1、Standard Practice for Determining Pavement Deformation Parameters and Cross Slope from Collected Transverse Profiles AASHTO Designation: R 87-181Technical Section 5a: Pavement Measurement Release: Group 1 (April) American Association of State Highway and Transportation Officials 444 North Capitol St
2、reet N.W., Suite 249 Washington, D.C. 20001 TS-5a R 87-1 AASHTO Standard Practice for Determining Pavement Deformation Parameters and Cross Slope from Collected Transverse Profiles AASHTO Designation: R 87-181Technical Section 5a: Pavement MeasurementRelease: Group 1 (April) 1. SCOPE 1.1. This pract
3、ice outlines a method for deriving pavement deformation parameters such as rut depth and cross slope in pavement surfaces utilizing a transverse profile. Detailed specifications are not included for equipment or software used to make the calculations. According to this standard, any approach that ca
4、n be adequately validated to meet the functionality stipulated herein is considered acceptable. The goal is to achieve a significant level of standardization that will contribute to the production of consistent pavement condition estimates without unduly restricting innovative methods. 1.2. The data
5、 will typically be processed utilizing a collection of algorithms in a computer. 1.3. This practice does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and
6、determine the applicability of regulatory limitations related to and prior to its use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: R 88, Collecting the Transverse Pavement Profile 3. TERMINOLOGY 3.1. Definitions: 3.1.1. cross slopethe average transverse slope of the pavement surface expressed in p
7、ercent. 3.1.2. inside wheel patha longitudinal strip of pavement 1.0 m (39 in.) wide and centered 0.875 m (35 in.) to the left of the centerline of the lane in the direction of travel. 3.1.3. lanethe traveled surface between the inside edge of the left pavement marking and the outside lane edge or,
8、in the absence of markings, an equivalent portion of the pavement surface. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 87-2 AASHTO 3.1.4. outside lane edgea line 100 mm (4 in.) beyond the ou
9、tside limit of the edge pavement marking. In the absence of an edge pavement marking, it is a user-defined distance from the left edge marking or pavement centerline. 3.1.5. outside wheel patha longitudinal strip of pavement 1.0 m (39 in.) wide and centered 0.875 m (35 in.) to the right of the cente
10、rline of the lane in the direction of travel. 3.1.6. percent deformationthe difference between the straight-line length and the profile length of a section of pavement divided by the straight-line length multiplied by 100. 3.1.7. ruta broad longitudinal depression in the wheel path of the pavement s
11、urface with a depth of at least 2 mm (0.080 in.), a width of at least 0.3 m (1.0 ft), and with a longitudinal length of at least 30 m (100 ft). 3.1.8. summary sectiona longitudinal length of a pavement lane over which the data are summarized. 3.1.9. transverse profilethe vertical deviations of the p
12、avement surface from a horizontal reference perpendicular to the lane direction. 3.1.10. lane centera location halfway between the inside edges of the pavement edge markings. If no markings are present, a location 22 percent of the total pavement width from the pavement middle on two-lane roads and
13、a location at the middle of the road on one-lane roads. 4. SIGNIFICANCE AND USE 4.1. The method outlines a set of procedures to calculate several measures of pavement deformation related to the transverse profile. The adoption of these procedures will help produce consistent data for pavement analys
14、is. 4.2. This method reflects a balance between extreme calculation complexity and resultant accuracy. It is not expected to give the correct values for each individual deformation condition but to provide data that, taken in aggregate, will provide an accurate picture of the deformation involved. L
15、ikewise, there will be unusual transverse contours that will not calculate correctly. It is expected, however, that their occurrence will be minimal. 5. DATA COLLECTION 5.1. Typically, the transverse profile is to be collected according to R 88. Other collection protocols may be followed if the data
16、 requirements of R 88 are met or exceeded. 6. DATA REDUCTION 6.1. All calculations are made for each transverse profile reported. For network-level data, the processed profiles should not be more than 3 m (10 ft) apart and for project level, no farther apart than 0.5 m (1.5 ft). 6.2. The raw transve
17、rse profile data should be processed to first remove outlier values, and then to smooth the data. An example of smoothing involves the application of an approximately 50-mm (2-in.) moving average filter. The resultant profile is used for all subsequent calculations. 6.3. A system should be establish
18、ed to determine the lane location and width within each profile and correlate this information with the profile data. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 87-3 AASHTO 6.4. Establish t
19、he Cross Slope: 6.4.1. Utilizing the lane width and location from Section 6.3, determine the middle of the lane and locate the associated middle data point in the profile. 6.4.2. Determine the average elevation for each half lane. 6.4.3. The percent cross slope is the difference in the average eleva
20、tions divided by one-half the lane width multiplied by 100. 6.5. Calculate Percent Deformations: 6.5.1. Establish end points for the portion of the profile under consideration (see Section 3.3) by averaging the three closest elevation points to the selected end point location and calculate the strai
21、ght-line distance between the two end points. 6.5.2. Add the section length of all the segments between the two end points to approximate the actual profile length. 6.5.3. Subtract the straight-line length from the profile length and divide the result by the straight-line length and multiply by 100.
