Alferd_Packer
Philosopher
- Joined
- Jul 3, 2007
- Messages
- 8,746
No, it is entirely pertinent to the topic that you posted. Your inability to see that only reinforces the fact that you really have no idea what I am talking about.
Your kung fu is weak.
And he replies!
????? Any opinions??
The Idiot said:As for your strong interest in a topic you can't even spell...
The Idiot said:After the plane strike the buildings were what's called a chaotic system.
How could I have inspected them if they sank? One was on fire for five days in port. Didn't sink. But plenty of deformations of steel structure - but no collapses!
And to keep it simple the structure consisted of only five structural column members - one core (subject to heat) and four outer walls (cooled by fresh air) - albeit kept together by floors. But I doubt very much that the floors sagged due to heat. Wishful thinking. I think most heat was vented away with the smoke and cooled by fresh air sucked in through all open windows.
It is a pity the core columns were not examined after the collapse.
Of course - but the structural analysis is the same.
I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire. Deformed, yes.
According to NIST no floors start to sag when the load redistribution occurs. NIST claims that only load redistribution on the columns - without any calculations - caused global collapse. I show that the load distribution is minimal - 6.25% of the mass above is shifted to and is carried by intact columns and that it cannot cause global collapse.
WTC2 is not a house of cards (where a very small load redistribution causes global collapse at acceleration = gravity)!
And what particular ship was this, and under what capacity were you able to access it?
Tell you what Heiwa, since you're so much better informed and.... well, just so much more clever than those whacky guys at NIST, why don't you write a technical paper setting out your arguments (try not to put 'I think' in there too many times though) and then send it out to every Structural Engineering Journal and society in the world (email is a wonderful thing).
I assume that you also belong to a professional association, so no doubt they would be very interested in what one of their members has to say about one of the most traumatic events of the last 50 years.
You gonna do it?
And don't forget to fill us all in on this unique expereince of yours.
I am a structural engineer specialized in shipbuilding. I have inspected many ships built of steel damaged by fire and overload of various kinds. None of these ships or their structures has ever collapsed by fire. Deformed, yes. I have some observations regarding the WTC2 collapse that may be of interest:
Are you honestly an engineer? Because with the above comments I don't believe you.
The floors did sag. There are plenty of photographs in the NIST report in which they can clearly be seen sagging. I can also cite other building fires in which floors (with much larger steel components) also sagged.
The heat on the exterior columns is irrelevant, because the exterior column failure was caused mechanically, not through heat. Again, there is ample documented evidence of the exterior wall bowing inwards.
Finally, upon initial wall failure the building twisted. A twist of the building any more than a couple of inches would pull every single support column off alignment, thus meaning there was nothing holding the upper structure.
Finally, can you, or can you not appreciate how a fire in a ship and a fire in a badly damaged 110 storey skyscraper are entirely unrelated, and in no way whatsoever comparable?
If you cannot appreciate this, you are not a structural engineer.
-Gumboot
Really ?
Well I guess we work in the same industry. I really am an offshore engineer. I really do work on steel platforms and I really do know the dangers that comes with fires offshore. It as alrerady been pointed the dangers of fires offshore, but I guess you being a structural engineer who specialized in shipbuilding would know all about this wouldn't you ?
Ever heard of Piper Alpha ? Gee that collpased after explosions and fires also. As you know it laid down a whole host of offshore safety features, but then again I guess you know all about them don't you ?
In fact my new found friend I am actually on a ship, that you probably designed, working offshore right now, so hey I guess we have quite a bit in common don't we?You being an structural engineer will be able to tell me all about safety on this vessel won't you ?
Welcome to JREF.
The structural analysis of a ship is the same as for a 110 story building?
Well done. Any other gems?
It would appear that some floors sagged on the WCT2 east wall due to the initial impact and that then no more floors sagged. And the tower was standing. There is no evidence that the floors later started to sag or became disconnected from the columns due to heat. This is just an invention of NIST without evidence.
The floor connections to the outer columns can be seen intact on the south wall around the hole, the north wall and the west wall. Most windows were broken so the heat could easily escape with the smoke.
The floor connections to the core columns are not known but the core columns were supported by floors all round except at lift trunks and stairways, but there the columns were interconnected by vertical supports, etc. so I do not believe that the floors sagged in the core.
And of course - even a sagged floor provides support as long as it is connected to the columns.
The floors, BTW, were not subject to much load! What does NIST say - 20 kgs/m² of furniture. So the floors could only sag due to its own weight and it can never pull apart the connections to the columns.
I agree that the floors on the east wall were disconnected due to the initial impact and that the east wall apparently buckled inward due to that and that then load re-distribution occurred as I (but not NIST) have explained. But it would not cause global collapse. The load on the intact columns are just increased marginally!
It is a pity that the forensic examination of the core columns was so sloppy = non-existing.
To assume that all 600 + truss/floors connections to the columns suddenly burst due to heat (and load re-distribution?) in the damaged area is preposterous as the load on the trusses/floors was minimal and could not rip apart the connections, even if heated. But the outer walls were not particularly heated as they were cooled by the brisk breeze blowing outside.
And what was the temperature inside? It appears NYFD staff arrived to damaged floors through the core area and reported some minor, isolated fires, easy to handle.
They thus walked on the floors/trusses in the core area and observed no sagging there ... and that evidently the core columns were intact. I like that.
What disturbes me is the sudden collapse of the core. In my view it could only have been caused by controlled demolition.
Okay, first off... the NIST collapse theory quite clearly states, and indeed relies on, NO floor trusses becoming disconnected from the columns. Had that happened, collapse could not have happened.
Is that a fact ?You are right! I am now working in the offshore industry looking after structural maintenance of various units ... and also the initial designs where mistakes may occur, e.g. to enable people to later inspect all areas. I am quite good at spotting fractures in the structures and then to analyse them and the risks involved.
Can we really say this with certainty?
The floor trusses played a pivotal role in the stability of the towers. Had a floor assembly let go of the external columns and crashed down on to the floor below, overloading that which in turn failed at the connections with the columns, then we could have seen a progressive collapse down to the ground.
It would be the continuing vertical loading on the now unrestrained columns which would cause them to move out of upright and ultimately come apart as gravity pulled them downwards.
ETA: Rather as breifly witnessed with the remains of the unrestrained core columns at the end of the main collapse
Is that a fact ?
yet you labour under the impression that offshore installations do not collapse due to fire. See this is the issue I have with you, you claim to be a structural engineer who is all clued in about structural failures offshore yet you have not learnt a thing from the collapse of the WTCs.
I like to think that when some guy is making safety recommendations offshore that directly effect me and my colleges, that they actually understand what they are talking about. I like to think that they know and understand that steel structures do collapse when there is enough heat, oxygen and fuel. I think to think that they fully understand that the single biggest danger offshore is fire and that they don't dismiss it as a nuisance that mearly warps structures.
I also like to think that a structural engineer who is responsible for the maintained of offshore structures, which is actually not what you claimed first, you claimed you were a structural engineer who worked on ship design knows what he is about. So which offshore structures are you actually responsible for? I am curious as to exactly what you do offshore and exactly what your position is. hey maybe we could hook and talk about various offshore projects we have worked on , Thunderhorse maybe ? How about Spiderman ? I take you have been out here a while to hold such a prestigious position, after somebody who is responsible for the structural integrity of offshore installations is hardy a novice are they ?