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Aaron Swirski, architect, says WTC floors designed to self-seal in case of emergency.
Jeruselem Post Radio ^ | 9-11-2001 | Aaron Swirski

Posted on 09/11/2001 8:12:00 PM PDT by SlickWillard

Swirski: "each floor... by itself... is designed to be a hermetically sealed unit..."

Swirski: "it's not 50,000, it's half a million people who work in those buildings"

Swirski: "that building doesn't even have sprinklers."

Swirski: "shut off ... vertical openings"

Q: "Does that also mean that people couldn't travel from one floor to another?"

"That's right. No, they couldn't"


TOPICS: Culture/Society; News/Current Events
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Interview Here.

Previous Thread Here.

1 posted on 09/11/2001 8:12:00 PM PDT by SlickWillard
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To: SlickWillard
http://www.chicagotribune.com/news/nationworld/chi-010911kamin-towers.story

From the Chicago Tribune

Skyline symbols of economic might

Engineers shocked by towers’ collapse

By Blair Kamin
Tribune architecture critic

September 11, 2001, 12:18 PM CDT

The World Trade Center, a symbol of American economic might, survived one terrorist attack in 1993. It was designed to withstand the impact of a jet, but both its towers collapsed this morning after planes rammed them.

The structural engineer who designed the towers said as recently as last week that their steel columns could remain standing if they were hit by a 707.

Les Robertson, the Trade Center’s structural engineer, spoke last week at a conference on tall buildings in Frankfurt, Germany. He was asked during a question-and-answer session what he had done to protect the twin towers from terrorist attacks, according to Joseph Burns, a principal at the Chicago firm of Thornton-Thomasetti Engineers.

Burns, who was present, said that Robertson said of the center, “I designed it for a 707 to smash into it.”

Burns, whose firm did the structural engineering for the Petronas Twin Towers in Malaysia -- the world’s tallest buildings -- said Robertson did not elaborate on the remark. Robertson could not be reached early today.

Completed in 1972 and 1973, the 110-story twin towers were the fifth and sixth tallest buildings in the world. One World Trade Center, finished in 1972, was briefly after its construction the world’s tallest building. The towers have been called “a monumental gate to New York and the United States.”

They withstood the 1993 attack, when a bomb-laden van exploded, killing six people and injuring more than 1,000.

Closely spaced steel columns that ringed their perimeter held up the World Trade Center towers. Chicago’s Aon Center (formerly the Amoco Building), completed in 1973, uses a similar support system, known to structural engineers as a “tube.”

Shocked by the building’s collapse, structural engineers pointed to fire as the likely cause of the structural failure.

“Fire melts steel,” Burns said. In addition, he said, the impact of the plane could have severely damaged the building’s sprinklers, allowing the fire to rage, despite fireproofing supposed to protect steel columns and beams.

“You never know in an explosion like that whether they (the sprinklers) get cut off,” Burns said.

Architects Minoru Yamasaki and Associates, in association with Emery Roth & Sons, designed the World Trade Center.

The structural engineers were the firm of Skilling, Helle, Chrstiansen, Robertson. The developer was The Port Authority of New York and New Jersey.

Today’s attack marked the second time that a plane has crashed into a New York City skyscraper, although the first incident was an accident.

In 1945, a B-25 flying at 200 miles per hour slammed into the 78th and 79th floors of the Empire State Building, gouging an 18-by-20-foot hole 913 feet above the streets of Manhattan. The pilot, Lt. Col. William F. Smith Jr., had been heading from New York’s LaGuardia Airport to Newark, N.J., when he became disoriented.

Fourteen people died in the crash and the fire that followed -- three people in the plane and 11 in what was then the world’s tallest building.

Like the World Trade Center, the Pentagon, which also was struck by a plane, provided a sizable and symbolic target.

The Pentagon is the world’s largest office building, with a total of 6.5 million square feet, serves as headquarters for the world’s most powerful military. Sears Tower, by comparison, has about 3.5 million square feet of office space.

Copyright © 2001, Chicago Tribune

2 posted on 09/11/2001 8:15:39 PM PDT by SlickWillard
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To: SlickWillard
Lets see....half a million people huh?

