Do we agree the towers were designed to withstand jetliner crash?

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations. The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

Can you show me the calculations or the certifying board that certified them? How about show me the standard according to any of the professional societies for how such a calculation would even be done? Any codes or statutes or legal standard for such a calculation? A textbook? A whitepaper? Anything?

Non Believer said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations. The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

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• They did withstand the impacts.
• 99.99% of the ASCE/ASME members as well the worldwide structural engineering and materials science community, including Leslie Robertson, are in agreement with the official story.
• The B-25 impacted the ESB with less than a sixtieth(1/60) of the kinetic energy of AA11/UA 175s impact. Apples/oranges.

Do you think the structural engineering community is wrong? Why?

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations. The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

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LashL said:

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Oh no...not again.

leslie robertson: "the circumstances of the attacks were beyond that which we considered in the design (Discovery channel- "WTC: Anatomy of a collapse" maybe someone can back that up)

the rest of your assertions are already addressed by people far more competent than I.

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners.

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that were presumed lost in a fog at an approach speed of about 180mph, flights 175 and 11 were each travelling over 400mph

Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations.

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robertson said the reason they didnt calculate anything for the fires was because they lacked the computer power to perform such calculations when the towers were designed

if such calculations were impossible at the time then its a good they were not done

The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners.

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demartini was not involved in any way in the design or construction of the towers, his assertations hold little if any weight

For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

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compare the size, weight, and speed of a b25 to the 767s that hit the WTC on sept 11 and youll (hopefully) see how pointless this argument is

I would stop trying to explain physics to this guy. In his mind he's thinking "BIG PLANE MAKE BIG EXPLOSION"

Non Believer said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations. The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

Click to expand...

You know Martini is not the original designer; Robertson is; Robertson is the expert in this case!

The airliner was not fully fueled for the design impact of the 707. It was a slow speed lost in the fog, landing fuel. That puts the plane in a low fuel state.

The design impact was 5 to 7 times less then the impacts of 9/11.

Darn, a factor of over 5! The old phrase speed kills come to mind as we look at the impact of the 707 vs the terrorist fully fueled 767s.

So the towers did survive the equal of 5 to 7 impacts all rolled into one high speed impact on 9/11.

The fuel was 10,000 gallons, the heat equal of 315 tons of TNT! (wonder if that would start uncontrolled fires that could weaken steel? Yes {real experts answer their own questions})

The fires were not fought, the fires were started by 10,000 gallons of fuel, the fires had a big giant hole to feed the fuel of the WTC with Oxygen. The smoke was not really that black, it was so massive to be like a dark cloud. The fires grew and weaken the steel. The massive impacts displaced the wall board protecting the core and exterior sections. Darn, there went the 2 hour safety factor of the fire proofing, blown away. (do not believe fire does not destroy steel buildings; the steel only portions of the Madrid fire exploded in a way and fell all over the place; destroyed; fact is large structural wood does better in fires than steel)

IMPACTS:
B-25 – 41 pounds of TNT (big one)
Design – 184 pounds of TNT (WTC design for 707 impact)
Flight 11 – 1311 pounds of TNT
Flight 175 – 2066 pounds of TNT

B-25 at Empire State Building impact 84,967,480 joules (41 pounds of TNT {you mentioned this one, what a small impact!!!!SMALL})


Want some more from the engineer that built the WTC?

The original structural engineering Leslie E. Robertson design for an aircraft impact, but it was a slow speed landing configuration, less energy at impact than the 9/11 impacts!

The original structural engineering Leslie E. Robertson said it was the 10,000 gallons of fuel they failed to consider (besides the order of magnitude larger crash). Based on the design of the WTC, it is amazing the towers remained standing as long as they did, surviving a impact blast 10 times greater than design.



