Probabilistic Lifecycle-Cost Assessment of Weathering-Steel Girder-End Protection Strategies

Localized corrosion at weathering-steel girder ends near the bearings and deck joints can necessitate recurring maintenance and premature replacement. However, span-dependent comparisons of localized protection strategies under treatment-quantity, service-life, and economic uncertainties remain limited. This study develops a probabilistic lifecycle-cost framework comparing Paint + Replace, Paint + Repaint, Metalize + Remetalize, and preventive ultra-high-performance concrete (UHPC) encapsulation. A paired Monte Carlo analysis evaluated one million simple-span girders spanning 20–200 ft (6.1–61.0 m), with costs assessed at construction and after 75 and 150 years. Uncertainties in span, unit costs, paint service life, removal costs, and discount rates were incorporated. Outputs included mean lifecycle costs, distributions, lowest-cost probabilities, sensitivity analyses, and UHPC break-even thresholds. Assuming no future maintenance of the UHPC encasement or remaining paint, UHPC had the lowest mean cost in every span group at 75 and 150 years. At 150 years, its overall mean was $67.27k/girder, compared with $67.95k/girder for metalizing. Repainting the remaining painted region increased the UHPC mean to $68.54k/girder, placing it third. The findings demonstrate the importance of maintenance assumptions and of distinguishing mean cost from lowest-cost probability. The framework provides a basis for project-specific evaluation and comparison of girder-end protection strategies using locally calibrated inputs.