You blocks, you stones, you worse than senseless things!

August 25, 2007 11:06 AM

How to move an obelisk.
posted by carsonb (21 comments total)

See also this diary of a modern obelisk-raising in Egypt.

Related.
posted by carsonb at 11:06 AM on August 25, 2007

That's some damn fine technical writing and illustrating!
posted by Standeck at 11:18 AM on August 25, 2007

IIRC, they used similar techniques to raise the upper pylons on the Millau Viaduct.

Some random photos. I couldn't find any that show them actually tilting the pylons up from the road deck.

(The construction of this thing was not how you would expect, at all. They built the huge tower pylons, then built temporary huge tower pylons halfway between them. Then they slowly slid the road deck out from the land, over each of the pylons. Finally, they drove the upper pylons out onto the road deck, tilted them up, connected up the cable stays, and removed the temporary pylons.)
posted by smackfu at 11:36 AM on August 25, 2007

[This is fascinating]
posted by BitterOldPunk at 12:01 PM on August 25, 2007

Is this something I would have to not be Obelix's friend to understand?
posted by CautionToTheWind at 12:12 PM on August 25, 2007

Its a crime not to show high-res scans of these illustrations.
posted by damn dirty ape at 12:17 PM on August 25, 2007

Tony said...

There's a great story about this obelisk. According to legend, in order to ensure the workers would not be distracted, the Pope ordered that anyone who spoke while the obelisk was being moved would be put to death. As the obelisk was being raised, the friction caused the ropes to begin to smolder, but no one would utter a word. Finally, one brave man yelled "Fetch water! The ropes are burning!" The obelisk was saved and as a reward, the Pope decreed that the man would have the honor of serving Mass for the Pope on Ash Wednesday. The last living direct descendent of the man (reportedly), serves Ash Wednesday mass for the Pope to this day.

damn dirty ape: Its a crime not to show high-res scans of these illustrations.

Agreed. These are the best I could find; the other postings of these engravings online are tiny in comparison. I've been using the magnifier on my mouse to pore over them.
posted by carsonb at 12:29 PM on August 25, 2007

The diary is neat. I love seeing archeoengineering in action.
posted by absalom at 12:32 PM on August 25, 2007

In case you're wondering why the complicated lift systems. Stone is very strong in compression, which is why an obelisk stands up nicely, but is *very* weak in shear. If you just tried to lift it by one end, it will break -- indeed, just carving them out of the rock was often too much strain for them.

The trick is to make sure there's no shear force along the obelisk. Today, we'd tie the monument to a steel frame, and lift that. Back then, you didn't have anything rigid enough to keep the shear off the stone, and strong enough to support the stone, so you'd use these complicated lift systems to support as much of the stone as possible while you lifted it.
posted by eriko at 12:52 PM on August 25, 2007 [1 favorite]

"Acqua Alle Funi!": Fermilab's unofficial(?) motto.
posted by funkbrain at 1:29 PM on August 25, 2007 [1 favorite]

Thank you for that link, funkbrain.
posted by carsonb at 1:38 PM on August 25, 2007

In case you're wondering why the complicated lift systems. Stone is very strong in compression, which is why an obelisk stands up nicely, but is *very* weak in shear. If you just tried to lift it by one end, it will break -- indeed, just carving them out of the rock was often too much strain for them.

This is why it's so surprising to read in the first link that

As Christianity grew in popularity, the power of the Roman Empire waned, but at the same time, Rome became depopulated and economically troubled. Ancient monuments fell into disrepair and some, like the obelisk in the Circus of Nero, simply fell to the ground.

How could the obelisk have survived a fall?
posted by jamjam at 2:22 PM on August 25, 2007

This takes me back to an impressive exhibit at the Smithsonian. Science and the Artist's Book, especially Edward Hutchins' offering, has stuck with me for several years:

However laborious it is to move an object as massive as the Vatican obelisk, Edward Hutchins believes it can be more difficult to change someone's mind. Fontana moved the obelisk with ingenious mechanics and hard labor, but to change a person's mind Hutchins subtly attempts to alter mental mechanisms, prejudices, and old habits.

Thanks for this carsonb
posted by jaronson at 2:39 PM on August 25, 2007

Somewhat more prosaic obelisk moving.
posted by progosk at 3:13 PM on August 25, 2007

very cool, but what damn dirty ape said.
posted by vronsky at 3:14 PM on August 25, 2007

Quoting from a comment at my site by Tony:

"There's a great story about this obelisk. According to legend, in order to ensure the workers would not be distracted, the Pope ordered that anyone who spoke while the obelisk was being moved would be put to death. As the obelisk was being raised, the friction caused the ropes to begin to smolder, but no one would utter a word. Finally, one brave man yelled "Fetch water! The ropes are burning!" The obelisk was saved and as a reward, the Pope decreed that the man would have the honor of serving Mass for the Pope on Ash Wednesday. The last living direct descendent of the man (reportedly), serves Ash Wednesday mass for the Pope to this day."

An easier way to see all the illustrations is via NYPL. (also at Octavo)
posted by peacay at 5:16 PM on August 25, 2007

Oh shit...heh. Redundancy. *I will properly read all the comments before commenting*
posted by peacay at 5:18 PM on August 25, 2007

peacay: Scroll down on funkbrain's "Acqua Alle Funi!" link for a slightly different take on Tony's story. Also, the NYPL scans are tiny. It's easy to see all the engravings at the purl.pt site; just click on the "grav" links.
posted by carsonb at 5:22 PM on August 25, 2007

With the passage of 500 years I'd say that's corroboration - I'm sure the details have morphed through the telling.
just click on the "grav"
Heh. Funnily enough, I knew that! I just meant that NYPL allows you to see all the thumbnail images at once. The copy at purl is very dark and hard to see at times - it was really quite difficult getting them to display well in smaller size. I seem to recall that Alex at Pruned also did a good job of tweaking out the ink artifact.
posted by peacay at 6:02 PM on August 25, 2007

Ah Nova. I really love you and the "secrets of ancient empires" series really rocks. But please, seriously, get real. The Egyptians took more than 10 days to figure this stuff out--why not let present day engineers do the same? Like, let them have time to try a full two different ideas maybe.
posted by DU at 6:46 PM on August 25, 2007

I really, really like this. Great finds!
posted by amyms at 8:29 PM on August 25, 2007