Repairs to the Washington Monument will require massive scaffolding to be built around the 555-foot obelisk and may keep it closed until 2014 after it was damaged by an earthquake last year.
National Park Service spokeswoman Carol Johnson said Monday that a damage assessment found scaffolding is necessary to provide workers access to the top of the monument. Engineers determined most of the damage is above 475 feet on the structure.
The park service has put the $15 million project up for bid, with proposals due by July 31. Johnson says the agency hopes to award a contract and begin mobilizing in September. It will then take 12 to 18 months to complete the repairs.
The monument was the world's tallest man-made structure when it was completed in 1884.