WTC7: Does This "Look Like" a Controlled Implosion?

[Joe Hill]

From another thread:

Source: http://www.youtube.com/watch?v=ixwx19t2IMQ


It certainly looks like a planned building implosion, doesn't it?

Nothing else can make a building fall straight down all at once like that.

Source: https://www.youtube.com/watch?v=A49a9pXwDQs


I ask you to just look at the 2 short videos I gave you with an open mind.

Thank you

Chris

Full post: https://www.metabunk.org/threads/nist-motive-speculation.11094/post-236350

A closer inspection reveals the first move of the visible perimeter frame was a sudden lurch to the left at the moment the west penthouse descended. There is no descent of the perimeter frame. The east half of the structure is falling over to the north at onset of the perimeter frame.
An explanation of that motion: https://www.metabunk.org/threads/debunked-the-north-face-of-building-7-was-pulled-inward.10796/


Watch the left vertical edge (NE corner). It is falling over toward the camera, pivoting far below what is visible, near the ground. Watch the left face; it is turning to face the camera.
Does this look like controlled demolition? How does controlled demolition make the structure move like this? There is no drop, sudden or otherwise; just half the structure falling over.

Your second video shows the east half continued falling north throughout descent, creating the "kink", or vertical fold of the north face.


The east half is fully facing the camera, falling north, while the west half is noticeably falling south.


The west half has still not distorted commensurate with the radical motion of the east half. The two "halves" are falling over in opposing directions.
How did controlled demolition cause the perimeter frame to behave as two separate units during collapse, connected by the north wall?
No, it doesn't "look like" controlled demolition to me. It behaves like a perimeter frame that sustained a vertical breach somewhere out of view of the camera.

 

[Christopher 7]

From another thread:

Full post: https://www.metabunk.org/threads/nist-motive-speculation.11094/post-236350

A closer inspection reveals the first move of the visible perimeter frame was a sudden lurch to the left at the moment the west penthouse descended. There is no descent of the perimeter frame. The east half of the structure is falling over to the north at onset of the perimeter frame.
An explanation of that motion: https://www.metabunk.org/threads/debunked-the-north-face-of-building-7-was-pulled-inward.10796/


Watch the left vertical edge (NE corner). It is falling over toward the camera, pivoting far below what is visible, near the ground. Watch the left face; it is turning to face the camera.
Does this look like controlled demolition? How does controlled demolition make the structure move like this? There is no drop, sudden or otherwise; just half the structure falling over.

Your second video shows the east half continued falling north throughout descent, creating the "kink", or vertical fold of the north face.


The east half is fully facing the camera, falling north, while the west half is noticeably falling south.


The west half has still not distorted commensurate with the radical motion of the east half. The two "halves" are falling over in opposing directions.
How did controlled demolition cause the perimeter frame to behave as two separate units during collapse, connected by the north wall?
No, it doesn't "look like" controlled demolition to me. It behaves like a perimeter frame that sustained a vertical breach somewhere out of view of the camera.

Even with those nuances, it's obviously a controlled demolition. The moment frames (3' high I beams bolted through the columns on every floor) held the exterior columns together as the building fell. Although the building twisted some, the frame held together as the building descended.

The straight down fall of the entire building is only possible in a controlled demolition. Fire just can't do that.

The 100 feet of free fall acceleration is proof beyond a shadow of doubt that WT 7 was a controlled demolition. People have tried to double talk around this but the laws of physics are absolute. Bending steel provides resistance. Free fall means NO resistance.

Sunder even admits that "A free fall time would be an object that has NO structural components below it." and then says "there was structural resistance that was provided in this particular case."

[video removed Link Policy]

 

[Jeffrey Orling]

Fire didn't do that... structural failures did. Gravity made it collapse down... which is because that is how things fall - down,

The structure supporting the NE section led the collapse sequence and it is seen as the first movement of the collapse. The structure has multiple transfer structures which explains how the structural failures propagated rapidly from the NE section through the building.

Much like the twin towers... with their column free office space and a structural "facade".. the interior collapsed lead the perimeter collapse.

The form and sequence of the collapse was an artifact of the structural design. The structural failure propagation can also be explained by the inability of the compromised structure - loss of axial lines of support, to be redistributed successfully. The redistribution essentially overwhelmed to axial lines that received new loads. Failing axial lines pulled surrounding axial lines laterally, destroying connection to floor girders.

A "natural" collapse cause ie structural failure originating at even a single location (another discussion) could conceivably be achieved with sufficiently powerful explosive etc. to destroy the column line. There seems to be no evidence that an explosion of sufficient force took place. No explosion sounds were heard and no steel showed the tell tale sign of being exploded.

The building did not entirely fall into its footprint as claimed. Much of it feel to the north because of moments developed related to the sequence of the structural failures.

Humpty Dumpty sat on a wall,
Humpty Dumpty had a great fall.
All the king’s horses and all the king’s men
Couldn’t put Humpty together again.​

And there was no evidence that it was a CD.

