The result of this study demonstrated that uncoated weathering steel bridges designed and detailed in accordance with the recommendations outlined in the FHWA Technical Advisory will perform well. The study focused on 63 bridges in 11 states and the commonwealth of Puerto Rico that have been in service between 18 and 30 years. The positive performance of these bridges indicates that the original selection of uncoated weathering steel was a cost-effective decision. At a minimum, the decision eliminated the need for initial painting and eliminated at least one additional maintenance painting over the years of operation. Bridge deck drainage, a common problem, is found to affect structural bridge elements, specifically when salt-laden roadway drainage comes into frequent contact with the uncoated steel.
Uncontrolled drainage is also detrimental to the substructure.
The effects of uncontrolled bridge deck drainage are usually confined to localized areas in the vicinity of the joint. These effects are mitigated in jointless bridges and bridges with integral abutments. The Phase- III Report focuses on specific conditions and environments that could affect material performance. These include grade separations, water crossings, marine and industrial environments, weather-related moisture, bridge joints, deck drains, staining of substructure and fatigue.