1、Standard Practice for Determining Pavement Deformation Parameters and Cross Slope from Collected Transverse Profiles AASHTO Designation: PP 69-161 Release: Group 1 (April 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C
2、. 20001 TS-5a PP 69-1 AASHTO Standard Practice for Determining Pavement Deformation Parameters and Cross Slope from Collected Transverse Profiles AASHTO Designation: PP 69-161Release: Group 1 (April 2016) 1. SCOPE 1.1. This practice outlines a method for deriving pavement deformation parameters such
3、 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 can be adequately validated to meet the functionality stipulated herein i
4、s 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 will typically be processed utilizing a collection of algorithms in a
5、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 determine the applicability of regulatory limitations related to and pr
6、ior to its use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: PP 70, Collecting the Transverse Pavement Profile 3. TERMINOLOGY 3.1. Definitions: 3.1.1. cross slopethe average transverse slope of the pavement surface expressed in percent. 3.1.2. inside wheel patha longitudinal strip of pavement 1.0 m
7、 (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, in the absence of markings, an equivalent portion of the pavement surf
8、ace. 3.1.4. outside lane edgea line 100 mm (4 in.) beyond the outside 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. 2016 by the American Association of State Highway and Transportation
9、Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a PP 69-2 AASHTO 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 centerline of the lane in the direction of travel. 3.1.6. percent deformat
10、ionthe 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 surface with a depth of at least 2 mm (0.080 in.), a width of at least
11、 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 pavement surface from a horizontal reference perpendicular to the lane
12、 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 a location at the middle of the road on one-lane roads. 4. SIGNIFICAN
13、CE 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 analysis. 4.2. This method reflects a balance between extreme calculation c
14、omplexity 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. Likewise, there will be unusual transverse contours that will not calc
15、ulate 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 PP 70. Other collection protocols may be followed if the data requirements of PP 70 are met or exceeded. 6. DATA REDUCTION 6.1. A
16、ll 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 transverse profile data should be processed to first remove outlier values
17、, 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 established to determine the lane location and width within each profile and
18、 correlate this information with the profile data. 6.4. Establish the 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. 2016 by the American Association of State Highway and Transpo
19、rtation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a PP 69-3 AASHTO 6.4.2. Determine the average elevation for each half lane. 6.4.3. The percent cross slope is the difference in the average elevations divided by one-half the lane width multiplied by 100. 6.5. C
20、alculate 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 straight-line distance between the two end points. 6.5.2. Add the secti
21、on 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. 6.5.4. Potentially useful portions of the profile for deformation
22、 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. Determine Five Key Data Zones in the Lane: 6.6.1. Define the lane edg
23、es 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 elevation is the average of the elevation data points measured in the ce
24、nter 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 path. Its location is the midpoint of the selected points. 6.6.2.3
25、. 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 wheel path elevationIts elevation is the average of the elevation
26、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 the outside pavement edge. Its location is 50 mm (2 in.) from the o
27、utside pavement edge. 6.7. Calculate Rut Depth: 6.7.1. Convert the percent cross slope to an angle. 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. 2016 by the American Association of State Highway an
28、d Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a PP 69-4 AASHTO 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 average of spots 2 and 4. 6.7.5. Normal Rut Depth Calculation: 6.7
29、.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 value of spot 4 is the depth of the outside rut. 6.7.6. Center Dep
30、ression 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 the step in Section 6.7.5.1, scan the profile in both directions
31、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 elevation values between the edges and multiplying the sum by the
32、 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 Entrapment Depth: 6.9.1. Further smooth the profile with a 200-mm (8-i
33、n.) 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 a lower filtered elevation than any previous filtered elevation
34、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 the three (the lip) and subtract the lowest filtered elevation prev
35、iously 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 profile is completed. (It is quite likely to have multiple water en
36、trapment 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 spot 3 in a similar fashion. 7. DATA REPORTING 7.1. For network
37、collection, each summary section shall be 10 m (33 ft) and have reported: 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a PP 69-5 AASHTO 7.1.1. The average cross slope percentage; 7.1.2. The avera
38、ge 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 have reported: 7.2.1. The items in Section 7.1 over the shorter sum
39、mary 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. DATA INTERPRETATION 8.1. The agency is free to utilize the report
40、ed 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, natural variation in the data will cause dramatic shifts in results. S
41、uch 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. Generally, the agency should follow the manufacturers recommendat
42、ions 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 profiles collected as part of the equipment verification process
43、. 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; cross slope; pavement management; rut. 11. REFERENCES 11.1. AS
44、TM E1656/E1656M, Standard Guide for Classification of Automated Pavement Condition Survey Equipment. 11.2. FHWA. Distress Identification Manual for the Long-Term Pavement Performance Program, FHWA Report RD-03-031. 1This provisional standard was first published in 2010. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
