Bridges, Tunnels and other Transportation Structures
Steel girder bridges are prone to corrosion, particularly near girder web-bottom flange interfaces and at girder ends, in climates that require deicing agents. Section losses can change failure modes over time, and may leave sections vulnerable to undesirable failure modes such as buckling. This paper investigated the remaining capacity of W-shaped steel bridge girders that have web section loss due to corrosion. Using finite element modeling, buckling and moment capacities were obtained for girders with different localized section loss amounts, and locations in the web. The capacities obtained from finite element analyses were compared with predictions of AASHTO LRFD Bridge Design Specifications, making varying assumptions on web thickness. Accuracy and conservatism levels of these assumptions were evaluated, using an actual bridge with measured corrosion damage as a case study. The results were used to develop guides that relate girder web thinning to loss in moment, shear and buckling capacity for load rating purposes.