 

[cloudspotter]

Fire didn't do that... structural failures did. Gravity made it collapse down... which is because that is how things fall - down,

This is the way I look at it too. All demolition charges do is it to remove a structure's resistance to gravity

 

[Jeffrey Orling]

Everything falls at free fall.
The facade fractured at the 7th floor... where the transfers were. This was 100+ feet above the ground. That's your 2+ seconds of FF.
Notice how the structure below flr 7 is radically different from above floor 7... 57 columns resolved into 26. More than half the facade columns above 7 did not go straight down to the foundations.

 

[Mick West]

The 100 feet of free fall acceleration is proof beyond a shadow of doubt that WT 7 was a controlled demolition. People have tried to double talk around this but the laws of physics are absolute. Bending steel provides resistance. Free fall means NO resistance.

The point has been made that if the bending steel was only offering a few tons of resistance, rather than the few hundred tons it normally supports, then that's just 1%, despite being tons of resistance.

99% of gravity is indistinguishable from gravity alone at the resolutions available. So it's quite possible that the columns vanishing would look like the columns buckling.

This point perhaps deserves a more focussed thread.

 

[Joe Hill]

The structure supporting the NE section led the collapse sequence and it is seen as the first movement of the collapse.

The visual record shows what led collapse sequence (of the perimeter frame) was the east half falling over, which then led to failure of lower support.
We can see only the north and west faces. The perimeter of the structure is connected as one unit, so we know if the NE wall is falling north, the east wall, and some part of the south wall are falling over with it. It wasn't just the NE support involved.
"Supporting structure" of the east perimeter frame was perimeter columns. Failure of those columns could not have caused the entire east half to lurch north as it did without a very noticeable drop. There was no drop of the NE corner at onset. The east half lurched north immediately when the west penthouse initiated descent. The only possible way I can figure is the east half was leaning north, which would be what led collapse sequence of the perimeter frame, lower column support thus reacting to the sudden dynamic load.

 

[Joe Hill]

Even with those nuances,

Explain how half the structure falling over at onset is a "nuance".
If you are going to claim controlled demolition brought down the visible perimeter frame, it's initiating motion was thus caused by controlled demolition. A clear explanation of how controlled demolition can make half the structure fall over, with no drop, sudden or otherwise, is warranted.
Let's start there. We'll address the alleged free fall portion of collapse, which occurred some 2.5 seconds later, in sequence.

 

[Christopher 7]

The point has been made that if the bending steel was only offering a few tons of resistance, rather than the few hundred tons it normally supports, then that's just 1%, despite being tons of resistance.

Please site your source for that 1% .

 

[Jeffrey Orling]

Explain how half the structure falling over at onset is a "nuance".
If you are going to claim controlled demolition brought down the visible perimeter frame, it's initiating motion was thus caused by controlled demolition. A clear explanation of how controlled demolition can make half the structure fall over, with no drop, sudden or otherwise, is warranted.
Let's start there. We'll address the alleged free fall portion of collapse, which occurred some 2.5 seconds later, in sequence.

I don't see half, or even the portion east of the core falling separately from the rest of the building.
No one can see inside.... but
The EPH drop looks like it may have dropped completely thru the tower.... and if the rest of the interior dropped it would have done so after that East portion.
When I see the perimeter/facade/moment frame coming down, there is a distinct "kink" or fold near column 48 (moment frame). What appears to be happening is the building East of the kink is rotating toward the camera location and the West side is not.... or much less so.

It also appears that some of the East facade fell on top of the interior based on the debris pics as well at across the street to the north.

To account for the rotation/moment... the structure low down in the Northeast had to have failed and descended before the structure to the West... essentially pulling the mass north east.

 

[Christopher 7]

Explain how half the structure falling over at onset is a "nuance".
If you are going to claim controlled demolition brought down the visible perimeter frame, it's initiating motion was thus caused by controlled demolition. A clear explanation of how controlled demolition can make half the structure fall over, with no drop, sudden or otherwise, is warranted.
Let's start there. We'll address the alleged free fall portion of collapse, which occurred some 2.5 seconds later, in sequence.

Half of the structure could not act independently because of the moment frames which held the building together. Here is NIST's model buckling and folding but not coming apart and not falling at free fall acceleration after about 34 feet of fall. (bold type added)

The free fall acceleration drop of about 100 feet was first found by a math and physics school teacher and later confirmed by NIST. They each use different software and a different spot on the roofline but still got the same results. That is scientific conformation. Especially when coming from both sides in the WTC 7 collapse controversy.

 

[Jeffrey Orling]

The moment frame block in a long vertical crease... Anyone can see that.
The free fall period of decent is of the perimeter.... that's the only thing that can be seen and can be therefore confirmed. The collapse of the EPH, screen wall and WPH before facade descent is a tell that the INTERIOR had already/just recently collapsed. If this assumption is correct.... that collapse completely wiped out the interior structure and with that the axial support of the moment frame above floor 7 where there was a belt truss around the entire building.

