1、Standard Practice for Operating Inertial Profiling Systems AASHTO Designation: R 57-141American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-5a R 57-1 AASHTO Standard Practice for Operating Inertial Profiling Systems AAS
2、HTO Designation: R 57-1411. SCOPE 1.1. This practice describes the procedure for operating and verifying the calibration of an inertial profiling system. This practice is meant to be performed as a quality control/quality assurance (QC/QA) test for use with the appropriate smoothness specification f
3、or paving operations and for network-level data collection. It is not meant to be required as a QA procedure to monitor daily paving operations; however, it is recommended when inertial profiling systems are used for QC testing. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 328, Inertial Profiler
4、 R 56, Certification of Inertial Profiling Systems 2.2. ASTM Standards: E867, Standard Terminology Relating to Vehicle-Pavement Systems E1926, Standard Practice for Computing International Roughness Index of Roads from Longitudinal Profile Measurements E2560, Standard Specification for Data Format f
5、or Pavement Profile 2.3. Other Document: Sayers, M. W. “On the Calculation of International Roughness Index from Longitudinal Road Profile.” Transportation Research Record 1501. Transportation Research Board, National Research Council, Washington, DC, 1995, pp. 112. 3. TERMINOLOGY 3.1. Definitions:
6、3.1.1. International Roughness Index (IRI)a statistic used to determine the amount of roughness in a measured longitudinal profile. The IRI is computed from a single longitudinal profile using a quarter-car simulation at 50 mph (Sayers 1995). Computer programs to calculate the IRI from a longitudina
7、l profile are referenced in ASTM E1926. 3.1.2. longitudinal profilethe vertical deviations of the pavement surface taken along a line in the direction of travel referenced to a horizontal datum. 3.1.3. roughnessaccording to ASTM E867, the deviation of a surface from a true planar surface with charac
8、teristic dimensions that affects vehicle dynamics, ride quality, dynamic loads, and drainage. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 57-2 AASHTO 4. SIGNIFICANCE AND USE 4.1. This practi
9、ce outlines standard procedures for operating inertial profiling systems for project-level QC/QA determinations and for network-level data collection and analyses. 5. EQUIPMENT 5.1. Minimum RequirementsThe inertial profiling system must meet all requirements and specifications found in M 328 and mus
10、t be currently certified in accordance with R 56. Note 1For consistent pavement profile determination, maintain air pressure in the tires of the host vehicle according to the manufacturers specification. The host vehicle and all system components will be in good repair and proven to be within the ma
11、nufacturers specifications. The operator of the inertial profiler shall have all tools and components necessary to adjust and operate the inertial profiler according to the manufacturers instructions. 5.2. Repair, Adjustment, and Upgrade of Inertial Profilers: 5.2.1. Major component repairs or repla
12、cement to an inertial profiler that would require the recertification of the equipment include, but are not limited to, the following: The accelerometer and its associated hardware; The noncontact height sensor and its associated hardware; Any printed circuit board necessary for the collection of ra
13、w sensor data or the processing of the inertial profiles; Change of host vehicle in the case of permanently mounted equipment; or Major repairs to the host vehicle. 5.2.2. The operator of the inertial profiler will be allowed to make minor adjustments to the equipment without having to complete the
14、recertification process as long as the adjustments allow the equipment to fulfill the verification of calibration process in Section 5.3. Minor adjustments to the system include, but are not limited to, the following: Inspecting, resoldering, or replacing connectors; Cleaning components, normal adju
15、stments to power supply voltage levels as required by the manufacturer; Setting software parameters and/or scale factors as required by the manufacturer in a routine calibration procedure; or Mounting on different suitable host vehicle(s) in the case of portable equipment. 5.3. Verifying Calibration
16、The following verification procedure is required for an inertial profiler used for QA testing of smoothness of new construction and network-level profiling, and is recommended when an inertial profiler is to be used as a QC instrument on a daily basis. 5.3.1. Standards: 5.3.1.1. Longitudinal: 5.3.1.
