IC-QA-NG71 Guide to QA Specification G71 Construction Surveys

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Edition 2 / Revision 0 TRANSPORT FOR NSW December 2020 TRANSPORT FOR NSW (TfNSW) SPECIFICATION GUIDE NG71 GUIDE TO QA SPECIFICATION G71 CONSTRUCTION SURVEYS REVISION REGISTER Ed/Rev Number Clause Number Description of Revision Authorised By Date Ed 1/Rev 0 Initial issue GM, RNIC 09.02.05 Ed 1/Rev 1 Various Revisions made to specification clauses in line with revisions to RTA G71 GM, RNIC 29.03.06 2.1 Additional guide notes provided 3.4 Guide notes provided for new Specification Clause 3.4 Ed 1/Rev 2 Global Minor editing to clarify intent. GM, IC 01.09.09 Part I - Guide Notes and Model Procedures Clauses in Guide Notes and Model Procedures now numbered with prefixes “A” and “B” respectively. Table NG71.1 (a) Title changed. Correction for spheroid/geoid separation (N) added. Global Acronym “GPS” replaced by “GNSS” in all cases. B1.2.3 Class D changed to Class E. Table NG71.1 (c) Title changed. Criteria for residual in angular measurement column changed. Correction for spheroid/geoid separation (N) added. Acceptance criteria in “Calculations” column changed to “The software must provide evidence that the local uncertainty is less than 4 mm.” Footnotes to Table changed in line with changes in Table. B1.3.2 Class changed from “LB” to “LA”. B2.3 Item (d) changed to include atmospheric correction. Table NG71.2 Order of Accuracy “6H” deleted. “Estimated Accuracy” changed to “Local Uncertainty”. Requirements adjusted. Ed 1/Rev 2 (cont’d) B2.5.1 Information about differential levelling clarified.

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IC-QA-NG71 Guide to QA Specification G71 Construction SurveysTRANSPORT FOR NSW (TfNSW)
REVISION REGISTER
Ed/Rev Number
By Date
Ed 1/Rev 0 Initial issue GM, RNIC 09.02.05
Ed 1/Rev 1 Various Revisions made to specification clauses in line with revisions to RTA G71
GM, RNIC 29.03.06
3.4 Guide notes provided for new Specification Clause 3.4
Ed 1/Rev 2 Global Minor editing to clarify intent. GM, IC 01.09.09
Part I - Guide Notes and Model Procedures
Clauses in Guide Notes and Model Procedures now numbered with prefixes “A” and “B” respectively.
Table NG71.1 (a)
Global Acronym “GPS” replaced by “GNSS” in all cases.
B1.2.3 Class D changed to Class E.
Table NG71.1 (c)
Title changed. Criteria for residual in angular measurement column changed. Correction for spheroid/geoid separation (N) added. Acceptance criteria in “Calculations” column changed to “The software must provide evidence that the local uncertainty is less than 4 mm.” Footnotes to Table changed in line with changes in Table.
B1.3.2 Class changed from “LB” to “LA”.
B2.3 Item (d) changed to include atmospheric correction.
Table NG71.2
Order of Accuracy “6H” deleted. “Estimated Accuracy” changed to “Local Uncertainty”. Requirements adjusted.
Ed 1/Rev 2 (cont’d)
B2.5.1 Information about differential levelling clarified.
ii
By Date
Table NG71.3
Notations changed for clarity. “Estimated Accuracy” changed to “Local Uncertainty”. Requirements adjusted. Notes restructured for clarity.
Part II - Commentary
Text from G71 specification updated due to changes in base document.
Table G71.1 Guide notes on Class and local uncertainty in accordance with SP1 added.
2.3.2 Guide notes on Lands Department document Control Survey and SCIMS added.
3.2 Reference to RTA G2 deleted from Guide notes.
4.1 Words “Apart from surveys for the survey control network” added to Guide Notes.
4.2 Guide notes on the relationship between Orders of Accuracy in previous versions of the Specification, using one standard deviation and this version using local uncertainty added.
4.3 Guide notes similar to Guide notes for Clause 4.2 added.
4.5 Explanatory notes on replacement of acronym “GPS” by “GNSS” added.
Part III – Appendices
Previous Annexures F, G and N revised to Appendices 1, 2 and 3 respectively.
Appendix 3 Bridge Diagram revised.
Ed 1/Rev 3 2.3.1 Updated due to change in Hold Point details in base specification G71
GM, IC (M Andrew)
01.10.09
Ed 2/Rev 0 Updated to accord with base Specification TfNSW G71 Ed 2 Rev 3. New guide notes and commentary added. Part III SAMPLE PROCEDURES AND APPENDICES updated to align with latest technologies and ICMS SP1 v1.7.
DCS 14.01.21
SPECIFICATION GUIDE NG71
Copyright – Transport for NSW IC-QA-NG71
VERSION FOR: DATE:
Ed 2 / Rev 0 i
CONTENTS
CLAUSE PAGE
FOREWORD ....................................................................................................................................... III TfNSW Copyright and Use of this Document .......................................................................... iii Base Specification ................................................................................................................... iii
PART I - GUIDE NOTES FOR PREPARATION OF SURVEY DOCUMENTATION ........................ 1
A GUIDE NOTES............................................................................................................................ 1 A1 Purpose of Guide Notes .............................................................................................. 1 A2 Scope of Survey ......................................................................................................... 1 A3 Prepare Procedures for Each Activity Involving Survey .............................................. 2 A4 Survey Procedures Must Be Capable of Attaining Specified Orders of Accuracy ........ 2 A5 Include Survey Checks to Verify that Survey is Correct .............................................. 3 A6 Prepare Different Procedures for Set Out and Conformity Verification ....................... 4
PART II - COMMENTARY ON CLAUSES IN SPECIFICATION G71.............................................. 1
1 GENERAL .................................................................................................................................. 1 1.1 Scope ......................................................................................................................... 1 1.2 Structure of Specification ........................................................................................... 1 1.3 Definitions and Acronyms .......................................................................................... 2
2 GENERAL SURVEY REQUIREMENTS ........................................................................................... 5 2.1 Liaison with TfNSW Director Surveying or Delegate ................................................. 5 2.2 Surveyor .................................................................................................................... 5 2.3 Quality Management System ...................................................................................... 6 2.4 Equipment .................................................................................................................. 8 2.5 Software ..................................................................................................................... 9 2.6 Records .................................................................................................................... 10 2.7 Inspection and Quality Audits................................................................................... 11 2.8 Work Health and Safety ........................................................................................... 12 2.9 Commencement of Field Survey ............................................................................... 12 2.10 Joint Surveys ............................................................................................................ 12 2.11 Care of Survey Marks............................................................................................... 13
3 SURVEY CONTROL NETWORK AND CADASTRE ........................................................................ 14 3.1 Preservation of Survey Infrastructure ........................................................................ 14 3.2 Survey Control Network ........................................................................................... 16 3.3 Survey Control Mark Register and Cadastral Mark Register ..................................... 17 3.4 Marking Land Property Boundaries .......................................................................... 18 3.5 Standards of Accuracy – Survey Control Network .................................................... 19 3.6 Control Standards of Accuracy – Construction Activities .......................................... 20 3.7 Summary of Process ................................................................................................. 22
4 SURVEY TECHNIQUES ............................................................................................................. 23 4.1 General .................................................................................................................... 23 4.2 Orders of Accuracy .................................................................................................. 23 4.3 EDM Trigonometrical Heighting Survey .................................................................. 24 4.4 EDM Tacheometry Survey ....................................................................................... 26 4.5 GNSS Survey ........................................................................................................... 27 4.6 Machine Guidance ................................................................................................... 28
Guide to G71 Construction Surveys NG71
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5 SURVEY REQUIREMENTS FOR SPECIFIC WORKS ....................................................................... 29 5.1 Earthworks ............................................................................................................... 29 5.2 Stormwater Drainage Works .................................................................................... 31 5.3 Pavement ................................................................................................................. 33 5.4 Bridges .................................................................................................................... 37 5.5 Surveys for Determining Quantities for Payment ...................................................... 48 5.6 Product Conformity Survey ...................................................................................... 48 5.7 Subsurface Utility Information (SUI)........................................................................ 50 5.8 Work-As-Executed Drawings and Model ................................................................. 51
ANNEXURE G71/A – PROJECT SPECIFIC REQUIREMENTS ................................................................... 53
ANNEXURE G71/B – MEASUREMENT AND PAYMENT......................................................................... 54
ANNEXURE G71/C – SCHEDULES OF HOLD POINTS AND IDENTIFIED RECORDS .................................. 55 C1 Schedule of Hold Points ........................................................................................... 55 C2 Schedule of Identified Records ................................................................................. 55
ANNEXURE G71/D – PLANNING DOCUMENTS.................................................................................... 56
ANNEXURES G71/F TO G71/L – (NOT USED) ..................................................................................... 57
ANNEXURE G71/M – REFERENCED DOCUMENTS ............................................................................... 58
PART III - SAMPLE PROCEDURES FOR PREPARATION OF SURVEY DOCUMENTATION AND APPENDICES ............................................................................................................... 60
SECTION A SAMPLE PROCEDURES .............................................................................................. 61 A1 Standard of Accuracy of the Survey Control Network............................................... 62 A2 Surveying Techniques .............................................................................................. 70
SECTION B APPENDICES ............................................................................................................. 75 Appendix 1 – Standard Drawing Showing Position of Batter Profiles in Relation to Design
Batter Plane.............................................................................................................. 76 Appendix 2 – Standard Drainage Drawings ............................................................................. 77 Appendix 3 – Schematic Representation of Bridge Components .............................................. 79
LAST PAGE OF THIS DOCUMENT IS ..................................................................................................... 80
Guide to G71 Construction Surveys NG71
Ed 2 / Rev 0 iii
FOREWORD
Copyright in this document belongs to Transport for NSW.
