The Washington Monument could remain closed into 2014 to make repairs from last August’s earthquake, National Park Service officials said.
The work will require the monument to be shrouded in full scaffolding while crews repair stone damaged in the magnitude-5.8 earthquake that rattled much of the East Coast.
Carol Johnson, spokeswoman for the National Park Service, said the service hopes to award a contract for the $15 million project and get mobilized by this September. The work is expected to take 12 to 18 months, so it could finish as early as the fall of 2013 or as late as 2014.
After a full assessment was done of the structure, Ms. Johnson said, the amount and type of damage was entirely expected. The quake cracked stones in the uppermost point of the structure and shook loose pieces of its marble interior. Most of the damage occurred above 475 feet on the 555-foot structure.
Ms. Johnson said crews already have fixed the severely damaged elevator that carried tourists to the observation deck.
The monument has been closed since the earthquake, and agency officials have said the damage likely would have been worse if not for a $5 million restoration in 1998.
Installation of the scaffolding will require the removal of most or all of the plaza, flags and stone benches around the monument. Officials hope to use a decorative cover on the scaffolding, similar to the scaffolding used during the 2000 restoration project.
Some of the repairs will include removal of loose stone fragments, repointing of mortar joints, reinstallation of the lightning protection system and installation of masonry anchors to strengthen the stones.
A temporary road will be installed to provide access to the construction site, and pedestrians will be directed to the existing sidewalk along Independence Avenue.
Philanthropist David M. Rubenstein, co-founder of the Carlyle Group investment firm, pledged $7.5 million in January to help repair the monument. The gift will be matched by a $7.5 million grant from the federal government.
The exterior survey last fall attracted international media attention as a team of high-climbing engineers rappelled the outside of the monument to check for damage.
Plans for the repair project can be viewed by the public on the National Park Service’s planning website. The plans are open for public comment until Aug. 8.