Before anybody bashes me, I am not a conspiracy nut. I was talking to
a friend the other night and we discussed this. I would like your
input and expertise, thanks.
I have heard some say that World Trade #7 collapsed "at the speed of
gravity" as opposed to having floor after floor pancake on themselves,
which I gather would be slower. Is that correct?
I am not an architect or an engineer, so I was hoping that maybe some
folks here could illuminate the subject. My point of view, as a
layman, is that the building would not collapse so perfectly because of
debris from the twin towers. Am I correct or is there a possible
explanation that architecture people might be able to describe? Or
If this has been covered before then I apologize, but I would really
like to learn more about this. Thank you for your time in educating
Huh? Gravity is not a "speed" =:-p
The acceleration due to Gravity is, on earth, if I remember correctly, 32
feet per second. Gravity has no "speed".
The rate ("speed") at which something falls is a function of its mass, air
resistance, and any other intervening factors (such as pillars and their
composition, and so on).
IOW, it seems to be a non-argument from the get-go. Sounds like the one
"argument" is something along the lines of instantaneous vaporization :p .
It makes no sense. Not to me, at least.
Yup, you're right, per second, per second.
The context implied near the surface of the earth (or at least, as the
saying goes, close enough thereto for government work), since it was the
WTC. Mass and distance from the center of that mass are part of the
Gravity equations, tho' I can't remember at all any more what the
accelertion due to gravity is for other planets.
I almost never use metric any more, haven't for some years, so I've
unfortunately forgotten much of it :(
Once the floors start pancaking down, do you expect the next floor down
to have a longer elapsed time to failure or shorter? Shorter of
course. The perceivable change in acceleration, or slowing down of
gravity forces due to resistance of the building's structure, is hardly
something someone can look at and say, "Yep, that sure looks like
around 10 meters/second^2."
Unless there was greater and greater structural support at each consecutive
floor below, which is not to necessarily say that this is or was the case.
Yes, there should be natural chaotic variability to mess with predicability,
so I think pancaking buildings won't fall according to gravity alone.
There'll be issues of syrup-consistency, which can often be correlated to
its temperature and sugar content for example, as well as how much butter
there is, how light and fluffy each cake is, and maybe even the angle at
which the cook whacks the stack, and what he uses to do so, etc..
And speaking of stack-whacks, here's a little tune/video:
--Wing of The Plane, by Severed Heads
for a general overview of how WTC 7 collapsed.
It doesn't really make sense to distinguish between floor pancaking and
global collapse, as buildings are not monolithic structures, but
structures made up of separate of parts (columns, beams, struts,
floors, cladding, etc.) Depending on the design, failure of any of the
critical structural parts can cause partial collapse, partial
pancaking, global collapse, global pancaking, or nothing at all.
WTC 7 was a particularly unique example because unlike the vast
majority of other buildings, this building had a structural system that
transferred load from the new building system to an existing structural
grid of a prior building. See the above document. Just from the line
drawings you should be able to grasp that WTC 7 had some particularly
critical columns, unlike most other skyscrapers where there is some
As for a 'neat collapse', most buildings will little structural
redundancy, particularly in the center core, will collapse onto their
own footprint. given the nature of their component construction. Large
buildings don't act like trees.
The other fires were likely electrical fires or fires caused by the extreme
heat of the tower 1 collapse. As you say, the final reports don't conclude
that the diesel fuel fire made any difference if it was even burning when
the global collapse occured.
Yes, that's the likely major cause along with all the other weaknesses
caused by the other fires... the structural collapse occured just as the
tower 2 collapse happened. Extreme heat from the fires weakened major
structural components. Also recall that the vibrations caused by the tower
1 collapse could understandably have loosened fireproffing and maybe even
some structural connections.
here's another interesting report with really good structural analysis:
??? If I recall WTC 7 collapsed 6-7 hours after both Twin Towers had
come down, like 4 or 5 in the afternoon.
Reading the final reports of WTC 1 and 2 is very illuminating, and also
depressing. Some rather astonishing details.
Yeah, I used to have a really good view of the towers and had a really good
view of them coming down. By then everyone was on their rooftops following
the action. I remember standing there with my binocs and seeing that gaping
hole and telling my neighbors that the towers were going to come down
because I knew how they were built... to give you an idea of how the whole
event made people lose focus and reason, most thought that the NYFD would be
able to get the fires out, others actually thought that if they fell, they'd
fall like trees and might "hit us" even though we were 2 miles away, others
thought there were 100000 people working at the WTC and they ALL perished
when the planes hit... it was, needless to say, a crazy day, er, make that
a crazy eon in NYC. Now it feels like it was decades ago - ancient history
except for those little reminders that keep creeping in like that movie that
just opened yesterday...
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