[Jason Weiser]

Originally Posted by The Dark

They did bore corings and then decided it made more sense to move the Bell to Mount Weather rather than try to build an H-Bomb-proof bunker in the middle of downtown Philadelphia with a system to raise and lower a one ton assembly of wood and metal (particularly since it's right next to Independence Hall, and any damage to that building would be unthinkable). Also, note that the vaults for the Constitution and Declaration are for normal safe-keeping; in case of a nuclear attack, they were to be evacuated to Mount Weather because those vaults are not rated for a nuclear strike on DC.

It actually is...how well it does depends on the size of the warhead...

http://nymag.com/daily/intelligencer...claration.html

Despite Ferriero’s best efforts to conceal the government’s plan from America’s citizens, a.k.a potential future zombies, we do have a pretty good idea of how the Charters would be protected in the event of a zombie outbreak.

Line of defense No. 1: the “Charters Vault.” In 1953, during the Cold War, a “Charters Vault” was built and installed at the National Archives. “At the closing of the building each night, the documents and their protective display cases were lowered into the vault,” according to Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940. “This was also done in the event of a nuclear attack.”

And more detail in the same article:

One of the most difficult challenges facing doomsday planners was deciding what cultural treasures should be saved … Between 1979 and 1981, a government task force called the Cultural Heritage Preservation Group met to draw up priority lists. The Library of Congress’s “Top Treasures Inventory” includes a Gutenberg Bible, the Gettysburg Address and various papers of James Madison, Thomas Jefferson and George Mason. For the National Archives, which is seven blocks from the White House, the single most precious item would be the Declaration of Independence, followed by the Constitution and the Bill of Rights. Though the National Archives building has a 55-ton steel-and-concrete vault on the premises, the scenario calls for the evacuation of these and other documents, probably by helicopter, to an underground facility, if there is adequate warning time.
According to Time, the art, at least — and presumably the Charters as well — would be sent to Mount Weather, a Virginia complex known to include a bunker that would serve as one of the sites the government would retreat to in the case of a nuclear strike. Whether this is still the plan, we can’t say for sure.

“When I was at the Archives in the eighties and first half of the nineties, we had a list of the highest-priority items (including the ‘Charters’) that would be protected in case of a national emergency,” Trudy Huskamp, a former Archivist of the United States from 1993 to 1995, e-mailed from the Marshall Islands. “I assume there is still such a list; however, I don’t know where the items would be relocated.”

So yeah, the vault was rated to survive a nuke, but the plan was not for the Charters to remain there. And to quote Howling Wilderness (p.34) (Yuck!)

As a side note, the National Archives was closed at the time of the attack. When the bomb destroyed the White House, the Constitution and the Declaration of Independence, the two most
important documents in American history, were in their normal nocturnal resting place: a 50-ton subterranean vault designed to protect them from fire, flood, earthquake, and (of course)
nuclear attack. In 1998 a special team recovered them and respectfully transported them to a similar vault in Mount Weather. With the Civgov evacuation, the vault was sealed with
concrete.