A METHOD OF DESIGN OF NON-RIGID PAVEMENTS FOR HIGHWAYS AND AIRPORT RUNWAYS

THIS PAPER PRESENTS A METHOD FOR ARRIVING AT THE PROPER THICKNESS OF THE NONRIGID TYPE OF PAVEMENT SURFACE TO SUPPORT A GIVEN WHEEL LOAD CARRIED ON A GIVEN TYPE OF TIRE EQUIPMENT. BY MEANS OF TESTS MADE IN THE LABORATORY BY THE USE OF A BIN 6FT. SQ., THE MANNER OF DISTRIBUTION OF SUBGRADE PRESSURES HAS BEEN DETERMINED UNDER DIFFERENT THICKNESSES OF FROM 4 TO 10 IN. OF PAVEMENT SURFACE. LOADS WERE APPLIED BY MEANS OF A HYDRAULIC JACK TO ELLIPTICAL SHAPED BEARING BLACKS SIMULATING TIRE IMPRINT AREAS. IT IS ASSUMED THAT A NON-RIGID PAVEMENT SHOULD BE OF SUCH THICKNESS THAT THE MAXIMUM PRESSURE OBTAINED UNDER THE CENTER OF THE WHEEL SHOULD AT NO TIME EXCEED THE BEARING VALUE OF THE SUBGRADE. A METHOD IS SUGGESTED FOR DETERMINING BEARING VALUE, MAKING USE OF A BEARING BLOCK OF 100 SQ. IN. IN AREA. FORMULAS ARE DERIVED FOR THICKNESS, FIRST MAKING THE ARBITRARY ASSUMPTION THAT THE SUBGRADE PRESSURES ARE CONFINED WITHIN AN AREA ON THE SUBGRADE INCLUDED WITHIN THE LINES SLOPING 45 DEG. FROM THE TIRE IMPRINT AREA. THE UNIFORM PRESSURE IS THEN EXPRESSED IN TERMS OF THE ACTUAL MEASURED PRESSURE, WHICH IN TURN IS ASSUMED TO BE EQUAL TO THE SUBGRADE SUPPORTING VALUE. THUS, FORMULAS ARE DERIVED FOR THICKNESS IN TERMS OF WHEEL LOAD, SUBGRADE SUPPORTING VALUE AND THE DIMENSIONS OF THE IMPRINT AREA OF THE TIRE. THESE DIMENSIONS ARE KNOWN FOR GIVEN LOADS, TIRE EQUIPMENT AND INFLATION PRESSURES. AS THE RESULT OF THE FORMULAS THUS DERIVED, THICKNESS MAY BE DETERMINED AFTER A PRESSURE TEST IS MADE TO DETERMINE THE SUPPORTING POWER OF THE SUBGRADE. FOR GENERAL PURPOSES OF DESIGN, THE PRESSURE TESTS INDICATE THAT THE MAXIMUM MEASURED PRESSURE UNDER STABLE, NON-RIGID SURFACES MAY BE TAKEN AT 2 TO 2 1/2 TIMES THE UNIFORM PRESSURE CALCULATED AS ABOVE INDICATED. ON THIS BASIS, CURVES FOR THE REQUIRED THICKNESS ARE SHOWN IN TERMS OF WHEEL-LOAD AND SUBGRADE SUPPORT. /AUTHOR/

  • Supplemental Notes:
    • Vol 20, pp 258-270, 8 FIG, 3 TAB
  • Authors:
    • Goldbeck, A T
  • Publication Date: 1941

Media Info

  • Monograph Title: Proceedings of the Twentieth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 3-6, 1940
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00205887
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM