‘Exploded’ paint prompts one-lane travel instances at Westport Island-Wiscasset bridge
In February, Maine Department of Transportation (MDOT) reduced travel on the Westport Island-Wiscasset bridge to one lane for a number of days. They have informed the Westport Island Select Board that travel over the bridge will be reduced to one-lane traffic for at least 12 weeks this year, so they can paint the bridge, sometime between May 1 and Nov. 30. But even before then, MDOT will be back to complete the work it started in February, the environmental cleanup of a catastrophic failure of the paint on the bridge.
The extreme sub-zero cold we experienced Feb. 3-4, followed by a rapid warming, caused the paint to explode in pieces off the bridge. Nancy Malone, who lives nearby on Bridge Street, saw the paint chips littering the banks and water below the bridge and informed the Select Board. The board contacted MDOT, and workers responded to investigate and to fix the navigation lights, which were not working, a problem Jason Kates had reported.
MDOT started the cleanup of the paint on the shore below the bridge, necessitating lane closures. They stopped when the recent snow covered the ground, but they will be back when the snow has melted and they can again see the paint. The paint is lead-based, and is being appropriately treated as an environmental hazard, so the crew doing the work were from an environmental cleanup company, supervised by an MDOT hydrological engineer. MDOT does not believe there is an immediate danger to our groundwater from the paint chips, but there (may be) danger to wildlife and the long-term health of the environment, so cleanup is a high priority. They will also be back in the spring to address the paint chips that fell into Back River below the bridge.
Our bridge was one of four which suffered this catastrophic paint failure. Three bridges in the Portland area also experienced the explosion of paint off the steel, but MDOT was able to clean those sites the first week. Interestingly, those bridges were also built in the early 1970s, though at this time no one knows if there is a connection in terms of the steel, paint, or other factors from 50 years ago.
The way the MDOT engineer explained the event, the paint and bridge steel were rapidly cooled as temperatures fell that Friday well below 0 F, but there was no failure at that time. The failure came when there was a rapid increase in temperature later in the weekend. The steel expanded, but the paint could not match the expansion rate of the steel and lost its ability to adhere, exploding off the metal and falling in pieces onto the riverbanks and the river.