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There Is Something That Doesnt Make Sense To Me About Wtc Building 7's Collapse

Paul
post Dec 24 2010, 05:04 AM
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Ok here it goes guys i have been thinking about the collapse of wtc building 7 and what doesnt make sense to me is where did all the dust
come from just give me a minute to explain and maybe it will make more sense, just before building 7 collapsed it gave away internally
all the floors fell down internally gutting almost the entire building, now when building 7 start to collapse descend downwards there was an
enormous amount of smoke and dust that produced in my mind all this dust could only have been produced if all the floors where intact
well nearly all of them anyway, because as i understand it, it would take a great amount of falling mass and energy to produce this enormous dust
cloud and would require a great displacement of air in the atmosphere to produce the tremenous amount of air pressure that would be required to
move all of this dust around and of course producing the displacement and airpressure would require a tremendous amount of weight and energy
which to me could only occure if all the floors inside wtc 7 building where still intact when it desended suddenly downwards and could not come from
and empty shell of a building with a few standing columns remaining because the weight and energy would simply not be present which is required
to displace the air, so now lets assume the official story is true and wtc 7 did collapse due to fire and structural failure and the inside of the building
did collapse and cave in and building 7 descended just as an empty shell so where did all the energy come from to produce all of this airpressure?
Now we can see when the building just begins to collapse we see all of the smoke and dust begin to just arrise, not during the supposed intrenal failure do we see any dust arise so why does not this internal failure of the building produce any visible dust whatsoever? Maybe it is because there
is no puverisation going on, ever think about that? Now the other thing is how did the building and everything in it become pulverised to dust if it was just an internal failure surely the collapsing floors coming down from structural failure would not be able to produce enough energy in a crush
down type action as the builings descended to be able to crush the floors and all the buildings contents to dust, surely this must have happened as
the builind began to collapse from top to bottom with all the floors in the building still intact an some of the columns being blown out and cut only then would there be enough energy from the entire weight of the building and all of the intact floors would there be enough energy to crush the entire building and its contents to dust and only then would there be enough energy require to produce all that dust as result of the floors being crushed and pulverised to dust.

Maybe someone can explain to me how all of this dust was produced, if someone here cannot refute and debunk my theory then we have a big problem and the OCT is toast so now i anxiously await a response from someone here. Plz do explain.

Cheers Paul

whistle.gif whistle.gif whistle.gif
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DoYouEverWonder
post Dec 24 2010, 11:14 AM
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Even a small amount of concrete can make a lot of dust. Ever drive down a dry dirt road?

BTW: WTC 7 was a more typical bottom first demolition. WTC 7 was a very odd building because it was built over an existing building, the ConEd Substation for lower Manhattan. Which to begin with, doesn't sound like a good idea for a commercial office building. But in order to accomplish this, they used a system of cantilevered trusses from floors 5 - 7, to hold the building up. In order to drop the building, the first place to blow would be the 5th floor right under these trusses. That just happens to be the floor Hauer loaded with fuel and pressurized fuel lines that ran to a number of generators and day tanks scattered throughout the building.
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IslandPilot
post Dec 25 2010, 09:59 PM
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DYEW said:
QUOTE
i have been thinking about the collapse of wtc building 7 and what doesnt make sense to me is where did all the dust come from...?

QUOTE
because as i understand it, it would take a great amount of falling mass and energy to produce this enormous dust
cloud and would require a great displacement of air in the atmosphere to produce the tremenous amount of air pressure that would be required to
move all of this dust around and of course producing the displacement and airpressure would require a tremendous amount of weight and energy


QUOTE
all of the intact floors would there be enough energy to crush the entire building and its contents to dust and only then would there be enough energy require to produce all that dust as result of the floors being crushed and pulverised to dust.

Maybe someone can explain to me how all of this dust was produced, if someone here cannot refute and debunk my theory then we have a big problem and the OCT is toast


DYEW is asks a MOST CRITICAL QUESTION:
Where DID ALL THAT DUST COME FROM?