That comes to 500,000 divided by 220 floors (110 stories each tower).

Thats 2300 people per floor? Nope...dont think so, not even when you count the ancillary buildings, such as the 47 story Tower 7 etc.

3 posted on 09/11/2001 8:20:05 PM PDT by keithtoo
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To: keithtoo
I've seen figures of 150,000 in the WTC complex on a given day. Another figure: More than 50,000 work there, 70,000 visit.
4 posted on 09/11/2001 8:22:10 PM PDT by bvw
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To: SlickWillard
The Jerusalem Post

WTC architect: Collapse 'unbelievable'


By Michal Meyer and Stuart Winer September, 12 2001

JERUSALEM (September 12) - Aaron Swirsky, one of the architects of the World Trade Center, yesterday expressed disbelief on hearing of the collapse of the twin towers. Swirsky told JPostRadio the buildings had been designed with "accidents" in mind.

"The terrorism was different in those days, but there was always the possibility of an accident with a plane hitting the building. The building was designed like a pipe structurally, with the main structure in the perimeter of the building." This meant that a hole in the building would not collapse the whole structure. The fact that the buildings did collapse he described as "incredible."

Swirsky said the 1993 bombing of the World Trade Center made a big hole in one building. "The intent was to topple the building, but because of the design it didn't. But now... it is unbelievable." He said the collapse may have been due to the size of the plane, bigger than the architects had ever planned for.

The floors above the crash sites would have been safe, at least at first, said Twirsky. "What is really tragic is the building was designed with each floor as a hermetic unit, as to evacuate a building like that is a nightmare. Imagine you are on the 100th floor and there is no elevator, so each floor is designed to be safe; but when it collapses then that whole theory goes up in smoke."

The buildings had no sprinklers, because each floor could be sealed off from the others in case of a fire. "There are shutters that would shut off the vertical openings [between floors] so that the fire couldn't travel from one floor to the other. That was the theory. When the danger had subsided they could evacuate."

After the planes crashed into the buildings, Swirsky said people in the floors above would have been trapped. They would have been unable to escape. The buildings were not designed to allow for a quick exit in case of emergency. Afterward, those trapped would have fallen with the buildings when they collapsed.

5 posted on 09/11/2001 8:22:31 PM PDT by SlickWillard
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To: SlickWillard
It will be interesting to see how many companies go bankrupt out of this. I wonder what the insurance policy on the buildings was.
6 posted on 09/11/2001 8:22:35 PM PDT by lawgirl
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To: keithtoo
Thats 2300 people per floor?

On the other hand, if you think about 24 hour a day operations, you get three shifts of eight hours, and that would alter your figure to about 800 per floor. Also: there may have been lots of part-time workers who may or may not have been there this morning.

7 posted on 09/11/2001 8:25:31 PM PDT by SlickWillard
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To: lawgirl
Insurance doesn't cover acts of war.
8 posted on 09/11/2001 8:26:35 PM PDT by reformedliberal
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To: SlickWillard
The buildings had no sprinklers, because each floor could be sealed off from the others in case of a fire. "There are shutters that would shut off the vertical openings [between floors] so that the fire couldn't travel from one floor to the other. That was the theory. When the danger had subsided they could evacuate."

If this is true, there could be tens of thousands dead.

9 posted on 09/11/2001 8:29:17 PM PDT by SlickWillard
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To: SlickWillard
Insurance almost never covers an act of war. that it what they will claim (esp. if we declare war on osama). check the fine print on your life, home, etc. insurance policy.
10 posted on 09/11/2001 8:30:00 PM PDT by salbam
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To: lawgirl
perhaps we could extract some 'reparations' in the form of oil.
11 posted on 09/11/2001 8:36:31 PM PDT by phothus
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To: SlickWillard
WHERE ARE THE TRIAL LAWYERS WHEN WE NEED THEM ?????

CALLING NC SENATOR EDWARDS !!!!!

