摘要: |
Full-scale test data for multiple-wheel, heavy gear load (MWHGL) loading of flexible airport pavements are summarized from three separate test series: one test series, the MWHGL tests, was conducted by the U.S. Army Corps of Engineers (USACE), and the other two series of tests were conducted by the Federal Aviation Administration (FAA) at the National Airport Pavement Test Facility (NAPTF). The MWHGL pavement structural configuration was used as the reference, and all NAPTF structures were converted to equivalent reference structures by the use of thickness equivalency factors relating the NAPTF and the MWHGL structural materials. Load repetition factors (alpha factors), required for the computation of pavement thickness by the California Bearing Ratio (CBR) design procedure for flexible airport pavements, were calculated for the NAPTF test data and plotted with the MWHGL alpha factors. Least squares quadratic curve fits were computed for the four- and six-wheel alpha factors, and the alpha factors at 10,000 coverages were computed for comparison with the International Civil Aviation Organization (ICAO) standard for computing Aircraft Classification Number (ACN). The results of the analysis are consistent with the existing alpha factor of 0.825 for four-wheel gears, but the results of the analysis are not consistent with the existing alpha factor of 0.788 for six-wheel gears. The six-wheel alpha factor at 10,000 coverages should be changed to a value approximately equal to the interim value of 0.72 adopted by the ICAO for calculating ACN for six-wheel gears. |