NIST Officially Admits Freefall Speed re:WTC 7!!

Originally posted by pteridine
The acceleration was equal to gravity as best as can be measured, hence "small" and not "zero."

Yet, Page 45 of the NIST report states that the acceleration was equal to gravity.

The building did not oppose the collapse for 2.25 seconds because it didn't.

Huh? Would you like the chance to retype that sentence so it makes sense?

NIST didn't bother to answer because there was nothing to answer.

I would guess that NIST don't know how to explain why the building fell for 2.25 seconds without any resistance. Considering that this fact wasn't included in their draft report, I would also guess that they were hoping it would be overlooked until it was pointed out to them by a High School Physics teacher.

You still haven't answered how the building collapsed at a freefall rate without providing any internal resistance for 2.25 seconds. You're still avoiding the question, pteridine.

That column 79 must have had magical physical properties to drag down all of the other columns, without resistance, at the same time.

NIST said 94% of freefall,

Not full freefall, In fact that is in the video at the begining of this thread

reply to post by Achorwrath


I hate to pop your fantasy world, and reel you in to reality, however,this statement I will provide you with, is a FACT!

Challenges
In this critique I challenge NIST's explanation on two levels:
• Its theory about the effects of crash and fire damage is deeply flawed.
• Its presumption that "collapse initiation" will automatically lead to "global collapse" is unfounded.
Whereas the Report attempts to pre-empt challenges of the first type with the voluminous detail of its observations and models, it does not even address challenges of the second type. Yet it must have been aware of such challenges. NIST's lead investigator Shyam Sunder is extensively quoted in the Popular Mechanics article attacking "conspiracy theories." Respected theologian David Ray Griffin detailed evidence of controlled demolition in an April 18, 2005 address to the University of Wisconsin at Madison, which was aired twice on C-SPAN2's BookTV. Griffin's remarks included:
• The buildings collapsed straight down, and at virtually free-fall speed, as in controlled demolitions, and then the rubble smoldered for months.
• Many people in the buildings said that they heard or felt explosions.
• Virtually all the concrete of these enormous structures was pulverized into very fine dust.
• Much of this dust, along with pieces of steel and aluminum, was blown out horizontally several hundred feet.
• Most of the steel beams and columns came down in sections about 30 feet long, conveniently ready to be loaded on trucks.
By truncating its investigation at "collapse initiation" NIST avoids having to consider and disclose the subsequent evidence of controlled demolition.

911research.wtc7.net...

I could not take someone elses opinion and try to use it as fact.

Right! And you want everyone on ATS to take your word as if you are the foremost authority on 911.

Note how the central core of columns is not encased in concrete; notice how some of the outer columns have nothing more than a gypsum box around the H beams...

here
Really, please show me, and everyone else, where it states in this blue prints of WTC that the central core columns, are not incased in any concrete?

reply to post by Achorwrath

does not look like a massive pieces of concrete and steel to me.

You see what you want to see! LOL As you told me in another thread a few days ago. LOL

They are doing exactly what I said - they are forgetting that on 9/11 after the planes hit

The towers were no longer as designed

they were damaged. you can throw all thoughts of original design out the window

That is just your opinion, and it is not a fact.

They were experiencing something even the designers admit they never counted on.

That is BS, and you know it!

Like All Skyscrapers, the Twin Towers Were Over-Engineered
One aspect of engineering that is not widely understood is that structures are over-engineered as a matter of standard practice. Steel structures like bridges and buildings are typically designed to withstand five times anticipated static loads and 3 times anticipated dynamic loads. The anticipated loads are the largest ones expected during the life of the structure, like the worst hurricane or earthquake occurring while the floors are packed with standing-room-only crowds.

There is evidence that the Twin Towers were designed with an even greater measure of reserve strength than typical large buildings. According to the 1964 white paper cited above, a Tower would still be able to withstand a 100-mile-per-hour wind after all the perimeter columns on one face and some of the columns on each adjacent face had been cut. 7 Also, John Skilling is cited by the Engineering News Record

Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.
The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

911research.wtc7.net...

You do not read what is being sent to you, infact, this is the second time I have sent this to you, and you do not comment on any of it. You do what I see deniers do all the time when the facts hit them in the face, they just hand wave all the evidences, nothing new here.

I have read those before, they are others opinions not fact.

When you have some real facts and not the opinions from other threads on other sites bring them.

So you are telling me the WTC towers were designed to be on fire and have a plane fly through them? I wonder if that was in the lease terms.



