Questions - 7 World Trade Center
From Debunk911myths
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Questions about WTC7
Controlled demolition?
Claim
Controlled demolition was used to bring about the collapse of 7 World Trade Center on the afternoon of September 11, 2001.
Vincent Dunn, a retired deputy FDNY fire chief and author of the textbook, The Collapse of Burning Buildings, spoke with Popular Mechanics and explained the how the unique design of 7 World Trade Center, which was built on top of a Con Ed substation, made it extra vulnerable to the stresses imposed by the falling debris and fires on 9/11.
- "Instead of the vertical beams terminating in the foundation, many of them terminate in these broad, horizontal trusses that span the width of the building. Because the building was basically hollow from the sixth floor down. It was built over this big Con Ed substation. So those trusses carry these enormous loads far, far higher than we would see in a typical skyscraper. The combination of the falling debris - which greatly stressed the structure - raised the strain on these trusses. And then these fires that were fed in one case by a pressurized diesel fuel line, that raged for seven hours - and the current thinking of the engineers who investigated is more than enough to explain the collapse of the building. And in fact when those trusses failed, what you would've seen was exactly what we did see, which is the building almost collapsing from the inside first."[1]
Pull it
Claim
This claim was bolstered by a comment made by Larry Silverstein on a PBS documentary, America Rebuilds, where he uttered the phrase "pull it". Conspiracy theorists claim that this is slang term used in building implosions, and that with those words, Silverstein was authorizing the demoltion of WTC 7.
Fact
Controlled demolition experts reject the notion that "pull it" is a term used in building implosions.
The only context that "pull" has been used in building demolition is for small buildings (a few stories tall), where construction crews attach long cables to pre-weaken a structure and literally pull it down with bulldozers and other equipment.
"Pull" is also used by firefighters in reference to "pulling firefighters out of a building", because the situation is too dangerous. It is in this context that Silverstein used the term "pull it".
His spokesperson, Dara McQuillan, said that by "it", Silverstein was referring to the contigent of firefighters in WTC 7.
Firefighters
FDNY interviews available on the New York Times website also shed light on the use of "pull" in firefighting on 9/11, and help address the question of whether firefighters were in WTC 7 in the afternoon.
FDNY Captain Ray Goldback:
- "I'm going to guess it was after 3:00...we walked all the way back down to Vesey Street. There was a big discussion going on at that point about pulling all of our units out of 7 World Trade Center. Chief Nigro didn't feel it was worth taking the slightest chance of somebody else getting injured. So at that point we made a decision to take all of our units out of 7 World Trade Center because there was a potential for collapse." [1]
Firefighter Richard Banaciski was in the Verizon Building, adjacent to WTC7.
- "Finally they pulled us out. They said all right, get out of that building because that 7, they were really worried about. They pulled us out of there and then they regrouped everybody on Vesey Street." [2]
Deputy Chief Peter Hayden:
- "By now, this is going on into the afternoon, and we were concerned about additional collapse, not only of the Marriott, because there was a good portion of the Marriott still standing, but also we were pretty sure that 7 World Trade Center would collapse. Early on, we saw a bulge in the southwest corner between floors 10 and 13, and we had put a transit on that and we were pretty sure she was going to collapse. You actually could see there was a visible bulge, it ran up about three floors. It came down about 5 o'clock in the afternoon, but by about 2 o'clock in the afternoon we realized this thing was going to collapse."
- "Firehouse: Was there heavy fire in there right away?"
- "Hayden: No, not right away, and that's probably why it stood for so long because it took a while for that fire to develop. It was a heavy body of fire in there and then we didn't make any attempt to fight it. That was just one of those wars we were just going to lose. We were concerned about the collapse of a 47-story building there. We were worried about additional collapse there of what was remaining standing of the towers and the Marriott, so we started pulling the people back after a couple of hours of surface removal and searches along the surface of the debris. We started to pull guys back because we were concerned for their safety." [3]
Command and control
The most important operational decision to be made that afternoon was the collapse had damaged 7 World Trade Center, which is about a 50 story building, at Vesey between West Broadway and Washington Street. It had very heavy fire on many floors and I ordered the evacuation of an area sufficient around to protect our members, so we had to give up some rescue operations that were going on at the time and back the people away far enough so that if 7 World Trade did collapse, we wouldn't lose any more people. — Chief Daniel Nigro [4]
Free fall?
