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WTC construction manager speaks of the resilience of the twin towers

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posted on Dec, 29 2009 @ 08:47 PM
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Originally posted by esdad71
It is not NIST's job to find the why but to make sure it does not happen again.


How are they supposed to prevent something they don't even understand from happening again?


reply to post by the eyes have it !!
 


What you say contradicts official investigations, so if you really believe it then I guess you are calling for further investigation / a better investigation yourself.

The connections from the trusses to the core did not have the issue you are talking about, though, and a truss isn't going to just come loose at both ends simultaneously and "pancake" down for that reason.




posted on Dec, 30 2009 @ 08:39 PM
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Dampers

These dampers consisted of a flexible layer of patented rubber glued between two pieces of metal. These replaced the lower portion of selected trusses on all but 10 floors of both towers ! The temperature of the fire far exceeded the rating of the rubber. The sheer weight of the building above the initial failures started the collapse and the downward force of every floor collapsing, which also increased the weight, lead to failure of the next. Thus resulting in this pancaking effect and the peeling away of the exterior wall like a banana peel. These same dampers are also in many other buildings in North America but most are not tall and used a comparatively small number for earthquake specifications and codes. The Sears tower does have them but I have not looked into the Quantity. It is not surprising the report made no mention of this. If you go to one of the engineering forums found in Google results you will see where some engineers are in agreement on this!! Some of these dampers were also instrumented with LVDT's (low voltage distance transmitter) to measure movement of the dampers.



posted on Dec, 30 2009 @ 09:33 PM
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reply to post by the eyes have it !!
 





The "damping unit" illustrated above is what you are referring to, no?





That image shows the truss before the damper was even installed. There is obviously more holding it together.

And like I said, the core connections didn't have them. So no pancake.



posted on Dec, 31 2009 @ 09:58 AM
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How interesting that this forum is now under scrutiny ! I mean with all of the conspiracies floating around. The noticeable gap in the connection to the 3/8" plate preceding the damper seems strange. In my opinion of course. Not to imply it is incorrect. In a structure that is supported by the outer-shell, upon separation at that connection everything else becomes relevant, it would seem. I am not an engineer though. This will be my last post here. God Bless America !!!!



posted on Dec, 31 2009 @ 05:48 PM
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Originally posted by the eyes have it !!
In a structure that is supported by the outer-shell


50% perimeter columns, 50% core structure. When they are not equal, the core structure is taking the greater loads. If the truss connections fail to the perimeter columns because of a rubber damper, the connections to the core are still going to exist.




posted on Jan, 1 2010 @ 09:14 PM
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I should expand on my theory. First I had a type-o error there were 10,000 dampers in each tower not 1000 ! which comes to 100 per floor. The catastrophe of course was brought on by the impact of an airplane. My take on the dampers is that they are of no value in any area of high temperature and provide a weak point during compression when installed as such. When viewing the collapse of WTC #2 it is apparent that the failure begins at the floors of impact, the building above there remains intact and begins to list to one side and fragmentation and expulsion begins below the impact point when the upper portion makes contact with the lower. The problem with the reduced/consolidated core of these structures is upon impact and entry of the airplane close to center of the building the entire core is subjected to impact and fire. These cores also tapered off after floor 66 making the core sections above that more vulnerable to total impairment at impact. In this design the shell and the core are equally dependent on each other ! I believe the core was compromised by damage then heat and was first to fail in the collapse and the dampers assisted in the pancake effect which may have been a god-send verses the buildings toppling !

[edit on 1-1-2010 by the eyes have it !!]



posted on Jan, 1 2010 @ 11:15 PM
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reply to post by the eyes have it !!
 


Please explain, so we understand that you understand what you're saying, how thermal exchange works.

Then please explain how an hours worth of office fires, that effected roughly 10% of the entire building, could create enough thermal energy to heat up thousand of tons of construction steel to the point of instant failure?

Then, again, please explain how the collapses managed to stay symmetrical, and complete, in their failure from what you describe as a very chaotic mechanism. How did all the steel heat evenly, and fail at the same time, to allow a collapse that did not slow from resistance, or take the path of least resistance?

If ANY of the steel was not heated to failure then you would have resistance, which is obvious by the fact that the collapse wave was smooth and accelerated rather than slowed, there was none, resistance that is.

That's not even getting into details, just the obvious stuff, you have a lot more to think about before creating your hypothesis.

[edit on 1/1/2010 by ANOK]



posted on Jan, 3 2010 @ 10:47 AM
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These buildings utilized 40% less steel than conventional designs. And tons and tons of steel did fail. The buildings are gone dude.



posted on Jan, 3 2010 @ 10:51 AM
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reply to post by the eyes have it !!
 