I would suggest that the total interior collapse of the NW quadrant interior... kicked off a rapid progression of the interior structure from east to west... the sequence of the decent of the roof structures.

Decent from the belt truss down at FF would take the 2+ seconds. Note that the moment frame had 57 column and the axial support for the 2 / 3 story belt truss had only 26 columns supporting it.

 

[Todd Cee]

I am still astonished NIST, Hulsey nor anyone else has addressed the fact that WTC 7 must have had a compromised foundation considering the fact that 2 massive hi rises right next door slammed into the ground with incredible energy ... my physics background would say that the majority of said energy went lateral ... I'm a retired field mechanical engineer so not sure of my theory so please feel free to dissect ....

 

[Jeffrey Orling]

I am still astonished NIST, Hulsey nor anyone else has addressed the fact that WTC 7 must have had a compromised foundation considering the fact that 2 massive hi rises right next door slammed into the ground with incredible energy ... my physics background would say that the majority of said energy went lateral ... I'm a retired field mechanical engineer so not sure of my theory so please feel free to dissect ....

Explain.... yeah the ground trembled...

 

[Joe Hill]

Half of the structure could not act independently because of the moment frames which held the building together. Here is NIST's model buckling and folding but not coming apart and not falling at free fall acceleration after about 34 feet of fall.

Do the NIST models of perimeter frame motion look anything like what we can see? Obviously not. NIST understood the north face sustained a vertical fold, but went no further in understanding/explaining it, other than trying to show "localized distortions", which we know are not possible, due to your accurate assertion the frame was too stiff. Hulsey also tried to duplicate the visible distortion of the perimeter frame, but was unable to do so, according to Mick West. Hulsey's models showed no distortion of the perimeter frame, at onset or after.
The fact the entire NE corner is moving to the left in the initiation gif shows this was not a localized distortion, but the entire east half falling over to the north.
I would suggest further study of https://www.metabunk.org/threads/debunked-the-north-face-of-building-7-was-pulled-inward.10796/

The moment frames (3' high I beams bolted through the columns on every floor) held the exterior columns together as the building fell.

I agree the perimeter frame was rigid, and should have held together for at least part of it's descent. (I can find no evidence that spandrel beams were bolted to perimeter columns however; only that they were sandwiched between columns and welded.)

Although the building twisted some,

The perimeter frame did not "twist" as it fell. The plane of the west side never lost it's original orientation, or turn counter clockwise commensurate with it's east wall counterpart, which was falling counter clockwise, to the north. The perimeter frame fell over in two opposing directions as it descended, giving it the appearance of twisting.
This is why when you state, "It looks like...", it's important to understand what you are looking at. Here's some help:

...the frame held together as the building descended.

Based upon the motions we can see (this thread is about what it "looks like"), it is impossible for the perimeter frame to have remained intact around it's circumference. Geometry of a trapezoidal solid, and how it would have to alter form in order to accommodate what we can see, tells us the perimeter frame did not behave as a complete trapezoidal solid.
I roughed out the geometry for you. First, I traced the roof lines at about 7 floors of descent from your video. The north face vertical fold angle is actually deeper than what it appears due to camera angle, but I'll go with what shows on video, about 20 degrees:


Next, I transposed the shape of the roof line at this stage of collapse, about 7 floors of descent, and what form it would take were it an unbroken trapezoid shape. The shape would have to flatten, which would push the SW corner outward. No such movement can be seen in the SW corner at any point during collapse:

(Red line = perimeter wall shape during collapse)

Distortion of the trapezoid occurred immediately at onset of the perimeter frame structure. At the moment the west penthouse descended, the NE corner lurched to the north. A diagram of that motion shows the SW opposing corner should have pushed out to the west just as quickly; immediately. The SW corner never distorted:


Two video frames show the NE corner lurched north at onset, prior to descent:


Based on the motions we can see, the perimeter frame was not a complete trapezoid shape at onset of it's collapse.

The straight down fall of the entire building is only possible in a controlled demolition.

As shown, "straight down" does not describe what we can see. It's first move was over, and it continued over as it descended, falling over in two opposing directions as it descended.

The 100 feet of free fall acceleration is proof beyond a shadow of doubt that WT 7 was a controlled demolition.

False. The alleged free fall portion of descent is proof there was little to no resistance during that portion of descent, period. Anything more is conjecture. Columns that buckle and break apart at connections will be misaligned at the point of break, leaving nothing between the upper part of the columns and the ground to resist their fall.
Typical of all proponents of controlled demolition that I've encountered (hundreds), you want to focus on something that occurred partway through collapse of the perimeter frame, but ignore, or try to minimize the approximately 2.5 seconds of it's collapse prior. If you wish to continue ignoring the fact the first move of the perimeter frame was over, with no drop, and fail to explain how controlled demolition can create that movement, then you must believe they waited to set off the charges until the structure started falling on it's own.
As you surely know, THE consistent feature of controlled demolition of buildings is a sudden drop of some part of the roof line at onset. The perimeter frame collapse of Building 7 displayed no such feature. It's first move was over; no drop. How did controlled demolition cause that?

