after the world trade centre

World architecture... what's happening generally....

Postby James » Thu Oct 04, 2001 2:02 pm

In fairness to the WTC buildings - they actually performed very well (although that might seem difficult to appreciate under the calamitous circumstances involved) they maintained sufficient structural integrity to allow escape during the period of over an hour after each of the initial collisions which is quite impressive given the temperatures of 1000+ deg.

The real issue though would seem to be whether high buildings are 'escapable' in the event of a calamity - certainly the experience in the far east has not been encouraging.

As to the argument that low level buildings are equally vulnerable - this is quite simply incorrect - for example the pentagon buildings which accommodated a similar number of occupants suffered a reasonably low level of casualties by comparison to the WTC (125 V 5500 casualties).

High buildings cannot be made safe or escapable in the same way as low rise buildings. The WTC buildings performed far better than was to be expected however probably far better than contemporary structures would do under the same circumstances. Unfortunately, it still remains that tall buldings are pretty inescapable in such circumstances - at best fire can be contained and structural collapse minimised.

At 'breakneck' speed it takes a single individual 10 - 15 minutes to clear 35 floors through an open and clear stairwell - imagine that same stairwell filled with other occupants, shrouded in smoke, blocked by debris and that 10 - 15 minutes could turn into 30 - 60 minutes which is usually the outer limit of integrity in the case of fire.

So no answers then to the escape dilemma - Can structures be improved - hardly, in most cases even the most up to date technology finds it difficult enough to deal with 'normal' fires. When circumstances lead to a fire of 1000 deg it is almost impossible to guarantee performance. As to the specifics of such damage - it would not necessarliy take an airliner laden with fuel to generate such temperatures - a gas explosion or fireball within an air conditioning duct can generate similar temperatures over a very short period of time which none the less will cause serious damage.
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Postby rob » Thu Oct 04, 2001 9:34 pm

Well, at the end of the day I think its all going to come to the simple fact of why there were [skyscrapers] built in the first place. Do we want continuse urban sprawl vs. fear of skyscrapers and terrorist attacks? But do we want to built two great towers from the late '60s, or wouldn't we want something bold and new in the 21st century?

As me Dad says, America has to ask itself 'why?'
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Postby trace » Sat Oct 06, 2001 5:33 pm

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Postby trace » Sat Oct 06, 2001 5:52 pm

Very hard site to access, due to overloading by traffic and data transfer, but the pics are worth the effort:
http://www.geocities.com/twin09112001/disaster.html (generated by www.gallarotti.net)
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Postby trace » Mon Oct 15, 2001 9:32 am

Infrared mapping: Check out the multimedia link - Mapping the Surface of a Disaster - at http://www.nytimes.com/2001/09/23/nyregion/23TOPO.html
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Postby trace » Thu Nov 15, 2001 1:23 pm

Why Trade Center Towers Stood, Then Fell - http://www.nytimes.com/2001/11/11/nyregion/11COLL.html
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Postby Doug » Fri Mar 29, 2002 12:29 pm

Not such a stupid idea - used it myself in a final year design - though the lecturer was more concerned with high heels tearing the slide. Saw on US news and few days ago the principal now being put forward as a possible solution for escape for low rise buildings
Originally posted by rob:
Here's a stupid idea...

What about having emergency escapes like the have on airplanes, those bright yellow blown up jobs, of course they could be only on the lower floor, which makes it a bit useless, but after all i'm talking about stupid ideas.



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