What the World Trade Center Building Designers Said: Before and After 9/11

What the World Trade Center Building Designers Said: Before and After 9/11

An analysis of contradictions in statements by Building Designer Leslie Robertson

By Arabesque[1]

Update: 03/12/2007

Another Quotation from John Skilling added about the possibility of controlled demolition destroying the World Trade Center buildings in 1993.

Before 9/11

“A previous analysis [by WTC building designers], carried out early in 1964, calculated that the towers would handle the impact of a 707 traveling at 600 mph without collapsing[2]

(Between Early 1984 and October 1985):

“However, O’Sullivan consults ‘one of the trade center’s original structural engineers, Les Robertson, on whether the towers would collapse because of a bomb or a collision with a slow-moving airplane.’ He is told there is ‘little likelihood of a collapse no matter how the building was attacked.’”[3]


“[Building designer] John Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire. A lot of people would be killed.” But, he says, “The building structure would still be there.[4]

“The analysis Skilling is referring to is likely one done in early 1964, during the design phase of the towers. A three-page white paper, dated February 3, 1964, described its findings: “The buildings have been investigated and found to be safe in an assumed collision with a large jet airliner (Boeing 707—DC 8) traveling at 600 miles per hour. Analysis indicates that such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact.” However, besides this paper, no documents are known detailing how this analysis was made.”[5]

Skilling - a recognized expert in tall buildings - doesn't think a single 200-pound car bomb would topple or do major structural damage to a Trade Center tower. The supporting columns are closely spaced and even if several were disabled, the others would carry the load. ‘However,’ he added, ‘I'm not saying that properly applied explosives - shaped explosives - of that magnitude could not do a tremendous amount of damage.’ Although Skilling is not an explosives expert, he says there are people who do know enough about building demolition to bring a structure like the Trade Center down. ‘I would imagine that if you took the top expert in that type of work and gave him the assignment of bringing these buildings down with explosives, I would bet that he could do it.[6]


Leslie Robertson, one of the two original structural engineers for the World Trade Center, is asked at a conference in Frankfurt, Germany what he had done to protect the twin towers from terrorist attacks. He replies, ‘I designed it for a 707 to smash into it,’ though does not elaborate further.”[7]

[Leslie Robertson:] “The twin towers were in fact the first structures outside the military and nuclear industries designed to resist the impact of a jet airplane.[8]

[Frank A. Demartini:] The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.” Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.[9]

Sept 3-7, 2001—just before 9/11

“The Boeing 707 was the largest in use when the towers were designed. [Leslie] Robertson conducted a study in late 1964, to calculate the effect of a 707 weighing 263,000 pounds and traveling at 180 mph crashing into one of the towers. [Robertson] concluded that the tower would remain standing. However, no official report of his study has ever surfaced publicly.”[10]

After 9/11

“The engineer who said after the 1993 bombing that the towers could withstand a Boeing 707, Leslie Robertson, was not available for comment yesterday, a partner at his Manhattan firm said. ‘We're going to hold off on speaking to the media,’ said the partner, Rick Zottola, at Leslie E. Robertson Associates. ‘We'd like to reserve our first comments to our national security systems, F.B.I. and so on.’”[11]

“The building owners, designers and insurers, prevented independent researchers from gaining access—and delayed the BPAT team in gaining access—to pertinent building documents largely because of liability concerns.”[12]

“[The] National Institute of Standards and Technology (NIST), in 2005 state that it has been ‘unable to locate any evidence to indicate consideration of the extent of impact-induced structural damage or the size of a fire that could be created by thousands of gallons of jet fuel.’”[13]

“In 2002, Leslie Robertson wrote: “To the best of our knowledge, little was known about the effects of a fire from such an aircraft, and no designs were prepared for that circumstance.”[14]

“[Leslie Robertson:] I support the general conclusions of the NIST report… The [WTC] was designed for the impact of a low flying slow flying Boeing 707. We envisioned it [to be like] the aircraft that struck the Empire State building [during] WW II. It was not designed for a high speed impact from the jets that actually hit it Yes there was a red hot metal seen [in the WTC rubble] by engineers. Molten—Molten means flowing—I’ve never run across anyone who has said that they had in fact seen molten metal, or by the way if they had seen it, if they had performed some kind of an analysis to determine what that metal was.” Steven Jones in discussion With Leslie Robertson [MP3] by KGNU Radio, Denver, CO, Oct 26, 2006


Robertson has made some glaring contradictions in his statements.

