Demolition

July 15, 2008 12:49 PM

Kajima's floor-by-floor slow demolition is one of those rare things in life that leaves you truly speechless....After all, seeing the video of a 20-floor building submerging into the asphalt as if it was liquid is something that belongs to a sci-fi movie.

Kajima informally calls this the daruma-otoshi method, after the old Japanese game consisting of a daruma doll made of stacked pieces that players knock out one by one without toppling the doll.

posted by Pater Aletheias (30 comments total)

Awesome. I just the next iteration would be the Jenga method, where competing recyclers salvage parts from all parts of the building until the whole thing falls over and the losing recycler has to clear the mess.
posted by ewagoner at 12:55 PM on July 15, 2008 [1 favorite]

Wow.
posted by Artw at 12:59 PM on July 15, 2008

The amazing claim is that this process is faster than traditional demolition. I didn't realize that the clean-up phase after you blow up (or use a wrecking ball on) a building was so slow. Anyone know why the "computer controlled" columns (I love that completely meaningless phrase--it's so 50's sci-fi: "um, just how will we explain that they can pass through this metal door? Don't worry, we'll say that it's a 'computer-controlled' process!") get replaced or covered in some kind of wrapping as each floor gets within about a foot of the ground?
posted by yoink at 1:01 PM on July 15, 2008

If it's so great, why don't they build buildings that way? :)
posted by smackfu at 1:01 PM on July 15, 2008 [1 favorite]

I just the next iteration would be the Jenga method

I think the Tetris method would be more fun. Finish a floor and *poof* it's gone. Although if the demolition crew is anything like me they will accidentally create a bunch of empty gaps and end up giving up when it gets too high.
posted by burnmp3s at 1:05 PM on July 15, 2008

Wanted….
posted by homunculus at 1:13 PM on July 15, 2008 [2 favorites]

Anyone know why the "computer controlled" columns get replaced or covered in some kind of wrapping as each floor gets within about a foot of the ground?

Probably to protect the mechanism from the dust & debris created by the actual demolition process. Although I haven't seen this in person, I'm prepared to bet that the process is something like this:

1) floor to be demolished reaches ground level
2) curtain wall removed, temporary steel frame inserted through entire level
3) one existing column removed (or symmetrical sets)
4) computerized column raises up out of the ground to replace demolished column
5) other columns removed one after the other (or in symmetry) and replaced
6) once all columns are replaced, temporary steel frame removed
7) once steel frame removed, demolition begins in earnest
8) floor demolished
9) computerized columns lower, so next level comes down to ground
10) repeat

You can see a brief flash during the timelapse where the temporary steel frame is visible. The system is probably most useful with reinforced concrete structures since those are the ones that are most often dynamited. Steel buildings are already disassembled in many cases, although it's normally done top-down.

It's a clever system. I bet it's expensive though.
posted by aramaic at 1:24 PM on July 15, 2008

Maybe they're using airbags for the last foot, because they can get very low when emptied?
posted by smackfu at 1:26 PM on July 15, 2008

Pretty!
posted by Dizzy at 1:28 PM on July 15, 2008

seeing the video of a 20-floor building submerging into the asphalt as if it was liquid.

Yeah, this is cool, but that description was a bit much.
posted by cashman at 1:39 PM on July 15, 2008 [1 favorite]

They so should have stuck a big weather flame on the top of it. It would have looked just like a candle slowly melting.

Which, actually, would make a really neat art project.
posted by quin at 1:41 PM on July 15, 2008

So much for asbestos and other dangerous materials flying through the air via explosions and wrecking balls...and efficient too? That's blasphemy. :)
posted by captaindistracto at 1:50 PM on July 15, 2008

Is it just me, or has the number of building demolitions using explosives gone down in the U.S. since 9/11/01? Seems like I used to see one on TV every six months.
posted by strangeleftydoublethink at 1:55 PM on July 15, 2008

Kajima informally calls this the daruma-otoshi method

I guess they were tired of the Gojira method.
posted by Kabanos at 2:00 PM on July 15, 2008 [3 favorites]

Michael Bay does not approve. He'd never miss a chance for an explosion.
posted by ninjew at 2:08 PM on July 15, 2008

That is freakin' awesome....
posted by Debaser626 at 2:38 PM on July 15, 2008

I wonder why they could not demolish it floor by floor, from the top down
posted by fearfulsymmetry at 2:54 PM on July 15, 2008

^ prolly debris disposal going top-down is problematic
posted by yort at 3:16 PM on July 15, 2008

I would imagine that it's easier when dealing with the demo'ed materials if everything is on the ground. That way you can more easily bring large equipment like front end loaders to bear.