The desgners admit to planning for a 707 flying at abouit 300MPH to hit the towers after becomming lost on landing

Not a 767-200 flying at 500+ carrying a full load of fuel

Originally posted by Achorwrath
NIST said 94% of freefall,
Not full freefall, In fact that is in the video at the begining of this thread

Try reading Page 45 of the NIST Final Report on WTC 7 and then report back to me.

reply to post by WonderwomanUSA


Some of the materials you referenced seem to be self inconsistent, or not factual, namely:

• The buildings collapsed straight down, and at virtually free-fall speed, as in controlled demolitions, and then the rubble smoldered for months.

The fact is that the fall was slower than freefall speed.

• Many people in the buildings said that they heard or felt explosions.

The fact is that they heard or felt what they thought were explosions.

• Virtually all the concrete of these enormous structures was pulverized into very fine dust.

Not true.

• Much of this dust, along with pieces of steel and aluminum, was blown out horizontally several hundred feet.

Hardly a sign of "controlled" collapse. Above they were said to collapse "straight down." The words "blown out" imply explosives, for which there is no evidence.

• Most of the steel beams and columns came down in sections about 30 feet long, conveniently ready to be loaded on trucks.

Thirty foot long pieces is how they were conveniently brought to the site to be assembled during construction. It is not surprising that 30' pieces are the result of collapse.

THere is more, but you get the gist of it from these examples.

I just wanted to quote what is in the Nist report again to be sure we're all talking about the same thing:

The slope of the velocity curve is approximately constant between about 1.75 s and 4.0 s, and a good straight line fit to the points in the range (open-circles in Figure 3-15) allowed estimation of a constant downward acceleration during this time interval. This acceleration was 32.3 ft/s2 (9.81 m/s2), equivalent to the acceleration of gravity g.

And then this:

In Stage 1, the descent was slow and the acceleration was less than that of gravity. This stage corresponds to the initial buckling of the exterior columns in the lower stories of the north face. By 1.75 s, the north face had descended approximately 2.2 m (7ft).

In Stage 2, the north face descended at gravitational acceleration, as the buckled columns provided negligible support to the upper portion of the north face. This free fall drop continued for approximately 8 stories or 32.0m (105 ft), the distance traveled between time t=1.75 s and t=4.0 s.

In Stage 3, the acceleration decreased somewhat as the upper portion of the north face encountered resistance from the collapsed structure and the debris pile below. Between 4.0s and 5.4 s, the north face corner fell an additional 39.6 m (130 ft).

It seems this thread is about Stage 2. I would think that if NIST were claiming even the slightest resistance in Stage 2 they would not have used the terms "at gravitational acceleration" or "this free fall drop" but would rather have used "near gravitational acceleration" and "this near free fall drop" respectively.

[edit on 21-3-2009 by NIcon]

reply to post by pteridine

• The buildings collapsed straight down, and at virtually free-fall speed, as in controlled demolitions, and then the rubble smoldered for months.

The fact is that the fall was slower than freefall speed.

Wrong! Try again, FACT, all three of the WTC fell in a few sec, “NOT” a few min.
Do you have something to back up your statement beside your opinions.

Tower Destruction Timelines
The Explosive Destruction of the Twin Towers, Second-by-Second
Each of the Twin Towers was totally destroyed in a matter of seconds. The score of videos archived here is the basis for a second-by-second timeline of the event.
The NIST Report does not give a duration for the events, nor does any other official report except for the 9/11 Commission Report , which states that the South Tower "collapsed in ten seconds." The duration of the destruction of each Tower remains a topic of confusion, based in part on misinterpretations of seismic data. The timelines listed here provide a reasonably accurate account of the progress of each Tower's destruction, and clearly show that each event lasted at least 15 seconds.

911research.wtc7.net...

Many people in the buildings said that they heard or felt explosions.
The fact is that they heard or felt what they thought were explosions.

You where not in the WTC, when they where exploding, these people where. Who are you, to assume what these people were seeing, and feeling. To bad for you, if you do not like what they had experience, like I said YOU were not there so you do not know what they went through. So, your statement is only your opinion, nothing more.

reply to post by pteridine

Virtually all the concrete of these enormous structures was pulverized into very fine dust.

Not true.

Wrong again, try and do some research before you give your opinions.

