Multimodal Condition Assessment of Bridge

Decks by Non-Destructive Evaluation

2010 Midwest Bridge Preservation

Partnership Annual Meeting October 12-14, 2010

AISI Bridge Task Force

222010AASHTO T-14 Committee

Cedar Rapids, IA

April 8, 2008

Multimodal Condition Assessment of

Bridge Decks by Non-Destructive Bridge Decks by Non-Destructive

Evaluation (NDE) and Its ValidationNenad Gucunski, Ruediger Feldmann, Francisco Romero, Sabine

Kruschwitz,

Rutgers University

Center for Advanced Infrastructure and Transportation (CAIT)

Norm McDonald, Ahmad Abu-Hawash

Iowa Department of Transportation

Location of Tested Bridges

Iowa Bridge Deck Evaluation

Implemented NDE technologies

• Ground penetrating radar (GPR)

• Impact echo (IE)

• Ultrasonic pulse echo

• Ultrasonic surface waves

• Half-cell potential

• Electrical resistivity

Complementary evaluations/validations

• Coring

• Chain drag

NDE Techniques

GPRGPR Ultrasonics

Resistivity

Seismic/Ultrasonic

Impact Echo

Half-Cell

Ultrasonics and

Impact Echo

Deterioration Types Vs. NDE Method

Corrosion• Half-cell potential – Likelihood of corrosion

• Electrical resistivity – Potential for corrosive environment

• GPR – Potential for corrosive environment• GPR – Potential for corrosive environment

Concrete Degradation• Ultrasonic surface waves (USW) – Modulus degradation

• GPR – Likelihood of deterioration

Delamination• Impact echo

• Ultrasonic pulse echo

• GPR – Likelihood of delamination in severely attenuated areas Bridge Monitoring: NDE

Bridge Deck Condition Assessment

REBAR CORROSION DELAMINATION SPALLING

BRIDGE DECK CONDITION

GPR

IMPACT ECHO

HAMMER SOUNDING/CHAIN DRAG

VISUAL INSPECTION

TIME

HALF-CELL POTENTIAL

ULTRASONICS

Data Collection – Test Grid

Half-Cell Corrosion Potential

Electrical Resistivity – Wenner Probe

Electrical Resistivity, kohm/cm

Ground Penetrating Radar (GPR)

GPR – Raw Scan and Condition Map

Deteriorated Zone

De-bonded O/L

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

DISTANCE FROM EAST ABUTMENT (FEET)

Top Rebar Amplitude (Normalized dB) - DEPTH CORRECTED

0

10

20

-22 -20 -18 -16 -14 -12 -10 -8

Impact Echo and Ultrasonic Testing

Stepper – Ultrasonics and Impact Echo

Evaluation of Modulus and Deck Thickness by UBW and IE

travel time

t

A

f

returnfrequencyVp

thickness

21

AIEUBW

1 2

IE on a Delaminated Deck

DELAMINATION

IMPACT

SOURCE

t = V / 2ft

p

RECEIVER

T

Depth, %

75250 100

Amplitude

Frequency, kHz

4020100 30

Amplitude

50

f

DELAMINATED

SOLID

Deck Condition Grades

Amplitude

RECEIVERIMPACT

SOURCE

T

GOOD (INTACT) CONDITION

Concrete is well

bonded and no signs

of delamination are

detected.

Amplitude

RECEIVERIMPACT

SOURCE

T

FAIR CONDITION

Concrete is bonded

or in contact, but

there are signs of

delamination at

some depths.

Frequency, kHz

4020100 30fTFrequency, kHz

4020100 30fT

Frequency, kHz

4020100 30

Amplitude

DELAMINATION

IMPACT

SOURCE

t

f

RECEIVER

T

DELAMINATED

SOLID

SERIOUS CONDITION

There is complete

loss of bonding and

separation of concrete

layers.

Frequency, kHz

4020100 30

Amplitude

DELAMINATION

IMPACT

SOURCE

t

f

POOR CONDITION

RECEIVER

T

DELAMINATED

SOLID

Delamination has

occurred, however

grain to grain contact

between the two

concrete layers

exists.

Impact Echo Delamination Assessment

Note:

White lines

represent

boundaries

determined

by chain

drag

Modulus Evaluation by USWRT. I-495S - SPAN6

10

12

14

16

Longitudinal distance, m

Shear Mod.(MPa)14700+

14000 to 14700

13300 to 1400012600 to 13300

RT. I-495S - SPAN 6Two Left Lanes

SHEAR MODULUSDISTRIBUTION

Modulus

vs.

depth

Average

Modulus0 1 2 3 4 5 6

Lateral distance, m

0

2

4

6

8

Longitudinal distance, m

12600 to 13300

11900 to 1260011200 to 11900

10500 to 11200

9800 to 10500

9100 to 98008400 to 9100

7700 to 84007000 to 7700

Good

-800

-600

-400

-200

0

mV-21.75

-18.75

-15.75

-12.75

-9.75

dB

Good

Fair

Poor

Serious

No

Signal1.0

2.0

3.0

4.0

5.0

6.0

cm

O1

mV

dB

O2Good

Fair

Poor

Serious

No

Signal

kohm*cm

O2

O6 dBmV

Good Fair Poor Serious No

signal

kohm*cm

Conclusions

• Condition assessment of bridge decks using NDE

technologies has shown their ability to detect and

characterize different types and levels of deterioration.

• Half-cell potential and electrical resistivity measurements enable

assessment of likelihood and severity of corrosion.

• GPR provides information about deterioration/alteration of

concrete.

• Impact echo and ultrasonic measurements enable detection and

characterization of delamination in the deck. Delamination

detection was validated through the comparison with cores

taken and selected locations.

• Complementary approach in NDE bridge deck evaluation

provides a more comprehensive condition assessment.

Thank you!

Questions?