Metric conversion is discussed in terms of tunnel design and construction, tunnel equipment is considered, and experiences abroad are related. A basic problem that will be encountered is the loss of mental standards. This will tend to increase errors until such standards are reaquired. Conversion to the new system will lead to an increase of inventory levels. Owners of tunnel projects will have to make a more thorough check of the low bidders on a tunneling project-of their methods of calculation of quantities and methods of accomplishing a job. Tooling and rigs and fixtures will require conversion. Drawings and standards may also need to be converted. The availability of metric components could also pose problems. The effect of conversion in the area of tunnel support and problems associated with meeting certain stress levels are discussed. Segmental lining will have to be redesigned. In construction, the question of pay quantities and measurements, and new or recalibrated measuring equipment must be considered. Contractors may have difficulty in reprogramming computers to estimate costs. Problems associated with haulage systems (track gauge, etc.), ventilation (duct size), tunnel lining forms, tunneling and other excavating machines are noted. Fasteners and fittings are the main problems associated with tunneling equipment manufacture. Comments are made on bearings, gearing and spinning problems. Gradual change to metric in a hydraulic motor manufacture in Australia is outlined, and other experiences are quoted.

  • Supplemental Notes:
    • Report of a symposium conducted by Standing Subcommittee No 5, International Activities of the U.S. National Committee on Tunneling Technology, held on May 21-22, 1974 in Washington, D.C.
  • Corporate Authors:

    National Research Council

    National Committee on Tunneling Technology
    Washington, DC  United States  20418
  • Authors:
    • Robins, R J
  • Publication Date: 1975

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Filing Info

  • Accession Number: 00127935
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 21 1976 12:00AM