The Construction Manager said " The buildings could stand up to multiple

plane crashes".

Multiple = plural

Plural = many



posted on Jan, 3 2010 @ 11:27 AM
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If there were explosions and damage to the lower core that would certainly weaken it. If you look at the aftermath of tornado's it displays the incredible grinding and pulverizing effect of tumbling material. I think that skyscrapers are more ego and money generating ideas than any common sense lends. I am against the imminent domain that displaced over 1000 shops also. The "Big Dig" in Boston that boasts the most expensive 1 mile of road on the planet was another plan to pile as many people on top of one another as possible and was loaded with personal petpork projects at taxpayer expense. Dense population and construction are a terrorists dreams. They could have filled every pothole in America with dollar bills with what was spent on the big dig. If I recall the engineers on this also said it could withstand the pressure of water and wouldn't leak. Oh how mans ego doth swell over time so as to make an easier target for mother nature to smack a little reality into the fallible human. I'll bet if 10 replicas of the WTC were all impacted with airplanes the results would vary.



posted on Jan, 3 2010 @ 11:28 AM
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reply to post by the eyes have it !!
 


That's about the only thing you'll find generally overall agreement on - the buildings are gone but there could be a few objectors to even that opinion


You noted earlier that the thread was under close observation but that applies to all threads in the 9/11 forum because things tend to get real nasty real fast between opposing parties here.

Interesting view you have there re the dampers but I'd imagine they had a limited range of damped motion with a hard limit on excessive travel in either direction which would have to be up to the rating of a solid connection at least. Their purpose was to damp out harmonic oscillations (eg in strong winds) which makes it even more important to note the statements by William Rodriguez about WTC1 swaying, swivelling excessively pretty much right up to the collapse of WTC2 - why weren't the dampers working?

Something else I've noticed after looking through hordes of photos taken of the rubble is that universally (apparently), the bolts securing the floor trusses etc to the inner columns and the outer columns are what failed - they all seem to have sheared. In stark contrast to that, the spandrels of outer column sections had quite a few bolts connectiing sections together and those seem to have survived to a larger degree with the actual steel showing tearing.

Just a bunch of physical clues to look at that might get us to the facts of how it all failed - don't stop looking for more.

EDIT - laptop keyboard is psycho


[edit on 3/1/2010 by Pilgrum]



posted on Jan, 3 2010 @ 11:54 AM
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This is from Link to artcile

Gives you an idea of the damping system that was used in the WTC.



Viscoelastic (VE) dampers are dependent on both relative velocity and displacement to dissipate energy. VE damping system in Twin Towers is a double-layer shear damper using a 3M material, which is a rubber derivative, glued to steel plate and angle irons. This material will carry some load (which is temperature-dependent and would be less than the two-bolt connection as shown) as it displaces. As installed it has several functions:
1. It develops continuity moment at the end of joist girder, that is, the joist girders will behave as partial continuous members under Dead and Live load. It is partially restrained under Wind load.
2. It restrained the lower chord of the joist girder (in the direction perpendicular to the plane of the joist). Therefore it stabilizes the concrete diaphragm. Note that for a 4-inch thick concrete slab spanning 60 feet, it would buckle if there were no joist girder. It also transfers compression load through bottom chord.
3. Joist girder-column connection is a moment connection.
4. It reduces the energy to be absorbed by the joist girder and the columns under Wind load.

As the temperature rises, 3M materials would loose its load carrying capacity, i.e. its energy-dissipating capacity. This is equivalent as loosing the two-bolt connection because it will act as though there is gaps between the steel plate and the angle irons. As a result, several things would occur:
1. The joist girder is no longer a continuous member. Therefore, even under Dead and Live load, its top chord would rotate more relatively to its supporting column.
2. All the compression or tension force to the diaphragm would go through the top chords only.
3. More rotation between the top chord and its respective column under Wind load.
4. No more lateral restraint for the bottom chord and the joist girder could buckle laterally and the slab diaphragm would follow.

And the result is a tremendous demand on the connection between the top chord and its supporting column.
Let be clear that the VE damping system is a novelty design. First of its kind in the World. First of its kind implemented in a skyscraper. The reason I still think it is a design flaw is that:
In the 60’s and beginning 70’s there are many literatures about plastic design in steel including ASCE manual No 41. From J Heyman to Beedle, they all emphasize the importance of collapse mechanism in Limit Analysis. And in dealing with inelastic behavior such as VE damping system is engaging in Limit Analysis whether you want it or not because you have to think what will happen beyond the device limit.




This is a good analysis of the damping system that was used in the WTC which was subject to high heat during the fires. It is something that is never really discussed but I guess I mad a mistake in thinking that most of you would have taken a look since there are some very knowledgeable posters in this forum to counter the trolling and one liners.

