Robert A. Vogel, superintendent of the Park Service’s National Mall and Memorial Parks, said the project also may require the temporary removal of some of the plaza’s flagpoles and benches.
The marble and granite monument was extensively damaged by the 5.8 magnitude earthquake that struck the area last Aug. 23.
The structure, especially near the top, sustained cracks and loosened pieces of stone and mortar during the earthquake.
The monument, which is entered by about 600,000 visitors a year, has been closed since the quake struck. Officials had said it might be closed until next year, but they now say the complex work could stretch into 2014, “which is frustrating,” Vogel said.
He added that he was hoping there might be a construction cam so people could at least see what was going on during the work. Repairs should be underway by fall.
“It’s a pretty big project,” he said. “Just putting up the scaffolding is a huge undertaking and challenge for us.”
Tourism officials said Monday that visitors have been disappointed that the monument is closed, but that does not seem to have affected visits to the city.
A spokeswoman for Destination DC, the city’s official tourism corporation, said it was hard to measure such impact.
“D.C. is rich in stirring experiences and national monuments,” she said. “And we’re grateful that people are able to go up to the top of the old Post Office Building” for good views of the city.
“Nothing beats the view of the Washington Monument,” she said.
The monument repair project manager, Michael Morelli, said the Park Service issued a request for bids late last month and hopes to get proposals by July 31. Contracts should be awarded by next month.
Vogel said the exterior scaffolding is required because of the difficulty of working in the confined interior of the monument. But Morelli noted that some inside scaffolding will be needed for interior work near the top.
Large chunks of stone were shaken loose by the earthquake, and other unstable pieces were removed by inspectors in the weeks after to prevent debris from falling.
The removed pieces were saved, Morelli said, and engineers hope to fasten them back into place with stainless steel dowels.
Where stone is missing, a patch called a “dutchman” can be cut from extra monument stone the Park Service has in storage or from a quarry that has previously provided stone, Morelli said.
He said no stones need to be replaced, but about 50 patches will be required.
He said eight to 10 feet of the granite plaza pavers around the monument probably would have to be removed to pour the foundation for the scaffolding. The pavers would be saved and reset after the repairs are finished.
The scaffolding will be much like that used when the monument’s exterior was refurbished 12 years ago, Morelli said.
He added that the Park Service would like to have the same kind of decorative fabric that was designed by an architect for the scaffolding 12 years ago, if the agency can afford it.
He said the repairs also will include the installation of 31 metal brackets to better fasten some of the exterior slabs on the monument’s pyramidal top. Some of the stone lips, or “rib tips,” on which the slabs rest were cracked by the quake, and the slabs need to be more securely attached.
“Even though that panel’s on an angle, if you got another shake or something, you wouldn’t want that falling out and then falling down 500 feet to the ground,” Morelli said.
“Those stone panels weigh about 2,000 pounds,” he said. “You’d hate to see even a part of one fall out and start heading to the ground.”
He said the Park Service has a highly detailed assessment of the repairs that are needed: “Where every crack was found, what the damage was, what kind of crack it is.”
“It’s pretty intricate,” he said. “That’s what took us so long.”
The project will create a large construction site, with a crane probably required to install the scaffolding and an access road built to the monument from a staging area next to the Sylvan Theater, off Independence Avenue SW.
The project is being funded by the government and by a $7.5 million donation from local businessman and philanthropist David M. Rubenstein.
“It’s certainly a unique structure,” Morelli said. “It’s like the Statue of Liberty, a one of a kind thing. You’ve got to go see these at least once in your life.”