Leslie E. Robertson, , said:
"The twin towers of the World Trade Center were designed to resist safely the impacting by the largest aircraft of that time...the intercontinental version
of the Boeing 707. In no small measure because of the high level of
competence of the men and women of LERA, each of the towers resisted the
impact of an aircraft larger than the 707. Yes, fire brought down the towers,
but the structural integrity created by the engineers of LERA allowed perhaps thousands of persons to evacuate the buildings prior to the fire-induced collapse." http://www.engr.psu.edu/ae/WTC/LesRobertson.html


Leslie E. Robertson, , said: on being hit by a commercial jet -
" It appears that about 25,000 people safely exited the buildings, almost all
of them from below the impact floors; almost everyone above the impact floors perished, either from the impact and fire or from the subsequent collapse. The structures of the buildings were heroic in some ways but less so in others. The buildings survived the impact of the Boeing 767 aircraft, an impact very much greater than had been contemplated in our design (a slow-flying Boeing 707 lost in the fog and seeking a landing field). Therefore, the robustness of the towers was exemplary. At the same time, the fires raging in the inner reaches of the buildings undermined their strength. In time, the unimaginable happened . . . wounded by the impact of the aircraft and bleeding from the fires, both of the towers of the World Trade Center collapsed."

http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument


Leslie E. Robertson, , said: more on design for jet impact –
" The two towers were the first structures outside of the military and nuclear
industries designed to resist the impact of a jet airliner, the Boeing 707. It
was assumed that the jetliner would be lost in the fog, seeking to land at JFK
or at Newark. 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. Indeed, at that time, no fireproofing systems were available to
control the effects of such fires."

http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument

More on Robertson -

http://interactive.wsj.com/fr/emailthis/retrieve.cgi?d=SB1002665463810757240.djm

http://www.engr.psu.edu/ae/WTC/LERPresentation.htm

It is, IMHO, vitually impossible to economically design a structure such as the WTC towers to withstand the impact of a passenger aircraft, simply because the chaotic nature of such an event would produce a huge number of scenarios based upon the speed, angle of impact, height of impact, angle of aircraft, point of impact etc etc etc.

The best they could do is calculate the possible amount of structural damage produced by a plane of a certain size travelling at a certain speed and hitting above a certain height. Those parameters are based upon the size of the largest aircraft likely to hit the structure, the reasons for it hitting (an accident rather than deliberate) establishing the speed which could be expected, and the fact that it is most likely to hit above a certain height (having to clear other buildings in the vicinity).

But the chaos of the event post impact makes it nearly impossible to know how much damage would be caused to joints between members which are then weakened by this damage, and how much fireproofing would be removed by wreckage flying through the building.

Because of these factors it is entirely reasonable to accept that those towers were not designed to withstand impact from a fully fueled modern passenger jet travelling at, or near, it's top speed.

nonbeliever said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners.

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(emphasis mine)

I am fairly certain that, if the people who were in charge of the project have said that the towers were designed to resist the force of an airliner crash, then that is the case. However, I do take issue with some of the assumptions you have made in your post. Likely, they are caused by simple lack of knowledge in the industry, and hopefully, I can help you out somewhat in that area.

There are many various fields of engineering which are involved in the design of a skyscraper such as the ones we had at the World Trade Center. They include, but aren't limited to: Structural Engineers, Civil Engineers, Mechanical Engineers, Electrical Engineers . . . with specialties ranging from steel frame design, to fire protection, to plumbing systems, lighting, sprinklers, air conditioning . . . you name it. Just about any sort of system you will find in a building has its own engineer, or team of engineers (far more likely in a project of this scope) who is responsible for its design. These design teams might be large or small, but they are largely autonomous. The Plumbing Design engineer isn't really concerned with the Structural Design engineer, unless it has direct impact on what he is doing, and the Structural Design engineer isn't overly worried about what the HVAC designer is doing, either.

Typically, you have an architect, project manager, or some sort of committee that is in charge of coordinating all of the various systems to make sure that they are working together. They might tell the structural engineer that they need the structure to withstand the force of a plane of X mass travelling at Y velocity, in addition to the wind loads, and to overdesign the structure for that purpose. It's easy enough for him to do, since the force he's trying to overcome is easily calculable given those parameters. However, he's not overly concerned with the subsequent fires, as that is someone else's job, and if he takes into account that the planes might be fully fueled upon impact, he is likely only going to use that to add mass to the object in his calculations.

Even if the Coordinator is really on the ball, and asks if the Fire Protection Engineer might design his fireproofing such that it is able to withstand fires as hot as might be caused by the fuel, even for several hours, that engineer is probably not going to take into consideration the force of impact, since that is in the Structural Engineer's realm.