The Guide is not a contract document. It has been prepared to provide readers with guidance on the use of the specification.
The text of the base specification is shown in this Guide in shaded format.
The commentary on the intent of the specification, with guidance as to how it can be interpreted on a construction site, is shown in italic font below the specification clause to which it refers.
BASE SPECIFICATION
This document is based on Specification TfNSW G71 Edition 2 Revision 4.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
Part I - Guide Notes for Preparation of Survey Documentation
Ed 2 / Rev 0 1
PART I - GUIDE NOTES FOR PREPARATION OF SURVEY DOCUMENTATION
Part I of this Guide contains guide notes for the preparation of documentation to comply with the requirements of Specifications TfNSW Q and TfNSW G71.
A GUIDE NOTES
A1 PURPOSE OF GUIDE NOTES
The aim of these guide notes is: (a) to guide Surveyors who are engaged externally on how to set up a quality management system
for survey in accordance with TfNSW G71; (b) to create a consistent approach for surveillance of survey work on TfNSW construction projects.
Documentation for survey must be provided in accordance with TfNSW Q and TfNSW G71. The Survey Quality Plan, although written for survey, should be integrated into the PROJECT QUALITY PLAN (PQP), which will therefore encompass all work carried out on the project.
A2 SCOPE OF SURVEY
TfNSW G71 defines the scope of survey as all measurement, calculation and record procedures necessary to: (a) set out the Works;
(b) verify conformity to the Drawings and TfNSW Specifications in relation to dimensions, tolerances and three dimensional position;
(c) determine lengths, areas or volumes of materials or products, where required for measurement of work.
As defined, all surveys for conformity verification and determination of quantities require preparation of procedures for each product such as batters, pavements, kerb lines or earthworks, wherever conformity and/or quantities are specified by the Contract.
A set out is considered to be part of survey whenever it requires measurement and calculation to carry out the set out. The critical point is to determine if calculations are necessary. Where measurements for a set out can be made by other people on the project, without calculation or the use of specialised surveying equipment, and still attain the required accuracy, then that set out is not considered as part of survey.
Generally, set out which are not considered to be part of survey would be that part of the Works not having a critical spatial tolerance and is in close proximity to a verified feature, which can be either a product or a set out mark.
Example: To set out batters requires both calculation and measurement to determine the existing ground level, and it is therefore considered to be part of survey. But where the batters have been built, it is unlikely that measurements and calculations would be required to set out unlined catch drains that run parallel to the batter.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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Hence, if the catch drains are to be constructed after the batters, then as explained, the set out of them would not be considered to be part of survey. However, if required by the TfNSW Specifications, survey may be necessary to provide level control when the slope of the ground approaches 1% grade.
A3 PREPARE PROCEDURES FOR EACH ACTIVITY INVOLVING SURVEY
The procedures must cover all survey activities performed by the Contractor and/or Subcontractor applicable to survey works under the Contract.
A separate survey procedure for each survey activity provides the link between survey and quality control. Documenting the survey process provides a clear understanding of how the survey activity will comply with contract requirements.
The set out requirements of survey control the spatial requirements of the project. This role is critical to ensure that all individual components of the project integrate with each other to attain specified tolerances for position, size and shape. This will enhance quality by enabling such outcomes as:
• drainage structures that are constructed in segments joining correctly and linking with existing drainage structures or features;
• pavements surface levels that will provide the desired ride quality and design pavement thickness;
• clearing lines to minimise the amount of vegetation to be cleared;
• earthworks carried out to produce pavement of correct width with minimal waste of materials or labour;
• precast girders placed correctly in position on previously constructed bearing pads.
Survey’s role for set out is to promote quality by providing set out that is capable of delivering conformity of the products’ spatial tolerances. This should be the objective when preparing surveying set out procedures.
Conformity surveys provide verification of the spatial tolerances for payment purposes, measurements to track improvement in construction processes and records to aid the operator and maintainer of the newly constructed assets. This allows development of specifications that reflect industry standard.
Separate surveying procedures must be prepared for each individual activity rather than one generic procedure for set out and one generic procedure for conformity, due to the following reasons:
• The different Orders of Accuracy required for different construction activities requiring different surveying procedures. For example, heights for batters have a much larger tolerance than heights for pavement surface.
• Clarification of the information that is provided to construction crews for the next stage of process after the survey is completed. This includes marks placed, what is written on the marks and if any reports or diagrams are produced. This information also aids surveillance crews.
• Providing a complete record of how each process was carried out, including survey. This aids problem solving and process analysis and improvement.
A4 SURVEY PROCEDURES MUST BE CAPABLE OF ATTAINING SPECIFIED ORDERS OF ACCURACY
Survey procedures and equipment used must relate to the attainment of the spatial tolerance nominated in TfNSW Specifications.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
Part I - Guide Notes for Preparation of Survey Documentation
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Factors that will affect accuracy of traditional survey techniques include:
• equipment;
• lengths of sight lines (due to the effects of curvature, refraction, sighting accuracy, angular error of instrument);
• height of sight lines (due to the effects of refraction);
• atmospheric conditions;
• method of measuring angles;
• how many times the distance is observed, and by what method;
• conversion to the grid datum;
• nearby traffic/construction disturbances.
Procedures must adequately address the relevant factors listed above where traditional survey methods are used. If an item of work has been left out of the procedure, it cannot be assumed that the item will automatically be carried out during the survey. Hence, it should be stated in the procedure.
The amount of information provided should be appropriate to the accuracy required. Generally, for traditional survey techniques, the higher the accuracy required for the work, the more of the listed items above should be addressed.
There is no need to rigorously describe basic survey methods; competent Surveyors should know such methods. What is more important is to say when that method will be used.
Similarly, if applying atmospheric corrections, no extra explanation is necessary. The field books should show what readings were taken and the calculations show how they were applied.
A5 INCLUDE SURVEY CHECKS TO VERIFY THAT SURVEY IS CORRECT
This reflects the quality assurance (QA) philosophy of “right first time”. Checks should be included in survey procedures to assure that they have achieved the required accuracy without errors.
Survey checks should identify the following types of errors:
• systematic errors;
• errors in information such as control marks, or design information;
• human error.
Preferably, the checks should be independent of the surveying process being checked. Re-doing the same survey process as a check is discouraged and should only be used as a last resort (as too often, the same mistake is made again).
Examples of independent checks include:
• closed traverse loops;
• check shots to survey control marks;
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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• checking distances to other features whose position has been verified.
The objective is to assure that the survey is correct when completed. In this regard, an honest effort must be made to identify parts of the survey process that could produce errors and make every effort to assure against this happening.
Examples of sources of errors during the survey process include:
• measuring the heights of instruments and targets;
• transcription and reading;
• offset measurements and disturbance of the Survey Control Network.