 

[Jeffrey Orling]

or this

 

[Joe Hill]

or this

Your diagram does not comport with what we can see. The west wall did not fold inward as you show.

 

[Jeffrey Orling]

You are not reading it correctly and it's not clear... the entire building rotated... the east side more than the west side... the kink was the "fault line".

 

[Joe Hill]

You are not reading it correctly and it's not clear... the entire building rotated... the east side more than the west side... the kink was the "fault line".

The plane of the west wall never altered it's orientation, as we discussed here. Sorry, but I'm reading it clear. You had to move the SW corner inward to the east in order for your geometry to fit. It didn't. It is also patently clear the SW corner did not move inward in the initiation gif above in my OP. Were the SW corner moving east in order to accommodate the NE corner move to the north, it would have done so at onset.

Note the angle shown in panel 1 does not change. Your diagram shows it narrowing:

 

[Christopher 7]

the frame held together as the building descended.

Based upon the motions we can see (this thread is about what it "looks like"), it is impossible for the perimeter frame to have remained intact around it's circumference

The video clearly shows that the external frame held together. It didn't remain a perfect trapezoid but there is no sign of it coming apart, your 'geometry" notwithstanding.

 

[Christopher 7]

Do the NIST models of perimeter frame motion look anything like what we can see? Obviously not.

I agree. The NIST model does not come close to replicating what we see in the videos.

Hulsey also tried to duplicate the visible distortion of the perimeter frame

No, Hulsey was trying to show what the building would do id column 79 were removed on different floors. The fact that the external frame does not buckle casts doubt on his simulations.

I agree the perimeter frame was rigid, and should have held together for at least part of it's descent. (I can find no evidence that spandrel beams were bolted to perimeter columns however; only that they were sandwiched between columns and welded.)

Above Floor 7, WTC 7 had an exterior moment frame. Column trees were fabricated for the east and west facades with bolted field splices at the spandrel beam midspans. On the north and south facades, the spandrel beams had moment resisting bolted flange and web connections. NCTSTAR 1-9, Vol. 1, p. 30 [PDF p. 74]

Content from External Source

 

[Cadmonkey]

I read this thread with some interest...but I think the answer to your question has already been provided to us by the Alaska Fairbanks University study of the WTC 7 collapse. The most accurate and indeed the only computer simulation of the whole collapse, which can be viewed towards the end of the video clip below:

Source: https://www.youtube.com/watch?v=Xd7tqpwdlpQ


I think you will agree the simulation is a good approximation of what we see in the video footage, unlike the NIST simulation, which looks absolutely nothing like it. In addition the report itemises the many errors, omissions and wrong assumptions, that were needed in order to get their fire induced collapse theory to work at all.

the Alaska Fairbanks simulation shows the simultaneous failure of all internal columns over 8 stories, followed by the simultaneous failure of all exterior columns over 8 stories, 1.3 seconds. It makes perfect sense than in the intervening period the outer wall is going to distort, moving laterally, outward or inward, without dropping as the outer columns have not yet failed. I know little of controlled demolition, but imagine this is done in order to encourage the outer walls to collapse inward.

True the Alaska Fairbanks report makes no mention of controlled demolition, however I know of no other means of bringing about the simultaneous failure of all interior columns, followed by the simultaneous failure of all exterior columns 1.3 seconds later...certainly no office fire can do that.

 

[Christopher 7]

Joe Hill,

It would be impossible for all the columns on any given floor to break and become misaligned at the same time which would be necessary for the building to fall straight down as it did for 100 feet. If columns break and become misaligned, they will fall one floor and then the floor above will come in contact with the floor below. That will create resistance which would preclude free fall.

NIST said that there were 1.75 seconds before onset of free fall.

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 (7 ft). NCSTAR 1A, p. 45 [PDF p. 87]

Content from External Source

Chandler used the NW corner of the roofline (parapet wall) and NIST used a spot above the east end of the louvers.

The chosen feature was the top of the parapet wall on the roofline aligned with the east edge of the louvers on the north face. NCSTAR 1-9, Vol. 2, p. 600 [PDF p. 262/666]

Content from External Source

The spot NIST used dropped about 7 feet before the onset of free fall and the NW corner descended about 2 feet before going into free fall. The east end was a few feet lower than the west end and the remained the same for the next 100 feet.







Here are Chandlers analysis and NIST analysis (flipped to be descending like Chandler’s)
Note the slight descent and then a pause in velocity increase before free fall in both graphs.



The video shows the screenwall and west penthouse falling into the building from east to west in about 1/2 second. At that point the entire building goes into free fall. That is what happens in a building implosion. The core columns are taken out a split second before the exterior columns so they pull the floors down which pulls the exterior columns inward. Then the exterior columns are taken out. (all at once on 8 stories in this case). There is no other way free fall can occur. Your denial of that notwithstanding.

