Postprint version. Published in Journal of Structural Engineering, Volume 131, Issue 5, May 1, 2005, pages 843-847.
NOTE: At the time of publication, the author Allen Estes was affiliated with the United States Military Academy - West Point, NY. Currently, August 2008, he is Head and Professor of Architectural Engineering at California Polytechnic State University - San Luis Obispo.
The definitive version is available at http://dx.doi.org/10.1061/(ASCE)0733-9445(2005)131:5(843).
The most common approach to assess the safety of a bridge is load rating. However, this approach cannot quantify the bridge safety in probabilistic terms or fully quantify the structural risk to the bridge. Reliability methods have become an increasingly popular and gradually accepted approach to assess the safety of structures. These methods account for the randomness and correlation of all relevant variables and failure modes in the analysis. This study performs both a load rating analysis and a reliability analysis on the same highway bridge, compares the results, and discusses the strengths and limitations of each approach.