The importance of survey within design & construction Presented by Alex Martinov, TrackRight Consulting

Is this a No-Brainer ?

• The topic name sounds like a no-brainer to any Surveyor, but it is important to clearly explain / educate / inform Project Managers and Engineers on survey best practice methods and how these will benefit their project

• Based on my experience, most Project Managers & Engineers do not have a clear understanding of what expertise a Surveyor can bring to a project and how to exploit this knowledge

• The survey will provide one Co-Ordinated spatial referencing system for the lifetime of the project. It will embrace all the survey work required for engineering design, pre-construction early works, construction setting out and provision of “As-Built “ data and future maintenance

• When given an opportunity, the Surveyor must have a comprehensive understanding of what the project involves, and then must optimise the required surveying services from project start to finish

• The Surveyor must emphasise / sell the importance of establishing appropriate survey requirements for each Design & Construction project, as it is not ‘one size fits all’, as most Project Managers and Engineers believe

• Emphasise the need for a coordinated approach • Aerial mapping by Lidar combined with ortho-rectified photography • Importance of a cadastral survey, and a lessons learnt example • Services and Utility surveys, and a lessons learnt example • Interface with GIS

The purpose of an Engineering Survey

consists of:

• CONTROL NETWORK – provides a spatial 3D coordinate grid system

• TOPOGRAPHIC & INFRASTRUCTURE DETAIL SURVEY – localised capture of all natural & man-made features for investigation and design purposes

• CADASTRAL SURVEY – establishes position of relevant legal property boundaries and existence of easements, leases or any other encumbrances

• SERVICES & UTILITIES SURVEY – establishes the existence and location of above and below ground services within and near the project’s perimeter area

• Often the client will need educating on the requirements needed!

MGA ZONE WIDTH BOUNDARIES

Topographic and Infrastructure Detail Surveying

• Every project site will have a unique mix of existing natural and manmade features which require survey data capture

• Small sites are usually covered by ground-based survey, but not alwaysdue to project site

• For very large sites data capture by LIDAR and Ortho-rectified aerial photography will provide time and cost benefits compared to ground survey

• If survey information is provided by the client an independentverification / audit would be advised to mitigate data conflict mid design

Aerial mapping by Lidar combined with ortho-rectified photography

• Considerable time and cost benefits compared to conventional ground survey, but can be significantly less accurate

• Requesting higher accuracy and resolution deliverables by aerial methods will significantly raise the costs

• Lidar unable to determine water depth, culvert and pipe inverts, etc. so additional ground survey must be factored in. Pooling of water during heavy rain periods will distort surface model / earthwork design

• Ground survey is still required to accurately locate existing structural infrastructure

• TRUTHING BY GROUND SURVEY MUST BE CARRIED OUT TO MITIGATE ERRORS IN AERIAL MODEL DATA (do not blindly accept)

• IF SURVEY INFORMATION IS PROVIDED BY THE CLIENT, AN INDEPENDENT VERIFICATION / AUDIT WOULD BE ADVISED ESPECIALLY IF THE CLIENT WANTS A THIRD PARTY TO TAKE OWNERSHIP OF DATA SUPPLIED

Benefits of a Cadastral survey

Area between Bd’y & Fence has potential for infrastructure encroachment

Excess land now available for use

Sketch of proposed conveyor plant layout

Proposed survey scope & amended scope End poi n t

Services & Utility Surveys (use in design)

Potholed location differs from scanned location by approx.1.5m

Services & Utilities bottom line

• To mitigate risk all critical services must be located by direct exposure this is cost and time intensive, NO CUTTING CORNERS

• All bends and junctions must be spatially located

• Hold points in program must be placed for survey team to locate accurately, before cover up