HAVE YOU BEEN TRAUMATIZED BY TODAY'S EVENTS ???? THIS WAS THE WORK OF NEGLIGENT ENGINEERS & ARCHITECTS, NOT OSAMA !!!!!

CALL DEWEY, CHEATEM & HOWE ... TRIAL LAWYERS FOR THE NEW MILLENIUM. DC&H WILL GET YOU SOME BIG BUCKS -- THOUGH WE'LL KEEP EVEN MORE.

12 posted on 09/11/2001 8:39:59 PM PDT by dodger
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Comment #13 Removed by Moderator

To: Northman
but the explosive force of the jet fuel was something the designers probably didn't account for

I imagine that the heat of the jet-fuel-fueled fire caused the steel skeleton to melt.

14 posted on 09/11/2001 8:43:21 PM PDT by SlickWillard
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To: SlickWillard
No sprinklers? Don't think so. I worked at 2 WTC, 89th floor, in 1984 and 1985 (Ebasco, now owned by Raytheon).
15 posted on 09/11/2001 8:44:58 PM PDT by Fred Hayek
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To: SlickWillard
Shocked by the building’s collapse, structural engineers pointed to fire as the likely cause of the structural failure.

“Fire melts steel,” Burns said. In addition, he said, the impact of the plane could have severely damaged the building’s sprinklers, allowing the fire to rage, despite fireproofing supposed to protect steel columns and beams.

The sprinkler system was not designed to handle a fire load of several hundred gallons of jet fuel on multiple floors of the building. It was only a matter of time before the heat of the fire weakened enough of the structural steel that was left after the inital impact. No amount of "fireproofing" can protect the structural support for an extended fire. The temperatures inside the structure were likely well above 1200 F. With that much heat and as much damage as the impact did, it is amazing that the building lasted as long as it did.

16 posted on 09/11/2001 8:52:50 PM PDT by eggman
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To: Fred Hayek
No sprinklers?

Yeah, I was a little troubled by this assertion, and by the figure of half a million people. I hope the Jerusalem Post didn't have their chain yanked by some con man posing as a retired architect. I posted the story because of the assertion that the floors were designed to self-seal. If this is true, then it is possible that tens of thousands of people were sealed in one great big coffin, with no hope of emerging.

I saw an interview with a survivor who said that the fire doors were locked (which would be consistent with the self-sealing assertion), and that they had to break the window of a Barnes and Noble bookshop in the lobby, go through the bookshop, down an escalator, through the basement, and back up another escalator before they could find an exit to the street.

17 posted on 09/11/2001 8:55:14 PM PDT by SlickWillard
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To: SlickWillard
A friend of mine that designs buildings said that the weight of the HVAC/communications gear on the top floors plus the impact and fire basically made the weight above the plane hits more extreme. When the superstructure failed. And when the top floors came down it was like a hammer hit the top of the building. He also compared it to watching a black belt in karate chop several boards. Not sure what he meant by that.
18 posted on 09/11/2001 9:01:51 PM PDT by isthisnickcool
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To: SlickWillard
The structural engineer who designed the towers said as recently as last week that their steel columns could remain standing if they were hit by a 707.

Les Robertson, the Trade Center’s structural engineer, spoke last week at a conference on tall buildings in Frankfurt, Germany. He was asked during a question-and-answer session what he had done to protect the twin towers from terrorist attacks, according to Joseph Burns, a principal at the Chicago firm of Thornton-Thomasetti Engineers.

Burns, who was present, said that Robertson said of the center, “I designed it for a 707 to smash into it.”

Was this part of the planning process? Who was it that asked that question? Were they possibly "testing" their plans? Finding out what size plane they had to have?

19 posted on 09/11/2001 9:05:19 PM PDT by charphar
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To: SlickWillard
My son works as a architect a few blocks from the trade center. He says that engineering codes require that the steel structure must withstand an hour of fire -- which they did.

Many people escaped. The stairs were not blocked. I saw video of people descending the stairs. there were working lights in the stairwells this time.

It will be a while before we know the death toll, but it appears that those who began evacuation immediately had a good chance -- except for those above the fire.

20 posted on 09/11/2001 9:11:58 PM PDT by js1138
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