON PORCH

BALLGRAB

OPEN SPELTER

WINCH WIRE C/W

OPEN SPELTER

WINCH WIRE C/W

AA

REV. DATE DRAWN

PROJECT

SUBJECT


JOB NO. DRAWING NO.


OPS.

PR

EP

AR

ED U

SIN

G H

EE

RE

MA'S C

AD/

CA

E S

YS

TE

M

ENGINEERING

- - -

MARINECONTRACTORS


SCALE ( A1 FORMAT )

IDENT. NO.

19-Jan-2015

17:0

1:5

4...\I0

417\I0

417.0

0000\

SK-130-53-01

: MicroStatio

n






erikr

Oval

erikr

Oval

erikr

Text Box

Snag points

erikr

Line

erikr

Line

[email protected]

Tekstvak

Appendix F

0145231HI

A

GRAPHIC SCALE 0

1 : 2

40 80 240 mm120 160 200

BULLNOSE GUIDE

TENDON TOP SECTION

A

I0417.00000


MLK-012-900-CS-4018-XXXX-001


01R

AA 01R - FOR REVIEW

GRAPHIC SCALE 0 20 40 60 80 120 mm

1 : 1

100

MLK-012-900-CS-4018-XXXX-001

1 : 1

SECTION A-A

-

B-B

-

BALLGRAB

BULLNOSE

TENDON TOP SECTION

45°

C-C

-

42

47

1 : 1

SECTION B-B

-1 : 1

SECTION C-C

-

07-SEP-2015

102

19

66

17

10

12637 37

200

6

DIA.

26

DIA.

26

13

1621

2

L= 29; THREAD L = 24

TO SUIT M10 HEX BOLT

HOLE DIA. 12 (TYP].

L= 14; THREAD L = 10

TO SUIT M10 HEX BOLT

HOLE DIA. 12 (TYP].

10 122 (REF.)

15

REV. DATE DRAWN

PROJECT

SUBJECT


JOB NO. DRAWING NO.


OPS.

PR

EP

AR

ED U

SIN

G H

EE

RE

MA'S C

AD/

CA

E S

YS

TE

M

ENGINEERING

- - -

MARINECONTRACTORS


SCALE ( A1 FORMAT )

IDENT. NO.

07-Sep-2015

14:3

7:0

3...\

dms06421\

HI-

132-45-01.d

gn

: MicroStatio

n






1 : 2

GENERAL NOTES

A-A

- ISO VIEW

SEE ABOVE

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Tekstvak

Appendix G

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Tekstvak

Appendix H

53

Appendix I – Lift Design H-link Frame

The lift design is done according to the Heerema standard criteria (1):

- SC-201: ‘Single Crane Lift Systems’

- SC-291: ‘Sling, Grommet and Shackle Selection’

- SC-292: ‘Criteria for Lift Point Design’

Dry weight (𝑊𝑑𝑟𝑦) of the H-link frame, weight without contingencies and includes the weights of all

items that will be lifted except for the weight of lift rigging:

𝑊𝑑𝑟𝑦 = 170 𝑘𝑔

Design weight (𝑊𝑑𝑒𝑠), dry weight increased with weight and C.o.G. contingencies which is 10% of the

structural weight:

𝑊𝑑𝑒𝑠 = 𝑊𝑑𝑟𝑦 ∗ 1.1 = 187 𝑘𝑔

Rigging weight (𝑊𝑟𝑖𝑔), 3% of design weight:

𝑊𝑟𝑖𝑔 = 0.03 ∗ 𝑊𝑑𝑒𝑠 = 5.6 𝑘𝑔

Hookload (𝐻), load suspended from the crane hook and is defined as the sum of the design weight and rigging weight, multiplied by the factor μDAF with the Dynamic Amplification Factor: 𝐷. 𝐴. 𝐹. = 1.15 (10):

𝐻 = (𝑊𝑑𝑒𝑠 + 𝑊𝑟𝑖𝑔) ∗𝐷. 𝐴. 𝐹.

1.1= 201 𝑘𝑔

Lift points design and rigging selection, shall be based on the design hookload (𝐻𝑑𝑒𝑠) (see Figure 28) by multiply H with 1.1:

𝐻𝑑𝑒𝑠 = 𝐻 ∗ 1.1 = 221 𝑘𝑔

Figure 28: Four point lift system where the C.o.G. is indicated

𝑥 𝑙

𝑦 𝑏

𝐻𝑑𝑒𝑠

𝐹𝑣𝑙𝑝

𝐹𝑣𝑟𝑖𝑔

𝛼

𝑊𝑑𝑒𝑠

𝐶. 𝑜. 𝐺.