 

[Jeffrey Orling]

Joe... We can't see the SW corner so one can only presume it remained in the same plane location as the tower collapse. I imagine that the the face "broke" in 3 locations... the visible kink, the NE corner and some place along the south facade. I have not determined the precise location of the north kink... but I am guessing it is likely no further west than col 48 nor further east then col 46... based on the structure. Someone can determine this. Note that the face was supported on the end of cantilevers from col 47 to col 54 (8 columns) almost 50% of the entire north facade. The failures of TT1 and TT2 likely caused the building to "break" on a N-S axis where the observed kink is.

It appears to me that perhaps the interior from the kink to the east came down first then the failures raced across the "purple" E-W transfer that supported the MG27 cantilevers. The TT3 failed and the west interior collapsed. The interior collapse led to the undermining of the facade support below the 2-3 story belt truss which topped off at floor 7.

When the EPH came down all the floor plates in the NE-E side fell as well leaving nothing to brace the face on the entire east which could explain why it "folded" and broke away.

We can't see the south side so we don't know if the facade remained intact and did not part mid way or at the SE corner as it fell. We can't even see the East facade because of the camera angle and the shape of the building. It was obscured by the north face..

 

[Todd Cee]

Explain.... yeah the ground trembled...

the ground trembled? ... of course it did ...

the seismic recordings were fairly significant and recorded 266 miles away from ground zero ... where did the energy from the collapses of 1 and 2 go? ... I'm just positing a theory that the foundation of 7 was compromised and possibly led the to collapse ...

 

[Jeffrey Orling]

the ground trembled? ... of course it did ...

the seismic recordings were fairly significant and recorded 266 miles away from ground zero ... where did the energy from the collapses of 1 and 2 go? ... I'm just positing a theory that the foundation of 7 was compromised and possibly led the to collapse ...

How so? Fires caused failure seems to make sense. Exactly where and how is the question.

 

[Joe Hill]

Joe... We can't see the SW corner so one can only presume it remained in the same plane location as the tower collapse.

Yes we can see the SW corner. It is clearly NOT moving to the east. From this view, it never moved to the east.


From the other view, the plane of the west wall never changed it's orientation to the camera. Had the SW corner moved to the east, wall depth would have shortened, and the NW corner to west roof angle would have become more acute.

The visual record is crystal clear Jeffrey. The SW corner was not pulled inward, as you assert in order for your theory to be correct, nor was it squeezed outward, as it should have as the trapezoid shape was flattened. I'm not going to discuss this point any further with you.

 

[Jeffrey Orling]

You didn't look at post #24 which says nothing about the SW corner moving east... at least during the period we can see in the video.

I am suggesting that PERHAPS the facade and moment frame around the EAST side of the building...broke free.., the kink we can see and the rest we have no idea. But without the floor to brace the moment frame and hold its plan shape it could have "broken" into sections.

We can't tell what happened and when it happened, But it looks like the action started on the east side and the west action came after... that is the interior. All of the facade/moment frame dropped when the entire support it had was lost

 

[Joe Hill]

the ground trembled? ... of course it did ...

How so? Fires caused failure seems to make sense. Exactly where and how is the question.

Let's stay on topic please. This thread is about what we can see.

You didn't look at post #24

Yes I did. Again, you played around with the angles to "make it fit", but ended up with the building falling along the plane of the east wall, which would be impossible without a drop of the NE corner. It didn't fall in that direction. It fell to the north, which would move the roofline of the east wall to the north as well.

I am suggesting that PERHAPS the facade and moment frame around the EAST side of the building...broke free..,

Once again, the visual evidence does not support that it broke free during collapse. By falling over in the direction it did, lateral dynamic load on the south wall would be east to west, pushing along the plane of the wall. The SW corner would have to push outward, even if the wall were buckling horizontally, instantaneously. But yes, the visual evidence tells us there was a vertical break in the unseen part of the perimeter frame at the moment of it's onset.

We can't tell what happened and when it happened,

Yes we can. If we understand the motions made by the structure we can see, we can understand the motions of what we can't see. Other evidence can then confirm or deny our understanding of the motions. This is why I consider it vital to understand the motions, which neither NIST nor Hulsey understood or conveyed.

 

[Joe Hill]

I think you will agree the simulation (by the Alaska Fairbanks University) is a good approximation of what we see in the video

I do not agree. The Hulsey simulation failed to incorporate the fact initiation of the perimeter frame was the east half falling over to the north prior to any descent, as did NIST.

It would be impossible for all the columns on any given floor to break and become misaligned at the same time

We are talking about perimeter columns, not "all" columns. We can see the penthouses going down first, meaning their supporting columns failed, and we can see perimeter walls draped on top the pile. We know the perimeter frame was largely disassociated with the perimeter structure during descent.

NIST said that there were 1.75 seconds before onset of free fall.

There were 1.75 seconds of descent. Prior to that was .75 seconds of the east half of the structure falling over, with no drop. I'll ask again, how did controlled demolition cause that motion?

 

[Christopher 7]

It would be impossible for all the columns on any given floor to break and become misaligned at the same time

We are talking about perimeter columns, not "all" columns.

