jueves, 29 de agosto de 2013

How do you make a building disappear

The New York Times's Henry Fountain describes two unconventional demolition methods pioneered by the Japanese.

Self-study activity:
Watch the video and say whether the statements below are true or false.

The activity is suitable for intermediate 2 students.



1 Henry travelled to Tokyo to watch the demolition of a 14-storey hotel.
2 Implotion is a very popular type of demolition.
3 Demolitions are difficult in areas where there are a lot of buildings close together.
4 Implosion involves using wrecking balls and/or explosives.
5 Tall buildings were forbidden in Tokyo as a result of the 1932 earthquake.
6 Today's ceilings are similar to those in the 60's.
7 In Tokyo, whenever they get rid of a building the first thing that goes away is the roof.
8 The second demolition method mentioned is like making a building the other way round.
9 The demolition work with this second method starts from the roof.
10  The Singer Building holds a world record.

How do you tear down a skyscraper? Well, as the old punch line has it, very carefully. But on the cover of Science Times this week, science reporter Henry Fountain makes it clear that it’s not just a matter of our being careful. Henry travelled to Tokyo to watch the demolition of a 40-storey hotel and is back to tell us about the science of creative destruction. So, hi, Henry.
Hi.
So how come they couldn’t just, you know, blow it up?
That’s what everybody wonders. Actually that kind of demolition which is usually referred to as implosion is only used in about 2% of the cases, number one. Number two, in a place like Tokyo as in a place like New York where buildings are closely packed, even a very carefully controlled demolition is a dangerous and risky thing, so it’s basically not allowed.
So no high explosives, no wrecking balls.
No wrecking balls either, because you need room to swing them and you never know what’s going to happen. Basically the idea is you have to keep things as controlled as possible. The most controlled way to do it is actually taking it apart bit by bit.
You point out in your story that they weren’t even allowed to build high rises until the 60’s.
Yeah I was sort of offshoot 1923 earthquake, the famous earthquake that nearly destroyed Tokyo for the next 40 years the building heights were limited to about a hundred feet but, you know, the economy took off. It started with the 1964 summer Olympics, actually, Tokyo hosted the Olympics. The economy took off, they started building and in lots and lots of buildings they built some hotels like this one. The ceiling heights nowadays are very sort of tight compared to sort of modern standards.
So what did they do?
So what makes it interesting is, because you know, cities occasionally have to tear down large buildings. In this case in Japan the environmental regulations and the recycling laws are such that they really wanted to keep it under control, so what they do in the case of the hotel is they kept the roof on. Ordinarily the first thing you do is get rid of the roof, and then they built a scaffold sort of hanging off the roof it hangs down about three floors, and the roof and scaffold were supported by these beams, these columns, they destroyed, demolished a couple of floors and then they lowered the whole sort of this cap that they built, the scaffold and roof they lowered it down over the course of about seven or eight hours, and then they started the next two floors. It’s kind of bit by bit taken apart, taking the building apart from the top up down, keeping it all, if you’re ever walked by everyday you wouldn’t really notice anything is going on. Over time you might think, hey that building is like, you know, half the size it used to be but it basically looks pretty normal.
You were in the hotel yourself while this was going on?
Yes.
What was that like?
I would spend most of the time down at the bottom where I talked to the engineers and stuff. Up top it’s a total chaotic scene with heavy equipment, you know, dust and grime and everything, and then it stops and they have these jacks that actually jack the roof down over as I said six or seven hours and then once the roof is back in place they work on the next two floors. The columns themselves are lowered down, so the whole thing is kind of leapfrogging in fact, it’s pretty cool.
It’s almost like a building project in a certain way.
Yeah, in reverse, sort of.
Yeah. You are… also describe a different kind of process and this one it just totally boggles the mind, demolishing a building from the ground up.
…from the ground up, yeah.
How does that work?
That’s also in Tokyo. That’s been done a couple of times and that really is like building in reverse. So what they do is the building they just finished in January was something like 300ft tall it had 40, it’s a steel structure, it had 40 columns. They cut each column about two feet at a time and they support them with these big hydraulic jacks that can support, you know, a thousand tons each, and they do in a sequence so that the building doesn’t kind of you know fall over while they’re doing it. They got it very planned out. Then they lower all the jacks that two feet or so all at the same time. They cut another two feet out of each one, lower it down until they get to do three or four of those before they get to the next floor. They demolish the floor, they repeat the whole thing again. So all the demolition work actually takes place on the ground, which means a couple of things. Number one, it’s generally safer, number two you can use bigger equipment, because you don’t have to raise, lift the equipment to the roof or to the top of the building.
Do we have a lot of obsolete skyspcrapers in the United States?
You know, we don’t have a lot. We actually we may have a few in New York. The people I have talked to seem to think tearing down a building is a big deal so the reality maybe you get half a dozen, maybe a dozen at the most buildings torn down, but still, you know, in New York we had the Deutschbank building torn down a couple of years ago and that was damaged in the World Trade Center attacks. We had the Coliseum, where the Time Warner building is now, but before that the biggest building and still the biggest building ever torn down anywhere was the Singer Building which was torn down in 1968. That was six hundred something feet tall. So, you know, we haven’t torn down very many big buildings so we may be, we may be seeing more of them.
Well, when it happens Henry Fountain will be here to tell us about it.
Yeah, I’ll try to stay out of the way.

Key:
1F 2F 3T 4F 5F 6F 7F 8T 9F 10T