Willravel

Someone obviously hit the building. It was just odd that they found one of the terrorists passports at the wreakage. I am say it is possible that someone else was doing the flying. I obviously do not have near the expertise that you have on this subject, so I will let it rest at this: there is just as much possibility that Islamic terrorists were flying, as oppsed to someone else. I conceede.

The fire that was responsible was supposed to melt the frames, both inside and out, according to the report. Why did it collapse from the top? Why did the top floor come down before the point of impact collapsed? The footprint of the core supports, relative to the outer supports, has no connection to the amount of structural failure bringing it down. If that sentance didn''t make sense, let me put it this way: the core has a smaller footprint, but that doesn't mean it takes less structural failure to bring it down. The outer supports by themselves are much easier to take down due to pressure or melting. The center is actually stronger than the outer supports.

Remember the "official" position? Remember those "heated and deformed bolts," which we're to believe gave way, almost simultaneously? In chapter two of the FEMA report, it is revealed that the bolts of the "weakened" floor beams were lateral (sideways) supports; not vertical. The vertical support plates (L-shamed "hanger brackets") for the floor joists were welded!

By inference, we are to believe that the 'corner' bolts (heavier insulation with greater adhesion) ALL lost their thermal insulation, that no heat was radiated away by the steel-on-steel contact and that no significant volume of heat was ventilated out through the shattered windows - along with all that smoke. The "manufactured presumption" is that the heat totally accumulated to produce the cited temperatures - not from burning jet fuel, per FEMA - but from burning furniture, interior finish materials and paper! With all that 'contained' heat, the cooler outer steel walls are supposed to have heated and expanded sideways - independently of the heated & expanded steel floor joists... - That's not how fire physics operate.

FEMA also glosses over another detail - the analysis/emphasis should have been on the stronger MAIN floor trusses, not the "transverse" (90-degrees to the main joists) floor joists. The floors were supported by an "x-y" grid of vertical supports, not a single row of trusses - as otherwise suggested.

The reality is that the expansion of the heated/expanded floor trusses and joists would have added strength, not taken it away! The heated floor structural elements would have 'snugged-up' to the cooler outer walls. The outer walls [cooled by external convective air currents], being vertically channeled, would not have "expanded-away" from the steel floor joists; leaving the floor panels to collapse.

While any expansion of the trusses and joists would have definitely affected the outer walls, the effect should have been neligible. The imagery of the outer walls being the last to collapse attests to the validity of that argument.

This brings us to another interesting point - the windows ran to the top of the full ceiling - thus the heat accumulation would have been relatively negligible, given the open ventilation from the volume of broken windows - evidenced by the wind carrying the smoke away. The internal components and the outer walls would not have been subject to a massive "heat treatment," relative to a reasonable time which should have been required to cause ANY significant collapse.

These counter-arguments radically diminish the proposition that the rigidity of the cement floors and their deeply corrugated steel containment 'pans' were somehow 'destroyed,' with the subsequent 'dead weight' causing the floor joists to abruptly 'bow' downward and inward and collapse. The 'official' presentation also ignores the insulated steel pan acting as a contact 'firewall' for the cement floor, as well as an effective 'heat-sink.' It must not be forgotten that the deep corrugation of the steel pans constituted additional vertical support, similar to rebar.

Again, the obviously limited time of intense heat exposure limits the inevitablity of a collapse - in part; or in whole.

A heat induced floor collapse may be possible - for limited numbers of local floor segments, affecting one floor at a time. Given the surviving thermal insulation - in some part - around the steel, the heat could NOT have been universally distributed over an entire single floor, let alone over ten floors - in the case of the North Tower, in particular.

It's elementary logic that any significant heat would have caused a weakening of the steel. However, it's ludicrous to believe that the heat uniquely accumulated, versus ventilated, so as to disastrously diminish the strength of industrial steel - in such a short period of time.

It must also be considered that the elevator shafts and the stairwells acted as chimneys. The fires on the floors above the impact floors attest to the probability of those fires being started by the "chimney effect." What started as a conduit for flame, later became a conduit for ventilation.

Such ventilation would also have acted to cool the 47 vertical columns, diminishing any tendency to weaken & buckle - to any appreciable extent. Again, it's necessary to remember how quickly the collapse occurred - if the purported cause-and-effect was factual.

In evidence of the heat escape, one picture of the events shows a woman STANDING at the edge of the burned-out North Tower entry hole (Illustrated in figure 2-15 of the FEMA report). If she could have stood upright at that station, it's academic that the internal temperatures couldn't have been hot enough to produce an abrupt event - such as the nearly instant collapse.

To be fair, the pictures do show what is apparently a well-fed conventional fire on a floor approximately two stories upward from the woman. Again, the building was designed and 'rated' to deal with that temperature level.

The aircraft impact would have taken out approximately 30 exterior shell columns, weakening the face of the building. However, it is clear that the exterior collapsed in consequence of the building core collapsing, with the interior material having enough lateral energy to shatter the outer shell, as the core collapsed - with the cement flooring shattering into so much dust.

Returning to the argument of the mechanics of a basement "core collapse," the lowest floor in the buildings would only have traveled the distance of the missing “basement” segment - whatever that level may have been. [For the sake of argument, again, let’s call that eight feet - literally at the last level.] The lower floor would have traveled eight feet, then stopped. However, with that collapse (transmitted the full length of the core – to the very top of the building) the upper segment would experience an acceleration effect in the classic ‘mass-times-acceleration’ equation. Thus, with the aircraft impact and fire damage, at the top, the weakened and ‘segmented’ upper portion would be dynamically converted into a “plunger.” Gravity did the rest. *

To keep the concept of such an operation simple, it’s necessary to entertain the idea also that ONLY the base of the columns were rigged with Thermite charges. With enough induced force (collapse), the upper “core” column attachment joints (bolts/welds) could conceivably shear/shatter in a vertical 'accordion' effect from the downward accelerating mass.

In all the images of the collapse, there is nothing seen to suggest that the segmented upper "caps" (in their entirety - including the outer walls) collapsed onto the lower floors (making contact with the lower floors) - until impacting the ground. The South Tower "cap" tilted onto the lower floor, it did not pancake onto that floor. What is NOT seen is a solid initial "crunch," of the upper floor collapsing onto the lower segment.

Ordinarily, one would expect to see a solid initial "crunch." Absent such an event, logic goes to the argument, "No pancake from above; no pancake below." The "caps" could only BOTH fall - "in formation" - if the lower sections were falling at an equal speed - identically timed. Both sections would need to be subject to the same "trigger event" for that kind of timing. TWO such occurrences are too much for coincidence.

Maybe. In this area I am still quite unclear and I am not done researching. This was working off the asumption that Islamic terrorists were not flying. If they were (as I said above), then this is possible.