Was enough "potential energy" stored within the "Height" and "mass" of the WTC buildings for a "gravitional collapse" to cause a nearly complete "conversion" of those structures into DUST?!
A collapse by gravity would leave a big pile of rubble where a building once stood.
As DYEW indicates, if the buildings collapsed from "gravity", after column failures (even "explosive" ones), INTACT, nearly whole, FLOOR STRUCTURES would begin accelerating by gravity toward the ground....
When the momentum of HEAVY floor structures IMPACTS the nearly INFINATE RESISTANCE of the ground, is that ENOUGH ENERGY to break the concrete and steel floor structures apart, turning them into DUST? Definately Not, IMO.

The ground won't provide the INFINATE RESISTANCE and INSTANTAENOUS DECELERATION to ALL the falling floors, required to release enough ENERGY to turn them into DUST!

In a collapse by gravity, as one floor falls on top of another, there is a "rapid", yet "progressively prolonged" deceleration as upper floors start to impact the "progressively resistance" of floors beneath them.
The bottom floors would start "acting like a SHOCK ABSORBING SPONGE, "soaking up" some "gravitional energy" from the descending floors above. This should leave a big pile of rubble, 20 to 40 percent of the height of the orginal structure,.. with big chunks of concrete clinging to pieces of their steel reinforcements.

There is no evidence of a significant rubble pile associated with the destroyed WTC buildiings.
IN FACT, the "evidence" indicates substantial ADDITIONAL ENERGY was necessary to cause the "DUSTIFICATION" of building STRUCTURES, Long Before they MET any DECELERATING RESISTANCE from the ground!!

The "bulk" of building structures were "converted to dust" and NEVER IMPACTED THE GROUND!
The massive DUST CLOUDS billowing along the ground, and high into the air, are PROOF of this.

The minimal IMPACT DECELERATION RESISTANCE from the ground is a FACT, supported by "seismic" recordings from earthquake monitoring sites nearby. These sensitive instruments recorded "building impacts" similar to operation of nearby "jackhammers". A seismic impact level corresponding to the "collapse" of TWO MASSIVE One Hundred Story buildings was NOT RECORDED. (if needed, I'll provide a reference)

How does STEEL turn to DUST?!!
I know of no process that converts STEEL INTO DUST as we have seen in the pictures and videos.

Let me remind you that these buildings were constructed mainly from STEEL, GLASS, and aluminum; with a MINIMUM OF CONCRETE.
Concrete was not used or attached to the outer facade of the building.
Concrete was NOT USED in ANY of the columns supporting the building.
The exterior columns, as well as the "core" columns, were made entirely of STEEL!

The ONLY Concrete in the twin towers, was to cover and reinforce the floor "pans".
About six inches of light-weight concrete was used for the floors in those buildings.

Let's "DO SOME EZ Grade School MATH":
Six inches per floor x 107 floors (?) = 642 inches ... divided by 12 inches/foot = about 54 feet of "Solid Concrete floor "pans" should be left in a pile, if the "gravitational pancake colapse scenerio" is valid.

In other words, there are only FOUR floor's worth of "solid" concrete in the entire 107 floor building.

The TOTAL AMOUNT of CONCRETE was LESS THAN FOUR PERCENT of the whole BUILDING! How can only 4% of a building generate ALL THAT DUST?

Where did the buildings GO?!. Where is the RUBBLE PILE from a gravitional collapse? How much "energy beyond gravity" is needed to first PULVERIZE buildings into DUST, and THEN to LAUNCH that DUST UP INTO THE AIR, for the wind to carry downwind past the Statute of Liberty!?

That's still a mystery to me.
Stranger yet... How did the INSIDE of Building 6 "Collapse UPWARD into the SKY" (by Gravity?) to make such a big hole in the middle of it??

NEWTON has to be Madder than HELL by now, and ROLLING OVER IN HIS GRAVE! angry.gif

I see Obwon said something similar over a year ago:
http://pilotsfor911truth.org/forum/index.p...&p=10787197
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DoYouEverWonder
post Dec 25 2010, 11:30 PM
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QUOTE (IslandPilot @ Dec 25 2010, 08:59 PM) *
DYEW said:

Where DID ALL THAT DUST COME FROM?


How much dust are you talking about?

Did you measure the dust?

