practical implementation of automated joint fault measuerment

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

Thank You !

Dr. George Chang, PETranstec Group

USAgkchang@thetranstecgroup.com