OK, it would also be impossible for all the perimeter to fail at the same time.

We can see the penthouses going down first, meaning their supporting columns failed

Correct. Note that the screenwall and west penthouse start down, east to west, in about 1/2 second.
In the NIST collapse scenario, it takes 3 seconds. That is enough to invalidate the NIST hypothesis.

Figure 12–52. Failure of Columns 77 and 78 due to failure of Truss 2 from debris impact
[Time: 2.5 (18.5) s]. NCSTAR 1-9, Vol. 2, p. 582 [PDF p. 244/648]
Figure 12–53. Buckling of Column 76 from the load transfer and debris impact from the buckling of Columns 79 and 77 [Time: 3.5 (19.5) s]. NCSTAR 1-9, Vol. 2, p. 582 [PDF p. 244/648]
Figure 12–55. Buckling of all interior columns [Time: 6.5 (22.5) s]. NCSTAR 1-9, Vol. 2, p. 583 [PDF p. 245/649]

Content from External Source

NIST admits that their model does not look like the actual collapse.

The results of this scenario were consistent with observations except that the screening wall on the roof fell downward before the west penthouse. NCSTAR 1-9, Vol. 2, p. 612 [PDF p. 274/678]

Content from External Source

There were 1.75 seconds of descent. Prior to that was .75 seconds of the east half of the structure falling over, with no drop.

The NE corner appears to stretch, which of course, it cannot do. But we would see more of the north face if the east end rotated toward the camera. That is just a matter of perspective because the frame cannot stretch or break apart. (until the upper portion, falling at 55 mph after 100 feet of free fall, collided with the lower portion of the building)

It would be impossible for the exterior frame to break apart at the beginning of the collapse because it is held together with moment frames which are essentially a steel belt, welded to the columns, all the way around the building on every floor.

I'll ask again, how did controlled demolition cause that motion?

How did a gravity collapse cause that motion?
answer: It could happen in a demolition or gravity collapse.

 

[Jeffrey Orling]

Joe, I agree that the visuals.. movement of the building parts is a clue to what was happening. My thinking is as follows.

Axial support below the EPH had to be the first fail because EPH was the first observed movement. It descended and apparently down through the tower.

Similar would apply next to the Screen wall structure and finally the WPH. Both had to have lost axial support to permit them to fall down into and perhaps through the tower.

We need to look at the structure to inform our thinking.

1 - the design was a column free office space except on the East side where col 790. 80, 81 were (under the EPH. These columns did not extend DIRECTLY to the foundations

2 - notable structural design features were:

8 massive girders which extended from the core to support a large portion of the north moment frame on the end of cantilevers. The core side of these girders was a massive E-W girder at the north side of the core.

3 massive 2 story tall transfer trusses supported axial loads from above... two on the east side and one on the west side.. ALL THESE "TRANSFER" STRUCTURES WERE INTERCONNECTED... ie FRAMED INTO ONE ANOTHER.

There were 57 columns in the moment frame above floor 7 and only 26 below. 31 moment frame columns were supported on "trusses" or transfer girders (MG23s)

The girders/beams which supported the floor system were framed into girders or spandrel beams not to columns directly. VIRTUALLY ALL AXIAL LOADS WERE TRANSFERRED LATERALLY TO AND THEN TO THE FOUNDATION VIA AN AXIAL LOAD PATH.

++++

For the north face to have a multi story fold or kink would mean that there was a lateral force applied to one side (east of the fold) and not to the other.

In the collapse of the twin towers we witnessed the floor plates collapsing inside the perimeter and the perimeter becoming unstable and forced outward but the massive debris avalanching down inside the facade. We saw massive sections of the facade fall away many stories high and as wide as the tower itself in some cases. Take away was that the facade held together but was forced outward as there was no floor structure left to hold it in place vertically.

I suspect something similar occurred to the east side of 7 wtc. That is, the interior of the east side completely collapsed and it left the perimeter from the kink/fold eastward with no lateral bracing/support. Like the twin towers' facade they acted like stiff multi story plates.

We can't see where the plates "broke" except for the north face kink. And for the NE corner to move northward it had to either pull the East facade with it... or separate from it. WE CAN'T KNOW because WE CAN'T SEE.

So there are several possible likely "break" locations:

NE corner
SE corner
somewhere along east face
somewhere along south face

The floor mass distribution was largest on the east sector which included col 79. 80. 81 and TT1 and TT2 below them.

Each of the 5 regions collapsed... in a sequence from east to west... weakening and causing the facade to likely ultimately break in several places.. The structure was the form of collapse driver.

 

[Joe Hill]

Joe, I agree that the visuals.. movement of the building parts is a clue to what was happening. My thinking is as follows.

Precisely. It's why this thread is based on what we can see. Did it "look like" controlled demolition?
This thread is to explore that question, not what we think did happen.
Can controlled demolition make the perimeter structure move in the manner we see?
What structural parts would have to be severed in order to create the movement we see?
Any theory will have to meet three standards:
1. Comport with what we can see.
2. Comport with known structural evidence and debris patterns.
3. Comport with structural design of the building.
Any theory offered has to meet those criteria. If not, it's invalid.