So, on the one hand, you have a structural engineer who says the building was designed to withstand that impact. From his perspective, it probably was. You might even say these towers did remarkably well considering that the passenger jets were larger than anything available when the Twin Towers were designed, and almost certainly travelling at a greater velocity than had been originally planned. And, as others have already pointed out, they did resist that initial force, and did not topple immediately.

On the other hand, you have the person responsible for the fire protection who might say that the fires themselves should not have been able to weaken the structure as much or as quickly as they did. And, from his perspective, that is also true. Unfortunately, the fireproofing in the impact zones, which is where the structures ultimately failed, was ineffective because of the type of event that started the fires. The spray-on batts were blown away by the explosion, and sprinkler lines were severed. It was the combination of circumstances, not the individual parts, which caused the collapse.

In any event, you have quotes, shown by others to be at least partly out of context, by only a couple of people who were involved with the design of the building. In reality, for a project of this magnitude, you would have dozens of engineers from all of these various fields working over several years.

Non Believer said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists...

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This is the point where I stopped reading and just let my eyes slide right to the bottom of the page.

The towers were designed to cop a hit from a 707. Now, fuel and weight are factors but two more important factors are speed and size.

The buildings had in fact been designed to withstand the impact of the largest airliner of the day, the Boeing 707, in the event one was lost in fog while looking to land. The modeled aircraft weighed 263,000 lb (119 metric tons) with a flight speed of 180 mph (290 km/h), as in approach and landing. The 767s that struck the World Trade Center were travelling at 490mph and 590mph respectivley. As energy increases with the square of speed, the 767s that hit the towers had a kinetic energy more than seven times greater than the modeled impact. Nonetheless, the impacts alone did not cause the towers to collapse.

The original poster must have gone to bed!

Karl Johannes said:

leslie robertson: "the circumstances of the attacks were beyond that which we considered in the design (Discovery channel- "WTC: Anatomy of a collapse" maybe someone can back that up)

the rest of your assertions are already addressed by people far more competent than I.

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No ,no ,no you're not supposed to look at that statement from Mr Robertson only the part that appears to disagree with the so called official version!

Even if someone proved that the towers were designed to survive such an impact, this would disprove a conspiracy.

Conspirators trying to fool the world would not deliberately place a striking anomaly at the center of their plan. They would not want anything to draw undue attention to the event. So the idea would never have gotten past the planning stage.

Here's the scenario:
Conspirator 1: Let's make it look like airliners brought the towers down.
Conspirator 2 (viciously smacking Conspirator 1 upside the head): Don't be an idiot! People would wonder why the towers fell. They would research the matter, find out we staged an impossible event...and we'd be caught. We're trying to make it look real, not give the game away! AHHH! (Smacking stupid old Conspirator 1 upside the head a few more times.)

I realize the assertion has been debunked quite thoroughly in this thread. My point is that--even if we lay technical matters aside--the conspiracist scenario falls apart logically.

Non Believer said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations. The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

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A B25 has a max take-off weight of about 16 tons. It is a twin engine piston engine machine with a max speed of 275mph.

http://www.acepilots.com/planes/b25.html

Probably, the accident at Empire State Building played a role, but when you build two 1300ft buildings in a metropolis with several busy airports around, a plane collision will be an obvious part of your risk assessment.

We can discuss exactly what kind of plane collision the towers were designed to withstand till the cows come home, but obviously, such a design would have to be entirely theoretical. It could not be tested, and computers available at the time could not have simulated it.

This is one of the strange contradictions of 911 CT adherents: They reject every word of the NIST report as ridiculous, but when the designers of a building 30 years ago claimed that it could withstand a plane crash, it MUST be true.

They also said the Titanic was unsinkable, remember? (Oh, I'm sure there is a CT about that, too ).

Hans

Non Believer said:

I think the evidence is clear that the majority of the engineers of the towers have gone on the record that the towers were designed to withstand crashes of fully fueled jetliners. Leslie Robertson's famous quote that the coincidence theorists point to says that he was not aware of any calculations that were done on the resultant fires from a crash. He does not say that he knew there were no such calculations.

