Copperopolis residents who drive to Tuolumne County for work could be in for a two-day headache come January.
That's when repairs are likely to begin on the narrow, two-land bridge that crosses Tulloch Reservoir south of Copperopolis.
Construction could close the O'Byrnes Ferry Road bridge for a couple of days, Calaveras County Public Works Director Bob Kawasaki said.
If the bridge closes, traffic would be detoured to Highway 4, east to Angels Camp, then south on Highway 49 to Sonora.
"That's why this is so important," Kawasaki said. "We can't lose that bridge."
The thought of such a detour makes Kenny Calhoun, spokesman for the Sierra Conservation Center near Jamestown, cringe.
Calhoun estimates 50 employees from the Copperopolis and Stockton areas rely on the bridge for their daily commute.
About five months ago, people began complaining to public works about "banging noises" they heard when crossing the bridge, Kawasaki said.
The county found that several expansion joints which support the bridge were clogged up largely with bat guano preventing the joints from expanding and contracting with changing weather.
Because the joints are out of sync, traffic puts more stress on the bridge. The concrete slab that connects the bridge to the road is chipping, and the rubber boot the slab rests on has moved.
Kawasaki said the bridge isn't dangerous, but "it will only get worse in the future."
For the last three months, the slab has been reinforced by 1-inch-thick steel plates.
Construction costs have yet to be determined. Kawasaki said it could run anywhere from $40,000 to $80,000 to clean out the joints and repair the slab and boot.
The new joints will be filled with a rubberized asphalt, allowing them to move without getting plugged up again.