Asset Management using Digital Image Correlation Jan Winkler PhD

Chief Specialist, Team Leader, TransportationMob: +45 52519027Email: jan.winkler@atkinsglobal.com

Rail and Transit

Ports and Marine

Oil and Gas

GeneralInfrastructure

Buildings and Facilities

Highways andBridges

Customer Benefits and Key Features

Benefits to the Customer

› DIC allows for massive savings of public funds by extending the service life of infrastructure

› Avoid possessions, lane closures and working at height or in confined spaces

› Avoid unnecessary and costly strengthening

› Allow clients to keep bridges open for longer and maintain un-hindered traffic flow

› Extend the working life of a bridge and get more transport service for that carbon footprint.

› Optimise the use of transportation infrastructure via DIC

› Cost effective and easy-to-collect objective measure of asset performance

Key Features

› Accurate, inexpensive, easy to interpret

› High precision: 0,1 mm from 100 m + strain/stress (up to 1-3 MPa)

› Non-contact = no traffic disruption, no rail and highway possessions

› Multipurpose tool: Strain/stress, rotation, displacement measuremements using 1 camera

› Long term & short term monitoring

› Scale and material independent solution (steel, concrete, timber)

› Fast data acquisition: 1-100Hz

› Atkins DIC capability (in-house algorithms, equipment, team of specialist)

› Quick FE model validation (e.g. SLS / ULS)

› A cutting-edge camera-based technology

Market SectorsInformed decisions on timely intervention for effective asset management activities rely on good quality, accurate and reliable monitoring data. Digital Image Correlation (DIC) is a contactless measurement technique, for determining deflections and strains in structures without the need for surface contact or rail and highway possessions.

DIC can be used for either monitoring over time, by imaging a structure periodically and analysing changes in behaviour, or for assessing snapshot behaviour where there are particular concerns about a way a structure is performing. The former facilitates tracking the deterioration history of a defect and informing its cause and a suitable intervention; the latter helps assess if there is an immediate need for intervention.

Asset Management using Digital Image Correlation

Technology Comparison DIC Strain gauge, LVDT, Fiber optic gauge

Contactless (no traffic disruption) Yes No

Precision few µε / sub mm few µε / sub mm

Multi-purpose sensor (4 in 1)(strain,displacement,rotation,acceleration)

Yes No

Full-field strain map (mm2 – m2) Yes No

Multi-point measurement Yes No / Yes

High Speed & Real time Yes Yes

Short & Long term monitoring Yes Yes

Set-up time 30 min few hours/few days

Day & night measurements Yes Yes

Experts in vision-based structural monitoring

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Bearing, Half Joint, Expansion Joint Applications Superstructure, Deck, Dynamic Applications

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Monitoring challenge: Dynamic monitoring of the bearing movement to exclude the possibility of uplift.

DIC methodology: A single camera system with lens selection providing live results on bearing movement due to traffic.

Value added: Measurement carried out without the need for rail and road closures. Night works and working at height were avoided. All setting up, data capture and packing away was completed within a few hours.

Gade Valley Viaduct(Client: Connect Plus)

French Horn Bridge(Client: Wiltshire Council)

Monitoring challenge: Dynamic monitoring of the bearing rotation and deck displacement with a view to avoiding the need for strengthening.

DIC methodology: DIC system providing live results of the bearing movement and rotation.

Value added: Measurement carried out without the need for rail possessions and road closures. Night works and working at height were avoided. All setting up, data capture and packing away was completed within a few hours.

Monitoring challenge: Long term monitoring of the expansion joint movement and rotation due to temperature.

DIC methodology: 3 sync cameras providing simultaneous data of joint movement and rotation. DIC system controlled remotely.

Value added: Outcome of the monitoring provided previously unavailable monitoring data and informed the next steps with respect to the maintenance strategy. Excellent correlation with the temperature data was obtained.

Monitoring challenge: Dynamic monitoring of displacement of an impact damaged girder with a view to avoiding the need for strengthening and immediate remedial measures.

DIC methodology: A single camera system providing live results on displacements.

Value added: The results were obtained within a few hours, without the need for any rail or road possessions, quantified the true behaviour of the investigated structures leading to the conclusion that the defects could be tolerated.

Great Belt Bridge(Client: Sund & Bælt)

DLR Warton Road Bridge (Client: TfL - Docklands Light Railway)

Bletchley Flyover(Client: EWR Alliance / Network Rail)

Humber Bridge(Client: Humber Bridge Board)

Monitoring challenge: Monitoring of the half joints, portal piers and bridge articulation verification under train load.

DIC methodology: Dynamic testing to monitor the half-joints, tee piers and longitudinal and vertical movement of the deck under live loading with the structure subject to braking load from a 230t locomotive.

Value added: Measurements carried out without the need for rail possessions. Bespoke algorithms have been used to analyse the measurement data. Works involving working at height were avoided.

Monitoring challenge: Dynamic monitoring of the deck displacements and rotations from a distance of 700 m. Measurements carried out during the night.

DIC methodology: A single camera system providing live results on deck displacements and rotations.

