SLIDE 1
The C-LTPP project
- The C-LTPP Project includes 24 test sites constructed between 1989 and 1991.
- Each site has 2 to 4 adjacent test sections for a total of 65 test sections.
Location and identification of C-SHRP LTPP test sites.
DETECTING LOCALIZED ROUGHNESS USING DYNAMIC SEGMENTATION By Amin - - PowerPoint PPT Presentation
DETECTING LOCALIZED ROUGHNESS USING DYNAMIC SEGMENTATION By Amin - - PowerPoint PPT Presentation
DETECTING LOCALIZED ROUGHNESS USING DYNAMIC SEGMENTATION By Amin El Gendy & Ahmed Shalaby Department of Civil Engineering University of Manitoba The C-LTPP project The C-LTPP Project includes 24 test sites constructed between 1989 and
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SLIDE 3
C-LTPP profile data
- Profile measurements taken manually with a dipstick on annual basis.
- Dipstick foot spacing is 300 mm for most of the sections.
- The survey closure error was redistributed over all the measurements
recorded.
5*30 m OWP IWP OWP-IWP IWP-OWP Start Point
Schematic for the dipstick profiling process
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Objectives
To develop guidelines for analyzing the measurement of
longitudinal pavement profile using two dynamic segmentation methods;
To demonstrate the benefits of refining the monitoring of
pavement conditions; and
To Propose a model for estimating the required interval
for reporting roughness profiles.
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1 2 3 4 5 20 40 60 80 100 120 140 Station [m] IRI [m/km]
- Min. IRI=1.36
- Max. IRI=3.82
Average IRI=2.45 Roughness Profile IRI Range
Roughness Profile
The roughness profile for the OWP of the test site 810404 (prior to overlay 09/06/1990)
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Significance of Roughness Profile Segmentation
0.05 0.1 0.15 0.2 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 IRI range [m/km] Percentage of Frequency The frequency distribution of IRI range (1332 section profiles)
12 out of 1332 profiles have an IRI range smaller than 1.0mm/m.
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The cumulative difference approach (CDA)
(a) Pavement Response, ri X1 X3 X2 (b) Cumulative Area, Ax X1 X3 X2 (c) Cumulative Difference, Zx X1 X3 X2 X
_ x x x
A A Z − =
_ x
A
x
A
(-) (+) (-)
- +
Border Border r1 r2 r3 X X X
(a) Response (b) Cumulative Area (c) Cumulative Differences
The cumulative difference approach
SLIDE 8
The absolute difference approach (ADA)
Segment length Average response X Response range xi xd ri rd
d i i
r r Z − =
The absolute difference approach
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Illustrative Example
(a) ADA Segmentation (b) CDA Segmentation (c) Cumulative Area (d) Cumulative Differences
Segmentation Example
Pavement Response, ri Segment Length Cumulative Area, Ax Segment Length Cumulative Difference, Zx Segment Length (-) (+) (-)
- +
Border Border CDA Segments Pavement response Pavement Response, ri Segment Length
ADA Segments Pavement response Response range
r1 r2 r3 r1 r2 r3
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is the response ri at xi for segment 1. is the response rj at xj for segment 2. xi is any distance within segment 1. xj is any distance within segment 2. rrange is the specified target response range
Combining Segments
j i Range j i
x x all for r r r ,
2 1
≤ −
1 i
r
2 j
r
Each two adjacent segments will be combined into one segment if the difference between the maximum and minimum does not exceed the target range according to the following:
Where;
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Statistical Comparison
TABLE 1 General Statistical Summary for Segment Lengths (m), CDA Approach
9315 9684 10505 12180 15819 24466 Count 835.52 760.57 648.83 478.43 271.26 92.22 Sample Variance 28.90 27.58 25.47 21.87 16.47 9.60 Standard Deviation 0.30 0.28 0.25 0.20 0.13 0.06 Standard Error 18.90 18.17 16.73 14.39 11.01 7.01 Mean of segment lengths 0.7 0.6 0.5 0.4 0.3 0.2 IRI Range (m/km) Statistic
TABLE 2 General Statistical Summary for Segment Lengths (m), ADA Approach
12404 12568 13414 15705 21001 34328 Count 712.56 668.95 572.67 397.18 205.95 64.09 Sample Variance 26.69 25.86 23.93 19.93 14.35 8.01 Standard Deviation 0.24 0.23 0.21 0.16 0.10 0.04 Standard Error 14.12 13.93 13.04 11.09 8.22 4.91 Mean of segment lengths 0.7 0.6 0.5 0.4 0.3 0.2 IRI Range (m/km) Statistic
SLIDE 12
Segmented Profiles
0.6 0.8 1 1.2 1.4 27 32 37 42 47 Station [m] IRI [m/km] Roughness Profile CDA Segmentation ADA Segmentation
The roughness profile corresponded with segmentation data for test site 810404
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Relationship between segment length and IRI range
4 8 12 16 20 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 IRI range [m/km] Average of Segment lengths [m] CDA segmentation ADA segmentation
Relationship between segment length and IRI range
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Reporting Interval Model
4 8 12 16 20 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 IRI range [m/km] Reporting interval [m] Average of CDA and ADA Logarithmic Linear Quadratic
0.09 0.99 L= -42.5 IRI2
range + 59.4 IRIrange - 4.3
Quadratic 0.54 0.98 L= 8.8 loge(IRIrange) + 20.4 Logarithmic 1.29 0.92 L= 21.2 IRIrange + 3.1 Linear SE R2 Equation Model
Comparison of three models for reporting interval. TABLE 3 Models for Correlating IRI Range (m/km) and Reporting Interval (m)
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Conclusions and Recommendations
A sample of 1332 roughness profiles has
been analyzed to evaluate the effect of localization of roughness values.
Two methods for segmenting profiles were
used.
ADA method is recommended when IRI
range is required because CDA may provide some segments that have IRI range
- utside the required range.
SLIDE 16
Conclusions and Recommendations (Cont.)
Segments were combined based on
different values of IRI range starting from 0.2 m/km to 0.7 m/km.
The relationship between IRI range and
segment length is estimated.
A quadratic mathematical model is
introduced to estimate the required interval for reporting roughness profiles.
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