As-Built Construction Verification
- As-Built Surveys
- Construction Verification Reports
- HD 3D Laser Scanning
Sector: Construction & Engineering
About This Project
SurveyWorx were commissioned to manage & deliver the Survey & Engineering Specification, working in collaboration with the Construction & Design Teams who would lead the Construction/Development of the Project.
Deliverables/Outputs would highlight deviations between the As-Built Constructed Position & Design.
As-Built Drawings would be delivered to tight a programme/timeline to comply with our Contract on the Project. Accurate Survey Data/Drawings would provide Project Managers & Design Teams with vital information in relation to the true positional accuracy of constructed elements when compared against the Design Drawings.
The Greenwich Peninsula Project is a mixed-use development in North Greenwich, London, comprising over 500 Apartments/Homes across 7 RC Frame High-Rise Buildings/Structures, ranging from 12 to 26 Floors/Levels.
As-Built Survey Specifications
- Establish/Verify Control Network
- Slab Level Verification (+/- SSL)
- Slab Edge Position
- Columns – Position & Verticality
- Slab Openings/Penetrations
- Structural Beams Position & Level
- Lift Shaft Position & Verticality
- Construction Verification Reports
Survey Methodology & Project Delivery
As-Built Survey Data was captured/acquired using Total Stations (1“) & Leica P40 HD Laser Scanners.
Establish Control Network Framework
Primary Control Network & Grid System was Verified/Checked using a combination of Total Station (1“), Zenith/Vertical Laser Plummet, Steel Tape & Leica Precise Digital Level (DNA03)
Survey Control Network Post-Processing
Field Observations were Post-Processed through MicroSurvey’s STAR*NET Software to calculate Least Squares Adjustment & Analysis (Residuals, Standard Errors, Error Ellipses) to produce final Control Network Coordinates.
Data Acquisition/Capture
Data was acquired/captured using a combination of HD Laser Scanning Technology, Robotic Total Stations & Hand-Held Tablets. HD Scan Data was captured with significant overlaps between individual Scans to ensure high quality referenced data was acquired.
HD Scan Data Post-Processing
HD Scan Data was Post-Processed to produce a fully Registered/Coordinated Point Cloud, using Leica Cyclone Software. Point Cloud Data was referenced to the Site Control Network using Secondary Control transferred vertically through the Buildings/Structures using a Zenith/Vertical Laser Plummet. Post-Processing/Registration was completed using a combination of Target-Based Registration & Cloud-to-Cloud Registration.
Quality Assurance procedures were completed with a Point Cloud Registration Report exported to highlight registration accuracy. Registration was a success with an average error of +/-2mm between individual Point Clouds.
The Point Cloud was Verified/Checked by taking sample Cross Sections/Slices through the Data in order to check for any discrepancies between individual Point Cloud alignments. Point Cloud Data from the Internals was also Verified/Checked against the External Data to confirm successful Registration.
Quality Assurance (QA/QC)
Quality Assurance procedures were completed with a Point Cloud Registration Report exported to highlight registration accuracy. Registration was a success with an average error of +/-2mm between individual Point Clouds.
The Point Cloud was Verified/Checked by taking sample Cross Sections/Slices through the Data in order to check for any discrepancies between individual Point Cloud alignments. Point Cloud Data from the Internals was also Verified/Checked against the External Data to confirm successful Registration.
Coordinate Reference System
Delivery & Output
Drawings were delivered in defined categories to aid Design Teams by providing accurate & concise information while avoiding cluttered/crowded Drawings. 1) Vertical Elements; Columns, Walls & Cores. 2) Structural Slab Levels; Floor/Slab Flatness. 3) Structural Openings & Formed Edges; Slab Edge; Openings/Penetrations & Balcony Bracket Halfen Channels.
The final Drawing Package included; As-Built Survey Drawings (approximately 375 drawings issued) & Control Network Reports. All Drawings were passed through Quality Assurance prior to final delivery.
The completed Surveys were delivered as a digital version in 2D AutoCAD & PDF formats.
Glossary
GNSS = Global Navigation Satellite Systems.
RTK = Real Time Kinematic.
GPS = Global Positioning System.
OSGB36 = Ordnance Survey National Grid Reference System.
ETRS89 = European Terrestrial Reference System.
WGS84 = World Geodetic System (GPS/GNSS).
ITM = Irish Transverse Mercator.
Sample Delivery/Output
Services
