WildCat
NWO Master Conspirator
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All those engineers are morons, not smart like Derek Johnson! And Derek doesn't even need an engineering degree!
He just needs someone to answer his questions...
Invitation to Derek Johnson to discuss his ideas
- Thread starter tfk
- Start date
He just needs someone to answer his questions...
Oystein
Penultimate Amazing
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Tom is. As you know.
You just need to agree to some reasonable terms of a civilized debate among engineers.
Among these terms must be your willingness to provide answers.
You know this.
Your feigning to have no challenger is another lie. And you know it is a lie.
Derek Johnson
Thinker
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Hmm, not so much Oystein. I know this:
“Primarily for the east tenant floor, when a floor beam thermally expanded, the beam displaced the girder at the interior end of the floor beam but did not displace the exterior frame at the other end of the floor beam.” - NCSTAR 1-9, p. 526.
Now that is amazing. If the beams are unrestrained at one end, how can they develop the compressive force necessary for buckling to occur?
"Many of the east floor beams on Floors 12, 13, and 14 failed by buckling, as shown in Figure 11-27 and Figure 11-35” – NCSTAR 1-9, pp. 526-27
Can the beams push the girder laterally (and break the intersecting girder's 4-bolt seated connection at column 79) if they have buckled in compression?
Your (any twoof-crusher will do) explanation of these truly amazing
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LashL
Goddess of Legaltainment™
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Hey, Bill
This is fabulous to hear. I was talking on the phone with my friend, Ron Wieck, the other day (you might remember him as he used to be a member here) and I suggested to him that you would make a splendid guest on Hardfire and asked him if he would be willing to do a show, "An Evening with Bill Smith" and giving you a choice of either being interviewed one on one by Ron, or presenting your unique insights into firefighting to a member of the FDNY. He enthusiastically agreed. Now, that conversation was based on your performance in one of the "building seven" threads, but this above is even more awesome.
I'm pretty confident that he would accommodate this as well, and give you the opportunity to present your strong case and your extremely strong case. So, what do you say? Surely, you'd take the opportunity to spread your case to a wider audience and go on the record live, right?
(Note: I don't want to derail this thread but I also didn't want to start a new thread as it might look like a call-out thread, and a short aside and some thread 'drift' is permissible, so that's why I posted this here when I saw your post above.)
RedIbis
Philosopher
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Why? Isn't Ron able to get someone a bit more prominent on his show? No offense to Bill, but I suspect that the invitation you extend is more for the comedic possibilities, as opposed to any sincere discussion that might take place on Hardfire.
Why don't you ask Derek instead?
tsig
a carbon based life-form
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People employ engineers to answer questions.
triforcharity
Banned
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Why don't you write a paper proving NIST wrong, get it published in a REAL journal (Bentham and JO911S are NOT real journals) and be a hero for the "Truth" movement?
What's stopping you? GO buddy go!! CHOP CHOP!! Time's waisting!
MIKILLINI
Incromulent Logic
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And you really are in your own world.
triforcharity
Banned
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here you go there champ.
http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR%201A.pdf
Page 87, second bulletpoint.
Now,
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Edited for civility
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triforcharity
Banned
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Listen, I know the other dolts of the 911 bowl movement love to play games, and ask silly questions, and act like they are all coll and ****, but you're acting like a little kid. Screaming and screaming about something that is nothing.
NIST specifically states that the NORTH WALL fell for aproximately 100' at approximately g.
What did I get wrong? What did Tom get wrong? Did NIST say something different? Did they say it fell at 1000 x's G? How about 100 x's BELOW g?
Did they say the ENTIRE building? NO!
FFS man, get a grip! Stop being an ignorant troofie, and let it go. God damn. I would expect this from my 6 year old. Not a grown man.
WildCat
NWO Master Conspirator
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Bill actually has a theory, unlike Derek and you, who are "just asking questions" and make no claims.
