The Benkelman beam was used for the pavement design of a highway in Thailand over soft, deltaic clay soils. Because little technical information on the validity of this technique over soft clays becomes available, research into testing techniques was carried out. It was found that a seasonal deflection effect occurred, that the temperature correction factor is less in tropical countries than in temperate climates, that the movement of the front leg of the Benkelman beam was significant over soft clay subgrades, and that the Canadian test procedure was preferable to the Western Association of State Highway Officials test procdure. It was concluded that design deflection criteria established by Canadian and British pavement trials were applicable to highways over soft clay subgrades, and design deflections for both the Canadian and British Benkelman beam testing procedures were determined. Benkelman beam tests were carried out during construction to check that these values were obtained, and they indicated that practically all readings fell below the design limits. The constructed pavement was therefore considered to be adequate. Tests on various pavement layers indicated that the crushed rock base course was the most effective material in reducing deflections relative to its cost over these soft clays, and this resulted in a pavement redesign that resulted in construction cost savings of $700,000. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 85-96
  • Monograph Title: Pavement design, performance and rehabilitation
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00139564
  • Record Type: Publication
  • ISBN: 0309024854
  • Files: TRIS, TRB
  • Created Date: Sep 16 1976 12:00AM