The late John Skilling is clearly on the record that the towers were built to withstand such an event, as is the late Frank Demartini who died in the towers on Sept 11. De Martini can be seen on video claiming that the towers could withstand multiple jetliners. For those of you not aware of the history. The empire state building was struck by a B-25 bomber that was lost in the fog in 1945. Because of this event the designers of the towers intentionally designed the towers to withstand such an impact.

Click to expand...

And withstand the impact they both did, with an impact energy about 4 -7 times that of a 707 at Terminal Control Area speeds. If you bother to look at any FAA chart, and the Airman's Information Manual, put out by the FAA, the FAA restricts speeds in a TCA to below 250 knots, and typically within the approach paths to an airport below 200 kts. There's a valid design spec for an architect, and an engineer, estimating the expected impact load for a 707 that inadvertently hits a tall building.

The top speed of a 757 or a 767 is around 450 kts, gear up, throttles firewalled. Even if weights were similar, 707 is a bit smaller, the force of impact is easily estimated, where m is Mass and V = Velocity

KE = 1/2 m*V^2.

Do the math, or better yet, STFU.

What the towers didn't handle too well was the fire afterwards. You will see from the various films and photos, the towers remained standing after impact. Burning. If you bothered to read the NIST analysis (not just the executive summary) you'll see where the heat weakened the structural members, both those damaged and those undamaged by the impact.

What is unknown, and unknowable perhaps, is the degradation, or state of repair, of the fireproof coating on the structural members of the two buildings.

If you want to pursue a worthwhile goal, I suggest you file a FOIA request, and agree to pay for copying services, for a copy of the blue prints of both WTC 1 and WTC 2. These should have been on file with the insurance company, and whatever authority issued the building permit. That would be, perhaps, the city of New York, the borrough of Manhattan, the State of New York. Of course, the owners of the buildings as well as the Port Authority have an interest in those drawings. Hundreds of pages, you might want to stop paying for porn and save your pennies to afford this request.

There's a place to seek the truth, in the form of facts.

DR

Enlightenment said:

I would stop trying to explain physics to this guy. In his mind he's thinking "BIG PLANE MAKE BIG EXPLOSION"

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or possibly " must kiss L C b............."

No one on earth would expect a global collapse due to a plane before 9/11. Ok it happened. If we strict believe Greening the energy required to detach each floor from the building is 0.63GJ, a global collapse could be stopped (even if you pull the building which gives the block the most favourable initial speed) if the building was a little bit stronger.

NIST noted that the methods for simulating the effects of an aircraft crash when the twin towers were built were inferor to modern methods.

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Deleted post, because I just don't want to get involved in this thread...

Ah, the goggles they do nothing! Paragraph breaks are your friend Non Believer.

twinstead said:

People, is there a school that guys like this attend to learn these techniques? I'm beginning to think there is.

Click to expand...

What you see is simply the difference between CT thinking and critical thinking. CT thinking is not methodical, structured or organized, it is stream of consciousness rambling. Based on what they believe is common sense and not facts or evidence.

Non Believer said:

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

The real engineer who did the work on the WTC said slow moving 707.

You are not a pilot, the 600 mph you mention is at altitude, not at approach speeds. The terrorist were speeding. As you saw the building did withstand the impact long enough to get most out of the building. Wow, it did withstand an aircraft impact. Did you miss out on something. But all you need to make your CT world complete is to find some explosives or you beam weapon. Fact would be neat, good luck finding them.

So you are just a CT nut case grabbing the nearest dumb idea.

Forest - Trees

WTC 1 & 2 survived the impact(s).

Planes hit. Building stood. Then fires started. (instantly)


Empire State building? Steel frame. Masonry exterior. Built to fire code of the time.


Once more - the towers were designed to withstand jetliner crash.

Towers did withstand jetliner crash.

