LIVE-LOAD GIRDER DISTRIBUTION FACTORS FOR BRIDGES SUBJECTED TO WIDE TRUCKS

An important problem facing engineers and officials in the United States is the constraint imposed on transportation due to limitations of bridges. These limitations typically constrain vehicles to minimum heights and widths, to minimum and maximum lengths, and to a maximum allowable weight. However, with current demands of society and industry, there are times when a truck must carry a load that exceeds the size and weight of the legal limit. In this situation, the trucking company requests from the state departments of transportation an overload permit. For a truck with a wheel gauge larger than 1.8 m (6 ft), the process of issuing a permit for an overload truck requires a tremendous amount of engineering efforts. This is because the wheel load girder distribution factors (GDFs) in the design specifications cannot be used to estimate the live-load effect in the girders. In some cases, an expensive and time-consuming finite element analysis may be needed to check the safety of the structure. In this study, the finite element method is used to develop a modification factor for the GDF in AASHTO's "LRFD Bridge Design Specifications" to account for oversized trucks with a wheel gauge larger than 1.8 m. To develop this factor, nine bridges were considered with various numbers of girders, span lengths, girder spacings, and deck slab thicknesses. The results indicated that use of the proposed modification factor with the GDF in the design specifications can help increase the allowable load on slab-on-girder bridges.

• Record URL:
  https://doi.org/10.3141/1696-56
• Summary URL:
  http://scholar.google.com/scholar_lookup?title=LIVE-LOAD+GIRDER+DISTRIBUTION+FACTORS+FOR+BRIDGES+SUBJECTED+TO+WIDE+TRUCKS&author=S.+Tabsh&author=M.+Tabatabai&publication_year=2000
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309071224
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1696, Fifth International Bridge Engineering Conference, April 3-5, 2000, Tampa, Florida, Volume 2. The revised name of this series is Transportation Research Record: Journal of the Transportation Research Board.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Tabsh, S W
  • Tabatabai, M
• Conference:
  • Fifth International Bridge Engineering Conference
  • Location: Tampa, Florida
  • Date: 2000-4-3 to 2000-4-5
• Publication Date: 2000

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 144-149
• Serial:
  • Transportation Research Record
  • Issue Number: 1696
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Bridges; Design; Finite element method; Girders; Live loads; Load and resistance factor design; Load limits; Oversize loads; Overweight loads; Permits; Safety; Specifications; Wheel loads
• Uncontrolled Terms: Girder distribution factors; Modification factor
• Subject Areas: Bridges and other structures; Design; Highways; Safety and Human Factors; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00789731
• Record Type: Publication
• ISBN: 0309071224
• Files: TRIS, TRB, ATRI
• Created Date: Mar 8 2000 12:00AM