Other things come to mind.
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I wanted to talk about structural collapse for a moment, and this seemed a good place to do it.
Several years ago, one of the barracks on Fort Bragg, NC, near where I lived, was declared unsafe, and evacuated. Safety inspectors came because of a complaint of cracks in a wall, and a mirror shattering for no known reason, and concrete debris in the basement.
As it turns out, one of the concrete support beams in the basement had developed fractures. The inspectors said it can happen with concrete if, for some reason, the concrete sets improperly. If there had been any artillery firing near the main base area on one of the days during construction, vibrations could have caused minute cracks to begin forming, and load stress would have increased those cracks.
Under normal circumstances, a single cracking support column wouldn't have been a problem. But the barracks in question had been build a long time ago, when it was one soldier to a room, with a bed and wall locker, no air conditioning, etc. Since then, they estimate that the live load had more than quadrupled - four man rooms, much furniture, tons of personal belongings, and air conditioning units.
The building stood almost a week after evacuation, as the engineer slated to tear it down were out of the state. Then, one evening, it just fell down. Straight down, in an even collapse.
A lot of the guys asked the same exact questions the CTists do here. The answer was simply that, once a column fails to be able to support its load, it increases stress on surrounding columns. In the case of a building where loads were already exceeded - like this one - many of those columns were damaged as well, though not visibly. They, too, were unable to handle the sudden stress, and failed, transferring even more load to neighboring columns.
This transferral takes seconds.
The result is total structural failure.
The same thing happened in a poorly designed bank years ago - I saw it on a documentary on Discover Channel. The building hadn't properly accounted for dead load, and eventually underwent spontaneous structural failure due to a single column cracking.
In this regard, steel is no different. When steel is weakened by fire to half its strength - a temperature of merely 600 degrees - it loses its ability to bear its assigned load, and that load transfers to other supports. If enough supports fail, all of them will fail; meaning that the building will go from standing to not standing, just like that. No slow sag, no gentle lean, no domino-effect collapses.
Just wanted to talk... don't mind me.
http://www.nytimes.com/packages/html/nyregion/20050812_WTC_GRAPHIC/Nigro_Daniel.txt
Are you calling this man a liar?
<snip>
I said if it had not burned longer than the 2-4 hours steel fire proofing, I would wonder what was up. But since the building burned for 8 hours it was going to fall.
<snip>
And, all of the NYFD was ordered out of the building soon after the first two buildings collapsed....so pull, was not about pulling men from WTC 7, because everyone was out hours ahead of time.
So, the story Larry is telling is 100% BS, except the two words "pull it".Holy crap,
Wowzer. I'm implying that LARRY is lying...and that the Fire chief NEVER said they couldn't contain it. Was that not evident? I'm saying the story Larry is telling is 100% BS. What fire chief would ever say that they (NYFD) couldn't contain a fire? Especially one that is so small you can't even see it from three sides of the building. And, all of the NYFD was ordered out of the building soon after the first two buildings collapsed....so pull, was not about pulling men from WTC 7, because everyone was out hours ahead of time.
I can help a little here.
When the plane impacted the building....
Minor derail.
The quoted time for the fire protection is the duration of protection given in a standard test (can't remember the ASTM no.), so the protection (assuming it is intact) could last for longer or shorter, depending on the severity of the fire.
I think it reasonable that the fire protection applied on site would
a - probably not be applied as diligently as that used in preparing the test samples.
b - may have deteriorated over time since application
end of derail.
Dave
from section 5.3.3 of http://www.fema.gov/pdf/library/fema403_ch5.pdfThe fireproofing material used to protect the structural members has been identified by Silverstein Properties as "Monokote." The Port Authority informed the BPS Team that New York City Building Code Construction Classification 1B (2-hour rating for beams, girders, trusses, and 3-hour rating for columns) was specified for WTC 7 in accordance with the architectural specifications on the construction notes drawing PA-O. According to the Port Authority, the construction notes on drawing PA-O also specified the following:
* Exterior wall columns (columns engaged in masonry walls) shall be fireproofed on the exterior side with 2-inch solid gypsum, 3-inch hollow gypsum, 2-inch concrete or spray-on fireproofing.