Non Believer said:

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

Leslie E. Robertson, , said: on being hit by a commercial jet -
" It appears that about 25,000 people safely exited the buildings, almost all
of them from below the impact floors; almost everyone above the impact floors perished, either from the impact and fire or from the subsequent collapse. The structures of the buildings were heroic in some ways but less so in others. The buildings survived the impact of the Boeing 767 aircraft, an impact very much greater than had been contemplated in our design (a slow-flying Boeing 707 lost in the fog and seeking a landing field). Therefore, the robustness of the towers was exemplary. At the same time, the fires raging in the inner reaches of the buildings undermined their strength. In time, the unimaginable happened . . . wounded by the impact of the aircraft and bleeding from the fires, both of the towers of the World Trade Center collapsed."

http://www.nae.edu/nae/bridgecom.nsf/weblinks/CGOZ-58NLCB?OpenDocument

Non Believer said:

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

You seem to be missing the fact that a 707 and a 767 are not the same thing. I don't see how it is so hard to understand the size difference of the two planes. Even if it was designed to withstand a 707 going 550+mph, you don't seem to grasp the concept of weight. Which is a difference of about 100 tons.

Bubbers said:

You seem to be missing the fact that a 707 and a 767 are not the same thing. I don't see how it is so hard to understand the size difference of the two planes. Even if it was designed to withstand a 707 going 550+mph, you don't seem to grasp the concept of weight. Which is a difference of about 100 tons.

Click to expand...

707 was heavier. It had 4 engines and had to carry more fuel because the engines were not as efficient. (had to carry more fuel to go places)

But the speed limit below 10,000 feet is 250 KIAS. The design the real designer said it was a slow moving aircraft. The CT guys dig up the top speed at 30,000 feet of 600 mph.

The CT guys make up stories about super steel structures do not fail in fires.

It would be neat if this guy starting the thread would just state his ideas clearly and stop beating around asking silly questions.

Non Believer said:

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

Well here's what Swirsky said.

The towers were designed to survive a hit by a plane, but the aircraft that struck the towers Tuesday were much bigger and carried more fuel than airliners in use when they were built. Skilling is dead so we don't have his current comments.

http://archives.cnn.com/2001/US/09/17/gen.wtc.rebuild/index.html

I don't really have a problem with believing that the architects and engineers designed the buildings to withstand a jet plane hitting them.

It is said that they designed the towers for a 707 hit, fine, doesn't matter.

They used assumptions, and maybe, just maybe those assumptions were wrong.

Would the towers have survived a 707 hitting them, maybe, but I doubt it. I think the architects and engineers were just plain wrong. They used assumptions WRT speed and fuel capacity that maybe weren't applicable in real life. I mean, what are the odds that a fully fueled jetlier would hit at full speed? It wouldn't be the first time that someone overstated their capability.

So what?

I mean really, so what? CTers love to point out that the buildings were designed to withstand this or that. Maybe they were just wrong when they designed it.

Speaking of dead, if we could loan the CTduhers some brains, maybe this kind of silliness would be dead. One can dream!

jujigatami said:

I don't really have a problem with believing that the architects and engineers designed the buildings to withstand a jet plane hitting them.

It is said that they designed the towers for a 707 hit, fine, doesn't matter.

They used assumptions, and maybe, just maybe those assumptions were wrong.

Would the towers have survived a 707 hitting them, maybe, but I doubt it. I think the architects and engineers were just plain wrong. They used assumptions WRT speed and fuel capacity that maybe weren't applicable in real life. I mean, what are the odds that a fully fueled jetlier would hit at full speed? It wouldn't be the first time that someone overstated their capability.

So what?

I mean really, so what? CTers love to point out that the buildings were designed to withstand this or that. Maybe they were just wrong when they designed it.

Click to expand...

Exactly the tact I was thinking of taking. I was going to tell them to watch the show on History Channel called "Engineering Disasters" where dispite what the engineers designed for the damn things failed anyway.

Strange they can make a whole series out of engineering failures without a consipiracy.

Non Believer said:

