Barrel Arch Bridge

• Monitoring Consultancy
• Establish / Verify Site Control
• HD 3D Laser Scanning
• Total Station & 3D Monitoring Targets
• Automated Real-Time Tilt Sensors
  

Sector: Infrastructure & Engineering

About This Project

SurveyWorx were commissioned to manage & deliver the Structural / Movement Monitoring Specification, working in collaboration with the Structural Engineering Teams across the Project. Monitoring Data would provide the Structural Engineering Team with critical information in Real-Time relating to the Structures behaviour during the Project.

Control Network Framework

Primary Survey Control Stations were located on Site & Verification/Checks were completed utilising a combination of GNSS, Robotic Total Station (1”) & Precise Levelling Techniques. Primary Control was Adjusted & additional Survey Stations were included to determine optimum Network Geometry & ensure adequate Redundancy was present within the Control Network Framework.

Permanent PK/Mag Survey Nails & Survey Markers were drilled/fixed into hard standing surfaces. Photographic Documentation of Survey Stations was captured with Station Descriptions Sheets completed for issue to Client.

Survey Methods & Data Acquisition/Capture

Using a combination of the latest integrated HD 3D Laser Scanning Technology, Total Stations & Automated Structural Monitoring Tilt Sensors, Monitoring Data was Captured/Recorded across the Project. Real-Time Sensors were installed on the Bridge/Structure, with Real-Time Data captured at 1 Minute Intervals with Monitoring Data presented both Graphically & Numerically.

HD 3D Laser Scanning & Heat Mapping

HD 3D Terrestrial Laser Scanning Techniques were deployed to complete the Structural Movement Monitoring at Weekly Intervals. Point Cloud Data was compared against Baseline Data to analyse and determine Movement/Settlement across the Bridge/Structure.

Data Post-Processing & Presentation

Data was Post-Processed, Analysed & Presented as Heat Maps displayed as a Traffic Light System (Green, Amber & Red) based on agreed Trigger Levels & associated Action Protocols.

Action Protocols & Trigger Levels

• Green <5mm (Maintain Monitoring Regime)
• Amber 5-9 (Review & Report to Consultant Structural Engineers)
• Red ≥10mm (Review & Investigation by the Consultant Structural Engineers)

Total Stations & 3D Monitoring Targets

24 No. 3D Monitoring Prisms/Targets (X,Y,Z) were permanently fixed to the Bridge/Structure with Readings/Observations taken at Weekly Intervals across the Project. Data was presented both Graphically & Numerically as changes to Eastings (Lateral Movements), Northings (Longitudinal Movements) & Elevation (Height Movement), typically to within +/- 1mm.

Data would be analysed & presented in a Traffic Light System (Green, Amber & Red) based on agreed Trigger Levels & associated Action Protocols.

The resulting Data provided critical indicators to predict possible issues relating to potential Settlement or Collapse.

Tilt Sensor Solution AUTOMATED

Real-Time Tilt Sensors were installed on the Bridge/Structure, with Data captured at 1 Minute Intervals & sent Automatically to a 3G/4G GateWay.

Action Protocols & Trigger Levels

• Automated Real-Time Tilt Sensors
• 12 No. Tri-Axial Tilt Sensor Nodes

Web-Based Processing & Presentation

Data was sent Automatically to a 3G/4G GateWay pushing data to the Monitoring Software Suite; a Web Interface to display the Data On-Line, to View & Download.

• Automated Notifications when Trigger Levels/Limits are breached/exceeded
• Access Real-Time Live Data via Web-Based Platform
• Download a CSV file directly from the Web Interface
• Email & SMS Notifications/Alerts

Data would be analysed & presented in a Traffic Light System (Green, Amber & Red) based on agreed Trigger Levels & associated Action Protocols.

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

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).