Dimensional Control

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 2 of 57 INDEX INDEX...2

AMENDMENTS and revisions ...5

1 Introduction...6

1.1 Scope of Work & Definition ...6

1.2 Contractual Definitions & Acronyms ...6

1.3 Responsibilities & Obligations...7

1.4 Codes & Standards...7

1.5 Company Documents ...7

1.6 Contractor Documents ...7

1.7 Procedures Document Objective ...8

1.8 Owner Specification Document...8

1.9 Contractor Procedures document...8

1.10 Dimensional Control Activities ...9

1.11 Types of Structures...9

1.12 Structural & Fabrication Terminology ...10

2 General Surveying Procedure ...11

3 Equipment ...14

3.1 General Equipment, accessories and hand tools ...14

3.2 Equipment - Site security and verification...15

3.3 Equipment Storage & Transportation. ...16

3.4 Equipment Register ...16

3.5 Computers...16

3.6 Printers...16

4 Documentation & Project Drawings ...17

4.1 Documentation Control ...17

4.2 Shop Drawings...17

4.3 Company Reference Drawings ...17

5 Precise Computerized Surveying ...17

5.1 Theoretical Structural Model ...17

5.2 Instrumentation ...19

5.3 Geometric Surveying Programs...19

5.3.1 Free Station...19

5.3.2 Resection ...20

5.3.3 Stakeout ...20

5.3.4 Tie Distance ...21

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 3 of 57

5.5 Control Network Philosophy...23

5.6 Network Control Survey Methods ...24

5.7 Checking the Reference Control Network ...24

5.8 Structural Reference Marks ...25

5.9 Instrument Position and Real Time Surveys...25

5.10 Tube marking out & references...25

5.11 Tube surveys - Instrumentation ...30

5.12 Determine the structural axis of a Tube using Instrumentation ...33

5.13 Multi-Component Tubular Alignment – Fit up or Post Weld survey...33

5.14 Beam / Column structural surveys using instruments...37

5.15 Structural Piping and interface...40

5.16 Temperature effects and correction application...40

6 Dimensional Control Process ...42

6.1 Flow Chart...42

6.2 Instrument & Survey data management ...43

6.3 Computer File data management ...44

7 SURVEYMAX - 3D geometric Program...45

7.1 General Operating System ...45

8 CAD 3D Program ...46

8.1 Rhinoceros version 4.0 ...46

8.2 Theoretical Structural Modelling ...46

9 Tolerances...47

9.1 Jacket & Deck Interface distance...47

9.2 Jacket Interface diagonal distance...47

9.3 Jacket & Deck Interface vertical position ...47

9.4 Jacket & Deck leg or column Interface spherical position ...47

9.5 Jacket Leg Straightness...47

9.6 Jacket Bracing in the horizontal plane (elevation) ...48

9.7 Deck Adjacent Legs distances...48

9.8 Deck Diagonal Legs distances...48

9.9 Deck Columns diagonal distance...48

9.10 Deck Column straightness & verticality ...48

9.11 Deck Column elevation ...48

9.12 Deck Diagonal Distance between corner Columns ...48

9.13 Deck Bracing elevation ...48

9.14 Deck Beams & Girders centre-line position ...48

9.15 Beam Flanges ...48

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9.17 Piles straightness, seam rotation, end squareness, circumference & ovality...48

9.18 Tubular Straightness...49

9.19 Tubular Local Straightness (Shell Plate) ...49

9.20 Tubular Circumference ...49

9.21 Tubular Local Out-of-roundness (Local Indentations) ...49

9.22 Ovality or Roundness...49

9.23 End Squareness...50

9.24 Node Stub locations...50

9.25 Work Point location ...50

9.26 Appurtenances...50 9.27 Anodes ...50 9.28 Padeyes ...50 9.29 Walkways ...50 9.30 Joint Mismatch ...50 9.31 Penetrations ...50 10 Reports ...51 10.1 Production Reports ...51

10.1.1 Dimensional and level inspection carried out shall be recorded...52

10.1.2 Report Sheet for Roundness and circumference inspection carried out shall be recorded ....53

10.1.3 Cover Sheet of Dimensional Control Report...54

10.2 Certification reports...55

10.2.1 Cover Sheet of Dimensional Control Certificate ...55

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AMENDMENTS AND REVISIONS

Amendment

and revision Date Page Description Yard Manager

X1 02/05/2011 Issued for IDC GS

A 01/06/2011 Issued for COMPANY Comments / Approval GS

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 6 of 57 1 INTRODUCTION

1.1 SCOPE OF WORK & DEFINITION

The purpose of this document is to describe the methods and procedures applied for Dimensional Control measurement during the construction of steel structures by Contractor.

The Methodology applied and described in this procedure can be separated into four distinct areas:-  Structural Modeling in CAD & Geometry

a) Theoretical Structural Model b) CAD programs

c) Geometric 3D data analysis

 Measurement Systems, Survey Controls & Reporting d) Instrumentation

e) Accessories & Tools

f) Geometric programs Instrumentation

g) Network Control & Geometric Surveying Control references h) Reports

 Geometric & Structural Position & Tolerances i) Vertical & Horizontal Alignment

j) Ovality & Out-of-Roundness k) Squareness

l) Shape Deformation m) Dimensions & Angles n) 3D Co-ordinates

 Project Documentation & References o) Company Specification

p) Contract Procedures

1.2 CONTRACTUAL DEFINITIONS & ACRONYMS

COMPANY

Saudi Arabian Oil Company (IK) / Aramco Overseas Company

B.V. (OOK)

CONTRACTOR Snamprogetti Saudi Arabia Ltd (IK) and Saipem S.p.A. (OOK) SUBCONTRACTOR All Subcontractors and Vendors

MAIN CONTRACT Contract awarded to CONTRACTOR

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 7 of 57 QC Quality Control DC Dimensional Control

1.3 RESPONSIBILITIES & OBLIGATIONS

Quality Control Manager verifies the document and signs the document

DC Project Surveyor Co-ordinate the inspection activities and verify the QC Report for completion. Inform the Company to verify and inspect all As Built surveys by way off a RFI document (Request for Inspection)

Dimensional Surveyor Measure the dimensions and prepare the report. Sign the report document. Inform the Company to verify and inspect all As Built surveys by way off a RFI document (Request for Inspection)

Construction Department Perform the work as per the requirements of the Contract drawings, IFC Drawings, Aramco Standard and Quality Plan

Welding Inspector Perform the welding and welders surveillance with verification of the correct application of the project WPS

1.4 CODES & STANDARDS

ISO 9001:2005 Quality Management System AWS D1.1 Steel Structural Welding Code

API RP2A-WSD Recommended practice for planning, design & constructing fixed offshore _{platform working stress design} API-RP2B Fabricated Structural Steel Pipe

API 5L Specification of Line pipe 1.5 COMPANY DOCUMENTS

Saudi Aramco Standards

SAES-M-005 Design and construction of fixed offshore platforms

DE-119893 Procedure for Structural fabrication, load-out and tie-down of offshore _structures

1.6 CONTRACTOR DOCUMENTS

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 8 of 57 00-ZA-E-G09607 Control and monitoring of Measuring Devices

00-ZA-E-G09605 Quality Records Procedure

1.7 PROCEDURES DOCUMENT OBJECTIVE

This procedure serves as a control document to ensure that the fabricated and assembled structure is maintained within the requirements of the Company’s specified tolerances. It describes in detail the methods used to undertake Dimensional Control measurement and what systems are used.

