Challenge: What is the specific mechanism of WTC7's collapse?

I went a bit further than looking at the hudson building, I went to the webpage of the company that did the job, and read their descriptions of various different demolition projects.

The interesting thing that is mentioned in almost all the accounts I read was "we did extensive planning because we had to minimize damage to x, y or z"..

If you don't care about the damage external to the structure you are bringing down, does it still require the same amount of finesse and the same number of charges?

E.g, if I build a table, one way I could do it would be to chop down a couple of trees, split the logs in half for the table top, and then stand it on some sections of logs for legs.

I could also build a Louis XIV reproduction Empire style dining table, complete with intricate inlaid designs.

Both things are still tables.. one has a great deal more craftsmanship and precision, but they're still tables.

If it's so easy for a building to collapse straight into its footprint by simply say, one charge per structural column at ground level, why isn't that done more often? Perhaps because the chance of external damage is greater if you don't pulverise floor by floor.

IF you don't care about external damage, then you are free to simply get out your ax and chop the tree down, so to speak.

Faster, easier, and also very easy to plan if you have time and blueprints in advance.

By the way, if anyone has a link for WTC 7 structure blueprints, I would love to see them, then I could come up with my own theories of collapse, based on newtonian mechanics.

NIST has the only docs about the blueprints that I have found for WTC 7.

I liked Slapnuts better.....

Originally posted by pavil
Temper temper....

I know exactly what Esdad is saying, I've been reading his confused posts for awhile now thanx. You can only take so much garbage before you get tired of trying to explain the very obvious, and very easy to understand, physics problems with the opinion he holds.

Yes you are wrong, WTC 1 has NOTHING to do with the collapse of WTC 7, which has been pointed out by numerous people here a gazillion times, yet Esdad and crew choose to ignore known science.

I can't say if it would have fallen with no fire or damage, I don't have inside info into what was going on inside the perps heads that day. But I can say with absolute certainty that damage to one side of a building, and fires, have never in the history of buildings ever cause one, or will ever cause one, to fall at near free-fall speed, with no resistance, into it's own footprint. Never, never, never, period!

It's a stupid argument based on ignorance of known physics.

I live just outside Detroit (hencforth: The D)...

I have been IN the Hudson's building prior to it's implosion.

THERE IS NO COMPARISON TO BE MADE.

Hudson's was TWELVE interconnected old school overbuilt badass brick and GIANT STEEL COLUMN buildings with delicate historical structures and an elevated train track right next door... NO COMPARISON.

From CDI:

The store was built in 12 separate stages, the first in 1911 and the last in 1946. The complex had two retail basements and 23 above grade retail floors, including mezzanines. Two additional basements and six upper stories in a tower, provided storage and mechanical support for the 2.2 million square foot building. In all there were 33 levels in the structure.
...
The demolition contract went to a joint venture between Detroit based Homrich, Inc. and Boston based North American Site Development. They, in turn, retained Controlled Demolition, Inc. (CDI) and the Loizeaux Family of Phoenix, Maryland to design and perform the tricky implosion of the Detroit landmark.
...
No structural drawings of the facility were available, making structural analysis and implosion design a considerable task for CDI. The interdependency of the 12 different construction stages, with differing construction and variable column flange directions and bay widths created what CDI calls differential natural failure modes in each section of the structure which CDI’s demolition program had to cope with. These factors created an implosion design, preparation and dynamic control challenge for the 2nd and 3rd generation of a family recognized as the international founders of the commercial implosion industry (see ENR cover story October 1972).

Hudson’s was bordered on four sides by streets filled with critical infrastructure and flanked on 3 sides by poorly maintained, turn-of-the-century structures with huge sand-cast glass windows that occasionally broke in high winds. Lastly, Detroit’s elevated "People Mover" paralleled the east face of the 439 ft. tall structure just 15 ft away.