Was it more dust then you would expect from an explosive driven demolition?

Did you collect the dust? Did you test the dust? What did you find out?
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SanderO
post Dec 26 2010, 08:25 AM
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The floor height for the building was 13'. That's equal to 168". The floor slab thickness is about 4". So the ratio of mass to volume in the area of the floors outside the core = 4/168. That's 2.38%.

Inside the core it's a bit more complicated because you have lass floor areas (corridors) and lots of shafts. But this area does contain the columns. For example in WTC the cross sectional area of the core columns on floor 80 = 5080 square inches which equals 34 square feet. The core of WTC 1 is 137' x 87' = 11,919 sq ft. So the ratio of the column area to the floor are in the WTC 1 core is 34/11,919 = .29%.

In both cases you need to consider the wall etc and in the case of the wall they were metal stud with GWB surfaces and a similar calculation will show there is little volume of solid material added by the walls to the over all material volume of the building. And these were open office landscape floors. But let's be generous and say the walls added 1% of volume.

So the total mass volume by percentage would be

Floors = 2.38%
core columns = .29%
columns at facade = .29%
walls etc. = 1%

Total volume of materials of a high rise structure = 3.96%. The twin towers would have a similar density.

If you use this to calculate the entire size of the material stacked up on the foot print in the case wtc 7 which was about 47,000 square feet, the volume would be 610 x 3.96% which comes to 34' 8".

But of course some material was combusted and some was turned to dust. The floors by volume were 60% of the building mass. Let's say 20% of it was turned to dust and carried away in the air... that would reduce the pile to about 20' tall.

Of course we have building contents in the rubble and it was not close packed so there were air pockets and the steel could not be compressed into a solid mass. We might double the volume for air and voids in the rubble pile and then deduct a percentage since the pile spilled over onto the sidewalk and street.

So actually the rubble pile from a collapsed wtc 7 would be in the vicinity of 2 stories high... Shocking but true.

High rise buildings are mostly air!

This post has been edited by SanderO: Dec 26 2010, 10:57 AM
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lunk
post Dec 26 2010, 10:16 AM
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Reducing the volume of a 47 story skyscraper,
in just over 7 seconds, to a small pile of rubble,
is going to make lots of dust.

Free-fall speed, implies explosives,
and even more dust.
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SanderO
post Dec 26 2010, 11:05 AM
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WRC 7 was 610 feet tall. The entire collapse was not at free fall acceleration. There was a period of 2.25 seconds soon after motion was detected which would be about 100 feet of descent which appears to be at free fall acceleration. The rest of the collapse ...510 feet was not at free fall and was obviously not accelerating. The speed of descent after 2.25 seconds of free fall is about 80+' / second which would be about 60 mph (80-100'/sec). If this speed of collapse continued the rest of the descent would take 510'/ 100' sec = 5 seconds plus the 2.25 where it accelerated from 0 to 60+ mph would come to 7.25 seconds with the last 500 feet at the terminal velocity of 60+mph.
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DoYouEverWonder
post Dec 26 2010, 12:12 PM
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QUOTE (SanderO @ Dec 26 2010, 10:05 AM) *
WRC 7 was 610 feet tall. The entire collapse was not at free fall acceleration. There was a period of 2.25 seconds soon after motion was detected which would be about 100 feet of descent which appears to be at free fall acceleration. The rest of the collapse ...510 feet was not at free fall and was obviously not accelerating. The speed of descent after 2.25 seconds of free fall is about 80+' / second which would be about 60 mph (80-100'/sec). If this speed of collapse continued the rest of the descent would take 510'/ 100' sec = 5 seconds plus the 2.25 where it accelerated from 0 to 60+ mph would come to 7.25 seconds with the last 500 feet at the terminal velocity of 60+mph.

So?

Even if it wasn't free fall speed, it was close enough for government work.
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SanderO
post Dec 26 2010, 01:48 PM
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I provided this crude calculation so people could understand that when all three towers fell their decent was equivalent to the velocity that an object in free fall reaches after 2.25 seconds. Then the decent is not accelerating and in the case of the three towers was not decelerating... it was terminal and at about 100' per second.