This document is specifically relevant to the surveying systems and methods adopted by Contractor in order to meet the requirements of the owners Specification Document.

It has been specifically adapted for the construction of ARAMCO Wasit Projects.

The surveys and methods defined in this document are pertinent for the use of LEICA 3D electronic Total Station series1100 & 1200 instrumentation systems.

1.8 OWNER SPECIFICATION DOCUMENT

This document describes and defines the Dimensional tolerances and the Scope of Work requirements for the project.

It specifically relates to the allowable positional tolerance of component parts relative to their theoretical design positions. In this Specification Standard, it defines the minimum and maximum out-of-position tolerance allowable as a dimension or dimensional ratio (usually in millimeters) and graphically displays some individual cases. Also, certain additional tolerances may be specified on the Project Drawings relative to a specific structural item.

Additionally, agreed dimensional limitations may be approved by the Company Project Engineer or the Certifying Authority. In either case, an agreed ‘Technical Specification’ document between the owner, certifying authority and the main contractor will be applicable to the construction of the project.

1.9 CONTRACTOR PROCEDURES DOCUMENT

This document is a contractual requirement of the Contractor as instructed by COMPANY in the Specification Document.

It refers to the MEASUREMENT METHODOLOGLY and PROCEDURES used by Contractor or sub-contractor in order to meet the Dimensional Control requirements as detailed in the owners Specification. These two documents (Company Specification and Contractors Procedures) have individual reference numbers. All Dimensional Control reports will make reference to these documents quoting the applied document numbers.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 9 of 57 1.10 DIMENSIONAL CONTROL ACTIVITIES

The primary objective of Dimensional Control is to ensure that the product conforms to the required dimensional tolerances as indicated in the owners Specification Standards document.

In order to achieve a product that conforms to the required dimensional tolerances the following surveying Activities shall be undertaken:

a) Project Structural CAD Model

b) Construction Yard Control Network reference marks b) Ground reference marks

c) Structural and component marking out and reference marks d) Temporary Support positions

e) Structural Frame layout and monitoring

f) Individual component dimensions and cut lengths g) Member alignment and shape surveys

h) CAD simulation of component & sub-assembly fit-up i) Fit-up phase surveys at sub-assembly stage (PRE-WELD) j) Secondary fit-up surveys after any necessary adjustment k) Reports of the component Fit-up Production Reports l) Recommendations for welding sequence

m) Post weld component and sub-assembled surveys n) Jacket erection phase surveys and adjustments o) Final As-Built surveys and certification

p) Structural Load out and Barge setting out and control q) Heavy lift control

The survey data information from the assembly stage will allow verification of the component lengths and positions thus ensuring the compatibility with adjoining block components.

At each of the stages, any structural out-of-tolerance will be reported and highlighted to the Production Department by way of registered reports.

Recommendations for structural adjustment or welding sequences will be made in order to rectify structural position or the effect of welding.

Post-weld or As Built surveys of the components will be undertaken once a structural block has been welded. These surveys will be documented as a Quality Control Certification Report.

1.11 TYPES OF STRUCTURES

This procedure document relates specifically to the construction of structures for the Oil and Gas Industry. These structures include, but are not limited to, the following types:

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1.12 STRUCTURAL & FABRICATION TERMINOLOGY

As built survey : Final phase of structural construction for measurement certification Barge Bumpers : Structure attached to the upper jacket to moor barges safely Beam : Primary and secondary structural support component

Boat landing : Structure attached to the upper jacket to allow personnel access Bollard : Tubular structure attached to the upper jacket for mooring boats Brace : Horizontal, vertical or diagonal tube connecting to legs or braces Buoyancy Tank : Structure attached to the Jacket to increase floatation properties CAD : Computer Aided Design graphically creates a measureable structure Caisson : Subsea conduit pipe used for seawater and cleaning waste services Can : Section of structural steel pipe with no girth weld seam

Column : Primary structural vertical tube (Leg) in a Deck

Conductor Guides : Group of guides at elevations that assist in the drilling process Conductor : Tube that guides the drilling bits and tubes

Conforming : Structural component position is within the specified tolerance limits Crane Pedestal : Tubular structure attached to the deck to support a rotating crane Deck : Main upper platform structure that supports operation services Diaphragm : Steel frame placed inside a leg or tubular to create airtight areas Elevation : Structural reference level of the Jacket or Deck

Fit-up : Initial phase of assembly with components tack welded

Flare Boom : Structure attached to the Deck to allow the burning of excess gas Girth weld seam : Tubular circumferential butt-weld seam used to join tubes together Installation Aides : Antenna and small supports to place GPS positioning systems

IR : Infrared beam of light with a narrow wave length used for measurement Jacket : Main sub-sea platform structure that supports the Deck

J-Tube : Subsea conduit piping used for services to & from the platform LAT : Lowest Astronomical Tide reference level 0.000m for the platform Leg batter angle : Inclination angle of the main jacket leg relative to the vertical plane Leg : primary structural support component of the jacket

Lifting Bollard : Tubular lug to attach crane slings for lifting purposes Longitudinal weld seam : A butt weld seam which is parallel to the axis of the pipe LWS : Longitudinal Weld Seam or Pipe Weld

Mill pipe : Structural pipe consisting of multiple cans joined by girth welds Module : Individual deck sub-structure that contains service facilities Mud-mat : Horizontal structure at the bottom of each leg reduce penetration Non-conforming : Structural component position is outside the specified tolerance limits Padeye : Crane lifting lug on the top of the jacket or deck for installation Pile : Pipe driven through the leg/sleeve to fix the jacket to the seabed

Pipe weld : Longitudinal weld seam made after the plate steel has formed a pipe Plate steel : Sheet of steel plate that is formed into tubes, cones or beams

Plate weld : Longitudinal weld seam between flat plates to make larger plates or pipe Platform : Offshore structure used to drill and process crude oil and gas

Post weld Heat Treatment : Relieves structural stress caused through the welding of a component Post weld : Second phase of assembly with the components welded

