INVESTIGATION OF CONSTRUCTION TECHNIQUES FOR TACTICAL BRIDGE APPROACH ROADS ACROSS SOFT GROUND

The objective of this study was to investigate and test the feasibility of various new techniques for constructing bridge approach roads across soft ground. A test section containing seven test items was constructed on a soft clay subgrade which has an average strength of 0.9 CBR. Accelerated traffic tests were conducted using various loads on a 5-ton military dump truck. Traffic was recorded in terms of coverages of equivalent 18-kip single-axle, dual-wheel load operations. A major finding of this investigation was the potential use of sand-confinement systems for base courses over soft subgrades. Both a large-volume confinement system and a small-volume system outperformed the crushed stone control item by a substantial margin. This investigation also showed that the placement of a fabric or membrane between a soft clay subgrade and crushed stone base can offer substantial savings in the design thickness of a road. Polyester fabric was identical with the control item except that pervious polyester fabric was placed between the base and subgrade. This item withstood 2500 coverages before developing an 11-in. rut. This represented a savings in design thickness of approximately 27 percent. T-16 membrance was also identical with the control item except that an impervious coated nylon membrane (T-16) was placed between the base and subgrade. This item sustained 37,000 coverages before developing an 11-in. rut. This represented a design thickness savings of 48 percent. /Author/

  • Corporate Authors:

    U.S. Army Waterways Experiment Station

    3909 Halls Ferry Road
    Vicksburg, MS  United States  39180-6199
  • Authors:
    • Webster, S L
    • Watkins, J E
  • Publication Date: 1977-2

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 75 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00155964
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Technical Rpt S-77-1Final Rpt.
  • Files: TRIS
  • Created Date: Sep 28 1977 12:00AM