If the speed was basically constant... after the acceleration period, the structure below was not slowing the collapse and the resistance of the lower sections floors was only sufficient to prevent acceleration, but not sufficient to slow or arrest the descent.

Unless all the floors were turned to "nothing"... and then nothing would be falling at any speed or rate of acceleration... the mass of falling floors and "building contents" was accreting... growing larger as it went down. This would make it seem that as the mass descended it provided a larger punch to the floor it came upon. And if this were true it would overcome the resistance of that floor - the same for every floor - in a shorter span of time. The analogy would be to how long it takes heavier and heavier hammer blows to penetrate the same density material. However I think that in the case of these floor collapses, the mass of impact was not necessarily the total of all the mass above as it was a disorganized descending avalanche of rubble. it's likely that the leading edge of the rubble carried a similar "punch" and met a similar resistance by the floor it impacted.

I don't think we understand the dynamics of such vertical avalanches very well. But there was no acceleration or deceleration so this is notable. It does not explain the 2.25 secs of free fall, but it does explain what we see after that and it does describe the descent of the lower sections of the twin towers which were NOT accelerating as the fell.
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lunk
post Dec 26 2010, 04:29 PM
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QUOTE (SanderO @ Dec 26 2010, 09:48 AM) *
I provided this crude calculation so people could understand that when all three towers fell their decent was equivalent to the velocity that an object in free fall reaches after 2.25 seconds. Then the decent is not accelerating and in the case of the three towers was not decelerating... it was terminal and at about 100' per second.

If the speed was basically constant... after the acceleration period, the structure below was not slowing the collapse and the resistance of the lower sections floors was only sufficient to prevent acceleration, but not sufficient to slow or arrest the descent.

Unless all the floors were turned to "nothing"... and then nothing would be falling at any speed or rate of acceleration... the mass of falling floors and "building contents" was accreting... growing larger as it went down. This would make it seem that as the mass descended it provided a larger punch to the floor it came upon. And if this were true it would overcome the resistance of that floor - the same for every floor - in a shorter span of time. The analogy would be to how long it takes heavier and heavier hammer blows to penetrate the same density material. However I think that in the case of these floor collapses, the mass of impact was not necessarily the total of all the mass above as it was a disorganized descending avalanche of rubble. it's likely that the leading edge of the rubble carried a similar "punch" and met a similar resistance by the floor it impacted.

I don't think we understand the dynamics of such vertical avalanches very well. But there was no acceleration or deceleration so this is notable. It does not explain the 2.25 secs of free fall, but it does explain what we see after that and it does describe the descent of the lower sections of the twin towers which were NOT accelerating as the fell.


If a tower 110 stories high,
collapses in about 10 seconds,
starting from a stand still,
isn't that acceleration?

Same with Building 7,
it started from a stand still and dropped,
into a pile below on the ground.

Going from 0 to 1 mile an hour, is acceleration.
Actually, a huge acceleration,
much more than going from 1 mile an hour to 2.

Free fall acceleration, is 10 meters per second per second.

Building 7 height 186 m
One would assume that as it collapsed,
more debris would slow it down.

There is always the greatest acceleration when something starts to drop.

So let's just count the first 4 seconds of visible collapse,
and building 7 should "fall" to about half its' height.

10+20+30+40=100m of drop, in the first 4 seconds of free fall.

Get out your stopwatches.

http://www.youtube.com/watch?v=edowrAzWQBo
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SanderO
post Dec 26 2010, 06:37 PM
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YES... there had to be acceleration in all three towers.

All three I believe accelerated to a terminal velocity of about 60+ mph. WTC7 seems to have accelerated at what is called free fall for 2.25 seconds or 32' per second... reaching the 60+ mph speed of descent and no faster.

The twin towers accelerated to the same speed but their acceleration.. to get up to that 60+ mph speed took longer... perhaps 4 seconds for WTC 1. Its acceleration was over 17 or so stories.

It's obviously hard to measure this because you need a fixed point which can be traced from top to bottom. That's not possible. We have to approximate unfortunately. But we are in the ball park since we no start and pretty much stop... and have some coherent data from the beginning of all the collapses.
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amazed!
post Dec 27 2010, 11:06 AM
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9 years later SanderO, does it really fooking matter?

