The American Association of State Highway and Transportation Officials (AASHTO) Guide Specification for Service Life Design of Highway Bridges (HBSLD-1) and Guide to Bridge Preservation Actions (BPA-1) have had a positive impact on state departments' of transportation (DOTs) ability to design concrete structures to achieve a target service life. Within HBSLD-1, resistance to chloride-induced corrosion deterioration in concrete has been calibrated based on full probabilistic service life modeling. However, current design methods for structural steel take the form of deemed-to-satisfy provisions based on past practices and historical performance without probabilistic calibration. A more rigorous probabilistic method using a deterioration model for steel structures is desired to achieve improved reliability to meet the selected target service life. The model would allow steel elements to be designed for service life demands (e.g., environmental exposure conditions) in addition to other AASHTO LRFD Bridge Design Specifications limit states. Research is needed to develop and validate deterioration models for steel bridge elements.