Mark Loizeaux, President of CDI, called Hudson’s the greatest dynamic structural control challenge the company had ever faced. CDI had to sever the steel in the columns and create a delay system which could simultaneously control the failure of the building’s 12 different structural configurations, while trying to keep the hundreds of thousands of tons of debris within the 420 ft by 220 ft footprint of the structure. CDI needed structural data to complete its design. Under CDI direction, Homrich/NASDI’s 21 man crew needed three months to investigate the complex and four months to complete preparations for CDI’s implosion design. During that period, the lower two basements of the structure were filled with engineered fill and the perimeter basement walls bermed to 1st basement level with soil to support perimeter walls which would surely have failed under soil and hydrostatic loads once the horizontal support of the Hudson’s internal structure was removed by the implosion.

Double column rows installed in the structure between vertical construction phases, internal brick shear walls, x-bracing, 70 elevators and 10 stairwells created an extremely stiff frame. Columns weighing over 500 lb/ft, having up to 7.25 inch thick laminated steel flanges and 6 inch thick webs, defied commercially available shaped charge technology. CDI analyzed each column, determined the actual load it carried and then used cutting torches to scarf-off steel plates in order to use smaller shaped charges to cut the remaining steel. CDI wanted to keep the charges as small as possible to reduce air over pressure that could break windows in adjacent properties.

NO COMPARISON.

Diesel fuel fires can provide enough heat to cause the steel inside WTC 7 to weaken, especially during the time interval allowed from when the debris started the fire up til the collapse.

Plenty of time to weaken key components.

Guys, its been shown on this Messageboard way too often. Check out the photos of WTC 7, you can clearly see there's a lot of smoke coming off of the building (i.e. fire).

Originally posted by esdad71

The final figure for theoretical collapse acceleration rate of WTC7 in complete free fall in atmosphere and at sea level is 8.94m/s2, which is only a little above the actual observed 8.71m/s2 acceleration rate arrived at from analysis of the CBS footage and using the Emporis height measurement. From this we can imply that the structure provided a negative acceleration, i.e resistive force of approximately 0.23m/s2 to the gravitational collapse.

So this tells us that there was resistance, but you 'feel' it is not enough. Am I right?

No, it's not right. I know you looked damned hard to find something wrong with that page so you could feel better about it (you KNOW you were just itching to find something wrong with it as soon as you set out on it, right Esdad?), but the figures were actually slightly FASTER than free-fall, for the non-NIST figures. NIST should have more accurate information than a website about buildings because NIST has the actual structural information on WTC7.

OK, I can see your point. However, do you not agree that it would have been better if the calculation showed it fell faster than it should? That would prove that Physics cannot be applied.

You tell me. Because that was the case.

In your own words, this does "prove that Physics cannot be applied".


I know you're going to back-track on that now, Esdad, but checkmate.

And it wouldn't come down to a matter of "feeling" anyway. I think the page even has air resistance calculations, if I'm not mistaken. When you calculate air resistance (which CAN be found using physics), it would most definitely require the collapse to have been significantly slower. So, sorry, but you can't slip your way out of this with "truthiness".

[edit on 26-4-2007 by bsbray11]

Originally posted by Pootie
I live just outside Detroit (hencforth: The D)...

I have been IN the Hudson's building prior to it's implosion.

THERE IS NO COMPARISON TO BE MADE.

Hudson's was TWELVE interconnected old school overbuilt badass brick and GIANT STEEL COLUMN buildings with delicate historical structures and an elevated train track right next door... NO COMPARISON.


NO COMPARISON.

I agree, I was tempted to make that point too, but figured I'd go with one that wasn't at all open to mis-interpretation by those blinded by the trees..

Originally posted by Masisoar
Diesel fuel fires can provide enough heat to cause the steel inside WTC 7 to weaken, especially during the time interval allowed from when the debris started the fire up til the collapse.

Dude the diesel oil was recovered!!!! I'm not even gonna hold you guys hands anymore, go look it up...

Even if it did burn diesel oil does not get hot enough to weaken steel, no way no how. Go look that up too.