Surveyors should describe the survey check adopted and state the tolerance for rejection of the survey. The tolerance should reflect the checking method and the required accuracy for the survey. The procedure must ensure that the survey is not used by the next stage of the process before all checks have been carried out and the survey is verified as being correct.
Information supplied by the Surveyor to construction personnel should be included in the PQP to ensure that notations on pegs, or reports, are understood. This information also assists site surveillance.
A6 PREPARE DIFFERENT PROCEDURES FOR SET OUT AND CONFORMITY VERIFICATION
This reflects the requirements of TfNSW G71 which specifies the following:
• Product conformity surveys must adopt methods that ensure independence from methods used to set out the work.
• Where possible, measurements are to be taken directly from survey control marks and not from marks used to set out the product.
• Sampling of the product for verification purposes should not be restricted to the location of points used for set out.
• Sampling is to be undertaken in a random or unbiased manner.
• The Contractor must submit a Survey Report verifying conformity for each Lot or component where design levels, position and/or tolerances have been specified.
The Drawings and TfNSW specifications must be carefully studied to determine which products need Survey Reports verifying conformity. These are generally, but not limited to, products such as pavement courses, batters, kerb lines, longitudinal and transverse drains. Information on product tolerances is usually found in TfNSW specifications for roadworks and bridgeworks.
Survey Reports verifying conformity for alignment, level and thickness are to be issued for each conforming product Lot. The Contractor must issue a Nonconformity Report (NCR) where a survey for conformity verification purposes finds that a Lot does not conform.
When nonconformity is found, a Survey Report verifying conformity can only be issued after the Principal has agreed to the disposition and the NCR closed out by the Contractor. This may be the original conformity verification survey if the Principal accepts the product “as is”. If rework is necessary, then a new survey to verify conformity is also necessary.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
Part I - Guide Notes for Preparation of Survey Documentation
Ed 2 / Rev 0 5
For pavement courses, if a construction procedure requires the Surveyor to assist in positioning of the layer during construction, or during reworking, then those observations must not be used in the Survey Report verifying conformity. A new survey must be carried out to verify conformity, independent of the construction personnel, of the whole Lot after set out is completed and the course constructed, to ensure that readings are unbiased.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
Part II – Commentary on Clauses in Specification G71
Ed 2 / Rev 0 1
PART II - COMMENTARY ON CLAUSES IN SPECIFICATION G71
TfNSW QA SPECIFICATION NG71
This Specification sets out the requirements for undertaking surveys during construction. It includes the following:
(a) Quality management system for survey work, including procedures, equipment, surveying software, records and audits, complying with Specification TfNSW Q.
(b) Maintaining the integrity of the NSW Survey Control Network and Cadastre. (c) Survey techniques for attaining the accuracies required by the tolerances specified in TfNSW
Specifications. (d) Additional survey requirements, including sampling plans for verifying spatial conformity, and
Orders of Accuracy that must be complied with to achieve tolerances contained within the various road and bridgeworks specifications.
Further guidance is provided in Specification Guide TfNSW NG71.
1.2 STRUCTURE OF SPECIFICATION
This Specification includes a series of Annexures that detail additional requirements.
1.2.1 Project Specific Requirements
Project specific details of work are shown in Annexure G71/A.
1.2.2 Measurement and Payment
The method of measurement and payment is detailed in Annexure G71/B.
1.2.3 Schedules of HOLD POINTS and Identified Records
The schedules in Annexure G71/C list the HOLD POINTS that must be observed. Refer to Specification TfNSW Q for the definition of HOLD POINT.
The records listed in Annexure G71/C are Identified Records for the purposes of TfNSW Q Annexure Q/E.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
Part II – Commentary on Clauses in Specification G71
2 Ed 2 / Rev 0
1.2.4 Planning Documents
The PROJECT QUALITY PLAN must include each of the planning documents and requirements shown in Annexure G71/D and must be implemented.
1.2.5 Referenced Documents
Unless otherwise specified, the applicable issue of a referenced document, other than a TfNSW Specification, is the issue current at the date one week before the closing date for tenders, or where no issue is current at that date, the most recent issue.
Standards, specifications and test methods are referred to in abbreviated form (e.g. AS 1234). For convenience, the full titles are given in Annexure G71/M.
1.3 DEFINITIONS AND ACRONYMS
1.3.1 Definitions
The terms “you” and “your” mean “the Contractor” and “the Contractor’s” respectively.
The terms “Surveying Act” and “Surveying Regulation” refer to the Surveying and Spatial Information Act 2002 (NSW) and the Surveying and Spatial Information Regulation 2017 (NSW) respectively.
The following definitions apply to this Specification:
Angle of inclination and declination
The angle of the line of sight above or below the horizontal, respectively.
Cadastral Reference Mark
A survey mark of the kind referred to in Schedules 3 and 4 of the Surveying Regulation.
Drawings Refer to definition in Specification TfNSW G2.
Geoid-ellipsoid separation
The distance from the surface of an ellipsoid to the surface of the geoid, measured along a line perpendicular to the ellipsoid. The geoid approximates the mean sea level.
Global Navigation Satellite System
A collection of satellite systems developed by various countries (including USA’s Global Positioning System) for navigation and positioning purposes.
Height of sight line The minimum vertical distance from a straight line to the natural surface.
Intergovernmental Committee on Surveying and Mapping
The body responsible for coordinating Commonwealth and State agencies who contribute to surveying and mapping at a national level to ensure continued cooperation and technical standards. Its role includes developing survey standards and specifications.
Line of sight A straight line joining the total station, or any other survey instrument, to the target.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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Local Uncertainty The universally accepted measure of the quality of measurement by quoting a confidence interval about derived measurements, and defined in SP1 v1.7 as “the average measure, in metres at the 95% confidence level, of the relative uncertainty of the coordinates, or height, of a point(s), with respect to the survey connections to adjacent points in the defined frame”.
In this Specification, the Orders of Accuracy for horizontal and vertical measurements are also quoted as a Local Uncertainty.
Machine Guidance System
A vehicle based system capable of providing an operator with real time feedback in relation to an electronic copy of the Design Model as reference. The system utilises sensors such as GNSS antennas, in machine and operator. It should be used only as a construction tool and not as a substitute for a survey using survey instruments such as total stations.
Model An electronic representation of the design prepared by CADD software to produce the Drawings. It also includes surface models for conformity verification and quantity surveys.
Order of Accuracy A number system for relating the spatial tolerance requirements for set out and conformity surveys to a known Local Uncertainty. Orders of Accuracy for horizontal control (coordinates) are expressed using “H” value and for vertical control (heights) are expressed using “V” value. They are not to be confused with the (Class and) Order as defined by SP1 v1.7.
Permanent Survey Mark
A survey control mark that is permanent by nature and uniquely defined by alphanumeric characters to store attributes of the mark in the records and systems of Spatial Services – Department of Finance, Services and Innovation (SS-DFSI). The marks provide the framework for all surveys to be brought onto the State Control Survey (refer Surveyor General’s Directions No. 1).
Primary Survey Control Marks
Survey marks identified on the Drawings as Primary Survey Control Marks and considered sufficiently stable and precise for construction setting out purposes. Primary Survey Control Marks are not limited to Approved Survey Marks as defined in Surveyor General’s Directions No. 1.
Resection A survey technique for determining the three dimensional coordinates of the total station set up remotely from survey control marks, by measurements to more than one survey control mark. Resection procedures must measure sufficient redundant data to enable a statistical adjustment, preferably by the least squares method that calculates residuals for each measurement.
Residual The difference between the original field measurement and the adjusted measurement when carrying out statistical adjustments, e.g. by least squares, using redundant measurements.
Sight distance The length of the sight line.
Site localisation A method of ensuring that the World Geodetic System (WGS) values supplied by GNSS are able to be related to the on-ground survey, and therefore the design.
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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Standard of Accuracy
A term used to describe the precision of survey control mark values and networks. It is a function of the equipment used, observations techniques, network design, processing and the existing control. SP1 v1.7 uses a Class and Order classification system.
Survey Control Network
The Primary Survey Control Marks plus any additional survey control marks placed to extend the Survey Control Network or to replace the Primary Survey Control Marks.
Survey Infrastructure
Permanent marks and cadastral reference marks that use as reference the New South Wales Cadastre, as defined in the Surveying Regulation. This may or may not include survey marks identified on the Drawings as Primary Survey Control Marks.