54

C.o.G. of the H-link frame is located at:

𝑙 = 875 𝑚𝑚

𝑏 = 579 𝑚𝑚

𝑥 = 381 𝑚𝑚

𝑦 = 290 𝑚𝑚

The load distribution factor (𝜇𝑑𝑖𝑠𝑡) follows from the location of the C.o.G.:

𝜇𝑑𝑖𝑠𝑡 = 0.375 + ((𝑙 − 𝑥) ∗ (𝑏 − 𝑦) − 𝑥 ∗ 𝑦

2 ∗ 𝑙 ∗ 𝑏) = 0.407

The vertical rigging load (𝐹𝑣𝑟𝑖𝑔) is calculated by distributing the design hookload over the lift points:

𝐹𝑣𝑟𝑖𝑔= 𝐻𝑑𝑒𝑠 ∗ 𝜇𝑑𝑖𝑠𝑡 = 90 𝑘𝑔

The vertical lift point load (𝐹𝑣𝑙𝑝) is the vertical rigging load reduced by the weight of the rigging, including

𝐷. 𝐴. 𝐹.:

𝐹𝑣𝑙𝑝= 𝐹𝑣𝑟𝑖𝑔

− (𝑊𝑟𝑖𝑔 ∗ 𝐷. 𝐴. 𝐹. ) = 84 𝑘𝑔

Rigging angle (𝛼) is 67.5° which is recommended. The following equations shall be used to determine

the loads in the rigging (𝐹𝑟𝑖𝑔) and lift points (𝐹𝑙𝑝):

𝐹𝑟𝑖𝑔 =𝐹𝑣𝑟𝑖𝑔

sin(𝛼)= 90 𝑘𝑔

𝐹𝑙𝑝 =𝐹𝑣𝑙𝑝

sin(𝛼)= 84 𝑘𝑔

To fix the slings to the H-link, 4.75 𝑚𝑇 Green Pin Shackles are used. Due to the side load of the four

point lift system, this capacity is reduced (9):

𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 = 0.7 ∗ 4.75 = 3.33 𝑚𝑇 → 𝑈. 𝐶. =0.083

3.33= 0.025

Rigging is overdesigned but inline with the rigging available on the Aegir.

Project MalikaiSubject H-link support frameJob / Bid no. I/0417Date 17-sep-15 Sheet Appendix J

PADEYE CAPACITY

Sling Load 1 [kN]

Consequence Factor 1,10

Padeye Design load Fdl: 1 [kN]

Shackle: GP4.75 47 [kN]

Pin diameter D: 22,0 [mm]

Inside width W: 31,0 [mm]

Inside length L: 76,0 [mm]

Material properties padeye:

Modulus of elasticity E: 210000 [N/mm²]

Minimum yield stress σy: 355 [N/mm²]

Minimum tensile strength σt: 470 [N/mm²]

Hardness Brinell Factor Fhb: 5,6 [-]

Padeye dimensions: SC-292

Pinhole diameter d: ((d-D)4 mm) 26 [mm] OK

Mainplate radius r1: (r11.75D) 39 [mm] OK

Mainplate thickness t1: (t1=0.25-0.40D) 15 [mm] x

Cheekplate radius r2: (r21.50D) 0 [mm] OK

Cheekplate thickness t2: (t2=0.15-0.30D) 0 [mm] OK

Weld cheek - main plate w: (w=0.1-0.15D) 0 [mm] OK

Spacer plate thickness 0 [mm]

Section length g-g 0 [mm]

Output summary:

Evaluation Governing U.C. = 0,21

Max. design load Fdl = 18 [kN]

1. d > 1.04*D --> Hertz stress check Fp = 168,6 [N/mm²]

U.C. = 0,21

2. Shear stress at section a-a Fs = 1,2 [N/mm²]

U.C. = 0,01

3. Tensile stress at section b-b Ft = 1,1 [N/mm²]

U.C. = 0,01

4. Shear stress at weld cheek plate - Fs = 0,0 [N/mm²]

main plate U.C. = 0,00

5. Tear out stress at section g-g Fs = 0,0 [N/mm²]

(Only applicable if cheeck plates are used) U.C. = 0,00

6. Shackle capacity U.C. = 0,02

Calc. Acc. To Heerema SC-292 Criteria for lift point design, Revision 0, February 2006

Allowable stress according to AISC

Seventh Revision: May 2013

b

g

g

b

a

Weld W

r2

r1

t1

t2

d

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