This paper proposes an alternative procedure for computing pavement thickness requirements for heavy duty pavements (project roads). Flexible pavement design analysis is mainly based on three factors: (1) subgrade strength; (2) vehicular traffic; (3) pavement serviceability. In India, the CBR (California Bearing Ratio) measure of subgrade strength has been favoured by pavement designers for various reasons. Its advantages and disadvantages are discussed in some detail, and several other methods are compared with it. Allowable subgrade pressure in Gray's formula has been defined as the subgrade's bearing value. The authors suggest the following computation method for obtaining pavement thickness using Gray's formula: (1) carefully study the traffic mix likely to occur at a project site; (2) calculate the total load and radius of the contact area on the basis of the proportions of vehicle types; (3) add an extra impact factor of 20% of the rated rear axle load of each vehicle type; and (4) apply the known graphical relationship between CBR and soil bearing value. Several numerical examples are worked out in detail. The authors conclude that the method agrees well with earlier methods, and should be considered for the practical evaluation of pavement thickness requirements.

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  • Corporate Authors:

    Indian Roads Congress

    Jamnagar House, Shahjahan Road
    New Delhi,   India  110 011
  • Authors:
    • GOSWAMI, N K
    • BHASIN, N K
  • Publication Date: 1993-9


  • English

Media Info

  • Features: References;
  • Pagination: p. 17-27
  • Serial:
    • Indian Highways
    • Volume: 21
    • Issue Number: 9
    • Publisher: Indian Roads Congress
    • ISSN: 0376-7256

Subject/Index Terms

Filing Info

  • Accession Number: 00662462
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jul 28 1994 12:00AM