Survey mark A survey peg, bench mark, reference mark, alignment, level mark or any other mark used or intended to be used for the purpose of setting out, checking or measuring the work under the Contract.
Survey procedures Methods to control parameters that affect the accuracy of survey techniques, such as a radiation procedure or height determination procedure.
Survey techniques A survey method, such as radiation, differential levelling or tacheometry surveys.
Surveyor A responsible person nominated by, and engaged by, the Contractor to undertake the surveying role on a construction site. Surveyors must possess the Surveying qualifications and experience specified in Clause 2.2.1.
Adoption of the Surveyor General’s Directions and SP1 by G71 applies industry surveying standards and practices to TfNSW projects.
1.3.2 Acronyms
EDM Electronic distance measuring (device), i.e. total station GNSS Global Navigation Satellite System
GPS Global Positioning System
POSI Preservation of Survey Infrastructure SCIMS NSW Survey Control Information Management System
SP1 v1.7 ICSM Special Publication No. 1 Version 1.7
SS-DFSI Spatial Services – Department of Finance, Services and Innovation
SSM State Survey Mark
SUI Subsurface utility information (refer AS 5488) WGS World Geodetic System
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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2 GENERAL SURVEY REQUIREMENTS
2.1 LIAISON WITH TFNSW DIRECTOR SURVEYING OR DELEGATE
Prior to commencement of any construction activities that may affect the Survey Infrastructure (whether cadastral or state control network), contact the TfNSW Director Surveying or delegate.
Contact details for the TfNSW Director Surveying and delegates are listed in Annexure G71/E.
Liaise continually throughout the duration of the Contract with the TfNSW Director Surveying or delegate.
Where necessary, you may seek further technical advice and assistance from the TfNSW Director Surveying or delegate for the survey component of the Contract.
2.2 SURVEYOR Because of the importance that TfNSW places on survey, Clause 2.2 nominates minimum competency requirements for survey personnel who manage this work process (refer AS/NZS ISO 9001 Clause 6.2.2).
2.2.1 Qualifications
Surveyors engaged by the Contractor must hold as a minimum a Diploma in Surveying, or equivalent qualification, from a recognised tertiary institution, and have at least two (2) subsequent years of practical experience in surveying satisfactory to TfNSW.
Any assessment of equivalency in qualification to Diploma in Surveying (TAFE issued qualification) is to be carried out by survey industry organisations. TfNSW will need evidence of this assessment in order to be satisfied that this requirement has been met. Further information can be obtained from the TfNSW Director Surveying or delegate as per G71 Clause 2.1.
It is recommended that the Contractor’s Survey Manager on site holds, as a minimum, a Diploma in Surveying and has at least 5 subsequent years of practical experience.
Surveyors undertaking activities specified to be by Registered Land Surveyors must be land surveyors registered under the Surveying Act.
For surveys of Permanent Survey Marks, Bench Marks and Cadastral Reference Marks (refer Clause 3.1), comply with Section 3 of the Surveyor General’s Directions No. 11.
2.2.2 Surveying Roles and Responsibilities
Detail in the PROJECT QUALITY PLAN all construction activities requiring survey work.
List those surveying tasks and responsibilities that are assigned to Surveyors and Registered Land Surveyors.
List also the personnel who will perform survey work that is not assigned to Surveyors. Survey activities such as measurement and levelling from established survey control marks or recovery pegs, setting out profiles, etc, may be performed by appropriately trained and experienced personnel who are not qualified as Surveyors under Cl. 2.2.1, provided that a suitably qualified
(TfNSW COPYRIGHT AND USE OF THIS DOCUMENT - Refer to the Foreword after the Table of Contents)
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Surveyor verifies that the methods being used are acceptable. All activities and checks are to be documented in the PROJECT QUALITY PLAN (PQP). The PQP is to include details of any surveying activities to be undertaken by other than qualified Surveyors (e.g. installing Machine Guidance design data). The ratio of qualified Surveyors to unqualified personnel carrying out survey activities will be audited to ensure that suitable training and development is being provided. This is to ensure longevity of the profession. The responsibility for locating underground utilities is to be assigned to an accredited utility locator (refer G71 Clause 5.7 for SUI requirements). Obtaining the position and level attributes of the underground utility is to be assigned to a suitably qualified Surveyor.
2.3 QUALITY MANAGEMENT SYSTEM Contractors and their subcontractors are to verify that their work process documentation for survey control methods and equipment (see Q Clause 7.5.1) addresses the construction tolerances specified for the project, before incorporating this information in the PQP. Under Q Clause 7.4.3, contractors have the responsibility to review survey control documentation provided by their subcontract Surveyors.
2.3.1 Procedures
Provide in the PROJECT QUALITY PLAN (refer Clause 1.2.4) the procedures and equipment for carrying out the survey work, covering the measurement, calculation and recording necessary to: (a) set out the Works;
(b) verify conformity to the Drawings and TfNSW Specifications in relation to dimensions, tolerances and position in three dimensions;
(c) determine lengths, areas or volumes of materials or products where required for measurement of work.
The survey procedures must describe how the survey process is managed so that all the requirements of the Drawings and TfNSW Specifications are met. TfNSW requires contractors and subcontractors that contribute to any survey work undertaken on the site, to document the procedures that demonstrate the survey as a controlled process, for example POSI plans undertaken by a Registered Surveyor.
All surveying procedures must include checks to verify that coordinates of survey control marks shown in the Survey Control Mark Register are correct at the time of survey.
Survey procedures for verifying level conformity of pavement surfaces against design requirements in Specifications TfNSW R82 and TfNSW R83 must incorporate the requirement to use a pole with a flat base. The procedure is to include selection of survey equipment and surveying methods to achieve appropriate accuracy for specified construction tolerances. The Contractor is required to demonstrate that all work completed complies with documented procedures. Contractors need to include in the PQP a procedure for validating the model against the Drawings which should also address version control.
Provide calibration procedures for all survey equipment (refer Clause 2.4) that must be calibrated or verified.
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Provide a procedure for the records system in the PROJECT QUALITY PLAN. The procedure must include the method of storing and indexing electronic records and name all computer software used for reduction of survey measurements and calculations.
Where monitoring is required, provide as part of the PROJECT QUALITY PLAN the methodology and survey process for this. The methodology for monitoring bridgeworks and structures may also include a monitoring system to be installed at completion of the Works.
2.3.2 Management of Errors
The procedures must address all errors introduced by survey methods, including due allowance for the effects of: (a) survey equipment capability and adjustment;
(b) integrity of the Survey Control Network and Survey Infrastructure; (c) vertical refraction;
(d) grid scale factor;
(e) earth’s curvature;
(f) geoid-ellipsoid separation.
Further details of the above can be found in Surveyor General’s Directions and SP1. When using GNSS equipment, an understanding of the impact of multipath, shadowing and interference to radio frequency equipment is required.
2.3.3 Submission of PROJECT QUALITY PLAN
HOLD POINT
Submission Details: PROJECT QUALITY PLAN for survey, including:
(a) survey procedures and evidence that they are capable of achieving the specified Orders of Accuracy (refer Clauses 4 and 5);
(b) strategy for the replacement of survey control marks and cadastral reference marks (refer Clause 3.1).
Release of Hold Point: The Principal will consider the submitted documents prior to authorising the release of the Hold Point.
The PQP is to be regularly reviewed and updated by the Contractor to cover as necessary any changes in survey or construction process, new introduced survey activities or revisions required after an audit. Subsequent submissions of the PQP are to be accompanied by a detailed list of amendments to expedite Hold Point release. Details of the Surveyor undertaking “Preservation of Survey Infrastructure” are to be included in the PQP, including qualifications, instrument calibration records and survey procedures.
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2.4 EQUIPMENT
2.4.1 General
Comply with the Surveyor General’s Directions No. 5 in relation to all survey equipment used for work under the Contract.
The equipment used must be appropriate for the attainment of the tolerances nominated in this Specification.
2.4.2 Equipment Requirements
Electronic total stations and ancillary equipment used for survey tasks must have the following (or better) features: (a) electronic distance measuring device (EDM);
(b) error standard deviation of less than 5 mm ± 5 ppm for distance measurement; (c) error standard deviation of less than 3 seconds of arc for angular measurement of both
horizontal and vertical circles; (d) one second of arc minimum count;
(e) diametrical vertical circle reading and automatic tilt compensator; (f) electronically record and store field data such as horizontal and vertical angles, distances, point
notation, target and instrument heights.