Concrete Pulverization
Twin Towers' Concrete Turned to Dust in Mid-Air
A striking feature of the Twin Towers' destruction was the pulverization of most of the concrete into gravel and dust before it hit the ground. This is evident from the explosive mushrooming of the towers into vast clouds of concrete as they fell, and from the fact that virtually no large pieces of concrete were found at Ground Zero, only twisted pieces of steel. 1 Estimates put the size of the particles, which also included gypsum and hydrocarbons, in the ten- to 100-micron range. 2
In trying to come to terms with what actually happened during the collapse of the World Trade Towers, the biggest and most obvious problem that I see is the source of the enormous amount of very fine dust that was generated during the collapses. Even early on, when the tops of the buildings have barely started to move, we see this characteristic fine dust (mixed with larger chunks of debris) being shot out very energetically from the building. During the first few seconds of a gravitational fall nothing is moving very fast, and yet from the outset what appears to be powdered concrete can be seem blowing out to the sides, growing to an immense dust cloud as the collapse progresses.
Even beyond the question of the energy needed, what possible mechanism exists for pulverizing these vast sheets of concrete? Remember that dust begins to appear in quantity in the very earliest stages of the collapses, when nothing is moving fast relative to anything else in the structure. How then is reinforced concrete turned into dust and ejected laterally from the building at high speed?

911research.wtc7.net...

reply to post by pteridine

Much of this dust, along with pieces of steel and aluminum, was blown out horizontally several hundred feet.

Hardly a sign of "controlled" collapse. Above they were said to collapse "straight down." The words "blown out" imply explosives, for which there is no evidence.

Boy you don’t stop do you, why don’t you try and do some real research and stop giving your opinions and hoping we will except it as fact.

Explosions
Explosive Events in the Twin Towers
While the explosive nature of the events that destroyed the Twin Towers is evident in their gross features such as the mushrooming of the tops and the huge clouds of concrete dust produced in the air, there are many specific observations that point to the detonations
Eyewitness Reports
Many eyewitnesses who were near the South Tower when it began its precipitous collapse reported sights and sounds of explosions. Several accounts are described in the evidence section.
Energetic Ejections of Dust and Objects
Explosive ejection of dust early in the collapse of the South Tower is clearly visible in the NBC video taken from far to the east, and in still frames from that video, portions of five of which are shown on the right. In addition to the large ejections of white dust from the left wall, the video shows a small high-speed ejection toward the back of the right wall, visible as a small white fleck in the first frame to the right.
Many of the photographs of the tower collapses show solid objects, such as sections of steel columns and aluminum cladding of the outer walls, being thrown ahead of the expanding dust cloud. This pattern is characteristic of explosive demolitions. According to Chapter 1 of FEMA's own report pieces of the steel columns and plates of the perimeter walls were thrown over 500 feet from the towers. The distribution pattern they diagram suggests that, with both towers, perimeter wall pieces were thrown an average of about 150 to 200 feet outward. This is corroborated by the shape of the vertical holes in WTC 6.
South Tower Demolition Wave
A three-second movie shows about 2.5 seconds of the South Tower collapse starting at about three seconds into the plunge of the tower's top. The short movie shows the roughly spherical debris cloud nearly double in size, even accounting for the perspective. The leading edge of the wave is about to reach the 44th-floor sky lobby when the camera operator turns to run. The movie (mpeg) was found on plaguepuppy's cafe with the following description.

911research.wtc7.net...

reply to post by pteridine

Most of the steel beams and columns came down in sections about 30 feet long, conveniently ready to be loaded on trucks.

Thirty foot long pieces is how they were conveniently brought to the site to be assembled during construction. It is not surprising that 30' pieces are the result of collapse.

Really! Please show some proof to support your statements

THere is more, but you get the gist of it from these examples.

What examples? I only see you rambling about your opinions, you have not presented one single fact to support your opinions. You have not given us any links, or sources, just your opinions, nothing more.

reply to post by WonderwomanUSA


Ah, Wonder, if you don't believe that they fell slower than free fall look at the videos. You will see pieces from the top of the buildings beat the collapse to the ground. Those pieces are falling at freefall speeds in air. That means slower than free fall for the collapse. Seismic data also says slower. Pieces of the core stand for 15 seconds or so after the outer structure has collapsed, so that is slower yet. You seem to think that this should have been a much more leisurely collapse. A semi-catastrophe of sorts.
Try not to capitalize "fact." It is properly spelled "Error," anyway.

reply to post by WonderwomanUSA


Wonder,
Read carefully the part about "appears to be." Note that large amounts of gypsum were found. Gypsum is plaster. It is easily broken and produces fine dust. There is lots of it in the building. See the "appears to be" in your quote?
The dust was a mix of concrete and gypsum, for the most part. You are believing that website again when they hint at explosives making concrete dust. They really don't understand explosives because if there would have been enough explosive to pulverize all the concrete to dust, even they would have noticed the bang.

