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Condition Assessment of Concrete Bridge Elements using Active Infrared Thermography
Jason CattelinoKhatereh Vaghefi
Professor Tess Ahlborn, FACI, FPCIMichigan Technological University
Undergraduate Research in Concrete Materials, Structural Design, and ConstructionApril 13, 2015; Kansas City, MO, USA
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The Big PictureThe NeedBackground
https://www.armtec.com/photo-album/nu-girders/
OverviewIn the LabField ApplicationDiscussion
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The Big PictureThe NeedBackground
OverviewIn the LabField ApplicationDiscussion
$170 Billion to Improve Current Conditions and Performance 2010 FHWA Conditions and Performance Report
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Common Types of Deterioration
The Big PictureThe NeedBackground
Spalling
http://alwayscivil.blogspot.com/2013/06/concrete-encased-steel-beams.html
Corrosion
http://bridgehunter.com/photos/20/79/207944-L.jpg
Cracking
http://www.foundationprosfl.com/concrete-crack-repair.html
OverviewIn the LabField ApplicationDiscussion
Concrete Pier
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Common Types of Deterioration
http://www.ndtoolbox.org/content/bridge/deck-delamination-description
OverviewIn the LabField ApplicationDiscussion
The Big PictureThe NeedBackground
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Review of Current Technologies
OverviewIn the LabField ApplicationDiscussion
The Big PictureThe NeedBackground
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Passive Infrared Thermography
OverviewIn the LabField ApplicationDiscussion
The Big PictureThe NeedBackground
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Active Infrared Thermography
OverviewIn the LabField ApplicationDiscussion
The Big PictureThe NeedBackground
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Research Objectives
OverviewIn the LabField ApplicationDiscussion
The Big PictureThe NeedBackground
1) Conduct a preliminary lab investigation to validate the application of active IR thermography to concrete elements.
2) Evaluate active IR thermography through a proof of concept field application.
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Lab Testing
ExperimentationAnalysisFindings
Specimens and Set-up• 3 ft. by 3 ft. test slabs• Simulated delams at various depths• Tripod mounted camera and heater• General Parameters
• Heater distance = 3.5 ft.• Camera distance = 6 ft.• Heat time = 15
min.
Parametric Study:• Heat time• Heater distance• Thermal Concentrations
OverviewIn the LabField ApplicationDiscussion
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Lab Testing: Analysis Methodology
Analysis Procedures based on Absolute Contrast1) Define representative area above delam2) Define local reference area3) Monitor temperature contrast over time4) Determine observation time
OverviewIn the LabField ApplicationDiscussion
ExperimentationAnalysisFindings
Depth of Defect Dependent on:• Observation time• Material properties
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Lab Testing: Key Findings1) Width-to-Depth Investigation2) Depth of Defect3) Heat Time
OverviewIn the LabField ApplicationDiscussion
ExperimentationAnalysisFindings
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Proof of Concept Field Application – 6/24/2014
Locations and ProcedureData and ProcessingFindings
Franklin St. over US-131 NB & SB
OverviewIn the LabField ApplicationDiscussion
Test Equipment
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FLIR SC640• 640 x 480 pixels• High temperature resolution of 0.1 oF• Graphical user interface• Real time thermal images and temperature output• $50,000
FLIR Tau 2• 336 x 256 pixels• 1.75 in. x 1.75 in. x 1.2 in.• Records data to external memory• Digital number output• $4000
Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
Active IR Field Demo Set-up and Access
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Access and Testing Procedure
Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
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FLIR SC640FLIR Tau 215 min 15 min
30 min 30 min
Underside of Bridge Deck (Test B1: 15 min. heat time)
SC640 and Tau 2 Data Comparison
Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
Data Processing and Interpretation: Area
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Ground Truth Delam Area
1) Align thermal and optical images2) Project boundary of thermal image to
optical image, defining total area3) Construct polygon representing delam4) Determine % area
Suspected Delaminated Area
Sound Concrete
Suspected Delaminated Area
Sound Concrete
Thermal Image Delam Area
1) Determine time of max delam contrast2) Construct polygon representing delam3) Determine % area
Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
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TEST B1: 15 min. Heat Time
TEST A1:5 min. Heat Time
TEST C1: 15 min. Heat Time
TEST A2:15 min. Heat Time
Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
Field Demonstration Key Findings1) Active IR thermography is adequate for detecting delaminations on the
underside of bridge decks2) Applicable to pier caps and fascia beams3) Lower cost, lower resolution cameras are adequate for delam area4) Thermal IR can improve inspector accuracy
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Locations and ProcedureData and ProcessingFindings
OverviewIn the LabField ApplicationDiscussion
1) Inspector input• Equipment cost• Equipment portability• Test time
2) Automated detection algorithm• Threshold analysis• Higher order statistics• Frequency domain analysis
3) Pilot study• 5-15 bridges
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Conclusions – Bottom of Deck EvaluationImplementationQuestions and Comments
The Path to Implementation
OverviewIn the LabField ApplicationDiscussion
http://modotblog.blogspot.com/
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Contact Information: Jason Cattelino, [email protected]
Questions and Comments
OverviewIn the LabField ApplicationDiscussion
ImplementationQuestions and Comments
