This document discusses automated fault measurement of concrete pavements based on pavement profile data. It presents challenges in measuring faults accurately using profiles, including joints with spalls or cracks. The revised AASHTO R36 standard for evaluating faulting requires validating automated measurements with physical devices at joint spacings. The ProVAL software identifies joint locations in profiles using various detection methods and computes faults by fitting profile slices on each side of joints. Widespread use of automated fault measurement can help agencies meet federal reporting needs in a consistent, efficient manner.

1. International Symposium on Pavement Performance
Trends, Advances, and Challenges
December 5, 2011
Practical Implementation of
Automated Fault Measurement
Based on Pavement Profiles
By
George Chang, PhD, PE, Transtec Group
James Watkins, PE, MSDOT
Bob Orthmeyer, PE, FHWA

2. Acknowledgement
• FHWA
– Bob Orthmeyer
• MSDOT
– James Watkins, Cindy Smith, Grady Aultman,
Alan Hatch, Alex Middleton, and Marta Charria
• FLDOT
– Abdenour Nazef, Alex Mraz, and etc.
• University of Michigan
– Steve Karamihas

4. What is ProVAL AFM
• Automated Fault Measurement
based on profile data
• FHWA HPMS requires joint fault data
• Implement revised AASHTO R36
“Standard Practice for Evaluating
Faulting of Concrete Pavements”

5. High-speed Inertial Profiler
Speed/Distance
Measuring System Computer
Height Sensor Accelerometer

6. Pavement Profile Data
Right Elevation Profile (mm)
40
20
0
-20
complete profile
high-pass filtered (91 m)
-40
0 50 100 150
Distance (m)

7. Convension of Faulting
Traffic direction Positive Faulting
Approach Slab
Departure Slab
Joint
Negative Faulting
Departure Slab
Approach Slab
Joint

8. Challenges for AFM - Pavements
• Filled joints
• Closed joints
• Spalled joints
• Curl/warp features
• Cracks and other distresses/patches
• Joint spacing patterns
• Skewed joints
• Grade
Courtesy of MSDOT

9. Example of Spalled Joints
Courtesy of MSDOT

10. Example of Negative Faults
Courtesy of MSDOT

11. Example of Transverse Cracks
Courtesy of MSDOT

12. Challenges for AFM - Profiles
• Repeatability/accuracy
• Fault validation tests with physical
devices
• Sampling intervals
• Laser foot prints
• Repeated profile runs
• DMI drifts

13. Revised AASHTO R36-04
• Feet Spacings for physical devices
• Automated procedure based on
pavement profiles
• Validation devices for automated
procedure

14. Physical Fault Devices
Georgia Fault Meter
Courtesy of FLDOT

15. Feet Spacings for Physical Devices
Faultme
A
ter
B
Leg1
Leg2
L1 C
D
L2 Leg3
Approach Slab
L3
Departure Slab
Joint
C, D = 3” to 8.9”
76 to 226 mm

16. Profile Requirements
• Repeatability and Accuracy
requirements (AASHTO R56)
• Fault validation with physical devices
• No additional pre-filtering
• Collect profiles at both wheel tracks
• Max sampling intervals
– Basic level: 1.5” (38 mm)
– Advanced level: 0.75” (19 mm)

17. Candidate Field Validation Devices
MS DOT
Top View
Handle Handle
Side View Transducer
Retractable
wheel
B = 12”
L1 L2 L3
A=18”
B1= 6” B2=6”

18. Candidate Field Validation Devices
FL DOT

19. ProVAL AFM
• Multiple profiles
• Joint locations ID
• Edit joint locations
• Compute faults
• Individual faults and segment summary

20. Joint ID Methods
• Downward Spike (FHWA Curl/Warp)
• Step (MSDOT)
• Curled-Edge

21. Downward Spike Detection
• Anti-smoothing filtering
• Normalize the filtered profile (/RMS)
• Detect profile spikes (-4.0)
• Screen joint locations

22. Step Detection
• Deduct profile elevations between
consecutive data points
• Detect large step (0.08 in.)
• Screen joint locations

23. Curled-Edge Detection
• Bandpass filtering
• Rolling straightedge simulation
• Detect high RSE (0.12”)
• Screen joint locations

24. Joint ID Methods Selection
• Downward Spike Detection
– Shorter sampling intervals
– Downward spikes present
• Step Detection
– Apparent faults present
• Curled-Edge Detection
– Noticeable slab curling and warping

25. Joint ID Methods Selection
• Downward Spike

26. Joint ID Methods Selection
• Step

27. Joint ID Methods Selection
• Curled-Edge

28. Fault Computation
• Crop a profile segment
• Separate profile slices
• Least-square fits
• Compute faults

29. Profile Slices

30. Slicing and Fitting
-230.00
-1.5 -1 -0.5 0 0.5 1 1.5
-232.00
Faulting
Elevation (mm)
-234.00
-236.00
150 mm
-238.00
-240.00
1219 mm 1219 mm
-242.00
-244.00
Normalized Distance (m)
Profile Fitted Shape-Approach Fitted Shape-Leave

31. Fault Computation
-230.00
-1.5 -1 -0.5 0 0.5 1 1.5
-232.00
Faulting
Elevation (mm)
-234.00
-236.00
150 mm
-238.00
-240.00
1219 mm 1219 mm
-242.00
-244.00
Normalized Distance (m)
Profile Fitted Shape-Approach Fitted Shape-Leave
Faulting
150 mm
3” to 8.9”
76 to 226 mm

32. Fault Computation (cont’d)
0 0.5
Faulting
150 mm
3” to 8.9”
76 to 226 mm
Fault = Avg(Fault I = 1 to N)

33. ProVAL AFM Inputs

34. ProVAL AFM Joint ID

35. ProVAL AFM Joint Faults

36. ProVAL AFM Joint Faults

37. ProVAL AFM Joint Faults
Summary

38. What’s Next
• ProVAL AFM Revision
– March 2012
• AASHTO R36-12
– Revision : March/April 2012
– Ballot : April/May 2012
– New Standard: Summer 2012

39. Save Lives with ProVAL AFM

40. Thank You !
Dr. George Chang, PE
Transtec Group
USA
gkchang@thetranstecgroup.com