2.4.3 Calibration/Verification
Carry out the calibration/verification of the electronic total station in accordance with the Surveyor General’s Directions No. 5 prior to its use for work under the Contract. Carry out similar calibration/verification after any repair, service or upgrade of firmware prior to its use.
All survey equipment used for the Contract must have a current calibration certificate, with their details recorded in the equipment register. This clause sets out the minimum calibration requirement for the total station, and highlights the requirement that all survey measuring equipment must be calibrated. This clause covers both contractor and subcontractor survey equipment, whether used long term or short term on site, including Machine Guidance systems. If unfamiliar with the above process and related terms, e.g. standard deviation, additive constant or scale factor, the TfNSW delegate may be contacted to obtain clarification. Other survey equipment requiring calibration/verification for TfNSW contracts includes: • steel tapes; • thermometers; • barometers; • levelling staffs.
All parts of the quality management system element referring to monitoring and measuring devices, as specified in Q, are to be addressed to ensure that equipment used is capable of attaining the required accuracy. Survey equipment details may be included in a dedicated Calibration Register, or in a Project Calibration Register together with other measuring and test equipment. The Calibration Register should contain the following:
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• equipment identification label; • serial number, brand name and model number; • calibration interval; • calibration date, either due date or date of last calibration; • calibration status (i.e. whether in or out of tolerance); • reference to calibration procedure.
Calibration procedures should state: • how the equipment will be calibrated (work instruction); • environmental factors to be addressed (e.g. atmospheric corrections); • acceptance criteria; • calibration interval; • actions to be taken where the equipment is found to be out of tolerance; • procedure for the removal of uncalibrated equipment. Equipment are to be labelled to identify its calibration status. Calibration settings on the equipment are to be secured. The Contractor’s Survey Manager is to ensure that the Calibration Register includes also subcontractor equipment.
2.5 SOFTWARE
2.5.1 General
The software used must:
(a) be the primary method for calculating design levels of pavement surfaces for both set out and conformity verification surveys of pavement surfaces;
(b) have the capability to determine design levels of the pavement surface at randomly selected points and make comparisons with constructed levels;
(c) have the capability of calculating design pavement surface levels with an error of less than one millimetre compared to the Drawings.
Include also the name and version of the survey software in the PROJECT QUALITY PLAN.
2.5.2 Surface Modelling Software
Where payment for earthworks under the Contract is by survey measurement of volumes, use surface modelling software that compares surveyed surfaces with previously surveyed surfaces and/or design surfaces. Include the name and version of the quantities survey software in the PROJECT QUALITY PLAN.
Where so specified, determine the thickness of a pavement course by a comparison of the conformity verification surveys of the top and bottom surfaces of the pavement course. Describe in the PROJECT QUALITY PLAN the software and process for this.
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2.5.3 Grid Coordinates to Chainages and Offsets
Where the work under the Contract requires setting out or measurements taken on pavement courses for conformity purposes, the software must be capable of converting grid Easting and Northing to chainage and offset in relation to design control lines.
2.6 RECORDS
2.6.1 General
Survey records are quality records and must be managed and stored in accordance with TfNSW Q.
Contractors are to maintain records as objective evidence to demonstrate that the survey quality management system is capable of achieving results as per the specified requirements.
The Contractor is required to establish a suitable procedure to control all records (paper and electronic) pertaining to contractor and subcontractor product realisation (such as raw data, field notes, etc) and to demonstrate conformity relating to survey activities of the Contract (refer Q Clauses 4.2.3 and 4.2.4).
2.6.2 Data in Traditional Survey Field Books
Survey data collected manually in traditional survey field books are part of the survey records. Survey field books must be clear and legible, showing the date, purpose, and location of the survey. Each survey field book must be indexed.
The Surveyor must sign all paper copies of survey field measurements, data and reductions, field books, diagrams and sketches used to set out the work, check the product for conformity or to determine quantities in accordance with TfNSW Specifications. Surveyor’s field notes are a record of field observations and are therefore part of the quality records. As such, they are to be filed and kept with other quality records. When their project work is fully complete, surveyors are to leave behind their original field notes, or a photocopy of them, on site as part of the project records.
2.6.3 Height Difference By EDM Trigonometrical Heighting
Where the surveyor radiates or determines height difference by EDM trigonometrical heighting to set out marks and uses computer software as an independent survey check, the field measurements, recorded data and resulting computer reductions will be part of the survey records. If any other survey information is produced electronically and is required to provide objective evidence that the procedure has been followed, this information should be treated in a similar manner as that for other survey records.
2.6.4 Conformity Verification Surveys
Conformity verification field book pages (whether in paper or electronic format) must be clearly labelled, dated and signed by the Surveyor with cross-indexed references to equipment used and Lot/component identification.
Where automatic data recording systems are used for verification surveys, retain a print-out or controlled electronic copy of both raw (field) data and reduced data in a similar manner as conventional field books, in addition to the electronic data.
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2.6.5 Survey Reports
At the time of survey, record the Surveyor’s name, date and signature as part of the survey data, and show these details on the survey reports (whether in paper or electronic format).
The Survey Reports generated must include references to field book page numbers.
2.6.6 Assurance
Survey records must be able to provide assurance that the surveyor has carried out all surveys in compliance with the submitted procedures, and that all surveys have attained the required accuracy.
The survey records system must be indexed for easy retrieval of information and provide a clear audit trail for all surveys.
Provide paper copies of electronically collected survey data used for set out and product conformity surveys when requested by the Principal.
2.6.7 Calibration/Verification Records
Calibration/verification records of survey equipment are part of the survey records.
2.6.8 Nonconformity Register
The surveyor must maintain (or have access to) a register of any Nonconformity Reports raised on any survey work carried out to verify conformity in accordance with the PROJECT QUALITY PLAN. Records are an important component of any quality management system. Survey records are to be included with or linked to project records to show how the process will be, or was, carried out and to verify that the survey had met the requirements. Nonconformity reporting is an important part of the improvement process as outlined in Q Clause 8.5. Survey nonconformities are to be reported in a similar manner to other nonconformities that arise on the project.
2.7 INSPECTION AND QUALITY AUDITS
2.7.1 Inspections
At any time during the duration of the Contract, the Principal may conduct inspections to verify compliance with this Specification. Cooperate with the Principal during any such inspections.
2.7.2 Quality Audits
Should field inspections and/or examination of survey records indicate that a condition adverse to quality may exist, the Principal may conduct a quality audit.
The Principal will give you at least 5 days written notice of impending quality audits.
Provide every assistance to the Principal, and persons nominated in writing by the Principal, for conduct of the quality audits.
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2.8 WORK HEALTH AND SAFETY
2.8.1 General
Comply with Specification TfNSW G22.
Provide Safe Work Method Statements for all survey activities as part of the Project WHS Management Plan.
2.8.2 Traffic Control
Provide Traffic Control Plans where required for survey activities, as part of the overall Traffic Management Plan provided in accordance with Specification TfNSW G10. Include the traffic control qualifications of surveying personnel and/or Traffic Controllers proposed.
2.9 COMMENCEMENT OF FIELD SURVEY
Prior to commencement of field survey, submit the following details to the Principal:
(a) list of surveyors proposed to undertake the survey work, including their names, qualifications and details of their experience (refer Clause 2.2);
(b) list of survey and ancillary equipment proposed for use to undertake the survey work, including unique identification, calibration and verification records in accordance with the Surveyor General’s Directions No. 5 and No. 9 (refer Clause 2.4);
(c) Safe Work Method Statements (refer Clause 2.8.1);
(d) Traffic Control Plans and traffic control qualifications (refer Clause 2.8.2);
(e) procedures for working around known heritage and other environment constraints at the Site.
HOLD POINT
Process Held: Commencement of survey field work.
Submission Details: Documents listed under Items (a) to (e) in Clause 2.9, at least 5 working days before commencement.
Release of Hold Point: The Principal will consider the submitted documents prior to authorising the release of the Hold Point.
This Clause applies to contractor and subcontractor requirements for survey activities of the contract. Details of any changes to personnel or other requirements throughout the life of the Contract are to be submitted to the Principal in a timely manner.