* Interior columns shall be fireproofed with materials and have rating conforming with Section C26-313.3 (27-269 current section).
* Beams and girders shall be fireproofed with 2-inch grade Portland cement concrete, Gritcrete, or spray-on fireproofing or other materials rendering a 2-hour fire rating.
The Port Authority stated that it believed the thickness of the spray-on fireproofing was determined by the fireproofing trade for the specific structural sections used, based on the Underwriters Laboratories formula for modifications, which were reviewed by the Architect/Engineer of Record during the shop drawing submittal. Spray-on fireproofing, as required by the code, was also listed on the drawing as an item subject to controlled inspections, in accordance with Section C26-106.3 (27-132 current section). The Architect/Engineer of Record was responsible for ensuring that the proper thickness was applied. The Port Authority had extended its fireproofing inspection program to this building.
from section L3.2 of the NIST WTC7 Interim Report http://wtc.nist.gov/progress_report_june04/appendixl.pdfI1.2 Initiating Components Fail Due to Fire Effects: Fires had been burning in WTC 7 for many
hours, as observed in the photographic and videographic records (see section L.2). The initiating event
may have been caused by fire effects on structural components.
• I2.3 Components on Floors With Burned Out Fires: If the initiating components failed
from fire effects, then locations where fires had burned out by mid afternoon could possibly
been affected by the cooling which occurs after a fire. No fire was observed or reported in
the afternoon on Floors 1–5, 10, or above Floor 13.
− I3.4 Floor Systems Fail: The cooling that may have occurred as the fires burned out in
an area may have generated thermal contraction forces, which may have induced tensile
forces at floor-to-column connections.
o I4.2 Unbraced Columns: If floor systems failed, one or more columns may have
lost lateral bracing. At a floor where fires were noted, interior columns were
comprised of W14x730 cores and reinforcing plates, and could support several
stories unbraced without failure. As an example, the column capacity curve of
column 79 between Floors 5 to 9 is shown in Fig. L–37. Column load-carrying
capacities shown in this figure are based on the AISC column capacity formulas
(AISC 2001). The column is not very sensitive to the number of stories of unbraced
column length, K. This column, which had a service load stress of approximately
21 ksi, would be approaching its load carrying capacity for an unsupported length of
four stories if it was also subject to a uniform temperature of 500 °C.
• I2.4 Components on Floors With Fire: If the initiating components failed because of fire
effects, then locations with uncontrolled fires would be more likely for the initiating event.
From available data of fire locations in WTC 7, likely locations would include Floors 5, 6, 7,
8, 9, 11, 12, and 13. No fires were observed on Floor 5, but the lack of windows and the
presence of fuel systems on the south, west, and north floor areas indicate that fire should be
considered as a possibility on this floor.
− I3.5 Floor System Failure: The fires could have caused the failure of portions of one or
more floor system and its framing connections.
o I4.3 Unbraced Columns: If floor systems failed, one or more columns may have
lost lateral bracing. See I4.2 for discussion.
− I3.6 Columns, Transfer Girders or Transfer Trusses Fail: The fires could have
failed interior columns, transfer girders, transfer trusses, or their framing connections.
o I4.4 Lateral Displacements: Fire effects may have caused column instability
failure by lateral displacements from asymmetric thermal expansion of the floor
system. Such thermally-induced displacements must overcome the restraining effect
of the remaining floor system against further lateral deflection of the column.