· Robertson claims that the building was designed to only survive plane crashes at speeds of 180 mph. Interestingly he made this claim only a few days before 9/11.[15] A quote by Building Designer Skilling indicates that “A previous analysis, carried out early in 1964, calculated that the towers would handle the impact of a 707 traveling at 600 mph without collapsing”.[16] Robertson must resolve this apparent contradiction. It is a very suspicious statement given the fact that it would be reasonable to consider the maximum speed of a plane flying into the Twin Towers. Is it possible that Robertson was asked to leak this “deliberately misleading information” just before 9/11? However, this is just speculation. Also suspicious is the fact that he said in 1984-5 that there was “little likelihood of a collapse no matter how the building was attacked.”[17]

· Robertson says that the building was not designed to survive jet fuel fires: “To the best of our knowledge, little was known about the effects of a fire”. This claim is suspicious for two reasons: why would they design the towers to survive plane crashes without considering the jet fuel? And more importantly, John Skilling claimed in 1993 that they did consider the jet fuel when they designed the buildings.[18] Given this fact, which statement is more likely to be correct about jet fuel fires being considered?

· NIST is also contradicted when they claim that there was noevidence to indicate consideration of… thousands of gallons of jet fuel”. This statement is clearly false. See John Skilling’s statement: “Our analysis indicated the biggest problem would be the fact that all the fuel (from the airplane) would dump into the building. There would be a horrendous fire… The building structure would still be there.[19]

· In interview with Steven Jones, Robertson claims that he had “never run across anyone who has said that they had in fact seen molten metal.” This statement is extremely suspicious considering the fact that Robertson himself claimed to have seen it in a published news report! This contradicts his own statement about seeing molten metal: “Leslie Robertson, the structural engineer responsible for the design of the WTC, describes fires still burning and molten steel still running 21 days after the attacks.”[20]. As well, substantial eye-witness testimony supports observations of Molten Steel.[21]

· Robertson is also incorrect when he says that “if they had seen [Molten Steel, they had not] performed some kind of an analysis to determine what that metal was. This statement is false. FEMA analyzed samples of the molten steel.[22] However, NIST did not even mention the molten steel and called it “irrelevant to [their] investigation.”[23] This could have simply been a mistake by Robertson.

Is Robertson being pressured to lie and make false statements? Was he asked to leak a false statement just before 9/11 about the speed of the planes having an impact on their destruction? Are these contradictions by accident or mistake?

A news report stated that he wanted to give his opinion to the FBI before making his comments public. This in itself is not overly suspicious—but his contradictions are. No clear answers to these and similar questions can be obtained through speculation alone—Leslie Robertson must account for these himself. If another 9/11 investigation is obtained, it is clear that Leslie Robertson will have to answer these and other relevant questions.



[1] http://www.911blogger.com/blog/877

[2] Paul Thompson’s Complete 9/11 Timeline: (see February 27, 1993)

[3] http://www.cooperativeresearch.org/entity.jsp?entity=leslie_robertson

See here: [Glanz and Lipton, 2004, pp. 227; New York County Supreme Court, 1/20/2004]

[4] [Seattle Times, 2/27/1993]

[5] [Glanz and Lipton, 2004, pp. 131-132; Lew, Bukowski, and Carino, 10/2005, pp. 70-71]

[6] [Seattle Times, 2/27/1993]

[7] [Chicago Tribune, 9/12/2001; Knight Ridder, 9/12/2001]

[8] [Robertson, 3/2002; Federal Emergency Management Agency, 5/1/2002, pp. 1-17]

[9] http://www.prisonplanet.com/articles/november2004/141104designedtotake.htm

[10] [Glanz and Lipton, 2004, pp. 138-139, 366]

[11] “Believed to Be Safe, the Towers Proved Vulnerable to Jet Fuel Fire”



[12] [US Congress, 3/6/2002; Associated Press, 3/7/2002]

[13] [National Institute of Standards and Technology, 9/2005, pp. 13]

[14] [Robertson, 3/2002]

[15] [Chicago Tribune, 9/12/2001; Knight Ridder, 9/12/2001] These articles the day after 9/11 make clear the fact that this statement was made before 9/11: “Les Robertson, the Trade Center's structural engineer, spoke last week at a conference on tall buildings in Frankfurt, Germany”.