Prism : Glass or plastic with reflective qualities to aid infrared measurement Rigging Platform : temporary structure at the top jacket to assist installation offshore Ring Stiffener : Internal or external steel ring to strengthen a tubular component

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 11 of 57 Riser : Subsea conduit piping to export gas or oil under high pressure

RL : visible Red Laser beam that reflects from most surfaces without a prism Single seam pipe : Can with one longitudinal weld seam made by a continuous weld process Skid beam : Support beam that supports the Drilling module

Sleeve : Vertical tubular structure attached to a Leg to guide a pile Tack Weld : small amount of welding to join steel components at Fit-up stage Tolerance : Allowable positional displacement of a structural component

Total Station : Electronic Theodolite with computerized functions & 3D measurement

2 GENERAL SURVEYING PROCEDURE

2.1 All final As Built measurements shall be carried out by using either a Total Station theodolite or Dumpy level.

2.2 All un-calibrated measuring equipment shall not be used.

2.3 The main and sub-assemblies sketch showing the working or reference points for dimensions and elevation shall be prepared by the production supervisor, prior to any inspection.

2.4 Dimensional surveys shall be performed immediately after fit-up and after final welding. 2.5 Dimensional surveys shall also be performed on the entire structure assembly control point at a

minimum frequency of once each month.

2.6 Dimensional survey report shall be submitted to the Company’s Representative no later than one (1) days after each survey.

2.7 Reports shall highlight non conforming dimensions. The Contractor shall submit a proposed remedial action for each non conformance.

2.8 Ovality of the Jacket legs shall be measured both prior to and after Load out of the jacket and results to be presented to Company to determine the stress level of the Jacket leg can sections.

2.9 If any conflict to Scope of work or any other Company requirement, the same will prevail

2.10 During the Fabrication, the Production personnel shall prepare the correct and actual working points, centre lines and position to erect.

2.11 The simple technique to determine a correct and accurate centre line of the tubular or pipe is to use spirit level and L-square. (see: Spirit level and L-square as shown in Figure 1) The ‘x’ dimension shall represent the half pipe diameter (½Ø), the technique shall carried out on both sides of tube and the mean distance will mark the true centre-line on the top. This can be applied in the horizontal (as shown) and vertical axis (side centre-line).

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 12 of 57 i. CL Water Level L-Square

Figure 1 : Location and Reference Point

2.12 Dimensional check shall be done before and after cutting of any structural materials for fabrication. 2.13 The production personnel shall be responsible for establishing or marking the working point and

centre-line on the structure item to be check.

2.14 The established working point for dimension check shall not be changed during fabrication until completed the full fabrication.

b. The Production Supervisor and QC inspector shall check the overall dimensions and verified for straightness, roundness, etc. for the sub-assembly panel before welding work and final dimension check after welding shall be carried out by qualified dimensional surveyor.

2.15 Sub-assembly structures shall be welded adhering strictly to the welding sequence, Dimensional and levelness inspections shall be carried out before commence the welding and after completion of welding work on the panel.

2.16 The tubular centre-line & reference points on main members and branch members shall be done by using low stress die stamping to ensure permanent marking even after blasting.

2.17 A verticality alignment check of the Deck Columns shall be done by using three dimensional surveys (Total station) by a qualified dimension surveyor. For short piece such as pipe to pipe or beam to beam with less than 3 meter in length, split level may be use to check the levelness and straightness at A and B orientation as shown in Figure 2.

2.18 The straightness and levelness check shall carry out at two longitudinal planes with rotated not less than 90º

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 13 of 57 0º (A) 270 Steel Ruler 90º (B) Split Level 180º Working Point

Figure 2 : Straightness Check For tubular and Beam

2.20 The overall dimension of the structure and relative positioning of the individual sub-assemblies shall be checked by using calibrated measuring tape and precise equipment such as theodolite and dumpy level as shown in Figure 3.

2.21 Topside decks, vertical columns and other members shall be dimensionally, level and vertically inspected.

2.22 The assembly of support trusses for the main structure shall be set square and in alignment by the fabrication department.

2.23 The erection of framing or deck platform structure shall be on a flat and level surface. The main structure shall be adequately supported during fabrication.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 14 of 57 2.25 Straightness of deck column, deck bracing, girders, beams etc. during fabrication shall be measured by

using a taut string stretched or theodolite depend on the length of the item/ member and the measurement shall be made at a point of greatest deviation as shown in Figure 3.

2.26 Sizes of welding, edge preparation and joint fit-up configuration shall be measured by using welding gauge.

3 EQUIPMENT

3.1 GENERAL EQUIPMENT, ACCESSORIES AND HAND TOOLS Tape measure

Is a steel measuring gauge that is calibrated to measure correctly at 20°C.? They can be of various lengths from 3 to 100 metres

Theodolite / 3D Total Station

A precise optical instrument that is electronically operated and computer programmed. It can measure distance, horizontal and vertical angles and instantly determine the position of an object in the format of a three dimensional (3D) co-ordinate. It can store data and display results onto its own LCD screen. All data can be downloaded or uploaded into a computer using a PCMCIA memory card or ‘Flash Card’

Dumpy Level

A precise optical instrument to determine and measure the level of a component platform, sub-assembly panel etc.

Taut wire

Usually a wire that is pulled taught and straight to check and measure the alignment, straightness, levelness of a beam, pipe or tubular.

Welding Gauge

A gauge tool that is used to check and measure the weld gap size, high-low of tubular, pipe and others such as under-cut and material thickness.

Tri-Square

It is a measuring ruler to use for marking and measure the squareness. Water Level

Flexible tubing filled with coloured water and used as a gauge to measure and mark the same level at individual structural areas that are at a distance apart.

Straight Edge

It is a steel ruler use to guide and mark a straight line. Used in conjunction with a scribe marker Levelling stadia

A metrically marked measuring gauge, use together with a Dumpy Level in order to determine the level of a component.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 15 of 57 Split level & Plumb Bob

It is a piece of metal which is tied with string to measure the centre-line and alignment in between the panel.

Curv-o-mark

Specific tool used to mark the axis or angle line on a tubular component (see section 5.1) Digital Thermometer

Used to measure the temperature of a steel component that is being surveyed. The resultant temperature differences, of the steel component, can be used to quantify the thermal expansion or contraction due to the temperature changes (differences) between of separate surveys of he same component. This is only applicable to instrument surveys.

Listed and shown below are some necessary measuring accessories and hand tools.

a) Spirit Levels –300mm length b) Steel Marker Punch c) Steel Marker Scribe

d) Small steel square 150mm x 200mm e) Curv-o-Mark (tubular top dead centre) f) Small hammer

g) Chalk Line in case h) Wire brush small i) Paint marker j) Chalk marking stick k) 3m or 5m measuring tape l) 20m or 30m measuring tape m) Reflective prismatic tapes n) Carrying bag

o) Chartwell Survey book

Other items not pictured, include: p) Spike and mini prism. q) Weld gap gauge. 3.2 EQUIPMENT - SITE SECURITY AND VERIFICATION.

