AASHTO R 56:14(2018) Standard Practice for Certification of Inertial Profiling Systems.
3.1.1. high-pass filtering—reduces the effect of long wavelengths that arc associated with gradual elevation changes such as hills.
3.1 .2. International Roughness Index aRIi—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
longitudinal profile are referenced in ASTM El926.
3.1.3. line laser—a line laser obtains a series of data points along a line, which is typically perpendicular to the travel direction, with the line typically being 4 in. long. A single, bridged elevation value is computed from this data.
3.1.4. longitudinal profile—the vertical deviations of the pavement surface taken along a line in the direction of travel referenced to a horizontal datum.
3.1.5. report interval—the longitudinal distance between the outputs of a profile index value.
3.1 .6. sample interval—the longitudinal distance between data capture points. The data include location, height, and accelerometer values. These data points are combined to create one profile data point. These points, in turn, may be combined to create a final value in the reported profile.
This practice outlines standard procedures for certifying and verifying the operational accuracy and repeatability of inertial profiling equipment. It also provides guidance for qualifying the equipment operators.
Minimum Requirenients The inertial profiling system must meet all requirements and specifications found in M 328.
5.2. The profiler software must be able to calculate and report the IRI (in in./mile or appropriate SI units) from the corresponding measured true profile and permit the operator to:
5.2.1. Automatically trigger the start of data collection at the designated location;
5.2.2. Provide the measured true profiles in electronic text files following the formats prescribed by R 57, in addition to any binary data file storage provided. These profile data are necessary to evaluate profiler accuracy and repeatability and to verify the height and distance measurements as described herein.AASHTO R 56 pdf download.