“Truth? You can't handle the truth!”

[Jim_Campbell]

The precedents (yes, my spilling socks sometimes) show that buildings are constructed to withstand aircraft impacts. The Twin Towers were designed to withstand impacts from the biggest civilian aircraft of the day - the Jumbo Jet.

This isn't quite true. Channel 4 did a detailed examination of the collapse of the towers a few years ago and spoke to one of the primary architects, who explained that it never crossed their mind in their wildest imaginings that someone would fly a fully laden plane at full speed into the structure — their scenarios envisaged something like a passenger liner becoming lost in poor weather coming into JFK. In such a scenario, the plane would be travelling relatively slowly and, being at the end of its flight, be carrying a relatively small amount of fuel.

Cheers

Jim

[IndigoPrime]

Also, why would they send an unarmed plane?

Because they didn't have any armed ones ready.

The end result of 'ramming' it would be the same as that of shooting it down.

The interviews show it was all ad-hoc. They weren't sure what they were going to do. One suggestion was to take off a wing. The aim was to stop the plane hitting anything vital to the US (Capitol/White House, e.g.), not to safely bring it down.

Jim: I also remember a few pieces of insight into the manner in which the buildings collapsed, which stated it's all very logical. Starting with what you said, loads more fuel ended up in the mix, and then all it took was for one or two floors to fail. Then you've got a structure designed to hold up a certain weight having to hold up two or three times that. Then that falls. The floor underneath now has to cope with four. This becomes incremental all the way down, and happens very fast on reaching the point of no return.

So I don't see conspiracy either. I just see shitty people doing shitty things to create a shitty event. (I also recall around the time, some kind of report stating the intention was to create spectacle rather than bring the towers down. In a sense, they 'got lucky', in the most hideous nature of the word 'lucky'.)

[Skullmo]

This is a great demonstration of the thermal dynamics of tall structures, but I think the opening 20 seconds of voiceover are particularly relevant to the 9/11 industry. Fred Dibnah (1938-2004*)


* coincidence?

I wonder if there was any asbestos in that dust/smoke cloud that they were all breathing in!

[Spikes]

That was the 70's. People used to eat it for their dinner, back then. Never did them any harm.

[Frank]

This is a great demonstration of the thermal dynamics of tall structures, but I think the opening 20 seconds of voiceover are particularly relevant to the 9/11 industry. Fred Dibnah (1938-2004*)

I wonder if there was any asbestos in that dust/smoke cloud that they were all breathing in!

You saw the clothes those people were wearing, their haircuts, and the cars they were forced to drive. They were trapped in the eighties, Julius; death would have been a release.

[ZenArcade]

 Back then the poor had asbestos; now they have asbos. Z

[Hawkmumbler]

The temperature at which steel melts and the temperature at which steel bends are quite far apart.

I'm no scientist but if the steel only got hot enough to Bend then surely the Buildings would have swayed towards whichever side got hit, meaning the collapsing section would lean towards the impact; thereby making a "footprint" collapse pretty much impossible.*

Cheers

*As I said, I'm not a Scientist.

I believe the stair wells actualy distort hiw a building collapses. Being more structerly secure than the rest of the building they collapse last and some how change the direction it falls. Just something I heard on the radio and it's probably complete bollocks but felt I should give my two pence.

[TordelBack]

I trust everyone has their Structural Engineering MEngSc degree certs ready for inspection, unless of course you opted for Aeronautical Engineering with a follow-up certification in Accident Investigation? 'Cos it'd be really embarassing if all we have between us is school-level physics and an internet connection like wot I do.

[ZenArcade]

Ah Prof my physics is A Level and my internet down on the border at Clogher is low bit rate. It is just a dollop of common sense (I hope) that's guiding my thoughts here. Z

[The Legendary Shark]

In 1993 John Skilling, one of the WTC designers, told the Seattle Times that the buildings had been designed to withstand the impact of a laden 707: community.seattletimes.nwsource.com/archive/?date=19930227&slug=1687698
.
I guess Channel 4 got it wrong - or decided to do a little revision - or didn't do their research - or something.

[TordelBack]

Common sense, that most uncommon of senses.  I suppose my point is that we're all woefully unqualified to contest each other's interpretations, so all any of us are doing really is regurgitating anecdotes we've read or heard.  You either take it that the vast body of qualified experts know what they're talking about, or you don't - but both positions come from an ideological rather than an informed start point.  I'm disposed to defer to scientific expertise when I see a consenus - someone tells me 'this is how concrete-clad steel behaves under these stresses' I have no basis for a counter-argument - all I can do is look at their credentials and what their colleagues say, and decide if they are reliable.  Me arguing about melting-points and failure-stresses is just preposterous, and with genuine respect, that goes for all of us.

Doesn't mean it can't be fun, or informative, mind.

[Jim_Campbell]

In 1993 John Skilling, one of the WTC designers, told the Seattle Times that the buildings had been designed to withstand the impact of a laden 707: community.seattletimes.nwsource.com/archive/?date=19930227&slug=1687698
.
I guess Channel 4 got it wrong - or decided to do a little revision - or didn't do their research - or something.

So, a 707, not a 747 as you previously claimed. And there is no statement in that link to suggest that they calculated the impact at full speed and with full fuel tanks.

Cheers

Jim

[TordelBack]

In 1993 John Skilling, one of the WTC designers, told the Seattle Times that the buildings had been designed to withstand the impact of a laden 707: community.seattletimes.nwsource.com/archive/?date=19930227&slug=1687698
.
I guess Channel 4 got it wrong - or decided to do a little revision - or didn't do their research - or something.

So, a 707, not a 747 as you previously claimed. And there is no statement in that link to suggest that they calculated the impact at full speed and with full fuel tanks.

Cheers

Jim

And perhaps more to the point who the hell has ever designed ANYTHING to withstand the impact of fully-laden 767s - even if they said they did when they submitted their competetively-costed design 40 years previously.

[ZenArcade]

Well put Prof: it is a discussion and to be fair some on here have science backgrounds and we are in varying degrees, educated and informed lay persons with access to varying levels of published data on the incident. Some here including myself have good ideological grounds for involvment in the debate in that ideologically I am opposed to the peddling of basic non truths about ghastly events. This is as ever with the greatest respect to my esteemed friend Shark. Z

[Richmond Clements]

I'm loathe to swim in the rivers of shit being spewed here, but the Popular Mechanics podcast did a pretty definitive debunking of all the nonsense being talked here a few years ago.
Can't do a link to it from here (on phone in pub) but you know how to use Google.