No-claimers make for a boring show, while Bill is a comedic genius.
triforcharity
Banned
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Edited by LashL:
Edited response to moderated content
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Carlos
Critical Thinker
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Explain us why thermal expansion cannot cause the failure of those elements.
Do you agree the concrete slabs was not designed to resist that shear stresses? Do you agree that axial expansion of a beam causes shear forces on the slabs transmited by "shear connectors"?
I was listening to your presentation and you brought up Silverstein and "pull it". You mislead your audience implying he called for 7 to be destroyed, when it is clear he is talking about fire support will be pulled. This is fraud.
Discuss why you deliberately try to mislead people and make up what is essentially a lie.
The Big Dog
Unregistered
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Uh, keeping within the snarky comments of your truthiness, you seem to contend that all of the beams failed by buckling? Even though that is clearly not what is said. Hmm, thermal expansion causes breaking of the intersecting girder's 4-bolt seated connection at column 79 and thermal expansion causes buckling of beams. Wait a tick! Perhaps you are missing something in NIST's analysis.
Although your argument from incredulity is spectacularly truthy.
How is the federal review action coming? Ha! just kidding! There is none, you are to busy being snarky on the internet.
Carlos
Critical Thinker
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What about these parts?
"The exterior frame underwent minimal lateral displacement when floor beams thermally expanded, since the exterior framing with moment connections was much stiffer than the interior girder"
(...)
"Buckling in the floor beams was due to the combined effects of loss of lateral restraint, increased axial loads due to thermal expansion effects and gravity loads from the floor slabs"
Two important things.
1 - The beams were not unrestrained.
2 - The buckling was caused by a combination of differents effects. Do you know the difference between buckling and "lateral buckling"?
SRW
Master Poster
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Derek, help me out with this, I am not an engineer so it could be I am missing something. The way I read that paragraph it seems to say that the floor beam expanded toward the interior girders causing displacement on the interior girders. Due to the interior girders being weaker than the exterior frame .
Where does it say that the beams are unrestrained at one end?
Using logic? Way too much fun. Logic and rational thinking is prohibited in 911 truth, and Gage has banned it.
You are addressing a person who give talks, presentations, with known lies as main points. He claims Leslie Robertson, the chief structural engineer for the WTC towers, said molten steel was flowing in the WTC. Mr. Robertson never said it, Derek preaches it from his pulpit of delusions and lies.
Derek Johnson
Thinker
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Hi Carlos & SRW:
"1 - The beams were not unrestrained." - they were bolted on each end, but NIST removes the shear studs from the girders, and makes statements to suggest they expanded to push the intersecting girder off its seat. Trouble is they say elsewhere they buckled. Oops, their bad.
"2 - The buckling was caused by a combination of differents effects. Do you know the difference between buckling and "lateral buckling"?"
To your inquiry, and thank you for the engagement:
"Buckling in the floor beams was due to the combined effects of loss of lateral restraint, increased axial loads due to thermal expansion effects and gravity loads from the floor slabs"
This is exactly why the "buckling-expanding" beam initiated is easily debunked. You can't have this both ways. If the floor beams buckle due to any one of or combined effects of lateral restraint, increased axial loads etc., their ability to push for a "walk off" of the girder to column 79 (2 above, 2 below) 4 x 7/8" A490 bolt connection just does not exist. If so how? The intersecting girder wins if the beams buckle. Please explain in detail if you disagree. If not, I'll assume you do agree.
I think so. And you're right, according to NIST's statements. First, Ron Brookman S.E. wrote a detailed analysis on NIST's woo, entitled:
The NIST Analyses: A Close Look at WTC 7, dated March 26, 2010. It shines light on a few things. Thank you Ron. Please read it and please enjoy it.
