The 9/11 Forum

I'd like this thread to focus on the basic WTC 1 and 2 structural connections, core, flooring and perimeter, and simple, practical ways to break or weaken them before 9-11-01 or during a supposed demolition masked behind a terrorist attack.


Contributors to this thread are free to dabble in the use of AP or a thermite coating against these connections if they wish, but my weapon of choice may be a good automotive socket wrench set and a 5 inch angle grinder, who knows?


THE WORKSPACE






Unless you have wings and are invisible, to structurally weaken the perimeter you would work from within the structure.



Welcome to the space above the standard t-bar ceiling in standard commercial office space in most any modern US building. Anyone in electrical, plumbing, HVAC, ect sees the same type of trusses, dropped ceiling, metal roof spaced spaced just as you see here regularly.

This is the standard view from an 8 foot ladder inside a dropped ceiling. All building components are visible and within reach.

A dropped ceiling is in most every similar office area in the US because it allows total accessibility to the mechanic to all building components while shielding all those raw, unattractive pipes, ducts and structural components from view.



THE CONNECTIONS




How hard would it be to bust this upper connection and just leave the floor "sitting" on a plate in the weeks leading up to 9-11-01?


I'm sure you get the idea.

Can this graphic be accurate? is that the bolt connection?

How time passes. I saw this thread the day it was started, and intended to comment. And here it sits.

is that the bolt connection?

Guess so. My mind reels. WTF? Isn't a 5/8" bolt what you use to bolt the head onto a lawnmower engine?

Stunned. I still don't know what to say. Now wonder the building behaved like a fluid.

Pyro-bolts? Not very loud. Unzip a whole floor without sounding much different than it happening... through some other means. Do two half-perimeters on adjacent stories and it's history.

Major_Tom wrote:

Can this graphic be accurate? is that the bolt connection?

I think the graphic is accurate.

However, the trusses at each location were actually double trusses.

The 32 inch double trusses were on 80 inch centers and the floor pans, with installed trusses, were pre-fabricated in 20 foot wide sections. If you look at video showing them being off loaded from trucks or brought up to their installation location by crane you will see 20 foot wide sections of floor pan with two sets of double trusses in the middle and a single truss on each end. When butted next to another 20 foot wide pan the single truss on the end would be situated right next to the end truss of the adjacent floor pan, creating a double truss there also.

Not counting the damping unit bolts each floor had about 700 bolts and 350 welded joints permanently attaching the floors to the brackets on the columns.

The welded joint would have to be ground away and the bolted joints could have been removed with nobody knowing the difference, as the load was essentially vertical shear under normal circumstances. Even though it would take a significant amount of time to perform this task, you raise an interesting point here.

OneWhiteEye wrote:How time passes. I saw this thread the day it was started, and intended to comment. And here it sits.

is that the bolt connection?

Guess so. My mind reels. WTF? Isn't a 5/8" bolt what you use to bolt the head onto a lawnmower engine?

Stunned. I still don't know what to say. Now wonder the building behaved like a fluid.

Pyro-bolts? Not very loud. Unzip a whole floor without sounding much different than it happening... through some other means. Do two half-perimeters on adjacent stories and it's history.

Actually replacing the bolts with pyro-bolts is something that might have been possible. But there would still be the problem of the welded gusset plate on the perimeter side and the direct weld of the truss top angles to the bracket on the core side.

T_Szamboti wrote:But there would still be the problem of the welded gusset plate on the perimeter side and the direct weld of the truss top angles to the bracket on the core side.

Yes, true. Most of the strength remains.

T_Szamboti wrote:Not counting the damping unit bolts each floor had about 700 bolts and 350 welded joints permanently attaching the floors to the brackets on the columns.

That is probably just to the perimeter columns. These floors, like doughnuts, were also connected around the core (the hole in the middle) so you can probably add another 500 bolts.

Easiest way to cut/shear off these bolts is to blow out the perimeter columns sideways. In order not to make it too obvious, you produce a lot of smoke ejection just prior that.