First, we have to understand what we see. There is a sufficient body of structural evidence and structural design of WT7 to draw on, but there is a dearth of knowledge on how the structure is moving. Neither NIST nor Hulsey understood the motions.
Understanding correctly what we see will then establish criteria for what we can deduce.

It has already been established that the NE corner of the roofline moved in a northerly direction toward the camera:

We also know from the initiation gif above in op, that the entire NE corner was moving; it wasn't a "localized deformation", also known by the fact the entire north face of the structure bowed at onset.
Further, and thanks to Christopher 7 for helping make the case above, we know the perimeter frame was rigid, and not susceptible to easy bending or breaking.

Any theory of how controlled demolition made the structure move as it did, also needs to answer these questions:
1. What energy made the NE part of the structure fall over to the north?
2. Why didn't the SW corner deform commensurate with the NE corner?
3. Why didn't the entire structure likewise fall over to the north with the east part?

Let's stay focused Jeffrey, and see if we figure any way controlled demolition caused what we can see.

Editorial note:
In the interests of viewer orientation and clarity, diagrams that reference what we see should be oriented with the view range up, as in the above illustration, instead of the traditional "North up" orientation.

 

[Joe Hill]

OK, it would also be impossible for all the perimeter to fail at the same time.

Irrelevant, because we know perimeter columns failed in the east part of the structure first, about 3/4 second prior to failure in the west part of the structure.

That is enough to invalidate the NIST hypothesis.

This thread is not about proving NIST right or wrong about anything.
This thread asks the question, "Does it look like controlled demolition?", referring specifically to the perimeter frame, because you claimed descent of the perimeter frame looked like controlled demolition, and ONLY controlled demolition could make it fall like it did.
See my response to Jeffrey above for criteria of this thread.

The NE corner appears to stretch, which of course, it cannot do. But we would see more of the north face if the east end rotated toward the camera.

We can see the east half of the north wall rotating in a direction toward the camera at onset, bowing the entire north face as it does, prior to descent of the structure.


The east part of north wall rotated more toward the camera as the structure descended:

We would not see "more" of the north (east) face at onset. We would see more of it as it continued to arc north.
The motion is explained here. The corner is falling north, and the north east wall is turning to face the camera. Fact.

It would be impossible for the exterior frame to break apart at the beginning of the collapse because it is held together with moment frames which are essentially a steel belt, welded to the columns, all the way around the building on every floor.

I agree 100%.
So, why didn't the SW corner distort at onset?

How did a gravity collapse cause that motion?
answer: It could happen in a demolition or gravity collapse.

A non answer.
You made the claim:

It certainly looks like a planned building implosion, doesn't it?
Nothing else can make a building fall straight down all at once like that.

It is your job to explain how controlled demolition made the structure move as it did. "It could happen" isn't an answer.

 

[Jeffrey Orling]

For sure any explanation of what we see has to be based on an ACCURATE set of observations.

NO you do not need to turn the plans upside down. Plans are drawn with NORTH UP.

Presumably any structural failure of a steel section or steel connection that "naturally" failed... could have failed by supplying "force" with a man made "demolition device" of some sort. So this raises two issues:

1. What members or connections failed - where and when?

2. What sort of "demolition device" could produces the local failure and what "size" was it (force)?

Conspiracy people simple do not answer these two questions. So CD is a black box. If they can't explain what's inside the black box they have failed.

This leaves the discussion of the non CD explanations to address these questions.

All collapses take place over time. An explosive destruction might destroy the entire building. But we can see this did not happen. I believe we can stipulate to the fact that structural failures CAN OFTEN progress through the structure. Some structural failures will not, and the design has a capacity to ARREST the progression of failures. Since 7WTC completely collapse its structural design apparently was incapable of ARRESTING the progression of failures that occurred.

Observations from the outside (1), some reports from firemen and surveyors during the day (2) and of course the structural plans (3) and physics/engineering (4) and forensic evidence (5) gathered post collapse MUST inform the discussion.

It may be possible for multiple failure scenarios and "progressions" to produce the same end result - total collapse. But these scenarios MAY (likely) not produce the same visual sequence of observations. Since we don't have observations from/of the interior we are left to INTERPRET what MAY have been happening.

1. Firemen provided reports or pre collapse concerns. I believe the heard what they believed to be the building "warping" or distorting. This warping was confirmed by a transit survey in the afternoon. Their assessment at some point was that the building was becoming too unstable and would collapse as nothing could be done to stop the "progression" which we can interpret to mean fire and local failures (unspecified). A safety zone was declared which was evacuated of personnel. Exterior observations included fire, smoke (color and locations) emerging from the building... almost exclusively below flrs 14 (???). Heavy black smoke was observed in some locations such as the SE corner below flr 8 (?)