This whole time, I was simply masking myself of that which represents the anti-conspiracy movement.

It was a pleasure.

Thank you.

i have another point of interest.

NIST is supposedly investigating the bomb angle.

so, why are the 'debunkers' so adamant that no bombs were used? how do they 'KNOW' it fell naturally? NIST doesn't know how they fell. no one knows.

and yet, we will read over and over vague hand wavings about transfer trusses and fuel oil.

sorry, but TIME is an important factor in energy calculations, and in this case the TIME that the building's perimeter(before i hear about the penthouse, again) resisted collapse is ZERO. that's all four corners, not only kicking out at the same time, but continuing to kick out in perfect synchronization. at no point do the outer columns JOLT from hitting the ground, because THEY NEVER HIT THE GROUND. they are timed to explode before they get a chance.

the building offered no resistance to collapse.
SIMPLY not possible in this physical reality without an external energy source. (and not a kerosene stinking fire. it's a steel frickin' skyscraper, so overengineered, that it was possible to take out multiple floors.



[edit on 27-4-2007 by billybob]

Hi,

Could I please request a song… uhh I mean a dot point?

• Asymmetric damage and unevenly distributed fires cause symmetric collapse
  

[edit on 27-4-2007 by Yandros]

Hang on, hang on, I’ve got one

Ok what if:

The slurry wall moved, which it was later discovered to have done. And water got in under the building and caused its foundations to sink. Then … because of damage already done, and uneven sinking, the building broke apart and fell to pieces! Plus the diesel exploded making it *seem* like a controlled demolition.

Ha haaa, see how easy it is to make a bull# explanation for a building simply ceasing to exist? Anyone with half a brain cell can do it. But it doesn’t mean its correct, or even plausible, even if your understanding of physics is exceptionally poor you must understand that buildings are built out of steel for the specific reason that steel is STRONG. It doesn’t blow over in the wind, and it doesn’t turn into jelly at the slightest whiff of flame.

Originally posted by Masisoar
Diesel fuel fires can provide enough heat to cause the steel inside WTC 7 to weaken, especially during the time interval allowed from when the debris started the fire up til the collapse.

Plenty of time to weaken key components.

Guys, its been shown on this Messageboard way too often. Check out the photos of WTC 7, you can clearly see there's a lot of smoke coming off of the building (i.e. fire).

There was alot of smoke, you got that right. oh so this must mean there was a massive intense fire in there !! NO WRONG, that just shows that the "fire" was smoldering, so not really hot, actually just dying out by it's self.
Loads of smoke = Lack of oxygen = fire dying out

[edit on 27-4-2007 by WeSbO]

Originally posted by Masisoar
This whole time, I was simply masking myself of that which represents the anti-conspiracy movement.

It was a pleasure.

Thank you.

Had me scared there for a minute... I almos clicked the dreaded "foe" button on you...

Since no one has come up with anything other than the poster about the slurry wall. Which was a good attempt BTW. I'll try my hand in this challenge. When all things are equal, the obvious easiest mechanism is a form of controlled demolition (Occam's Razor), but I can't use that. So, with only damage, fire and gravity, I'll try my best. I know you are being sarcastic BsBray, when you say include calculations, but I'll reiterate that calculations are impossible without the structural drawings. So, when I include (______) that means the blank needs to be filled in by NIST, since they have the drawings, manpower and money.

Start with damage from the now collapsed tower. We now have an added cantelever load added to the remaining coulmns. How much is harder to determine than what I did with the towers. The difference being that the towers, (for simplification purposes) could be analysed by assumming a simply supported beam. With WTC 7, there were more than 2 column lines, thus making the structure an indeterminate structure and has to be analysed using structural analysis (______).

Ok, so, now we have the added load and moment. Then, we need to determine what the deflection of the columns would be due to this added load and moment. (_________). On a side note, the columns would all deflect the same degree because the building is a stiff structure (it's an engineering priciple).

