COMPARISON OF LOAD RESTRICTION TIMINGS DETERMINED USING FHWA GUIDELINES AND FROST TUBES

The Federal Highway Administration (FHWA) method and frost-tube measurements are employed in Wisconsin to determine the timing and duration of spring load restrictions. Depth of freeze or thaw is used in both methods to determine when to apply load restrictions and to estimate their duration. The FHWA method uses average daily air temperatures to predict the beginning and end of freeze and/or thaw. Frost tubes directly measure the depth of freeze and/or thaw. This paper describes an analysis in which the two methods are compared using air-temperature data and frost-tube data obtained in Wisconsin. The analysis reveals that variations exist between predicted and measured freeze and thaw conditions. The FHWA method is early in predicting the start of freeze and late in predicting the start of thaw. It is, however, late when used to estimate the end of thaw. A case study is presented to compare the two methods.

Language

  • English

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Filing Info

  • Accession Number: 00719291
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 19 1996 12:00AM