The building was created to balance the load as has been stated. It did. Upon initial impact it absorbed the impact and shook for several minutes and still stood. That in itself was a marvel. This confirms what the OP said, that it was designed to survive the impact.

However, the jet fuel ignited and was out of control on several floors. So, if there is a severed column that was holding a truss, as it is still held by the damping system, it would weaken in the heat and does not need to heat the steel to a melting point but simply also weakening. The load would then not be distributed and eventually it would collapse. This is basically what happened. There is no need to argue bunk science.



posted on Jan, 3 2010 @ 12:11 PM
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reply to post by esdad71
 


Thanks for the pertinent info

The obvious comment has to be that something like less than 1% of the dampers in the building were subjected to heating (or that's how it appears at least), yet the building behaved as if it had lost more like 99% of any damping.



posted on Jan, 3 2010 @ 12:37 PM
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reply to post by ANOK
 


It doesnt need to have every steel part heated to failure. As it has been seen before, total destruction of a structure can occur with the failure of just a few bolts or plates or beam. Recall the bridge collapse in MN a few years back? ONE little steel plate failed. That caused the entire strcuture to catastrophically collapse, appearing as if it was demoed. But it wasnt demoed. It just had ONE critical part fail, and the whole bridge came tumbling down. Thats just the way it is when it comes to engineering structures. Sure it maybe sturdy and so on, but sometimes, one bolt or plate or weld or dampener or whatever fail can fail, and the whole damn thing gives way.



posted on Jan, 3 2010 @ 12:45 PM
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Originally posted by GenRadek


It doesnt need to have every steel part heated to failure. As it has been seen before, total destruction of a structure can occur with the failure of just a few bolts or plates or beam.


And before 911 , which building have we "seen before" fall this way.

I missed that link I guess



posted on Jan, 3 2010 @ 01:14 PM
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reply to post by Sean48
 


There is a precedent for everything. The terrorists did not attack the buildings to cause fires and cause collapse. Just like the 93 bombing, they were attempting to knock one into another to bring them down. In my eyes they go lucky that day. Very lucky.

One from the north and one from the south and hopefully one of them would send enough into the other building and cause collapse. It did not happen. If it did, the loss of life would have been in the 10's of thousands.

Why can we not accept the fact that the buildings withstood the initial impact, AS DESIGNED, and allowed those who needed to escape get out of the building. If the design had been flawed, I feel that they would have toppled over upon impact. Resilience is not the ability to survive the fires but the ability to redistribute the initial impact and survive.



posted on Jan, 3 2010 @ 01:17 PM
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So, we have this alleged large and heavy aircraft impacting at over 500 MPH against the building's structural components, with a large explosion, NOT causing the building to collapse. However, about an hour later, heating of the building's structural components by oxygen starved fires causes a complete collapse?

If these buildings were to collapse, the initial impact and explosion had a much better chance of initiating such an event immediately after impact, than the subsequent oxygen starved fires.



posted on Jan, 3 2010 @ 01:18 PM
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reply to post by esdad71
 


Why can you not believe they survived the impact?

The Construction Manager said they could survive MULTIPLE planes

hitting them.

And WTC7 , no planes hit that



posted on Jan, 3 2010 @ 01:19 PM
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reply to post by GenRadek
 


Again with the irrelevant analogies.

A bridge does not have a path of 'most resistance' to collapse through, a bridge has nothing but open air for it collapse into.

With that and the stupid reply from the eyes have it, yes we know the buildings gone genius, shows you have no idea what you're talking about, and are just throwing ideas around as if they were fact hoping that they will stick.

You again are failing to understand PATH OF LEAST RESISTANCE. The same old story with you guys, ignorance of basic physics.

The towers did not only collapse they pulverized THEMSELVES as the collapse wave moved the building through the path of most resistance.

There was not enough damage to the columns, from office fires or plane damage, to overcome resistance in the whole system. The fires would have had to have engulfed the building completey, and even then sorry but we know from experience and history that even then steel buildings do not completely collapse through the path of most resistance.

If only ONE column, weld, bolt, whatever, did not fail instantly, creating resistance to the collapse, then the collapse would not be symmetrical. That is the nature of chaos. The collapses were 'controlled'.



posted on Jan, 3 2010 @ 01:24 PM
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Originally posted by the eyes have it !!
These buildings utilized 40% less steel than conventional designs


And that means...?

Steel is steel regardless of how much was used compared to 'conventional' designs. What is a 'conventional design' btw, do you know or did you just copy that from somewhere?

Yes the building is gone, you have incredible powers of observation...



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