After finding the deflection, we then would be able to determine the new eccentricity (offset from the centroid) of the total loads. Eccentricity adds an extra internal moment to members (that's why it is better to have just axial loads) (_________).

Then, we need to determine at what loss of strength the columns would buckle. And equate that to how long an office fire would take to reach that point. Again, (_________).

Now, to satisfy the bullet points (kinda).

Simultaneous failure of structure at all four corners of the building.

Simultaneous failure of all core columns except for one: the initial column failure under the penthouse.

If it is determined that the deflection, eccentricity and loss of strength were enough to cause the columns to buckle, the closest columns to the damage may buckle first (I'm assumming these would be the 78, 79 & 80 columns or whichever NIST said). That would be the penthouse collapse. The penthouse collapse would cause even more eccentrical loads and eventually global collapse.

No friction whatsoever during the global collapse, thus accounting for the free-fall acceleration.

Failures between exterior wall end-to-end connections without causing friction.

Lateral bracing of each column at each floor must be accounted for.

The only thing IMO that could account for this is the impact load of the building dropping. This is a very big stretch to get nearly every connection to dislodge, but it is not out of the relm of possibility.

Core columns telescoping down into themselves without friction.

This is a harder one to explain. For them to do this, they would need to buckle, then when the rest (undamaged part of column) hits the ground it would need to buckle again and again. Ultimately leaving what would look like an accordian shaped column and not nice little neat strips of columns that are all exactly the same length, appearing as though they were cut.

Anyway, there's my attempt. Where's NIST's?

Also, feel free to "debunk" because I already know there are holes in my attempt and it would help point them out.

Originally posted by WeSbO

Loads of smoke = Lack of oxygen = fire dying out

That's a bit misleading, Frodo.

And stretching it a bit from one conclusion to another.

Loads of smoke does not mean lack of oxygen as you are trying to say and it does not point to the fire dying out.

Now what I like to stand by when talking about 9/11 conspiracies is that:

Black smoke (sooty flame) = lots of carbon = bad fuel/air ratio = not efficient fire = not very hot fire.

I know some try to paint it off as saying that's proof the fires were dying off prior to both collapses, but when in actuality the situation mainly trying to be demonstrated by the smoke/fires is that they weren't as hot as the NIST wants to put them at, taking away from their stories of intensely hot office fires.

As for my attempt to explain what happened during the World Trade Center 7 is simply a mechanism of controlled demolition, simply because you're not going to have a nearly perfect collapse as such.

You had, like Bsbray11 said, a lot of simultaneous destruction of key support columns.

Odd? Yes.

If you're going to have a progressive collapse, you're going to have, in essence, have a partial collapse in this case. The fires weren't large enough to cause global damage to even just one floor. But you see a whole floor apparently give out (near the ground) and cause the rest of the building to give out.

For the columns to buckle or telecope, you're going to need a huge weight bearing load being placed on them and other weakened columns, which would be essentially across the whole board.

As shown in any video of WTC 7 you had the columns fail simultaneously across the board and then later producing the kink in the middle but that doesn't do much justice for people trying to support the Official Story.

The fall time was impeccable for that of a fire damaged building simply because it shows ( Hey! That fires really did a lot of damage!)

Did WTC 7 not have fire proofing?
Cannot steel withstand unconcentrated heat being applied to it?

The reason I say controlled demolition is because of the simultaneous failure, you didn't have one part of the building come down then the rest, you had the whole thing come down at the same time (like WTC 1 and 2).

What can cause such a loss of support frame for the building? Fires? Give me a break. It fell perfectly.

There's a point when you have to accept the possibility it was a controlled demolition because of the popularized key points.

Maybe WTC 1 and 2 isn't as easy to explain away but I'd rather put my money on WTC 7 being a CD. Velocity of its collapse and the fact that it was compromised so successfully is amazing.

