File:Bridge across Rogue River in Gold Beach, OR.jpg

Many of the beautiful old bridges on the Oregon Coast were designed by Conde McCullough.

Bridges are now being preserved by an interesting process. The original structure of concrete and re-bar has deteriorated with the re-bar rusting and the concrete cracking. Where the damage has occurred, workers are replacing the rusted re-bar and then patching the concrete. Then a zinc coating is applied to the outside of the structure. A small electric current is passed through the zinc and the re-bar which protects the re bar. Works kind of like an anode / cathode system to electronically direct the corrosion to the zinc. The zinc can easily be replaced on the surface of the bridge. The current also tells if the re-bar becomes disconnected from itself so as to break the circuit. Oregon State Highway Department can monitor each bridge from the inside out this way.