2.10 JOINT SURVEYS
2.10.1 General
Where so specified, or directed by the Principal, carry out a survey as a joint survey, with the Principal in attendance, unless authorised otherwise.
Provide the necessary personnel and resources to carry out, record and report the results of the survey.
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Joint surveys allow the measurement of work for payment purposes to be undertaken jointly with the Contractor and the Principal as a conformity verification survey to avoid potential differences in results. The Principal can, on a risk assessment basis, decide on its level of participation that can be as little as merely witnessing the contractor’s survey activities and reviewing results.
HOLD POINT
Process Held: Commencement of each survey specified to be a joint survey.
Submission Details: Survey date and location, surveyor’s name, description of methods and equipment to be used, at least 3 working days before commencement.
Release of Hold Point: The Principal will consider the submitted documents prior to the release of the Hold Point.
Where TfNSW specifications call for joint surveys, the Contractor is to use qualified surveying personnel. TfNSW specifications require joint surveys for bulk earthworks, pavement courses and bridgeworks. However, the Principal may at any time direct that a critical survey activity be carried out as a joint survey.
2.10.2 Submission of Joint Survey Results
Submit a report containing the results of the survey, together with relevant calculations, to the Principal within 5 working days of completion of the survey, and at least one working day before disturbing or covering up the area of the joint survey.
HOLD POINT
Process Held: Disturbing or covering up area of joint survey.
Submission Details: Survey Report, including any calculations made to determine quantities, at least one working day before disturbing or covering up area of joint survey.
Release of Hold Point: The Principal will consider the submitted documents prior to authorising the release of the Hold Point.
Joint surveys, where required for bulk earthworks, may be conducted with two independent total stations, one operated by the Principal’s surveyor and the other by the contractor’s surveyor. Under this procedure, both surveyors simultaneously sight to the same ranging pole, which is placed in various positions in order to model the surface. This method ensures that there will be agreement on the survey details taken of the natural surface. Joint surveys for other than bulk earthworks are more suitably conducted with survey methods that use two independent total stations and two ranging poles. The Principal may require access to the contractor’s survey measurements and/or computer models to resolve any survey discrepancies. When requested, this data needs to be provided in a format that is suitable for creating accurate models using the current TfNSW CADD software stated in Annexure G71/A.
2.11 CARE OF SURVEY MARKS
Preserve and maintain in their true positions all survey marks.
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Unless the disturbance or obliteration has been caused by the Principal, its employees or agents, the cost of rectification will be borne by you.
The Contractor is to take responsibility for care of the survey infrastructure and comply with requirements of Clause 3.
3 SURVEY CONTROL NETWORK AND CADASTRE
3.1 PRESERVATION OF SURVEY INFRASTRUCTURE
The Contractor is required to establish a suitable procedure to include POSI information as part of the survey records. All records pertaining to POSI and submission of information are to be readily accessible on site at all times for compliance with G71 and as objective evidence of control of the process (Q Clause 4.2.3).
The process to capture POSI information as per G71 Clauses 3.1.2, 3.1.3 and 3.1.4 are to be documented in the PQP (refer PQP requirements under G71 Clauses 2.3.1 and 2.6.1).
3.1.1 General
Comply with Surveyor General’s Directions No. 11 on, and take responsibility for preservation of the Survey Infrastructure and the treatment of Permanent Survey Marks, Bench Marks and Cadastral Reference Marks that may be affected by the Works in accordance with the Surveying Act and the Surveying Regulation. Refer also Specification TfNSW G2 Clause 42. The Surveying Act requires that a person must not remove, damage, destroy, displace, obliterate or deface any permanent survey mark or cadastral reference mark, as defined by the Act, unless authorised to do so by the Surveyor General. In addition to a maximum penalty of 25 penalty units and $2,750 per mark, as defined by the Act, a person found guilty by a court may be required to pay compensation up to $10,000 towards the cost of reinstatement plus up to $10,000 towards any loss or damage suffered.
Provide regular site induction to your workers regarding protection of Permanent Survey Marks and Cadastral Reference Marks.
3.1.2 Authorisation
Where applicable, at least 30 working days prior to the commencement of construction activities near the Survey Infrastructure, submit an application through the TfNSW Director Surveying or delegate to the Surveyor General for authorisation to remove the Permanent Survey Marks, Bench Marks and Cadastral Reference Marks that will be affected by the Works, in accordance with the Surveying Regulation. Cadastral reference marks are fundamental to the definition of the State’s property cadastre (“register of property”). The loss of these marks and permanent marks can significantly degrade the integrity and accuracy of the property cadastre and significantly add to the cost of subsequent surveys and delays to infrastructure projects.
Include with the application the following:
(a) Audit schedule (survey mark register) from a field audit of all survey marks including Permanent Survey Marks, Bench Marks and Cadastral Reference Marks within and adjoining the extent of the Works.
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The audit schedule must show the mark’s physical state (e.g. “found”, “disturbed”, “gone”), the mark’s status (type, position, height and accuracy), and date of inspection.
The schedule must also show which marks will be protected and which will be replaced.
(b) Survey Project Plan outlining the strategy and methodology for onsite mark protection and reinstatement of survey infrastructure for the duration of the Contract.
The Survey Project Plan must include a diagram or drawing showing the extent of the Works, all existing marks, proposed position and accuracy of each new mark, survey technique, and equipment to be used.
A Preservation of Survey Infrastructure (POSI) resource pack is available from the Surveyor- General’s Directions internet site at: https://www.spatial.nsw.gov.au/surveying/surveyor_generals_directions.
NOTE: POSI resource pack is a compilation of draft documents and is updated from time to time. Further information regarding POSI may be obtained by contacting the TfNSW delegate.
HOLD POINT
Process Held: Commencement of construction activities near Survey Infrastructure.
Submission Details: Application for authorisation to remove Permanent Survey Marks, Cadastral Reference Marks and Bench Marks, together with Items (a) to (b) in Clause 3.1.2, at least 30 working days prior to commencement of construction activities near Survey Infrastructure.
Release of Hold Point: The Principal and TfNSW Director Surveying or delegate will consider the submitted documents and may request further work, carry out their own site inspection and survey field measurement, prior to authorising the release of the Hold Point.
All applications for approval to the Surveyor General need to be made in consultation with TfNSW Surveying Section. TfNSW Survey Section has POSI processes in place to assist in the management of this risk.
3.1.3 Protection Measures
Implement measures to prevent disturbance of the marks which are to be preserved, and any new marks placed. If practical, place 1.5 m long stakes which are painted in a conspicuous manner around these marks, to assist in their protection or alternatively, paint around these marks.
Inform the Principal immediately if there is any unplanned destruction of parts of the Survey Infrastructure, as penalties may be imposed by the Surveyor General.
3.1.4 Removal and Replacement of Survey Marks
Notify the Principal prior to removal or destruction of survey marks that have been so authorised by the Surveyor General.
Take sufficient measurements and provide sufficient information as required to comply with the conditions under the Surveyor General’s approval to remove the survey marks. The conditions may include placement of new permanent marks and lodging of a Deposited Plan of Survey Information
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Only (DPOSIO) during and post construction period. The DPOSIO work must be undertaken by a Registered Land Surveyor. The Contractor is to provide evidence of compliance with all conditions of approval to destroy or disturb marks. This may require the necessary observations to be taken to enable compliance with POSI strategy and obtaining the Surveyor General’s approval as per G71 Clause 3.1.4 Hold Point.
Refer to the Surveying Regulation and the Surveyor General’s Directions No. 11 and No. 12.
The local TfNSW Survey Manager is available to provide advice on compliance with this Clause and Surveyor General’s Directions No. 11 and No. 12; however obtaining the Surveyor General’s approval verifying compliance with this Clause may require more time than the minimum 2 days specified in the Hold Point.
HOLD POINT
Process Held: Any activities that may cause removal, damage, destruction, or obliteration of a permanent control or cadastral mark.
Submission Details: Surveyor General’s approval under the Surveying Regulation, at least 2 days before disturbing the mark.
Release of Hold Point: The Principal will consider the submitted approval and any conditions and may inspect the site, prior to authorising the release of the Hold Point.
3.2 SURVEY CONTROL NETWORK
3.2.1 General
The Principal will provide you with the Primary Survey Control Marks and information necessary for setting out the Works.