Apply the following guidelines for the security of the instrument

a) Checks will be made to ensure that the tripod works properly and that all bolts and screws are tensioned properly. A loose tripod component can cause the internal electro-level to malfunction and signal an operating error. It will also give inaccurate results even over short distances.

b) Verification of the instrument Calibration option will be made on a regular basis. Set up the instrument on one face and adjust the electro-level bubble to within a 2” range. Rotate the 180deg to the opposite face and check if it is within a 5” range. If it is not, then apply the Calibration option.

c) Check periodically that the Laser Red light is in alignment with the telescope axis. This check is obligatory after transportation over a long period.

d) When the instrument is set up ensure that it will not interfere with other engineering activities.

e) Always ensure that the instrument is attached to the tripod by means of the tripod/tribrach screw attachment.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 16 of 57 f) Do not allow other third parties to touch or use the instrument.

g) Check and be aware what is happening within the vicinity of your working area.

h) Never set up the instrument with welding or other cables straddling the tripod legs. If they are pulled they may interfere with the tripod legs and pull the instrument over.

i) Never leave the instrument unattended in a busy engineering environment. If necessary cordon off the instrument area with hi-viz bunting tape.

j) When coordinating the instrument position, within a Network Control System by the resection method, always check into a third control point to verify the positional accuracy.

k) Ensure that, when using the instrument in the reflectorless mode (laser distance) make sure that the beam is not no interference of the distance takes place.

l) At the termination of the survey check into a Network Control reference station to verify that the instrument position has not moved during the course of the survey. If the results are not satisfactory carry out another complete structural survey.

3.3 EQUIPMENT STORAGE & TRANSPORTATION.

a) All survey instrumentation items will be kept in a secure, ordered and dry environment. b) Instruments will be regularly cleaned and made dry prior to storage.

c) Instruments will be made secure during transportation and if necessary placed into a padded cardboard box for extra protection.

3.4 EQUIPMENT REGISTER

A register of all surveying and measuring equipment will be established by the Quality Control Department. It will list the equipment item, reference number, relevant documentation and calibration/servicing records. 3.5 COMPUTERS

Portable computers (laptops) are used to generate complex 3D geometric CAD drawings of the theoretical structures. For security all survey data shall be downloaded into remote Data storage units to ensure that important records are retrievable.

3.6 PRINTERS

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 17 of 57 4 DOCUMENTATION & PROJECT DRAWINGS

4.1 DOCUMENTATION CONTROL

A filing system shall be established to maintain an ordered control of all survey related work and correspondence. This section refers specifically to all paper generated documentation. For computer generated documentation, see section 6.2.

Main Files shall be numerically marked and titled. Titles will include the following: - 1. Specification, Standards and Procedures.

2. Correspondence. 3. Equipment Register.

4. Methodology Statement and Equipment Instruction documents. 5. Reference Control Network.

6. Production report register 7. Certification report register

8. Structural surveys register per Block or major unit. 9. Node Surveys

10. Setting out Register.

11. Piping or Tubular survey register 12. HSE safety Documents & Procedures 13. Load out barge and sea-fastenings 14. Site Surveys

All Files shall contain a covering Index or Register sheet which will log the documents in consecutive number order and date entry.

4.2 SHOP DRAWINGS

All construction surveys will be relative to the shop drawings. In the event of a drawing error, or lack of structural detail, the engineering office will be informed.

These drawings will be in A3 format and will be kept in various titled files in order to separate and isolate individual structures. Strict control will be maintained by the issue of revisions and the updated current Construction Drawing List. Superseded drawings will be discarded. If drawings are required for site work then a copy will be made from main file register. No original file drawing will be removed from the office.

4.3 COMPANY REFERENCE DRAWINGS

These drawings (Project Drawings) will be in A3 format and kept in its own filing system. They will be used for reference only.

5 PRECISE COMPUTERIZED SURVEYING

5.1 THEORETICAL STRUCTURAL MODEL

The principle philosophy of modern construction measurement is being able to compare the actual structure and components to the theoretical designed concept. The methodology applied herein requires a complete structural model of the structures to be developed in CAD. This model will be developed as a vertical structure and based on the construction drawings. (see typical models below)

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Additional structural models will be developed with structures in the horizontal position and as individual Rows. Individual structural elements such as Boat Landings, Barge Bumpers, Elevations and Conductor Frames can be created from the principle structural model in the vertical.

All surveys of actually fabricated individual components and main structural elements will be developed in CAD and will be compared to their relative theoretical models. The accuracy of the actual fabricated components will be determined and quantified by this comparison.

Zulf 480 Jacket in 3D

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 19 of 57 5.2 INSTRUMENTATION

Modern electronic theodolites, also known as ‘TOTAL STATIONS’, will be used to undertake surveys. Their precision and functionality ensures dimensional accuracy and capacity to record data in order to meet the requirements of the client’s specification and approved structural tolerances. These types of theodolites contain integral geometrical surveying programmes and have a specified measurement accuracy that is higher than the minimum structural tolerance as required by the owners Specification document.

Total Station manufacturer LEICA Geosystems - Switzerland

Series TPS1100 & 1200

Type TCRA1101 & TCRA1201 Computerised / Electronic

Angle Accuracy 1”

Distance accuracy Infrared 2mm Distance accuracy Laser 3mm

Memory card Compact Flash card 32MB Working temperature range -20deg C to +50deg C

Calibration. Self-calibrating corrections to manufactures.

Leica instruments have a Laser measurement function (RL) which allows a distance to be taken to inaccessible points or structural locations. The measured slope distances and the instruments electronic vertical and horizontal angles are recorded automatically. The point co-ordinates are instantly calculated recorded in the PCMCIA memory card and displayed on the LCD screen.

5.3 GEOMETRIC SURVEYING PROGRAMS

The instrumentation (Leica) contains internal geometric programs that are applicable to Dimensional Control and are used to position the instrument and measure to the structural components:

 FREE STATION co-ordinates the position of the instrument using 3 reference stations  RESECTION co-ordinates the position of the instrument using 2 reference stations  STAKEOUT sets out a point from a co-ordinated instrument (2D or 3D model)  TIE DISTANCE calculates a distance between two surveyed points or more

5.3.1 Free Station

This Program uses three Control Network reference stations to position the instrument (X). The first two reference stations (e.g. R5 and R10) are used will position the instrument within the Control Network. The instrument automatically searches for the co-ordinates of all three stations that are filed in the instruments PCMCIA data memory card.