o I4.5 Temperature Gradients: Fire effects may have caused the failure of columns
and other components through the forces induced by temperature gradients through
their cross section. Bending and shear forces may be induced that are sufficient to
yield either the column splice or reinforcing plate welds. Analysis of a one-story
segment of interior column 79 indicates that the cover plate weld would begin to
yield at a mean temperature of 490 °C with a 200 °C gradient across the section, as
shown in Fig. L–38. Other mean temperature and gradient combinations may also
cause this type of failure.
o I4.6 Uniform High Temperatures: If initiating event components were sufficiently
exposed to fire effects to be uniformly heated to elevated temperatures, the steel
strength would be reduced below that required to support the load. Figure L–39
shows that for interior columns subject to service loads (shown as approximately
20 ksi of compressive stress), uniform steel temperatures of approximately 570 ºC
would result in column failure.
Um, this is what you call a RAGING inferno:
http://www.youtube.com/watch?v=2KFCNMS5W3o
Now compare it to this:
http://www.youtube.com/watch?v=LD06SAf0p9A
Here's what gets me...it seems that one of the favorite arguments on here, is to say, "Well if it's a CD, than why do virtually ALL of the experts agree with NIST's theory?"
Well, it's not like I've ever agreed with that...and conversely, I haven't even seen 5 "experts" who share similar theories as NIST. Well, actually I haven't looked for them, but supposedly everyone here has.
How does NIST explain the sequential collapse of the core columns? You're saying...you don't need that information in order for you to BUY the official story? This improbable telescoping of the core columns doesn't even raise questions from you? How critical are we thinking...when we over look such glaring omissions and errors? Straight out denying common sense and laws of physics... Where is the critical thinking?
Bonus video dedunking pancake theory:
http://www.youtube.com/watch?v=weqBynRZGG8
Hi einsteen, welcome to the forum.
I just wanted to clarify the NIST's position on "pancaking," since I've already seen this misinterpreted in four different places.
When the NIST uses the term "pancaking," you have to understand that the word has a very precise meaning for them, a meaning different than the general public understands. NIST concludes that WTC 1 and 2 did not experience "pancake collapse," but did experience "progressive collapse."
What is the difference? To NIST, "pancake collapse" means that the weight of one or more floors came loose, landed on a lower floor, the combined stress tore that floor loose, it fell on the floor below, etc. This is NOT what WTC 1 and 2 experienced.
Instead, what NIST is claiming is that, instead of each floor tearing loose, it sagged, pulling inward on the outer columns until they were twisted to the point of failure. The weight then fell on a lower floor, causing it to sag, buckling the outer columns, etc. This is their "progressive collapse."
To any but a structural engineer, the difference is subtle.
The next time you see anyone baldly claim "NIST admits no pancake collapse!!" without attempting to understand what they actually say, you may immediately sense their true agenda. This claim is being used out of context, as well as out of ignorance.
The bursting lower windows and assorted debris travel either (a) with the compression wave in the air contained in the tower, or (b) through the structure as vibrations conducted by steel girders. Both travel at the sound speed in their respective media, e.g. roughly 340 m/s in air and 5100 m/s in steel. Both are considerably faster than the speed of a free-falling object. Your premise is incorrect.
Likewise, there is no evidence of explosions, no recordings thereof, no admission of demolition in WTC 7. If you have evidence that suggests otherwise, you are welcome to present it. You will be the first to do so.
Wrong, Wrong, Wrong! You really have no idea what you are talking about! This is what happened at WTC 7...Retail and Bell,
In this video, Silverstein, says that they decided to pull it because, the fire commander SUPPOSEDLY told Larry, that he (the fire commander) didn't think they could contain the fires in WTC 7. Honestly, do you think a fire commander would ever say...they couldn't contain a fire...especially one that is so small you can't even see it from three sides of the building?
http://www.youtube.com/watch?v=u0scE7bQWdk
And, some of you shouldn't be so mean with the name calling...come on guys.