The events were staged by powerful people within the government structure and elsewhere. The coverup is worse than the crime, and the vast bulk of the MSM participate in the coverup.

The rest of it is trivial pursuit. Fun to talk about, but essentially irrelevant in the big picture.
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SanderO
post Dec 27 2010, 12:15 PM
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Amazed,

This is a good point. But for many a case about the big picture, which is the "prize" is made from the bottom up by piling on the facts. I agree we can get bogged down in the details and many researchers are into the details.

Ultimately the crime will be solved WITH the details... connecting the dots so to speak. I agree and disagree with your point. As an architect I am concerned about getting the facts correct about the destruction of the WTC and even the pentagon... If we over reach we'll be off looking for the wrong perps in the wrong places and this may their tactic to cripple those who are on their trail. So stating the facts is important and getting them right as opposed to say the details don't matter is ultimately how the case will be solved and the people will be won over.
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lunk
post Dec 27 2010, 06:30 PM
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QUOTE (SanderO @ Dec 27 2010, 08:15 AM) *
Amazed,

This is a good point. But for many a case about the big picture, which is the "prize" is made from the bottom up by piling on the facts. I agree we can get bogged down in the details and many researchers are into the details.

Ultimately the crime will be solved WITH the details... connecting the dots so to speak. I agree and disagree with your point. As an architect I am concerned about getting the facts correct about the destruction of the WTC and even the pentagon... If we over reach we'll be off looking for the wrong perps in the wrong places and this may their tactic to cripple those who are on their trail. So stating the facts is important and getting them right as opposed to say the details don't matter is ultimately how the case will be solved and the people will be won over.


It was a controlled demolition, intended to bring it down, in its own footprint.
so, figure out where the demolitions would likely, have to be placed, well before hand, to accomplish this.
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paranoia
post Dec 27 2010, 08:06 PM
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a point of (hopefully small) contention: based on my observations, my interpretation is that wtc7 was demolished to fall into its footprint - and did so, but the 2 wtc towers actually fell farther away than what can be qualified as their own "footprints": the tops of the buildings fell furthest and the lower parts closest. its been awhile since ive seen it, but i recall seeing a post-demo overhead graphic of the wtc complex that showed (by outlining with circles) the radius of the debris and you could see that technically - the towers fell significantly further than their own footprints.

and you can obviously see the visual difference between buildings 1 & 2 falling vs. #7. the towers were trying to mimic or imitate a crush-down collapse (hence the raining down of concrete and related debris in a wide radius) while #7 allegedly buckled at some major structural point (but was actually rigged throughout for an almost "typical" demo) and was then basically crumbled into its own literal footprint.


edit: i guess we need to establish an exact definition for "footprint"...
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DoYouEverWonder
post Dec 27 2010, 09:28 PM
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QUOTE (paranoia @ Dec 27 2010, 07:06 PM) *
a point of (hopefully small) contention: based on my observations, my interpretation is that wtc7 was demolished to fall into its footprint - and did so, but the 2 wtc towers actually fell farther away than what can be qualified as their own "footprints": the tops of the buildings fell furthest and the lower parts closest. its been awhile since ive seen it, but i recall seeing a post-demo overhead graphic of the wtc complex that showed (by outlining with circles) the radius of the debris and you could see that technically - the towers fell significantly further than their own footprints.

and you can obviously see the visual difference between buildings 1 & 2 falling vs. #7. the towers were trying to mimic or imitate a crush-down collapse (hence the raining down of concrete and related debris in a wide radius) while #7 allegedly buckled at some major structural point (but was actually rigged throughout for an almost "typical" demo) and was then basically crumbled into its own literal footprint.


edit: i guess we need to establish an exact definition for "footprint"...

According to most property appraisers, the footprint of a building is the physical space that the building sits on. The area around the building, would be outside of the footprint.