Fact
The collapse did not occur at free fall speed. It took 16 seconds, with the east mechanical penthouse beginning to collapse 8.2 seconds before any more obvious signs of total collapse (as seen on videos).
- How fast did WTC7 fall - video
For comparison to see what an actual controlled demolition is like, here is a video of one that took place in June 2006, with the demolition of the Tencza apartments in Arlington, Virginia - See video
BBC reported collapse of WTC7 early
Fact
- Part of the conspiracy? - BBC
- Part of the conspiracy? (2) - BBC
No steel was recovered from WTC7
Fact
Members of the FEMA/ASCE Building Performance Study Team and others including members of the Structural Engineers Association of New York (SEAoNY), Dr. J. Gross, a structural engineer at NIST, and Professor A. Astaneh-Asl of the University of California, Berkeley had access to the recovery yards where debris, including the steel, was taken during the cleanup effort.
There were four major sites where debris from the WTC buildings was shipped during the clean-up effort and these teams looked for debris were:
- Hugo Neu Schnitzer, Inc., Fresh Kills Landfill in Staten Island, New Jersey;
- Hugo Neu Schnitzer East, Inc., Claremont Terminal in Jersey City, New Jersey;
- Metal Management, Inc., in Newark, New Jersey; and
- Blanford and Co. in Keasbey, New Jersey.
Specific pieces of debris they were searching for included badly burned pieces from WTC 7, and connections from WTC 1, 2, and 7 (e.g., seat connections, single-shear plates, and column splices). They were unable to unambiguously identified any pieces as being from WTC 7.
Structural steel elements were also collected and held by the Port Authority of New York and New Jersey (PANYNJ) in Hanger 17 located at John F. Kennedy (JFK) International Airport. The main goal of the PANYNJ project was to decontaminate and preserve the steel, as well as other WTC artifacts, for future exhibits and memorials.
At Fresh Kills and the other sites, they were unable to identify with 100% certainty any pieces as being from WTC 7, and not from the twin towers. But, they had the opportunity to look and did collect samples for the twin towers. With any pieces found from WTC 7, NIST also needed to to know where in the structure the piece was located. Pieces from the twin towers were marked with identification codes to help determine the location, but that may not have been the case in WTC7.
Dr. Astaneh-Asl, a structural engineer from U.C. Berkeley who was on-site after 9/11 to examine steel, saw a charred horizontal I-beam from 7 World Trade Center, a 47-story skyscraper that collapsed from fire eight hours after the attacks. The beam, so named because its cross-section looks like a capital I, had clearly endured searing temperatures. Parts of the flat top of the I, once five-eighths of an inch thick, had vaporized. Less clear was whether the beam had been charred after the collapse, as it lay in the pile of burning rubble, or whether it had been engulfed in the fire that led to the building's collapse, which would provide a more telling clue. The answer lay in the beam's twisted shape. As weight pushed down, the center portion had buckled outward. "This tells me it buckled while it was attached to the column," not as it fell, Dr. Astaneh-Asl said, adding, "It had burned first, then buckled."[2]
A piece of A36 steel from WTC 7 was recovered and analyzed by J.R. Barnett, R.R. Biederman, and R.D. Sisson, Jr., though they could not determine the exact location of this beam. [5]
Although no steel was recovered from WTC7 to allow NIST to conduct tests on actual material from the structure, WTC 7 was constructed of three grades of conventional steel (36 ksi, 42 ksi, and 50 ksi). Literature values can be used to estimate properties of these standard types of steel.
NIST also worked from structural design drawings and standard practice for the mid 1980’s, interviewed building designers, and reviewed available photographs of building during renovations.
- Steel Inventory and Identification
- An Initial Microstructural Analysis of A36 Steel from WTC Building 7