I suspect that this way is probably more labor intensive in the initial setup, but much cleaner in terms of dust and damage to neighboring buildings.
posted by quin at 3:17 PM on July 15, 2008

As the cost of raw materials and transportation continues to rise, I expect to see disassembly -- instead of demolition/destruction -- propogate towards smaller, and more complex, items. Good stuff!
posted by seanmpuckett at 3:28 PM on July 15, 2008

I think it is slightly mis-leading, blowing buildings up is almost surely going to be easier, faster and cheaper - gravity pulls it down and dump trucks haul it away. The problem is, it can't always be done because the building is too close to other buildings and/or people (toxic dust clouds). So they have to wreck it "by hand" from the top down (floor by floor) with wrecking balls and other labor intensive. This bottom-up method does seem safer/easier/cheaper since all the people and heavy equipment are on the ground.
posted by stbalbach at 3:52 PM on July 15, 2008

why don't they build buildings that way?

Good question. My guess is it's cheaper to build the steel framework using cranes and then add the layers (floors, walls, electric). But it opens the possibility of the "pre-fab" skyscraper, sort of like lego-blocks just patch together and push skyward. Pre-fab is generally more efficient (green) for a number of reasons.
posted by stbalbach at 3:58 PM on July 15, 2008

as if it was liquid.

Yeah, this is cool, but that description was a bit much.

Yeah, it should have been "as if it WERE liquid".
posted by DU at 5:19 PM on July 15, 2008 [1 favorite]

stbalbach, you need to also include the time it takes to (a) develop the explosives plan (months of work); (b) strip the interior of the building (more months of work); (c) wire the building with explosives (another good chunk of time); (d) set up all the debris control drapery & c (yet more time); (e) clean up the mess (more months of work).

By comparison, setting up a few temporary supports, knocking out the real support, dropping a hydraulic into the ground, and then rinsing and repeating 40x over is probably pretty quick.
posted by five fresh fish at 5:25 PM on July 15, 2008

Or in other words, while the actual time of destruction is mere moments with explosives, the time to prepare and time to clean up is measured in months.
posted by five fresh fish at 5:26 PM on July 15, 2008

Anyone know what the music was? I recognize some of it from the sample used in the song "Passing Me By" by The Pharcyde off of the 1994 album Bizarre Ride II the Pharcyde.
posted by sourwookie at 5:35 PM on July 15, 2008

where's the kaboom? there was supposed to be an earth shattering kaboom
posted by pyramid termite at 8:29 PM on July 15, 2008 [1 favorite]

Is it just me, or has the number of building demolitions using explosives gone down in the U.S. since 9/11/01? Seems like I used to see one on TV every six months.

The number has probably not gone down, but the circus atmosphere that used to surround the public display of that kind of destruction falls a little flat now.
posted by Enron Hubbard at 6:04 AM on July 16, 2008

If it's so great, why don't they build buildings that way? :)
It has been done! Building with the jackblock method was popular in the 70s. I can't find a good link, which indicates the method is'nt used anymore.
posted by Psychnic at 8:24 AM on July 16, 2008

I can't find a good link, which indicates the method isn't used anymore.

It's more commonly called "lift slab" construction. It's not used much because there are several ways for it to fail catastrophically during construction, which tends to kill whole bunches of people at once.

For example.

There were other accidents, and given the large safety concerns people tend to avoid the technique nowadays -- the things you have to do in order to stay safe make it less economical than standard construction.
posted by aramaic at 11:59 AM on July 16, 2008 [1 favorite]