Interesting that none of you choose to discuss John Skilling. He of course was the chief engineer on the trade towers. Here are some of his quotes. In the wake of the WTC bombing, the Seattle Times interviews John Skilling who was one of the two structural engineers responsible for designing the Trade Center. Skilling recounts his people having carried out an analysis which found the twin towers could withstand the impact of a Boeing 707. He says, “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.” 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. Frank Demartini was the on site project manager for the WTC's, and an architect. So for those of you who claim he was not involved in the design process you are technically right, but considering his degree of involvement and his technical expertise it is absurd to discount his opinions out of hand. Here is a third expert opinion. The architects who designed the World Trade Center designed it to withstand the direct impact and fuel fire of a commercial airline crash. Aaron Swirsky, one of the architects of the WTC described the collapse as "incredible" and "unbelievable." . Also Robertson responds to questions just months before the attacks about whether the towers were designed to resist terrorist attacks, saying only that the towers were designed to withstand the impact of a 707. If he didn't believe that they would not have survived the resultant fire that would have been a good time to mention it. For those of you who compared the forces from 767s to those of the B-25 bomber your quite aways off from what were talking about. But perhaps I should have explained that Skillings group calculated for a fully loaded 707. Doctor Fungi claims that the calculation was based on a 707 with an air speed of 180 MPH. Clearly this is simply wrong. Skilling stated that the calculation was done with an assumed airspeed of 600 MPH. So in fact the calculation for force of impact for the 707 and 767 are virtually identical. If you want to delve further into the specifics that's fine. As for the fact that beyond the 1964 white paper there is no record of this work (according to the NIST investigation). how does that work in favor of the official story. In my opinion it casts doubt the other way since so many of the pertinent documents and evidence involved in 9-11 are missing. And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

Paragraph breaks are your friend.

Calculations on paper never quite work out exactly in real life. There are too many variable in a chaotic system like a crash to be 100% accurate.

The engineers were limited to what they had to work with.
The buildings did survive the impact. It was the damage they were not totalty correct on.

The type of fire retardant and the method they used to apply it did not behave they way they though it would. I'm pulling a Chris here to reference the documentary from the discovery channel. "Anatony of a collapse" I think it was called. You can find it on Youtube. ( and if it's not there, you can blame it on the actions of the conspiracy nuts to destroy evidence that would disprove thier theories.)
And from Robertson's testimony posted in this thread, it seems they did not expect the fire to be so bad.

Non Believer -

Of COURSE they were designed to withstand airliner crashes. Each tower was designed to withstand the simultaneous hits of four - if you can believe this - SPACE PLANES traveling at Mach 3.75 - impacting all four faces of the tower. Boom-boom-boom-boom! It was a very forward-thinking group in 1964.

But they neglected the most obvious defensive building strategy. Godzilla. Who'd have thought that a Cretaceous tyrannosaur - fire-breathing to boot - could have arisen to do this? Sheathed in an invisibility cloak? Ya can't shoot what ya can't see. And ya can't build against what ya cannot imagine.

Non Believer said:

“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.

Click to expand...

So, a Boeing 707 doesn't go 600 miles per hour. The cruising speed is 550 mph (with some tricked-out prototypes nudging 612 mph). (source) The max cruising speed of the DC-8 was 588 mph. (source). So, I do not believe that anybody back in 1964 modeled a crash of either of these planes at 600 mph, a speed that (absent a controlled dive) was faster than either of those planes could go.

The designers worried about a lost pilot looking for a landing strip in the fog. He would have been going a lot slower than faster than the absolute fastest his plane could possibly go.

It is impossible that the designers were worried about a purposeful terrorist attack. First of all, prior to September 11, 2001, nobody was worried about terrorists using airplanes to attack civilian targets. Second of all, back in 1964, the only enemy anybody in the US cared about was the Soviets. And those guys had nuclear bombs.

PerryLogan said:

Even if someone proved that the towers were designed to survive such an impact, this would disprove a conspiracy.

Conspirators trying to fool the world would not deliberately place a striking anomaly at the center of their plan. They would not want anything to draw undue attention to the event. So the idea would never have gotten past the planning stage.

Here's the scenario:
Conspirator 1: Let's make it look like airliners brought the towers down.
Conspirator 2 (viciously smacking Conspirator 1 upside the head): Don't be an idiot! People would wonder why the towers fell. They would research the matter, find out we staged an impossible event...and we'd be caught. We're trying to make it look real, not give the game away! AHHH! (Smacking stupid old Conspirator 1 upside the head a few more times.)

I realize the assertion has been debunked quite thoroughly in this thread. My point is that--even if we lay technical matters aside--the conspiracist scenario falls apart logically.

Click to expand...

Roger that, Perry.

It's like dressing up E. Howard Hunt as a bum, putting him in Dealey Plaza and blowing away JFK.

Like we wouldn't recognize him later and topple the whole plot? True conspirators would use - geez - probably BUMS to play the bums.