Your observations are correct. WTC 7 because of its height and construction was a more typical CD and fell mostly within it's own footprint. The Towers because of their height and construction was an atypical CD and top third of the buildings were destroyed first, then the middle and then the bottom. Most of the debris fell outside of the footprint and was spread all over the 16 acre complex.
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SanderO
post Dec 28 2010, 07:36 AM
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Do You that's not entirely true. All three towers had column free office space outside the core which is not typical office construction. WTC 7 was complicated by the core having to be built over the Con ED substation which require a multi story cantilever truss to carry some of the core columns from above which could not be continued straight down to the foundation. And of course WTC 7 used long spandrels to support the outside ends of the floors with a non structural curtain wall attached to the same spandrel whereas the twin towers had a structural load bearing exterior wall of closely spaced columns assembled in staggered 3 column 3 floor assemblies.

The material which feel outside the 208x208 footprint was largely the facade columns/panels and some of the core which tipped over and fell outside the core. And of course there was a fair amount of the alumninuim skin that sprung off the facade and it too landed outside the foot print.

In all three collapses the floor systems which were crushed in the collapse and was about 3 stories of material did land roughly within the footprint.. but it did spread around. There was material from the inside of the twin towers which was forced out by the compressed air ahead of the collapsing floors. This material became the debris plume/canopy which was about 500' in diameter, but was surely not most of the interior. It was glass from windows, GWB walls, furniture, ceiling tiles and so forth carried out in the blast of air.

In WTC 7 the core seems to have been destroyed in advance of the collapse which IS similar to most CDs and this pulled the floors inward, the girders, beams, and spandrels supporting them inward and even the center of the facade opposite the core which is seen as the kink in the facade. This inward pulling caused the building collapse to fold in or "implode" and confined the debris pile considerably.

WTC 1 and 2 were slightly different. The north tower had its 17 stories collapse or be destroyed first with the destruiction beginning at the 93 floor causing the top section to drop, then the 94th floor was destroyed and so on until there was nothing left of the top. This took about 4 seconds. The who collapse began with the huge 400 foot antenna tipping and then dropping inside the core. Once the entire top was "gone" (it really ended up mostly on the upper floor(s) of the lower section, the lower section then collapsed. The descent of the top accelerated to over 60 MPH and and large sections of the facade were peeled off as the floors inside collapse past them. Much of the core columns remained after the floor collapse to to 50 stories or 600 feet high, but they broke apart, buckled and feel straight down. A couple of them tipped over to the East and outside the footprint.

WTC 2's collapse began when the 30 story section at the top began tilting to the SE where the most damage from the plane strike had been. Whatever caused further weakening left the entire 30 story upper section supported on fewer and fewer columns and they buckled and as they did the top tilted. As it did the SE floors and facade columns collided with the SE floors and facade of the top of the lower section. The tipping and dropping caused the top's lower section to dig further and further into the lower section. It was in free fall for a second or two as it tilted, but then when it the collisions of the two structures increased the shockwave destroyed the upper section. It couldn't fall in free fall through the lower section... it broke apart. Some of its debrid continued over the SE side and landed outside the foot print. Most of it came down inside and initiated the lower sections collapse which was similar to what we saw in the north tower... a rapid top down destruction of the floors and a peeling of the facade and stripping of the lateral support from the core.

The top of WTC 1 was similar in appearance to a typical CD, but the bottom part was a top down mass driven gravitational collapse.

Fire did not cause the tops to come crashing down and neither did the plane strike. WTC 1 was hit on the north side and it actually had its top tilt to the east before it fell/collapsed so this means the plane damage likely did not cause the tops' descent. The plane strike in the South tower may have contributed to the collapse, but wasn't the sole cause.
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tnemelckram
post Dec 29 2010, 02:57 AM
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Hi All!

I support SanderO's efforts to develop a new and radically different theory to explain the mechanism of destruction for each of the three WTC;s. I think he is sometimes misunderstood. He is not saying that no explosives were involved. He is saying that with very limited but well placed explosive initiation or assistance, gravity could then be counted on to do the vast majority of the destructive "work" required to produce the observed results, including the almost total concrete pulverization into dust and breakdown of the assembled steel components into very small pieces. On another thread he said 5% explosives and 95% gravity. FWIW, I still think explosives did at least 50% of that "work"(1).