[16] Complete 9/11 Timeline: (see February 27, 1993)]

[17] http://www.cooperativeresearch.org/entity.jsp?entity=leslie_robertson

See here: [Glanz and Lipton, 2004, pp. 227; New York County Supreme Court, 1/20/2004]

[18] [Seattle Times, 2/27/1993]

[19] [Seattle Times, 2/27/1993]

[20] [SEAU News, 10/2001] This fact was observed by David Ray Griffin and Paul Thompson’s Complete 9/11 Timeline.

[21] http://georgewashington.blogspot.com/2005/12/why-was-there-molten-metal-under.html

[22] See here for pictures and comments in FEMA’s report mentioning the melted steel:

“Although virtually all of the structural steel from the Twin Towers and Building 7 was removed and destroyed, preventing forensic analysis, FEMA's volunteer investigators did manage to perform "limited metallurgical examination" of some of the steel before it was recycled. Their observations, including numerous micrographs, are recorded in Appendix C of the WTC Building Performance Study. Prior to the release of FEMA's report, a fire protection engineer and two science professors published a brief report in JOM disclosing some of this evidence.” 1

“The results of the examination are striking. They reveal a phenomenon never before observed in building fires: eutectic reactions, which caused "intergranular melting capable of turning a solid steel girder into Swiss cheese." The New York Times described this as "perhaps the deepest mystery uncovered in the investigation."2 WPI provides a graphic summary of the phenomenon.”

“The severe corrosion and subsequent erosion of Samples 1 and 2 are a very unusual event. No clear explanation for the source of the sulfur has been identified. The rate of corrosion is also unknown. It is possible that this is the result of long-term heating in the ground following the collapse of the buildings. It is also possible that the phenomenon started prior to collapse and accelerated the weakening of the steel structure. A detailed study into the mechanisms of this phenomenon is needed to determine what risk, if any, is presented to existing steel structures exposed to severe and long-burning fires.”

Evidence of evaporated steel as reported by the New York Times:

“Engineers have been trying to figure out exactly what happened… ‘Fire and the structural damage… would not explain steel members in the debris pile that appear to have been partly evaporated’” from:

Glanz, James (2001). “Engineers are baffled over the collapse of 7 WTC; Steel members have been partly evaporated,” New York Times, November 29. 2001.

[23] See here: http://911research.wtc7.net/reviews/nist/WTC_FAQ_reply.html#13

The 9/11 Commission Report

Of course, the opinions of these experts don't count as evidence (at least, I don't think they do), they do reinforce the fact that no one expected a total collapse of the towers. The report makes several references to people who did not think the towers would collapse, and only one real reference to the possibility they would:

“They also received advice from senior FDNY chiefs that while the building might eventually suffer a partial collapse on upper floors, such structural failure was not imminent. No one anticipated the possibility of a total collapse” (291).

“To our knowledge, none of the chiefs present believed that a total collapse of either tower was possible” (302)

Here's the one case of someone who expected a total collapse, and naturally it is from an anonymous "engineer":

“At about 9:57, an EMS paramedic approached the FDNY Chief of Department and advised that an engineer in front of 7 WTC had just remarked that the Twin Towers in fact were in imminent danger of total collapse” (302)

“Prior to 9:59, no NYPD helicopter pilot predicted that either tower would collapse” (304)

From 10:03 to 10:29, “at least three firefighters heard evacuation instructions which stated that the North Tower was in danger of ‘imminent collapse’” (307

“According to two eyewitnesses, however, one senior FDNY chief who knew that the South Tower had collapsed strongly expressed the opinion that the North Tower would not collapse, because unlike the South Tower, it had not been hit on a corner” (309)

One could add to this list the metal workers in Metal of Honor, who to a man state that they did not expect the building to collapse.