Then, the instrument will prompt to operator to input the reference number (e.g. R17) of the third reference station. Once this is co-ordinate is entered the instrument will automatically turn to the reference station and it is observed. The residual errors will determine the positional accuracy.

See Fig. A.

If the program fails to calculate this is due to incorrect station data or station/reflector selection. If this happens, the ERROR box will display. (See ERROR DISPLAY section 7.4).

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 20 of 57 Known R5 Co-R1 Known Co-R5 & R10 are used to calculate the position of STN Third Station 5.3.2 Resection

This program and the screen display is similar to the ‘FREE STATION’ program but uses only two stations. There is no calculation (‘CALC’) function necessary with the RESECTION program.

5.3.3 Stakeout

This program allows an individual point (Pnt. 2) or a number of points that have known co-ordinates to be positioned and SET OUT within a related network control co-ordinate system (R5 & R10).

STN X R1

Known Calculated

Co- Co-ordinates

Fig. A – FREE STATION uses two Stations (R5 & R10) to calculate and one to verify (R17) the position of STATION X within the Control Network.

R5 R10 Known Known Co- Co-ordinates R5 & R10 are used to calculate the position of STN X Calculated Co-ordinates STN X

Fig. A – RESECTION uses two Stations (R5 & R10) to calculate the position of

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 21 of 57 5.3.4 Tie Distance

This program measures the distance between two points and has two methods of calculation and display.

Methods: POLYLINE or RADIAL mode

POLYLINE Mode allows the measurement between consecutive sets two points.

Results : Distances A to B : B to C:

RADIAL Mode measures the distances from a single point to other individual points

Pnt.2 R5 R10 Known Co-ordinates Known Co-ordinates STN X Calculated Co-ordinates RESECTION R5 & R10 are used to calculate the position of STN X Point to STAKEOUT Known 3D Co-ordinates

Fig. A – STAKEOUT 3D will automatically rotate to the Pnt.2 position using the calculated

bearing. The distance is verified by measuring in RL or IR mode to the surface or a target. The program will display the position error.

B

A

_{Distance 2}

Distance 1

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 22 of 57 Distance 1 Distance 2

A

B

C

Results: Distances A to B: A to C: 5.4 CALIBRATION

The calibration of the instrument is initially set in the manufacturers’ factory. These are known as the FACTORY SETTINGS. The instruments are standardized to measure correctly at 20degrees Centigrade and all angular alignment CORRECTION values are ZEROED.

Each instrument will be calibrated and serviced annually and hold valid manufacturers’ or approved agents’ ‘Certificate of Calibration’ document. This document will be filed in the Contractor QA/QC departments’ Equipment Calibration Register. A copy of the certificate will be made available for the client.

The instruments have an integral operating system that allows the instrument to calibrate. This self-calibration operation is located in the Main Menu, INST. CALIBRATION.

This function will verify all the instruments angular values or errors and adjust the CORRECTION values accordingly.

The Instrument Calibration function checks the following angular attributes of the instrument:- a) l & t - Compensator (electro-level bubble) Longitudinally and Transversely b) i - Vertical Index error

c) c & a - Horizontal Collimation error & Tilting Axis d) i / c / a - Index – Collimation - Axis

All of these corrections will be checked on a regular basis and recorded. Standard Distance corrections or PPM corrections (Parts Per Million)

Leica instruments are calibrated and set in the factory (Factory Settings) to measure at the Standard distances. They contain an internal program which allows the operator to take account of and input the current ambient atmospheric conditions (atmospheric pressure and ambient temperature). The measuring system uses infrared light and red laser light to measure distance, but the speed of these two light mediums are not constant. They are affected by the pressure and temperature of air. The resultant atmospheric PPM correction will be applied for each survey. The instrument will automatically adjust the measured distances to the Standard factory settings.

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5.5 CONTROL NETWORK PHILOSOPHY

A REFERENCE CONTROL NETWORK shall be established within the Construction Yard and the various Workshops. The primary function of the Network is to act as a permanent referencing system in order to position accurately (in any location) the Instrument measuring equipment.

The Control Network will allow the operator to be dimensionally IN CONTROL of the SPACE about the structure.

A Control Network is a group of co-ordinated survey stations (points) that have known three-dimensional (3D) co-ordinates (E: N: Z) relative to a common geometric grid.

The Control network survey station can be Pillar station or adhesive reflective prismatic target. They shall be permanently fixed at structurally stable locations throughout the project assembly areas. The Control Network is used to accurately reference and co-ordinate a surveying instrument relative to the theoretical structural model. The three dimensional positional accuracy of the instrument within the Control Network will be +/-1mm.

Site Control Network Stations in RADIAL format Site Control Network

with the jacket position

The survey stations shall be surveyed to an accuracy of 0.5mm and form the basis for structural measurement control. The coordinated network shall be relative to the theoretical structural design. Therefore, during the course of the structural assembly each component can be surveyed to verify its actual position relative to the theoretical model.

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Ground Pillar Control station no. 2 with a circular prism. Prismatic reflective stations G1 & G2 are positioned on the pillar.

A reference control network of survey stations shall be established at each fabrication area and the main assembly area. The network survey stations shall be located in areas of high visibility. Important care must be taken to ensure that the locations will be unaffected by movement including linear thermal expansion or contraction. Each point will be individually code referenced (e.g. A01, A02 etc). In certain cases concrete pillar stations or ground marks shall be used where visibility is limited.

The Network shall also be used to monitor structural movement (shrinkage, expansion, subsidence or accidental movement) of the components and the structure.

The position of the structure and its co-ordinates in the construction yard will be relative to the Network Control co-ordinate system.

All CAD models of the structure (in Rhinoceros) shall be positioned to the same co-ordinate system as the Network Control

5.6 NETWORK CONTROL SURVEY METHODS

The control stations shall be surveyed in groups, as it is normally impossible to view all the survey stations from a single position.

The initial survey shall incorporate the longest possible visible base line (station to station). This first survey shall be the primary FIXED base-line survey and shall be surveyed at least three times until the residual errors are less than 1mm.

The base line shall be incorporated into subsequent group surveys. In order to quantify the co-ordinates of each survey station it shall be necessary to surveyed them at least three times from different locations. Each group survey will be superimposed over initial survey and a best-fit 3D geometric coordinated system will be created.

Residual 3D errors from these surveys should not be more than 1mm per survey station point. 5.7 CHECKING THE REFERENCE CONTROL NETWORK

The Survey Stations shall be checked on a regular basis (usually monthly) to ensure the accuracy and stability of the Network. The results of each survey shall be recorded & documented in the Survey Control Network File. Each survey shall indicate the accuracy obtained and highlight any ambiguity or difference to the original data.

