Developing a probability based limit states bridge specification – U.S. experience

ABSTRACT: Europe, Canada and the United States have been developing new probabilistic limit states bridge design specifications, the Eurocode, the Canadian Highway Bridge Design Code (and the earlier Ontario Highway Bridge Design Code) and the AASHTO LRFD Specifications for Bridges (AASHTO LRFD). This paper summarizes the seven-year long process that led to the decision to develop the AASHTO LRFD, the objectives, and review process culminating in adoption in 1993. The implementation, further development during the decade since, and evolving plan to continue development of the specifications are discussed.