Failure of the floor framing at the east end of floor 13 was blamed for initiating the series of events that led to complete collapse. A discussion of existing floor plans and combustibles includes the following statement:
"…there was some uncertainty regarding the nature of some spaces. Notably, the U.S. Securities and Exchange Commission (SEC) and American Express occupied all but the east side of the 13th floor, and NIST was unable to find people who recalled the nature of the unoccupied space." NCSTAR 1-9, p. 48.
It is unlikely that those who managed the tenant spaces of this 47-story office building could not recall, or could not find out, who or what occupied the specific location where the collapse initiation was said to occur. Apparently NIST did not use their subpoena power to obtain this information from the building owner.
According to NIST the floor framing failed as a result of several factors including failure of shear studs, buckling of beams, and ''walk off'' of girders due to unrestrained thermal expansion of perpendicular beams.
"Primarily for the east tenant floor, when a floor beam thermally expanded, the beam displaced the girder at the interior end of the floor beam but did not displace the exterior frame at the other end of the floor beam." NCSTAR 1-9, p. 526.
"Many of the east floor beams on Floors 12, 13, and 14 failed by buckling, as shown in Figure 11-27 and Figure 11-35." NCSTAR 1-9, pp. 526-27.
Of course the beams were not unrestrained, but by NIST's statements (and some help from computer model's 'relative displacement'), the beams both buckled and pushed the 79 to 44 girder. Which is it? And how can you have both? Either the beams buckle (figure 11-27, 11-35 and figure 8-27) or they expand to break the seated connection. Pick one, you can't have this both ways. If the beams are unrestrained at one end, how can they develop the compressive force necessary for buckling to occur? Alternatively, how can the beams push the girder laterally if they have buckled in compression?
Reasons listed for the loss of lateral support to columns 79 through 81 include:
"The buckling failure of the east floor beams and exterior columns was caused by restrained thermal expansion and failure of the shear studs along the beam length." NCSTAR 1-9, p. 537.
What exterior columns? It is not clear what buckling failure of exterior columns is referred to in the preceding statement. I thought the interior columns failed well before the exterior...but whatever. And NIST previously stated "…the beam displaced the girder at the interior end of the floor beam but did not displace the exterior frame at the other end of the floor beam." NCSTAR 1-9, p. 526.
If thermal expansion of the floor beams did not displace the exterior frame, then how would buckling of exterior columns occur?
The thermal expansion of the WTC 7 floor beams that initiated the probable collapse sequence occurred primarily at temperatures below approximately 400° C (750° F). NCSTAR 1A, p. 59.
Unrestrained thermal expansion of 52 foot long beams was blamed for pushing a girder off its bearing seat at column 79. This linear expansion is about 3.5 inches at 400° C, but this is a full two inches short of the 5.5-inch lateral displacement required for loss of vertical support. ''Walk off'' is the term NIST used to describe the failure mode where a beam or girder moved axially or laterally off its bearing seat losing all vertical support. The walk-off failure was assumed to be complete when lateral displacement of the beam or girder end moved past the point at which the beam web was aligned vertically with the edge of the bearing seat. (NCSTAR 1-9, p. 488.) One of the least ''state-of-the-art'' features of the complex analysis performed by NIST is the means by which they accounted for the lateral walk-off failure of the girder at column 79, and convincing documentation of this triggering failure mode is nonexistent. Why?
"A control element (COMBIN37), a unidirectional linear spring element with the capability of turning on and off during an analysis, was used to model walk-off." NCSTAR 1-9, p. 480.
"The travel distance for walk off was 6.25 in. along the axis of the beam and 5.5 in. lateral to the beam." NCSTAR 1-9, p. 482.
Since the COMBIN37 element could only account for displacement in one direction (axially), what accounted for displacement in the lateral direction?
"A control element was used to model beam walk-off in the axial direction. Beam walk off in the lateral direction was monitored during the analysis." NCSTAR 1-9, p. 482.
Monitored by what?