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Procedural checks shall be made during the course of normal engineering survey activities. In these cases individual survey stations will be checked against their current co-ordinates.

5.8 STRUCTURAL REFERENCE MARKS

Reference Marks or Work Points shall be placed on the structure at major structural intersection positions. These points shall be marked on a sprayed white paint surface, hard punched and reference numbered for easy identification and visibility. Each Reference Mark shall have its own theoretical 3D co-ordinate (Easting, Northing and Elevation) relative to the Structural Model. An actual As-Built survey of these points shall be undertaken in order to determine the ‘Best Fit’ axis line position of the structure.

5.9 INSTRUMENT POSITION AND REAL TIME SURVEYS

The Instrument can be positioned accurately within the Reference Control Network by using the internal ‘RESECTION’ program. Two known Reference Survey Stations will be surveyed in order to co-ordinate the instrument within +/-1mm.

In addition, real-time positional surveys of structures can be made as they are being moved into their theoretically correct locations.

5.10 TUBE MARKING OUT & REFERENCES

Reference marks will be created on a structure in order to identify the actual positions for a column or tube. They mark the following: - centre-line, axis, ¼ line, work point, elevation, profile development line, tubular circumferential line, penetration and cut-line. The importance and accuracy of the marking-out of these points is fundamental to the overall dimensional quality of the structure. Care and accuracy will be applied at all times during the marking out process. All marks will be clearly punched, scribed and identifiable for permanent usage during the construction phases.

The points to be marked out will be recorded on a sketched sheet noting the dimensions and angles used. The original sketches will be signed, referenced numbered, checked and filed in the Setting-out Register. They mark the following:-

a) Beam or Tube centre-line. b) Tube ¼ lines.

c) Work point (structural intersections on a Node). d) Structural Elevation.

e) Profile cut line or shape development line.

f) Tubular circumferential line, penetration and cut-line.

The importance and accuracy of the marking-out of these points is fundamental to the overall dimensional quality of the structure.

Care and accuracy must be applied at all times during the marking out process. All marks must be clearly punched, scribed and identifiable for permanent usage during the construction phases.

Tube Measurements

In order to mark out the reference lines and Work Points the first objective is to measure the dimensions of the tube. These measurements are:-

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Longitudinal Weld Seams

a) The tube length, bevel-to-bevel or flat end to flat end, at each side. b) The circumference at both ends using a flat 20m or 30m tape. c) The tube wall thickness.

d) All horizontal or longitudinal weld seam positions. e) Note the identification number.

f) Internal diameters (orthogonally positioned).

Setting out a ¼ line using a ‘Curv-o-mark’ Outside surface circumference Tube bevelled at both ends Diameters Circumferential Weld Seam

Tube non-bevelled (flat ended) at both ends

Length Wall Thickness

The flat profile tape is placed around the Tube end and straightened. The circumference measured at the 100mm mark is 4.251m. True circumference

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All this information will be drawn and recorded in a Survey note book (Chart well Survey Book) Marking out

Tube ¼ Lines

Definition: - These are reference lines, on the exterior or interior surface of a tube, that are set at 90 degrees relative to each other and parallel to the axis of a tubular pipe. Their circumferential position is determined by the position of the longitudinal Weld Seam. See Fig. D

Usage: - The four-quarter reference lines of a tube are marked in order to position other members that join the main tube.

The positions of these lines are set out relative to the design drawings. The drawings will show the position of the lines relative to the longitudinal weld seam.

.

Fig. D - A sectional view of a tube: showing a 45deg weld seam with four-quarter lines.

Method of marking

a) Measure the circumferences at both ends.

As tubular pipes are never exactly fabricated to their correct theoretical diameter, it is important to measure the actual circumferential distances at both ends of the tube.

b) Calculate the arc distances for the ¼ lines and weld seam angle.

180° ¼

0° ¼

Tube diameter = _{L / Weld seam at 45 deg}

1 000m

90° ¼ line 270° ¼ line

¼ to ¼ line arc dist. = 785.5mm Tube Circumference arc dist. =

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 28 of 57 If the tubes’ circumferential arc distance is 3.142m, then the ¼ lines are equal to 785.5mm arc distance. The 45 deg. L / Weld to ¼ line will be 393mm.

c) To calculate the theoretical arc distances use the formulae: - 2 x π x r = circumference (Where: - π = 3.14159 ; where: - r = radius of the tube)

Note: Definition of Pi or π: - is a geometric constant and is the numerical ratio of the diameter to the circumference of a circle. Pi ratio value is approximately 1 to 3.14159. Therefore, if the diameter is 1.000m then the circumference is 3.14159m.

Circumference

d) In chalk, set out a ¼ -line parallel relative to the Tube axis and the longitudinal weld seam. Use a Curv-o-mark or spirit level and metric tape to set the first line.

e) Check all the circumferential distances that are marked.

If they are correct, then proceed to punch mark the lines, as shown in the photograph below.

g) Mark out, using a hammer and punch, the 100m end reference points and the Work points (as shown in the photograph below).

Marking out of a Work Point.

Diameter =1.000m

Circumference Rolled out = 3.142m Diameter

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g) Check all dimensions and then reference the lines & WP in paint.

Marking out of a ¼ line, at 45 degrees from the longitudinal weld seam, on a 1-metre diameter tube.

h) Sketch and Record the data in the survey book.

The points marked will be recorded on a sketched sheet noting the dimensions and angles used. The original sketches will be signed, referenced numbered, checked and filed in the Setting -out Register.

The marking out of a reference point exactly 100mm from the

bevelled end of a tube. The points are punch marked and then reference painted.

The Curv-o-Mark is used to mark set-out a point on a tube and then develop a line so that it is parallel to the axis of the tube.

In order to mark a horizontal or vertical position on a tube, the rotating angle gauge has to be aligned correctly to the reference lines at 0 degrees or 90 degrees. ENSURE that the orientation reference line, on the face of the gauge, is aligned with the required bubble angle.

1. For the horizontal or side position set the reference line to coincide with the 90 degree arc position. 2. For the vertical, top or bottom position set the reference line to coincide with the 0 degree arc position.

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Setting the bubble to 90 deg in the Horizontal position

CURV-O-MARK orientation reference Line

Setting the bubble to 0 deg.

Once the bubble is centred, using a light hammer hit the top of the sliding pin to mark a first reference point. This will punch a small mark into the steel tube side wall. Without moving the central rotating gauge, turn the centre finder 180 degrees to view the bubble on the opposite face. Place the sliding pin point close to the first point. Once the bubble is centred, hit the sliding pin at the top to mark a second point. The MEAN of the first and second reference points will be the MEAN / true position of the tube axis line. Mark this mean point with a larger punch mark and chalk reference.

in Vertical position

Repeat this marking process at the other end of the tube or at the locations where the tube alignment has to be determined.

