Fatigue life assessment of a steel bridge based on measured corrosion wastage and actual traffic loading

Abstract

Most steel bridge failures and collapses demonstrate that environmental influences substantially impact the structural integrity of steel bridges. Fatigue and corrosion have been recognized as the primary aging processes for steel bridges, especially in marine environments. Acknowledged gaps in research due to the absence of detailed guidelines for evaluating structural integrity in relation to fatigue and corrosion are problematic. Additionally, the absence of general S-N curves for structures of steel prone to corrosive environments, alongside the lack of research on both fatigue and corrosion increasing the vulnerability and failure of steel classes used in bridges, makes the estimation of the fatigue life of steel bridges uncertain. Estimating the remaining service life accurately is crucial to using the available infrastructure efficiently. This thesis determines a more accurate fatigue life for steel road bridges based on measured corrosion wastage and actual traffic loads. Corrosion fatigue, one of the main factors in reducing the fatigue life of a steel bridge, is explored at the same time. A conventional approach (Miner’s rule) and two current proposed methods are used alongside different scenarios of actual traffic loads to calculate the fatigue life of a specific steel bridge (Storåna I bridge in Norway). A database gathered from the bridge’s visual and technical inspections is used while estimating the fatigue life of the bridge. Moreover, a comparison and discussion of results assembled from the conventional method and the two current proposed methods used alongside different scenarios of actual traffic loads are illustrated within the thesis.