关键词: |
loads(forces), strength, design, winter, freezing, estimation, evaluation, structural analysis, south dakota |
摘要: |
During 1998-2002, the U.S. Geological Survey (USGS), in cooperation with SDDOT, conducted a study to evaluate factors affecting ice forces at selected bridges in South Dakota. The focus of this ice-force evaluation was on maximum ice thickness and ice-crushing strength, which are the most important variables in the American Association of State Highway and Transportation Officials (AASHTO) bridge-design equations for ice forces. Ice thickness was measured at six sites in South Dakota during 1999-2001 and ranged from 0 to 2.3 feet. Historical ice-thickness data measured by the USGS at eight selected streamflow-gaging stations in South Dakota also were compiled for 1970-97. Three ice-thickness-estimation equations that potentially could be used for bridge design in South Dakota were selected and included the Accumulative Freezing Degree Day (AFDD), Incremental Accumulative Freezing Degree Day (IAFDD), and Simplified Energy Budget (SEB) equations. An analysis of the data indicated that the AFDD equation best estimated ice thickness in South Dakota using available data sources with an average variation about the measured value of about 0.4 foot. Maximum potential ice thickness was estimated using the AFDD equation at 19 National Weather Service stations located throughout South Dakota. The estimated maximum potential ice thicknesses generally are largest in northeastern South Dakota at about 3 feet and are smallest in the southwest and south-central South Dakota at about 2 feet. / NOTE: Final rept. 1998-02. / Supplementary Notes: Sponsored by South Dakota Dept. of Transportation, Pierre. Office of Research. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA. |