5.11 TUBE SURVEYS - INSTRUMENTATION

Tube surveys are carried out in order to determine accurately the: -

Rotating Bubble

Rotating Angle Gauge

Feet supports

Top of Sliding Centre Pin

CURV-O-MARK orientation reference Line

Centring Pin Marking Point

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 31 of 57 a) best-fit centre-line (BFC) of a steel tube or of connecting tubes

b) an actual axis intersection point (WP) or (IP) c) tube lengths

d) ovality

e) out-of-roundness f) circumference

g) weld seam locations, circumferential and longitudinal

Method 1 of surveying on the outside surface

a) Individual points can be surveyed on a pre-marked circumferential line on the outside surface of a tubular using the instrument’s laser reflectorless function (RL).

b) Survey the ends 100mm reference points – in order to determine the tube length

c) The circumferential line must be perpendicular to the axis of the steel tube. For best results it is better to mark a circumferential line either in chalk or paint in certain cases, it is also possible to follow, at an offset, the circumferential weld seam of the tubular. In this instance, positional care of the laser must be taken and follow an offset line of at least 20 to 100mm from a circumferential weld seam. This is due to the distortion of the tubular within close proximity of the weld seam area.

d) For accurate results, it is best to take a minimum of eight evenly spaced positional laser or infrared readings/shots around the tube on a pre-marked circumferential line.

Method 1 of surveying on the outside surface

e) The number of surveyed positions depends on the diameter of the tube. The greater the tube diameter will mean the greater the number of points necessary to be surveyed.

f) These results are processed in the ‘Circle Fit’ option of the ‘SurveyMax’ 3D geometric program. Each GROUP of points is processed and the data results indicate the tube radius at each point and the overall mean tubular radius. This will determine the best-ft Centre (BFC) and detail the radius of each point surveyed. An acceptable survey result will show these radii to be within 3mm of the theoretical radius of the tube.

Group 1 > 10 Group 11 > 20

CL

Laser shot locations in RED

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g) The accuracy of the survey and the form shape of the tubular can be immediately compared to the theoretical radius.

h) Out-of-Roundness and Out-of-Circularity can be determined using this method.

Method 2 of surveying at the open ends

a) Place a minimum of 4 or 5 reflective targets (magnetic prismatic cubes) at each the end of the tube.

Best-Fit-Centre(BFC)

Prism targets

Make sure that the face of each target is exactly placed at the end of the tube, on the bevel or flat end. b) Using the instrument (co-ordinated into the local Control Network) survey the inside diameter of the tube

at each target prism position. Survey both ends of the tube.

c) The results are processed in the ‘Circle Fit’ option of the ‘SurveyMax’ 3D geometric program. d) The Circle Fit will calculate the centre co-ordinates of the targets (the centre of the tube).

Method 2 of surveying at the open ends

An example showing reflective prisms placed at one end of a recently rolled tubular. These prism locations will determine the Best-Fit-Centre of the tube end - BFC.

IMPORTANT

Do not place the targets within 100mm of the longitudinal weld seam. There is a tendency that the tube circumference shape in this area can be flattened out.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 33 of 57 Weld Targets 200mm

5.12 DETERMINE THE STRUCTURAL AXIS OF A TUBE USING INSTRUMENTATION

For accurate results it is best to take a minimum of 8 evenly spaced positional laser or infrared readings/shots around the tube on a pre-marked circumferential line. The number of surveyed positions depends on the diameter of the tube. The greater the tube diameter will mean the greater the number of points necessary to be surveyed.

These results will be processed in the ‘Circle Fit’ option of the ‘SurveyMax’ 3D geometric program which determines the best-fit centre. Each point is processed and the data results indicate the tube radius at each point and the overall mean tubular radius. The accuracy of the survey and the form shape of the tubular will be immediately compared to the theoretical radius. Out-of-Roundness and Out-of-Circularity will be determined using this method.

5.13 MULTI-COMPONENT TUBULAR ALIGNMENT – FIT UP OR POST WELD SURVEY

Detailed below is a practical and accurate method for surveying the alignment of Jacket legs, Piles and Tubular sections, without the need for network positioning or office processing.

Results can be given on site at the location of the component being measured.

It will provide results of the components alignment and display results on the instruments LCD screen:- 1. Direct offset errors of the tubular sections relative to the actual tubes’ zeroed reference points. 2. The alignment results, for both the Vertical and Horizontal alignment of the tubular sections, are

displayed on the instruments LCD control panel screen showing in co-ordinate format the easting co-ordinate [theoretically 0.000E] and the height [theoretically 0.000Z] of each point surveyed.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 34 of 57 Objective:

1. Measure the vertical and horizontal alignment and lengths of two or more tubular sections before welding (FIT-UP) or after welding (POST WELD).

Equipment:

1. Leica TCRA electronic theodolite with laser measurement.

2. Curv-o-mark, 3m tape, Spirit level, chalk marker, cubic reflective tape. Method:

1. Mark out the five reference points A, B, C, D, E using a Curv-o-Mark, spirit level, 3m tape, chalk and marker.

2. Check the OVALITY of the Tubes in the VERTICAL and HORIZONTAL axis at each end to ensure they are within tolerance - (Dmax – Dmin tolerance = +/- 6mm)

3. The Curv-o-Mark has to be used on two faces. (see method section 5.1)

4. Points A, B, C and E will be marked 100mm from their corresponding bevels. All the marks including point D, see section figure below, will refer to the side (90° - side ¼ line) and top (0° - top ¼ line) quarter-lines.

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6. Set the Electronic theodolite instrument within 10 metres of the tubular to be measured.

7. Use the ‘TIE DISTANCE’ program, measure the slope distances between the reference points (A > B > C > D > E)

8. Record the levels and level differences of the reference points (A, B, C, D, E). 9. Select two of the reference points as ZERO datum for the alignment (A and E)

10. Apply 0.000E co-ordinates to points E and A. This will mathematically give the bearing from point E to A as 360º

11. Apply 0.000N and 0.000Z to point E.

12. Use program ‘RESECTION’ to co-ordinate the instrument using the applied co-ordinates point A and E. Input the co-ords of the reference stations manually into the program when prompted.

A B C D E Inst. Set up Inst. Set up A B C D E A < E bearing 360º (Tie Distance A > E = 35.055m)

Apply Co-ords. for Point E. 0.000E 0.000N 0.000Z Apply Co-ords. for

Point A. 0.000E 35.055N 0.015Z 0º line Spirit Level Check dimension 90º Line Curv-o-Mark References A-B-C-D-E

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Survey results and analysis:

Bevel to bevel – distance = 35.255m

Results

1. Horizontal alignment (90°) - (Easting displacement from references – View from above)

Results

2. Vertical alignment ( 0° ) - (Height displacement from reference - View from above)

3. An additional survey check would be to take levels on the top or bottom ¼ line to verify the vertical alignment.

4. The lengths of the tubular sections can also be deduced by analysing the Northing co-ordinates of each point and adding the 100mm reference distances to obtain the overall lengthens, bevel to bevel or square end.

