TxDOT had identified severe corrosion in critical zones at the ends of the steel girders. The complex connections trapped water and debris that resulted in continuous and severe corrosion over time. By the time this was identified, the situation had become critical and immediate action was required. Although emergency repairs were installed, they were only temporary measures to prevent further deterioration. A new bridge was being considered, but construction would not occur for at least 15-20 years, thus a long-term, permanent solution was needed to ensure 15 to 20 additional years of dependable service life from the existing bridge.
Conventional repair methods would have been difficult and costly to implement due to an unacceptable length of traffic closures on the bridge. The UHPC beam end repair technique, which involves removing corroded steel, installing headed shear connectors, and casting UHPC, provided an alternative solution that allowed the bridge to be repaired safely and with a minimum disruption to service. TxDOT selected UHPC for the project due to its high flowability, high strength, high ductility, and low permeability.
A recent Connecticut Department of Transportation project that had used UHPC to repair corroded girder ends and the supporting project research conducted by the University of Connecticut enhanced confidence in using the material.
After completion, the TxDOT team concluded that UHPC proved to be a highly effective tool to address multiple concerns in the corrosion repairs. TxDOT also believes UHPC shows great potential for further application in the rehabilitation of aging infrastructure across the nation.
