In 1931 the American Association of State Highway and Transportation Officials (AASHTO) published "Standard Specifications for Highway Bridges and Incidental Structures", the first bridge design standard ever undertaken in the United States. The specifications quickly became a national U.S. standard and were copied and used by many other countries as their national standard. The sections on "Incidental Structures" were dropped in the second edition, published in 1935. By 1986, more than 50 years and 12 editions later, the specifications were still in effect in the United States. During that time, however, bridge engineering theory and technology changed significantly. Materials and construction methods improved. Computers became standard design and evaluation tools and provided engineers with a better understanding of how bridges carried and responded to loads. Finally, the need to carry more frequent and heavier loads put a strain on the entire process of bridge design, construction, and inspection. An NCHRP project was initiated in 1986 to assess the U.S. bridge design specifications, review foreign codes and alternative specification philosophies, and present options for improving the specifications and overall bridge design process. This project was completed a year later, recommending an NCHRP study to develop a limit-states code. NCHRP Project 12-33 was initiated in mid-1988. The remainder of this article discusses this project, which is currently preparing the final draft of the new bridge specifications. It is anticipated that the final draft will be completed and submitted in early April 1992 and that AASHTO will consider it for adoption in 1993.

Media Info

  • Features: Figures; Photos;
  • Pagination: 3 p.
  • Serial:
    • TR News
    • Issue Number: 158
    • Publisher: Transportation Research Board
    • ISSN: 0738-6826
  • Publication flags:

    Open Access (libre)

Subject/Index Terms

Filing Info

  • Accession Number: 00622290
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: May 31 1992 12:00AM