In 1993, a violent flood on the Gila River destroyed the Gillespie Dam. The surge of water also caused minor damage to the bridge by causing some of its support piers to settle. However, due to its strong steel truss design and the fact the concrete support piers were sunk into the bedrock, the bridge didn't collapse. The bridge's design is also the reason for its longevity. From 2011 to 2012, the Gillespie Dam Bridge underwent a $7,300,000 restoration by Maricopa County. The project included strengthening of the concrete piers and steel truss sections, as well as replacement of the roller bearings and construction of the Gillespie Dam Interpretive Plaza. The Gillespie Dam Bridge and Boulder Creek Bridge are the only surviving multiple span steel through truss bridges in Arizona. On September 21, 2018, the Gillespie Dam Bridge along with Old US 80 Highway were designated as part of Historic U.S. Route 80 by the Arizona Department of Transportation.