The first natural target I have in mind is the inside of the 98th floor spandrel plate (WTC1). This is totally accessible using an 8 foot ladder just inside the windows above the dropped ceiling.


Severing method would be a variation of heat-weakening: Embrittle a line of perimeter columns just along the bottom edge of the spandrel plate. Kick the spandrel plate outwards to initiate failure.

The strip of spandrel metal and 98th fl flooring provides the perfect channeling of possible ejections by the devices inwards.


Generalized "kick-out" devices need to only serve the purpose of providing minimal outward displacement over an embrittled line.


Einsteen used the word "catalyst" when referring to initiating devices.

This is why WTC1 doesn't sound like the Landmark Tower demo. Devices during collapse initiation need only provide a slight displacement along embrittled lines or pre-broken connections.

Bombs need not break and displace as in a normal demo. They only displace.



When I realized that the upper perimeter is being displaced out and over the lower perimeter during collapse initiation much easier demo scenarios became possible.


Let's say I want to cut the weld with a 5" angle grinder. Can anyone describe the typical barriers one can expect when accessing the weld for the gusset plates?

Easiest way to cut/shear off these bolts it to blow out the perimeter columns sideways. In order not to make it too obvious you produce a lot of smoke ejection just prior that.

Yup.

Even though it would take a significant amount of time to perform this task, you raise an interesting point here.

Along only 1 or 2 floors I don't think so.

I will approach the problem as a contractor doing the job rather than as an academic. Contractors can often muscle through gritty problems in half the time it would take an academic to ponder a solution.

Major_Tom:

Interestingly, if you were to weaken the line of perimeter columns along both the top and the bottom of the spandrel plate, you could potentially encourage a failure mode as depicted by NOVA in the 'Odd Illustration' thread.. Or am I not following what you are describing?

Major_Tom wrote:The first natural target I have in mind is the inside of the 98th floor spandrel plate (WTC1). This is totally accessible using an 8 foot ladder just inside the windows above the dropped ceiling.


Severing method would be a variation of heat-weakening: Embrittle a line of perimeter columns just along the bottom edge of the spandrel plate. Kick the spandrel plate outwards to initiate failure.

The strip of spandrel metal and 98th fl flooring provides the perfect channeling of possible ejections by the devices inwards.


Generalized "kick-out" devices need to only serve the purpose of providing minimal outward displacement over an embrittled line.


Einsteen used the word "catalyst" when referring to initiating devices.

This is why WTC1 doesn't sound like the Landmark Tower demo. Devices during collapse initiation need only provide a slight displacement along embrittled lines or pre-broken connections.

Bombs need not break and displace as in a normal demo. They only displace.



When I realized that the upper perimeter is being displaced out and over the lower perimeter during collapse initiation much easier demo scenarios became possible.


Let's say I want to cut the weld with a 5" angle grinder. Can anyone describe the typical barriers one can expect when accessing the weld for the gusset plates?

Easiest way to cut/shear off these bolts it to blow out the perimeter columns sideways. In order not to make it too obvious you produce a lot of smoke ejection just prior that.

Yup.

Even though it would take a significant amount of time to perform this task, you raise an interesting point here.

Along only 1 or 2 floors I don't think so.

I will approach the problem as a contractor doing the job rather than as an academic. Contractors can often muscle through gritty problems in half the time it would take an academic to ponder a solution.

I was initially thinking the bolt and weld removal would need to be done on a significant number of floors to get things going. However, even if it was up to six or seven floors you are right that it wouldn't be a big deal then. That could probably be done by a half dozen guys in a week's time, almost certainly in two weeks.

I am not sure how accessible the welds on the perimeter side gusset plate would have been. Was concrete poured on top of them? I don't think access to the welds on the core side would be a problem with a small right angle grinder. The bolts were accessible on both sides.

T_Szamboti wrote:I was initially thinking the bolt and weld removal would need to be done on a significant number of floors to get things going. However, even if it was up to six or seven floors you are right that it wouldn't be a big deal then. That could probably be done by a half dozen guys in a week's time, almost certainly in two weeks.