He has convinced me to loosen my grip on my opinion. First, unlike him I have no relevant education or training, so my seat of the pants estimate has to be tempered by due respect for his expertise. Second, what he says has some interesting and favorable implications.

(I) It seems logical that any CD, legitimate or nefarious, would use gravity as the primary driver of the "work". That is what you see when you watch any of them. Gravity is well understood, predictable, benign, and always instantly available for free - unlike explosives, which present many variables that need to be planned for and controlled, are inherently dangerous, and are expensive to acquire and rig. So it makes sense that any CD would not just make maximum use of gravity, it would primarily rely on it.

(II) Given prior experience with thousands of legitimate CDs, the 911 plotters would know that they too can rely primarily on gravity. They just have to initiate and/or assist it; then it will do most of the work.

(III) The argument that the Laws Of Physics didn't change on 911 applies to everyone and everything, including plotter's plans for three nefarious CD's. There is no good reason for them to want, or us to expect, a really big boom just because it's 911, when they can achieve the same murderous result using the same gravity/explosive ratio that conventional CDs use.

(IV) The plotters want a CD that can be blamed on something else - specifically, the well observed air crash trauma to one part of the structure, and they want it to look like that caused the collapse. Explosions are obvious things, and the first and best way to disguise explosive use is to use less of them. The effect of looking like the plane impacts are to blame can be achieved by initiating the collapse with a larger number of simultaneous smaller powered charges on the ten or so floors surrounding the damage. Then you immediately assist Mr. Gravity with a limited number of very powerful, well placed and timed charges in the structure below all the way down. Hell, for all I know all that is needed underneath is four sufficiently powerful charges placed on the four outer corner core columns on each floor and directed inward toward the core.

(V) That would be consistent with the collapses of 1 and 2 that we see on video. First the involved floors seem to disintegrate simultaneously and symmetrically. Then a downward sequenced pattern of powerful explosions eject from the corners of the structure below, which appear to unzip it at the corners.

(VI) That would also help explain why the collapse was not at free fall speed, but instead about 1.5 times slower than free fall. Less explosives should make gravity less efficient and make it appear that there was at least a little resistance. This allows the plotters to say that obviously at least a little momentum/ energy was conserved,(2) and leeway to raise issues before the math and science addled public over the right way to do the calculations.

(VII) If legitimate CDs rely more on gravity and less on explosives than we thought, and these nefarious CDs did the same, then the case for WTC CDs is actually easier to argue. The closer the WTC CDs are to conventional methods, the more they should look like CDs people are familiar with, so as expected, they see CDs when they watch them.

(VIII) The real ace is that SanderO's theory makes it easier to overcome the usual objection that it would be impossible to clandestinely rig tens of thousands of charges in a short amount of time. The greater the reliance on gravity, and the fewer the charges, the easier this is. It is even easier because unlike a legitimate CD, safety is not a concern; actually, the plotters want to kill people.

(IX) SanderO is right that a CD is still a CD regardless of the gravity/explosive ratio; what makes a CD a CD is whatever ratio needed to do the trick. The numbers don't matter. Indeed the hard point is whether there there was one or more explosive charge in a building, because even one has no business being there and would not be there if the OCT is true.

_____________________________________________
(1) I don't have a scientific definition for these percentages of "work", such as a unit (joules, newtons), formulas, or data concerning gravity or explosives. I don't think that is necessary for this simple gravity/explosives ratio. "Work" just means whatever total force was needed to collapse the three WTCs in the time and manner that was observed.

(2) With a 10 second free fall time, the 15 second actual collapse time, if assumed to be 100% gravity driven without use of any explosives, fails to satisfy The Law Of Conservation of Momentum.There's a video out there where a college physics student demonstrates that the minimum time needed to satisfy this Law was 42 seconds, but that is with the unsound assumption that there was no safety margin in the design. With the usual safety margins, more than 70 seconds is required. This kid shows his sources for formulae and data, explains his assumptions and conventions, and shows all his work, It takes 27 minutes to finish the computation. NIST is full of beans. It makes the one sentence bald claim that its gravity driven collapse satisfies this Law, without any support or explanation..
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SanderO
post Dec 29 2010, 08:34 AM
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Thanks tnemelckram

I've had a hard time making the points you so eloquently presented.

