Boling Bridge on Dawsonville Highway will close for up to eight weekends this fall as workers repair beams across the structure.

The bridge will close from 8 p.m. Friday to 5 a.m. Monday on the weekends starting as early as September, said Teri Pope, GDOT spokeswoman. On Friday, the Georgia Department of Transportation awarded the bridge maintenance project to Massana Construction, a company based in Tyrone.

The project will cost nearly $586,000 and will repair the overhead truss system — the large green beams — on the bridge. The beams are severely bent because of vehicles such as bucket trucks and cranes hitting them again and again, year after year, Pope said.

“It’s something repeated that’s happened hundreds of times,” she said. “And the cumulative effect of that is that we need to work on the steel trusses.”

The bridge was erected in 1956, and though the driving surface has had some work done, the beams have never had any major maintenance work.

Drivers will have to take an alternate route, such as Ga. 369, as no vehicles will be able to cross the bridge.

“This is a major corridor, one of the few east-west crossings at the lake,” Pope said.

She said the average daily traffic counts for 2009 estimate 12,550 vehicles cross the bridge each day, though weekend counts would be lower.

The work on the beams requires equipment in both lanes. Workers will even be suspended in the air to complete some repairs. Pope said the project could be done in fewer than eight weekends, and it’s not likely workers will spend more than the time allotted. Overtime could be costly.

The contractor must pay $5,000 an hour for every hour past 5 a.m. Monday that the bridge is closed. If work extends more than eight weekends, the cost is $300,000 a weekend.

Massana is still working out its plans for the project, and Pope said work could not begin any earlier than September, as workers must be conscious of osprey that have made the bridge their part-time home.

The birds, which are federally protected under the Migratory Bird Treaty Act of 1918, have made their nests on the bridge. Pope said she’s seen one remnant nest over the east-bound lane and one full nest over the west-bound lane.

She said the birds are not native to Georgia, but some have found a home at Lake Lanier.

“Several years ago during hurricane season, they got blown inland and found Lake Lanier, and apparently they like it,” she said. “We’ve had several osprey make nests on the bridge.”

The osprey nesting season ends Aug. 31, Pope said, and work can begin after that date without disturbing the osprey population.

The completion date is Nov. 30, Pope said.