Comparison of Bridge Rating Methods

Abstract

The working stress, load factor and autostress methods are applied to the rating of composite and noncomposite steel beam and girder bridge structures. These three methods are developed and used to rate a series of 16 representative bridges with a wide range of span lengths. The rating factors resulting from these analyses are compared to each other and correlated with the span length by means of a linear regression. The results of the regression allow the engineer to predict the increase in the rating factor obtained by utilizing load factor and autostress methods over that given by the universally recognized working stress method.