Originally posted by pteridine
Ah, Wonder, if you don't believe that they fell slower than free fall look at the videos. You will see pieces from the top of the buildings beat the collapse to the ground. Those pieces are falling at freefall speeds in air.

You really need a few lessons in basic physics, pteridine.

The term freefall refers to acceleration, not speed.

Lots of loose debris, seen in lots of videos, fall to the ground with freefall acceleration. However, they did not all have the same initial speed. Some pieces may have fallen faster than others, due to differing initial speeds. All pieces of debris falling to the ground are acted upon by the same gravitational acceleration.

Now, with your apparent ignorance for basic physics, will you please explain why WTC 7 fell at a freefall rate for 2.25 seconds in the early collapse sequence?

reply to post by WonderwomanUSA


These were the walls collapsing outward as the floor joists failed. It has to do with the structure of the building and how the outside was pinned to the core. When the floors failed, the outer columns were unsupported and fell outward.

reply to post by Achorwrath

When you have some real facts and not the opinions from other threads on other sites bring them.

Why bother, you will just hand wave them anyway, especially if it doesn’t fit your conspiracy theories.

So you are telling me the WTC towers were designed to be on fire and have a plane fly through them? I wonder if that was in the lease terms.

Yes the WTC where designed to handle fires, and being hit by several jumbo commercial airliners, I sent you the links, and sources, that confirms my statements with facts. But you just keep hand waving.

The desgners admit to planning for a 707 flying at abouit 300MPH to hit the towers after becomming lost on landing

Not a 767-200 flying at 500+ carrying a full load of fuel

LOL it makes no different the Boeing 767 is just a little bigger than the Boeing 707 but not very much different. As fare as speed it makes no different if the planes where doing 300 knts or 500 knts. The WTC where designed to withstand a direct hit by several airliners without knocking the building down and that is a FACT.

Not a 767-200 flying at 500+ carrying a full load of fuel

LOL There you go again, just given us your opinions, nothing more.

reply to post by tezzajw


So what pieces falling to the ground started with -V at t zero, Tezza. Are you claiming that an exterior force was acting in the down direction? This is better than CIT's theories.

As to the magical 2.25 seconds of freefall, that must be a result of a catastrophic collapse brought on by failure due to fire. What do you think it was?

reply to post by pteridine

These were the walls collapsing outward as the floor joists failed. It has to do with the structure of the building and how the outside was pinned to the core. When the floors failed, the outer columns were unsupported and fell outward.

You are posting nonsense, start posting some sources, and links, to validate your findings I don’t care about your opinions, as you don’t care to hear mine.
Until then, do not waste your time with me, posting ridiculous opinions.

Originally posted by pteridine
So what pieces falling to the ground started with -V at t zero, Tezza. Are you claiming that an exterior force was acting in the down direction? This is better than CIT's theories.

Wow, you claim to have watched the videos and you can't see ANY forces acting on loose debris? Amazing... try watching them again.

Every time a piece of metal snaps, there's a supplied force acting on objects around it. Those large column sections break away from their bolts, snapping lots of other bits and pieces - there's forces acting... think about it before you respond, pteridine and watch the building collapse again, destroying itself and giving lots of loose debris different forces to cause different initial ejection velocities.

If you know anything about velocity, you'll know that it's a vector quantity. So, some forces must have acted on the loose debris to propel them in an arc away from the building. The only way debris can arc from a building is if there is a sideways component to velocity, to resolve with the downward component, in 3-D space, of course.

No forces in the building collapse would have meant that everything dropped STRAIGHT down. Now that didn't happen, did it? Maybe you have a different video that shows otherwise?

As to the magical 2.25 seconds of freefall, that must be a result of a catastrophic collapse brought on by failure due to fire. What do you think it was?

Explain the mechanism of the catastrophic failure? Providing a guess without any proof is pointless. Column 79 must have been sprinkled with magic fairy dust to completely negate the internal resistance of WTC 7 for 2.25 seconds.

I don't know what can cause a building to experience no resistance for 2.25 seconds early in its collapse sequence. That's why I'm asking you. You think that it's all good and above board, so you should have the answers. NIST don't provide the answers, they only confirm the observation that WTC 7 fell for 2.25 seconds with a freefall rate.