First observed building failure was the collapse of the EPH, followed by the collapse of the Screen Wall structure and finally the EPH. These failures progressed from East to West. The interpretation would be that the structure somewhere below these roof structures failed in an east to west sequence. There were some visual clues (distortions of the window class and spandrel covers) that at least the EPH or parts of the floor/structure below it rapidly descended through (fell) the building's interior.
Next we see the tower drop and at the rate of close to FF for about 2 seconds before the rate of acceleration slowed. It might have even STOPPED accelerating but achieved a uniform velocity. This can be determined using time motion study of a point about 100' below the roof line and measuring its motion.
During the descent we see the north face fold in a kink which seems to extended the entire vertical distance we can see. This suggests (again) that there was a complete collapse of the structure and floors (?) in the region south of the face which moved / folded. What force supplied to IMPUSLE to move this section... while keeping it attached at the fold?

The kink appears to be at the West side of the EPH where it connects to the Screen Wall. The kink appears to be in a line to the West columns 81 - 80 -79 ... mid span of TT1 to column 47 in the exterior moment frame. This suggests that columns 81 - 80 -79 failed FIRST and TT1 and TT2 failed. This may have pulled the East section of the moment frame westward forcing the entire NW corner while pushing the east side of the north face north. If you think of the East side moment frame from col 47 to column 42 (NE corner) to col 28 SE corner to column 23 on the south side... the moment frame is trapezoid shape (missing the "side" from col 23 (south face) to col 47 (north face). It's possible that without the interior "structure" and floor plates to maintain the trapezoid shape... the shape distorted (or broke apart (more likely) at the corners. We can't see it.

Note that there was damage to the center of the South side of the roof from falling WTC1 debris.

BREAK MORE TO FOLLOW

 

[Jeffrey Orling]

Possible progression of interior failures.

1. Axial supports fail - col 79, 80, 81...
2 transfers framed into or supporting col 79, 80, 81...
3. floors supported by transfers (and failed columns)
4. moment frame descends and folds or breaks (can only see north face kink)
5. sections of curtain wall/moment frame falls over top the interior collapse materials.

 

[Jeffrey Orling]

@Joe Hill - The 2+ seconds of free fall of the facade/moment frame... what we see... means that it descended from 100+ feet without resistance. This is the distance from the ground to the top of the 7th floor. So the support of the facade/moment frame "failed" at the 7th floor... and likely the support below floor 7 that may have remained was "structurally not there". It may have been moved laterally... or broken up into component pieces/members.

NOTE the 2 story belt trusses from flrs 5 thru flr 7, the cantilever support of more than 50% of the north face at floor 7. This structure strongly suggests that why the bottom separated at flr 7. But why?

I would suggest that all the falling debris of the interior of the building which had JUST broke free and collapsed INSIDE piled up and pushed outward at the base of the tower... We can see this in the debris pile.. which is spread outside the building's foot print. There was little structural bracing to hold the facade down there in place... especially since virtually all interior column lines had collapsed.




So the 7 story drop is explained by the structure down there.

 

[Jeffrey Orling]

@Joe Hill
It does not look like the east side of the north facade is as you wrote "falling over" to the north.
It looks like the entire section of the facade from the kink east is folded at the kink and rotating counter clockwise (seen from above) around a virtual "hinge" at the kink. The discernible "fold" seems to be slightly west of the east edge of the mech louvers/grillage.

The kink does not appear to be a hard vertical fold... but like a warping curve fold. It looks as if the NE corner/vertical edge where the two faces meet is being pushed north.

I suspect the moment frame is stronger in the vertical direction than it is in the horizontal on... ie the spandrels are "weaker" than the columns.

 

[Joe Hill]

So the 7 story drop is explained by the structure down there.

Again, this thread is not looking for theories on collapse; it is looking for how controlled demolition may/could have caused the motions we see, specifically of the perimeter frame, and especially at onset of the perimeter frame.
Understanding the motion is prerequisite.

It does not look like the east side of the north facade is as you wrote "falling over" to the north.

The NE vertical corner is falling over to the north. The north face is bowing in reaction, with the east half turning more to the camera. We know the NE corner is falling north due to perspective. If it were falling NE, as shown in your diagrams, near 90 degrees to sight line of the camera, it would arc down as it moved. Falling toward the camera, it will appear larger as it falls, thus eliminating the visual downward arc. This diagram is an accurate depiction of perimeter frame motion at onset:

How did controlled demolition make the structure move thus?

 

[Jeffrey Orling]

@Joe Hill Presumable the structural failures could be initiated by destroying key components and initiating a run away progressive failure. So for example the support for TT1 if disabled / destroyed would like cause TTA to fail and this would lead to the floor collapse of the NE quadrant/floors... EPH collapses... the TT1 failure would also pull the transfer girder which runs east-west along the top of the core and supports the 8 MG23 cantilever girders and collapse of the floor areas north of the core... and the progressive failure would arrive at TT3 which would lead to the collapse of the floor areas on the west side of the core.

The columns which support the transfers TT1 and TT2 and the transfers themselves would take some incredibly powerful devices to fail one of them. But once one fails it will take the others down very quickly.