Take responsibility for these marks and any additional marks that form the Survey Control Network and verify their integrity before commencing any survey activity.
The Survey Control Network defines the accuracy of all survey work carried out on the project and hence the spatial accuracy of the final product.
The Drawings and Survey Control Mark Register contain the Primary Survey Control Marks that are suitable and sufficient for setting out the works. These marks may include survey control marks that form part of the State Control Survey and additional stable marks placed for the project. The Primary Survey Control Marks, plus additional survey marks placed during construction form the Survey Control Network, as outlined in Clause 1.3.1 Definitions.
HOLD POINT
Process Held: Use of survey control marks forming part of the Survey Control Network.
Submission Details: Survey Report verifying coordinates and level values of the survey control marks, at least 10 working days before use of the marks. Where requested, submit the procedure for replacing the affected Primary Survey Control Marks.
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Release of Hold Point: The Principal will consider the submitted documents and may inspect the marks prior to authorising the release of the Hold Point.
The responsibility for verifying coordinates of the survey control marks lies with the Contractor. While TfNSW has ensured that all care was taken in placing and coordinating the Primary Survey Control Marks, it is not possible to guarantee that they will not be disturbed prior to their use for construction activities. This Hold Point is to ensure that the Contractor verifies the supplied coordinates of the survey control marks before using them.
Verification of coordinate values of the Primary Survey Control Marks is good survey practice and should therefore be included as part of the Contractor’s survey cost.
3.2.2 Protection Measures
Implement measures to prevent disturbance of the survey control marks defining the Survey Control Network. If practical, place 1.5 m long stakes which are painted in a conspicuous manner around the survey control marks to assist in their protection or alternatively, paint around these marks.
3.2.3 Placing Additional Survey Control Marks
Where additional survey control marks are required to break down the Survey Control Network, position such marks with due regard to maximising their use and protection against disturbance by construction activities. This includes placing survey marks that are substantially stable.
Where a survey control mark is affected by the execution of works, establish other stable marks of the same standard of accuracy that are clear of the Works prior to the commencement of work in the affected area.
All survey control marks placed are to be suitably identified in the field as per the Survey Control Register. All marks are to be placed clear of potential utility strikes.
3.2.4 Survey Control Network At Completion
Ensure that at Completion, a Survey Control Network of similar integrity as the one shown on the Drawings, including distribution and standard of accuracy, is in place.
Comply with Surveyor General’s Directions No. 11 and No. 12 when ensuring the integrity of the final State Survey Control Network. The Surveyor General’s Directions contain requirements for mark placement, network design, computation/adjustment, the Survey Report and special requirements relating to the use of GNSS techniques. The TfNSW Director Surveying or delegate can provide assistance with compliance to ensure the integrity of the Survey Control Network.
3.3 SURVEY CONTROL MARK REGISTER AND CADASTRAL MARK REGISTER
3.3.1 General
Maintain a current Survey Control Mark Register and Cadastral Mark Register of all survey marks.
Include the schedule from the field audit of survey marks (refer Clause 3.1.2) in the mark registers.
The register forms part of the quality records and must be controlled in accordance with your Quality Management System. Retain superseded copies of the register.
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Provide the Principal with an updated copy of the register whenever the register is updated.
3.3.2 Survey Control Mark Register The Survey Control Mark Register assists in site surveillance by ensuring that all surveillance surveys work from the same datum as that of the Contractor’s Surveyor. Disturbance of existing survey control marks or the addition of extra survey control marks will require updating the Register. An example for control and cadastral marks is in the POSI resource pack. This is pre-design and does not include chainage and offset details.
Include the following information, where practicable, in the Survey Control Mark Register:
(a) a unique number/identifier for each survey control mark; (b) any other identifier such as an SSM number;
(c) Easting, Northing and Height of each survey control mark, except for marks used for reference sightings only;
(d) chainage and offset of each survey control mark in relation to a main control line, where it is practical to do so and where a main control line exists;
Where a project is a complex interchange with several design control lines, and those control lines do not have simple geometric relationships with each other such as being parallel, it may be impractical to provide chainage and offset to a control line. However, where a main control line exists, such as for freeway or arterial road construction, the provision of chainage and offset of survey control marks to such a design control line would greatly assist in locating the survey control marks. (e) description of the physical nature of each survey control mark, such as star picket or pre-drilled
concrete nail. The survey control mark description assists in locating marks in the field.
3.3.3 Cadastral Mark Register
Include the following information, where practicable, in the Cadastral Mark Register:
(a) a unique number/identifier for each cadastral (reference) mark;
(b) any other identifier such as an SSM number; (c) Easting, Northing and Height (where applicable) of each cadastral mark;
(d) description of the physical nature of each cadastral mark, such as peg or drill hole;
(e) Deposited Plan number;
(f) status (e.g. “Gone”, “Not found”, “Found”);
(g) project impact (e.g. “Safe”, “Vulnerable”, “To be destroyed”); (h) date when reported to SS-DFSI.
3.4 MARKING LAND PROPERTY BOUNDARIES
Where the Drawings or Design Model indicate that construction work will be carried out within 300 mm of a property boundary, determine the actual property line using the most current cadastral information supplied by the NSW Land Registry Services.
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This must include a survey carried out by or under the direct supervision of a Registered Land Surveyor, in accordance with the Surveying Act. In accordance with the Surveying and Spatial Information Act and Regulation, a Registered Land Surveyor is the only person authorised to mark property boundaries in NSW.
Do not use the cadastral electronic model (or overlay), or the Digital Cadastral Database to define the property boundaries. The 300 mm offset distance is for well-defined urban areas. Where the cadastre is in doubt and/or in rural areas, the offset distance may be increased. Advice should be obtained from the TfNSW Director Surveying or delegate.
3.5 STANDARDS OF ACCURACY – SURVEY CONTROL NETWORK
When verifying, extending or breaking down the Survey Control Network, three Standards of Accuracy are applicable for the procedures, depending on the survey activity, as shown in Table G71.1. This Clause includes Standards of Accuracy using GNSS techniques as well as traditional survey methods. However, the Classes define a Standard of Accuracy and not survey methods; therefore this Clause does not restrict the use of developing technology, where its capability can be verified.
Table G71.1 – Standards of Accuracy for Survey Control Network (1)
Activity Horizontal Control Vertical Control
Traditional Survey Methods
GNSS Techniques
Differential Levelling
Trigonometrical Levelling
GNSS Techniques
Bulk Earthworks Class E Class C Class LE Class D Class C General Construction Activities Class C Class B Class LC Class B N.A. Specialised Construction Activities LU 4 mm N.A. Class LA N.A. N.A.
Note: LU = Local Uncertainty N.A. = Not applicable (1) Classes listed in Table G71.1 are in accordance with the NSW Survey Control Information Management System (SCIMS). Refer to
Surveyor General’s Directions No. 12 and SP1 v1.7.
The Class of a control survey, as stated in SP1, is based on, amongst other things, the survey field methods, reduction techniques, redundancies and network design (direct connections between marks) adopted. Class C horizontal control for General Construction Activities is based on good survey practices adopted by Surveyors when carrying out normal control surveys, including control for survey investigation and cadastral control surveys.
For Specialised Construction Activities, a higher precision than Class C is required. Class B control surveys by SP1 has a more precise determination as a proportion of length of lines than a Class C control. However, the precision of each survey control mark may not be better than a Class C control survey with shorter lines and therefore may not be acceptable for some TfNSW works. Adoption of survey techniques described in SP1 for Class B survey control is not applicable to TfNSW construction projects due to the shorter lines on TfNSW projects.
Use survey methods that will achieve the specified Classes for each Standard of Accuracy.
Clause A1 in Part III of this Guide contains the procedures referenced in G71 for verifying, extending or breaking down the Survey Control Network. The procedures listed in Clause A1 are not mandatory but if they are not used, the Contractor must submit details of alternate procedures to the Principal for approval before using these alternative procedures.
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Provide evidence that the Local Uncertainty (refer Clause 1.3.1 for definition) for survey control developed for Specialised Construction Activities is no more than that shown in Table G71.1. To ensure the precision of each survey control mark, LU is adopted for the acceptance criteria for the control for Specialised Construction Activities. Adoption of LU gives greater confidence in the absolute precision of each survey control mark. The magnitude of the LU in Table G71.1 is based on the spatial tolerances contained in TfNSW Specifications that require more precise control, e.g. some TfNSW bridgeworks specifications. Clause A1.3.1 in Part III of this Guide has a procedure to achieve LU 4 mm; this procedure may be adopted as the process for the Contract. If the survey process differs from this procedure, the survey process to be undertaken is to be included as a separate procedure in the PQP.