Fit-up Alignment Survey - Location of Reference Points

B C A D E Inst. Set up Points A to E – distance = 35.055m Point E. Co-ords. 0.000E 0.000N 0.000Z Point A. Co-ords. 0.000E 35.055N 0.001Z Point B Co-o 0.006E Point C Point D Co-ords. 0.007E Co-ords. rds. 32.205N 0.006Z 0.005E 32.000N 17.000N 0.005Z - 0.002Z + E 0 0 5 6 7 A B C D E +1 +6 +5 -2 +0 A B C D E N - E

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 37 of 57 These points are accurately set-out on the side of the cans and verified.

Case 1 – with two singular cans – at one fit up location

Case 2 – with two single cans welded with a single can – at one fit up location

Case 3 - with three single cans welded with three single cans welded– at one fit up location

Note: All previously welded cans must have a Post Weld Certificate that certifies the alignment as conforming. Straightness tolerance = 1mm per 1m up to 10mm for lengths in excess of 4m

5.14 BEAM / COLUMN STRUCTURAL SURVEYS USING INSTRUMENTS

Description

Steel beams and columns are used to construct Deck structures.

Most deck structures are rectangular in design and are composed of beams welded together forming frames at each elevation. The frame is strengthened at the main intersections by the insertion of Structural NODES.

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There may be many elevations within a deck structure and the number depends on its facility and design function. Each elevation will have vertical beams (columns) or tubulars welded at structural intersection points. These columns will support the next elevation directly above.

Fabrication and surveying of a deck frame commences at the FIT UP assembly stage. None of the beams are fully welded together at this stage.

Surveying commences with marking the structure: a) Centre node points.

b) End of beam centres at 100mm off set from the bevel.

_{Part of a Deck Frame}

being fabricated in the workshop. Note the Joint position and in the centre will be marked the structural Work Point - (WP).

The next stage is to place the targets at each of the reference points and survey them relative to a local Control Network.

Reflective Target - CUBE

The top of a Node Joint. The Work Point (WP) is marked by a prismatic tape Target.

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The WORK POINT is the centre of the node structure and is set-out and pop-marked. The adjoining beams have to be aligned to this central point.

Shown below is the end of beam reference point. It is positioned 100mm from the bevel end and the centre line of the beam.

This position is relative to the design AXIS (centre-line) of the deck elevation. The design drawings refer to this point as the Top of Steel (TOS). For the Structural model, this point relates to the WIRE FRAME design. The actual elevation for this particular TOS is Elevation +12.000m.

Centre of beam –reference point exactly 100mm from the bevel end.

It is important that the marking out of centre of a beam or the intersection of beam and column joints (nodes) are referenced correctly.

The construction drawings indicate the dimensions between the structure relative to the centre line and intersection of the

A beam/column centre or intersection position can be determined by locating the flange centres and flange ends using the ‘DIST’ then ‘REC’ function of the instrument.

The distance (‘DIST’) is measured first to within 5mm visually of the beam end.

The instrument telescope axis is then moved horizontally to the beam end/side position and the measured horizontal bearing is recorded (‘REC’).

These individual points can be processed in the ‘SurveyMax’ 3D geometric program and exchanged to the CAD program by DXF file.

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DOCUMENT Nr. 00-ZA-E-G09611 Rev. 00 Date 02.01.2012 DIMENSIONAL CONTROL PROCEDURE Sheet 40 of 57 The beam can then plotted and its actual position relative to the theoretical model can be determined. Three dimensional vector arrows will indicate the actual position from its theoretical position.

Beam elevations can be determined by measuring directly to the surface of the structural element using the laser (RL) function.

A basic Deck structure with 2 elevations joined by vertical and diagonal tubular columns.

5.15 STRUCTURAL PIPING AND INTERFACE

The surveying techniques used to position piping elements are similar to those described in 5.2. An additional requirement is to determine the pipe end bevel and will be achieved by measuring to the 100mm reference marks or to the best-fit centre of the bevel. These surveys are useful in determining any pipe over or under length as well as position.

5.16 TEMPERATURE EFFECTS AND CORRECTION APPLICATION

All steel structures are affected by the ambient temperature and more importantly by direct sunlight exposure. Ambient temperature change upon a steel structure will affect it uniformly. Whereas, direct sunlight will significantly deform a structure. The effect of both of these thermal conditions on a steel structure will be taken into account when considering measurement or positional setting-out. Additionally, local structural heating due to welding activities can also have an effect on overall measurement and structural shape. The design dimensions for the steel structures and measuring tapes are standardized to the temperature of +20deg C. Therefore, when measuring between two connected points using a calibrated measuring tape or steel band it will not be necessary to apply a temperature correction to the measured dimension. However, when surveying by instrumentation it will be necessary to apply a correction factor to the calculated distance between the same two connected points.

In order to determine the correct distance the temperature of the steel must be known. The correction factor will be: -

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Correction factor to the measured distance = (20 - ST) x (C x D)

where: -

20 = standardised structural temperature 20° C ST = Steel Temperature in °C

C = Coefficient for the linear expansion of carbon steel = (0.0000125)* D = Distance measured at steel temperature

* Variable depending on the class of steel. Example:

D= 30m : ST = 40°C :

Correction factor = (20 – 40) x (0.0000125 x 30) = -0.008m

Therefore, True distance at 20°C = (30.000m – 0.008) = 29.992m

The effect of direct sunlight (solar radiation) on a steel structure in terms of structural movement is significant. With an ambient temperature in the shade of 30deg C the actual surface temperature of steel exposed to direct sunlight can be as high as 60 to 70deg C.

This solar absorption creates a structure with surfaces of differing temperatures. One side of the structure will be considerably warmer that it’s opposite side.

The locations, of this thermal absorption, also changes throughout the day light hours.

This daily effect will cause the structure not only to change longitudinally but more significantly to bend laterally.

Consequently, under these conditions the value of surveying steel structures accurately becomes very limited. Therefore, when surveying a structure that is exposed to direct sunlight the general applications and conditions to apply will be as follows: -

a) Survey a large structure during the early hours before sunrise.

b) Measure and record that the surface temperature of the structure at several locations at beginning and end of the survey. Verify that it is evenly distributed.

c) Mark the structure with fixed reference points and incorporate these points into the structural survey. They will be the ‘MONITORING POINTS’.