How the FDNY (and others) may have predicted collapse of WTC7

This was being discussed in the BBC video thread but I thought it merited its own. People have pointed out a few quotes that mention the equipment they were using to analyse the stability of the buildings on 911, and may explain how they managed to predict the collapse of WTC7. I know there are a lot of issues relating to WTC7 and the demolition theory, hopefully this thread can be used to discuss the viability of predicting a collapse using the methods stated. This is relevant to the current buzz about the 'precog' videos as if they had accurately and scientifically predicted a collapse then it is a much smaller step for a few news agencies to hear chinese whispers that it had already happened.

1)
Quote from Deputy Fire Chief Peter Hayden

This quote would suggest that with the use of a surveyor's transit (also called a theodolite) the FDNY predicted the collapse of WTC7 by 14:00, over three hours in advance of the collapse.

"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.

...we had to pull everybody back. It was very difficult. We had to be very forceful in getting the guys out. They didn't want to come out. There were guys going into areas that I wasn't even really comfortable with, because of the possibility of secondary collapses. We didn't know how stable any of this area was. We pulled everybody back probably by 3 or 3:30 in the afternoon. We said, this building is going to come down, get back. It came down about 5 o'clock or so, but we had everybody backed away by then."

Do the FDNY still have the data from this equipment? Is it possible to obtain this data, possibly by the FOIA? Why isn't it in the NIST report? Just a few questions raised by that one. There is also the contradiction that they knew by 14:00 that it would fall however he follows by stating that they didn't know how stable the area was. That might reflect the inaccuracy of the method.


[edit on 28-2-2007 by Giordano Bruno]

2) Army tools used for search and rescue at World Trade Centre could pay off in future

Cecom didn't arrive till the 13th, so they cant have been monitoring WTC7 on the day, however it discusses some of the technology available for assessing structural stability. Other agencies there at the time may have possessed similar equipment so I've included it for that reason. I'd also be interested to know who the 'local construction survey company' were and what data they collected:

A local construction survey company was managing "transits" to measure the building's movements. Transits are used to measure grade and elevation electronically. They were fixed on a point on the side of the building and checked about every five minutes to see if the building had moved, Lacko said. But the transits could give inaccurate readings because they were unable to filter out vibrations from heavy machinery or other factors in the area.

The readings caused numerous false alarms that required areas to be evacuated for hours at a time. "The search and rescue folks were on for 20 minutes and then off for two to three hours," Albarelli said.

Lacko's team used laser Doppler vibrometers, which send out laser signals that hit pieces of reflective tape and then beam signals back that help workers determine the vibrational frequency of the structure, he said. The tool sits on a tripod and is about 5 inches tall and 12 inches long.

"The laser Doppler vibrometer measures a building's frequency and whether it's vibrating five times a second, or if it moved six micrometers or six centimeters," Lacko said. "It determineshow much it's actually moving and at what frequency."

Rescuers were able to home in on the building's frequency because it was different from the ones created by heavy machinery and jackhammers, he said.

The laser Doppler vibrometer was set up about 20 feet from the transit station — where the air horn used to alert personnel of a work stoppage was also kept — and the two tools were used together to help eliminate false alarms. "It gave all the workers in and around that point better security at the time as to whether that building was going to come down," Lacko said. "There was more technology on site to determine if the building was stable. Several different workers thanked us for coming."

From this report it looks like until Cecom turned up only the transits were being used. How inaccurate were the readings? Accurate enough to predict WTC7 collapse?

Any other links to sites pertaining to measurements taken on the day, organisation doing the work, or technical advice regarding the use and application of the instruments would be most helpful to this discussion


[edit on 28-2-2007 by Giordano Bruno]

www.firehouse.com...


Firehouse Magazine Reports
The Two Towers: A Challenge To Two Professions

JOHN P. FLYNN, PE
From the April 2002 Firehouse Magazine

>>"Heavy, thick smoke rises near 7 World Trade Center. Smoke is visible from the upper floors of the 47-story building. Firefighters using transits to determine whether there was any movement in the structure were surprised to discover that is was moving. The area was evacuated and the building collapsed later in the afternoon of Sept. 11.

Originally posted by Giordano Bruno

A local construction survey company was managing "transits" to measure the building's movements. Transits are used to measure grade and elevation electronically. They were fixed on a point on the side of the building and checked about every five minutes to see if the building had moved, Lacko said. But the transits could give inaccurate readings because they were unable to filter out vibrations from heavy machinery or other factors in the area.

