Will be updated.
The quintessential symbol of the St. Louis region, the Gateway Arch, has been under special scrutiny lately as rusty stains on its structure caused concerns.
The National Park Service has released a report from a Chicago engineering firm today saying that the stains are merely cosmetic and that the Arch is "as sound today as the day it was built." (It was completed in 1965 - and for the history lovers out there, here's a gallery of that process).
So what caused the stains?
The report states that the hypothesis of its engineers is that other metals got into the welds of the Arch, and it's those metals which caused the stains.
What's being done about it?
The Arch will get a good scrubbing and cleaning as part of a four-step process, complete with the possibility of the application of a clear coating of some sort. That process will also get rid of any graffiti scrawled on the Arch's base, and prevent any more from happening. (Fun fact: scrawling carvings on the Arch's surface is a federal offense).
The engineers said that the graffiti-covered areas have similar staining to that emanating from the welds.
A rappelling effort, similar to that done at the earthquake-damaged Washington Monument, might be necessary to clean the upper welds of the Arch, the National Park says.
“It’s a pretty challenging undertaking,” says Tom Bradley, Superintendent of the Jefferson National Expansion Monument Superintendent, which includes the Gateway Arch and its grounds. “The same who would do this recently did the Washington Monument after it had some problems. And compared to the Washington Monument, this is an extremely complex undertaking.”
Bradley says the plan is to get someone up the side of the Arch next fall, probably using a system of ropes, to pull additional samples and determine the best way to clean up the nearly 50-year old structure.
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