Converting from Profilograph-Based
to Profile-Based Ride Measurement
for PCCP Pavements
North Dakota Spring Concrete
Workshop
Sustainability in Pavements
What to Expect
Equipment Changes (Ames LISA)
Specification Changes (PI to IRI)
Learning Curve
Increased
Complexity
I
dC
l it
More Active Research
March 11th, 2009
Benefits of Changing to Profile
Based Ride Measurement
Better Relationship to Consumer Ride Comfort
Allows Cradle to Grave Pavement Management
Links design, construction, maintenance, and
pavement
pa
e e t eevaluation
a uat o aandd management
a age e t
Closed-loop Feedback System is Possible
Relationship to MEPDG
IRI is a Measure of Performance in the New Guide
Can Use AASHTO Standards and FHWA ProVAL
Faster and Safer
States Using Various PCCP
Smoothness Index Types
www.smoothpavements.com
Obstacles to Converting to ProfileBased Measurement
New Equipment Costs
Transition Time to Convert
Relationship between PI & IRI
S
Sensor
Issues
I
Repeatability and Reproducibility
Certification Process
More Complex Processing and Analysis
Use of Incentives By State
www.smoothpavements.com
1
Measurement of Road Profile
Insert a Photo of one of your pavements
Evolution of Smoothness Equipment
1900s – Present
Straight Edge (10-12 ft)
1940s –Present
Profilograph
(California, Rainhart, Ames)
1940 - 1980s
1940s
1980
Response Type
(Roughometer, Mayes
Meter)
1965 – Present
Inertial Profiler
(GM Profilometer)
1990s - Present
Inclinometer
California Profilograph Evolution
California
Mobile
Profilograp
h
Roughograph (5 ft Straightedge)
1955-1960 1st 25ft beam
1940’s 10 ft Beam 16 Wheels
History of Road Smoothness
Measurement:
1935 Ford Advertisement
History of the 51 Year Old California
Profilograph and Specification
California Statewide Roughness
Survey (1956)
Tested 15 Concrete
Sections
Tested 11 Asphalt
Sections
Jury Evaluation
Established
7 inches/mile
Developed
0.2” Blanking Band
1957-1960 25 ft Profilograph
2
Profilograph Specification Development
Profile Ride Index
Estimates Smoothness
(Jury)
Improves Construction
Practice
Blanking Band
Eliminates Small Stuff
Bump Grind
Determines Grinding
Strategy
How Do We Get Profilograph Ride
Index?
= Measures Road
Features
+
Gain
2.0
Profilograph
1.5
Profiler
1.0
= Modifies Road
Features
0.5
0
1
10
100
Wavelength (ft)
1000
+
Factors Affecting Profilograph Results
Operator Variability
Path
Speed
Gain
2.0
Trace Reduction
Manual
Automated
Equipment Calibration
The Profilograph Design
Profilograph
1.5
Profiler
1.0
0.5
0
1
10
100
Wavelength (ft)
1000
Remember…
“While the profile index appears to be reasonably satisfactory for use in
specifications, it fails to differentiate between bumps or irregularities of
different shape and of different length and this numerical expression does not
adequately emphasize the annoyance in terms of riding qualities generated by
badly faulted pavement for example. A somewhat more elaborate system
of deriving a numerical index will be necessary if it becomes important
to assign numbers to existing highways or airfields…”
Francis Hveem 1960 regarding
California profilograph
Gain
2.0
Profilograph
1.5
Profiler
1.0
= Relevance to 19401950 Vehicle Ride
Comfort (Jury)
A Half a Century Later…
We are Still Seeking Relevance in Profile Measurement
First attempts were to modify the blanking band
(0.1 in. and 0.0 in.)
Second attempt is to measure the PrI and Convert
to IRI as the roughness statistic
Third attempt is to measure actual road profile and
use IRI statistic
0.5
0
1
10
100
Wavelength (ft)
1000
Factors Affecting Roughness OR
Why PrI and IRI Measure Different
Things
Subjective ride quality is best correlated to
wavelengths between 1.6 ft to 8 ft
(NCHRP 275)
Greatest dynamic forces applied to pavements
by wavelengths from 2 ft to 32 ft
3
Correlating PrI(0) to PrI (0.2)
Correlating PrI to IRI
Use of Profile For Ride Comfort
Evaluation
Inertial Profile Measurement Equipment
Insert Photo of One of your Light Weights
1. Reference elevation = instrument height
2. Height relative
to reference = rod
longitudinal
reference point
3. Longitudinal distance
measured with tape or laser
Computer
3. Speed/Distance Measuring
System
1. Inertial Reference
Accelerometer: A
2. Height Relative to Reference
(laser, infrared, or optical transducer)
Factors Affecting Profiler Measurement
Equipment Calibration
Vehicle Path
Sensor Type and
Foot Print Size
Gain
2.0
Profilograph
1.5
Profiler
1.0
0.5
Filtering Techniques
0
1
10
100
Wavelength (ft)
Right Elevation Profile (mm)
40
20
0
-20
-40
complete profile
high-pass filtered (91 m)
0
50
100
1000
Profile-Based Specifications:
is IRI?
