AASHO Road Test tandem axle loads were analyzed to determine the magnitude of the tandem axle load that causes the same damage as an 80-kN (18,000-lbf/sq in.) single axle load. The procedure is outlined and is the same as that used to analyze single axle loads. The essential findings were as follows: One repetition of a 151-kN (34,000-lbf/sq in.) tandem axle load appears to cause the same damage as one repetition of an 80-kN single axle load. The relationship of the log of the number of repetitions of load versus the axle load, which is used in Kentucky, appears to be equally valid for single and tandem axle loads. The use of superposition principles and equivalency of repetitions, in combination with terminal serviceability indexes, permits analyses of the tandem-axle-load data and comparsion with equivalent Kentucky thickness designs converted to the AASHO structural number. Single-axle-load analyses were combined with the tandem-axle-load analyses and superimposed by Kentucky equivalent designs. The Kentucky designs, based on elastic theory, envelop 91 percent of the AASHO Road Test data. For pavement design, the estimated fatigue for a 20-year design that uses the AASHO damage factors will be reached in 16.2 years if the Kentucky damage factors are used. The Kentucky damage factors more closely approximate observed behavior than do the AASHO factors. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 57-63
  • Monograph Title: Analysis of pavement systems
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00193382
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: May 11 1979 12:00AM