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April. 2013
Masato Matsumoto
Bridge Assessment Methods Using Image Processing and Infrared
Thermography Technology
1. Background2. Non-destructive Bridge Assessment Method3. Practical Application Pilot Projects4. Summary and Conclusions
Presentation Outline
1
2
Traditional and New Approach
New Technology
High Definition Video Digital Camera Infrared Camera
Snooper Truck Bucket Truck Hammer Sounding
Traditional Approach
Typical Traditional Inspection Result
3
Current Practice for Documentation of Inspection Results – Worded descriptions transcribed by hand.
More efficient, objective and safer bridge inspections can be realized only through technological improvements.
Long-Term Bridge Monitoring
An objective digital record is essential for monitoring long-term bridge performance and maintenance budget planning.
Year 2012 Year 2014 Year 2016 Year 2018
?4
Infrared Imagery TechnologyC
oncr
ete
surfa
ce te
mp.
(°C
)
morning
Sound area
Noon evening night
Temp.differences
Concrete surfaceHeat flow
Imagery Period A
Imagery period B
Imagery Period A
Air temp.
Inner Crack
Delaminated areaSound areaDelaminated area
Sound area
Imagery Period B
Delaminated area
Concrete surface
Heat flow
Heat flow Heat flow
Inner Crack
5
6
Interpret Thermal Data into Damage Ratings
Damage Rating Definition
Crack Location RatingDamage Rating
Temp. Distribution
rebar
Concrete surface
Tem
p.(℃)
Depth�4㎝
Reaching surface
crack Indication
Caution
CriticalEmergent Action Required
crackrebar
Depth�2㎝
crack
rebar
Concrete surface
Concrete surface
Concrete surface
Tem
p.(℃)
Tem
p.(℃)
Concrete surface
Concrete surface
Automatic Camera System (ACS)
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8
Photographing by HDV
#3#2#1
Combined Image of full surface continuity
Camera
8
Deck Top Scanning System
4.0 m
80 km/h(50mph)
GPS
Speed meter
Line sensor cameraIR cameraGenerator
2.6 kVA
Line sensor : 0.8 mm/pixel @ 50mph, Width = 4.0m→ detectable crack width = 0.2 mm
Color images are acquired
PC
9
Advantages of New Inspection Technologies
Overcome some shortcomings of human subjectivity Providing an objective digital record for historical
inspection data comparisons and maintenance budget forecasts.
Reducing time for documentation of current bridge condition (Improve efficiencies in bridge inspection resource application).
Identifying areas of bridges to be targeted for closer inspection and/or future monitoring.
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Pilot Project in Florida
Government
IndustryAcademia
11
Pilot Project Location
● FDOT District 5● UCF
● Bridge SR#5
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ACS Photographing (Deck Underside)
Deck #5
Deck #6
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Evaluation by FDOT Bridge Inspector
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Crack Widths Evaluation at Deck Underside
Crack#1Crack#2-1
Crack#2-2
Crack#3-1
Crack#3-2
Crack ACS Crack Detection FDOT Inspector Match
Crack #1 < 0.010″ 0.006″ OK
Crack # 2-1 < 0.010″ 0.007″ OK
Crack # 2-2 0.010″~0.030″ 0.025″ OK
Crack # 3-1 0.010″~0.030″ 0.016″ OK
Crack # 3-2 < 0.010″ 0.010″ OK
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IR Test Piece at Deck Underside
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1cm
2cm
3cm
CRITICAL CAUTION OBSERVATIONOK OK OK
Detectable Depth
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Temperature Recorded at Deck #6 Underside
07/11 07/12 07/13 07/14
Thunderstorm Rain
Thunderstorm Rain
RainThunderstormThunderstorm Shine
07/10
Concrete
Air
@ Melbourne, FL
IR Inspection Results (Deck #6 Underside)
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Hammer Sounding Infrared ID # IrBAS Result Match
Plastic inside 607 Detected
South
North
(Minimum Detectable Scale = 4.4mm)Photographed at PM3:00, August 1,
CRITICAL CAUTION OBSERVATION601 4.31602 1.94603 1.51604 4.84605 2.15606 1.29607 0.11608 2.15609 0.54610 3.77611 0.32612 1.29613 1.29614 2.83615 0.55616 13.95Total 21.06 16.06 5.70
ID#POTENTIAL SPALL AREA (sq. ft.)
