Evelina London Children’s Hospital

Measured Building Survey

• Floor Layout Plans
• Elevations
• Cross Sections
• Roof Layout Plan

Sector: Commercial Property

About This Project

SurveyWorx were commissioned to manage & deliver the Survey Specification, working in collaboration with the Architectural & Structural Design Teams who would lead the redevelopment across the Project.

Evelina London Children’s Hospital is a specialist NHS Hospital in Westminster Road, London. It is administratively a part of Guy’s and St Thomas’ NHS Foundation Trust and provides teaching hospital facilities for London South Bank University and King’s College London School of Medicine.

Using a combination of the latest integrated Robotic Total Stations, GNSS, HD Laser Scanning Technology & “Robust Survey Methods” to capture & verify accurate Survey Data, the full Survey Specification was delivered both efficiently & cost effectively within the allocated timescales.

Establish Control Network Framework

Primary Survey Control was established using Total Station, GNSS & Precise Levelling. PK/Mag Survey Nails with Survey Markers were drilled/fixed into hard standing surfaces with Station Description Sheets completed to aid with follow-on Construction/Engineering Works. Secondary Control was transferred by Total Station from Primary Control Stations through the main corridors/reception areas through door/window openings & closed on Primary Control Stations with additional Verification/Checks completed on to Primary Stations where visible. Black & White Laser Scanning Targets (Checkerboard Targets) were positioned at key locations throughout the Building/Property & observed as Tertiary Control to reference Laser Scanning Works.

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.

Scan Data Post-Processing

Over 325 Scans were captured & Post-Processed to produce a fully Registered/Coordinated Point Cloud, using Leica Cyclone Software. Point Cloud Data was referenced to Site Control Network using Tertiary Control Coordinates observed from Secondary Control within the Building. Post-Processing/Registration was completed using a combination of Target-Based Registration & Cloud-to-Cloud 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.

Survey Data related to the OS Network OSGB36(15).

The final Drawing Package included; Topographical Survey, Floor Plans, Elevations, Cross Sections & Roof Plan. All Drawings were passed through Quality Assurance prior to final delivery.

All work will be produced in accordance with the RICS Specification: Measured Surveys of Land, Buildings & Utilities – 3rd Edition.

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.