Test results on relation of impact to speed are reported to support the proposed Article 107 of the Rules for Rating Existing Iron and Steel Bridges. It is noted that a study of short span steel bridges 20 to 40 ft. long and deck plate girder spans 40 to 130 ft. long subjected to live loads with or without hammer blow indicates that the reduction of impact as a result of speed should occur at 40 mph or less, rather than synchronous speed or less as was proposed in 1947 for spans longer than 50 ft. The value of 40 mph was selected as the maximum practical speed where allowable reduction in impact might be permitted since rolling equipment without hammer blow has no synchronous speed. It is noted that some values of total impact on truss spans approximately 120-150 ft. long, subjected to equipment with hammer blow, receive more impact than is provided by Article 206 of the Specifications for Steel Railway Bridges. The character of the reduction equation for truss spans subjected to rolling equipment with hammer blow is consistent with the data.

  • Corporate Authors:

    American Railway Engineering Association

    59 East Van Buren Street
    Chicago, IL  United States  60605
  • Publication Date: 1949

Media Info

  • Features: Figures; Tables;
  • Pagination: p. 432-443
  • Serial:
    • Volume: 50
    • Publisher: American Railway Engineering Association

Subject/Index Terms

Filing Info

  • Accession Number: 00052457
  • Record Type: Publication
  • Source Agency: Association of American Railroads
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Jul 15 1976 12:00AM