I am not sure how accessible the welds on the perimeter side gusset plate would have been. Was concrete poured on top of them? I don't think access to the welds on the core side would be a problem with a small right angle grinder. The bolts were accessible on both sides.

I for one have always wondered about the strength of the seat angles. Each of these had roughly 5 tons of gravity load. Here's another view of the floor construction with connections to the exterior. I think the gusset plates would have been covered by concrete, but they don't really provide much vertical strength, but they would inhibit lateral shifting of the floors.

Major_Tom:

Interestingly, if you were to weaken the line of perimeter columns along both the top and the bottom of the spandrel plate, you could potentially encourage a failure mode as depicted by NOVA in the 'Odd Illustration' thread.. Or am I not following what you are describing?

Similar but more simple. The NOVA images are totally unreal in that there is no seam which exists horizontally along the perimeter to pull in and break. The prefab perimeter sections are staggered.

I assume that the illustrator had almost no knowledge of the actual structures and the illustration is a simple mistake. If not, it is disinformation.

NOVA is a pull-in whereas the upper perimeter is slightly kicked out over the lower portion along most every face in reality.

But you need a seam in the perimeter before kick-out can work (it's not easy to cut a cage). There are at least 2 ways to make a seam: Along bolt connections (hence zig-zag) or you embrittle a line of inherent weakness (like just under the spandrel plate) in a horizontal line across the face.

I have found indications of both types weakened seams that I have shown in other threads (WTC1 perimeter behavior revealed and WTC2 perimeter action recorded).

I have also found the tendency for the upper block perimeter to kick out and over the lower block on at least 6 of the 8 existing faces, a phenomenon inconsistent with natural collapse, the seam creation and kick-out would be quite consistent with that which was observed to occur.

http://www.youtube.com/watch?v=-y2vgETA8gs go to 3:40 (deep link doesn't work?)

you will see some white falling dot and......

Major_Tom wrote: The NOVA images are totally unreal in that there is no seam which exists horizontally along the perimeter to pull in and break. The prefab perimeter sections are staggered.

I assume that the illustrator had almost no knowledge of the actual structures and the illustration is a simple mistake. If not, it is disinformation.

A prefab perimeter section, say 3 m wide and 11.1 m high, with its three, 0.4x0.4 m, square box columns held together by three 1 m high spandrel plates say 3.7 m apart (leaving 0.6x2.7 m window openings between columns/spandrels), is evidently much stronger than the three little brackets that the floor trusses are bolted to.

To suggest, as NOVA does, that the floor trusses can pull in the perimeter section and that the latter 'snap's (fractures across the columns), as pointed out by Dr. Sunder of NIST, is ridiculous.

It seems the spandrels are simply bolted/rivetted together but what about the columns? There is a hole in the column below the top. Did they insert some sort of backing on the inside and one-side welded the columns together from outside?

The WTC2 E side seam is a different case. It is the only face I've studied where the top sheet is not kicked out over the lower sheet.

P1, remember the first two rows of forceful ejections separated by about 3 floors on this face? In the WTC2 perimeter action thread I am trying to give an alternative explanation to these ejections as the cutting of a perimeter seam along staggered bolt connections. Notice how at about 3:40 in the video the first forceful row of ejections happens about 2 floors below the line being pulled in. I'm suggesting that could be one stage of a perimeter seam cut. The top edge of the lower sheet can be seen falling away (in peeling, not freefall motion) broken cleanly along staggered bolt connections with no trace of buckling.

Both ejection rows and the top of the peeling sheet are seen in the short clip below.

http://www.youtube.com/watch?v=nLHGLI1Ihv0

To suggest, as NOVA does, that the floor trusses can pull in the perimeter section and that the latter 'snap's (fractures across the columns), as pointed out by Dr. Sunder of NIST, is ridiculous.

It is either a simple mistake or disgusting disinfo.