Evidence of Manipulation

While I agree that statements on their own are not necessarily evidence:


11 features of controlled demolition analyzed by David Ray Griffin


Thermite analyzed by Steven Jones and his controlled demolition hypothesis


No previous history of fire collapses—ever


Massive Eyewitness testimony


Experts designed the buildings to survive plane crashes


Other evidence

Results in devastating cumulative evidence proving that 9/11 was an inside job.  Proving that he has lied only adds more evidence that 9/11 was an inside job.

The statements by Robertson are very important in my opinion because lying involves motive.

A probable motive could be that the perpetrators are forcing him to say these things. He could be threatened, or even paid to lie. In an investigation we can question him to see why he said why he said it and who told him to say it (if applicable). Maybe he is just making honest mistakes. I’m inclined to doubt that. His statements are very suspicious. From there we can trace this to the perpetrators.

Perhaps he could even admit the truth about why he said these things. In any case it helps 9/11 truth by finding the answers. Every single piece of evidence is useful to make a stronger case to force a new investigation.

“We're an empire now, and when we act we create our own reality."

I'm not questioning your

I'm not questioning your evidence. Somebody blew those mf*ckin towers to bits. I just wanted to add similar evidence to your list, while qualifying what I was adding.

Not everyone thought the 2nd tower would survive

I thought you were implying that Robertson’s statements don’t count as evidence. I misinterpreted your statement. However, I would suggest that fire experts would know a thing or two about buildings collapsing due to fire. 

It’s interesting that not everyone thought the 2nd tower was going to remain standing after the first one fell: 

“‘Chief, they're evacuating the other building; right?’ He said, ‘No.’ . . . I said, ‘Why not’ They blew up the other one.’ I thought they blew it up with a bomb. I said, ‘If they blew up the one, you know they're gonna blow up the other one.’ He said, ‘No, they're not.’ I said, ‘Well, you gotta tell them to evacuate it, because it's gonna fall down and you gotta get the guys out.’ . . . He said, ‘I'm just the Battalion Chief. I can't order that.’ . . . I said, ‘You got a f___ing radio and you got a f___ing mouth. Use the f___ing things. Empty this f___ing building.’ Again he said, ‘I'm just a Battalion Chief. I can't do that.’ . . . Eventually this other chief came back and said, ‘They are evacuating this tower.’ . . . And sometime after that . . . I watched the north tower fall.”


William Reynolds, Firefighter in conversation with a Firefighter Battalion Chief

“At that point, a debate began to rage because. . . many people had felt that possibly explosives had taken out 2 World Trade, and officers were gathering companies together and the officers were debating whether or not to go immediately back in or to see what was going to happen with 1 World Trade at that point. The debate ended pretty quickly because 1 World Trade came down.”


Christopher Fenyo, Firefighter describing a conversation after the first tower fell

“We're an empire now, and when we act we create our own reality."

from the oral history of William Reynolds

"After a while, and I don't know how long it
was, I was distracted by a large explosion from the
south tower
and it seemed like fire was shooting out
a couple of hundred feet in each direction, then all
of a sudden the top of the tower started coming down
in a pancake."

The case Alex Schibli

sorry, this is all in german, as Schibli is Swiss...

Here's a article confirming DeMartini:


Gerhard Wisneski picks it up:


This should be a mail from Schibli to a debunker, I can not confirm it's authenticity, as I found no email adress of Schibli to contact him.

If it's neccesary I'll do my best to translaste it.

Sehr geehrter Herr Sperling,
vielen Dank fuer das E-mail. Ich gehe mit Ihnen einig, dass es nicht recht ist, Aussagen von verstorbenen Opfer zu missinterpretieren und zu missbrauchen. Ich glaube auch nicht an eine Verschwoerungstheorie, habe aber weder Lust noch Zeit mich mit unsachlichen Argumenten und Polemiken auseinander zu setzen. Es ist nicht recht, wenn der Migros-Artikel und meine Auesserungen als Belege fuer die Spreng-Theorie benutzt werden.

