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ASTM E17 Symposium 2011. It describes the algorithm, implementation, and validation of the ProVAL Automated joint Fault Measurement (AFM) tool.
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ByGeorge Chang, PhD, PE, Transtec Group James Watkins, PE, MSDOTBob Orthmeyer, PE, FHWA
Practical Implementation of Automated Fault Measurement
Based on Pavement Profiles
International Symposium on Pavement PerformanceTrends, Advances, and Challenges
December 5, 2011
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
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”
High-speed Inertial Profiler
Accelerometer
Computer
Height Sensor
Speed/Distance Measuring System
Pavement Profile Data
complete profile high-pass filtered (91 m)
0 50 100 150Distance (m)
-40
-20
0
20
40Right Elevation Profile (mm)
Convension of Faulting
Approach SlabDeparture Slab
Joint
Approach SlabDeparture Slab
Joint
Positive Faulting
Negative Faulting
Traffic direction
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
Example of Spalled Joints
Courtesy of MSDOT
Example of Negative Faults
Courtesy of MSDOT
Example of Transverse Cracks
Courtesy of MSDOT
Challenges for AFM - Profiles
• Repeatability/accuracy• Fault validation tests with physical
devices• Sampling intervals• Laser foot prints• Repeated profile runs• DMI drifts
Revised AASHTO R36-04
• Feet Spacings for physical devices• Automated procedure based on
pavement profiles• Validation devices for automated
procedure
Physical Fault Devices
Courtesy of FLDOT
Georgia Fault Meter
Feet Spacings for Physical Devices
Joint
Faultmeter
L1
L2
L3
A
B
CD
Approach Slab
Departure Slab
Leg1
Leg2
Leg3
C, D = 3” to 8.9”76 to 226 mm
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)
Candidate Field Validation Devices
MS DOT
B2=6”B1= 6”A=18”L1 L2 L3
Top View
Side View
Handle
Retractable wheel
Handle
Transducer
B = 12”
Candidate Field Validation Devices
FL DOT
ProVAL AFM
• Multiple profiles
• Joint locations ID
• Edit joint locations
• Compute faults
• Individual faults and segment summary
Joint ID Methods
• Downward Spike (FHWA Curl/Warp)
• Step (MSDOT)
• Curled-Edge
Downward Spike Detection
• Anti-smoothing filtering
• Normalize the filtered profile (/RMS)
• Detect profile spikes (-4.0)
• Screen joint locations
Step Detection
• Deduct profile elevations between consecutive data points
• Detect large step (0.08 in.)
• Screen joint locations
Curled-Edge Detection
• Bandpass filtering
• Rolling straightedge simulation
• Detect high RSE (0.12”)
• Screen joint locations
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
Joint ID Methods Selection
• Downward Spike
Joint ID Methods Selection
• Step
Joint ID Methods Selection
• Curled-Edge
Fault Computation
• Crop a profile segment
• Separate profile slices
• Least-square fits
• Compute faults
Profile Slices
Slicing and Fitting
-244.00
-242.00
-240.00
-238.00
-236.00
-234.00
-232.00
-230.00-1.5 -1 -0.5 0 0.5 1 1.5
Normalized Distance (m)
Elev
atio
n (m
m)
Profile Fitted Shape-Approach Fitted Shape-Leave
Faulting
150 mm
1219 mm 1219 mm
Fault Computation
-244.00
-242.00
-240.00
-238.00
-236.00
-234.00
-232.00
-230.00-1.5 -1 -0.5 0 0.5 1 1.5
Normalized Distance (m)
Elev
atio
n (m
m)
Profile Fitted Shape-Approach Fitted Shape-Leave
Faulting
150 mm
1219 mm 1219 mm
Faulting
150 mm3” to 8.9”76 to 226 mm
Fault Computation (cont’d)
0 0.5
Faulting
150 mm3” to 8.9”76 to 226 mm
Fault = Avg(Fault I = 1 to N)
ProVAL AFM Inputs
ProVAL AFM Joint ID
ProVAL AFM Joint Faults
ProVAL AFM Joint Faults
ProVAL AFM Joint Faults Summary
What’s Next
• ProVAL AFM Revision – March 2012
• AASHTO R36-12– Revision : March/April 2012
– Ballot : April/May 2012
– New Standard: Summer 2012
Save Lives with ProVAL AFM
