Performance of Uncoated Weathering Steel Bridge Inventories: Methodology and Gulf Coast Region Evaluation

Abstract

Although the majority of uncoated weathering steel (UWS) structures are performing well when designed and maintained in accordance with existing recommendations, exceptions to this trend exist. Additionally, the guidance on UWS use is largely qualitative. For these reasons, a data-driven method for assessing deterioration of a large sample of bridges as a function of environment was formulated, piloted, assessed, and validated. Key aspects of the methodology include the development of a database that uses graphical information systems to quantify the climate of hundreds of structures, a statistically driven process for selecting a representative sample of bridges for further evaluation, and a review of bridge performance based on owners’ evaluations and independent field evaluations. As a result of applying this methodology to UWS bridges with proximity to the Gulf Coast, environments consistently resulting in satisfactory performance were quantified; a rare combination of severe proximity to the coast, humidity, and atmospheric concentrations of chloride was also quantified and correlated with the small number of bridges with overall inferior corrosion performance in these marine environments.