Design of Various Shear Connectors for Repair of Corroded Steel Girders with Ultra-High Performance Concrete

Abstract

Corrosion accounts for approximately 20% of the structurally deficient bridges in the United States, causing a massive backlog of rehabilitation projects. The current repair procedure for corroded bridge girders is expensive, slow to implement, and necessitates complete closure of the bridge. Through an extensive study supported by the Connecticut Department of Transportation, a novel repair method has been developed to rapidly restore the strength of corroded bridge girder ends with minimal traffic interruption. First, shear connectors in the form of headed studs are welded on the uncorroded web plate above the bearing. Next, formwork is placed and ultra-high-performance concrete (UHPC) is cast down to the bottom flange. This creates an alternate load path around the section loss. Based on the experimental results, it may be concluded that the implementation of the repair reduces the strains on the web plate and strengthens the bridge girder, allowing it to surpass its original capacity. However, the success of the repair centers around the performance of the shear connectors. In addition to headed studs, threaded bars and UHPC dowels in perforated web were evaluated experimentally as alternative shear-transfer mechanisms. This paper presents the repair design objectives and considerations for a realistic girder end utilizing different shear connectors to demonstrate the flexibility and versatility of the repair. The details of the designs are illustrated to facilitate the transition of the research findings to practice.