The Chief Officer then met with his command officer to discuss the building's condition and FDNY's capabilities for controlling the building fires. A Deputy Chief who had just returned from inside the building reported that he had conducted an inspection up to the 7th or 8th floor. He indicated that the stairway was filling with smoke and that there was a lot of fire inside the building. The chiefs discussed the situation and the following conditions were identified:
• The building had sustained damage from debris falling into the building, and they were not sure about the structural stability of the building.
• The building had large fires burning on at least six floors. Any one of these six fires would have been considered a large incident during normal FDNY operations.
• There was no water immediately available for fighting the fires.
• They didn't have equipment, hose, standpipe kits, tools, and enough handie talkies for conducting operations inside the building.
At approximately, 2:30 p.m., FDNY officers decided to completely abandon WTC 7, and the final order was given to evacuate the site around the building. The order terminated the ongoing rescue operations at WTC 6 and on the rubble pile of WTC 1. Firefighters and other emergency responders were withdrawn from the WTC 7 area, and the building continued to burn. At approximately 5:20 p.m., some three hours after WTC 7 was abandoned the building experienced a catastrophic failure and collapsed.
NIST NCSTAR 1-8, page 111
...so "28th Kingdom" are NIST lying in your opinion?NIST said:In WTC 1, the aircraft impact caused damage to the north and south walls, floors, some core columns, and insulation. The subsequent fires caused sagging of the floors on the south side of the office area, where insulation was damaged, and inward bowing of the south wall. The damage to the core columns resulted in local load redistribution to the remaining core columns. The subsequent fire-induced high temperatures caused the core to displace downward from plasticity and high creep strains in high stress and high temperatures. The downward displacement of the core resulted in load redistribution from the core to the exterior walls. With continuously increased bowing, the entire width of the south wall buckled inward. The section of the building above the impact zone tilted to the south as instability progressed horizontally to the adjacent east and west walls. Global collapse occurred as potential energy of the falling upper structure exceeded the strain energy capacity in the deforming structural members.
In WTC 2, the aircraft impact caused damage to the south and north exterior walls, floors, and columns in the southeast corner of the core. The floor damage and the subsequent fires caused sagging of the floors and local floor/wall disconnections, and resulted in bowing and buckling of the east wall. The damage to the core columns and fire-induced high temperatures resulted in local redistribution to the remaining core columns in the southeast corner, which redistributed the core column loads to the east and the south wall columns, as the core leaned toward the south and east. With continuously increased bowing, the entire width of the east wall buckled inward. The section of the building above the impact zone tilted to the east and south as instability progressed horizontally to the adjacent north and south walls. Global collapse occurred when the potential energy of the falling upper structure exceeded the strain energy capacity in the deforming structural members.
The results of the global analysis of both WTC 1 and WTC 2 showed that global collapse of both towers was initiated by the instability of the exterior walls pursuant to their excessive inward bowing which progressed horizontally to adjacent walls.
http://wtc.nist.gov/NISTNCSTAR1-6D.pdf
Yes, the Winsdor Building was raging. All of the steel columns failed as a result.
Typically you try to compare this with a video of the north side of WTC7.
What is all the grey stuff pouring out of the south side in these videos? Could it be smoke? What on earth could cause such a large quantity of smoke to emanate from the building?
Why does a fireman in the first video say 'that's whay he's pulled everybody out of there'??
http://www.youtube.com/watch?v=5WVBAYEEeAg
http://www.youtube.com/watch?v=UN7AEj4szrk&mode=related&search=
http://www.youtube.com/watch?v=51FIPMlrFf4
Each floor is being pulverized one by one.
"Instead, what NIST is claiming is that, instead of each floor tearing loose, it sagged, pulling inward on the outer columns until they were twisted to the point of failure. The weight then fell on a lower floor, causing it to sag, buckling the outer columns, etc. This is their "progressive collapse."
Wow, that's even worse than a pancake collapse. Um, just look at the videos and you will see, everything is shooting outwards..it surely isn't collapsing inwards. Each floor is being pulverized one by one.