22、 6.5.4. Potentially useful portions of the profile for deformation reporting would be: total lane, inside half, outside half, and middle third. 6.5.5. Deformation criteria can be used to select profiles for more detailed analysis, such as water entrapment or depression cross-sectional area. 6.6. Det
23、ermine Five Key Data Zones in the Lane: 6.6.1. Define the lane edges utilizing lane pavement marks, construction history, or other means, if not already defined during collection. 6.6.2. Locate and determine values at five spots across the lane. 6.6.2.1. Spot 1 is the lane center elevationIts elevat
24、ion is the average of the elevation data points measured in the center 75 mm (3 in.) of the pavement lane. Its location is the center of the lane. 6.6.2.2. Spot 2 is the inside wheel path elevationIts elevation is the average of the elevation data points in the lowest 10 percent of the inside wheel
25、path. Its location is the midpoint of the selected points. 6.6.2.3. Spot 3 is the inside edge elevationIts elevation is the average of the elevation data points within 100 mm (4 in.) of the inside pavement edge. Its location is 50 mm (2 in.) from the inside lane edge. 6.6.2.4. Spot 4 is the outside
26、wheel path elevationIts elevation is the average of the elevation data points in the lowest 10 percent of the wheel path. Its location is the midpoint of the selected points. 6.6.2.5. Spot 5 is the shoulder elevationIts elevation is the average of the elevation data points within 100 mm (4 in.) of t
27、he outside pavement edge. Its location is 50 mm (2 in.) from the outside pavement edge. 6.7. Calculate Rut Depth: 6.7.1. Convert the percent cross slope to an angle. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of app
28、licable law.TS-5a R 87-4 AASHTO 6.7.2. Rotate the profile about spot 3 by the angle above, thus leveling the profile. 6.7.3. Shift the profile so that the value of spot 3 is zero. 6.7.4. Proceed to center depression rut depth calculation if the value of spot 1 is more than 5 mm (0.2 in.) below the a
29、verage of spots 2 and 4. 6.7.5. Normal Rut Depth Calculation: 6.7.5.1. Rotate the profile about spot 3 until spot 1 is 0. The revised absolute value of spot 2 is the depth of the inside rut. 6.7.5.2. Rotate the lane half between spots 1 and 5 about spot 1 until spot 5 is zero. The revised absolute v
30、alue of spot 4 is the depth of the outside rut. 6.7.6. Center Depression Rut Depth Calculation: 6.7.6.1. Rotate the profile about spot 3 until spot 5 is zero. The revised absolute value of spot 1 is the depth of the center depression. 6.8. Calculate Rut Cross-Sectional Area: 6.8.1. After completing
31、the step in Section 6.7.5.1, scan the profile in both directions from spot 2 until three values equal to or greater than zero are reached, and record the location of the first one encountered in each direction. These locations are the rut edges. 6.8.2. The area can be approximated by adding all the
32、elevation values between the edges and multiplying the sum by the data point interval. 6.8.3. Repeat the same process around spot 4 after completing the step in Section 6.7.5.2. 6.8.4. For center-depressed pavements, the same process can be applied around spot 1. 6.9. Calculate Potential Water Entra
33、pment Depth: 6.9.1. Further smooth the profile with a 200-mm (8-in.) moving average filter. 6.9.2. For positive cross slope (spot 5 filtered elevation less than spot 3) and zero cross slopes, scan the profile from spot 3 toward spot 5 for locations in which a filtered elevation is not equal to or at
34、 a lower filtered elevation than any previous filtered elevation plus 2 mm (0.08 in.). 6.9.3. Should such a point be encountered, continue scanning until three sequential filtered elevations that are lower than their predecessor are encountered. Take the filtered elevation at the highest point of th
35、e three (the lip) and subtract the lowest filtered elevation previously encountered. The difference is the water entrapment depth of the discovered depression. The location of the lowest point should also be recorded. 6.9.4. Beginning at the lip found in Section 6.9.3, continue scanning until the pr
36、ofile is completed. (It is quite likely to have multiple water entrapment depths encountered.) They can be sorted by location to determine their relationship to the wheel paths. 6.9.5. For negative cross slopes (spot 3 filtered elevation less than spot 5), the profiles are scanned from spot 5 toward
37、 spot 3 in a similar fashion. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 87-5 AASHTO 7. DATA REPORTING 7.1. For network collection, each summary section shall be 10 m (33 ft) and have repor
38、ted: 7.1.1. The average cross slope percentage; 7.1.2. The average rut depth for each wheel path (normal or center) in millimeters (inches); and 7.1.3. The maximum rut depth for each wheel path in millimeters (inches). 7.2. For project level activity, each summary section shall be 2 m (7 ft) and hav
39、e reported: 7.2.1. The items in Section 7.1 over the shorter summary section of the project level collection; 7.2.2. The water entrapment depth for each third of the lane width averaged over the profiles in the section; and 7.2.3. Average rut cross-sectional area in square meters (square feet). 8. D
40、ATA INTERPRETATION 8.1. The agency is free to utilize the reported data as best fits its pavement management needs. 8.2. Agencies are alerted that dividing the scalar depth and percentage indexes into level categories or bins can result in erratic results. When values are near the bin limits, natura
41、l variation in the data will cause dramatic shifts in results. Such converting can be useful, however, for general comparison to previously collected data in which bin limits were used. 9. SYSTEM VALIDATION 9.1. The process of checking the performance of the analysis process is left to the agency. G
42、enerally, the agency should follow the manufacturers recommendations for verifying its performance. The following considerations should be included in any program. 9.1.1. Multiple transverse profiles that reflect the conditions encountered in the real data collection world. These should include the
43、profiles collected as part of the equipment verification process. 9.1.2. It is planned that a standard set of profiles will eventually be developed to verify the performance and highlight the limitations of the processing method. 10. KEYWORDS 10.1. Asphalt pavement surface; automated data collection
44、; concrete pavement surface; cross slope; pavement management; rut. 11. REFERENCES 11.1. ASTM E1656/E1656M, Standard Guide for Classification of Automated Pavement Condition Survey Equipment. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplica
45、tion is a violation of applicable law.TS-5a R 87-6 AASHTO 11.2. FHWA. Distress Identification Manual for the Long-Term Pavement Performance Program, FHWA Report RD-03-031. 1Formerly AASHTO Provisional Standard PP 69. First published as a full standard in 2018. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