I am interested in the calculation of collapse time because I don't believe it would take that long. If we examine other CDs which typically take out only the lower section and then gravity comes in and the building crushes itself into the ground these can't proceed at free fall acceleration unless all the structure is taken out in the entire height and it rarely is I believe. A few stories are made "invisible" and the drop is at free fall for that distance and then it slows as the ground destroys the falling building.

It makes no sense to rig the entire height of the building if gravity will do MOST of the job and of course it will.

In WTC 7 we don't see 47 stories exploded to dust... we see the upper 30+ stories coming down.. with some free fall for 2.25 seconds and then at about 25+ mph which is the speed that a free falling object reaches after 2.25 seconds of acceleration.

Then it encounters resistance and the acceleration slows and the collapse takes an additional 5 seconds for the remaining 500 feet or so. This averages to 100 feet per second or 60+ mph. If we assume the speed of collapse was increasing but at a lower rate than free fall it had to go from 25+ mph to over 60+ in those 5 seconds. The acceleration was slowing but the speed was increasing.

A similar dynamic was present in the twin towers. The collapse of the very top was accelerating at FF for a second or two in the beginning. Then the acceleration slowed but the speed of collapse was increasing. The total collapse of the bottom was about 10 secs and this was about 1000 feet so the average speed was 60 mph. It may have take a few seconds to reach that speed and then it slowed down. We don't have (I think) accurate timing of the speed of progression for most of the collapse. We know it did not accelerate all the way down because after ten seconds I think an object in free fall is traveling over 110 mph. Please correct me if this is wrong. The problem is to cover the distance within the total time and this includes the ramp up in speed (acceleration). FF accelerates at 32 feet per second squared... but it could have accelerated slower and it could also reach a terminal velocity and make the goal post in the same time. Lot's of ways to skin this cat.

But the bottom line here is that gravity will provide the driving energy and the floors, contents and structure will provide the mass which is PE which overcomes the structure below. The conundrum is to calculate how much time it takes for the resistance... the strength of the structure to be overcome by the falling mass. In the case of the floor systems we know that their structural design was uniform for every floor. This makes sense because floors are designed for typical live loads and are of the same spans. What is changing is the mass which falls upon each floor. This is obviously increasing as the collapse proceeds down into the structure.

Failure proceeds through elastic deformation and then catastrophically - all at once - when the yield strength of the material is reached. We stretch the rubber band through its elastic limit and the instant we reach the yield strength it fails in an instant and parts. All materials have similar behavior, though few have as much ability to deform elastically. Building materials don't except some caulking seams which essentially fill gaps related to volume changes due to temperature.

In the case of materials which have little elastic ability (they don't stretch or compress or bend (ductile / malleable) they will fail "suddenly" when the elastic limit is reached. So in the case of the floor systems, once the conditions for overload PAST the elastic limit is met... a combination of static and dynamic loading.. the floor will fail catastrophically in an instant... like squeezing a wine glass. This process of loading the system though its elastic limit... takes time... even if it's a small fraction of a second. This is why the floors slowed the acceleration... they did provide resistance and overcoming it took a tiny bit of time. Physicists can perhaps do this calculation. It's complex because the floor system was a composite and different parts of it have different performance characteristics. Steel will bend and deform before it parts. Concrete will not.. it shatters more like glass.

I believe that in the case of WTC 1 the descending 17 floors was past the threshold elastic limit of the floor system so this collapsed the floor it came upon and then everyone below. The collapse did not come to a halt and begin again at each floor, but it was like a wrecking ball dropped which went right through all the floors it fell upon.

If you have the link to the calculation for time of collapse I would like to have a look at this. Since wtc 7 dropped at that speed... after the end of its free fall acceleration... the twins collapse should have seen similar terminal speeds of decent... and the did I believe.

This post has been edited by SanderO: Dec 29 2010, 11:47 AM
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tnemelckram
post Dec 29 2010, 09:49 AM
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Hi SanderO!

Heres a link to the physics student video. 3 parts total 27 minutes


http://www.youtube.com/watch?v=5QMSAsOkumI
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