USE OF TRAFFIC DATA FOR CALCULATING EQUIVALENT 18,000-LB SINGLE-AXLE LOADS
A METHOD FOR FLEXIBLE PAVEMENT THICKNESS DESIGN HAS BEEN PROPOSED FOR USE IN MINNESOTA. IT REQUIRES THE CALCULATION OF SUMMATION OF EQUIVALENT 18,000-LB AXLE LOADS DURING A DESIGN PERIOD. TO CALCULATE EQUIVALENT LOADS REQUIRES A KNOWLEDGE OF EQUIVALENCY FACTORS FOR VARIOUS AXLE LOADS AND CONFIGURATIONS, TOTAL TRAFFIC, VEHICLE-TYPE DISTRIBUTION, AND AXLE-LOAD DISTRIBUTION WITHIN EACH VEHICLE TYPE. THE LOAD DISTRIBUTION FOR EACH TYPE OF VEHICLE IS LAID OUT N THE FORMAT OF A STANDARD W-4 TABLE, AND THE AVERAGE EFFECT IS DETERMINED AND CALLED AN N-18 FACTOR FOR EACH TYPE OF VEHICLE. AXLE-LOAD EQUIVALENCIES, TAKEN FROM THE AASHO ROAD TEST, ARE DEPENDENT ON THICKNESS INDEX AND TERMINAL SERVICEABILITY INDEX. BASED ON A TRAFFIC-LOAD AND VEHICLE-TYPE DISTRIBUTION STUDY ON 40 MINNESOTA TEST SECTIONS, IT WAS FOUND THAT DESIGN THICKNESSES CAN VARY BY 2 TO 3 IN. OF GRANULAR EQUIVALENT FOR VARIATIONS IN VEHICLE-TYPE DISTRIBUTION AND UP TO 10 IN. FOR TYPICAL VARIATIONS IN VEHICLE-WEIGHT DISTRIBUTION. A COMPUTER PROGRAM, WHICH CAN BE USED ON EITHER THE IBM 360 OR THE CDC 6600, HAS BEEN DEVELOPED TO CALCULATE EQUIVALENT 18,000-LB AXLE LOADS BY USING TOTAL VOLUME, VEHICLE-TYPE DISTRIBUTION, AND AXLE-LOAD DISTRIBUTION DATA. GENERALLY, VOLUME AND VEHICLE-TYPE DISTRIBUTION DATA ARE AVAILABLE FROM HIGHWAY DEPARTMENT TRAFFIC SECTIONS. HOWEVER, LOAD DISTRIBUTION DATA ARE NOT USUALLY AVAILABLE EXCEPT ON A STATEWIDE BASIS. HISTOGRAMS ARE PESENTED SHOWING VARIATIONS IN THE AVERAGE EFFECT OF VARIOUS TYPES OF VEHICLES IN TERMS OF AVERAGE NUMBER OF EQUIVALENT 18,000-1B AXLE LOADS PER PASSAGE OF THAT TYPE OF VEHICLE. THE COMPUTER PROGRAM IS NOW USABLE FOR FLEXIBLE PAVEMENT DESIGN.
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Supplemental Notes:
- Sponsored by Committee on Flexible Pavement Design. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Skok Jr, Eugene L
- Root, Richard E
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Conference:
- 51st Annual Meeting of the Highway Research Board
- Location: Washington District of Columbia, United States
- Date: 1972-1-17 to 1972-1-21
- Publication Date: 1972
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: pp 65-75
- Monograph Title: Pavement technology
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Serial:
- Highway Research Record
- Issue Number: 407
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Axle load force; Computer programs; Flexible pavements; Load transfer; Pavement design; Pavements; Thickness; Traffic; Traffic equivalence factor; Vehicle characteristics
- Uncontrolled Terms: Pavement thickness
- Subject Areas: Highways; Operations and Traffic Management; Pavements;
Filing Info
- Accession Number: 00206042
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: May 15 1973 12:00AM