Those machines were looking for VIBRATIONS, and what else does it say?

The readings caused numerous false alarms that required areas to be evacuated for hours at a time.

FEMA also picked up numerous seismic events after the collapses of the Twin Towers, but before the collapse of WTC7.

These unexplained seismic events provide an explanation for the numerous vibrational false alarms, as reported.


Now the question: What caused those vibrations, and seismic events, to cause false alarms?

[edit on 28-2-2007 by bsbray11]

If you're suggesting that the seismic events were preplanted explosives used to bring down the towers, then they wouldn't have been false alarms, they would have coincided with the collapses and whoever was taking the measurement would probably have analysed the readings with that pre-concluded i.e. 'this big event on the chart was due to collapse of WTC1' etc.

If it can pick up heavy machinery vibrations then we're probably talking about errors caused by factors of a lesser megnitude than huge explosions.

Originally posted by Giordano Bruno
If you're suggesting that the seismic events were preplanted explosives used to bring down the towers, then they wouldn't have been false alarms, they would have coincided with the collapses

Ah, but you don't know that, and I seriously doubt you are qualified to speculate here with much accuracy.

I know this though, and you can look up clips of demolitions and prove this yourself: explosive charges aren't always just let off in one linear wave up or down the building and that's it. Structures have to be tailored to, to be able to have the most control possible over how they will fall. To conceal all but the final wave (more at least make it much less obvious), you space out the detonations over a much larger span of time. That hard to imagine such a scenario?

If their collected data provides evidence of explosives that would be a good reason to get hold of it.

However my key question is this.

Disregarding whether or not the towers were demolished or collapsed due to two plane impacts plus aftermath, is it possible to predict accurately when a building will collapse due to structural weakness with the instruments/expertise present that day. That would be the only way I could see the collapse message getting out early. Especially so close to the time. Otherwise there would have been a general evacuation of the area and noone would have known what was going to fall. (Unless it didn't 'fall')

Sorry but a little fire in a part of a building doesn't make it fall at free fall speed, nor in his own footprint, Silverstein saying pull it, accounts of police officers heard explosions, people in the basement of WTC7 who saw explosives going off before escaping... And the girl just red the teleprompter, and the script was that WTC7 was going to collapse, why? Because there was EXPLOSIVES IN IT.

THIS WAS CONTROL DEMOLITION PERIOD.

[edit on 1-3-2007 by Vitchilo]

Originally posted by Vitchilo
Sorry but a little fire in a part of a building doesn't make it fall at free fall speed, nor in his own footprint, Silverstein saying pull it, accounts of police officers heard explosions, people in the basement of WTC7 who saw explosives going off before escaping... And the girl just red the teleprompter, and the script was that WTC7 was going to collapse, why? Because there was EXPLOSIVES IN IT.

THIS WAS CONTROL DEMOLITION PERIOD.

Congrats!..You have effectively closed your mind on the matter, and your programming is complete.

[edit on 1-3-2007 by GwionX]

MORE than 375 tons of steel - requiring 12 miles of welding - will be installed to reinforce floors for Salomon's extra equipment. Sections of the existing stone facade and steel bracing will be temporarily removed so that workers using a roof crane can hoist nine diesel generators onto the tower's fifth floor, where they will become the core of a back-up power station.

They might have made a bit of a bang. And there was fires around there.

Also, when people keep saying wtc7 collapsed from a fire, its not entirely true, and makes your argument easy to dismiss. People just say 'And there was a llarge gash in the SW side'. the question is whether this plus fires could bring the building down.

I agree that it seems unlikely given the rapid nature of the collapse, and NIST's 'domino column' theory, but as I'm no demolition/building collapse expert I would be premature to rule out the possibility that one corner gouged off at the base plus fires near a diesel power station caused a predictable collapse, and that the damage was sufficient for rapid global collapse, with no vertical supports remaining. The collapse was predicted by scientific equipment which was being used that day in that area. And that was the source of the emergency workers in the area, the media etc. knowing about the imminent collapse. Any explosive sounds were from the diesel generators.

...which seems a stretch...

...but at least it would mean that random things can happen and not that we're living in the twilight zone...

Originally posted by GwionX
Congrats!..You have effectively closed your mind on the matter, and your programming is complete.

Or thought for himself, but apparently you can't tell the difference.

Do you know what friction is? You never answered me when I asked what your educational background is, so I just thought I'd ask.