17、1.1. The longitudinal verification standard shall be a straight and level roadway test section of at least 528 ft in length with sufficient lead-in distance for the vehicle to attain a constant speed before the start of the test section and a safe stopping distance. 5.3.1.1.2. Measure this length ac
18、curately to within 0.05 percent using a measurement tape since the distance to be measured is the travel length the wheels encounter. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 57-3 AASHTO
19、5.3.1.2. Vertical: 5.3.1.2.1. The vertical measurement standard shall be flat plates or blocks of known thickness and low thermal expansion. 5.3.1.2.2. Mark the blocks with the known thickness. Certify the block thickness accurate to within 0.001 in. As a minimum, test a smooth base plate and both a
20、 1-in. and a 2-in. gauge block. 5.3.2. Procedure: 5.3.2.1. Frequency of Verifying Calibration: 5.3.2.1.1. For QC and QA testing of smoothness of new construction, perform the longitudinal and vertical verification of calibration of the inertial profiler prior to use on each paving project in accorda
21、nce with the manufacturers recommendation and at such times as the Owner-Agency determines that verification is necessary. For network-level profiling, it is recommended that the longitudinal verification of calibration and the block check for verification of vertical calibration be performed at lea
22、st monthly, and the bounce test for verification of vertical calibration be performed daily. 5.3.2.1.2. Check the cold tire air pressure on the wheels of the host vehicle at least daily and maintain according to the manufacturers recommendations. 5.3.2.2. Longitudinal Verification of Calibration: 5.
23、3.2.2.1. Perform the longitudinal verification of calibration by navigating the inertial profiler over a measured test section of at least 528 ft. 5.3.2.2.2. The inertial profilers distance measuring subsystem, after tire and electronic warm-up in accordance with the manufacturers recommendations, m
24、ust measure the length of the test section to within 0.15 percent of its actual length. 5.3.2.2.3. If the specified criterion is not met, adjust the inertial profilers distance measurement subsystem according to the manufacturers guidelines as needed. 5.3.2.2.4. Failure to meet the specified toleran
25、ce, after attempts to adjust have been performed, will require recalibration, and then reverification as described in Section 5.3.2.2. 5.3.2.3. Vertical Verification of CalibrationVertical verification of calibration consists of performing two tests, the block test and the bounce test. 5.3.2.3.1. Bl
26、ock TestVertical height sensor check tests shall be performed in accordance with the manufacturers recommended procedures. In the absence of manufacturers procedures, perform the block test as described in Section 5.3.2.3.1.Vertical height sensor check tests are run after the profiler has reached op
27、erational stability as specified by the manufacturer. This test will be conducted with the inertial profiler on a relatively flat and level area. Its purpose is to check the height measurements (in inches or millimeters) from the height sensor(s) of the test vehicle using blocks of known heights. Du
28、ring the test, do not lean on the profiler or cause it to move in any way. Under windy conditions, it may be necessary to perform this test indoors. The test procedure consists of the following steps: Position a smooth base plate under the height sensor of the profiler and allow the system to take h
29、eight measurements. Position a 0.25-in. block underneath the height sensor on top of the base plate and allow the system to take height measurements. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5
30、a R 57-4 AASHTO Carefully remove the 0.25-in. block from the base plate and replace it with a 0.50-in. block. Make another set of height measurements. Carefully replace the 0.50-in. block with a 1.00-in. block and take another set of height measurements. Finally, carefully replace the 1.00-in. block
31、 with a 2.00-in. block and take the last set of height measurements. As a minimum, test a base plate and both the 1- and 2-in. measurement blocks. If the equipment fails the minimum test, then perform the full range of tests to determine system linearity problems, stand-off problems, or complete sys
32、tem failure. The owners of the profiler must furnish their own base plate and gauge blocks. Measure the thickness of the gauge blocks at three different positions on each side of the block with a device capable of measuring to the nearest 0.001 in. For each block, an average thickness shall be deter
33、mined from the measurements made, which shall be used in checking the height sensors as described in this test. The average thickness shall be marked on each gauge block. The operator of the profiler should tabulate the measurements and record them in a calibration log. Determine the difference betw
