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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Experimental Validation of New Improved Load Rating Procedures for Deteriorated Unstiffened Steel Beam Ends

As New England's bridge population ages, inspection engineers at State Transportation Departments are increasingly witnessing instances of extensive corrosion at unstiffened steel beam ends. The increased incidence of this condition can be primarily attributed to leaking through deck joints. The resulting section loss can lead to a significant reduction in the girder's safe calculated load carrying capacity. Several cases exist where the extreme effects of this phenomenon have incurred closure of the bridge to ensure life safety. The non-uniformity of the corroded shape, as well as the variable thickness reduction along the corroded area provide substantial challenges in calculating realistic estimates of the remaining capacity of the girder's end. The goal of this work is to enhance load rating methods for assessing corroded unstiffened beam ends to avoid overly conservative bridge posting recommendations. The new developed methods from ongoing research in the state of Massachusetts calculate more accurately the load carrying capacity. However, the wide application of the new procedures needs to be validated with experiments including several different configurations, beam sizes, corrosion shapes, and support conditions. Laboratory testing will validate and enrich the new procedures while providing valuable insight into the failure mechanisms that control these scenarios. Finally, finite element computational calculations will be calibrated using the produced experimental data from full-scale testing of the corroded beams.