USE OF TRAFFIC DATA FOR CALCULATING EQUIPMENT 18000 LB SINGLE AXLE LOADS

IN A PREVIOUS REPORT ONE OF THE AUTHORS PROPOSED A REVISED METHOD, BASED ON THE PERFORMANCE OF 49 IN-SERVICE TEST SECTIONS, FOR DESIGNING FLEXIBLE PAVEMENTS IN MINNESOTA. ONE OF THE IMPORTANT PARAMETERS REQUIRED IN ORDER TO USE THIS PROCEDURE IS THE TRAFFIC FACTOR IN TERMS OF THE TOTAL NUMBER OF EQUIVALENT 18,000-LB SINGLE AXLE LOADS TO GO OVER A PROPOSED PAVEMENT SECTION DURING A GIVEN DESIGN PERIOD. THIS FACTOR AND THE EMBANKMENT STRENGTH IN TERMS OF A STABILOMETER R-VALUE ARE USED TO ESTABLISH A PAVEMENT SECTION THICKNESS FACTOR CALLED THE GRAVEL EQUIVALENT. THE EQUIVALENT LOAD CONCEPT MAKES IT POSSIBLE TO CALCULATE THE DESTRUCTIVE EFFECT OF VARIOUS AXLE LOADS RELATIVE TO A BASE OR STANDARD AXLE LOAD (18,000-LB). THE RELATIONSHIP BETWEEN THE BASE AXLE LOAD AND THE RESPECTIVE AXLE LOADS ARECALLED "EQUIVALENCY FACTORS". FROM A SAMPLE OF WEIGHTS FOR THE VARIOUS TYPES OF TRUCKS AND MULTIPLYING THESE WEIGHTS BY THE APPROPRIATE EQUIVALENCY FACTORS, IT IS POSSIBLE TO CALCULATE THE AVERAGE EFFECT OF EACH VEHICLE TYPE. THIS TERM, CALLED AN "N-18 FACTOR," CAN VARY WITH LOCATION AND TIME. THE TOTAL NUMBER OF EQUIVALENT LOADS FOR A GIVEN YEAR IS CALCULATED BY MULTIPLYING THE N-18 FACTORS FOR EACH VEHICLE TYPE BY THE NUMBER OF VEHICLES IN THAT CATEGORY AND SUMMING THESE VALUES FOR ALL VEHICLE TYPES. THE SAME PROCEDURE IS FOLLOWED FOR EACH YEAR OF THE DESIGN PERIOD AND SUMMED TO GIVE THE TOTAL SUMMATION OF EQUIVALENT LOADS. IN THIS REPORT A METHOD IS PROPOSED FOR DETERMINING THE SUMMATION OF EQUIVALENT 18,000-LB SINGLE AXLE LOADS. THE METHOD INCLUDES WAYS OF ESTIMATING THE N-18 FACTORS FOR EACH RYPE OF VEHICLE IN A GIVEN LOCATION USING DATA OBTAINED FROM A 1964 TRAFFIC STUDY MADE ON MINNESOTA TEST SECTIONS. APROPRIATE ANNUAL INCREASES IN THE N-18 FACTORS BASED ON STATEWIDE DATA OVER THE LAST 15 YEARS ARE ALSO PRESENTED. A COMPUTER PROGRAM IS PRESENTED WHICH WILL ANALYZE THIS INFORMATION AND CALCULATE THE NUMBER OF EQUIVALENT 18,000-LB SINGLE AXLE LOADS FOR EACH YEAR OF THE DESIGN PERIOD. /AUTHOR/

  • Supplemental Notes:
    • No 183, 62 PP, 8 FIG, 16 TAB, 8 REF
  • Corporate Authors:

    Minnesota Department of Highways

    ,    
  • Authors:
    • Skok, E L
    • Root, R E
  • Publication Date: 1970

Subject/Index Terms

Filing Info

  • Accession Number: 00202013
  • Record Type: Publication
  • Files: TRIS, STATEDOT
  • Created Date: Dec 20 1971 12:00AM