Hammer Sounding by FDOT
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Hammer Sounding by FDOT
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(Deck #6 Bridge Underside - #607)
#607Before hammer Sounding
#607After hammer Sounding
Plastic sheet appeared
(Thermography) (Software Output)
Deck Top Scanning for I-4 Bridges in Orlando
Traditional Technique and New Approach
BRAND BOOK 22
Deck Top Scanning System
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Infrared Camera Line Sensor Camera
Speed Meter
Infrared Deck Scanning
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I-4 over South Street Bridge West-bound
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Deck Surface Image (#750050 - WB) – 2nd lane
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Insignificant Moderate Severe
Crack Size < 1/16’’ 1/16’’ to 1/4’’ >1/4’’
Crack Map (1/64” (0.3mm) or Greater)Deck Surface Crack Map
Infrared Thermography Image
Infrared Software Output
East Side Span
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Lane 1
Longitudinal crack
Transversalcrack
Hexagonalcrack
Lane 2
Hexagonalcrack
Transversalcrack
Longitudinalcrack
Delamination Hexagonalcrack
Pot hole
Lane 3Transversal
crack
Lane 4No significant
crack
Delamination
Comparison between Visual and IR Images (3)
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Construction Joint between old deck and new additional deck at 2nd lane
Typical Cracking Pattern for Concrete Bridge Deck Surface
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Typical Cracking Pattern for ASR-Induced Concrete Bridge Deck (FHWA, 2011)*
Map Cracking, Discoloration and Possible Delamination on the Scanned Bridge Deck Surface
* Federal Highway Administration (FHWA, 2011), Alkali-Silica Reactivity Field Identification Handbook (FHWA-HIF-12-022)
‘Initially cracks are initiated close to the expansion joints and tend to be orientated perpendicular to the joint. As ASR advances, the cracks spread around the perimeter of the slabs and there is often little or no cracking in the center of the slab. The reason that the region around the joints is more prone to cracking is because (a) there is often more moisture available at the joints, (b) there is less restraint to expansion close to the joints, and (c) mechanical stresses to vehicular loading are higher at the joints’
Surface Pop-out of Aggregates
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‘Alkali-reactive aggregates undergoing expansion near the concrete surface may induce the detachment of a portion of the mortar overlying the aggregate and leaving the reactive aggregate exposed. Such features are termed ‘pop-outs’.’
* Federal Highway Administration (FHWA, 2011), Alkali-Silica Reactivity Field Identification Handbook
(FHWA-HIF-12-022)
Surface Pop-out of Aggregates on the Scanned Deck Top Surface
An Example of Exudation Associated with Cracks
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An Example of Exudation Associated with Cracks(FHWA, 2011)*
An Example of Exudation Associated with Cracks (Observed in the scanned deck underside)
* Federal Highway Administration (FHWA, 2011), Alkali-Silica Reactivity Field Identification Handbook
(FHWA-HIF-12-022)
‘Surface gel exudations are also a common feature of ASR. The exudation may be alkali-silica gel or lime (or both) leaching from the cracked concrete.’
Condition States Based on FHWA, 2012
32
West (South) - bound
Element Level Condition State
1 (good)
2 (fair)
3 (poor)
4 (severe)
East side span Center span West side span
Lane 4
Lane 3
Lane 2
Lane 1
* Condition States Based on:Federal Highway Administration (FHWA, 2012), Alkali Silica Reactivity Surveying and Tracking
Guidelines (FHWA-HIF-12-046)
Deck Surface Distressed Area Calculation
33
Insignificant Moderate Severe
Crack Size < 1/16’’ 1/16’’ to 1/4’’ >1/4’’
Crack Map (1/64” (0.3mm) or Greater)
Distressed Area
(Including Cracks > 1/16” (or 1.6mm) and/or Potholes
Deck Surface Distressed Area Calculation (Example)
Total Deck Area(ft2)
Distressed Area(ft2)
Percentage ofDistressed Area
(%)
2,099.08 48.16 2.3
NBI Condition State Description
Condition State 1(good)
The combined area of unsound wearing surface (spalls, delaminations, delaminated temporary patches) is 2% or less of the total deck area
Condition State 2(fair)
The combined area of unsound wearing surface (spalls, delaminations, delaminated temporary patches) is more than 2% but not more than 10% of the total deck area
Condition State 3(poor)
The combined area of unsound wearing surface (spalls, delaminations, delaminated temporary patches) is more than 10% but not more than 25% of the total deck area
Condition State 4(severe)
The combined area of unsound wearing surface (spalls, delaminations, delaminated temporary patches) is more than 25% of the total deck area
Prioritizing Bridge Repair/Rehabilitation Program
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Phase 1: Pre-Screening(Video Image)
Keep the Recorded Image
Flagged Spans
Not Flagged
Phase 2: Prioritization (Determine Deterioration Type)
Spans in Red Phase 3: Detailed Bridge Scan (from
Underside)
Deck Repair/Rehab Planning
Lane Span % of Distressed Area Condition State1 20.0 32 1.6 13 1.8 14 5.7 21 6.7 22 3.8 23 1.2 14 9.0 21 2.7 22 2.9 23 4.5 24 3.6 21 1.5 12 1.2 13 1.3 14 1.7 1
1
2
3
4
NBI Condition States
Corridor/Network Level Bridge Inspection
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1. The pilot application for bridge underside inspection in Florida was successfully finished.
2. The accuracy of the imaging and IR inspection technologies were evaluated by FDOT certified bridge inspector through traditional technique
3. Employing NDE deck top scanning systems can improve distressed area mapping accuracy, reduce inspection time and cost.
4. Applying deck scanning system to corridor-level bridge deck will allow transportation agencies to prioritize their bridge deck repair/rehabilitation program
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Special thanks to..Florida Department of Transportation District 5West Nippon Expressway Company Limited
Ms. Azusa Watase Mr. Evan Prado
Ms. Manabu YoshinagaMs. Shizu Yoshida
Fuji Engineering, Ergo VisionNEXCO-West Eng. Shikoku
for their cooperation and support for this project
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