Ich kannte die Konstruktion des World Trade Centers (WTC) recht gut. Bis 1975 arbeitete ich fuer den Erbauer des WTC (Tishman Construction Company,) als Project Engineer. Von 1998 bis 9/11/2001 hatte ich mein Bureau im Nord Turm, im 82. Stockwerk und arbeitete ich fuer "The Port Authority of New York & New Jersey" (Besitzerin des WTC). Meine Aufgabe war, die technische Beratung fuer diverse Umbau Projekte, hauptsaechlich in den Untergeschossen.

Der Grund fuer den Einsturz des WTC wurde gruendlich untersucht und eindeutig abgeklaert.

Meine persoenliche kurze Zusammenfassung der Ursache fuer den Einsturz des WTC:
Die Flugzeug-Einschlaege durchtrennten tragende Stahl-Saeulen und verursachten starke Beschaedigungen am Hitzeschutz der Stahltraeger (der Hitzeschutz war in schlechtem Zustand) und beschaedigte die Sprinkleranlage (ist total ausgefallen) und beschaedigte Fluchtwege, Etc.. Die Stahltraeger wurden geschwaecht durch Erhitzung wegen dem Dauerbrand gleichzeitig auf mehreren Stockwerken wuetete. Es war viel brennbares Material vorhanden, welches gleichzeitig mit dem Brennstoff der Flugzeuge gezuendet wurde. Der Ausfall der horizontalen Boden- Traeger verursachte die "Knickung" (Start des Einsturzes) der hitze-geschwaechten Trag-Saeulen, welche zusaetzliche Lasten uebernehmen mussten, wegen dem Ausfall anderer, vom Flugzeug durchschlagenen, tragenden Saeulen. Danach war es die Wirkung der Gravitationkraft (physikalisch nachvollziehbar).

Mein Freund Frank DeMartini war Architekt und war ein Super Construction Manager; er war kein Statiker oder Wissenschaftler und hat auch keine Studie verfasst! Er war es, der massgeblich beteiligt war, bei der Wiederherstellung des World Trade Center nachdem 1993 eine Lastwagen Bombe im 3. Untergeschoss in der Sued/Ost Ecke des Nord Turmes explodiert war. Frank - eine grosse Persoenlichkeit - hatte enormes Vertrauen in die Statik des World Trade Centers, hatte er doch gesehen wie das Gebaeude den Bombenanschlag von 1993 ueberstehen konnte. Ich bin ueberzeugt am 11. September 2001, haette er das Gebaeude auch frueher verlassen, wenn er den Schaden nach dem Einschlag der Flugzeuge von aussen gesehen haette.

Leider kann das Verhalten von Hochhaeuser nicht getestet werden, wie man das Verhalten von Automobile testen kann, um die Sicherheit bei Unfaellen zu erforschen.

Ich hoffe Ihnen mit meinen Angaben zu helfen.

Freundlich Gruesse

Alex Schibli, P.E.

Nice job, Arabesque

Thanks for putting this together.

Robertson made another comment in his debate with Steven Jones that shocked me -- that NIST was not chartered by Congress to model past the point of initiation of collapse, and that there was no reason for them to do so.

NIST and Robertson

Yes I agree. However, he’s only following the NIST line after all. The NIST report admits that the report is only a “collapse initiation” report. It assumes that total collapse is logical, when in fact it is not logical. The NIST report is irrelevant on this point alone. The most important question about 9/11 is why did the WTC building completely crumble to the ground in a pile of dust. NIST didn’t even attempt to answer it.

Since he is also supporting NIST’s “jet fuel” hypothesis it makes sense that he is also supporting their “pre-collapse” theory. In my mind this further suggests he is being manipulated to support the official story with his contradictory statements.

The NIST report is very strong evidence for the 9/11 truth movement because of its glaring disregard for the scientific method. In my opinion, it will be very important evidence to force a real investigation.

The fact that he supports the NIST report by contradicting his previous statements makes an even stronger case that has been manipulated to lie as documented in my analysis.

“We're an empire now, and when we act we create our own reality."