3.6 CONTROL STANDARDS OF ACCURACY – CONSTRUCTION ACTIVITIES
3.6.1 General
Use surveying procedures with accuracies that are commensurate with those of the construction activities stated under Clauses 3.6.2 to 3.6.5.
Survey control marks of a lower Standard of Accuracy may be appropriate on some occasions. Conversely, survey control marks with a higher Standard of Accuracy may be necessary for some specialised surveys, as outlined below.
Refer to Clause 3.5 for requirements.
Document the survey processes in the PROJECT QUALITY PLAN.
3.6.2 Control for Bulk Earthworks
Construction activities where survey control marks forming the Earthworks Control may be used include determination of bulk earthworks quantities, determination of the extent for clearing and grubbing, and initial set out of the earthworks.
When placing or verifying survey control marks for bulk earthworks, you may use survey procedures with a lower Standard of Accuracy than that required for General Construction Activities. Refer to Table G71.1.
The local uncertainty of the coordinates of the marks of the Earthworks Control must be less than one- third of the tolerance of the survey for which they will be used. Refer to Clause 5.1.2 for Orders of Accuracy for set out and conformity verification.
Do not include the Earthworks Control in the Survey Control Marks Register (refer Clause 3.3). All survey marks placed for the Earthworks Control are to have survey check measurements to established survey control marks or coordinated features. No adjustment to survey measurements is required for atmospheric conditions, including refraction or conversion to the grid datum.
3.6.3 Control for General Construction Activities
General Construction Activities cover most of the work under the Contract, and include the following: (a) final earthworks surfaces immediately below pavement courses;
(b) pavement courses;
(c) drainage structures;
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(d) other structures on top of pavement courses, such as kerbs;
(e) road furniture;
(f) some bridgeworks and other concrete structures (refer also Clause 3.6.4).
Do not use the Earthworks Control for General Construction Activities. Generally, all survey work carried out on TfNSW projects will use a Survey Control Network with coordinates determined to the accuracy specified for the General Construction Activities Control.
As soon as practical, place and survey all survey control marks to the Standard of Accuracy required for General Construction Activities. Distinguish using different markings those marks that have accuracy suitable for General Construction Activities from those marks suitable for Earthworks Control.
Verify that the Primary Survey Control Network is suitable for General Construction Activities (refer Clause 3.2).
Coordinates of the Primary Survey Control Network issued with the Drawings are surveyed to accuracy suitable for General Construction Activities. The Contractor is to validate the survey control values and may place additional marks as part of activity associated with Clause 3.2.1 Hold Point. In order to expedite the initial start-up phase of the project, some earthworks and clearing activities may use survey methods of a lower Order of Accuracy than that for General Construction Activities. However, the Contractor will still require procedures to ensure that the process is suitably controlled and does not introduce gross errors.
3.6.4 Control for Specialised Construction Activities
The Principal may direct you to carry out survey work to a higher Standard of Accuracy than that which is possible using survey control marks coordinated to an accuracy suitable only for General Construction Activities. Refer to Table G71.1 and Clause 4.2 for Orders of Accuracy.
This will apply to some bridgeworks, monitoring or specialised surveys.
Procedures are required to ensure that the process is controlled for Specialised Construction Activities. Some TfNSW bridgeworks specifications, such as incrementally launched bridges, specify a higher Order of Accuracy than that which is achievable using survey control marks measured to an accuracy suitable for the General Construction Activities Control.
3.6.5 Control for Bridgeworks
Where you establish a control for General Construction Activities or Specialised Construction Activities specifically for bridgeworks, use ground distances in place of grid distances for all lines when calculating coordinates of the survey control marks (refer also Clause 5.4.1). While TfNSW road design is usually based on grid distances, bridges and structures are usually designed using ground distances. The difference varies around NSW and can be as high as 700 ppm (or 0.7 m per kilometre). The Contractor’s Surveyor needs to fully appreciate this and develop Bridge/Structures Control on a local assumed datum for these circumstances. The methodology must include calculations and adjustment and be included in the PQP.
Grid distance = ground distance x combined scale factor (CSF) Specialised construction may include tunnels, noise walls and other structures. Further information may be obtained from the TfNSW Director Surveying or delegate.
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Further details for the Bridge Control are contained in Clause 5.4.
3.7 SUMMARY OF PROCESS
A summary of the process for developing, maintaining and extending the Survey Control Network is shown in Table G71.2.
Table G71.2 - Developing, Maintaining and Extending the Survey Control Network
Time Line Actions by Contractor Details Outcome Start of Contract Receive from the Principal the
Primary Survey Control Marks.
Sufficient survey control marks to set out the Works
Identify and preserve/recover Permanent Survey Marks and Cadastral Reference Marks likely to be affected by the Works.
These marks are part of the Survey Infrastructure as described in Surveyor General’s Directions No. 11. Contact TfNSW Director Surveying, or delegate. Submit an application through TfNSW Director Surveying or delegate to the Surveyor General for authorisation to disturb the marks. Work involving Cadastral Reference Marks must be done by a Registered Land Surveyor. HOLD POINT on commencement of construction activities in affected area applies.
Collection of sufficient measurements and actions taken for the preservation of the NSW Survey Infrastructure. Survey information for preservation of cadastral survey marks verified and HOLD POINT released.
Protect the Primary Survey Control Marks from construction activities.
Place stakes, markers or other means to highlight location of survey control marks for their protection.
Survey control marks protected to assist construction activities.
Verify coordinates of the Primary Survey Control Marks before use.
HOLD POINT on use of the Survey Control Network applies.
Survey control marks verified and HOLD POINT released.
Clearing and grubbing and initial bulk earthworks activities
Initial break down of the Primary Survey Control Marks to form the Survey Control Network.
May use Earthworks Control procedures for these construction activities. Use different marking notation for Earthworks Control.
Initial construction activities are expedited by using survey control applicable to the Works.
Completion of bulk earthworks and initial pavement construction commences.
Continue to break down the Survey Control Network. Ongoing monitoring of survey control marks.
All survey control marks placed for the Earthworks Control are now surveyed for use in General Construction Activities.
The Survey Control Network becomes suitable for General Construction Activities.
Specialised Construction Activities.
Break down the Survey Control Network using higher order procedures.
Use procedures relating to Specialised Construction Activities to place extra survey marks or survey existing marks.
Tolerances stated in bridge specifications or as directed for specialised surveys can be achieved.
Contract completion Provide the Principal with Survey Control Network of similar integrity of the Primary Survey Control Marks.
Replace survey control marks destroyed during construction of the Works in safe positions, if it was not possible to do so during construction.
The Primary Survey Control Marks are available for future TfNSW works.
Close out outstanding actions for compliance with Surveyor General’s Directions No. 11 and No. 12. Comply with all conditions of Removal of Survey Marks approval from SS-DFSI.
Replace destroyed permanent marks in safe positions, if it was not possible to do so during construction. Prepare and submit plans, locality sketches, data and diagrams as required by Surveyor General’s Directions No. 11 and No 12.
The NSW Survey Infrastructure is preserved to assist future capital works programs and the Cadastre is protected.
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Table G71.2 is a flowchart of the processes for receiving, verifying, extending, breaking down and protection of the Survey Control Network from start to finish of the project for compliance with Clause 3.
4 SURVEY TECHNIQUES
4.1 GENERAL
Comply with the Orders of Accuracy for horizontal control (coordinates) and vertical control (heights) checks for the construction activities listed in Clause 5 to satisfy spatial requirements. The Orders of Accuracy listed in Clause 5 use the notation contained in Clause 4. Procedures are to attain the Orders of Accuracy specified in Clause 5 regardless of the survey technique adopted. Orders of Accuracy are not to be confused with “Standards of Accuracy” in survey control.
Orders of Accuracy refer to the spatial tolerance requirements for ensuring that set out and conformity survey processes are fit for purpose. While set out and conformity surveys require checking and validation systems for survey radiation methods, survey control relies on network interconnectivity and redundancy.
Use the surveying procedures in Guide TfNSW NG71 for traditional survey methods of