What
It is a road roughness measurement (ride comfort)
IRI was originally developed as a correlation
standard for response-type systems.
The Index was tuned to maximize correlation with
a large collection of response type systems.
Its the best representation of what a driver
experiences when driving an automobile over
the roadway
150
Distance (m)
4
International Roughness Index
Profile + Filter = Result (IRI)
ROAD
Elevation (in)
.6
0
-.6
3400
3600
3800
4000
Distance (ft)
4200
4
Roughness Profile (in/mi)
60
500-ft Baselength
+
IRI Response
2
4400
=
CAR
Roughness
Statistic
50
40
30
1.5
20
0
1000
2000
3000
Distance (ft)
4000
5000
1
.5
0
1
Footprint/Sensor Issues
10
Wavelength (ft)
100
ACPA IRI Repeatability Study--2005
Results are affected by how laser(s) interact with
texture
Grinding
Trans.
Tining
Long.
Tining
Drag
Profiler A
Profiler B
Profiler C
Profiler D
Profiler E
Good
Range in IRI Measurement for
Diamond Ground Surface
Development of a Transition Plan
and Team
Dynatest
MarkA
IV
Profiler
Ames
HS/TriODS
Profiler
B
P fil C
Profiler
Ames LW/RoLine
Ames
LW/TriODS
Profiler
D
SurPro 2000
Profiler
E
0
10
20
30
IRI (in/mi)
40
Excellent
50
60
Should Include/Involve Agency and Contractors
Should Address Equipment and Measurement
Procedures
Should Address IRI Specifications and
incentive/disincentive issues
Should be Based on Current
Practice/expectations and Improvement
Transitioned in the Future Over Time
5
Equipment Considerations
Will the Equipment be Used Only for Construction
Control and Payment or Will it be used in the PMS
and Provide a Closed Loop Feedback Process for
p
the Department
Who Will Operate/maintain Equipment
How, When and Where Will Equipment and
Operators be Certified
Specifications for Equipment Purchase/Suitability
Specification Considerations (Cont.)
Center Window
Longitudinal Referencing
Must Grind Locations and Criteria
Wh iis ttesting
When
ti tto bbe conducted
d t d (ti
(time))
Who Will Conduct Testing and Analyze
Will ProVAL file format be required
Applicable AASHTO Standards
PP 50 Standard Practice for Operating Inertial
Profilers and Evaluating Pavement Profiles
MP 17 Standard Practice for Pavement Ride
Quality When Measured Using Inertial Profiling
Systems
MP11 Standard Equipment Specification for an
Inertial Profiler
PP49 Standard Practice for Certification of
Inertial Profiling Systems
Specification Considerations
Need to Establish the Current Standard of
Practice in the Industry on Ride Quality
Need to Decide on Form of Specification:
Incentive?
Disincentive?
Rejection
Continuous versus step function
Measurement Interval
Implementation Process
Transition Team Recommends Pilot Specification
and Equipment
Use AASHTO Specifications for Development
Use ProVAL as Analysis Tool and Procedure in
Specification
Implement Shadow Specification on Active
Projects Along with Traditional Specification
(Pay) for One Paving Season.
Results Evaluated by Transition Team.
Modifications Made if Necessary
ProVAL: Profile Viewing and Analysis
Reliability: ProVAL is a reliable tool for pavement profile analysis. The functions
in ProVAL have been validated by thousands of users around the world.
Cost Savings: Save on the development, maintenance and support costs of inhouse profile analysis tools. Take advantage of the efficient functions in ProVAL
to reduce evaluation time and costs and boost profit from one-of-a-kind tools
such as the grinding simulation.
simulation
Analyze and View: ProVAL allows you to view and analyze pavement profiles
from common profile data formats used by both contractor and agency alike.
Objectivity: ProVAL is sponsored by the FHWA and LTPP with continual
improvement and support. No bias towards any specific vendors.
Security: The ProVAL native data format (Pavement Profile Format or PPF)
makes it more secure than most of other profile data formats. Any manipulation
on a ProVAL data file will be recorded in its "History" and can be viewed.
6
ProVAL 3.0 Is Almost Here
Questions?
www.roadprofile.com
Why are We Interested in Surface
Characteristics?
Vehicle Control
Safety
Driver Security
Delineation
Ride Comfort
Smoothness
Dynamic Loading (Commerce)
Mobility
Quickly without Delay
Construction Delays
Maintenance Delays
Economics
Initial Cost
LCCA Cost
Fuel Efficiency
Durability
Consistent Properties
Ride
Friction
Acoustic
Noise Comfort
Neighborhood
In-Vehicle
7