34、een each measurement on a gauge block and the average of the ten measurements on the base plate to get the thickness of the gauge block as measured by the height sensor. Repeat this calculation for each gauge block. Determine the absolute values of the differences between the computed block thicknes
35、s and the known average block thickness. The absolute difference should be less than or equal to 0.01 in. for each gauge block. 5.3.2.3.2. Bounce TestTo perform the bounce test, position the host vehicle on a surface as flat and level as possible. Power the system and ensure that the profiler has re
36、ached operational stability as specified by the manufacturer. Center a thin, smooth, flat, nonglossy material plate under each sensor. Using the equipments normal data collection software, initiate a data collection run using a simulated travel speed at the midpoint of the manufacturers recommended
37、data collection speed range. (The only difference between a bounce test and a normal data collection run is that there is an artificial longitudinal travel signal supplied and the vehicle is not actually traveling along the road. The bounce test utilizes the same data collection software and routine
38、s used during normal data collection.) The bounce test will require a profile collection run with a minimum simulated travel distance of 2184 ft. Allow the profiler to collect a minimum of 828 ft of static profile with the host vehicle as motionless as possible. Next, the sensor(s) should be moved v
39、ertically for a total displacement of approximately 1 to 2 in. (a yardstick may be helpful until the operator gets used to the procedure) keeping the sensors as close to perpendicular to the surface as possible during this movement. This movement must continue until a minimum of 528 ft of simulated
40、longitudinal distance has been covered. The typical method for full-size, high-speed host vehicles is to push the mounting system (bumper) down an inch or so and let the vehicle suspension rebound to create the total vertical travel of 1 to 2 in. The typical method for lightweight, slow-speed host v
41、ehicles is to stand toward the center of the vehicle platform and hop up and down such that all four corners of the vehicle suspension travel approximately 1 to 2 in. vertically. After a minimum of 528 ft of bounce profile is collected, allow the profiler to collect an additional minimum of 828 ft o
42、f static profile. The profiles shall then be saved and analyzed using the latest version of ProVAL software to compute the continuous IRI with a 528-ft base length for each profile collected. When reviewing the analysis results, ignore the first and last 300 ft of the profile as it is lead-in and le
43、ad-out distance. Ensure the remaining static portions result in an IRI of less than 3 in./mile and the bounce portion IRI is less than 8 in./mile. The two static IRI portions should be about the same. This requirement applies to each sensor in the profiler. See Appendix X1 for further details concer
44、ning the bounce test. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a R 57-5 AASHTO Note 2The Profile Viewer and Analysis (ProVAL) software program developed for the Federal Highway Administration
45、, which can be used to import, display, and analyze the characteristics of pavement profiles from many different sources, is available at . 5.3.2.4. Daily Measurement ControlThe operator should select a reasonable method to verify daily that the inertial profiling system utilized can produce consist
46、ent results under normal operating conditions on pavements typically encountered during data collection. Options include using a control section as described in Section 5.3.2.4.1 or checks using the previous days data as described in Section 5.3.2.4.2. The surface texture of the section used for dai
47、ly verification should be similar to that on which measurements are to be obtained for QC/QA purposes. 5.3.2.4.1. For profilers used for QC/QA of new construction, control sections can be established by selecting one or more 0.1-mile sections with a maximum IRI of 120 in./mile that will maintain a c
48、onsistent ride profile over the time period when daily checks are needed. For profilers used for network-level profiling, several control sections having a range of IRI up to 200 in./mile may be selected as control sections, and profiled at regular intervals. A profiler certified within the past 90
49、days should determine the IRI of the control section(s) by making a series of at least five profile measurements. The average IRI of the measurements shall be used to establish the IRI of the control section(s), provided that the cross-correlation of the measurements, as determined using the latest version of ProVAL, is at least 88 percent (value is dependent on the filters used, spectral content of the measured surface, operator, etc.). Once established, the control section(s) can be used to validate