Value added: The innovation of using DIC in combination with spotlights to conduct a load test at night in the dark without disrupting traffic created new application opportunities. The outcomes of the monitoring informed the next steps with respect to the maintenance strategy. The results were used to validate the FE model and verify the theoretical assumptions.

Monitoring challenge: Dynamic monitoring of the girder displacements in multiple locations.

DIC methodology: A camera system providing live results on vertical and horizontal displacements.

Value added: Measurement carried out without the need for road closures. Night works and working at height were avoided. All setting up, data capture and packing away was completed within a few hours.

Gade Valley Viaduct(Client: Connect Plus)

Slochd Beag Bridge(Client: Transport Scotland)

Monitoring challenge: Dynamic monitoring of the bridge girder displacements in multiple locations.

DIC methodology: A single camera system providing live results on bridge girder movement due to traffic.

Value added: Outcome of the monitoring was used to validate the FE model and informed the assessment scheme. All setting up, data capture and packing away was completed within a few hours.

Strain / Stress monitoring, Fatigue Detail Applications

Unmanned Aerial Vehicle (UAV), Geospatial Applications

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Substructure, Pier, Foundation Applications Loading Platform applications

Monitoring challenge: Long term monitoring of wind-induced hanger vibrations and traffic-induced deck displacements.

DIC methodology: Development of a new 24/7 night-vision based system providing real-time data on hanger vibrations.

Value added: DIC monitoring provided more reliable and better-quality data over the use of accelerometers and helped to gain a better understanding of the behavior of hangers, informing the next steps with respect to the maintenance strategy.

Great Belt Bridge(Client: Sund & Bælt)

Monitoring challenge: Dynamic monitoring of strain at fatigue sensitive detail with a view to avoiding the need for strengthening and immediate remedial measures.

DIC methodology: A single camera system providing live results on strain.

Value added: The results were obtained within a few hours, without the need for any rail or road possessions, the monitoring quantified the true behaviour of the investigated structures, leading to the conclusion that the defects could be tolerated.

DLR Wick Lane Bridge (Client: TfL - Docklands Light Railway)

Edinburgh North Bridge(Client: City of Edinburgh Council)

Monitoring challenge: Strain monitoring of structural members to determine the levels of stress that they were currently subjected to.

DIC methodology: A single camera system providing live results on the strains in critical locations.

Value added: Cost effective solution in comparison to other traditional techniques. Non-intrusive nature of strain monitoring technique. Successful strain monitoring of an iconic structure.

Monitoring challenge: DIC strain map monitoring at the cross frame and near the butt weld.

DIC methodology: A camera system providing live results on the strain in critical locations.

Value added: A strain map (0.4m x 0.3m) helped to better understand the stresses occurring at the cross frame and welded details, consequently increasing the understanding of risk of future failures.

Gade Valley Viaduct (interior girder)(Client: Connect Plus)

E75/S52 Expressway Cross Border Bridge(Client: General Directorate for National Roads & Highways - Poland)

Monitoring challenge: Drone-assisted structural monitoring of 30 m tall concrete piers. Detect and quantify the defects (concrete cracks) using drone images.

DIC methodology: Orthophoto maps used to quantify the cracks using state-of-the-art image processing algorithms.

Value added: 3D point cloud based BIM model for life-cycle management was built using the data captured using drone-assisted monitoring.

Monitoring challenge: Static & dynamic monitoring of the pillar and foundation displacements due to traffic/HGV in multiple locations.

DIC methodology: DIC system providing live results on the pillar & foundation displacements.

Value added: The results obtained quantified the actual behaviour of the pillars/substructure. DIC measurements informed a geotechnical study that saved millions of DKK on unnecessary soil strengthening. All setting up, data capture and packing away was completed within a few hours.

Monitoring challenge: Structural monitoring of platforms undergoing loading operation over railway.

DIC methodology: A single camera system providing live results on the displacements in critical locations.

Value added: The findings of the DIC monitoring provided recommendations for remedial measures to be implemented to the structures for both short-term and long-term use. The results were used to quantify the remaining fatigue life of structures.

Køge Bugt Highway(Client: The Danish Road Directorate)

AML Port of Buchanan(Client: ArcelorMittal)

Cable, Hanger Applications

Humber Bridge(Client: Humber Bridge Board)

Monitoring challenge: Wire strain monitoring of the hangers under traffic load.

DIC methodology: Non-contact, single camera system providing live results on wire strain.

Value added: Outcome of the monitoring was used to calibrate the 3D FE model of the bridge and informed the next steps with respect to the hanger replacement strategy.

Awards and Commendations

Our Work

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Martin Duus Havelykke (Great Belt Bridge - Maintenance Manager):

DIC helped to better understand the behavior of expansion joint and cables and informed next steps with respect to maintenance strategy.

Tony Nicholls (M25 Highway Connect Plus Services - Professional Head of Structures):

DIC allowed structural monitoring of key structural components without any traffic disruption.

Alex Heward (Innovation Manager - EWR / Laing O’Rourke):

DIC was succesfully used to establish the critical behaviour of the certain elements of the structure under the application of live load.

Client Recommendations

Institution of Structural Engineers

National Transport Awards(Excellence in Technology)

International Association for Shell

and Spatial Structures

https://www.youtube.com/watch?v=JJoKjwLgdHY