In December 2011, as the Historic Gillespie Dam Bridge approached its 85th year of service, the Maricopa County Department of Transportation began a major rehabilitation and repair effort to preserve one of Arizona's earliest and most significant commerce and transportation structures. The work included heat straightening bent steel members damaged over the years by automobiles and large farm vehicles, repairing pipe rail and sway bracing, installing new approach guard railing, making concrete repairs and wing wall modifications, and reinforcing bridge piers in accordance with United States Department of the Interior and Arizona State Historic Preservation Office guidelines. The roadway approaches at each end of the bridge were repaved, and an interpretive plaza was built to enhance public access and enjoyment. A significant part of the project involved hydraulically jacking the bridge span by span to remove the original rusted, nonfunctioning roller bearings and install new pad bearings that allow the steel spans to expand and contract during temperature changes. The rehabilitation ensured that the Gillespie Dam Bridge would be conserved for future generations and enjoyed into Arizona's second century.