Originally posted by Griff
I know you are being sarcastic BsBray, when you say include calculations

I'm not asking for calculations on this thread. I was showing Esdad something earlier, maybe that's what you mean.

For this thread, I posted that I don't expect/want all details to be worked out, but that the collapse should be explained in terms of how the internal structural components were behaving in relation to each other as the building was falling.

No friction whatsoever during the global collapse, thus accounting for the free-fall acceleration.

Failures between exterior wall end-to-end connections without causing friction.

Lateral bracing of each column at each floor must be accounted for.

The only thing IMO that could account for this is the impact load of the building dropping. This is a very big stretch to get nearly every connection to dislodge, but it is not out of the relm of possibility.

Griff, if those connections had any reasonable amount of strength to begin with, then what you're asking is out of the realm of possibility, because potential/kinetic energy would've HAD to have gone towards making them fail, and that costs energy.

There were no doubt hundreds of such connections, yet the building still accelerating at free-fall, indicating that the energy that compromised those connections was not being deducted from the kinetic energy of the building falling. In other words, a mechanism unrelated to the building's actual structure/force coming down was failing the connections.

This is a harder one to explain. For them to do this, they would need to buckle, then when the rest (undamaged part of column) hits the ground it would need to buckle again and again.

Both of which are energy sinks. For simplicity, assume that a buckle would only have to occur once per floor. That's still a massive energy sink per column, per floor, all of which would be deducted from the building's kinetic energy. Could not allow free-fall.

Anyway, there's my attempt. Where's NIST's?

I don't think they have the guts to suggest the same things in a formal report. Maybe they're just waiting for people to stop caring, as normally happens in these kinds of investigations? Ie, USS Maine, Gulf of Tonkin.

Originally posted by Yandros
Ok what if:

The slurry wall moved,

WTC7 was across the street from the rest of the complex, the slurry wall didn't go that far.

Ha haaa, see how easy it is to make a bull# explanation for a building simply ceasing to exist? Anyone with half a brain cell can do it. But it doesn’t mean its correct, or even plausible

Exactly, lol.

[edit on 27-4-2007 by bsbray11]

Dear bsbray:

I’ve been itching to post on this here thread of yours for a while. But being that what I have to say will appear (even) more ‘speculative’ than my normal postings and so it’s taken me some time to finally decide to write.

I’ve always been convinced that WTC-6 and 7 were nuked also (along with WTC-1 and 2). And the WTC-7 debris site showed the hottest temperatures on the NASA thermal imaging. 1341 deg F on 16-Sep-2001!

O.K., here goes. I suggest that the hydrogen bomb blasts were directed downward, into the ground, at WTC-7. In a fusion hydrogen bomb, 80% of the yield is high-energy neutrons and 15% is thermal blast (5% is other radiation). The ‘blast’ effects are what throw stuff around. And at the WTC-7 that didn’t happen. Instead the entire building got ‘sucked down and into itself’. Plenty of neutrons were certainly still reflected/directed upward and sideways to turn the structural mass into mush. But the main ‘thump’ went into the ground.

I always found the report strange and suspicious that the diesel fuel had been recovered from storage. Why would someone bother to report that? Call me paranoid but that never made any sense. Directing a nuclear fusion explosion into the sub-grade would explain the pyroclastic clouds at the base and why WTC-7 collapsed at possibly faster-than-freefall speeds.

Greetings,
The Wizard In The Woods

Explain to me how a mininuke is physically possible.

You need to reach critical mass. And a hydrogen bomb is even harder, you need a fission bomb to start it going, and its so uncontrollable that I think i would have wiped out half of NY.

This mininuke theory doesn't seem to have much merit at all. And besides, we have the test results on the dust, it was clearly thermate.

The only 'evidence' I have seen so far from the mininuke people is that there was still molten steel weeks later. But when you have a huge pit 5 stories deep full of insulating material, in which thousands of white hot thermate charges went off + a few larger bombs, I think its fair enough that molten steel would stay molten. Where’s the heat escaping to? Its not.