NIST summarized the floor framing failures that led to collapse initiation, and lateral girder walk off at columns 79 and 81 was the failure mode allegedly responsible for the start of collapse. (NCSTAR 1-9, p. 536.) Where are the analytical results that substantiate walk-off failures at columns 79 and 81? Where is the output data from the ANSYS analysis that confirms the lateral walk-off failures?
Oh that's right, it would jeopardize public safety of course...got it.
And the shear studs, by which NIST derives it's differential displacement woo. Different NIST reports say different things about shear studs on girders. If any steel was retained we might know this, but 100% of WTC 7 was China-recycled. Mr. Bloomberg thought that computer simulations were good enough. Who needs to test the evidence during a
http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR 1-1.pdf
Also, NCSTAR 1-1 p.14 states that "Most of the beams and girders were made composite with the slabs through the use of shear studs. Typically, the shear studs were 0.75 in. in diameter by 5 in. long, spaced 1ft to 2 ft on center."
By contrast
"In WTC 7 no studs were installed on the girders." NCSTAR 1-9, p 346.
By additional contrast
NCSTAR 1-9 p. 543 shows shear studs where shown on plan, and a "typ interior beam or girder diagram" with shear studs on top. Further, there is another error right on Figure 12-4, it says "Based on Fabrication Shop Drawings (Cantor 1985)." Cantor was the engineer of record and did not prepare the fabrication shop drawings. It should say "....(Frankel Steel Limited 1985)."
Finally, There was no steel debris examined, so how does NIST know there were no shear studs on the 13th-floor girder spanning between columns 44 and 79? Wouldn't the contract documents and structural plans settle this? FOIAs are pending.
NCSTAR 1-9 Section 8.8 describes the finite-element analysis of a partial singlefloor framing system bounded by interior column 79 and exterior columns 44, 42 and 38. This is the area blamed for the collapse initiation; this is the subsystem model that predicted failure of shear-studs and girder connections, beam buckling and excessive lateral displacement of a girder at column 79—all triggering collapse initiation.
The purpose of this subsystem analysis was to demonstrate ''possible failure mechanisms that were used to develop the leading collapse hypothesis further." (NCSTAR 1-9, p. 353.) Girder and beam temperatures were assumed to be 500 degrees and 600 degrees Centigrade respectively, and the slab was assumed to remain unheated. NCSTAR 1-9, p. 349.
"No thermal expansion or material degradation was considered for the slab, as the slab was not heated in this analysis." NCSTAR 1-9, p. 352.
Why not? The concrete floor slab could not possibly remain unheated in an atmosphere where steel beams supporting the slab were heated to 600 degrees. The beams were coated with thermal insulation, so the air temperature would have been even hotter than 600 degrees. The duration would also have to be longer than what photos indicated.
"The boundary conditions and temperatures were selected to create maximum shear forces on the stud connectors and beam and girder connections." NCSTAR 1-9, p. 349.
*scratches hair under tin foil hat*
Huh?
The NIST partial-floor model did not allow the slab to expand thermally with the steel beams, and neglecting thermal expansion of the slab has the effect of imposing additional relative displacement on the shear studs connecting the concrete to the steel. This subsystem analysis formed the basis for special connection elements used in the global analyses as described in the following passages.
"The failure modes in this model [the partial floor] were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses." NCSTAR 1-9, p. 353.
"These results helped to guide the development of special connection elements…that captured the salient features and failure modes of the various types of connections used in the floor system of WTC 7." NCSTAR 1-9, p. 359.
NIST states that ''even though steel and concrete have similar coefficients of thermal expansion, differential thermal expansion occurred between the steel floor beams and concrete slab when the composite floor was subjected to fire." (NCSTAR 1-9, p. 490.) This relative displacement occurred in the ANSYS model, and no physical testing was done to verify its magnitude in the steel-and-concrete structure.
Of course NIST didn't take steps to maximize the destructive effects of any relative displacement due to thermal movement. Who would ever even think to do such a thing?
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