By the way yer site is a friggin' riot. Somebody pointed me to it during my pitched battles with the CTs on another forum (hostile) and I've been laffin' ever since. Keep it up!

Non Believer said:

.... And finally in regard to the 99.9 percent assent of the ASCE membership to the official story, could you please give details on how the ASCE polls its membership ?

Click to expand...

OK, so I exaggerated. Skeptics are not immune from throwing out an occasional fallcy. But since I can't find but 2 structural/civil engineers(David Zuniga and James Pegelow?) who dispute the official findings - I can only think that there arent many. It could very well be that 99.9 % of the worlds civil engineering community agrees with the official story. Curiously, neither of these two gentlemen above have written a single word on the collapses. Can you, non believer, give me some more structural engineers who dipsute the collpases, preferably ones who've contributed to a peer-reviewed paper. Here are mine:


(The following list is far from exhaustive)

http://web.mit.edu/civenv/wtc/

John E. Fernandez - Assistant Professor of Architecture - MIT
http://architecture.mit.edu/people/profiles/prfernan.html
Eduardo Kausel - Professor of Civil and Environmental Engineering - MIT
http://linc.mit.edu/index.pl?id=2330
Tomasz Wierzbicki - Professor Applied Mechanics - MIT
http://ctl.mit.edu/metadot/index.pl?id=249...ategory&op=show
Liang Xue - Graduate student Mechanical Engineering - MIT
Meg Hendry-Brogan - Graduate student Ocean Engineering - MIT
Ahmed F. Ghoniem - Professor of Mechanical Engineering - MIT
http://me.mit.edu/people/personal/ghoniem.htm
Oral Buyukozturk - Professor of Civil and Environmental Engineering - MIT
http://cee.mit.edu/index.pl?id=2288&isa=Category&op=show
Franz-Josef Ulm - Professor of Civil and Environmental Engineering - MIT
http://cee.mit.edu/index.pl?id=2381
Yossi Sheffi - Professor of Logistics and Engineering - MIT
http://web.mit.edu/sheffi/www/



http://www-math.mit.edu/~bazant/WTC/
http://www-math.mit.edu/~bazant/WTC/WTC-asce.pdf
http://www.pubs.asce.org/journals/edem.html

Editor:

Ross B. Corotis, Ph.D., P.E., S.E., NAE, University of Colorado, Boulder
corotis@colorado.edu

http://ceae.colorado.edu/new/faculty/peopl...ple.cgi?corotis

Editorial Board:

Younane Abousleiman, Ph.D., University of Oklahoma http://mpge.ou.edu/faculty_staff/faculty.html
Ching S. Chang, Ph.D., P.E., University of Massachusetts http://www.ecs.umass.edu/cee/faculty/chang.html
Joel P. Conte, Ph.D., P.E., University of California, San Diego
http://kudu.ucsd.edu/
Henri Gavin, Duke University
http://www.cee.duke.edu/faculty/gavin/index.php
Bojan B. Guzina, University of Minnesota
http://www.ce.umn.edu/people/faculty/guzina/
Christian Hellmich, Dr.Tech., Vienna University of Technology
http://whitepages.tuwien.ac.at/oid/998877.html
Lambros Katafygiotis, Ph.D., Hong Kong University of Science and Technology
http://lambros.ce.ust.hk/
Nik Katopodes, Ph.D., University of Michigan
http://www.engin.umich.edu/dept/cee/prospective/
Nicos Makris, University of Patras
http://www.civil.upatras.gr/Melidep_gr/depi_en.asp?profid=5
Robert J. Martinuzzi, P.E., University of Calgary
http://www.ucalgary.ca/pubs/calendar/2005/...ademicAlpha.htm
Arif Masud, Ph.D., University of Illinois, Chicago
http://www.uic.edu/depts/bioe/faculty/core_faculty_list.htm
Arvid Naess, Ph.D., Norwegian University of Science and Technology
http://www.bygg.ntnu.no/~arvidn/front.htm
Khaled W. Shahwan, Daimler Chrysler Corporation
http://www.pubs.asce.org/WWWdisplay.cgi?9800592
George Voyiadjis, Ph.D., EIT, Louisiana State University
http://www.cee.lsu.edu/facultyStaff/Voyiad...iadjis_Gbio.htm
Yunping Xi, Ph.D., University of Colorado
http://ceae.colorado.edu/new/faculty/people/people.cgi?xi

Engineering Mechanics Division Executive Committee

Alexander D. Cheng, Ph.D., M.ASCE, Chair
http://home.olemiss.edu/~acheng/
James L. Beck, Ph.D., M.ASCE
http://www.its.caltech.edu/~jimbeck/
Roger G. Ghanem, Ph.D., M.ASCE
http://ame-www.usc.edu/personnel/ghanem/index.shtml
Wilfred D. Iwan, M.ASCE
http://www.eas.caltech.edu/fac_i-m.html#i
Chiang C. Mei, M.ASCE
http://cee.mit.edu/index.pl?id=2354&isa=Category&op=show
Verna L. Jameson, ASCE Staff Contact Journal of Engineering Mechanics



Bazant, Z.P., & Zhou, Y.
"Addendum to 'Why Did the World Trade Center Collapse? - Simple Analysis" (pdf)
Journal of Engineering Mechanics v. 128, no. 3, (2002): 369-370.

Brannigan, F.L.
"WTC: Lightweight Steel and High-Rise Buildings"
Fire Engineering v.155, no. 4, (2002): 145-150.

Clifton, Charles G.
Elaboration on Aspects of the Postulated Collapse of the World Trade Centre Twin Towers
HERA: Innovation in Metals. 2001. 13 December 2001.

"Construction and Collapse Factors"
Fire Engineering v.155, no. 10, (2002): 106-108.

Corbett, G.P.
"Learning and Applying the Lessons of the WTC Disaster"
Fire Engineering v.155, no. 10, (2002.): 133-135.

"Dissecting the Collapses"
Civil Engineering ASCE v. 72, no. 5, (2002): 36-46.

Eagar, T.W., & Musso, C.
"Why Did the World Trade Center Collapse? Science, Engineering, and Speculation"
JOM v. 53, no. 12, (2001): 8-12.

Federal Emergency Management Agency, Therese McAllister, report editor.
World Trade Center Building Performance Study: Data Collection, Preliminary Observations, and Recommendations
(also available on-line)

Gabrielson, T.B., Poese, M.E., & Atchley, A.A.
"Acoustic and Vibration Background Noise in the Collapsed Structure of the World Trade Center"
The Journal of Acoustical Society of America v. 113, no. 1, (2003): 45-48.

"Collapse Lessons"
Fire Engineering v. 155, no. 10, (2002): 97-103

Marechaux, T.G.
"TMS Hot Topic Symposium Examines WTC Collapse and Building Engineering"
JOM, v. 54, no. 4, (2002): 13-17.

Monahan, B.
"World Trade Center Collapse-Civil Engineering Considerations"
Practice Periodical on Structural Design and Construction v. 7, no. 3, (2002): 134-135.

Newland, D.E., & Cebon, D.
"Could the World Trade Center Have Been Modified to Prevent Its Collapse?"
Journal of Engineering Mechanics v. 128, no. 7, (2002):795-800.

National Instititue of Stamdards and Technology: Congressional and Legislative Affairs
“Learning from 9/11: Understanding the Collapse of the World Trade Center”
Statement of Dr. Arden L. Bement, Jr., before Committee of Science House of Representatives, United States Congress on March 6, 2002.

Pinsker, Lisa, M.
"Applying Geology at the World Trade Center Site"
Geotimes v. 46, no. 11, (2001).
The print copy has 3-D images.

Public Broadcasting Station (PBS)
Why the Towers Fell: A Companion Website to the Television Documentary.
NOVA (Science Programming On Air and Online)

Post, N.M.
"No Code Changes Recommended in World Trade Center Report"
ENR v. 248, no. 14, (2002): 14.

Post, N.M.
"Study Absolves Twin Tower Trusses, Fireproofing"
ENR v. 249, no. 19, (2002): 12-14.

The University of Sydney, Department of Civil Engineering
World Trade Center - Some Engineering Aspects
A resource site.

"WTC Engineers Credit Design in Saving Thousands of Lives"
ENR v. 247, no. 16, (2001): 12.