I love my commenters. It let’s me know that people are reading. And that, among all things in life, is the greatest feeling in the world. I love it especially when commenters leave messages that attempt to disprove the 9/11 conspiracy theory. I’m not talking about those, “You’re a dumbass! what are you crazy of course 9/11 was terrorist! you hate america…” comments. I’m talking about the open-minded and respectful people who want to lean more and perhaps have a discussion. I got one yesterday,
Compare the collapse of WTC building 7 as shown in the video
http://www.nist.gov/public_affairs/releases/wtc_videos/wtc_videos.html
with the collapse as modeled by NIST in their own document
http://wtc.nist.gov/media/NIST_NCSTAR_1-9A_for_public_comment.pdf
page 108, figure 4-62.
In the video the exterior vertical walls, except for the start of a single vertical wrinkle, remain connected to and supported by the large number of perimeter columns and retain their rectangular shape until late in the collapse. In NIST’s theoretical model the exterior columns almost immediately buckle inwards over the building.
Watch the video. I mean it. Watch the video. It had me doubting there for a second. The bomb statistic had me the most. But then I stopped, and read the link: NIST.gov. The National Institute of Standards and Technology is a government agency. At first I thought they were independent. Perhaps I was fooled by the opening lines. The narrator admits that no steel framed-building in history has fallen due to fire, which made me think automatically, that they were on our side. It was a tricky tactic, I’ll give them props on that one.
I watched the video several times, and the facts presented are inconsistent with anything even close to being somewhat fact. They contradict history. They tell us that some new way of building collapse occurred. I’m sorry to say, physics doesn’t just invent new ways of building collapse. Steel framed buildings all fall the same way when presented with fire: they don’t. The variable is unchanging.They tell us that the bombs would have been louder if it had been controlled demolition. Lots of bombs, especially in controlled demolition, are not that loud. I can’t hear them when witnessing a controlled demolition, and I can’t hear them on videos.
The point is, don’t believe everything you hear. Back up your information and research what you read.
3 responses so far ↓
Arthur Scheuerman // September 20, 2008 at 8:48 am
The exterior walls were removed in the display so that we can see the interior floors and columns. The outside walls were the last to fall buckling on the lower floors out of sight of the cameras.
Philippok // September 21, 2008 at 12:44 am
Please explain “The outside walls were the last to fall.” Aren’t the walls fastened to the exterior columns? How can the walls stand without the exterior columns?
Arthur Scheuerman // September 28, 2008 at 4:14 pm
The outside walls included the exterior columns.
You may say it’s highly unreasonable to believe that 4 steel constructed high-rise buildings collapsed from fire in one day? Well they all had one thing in common. Long Span steel composite floors. Long span steel beams have a magnified response to heat. They expand a longer distance than short span beams and they still have their full strength in the beginning of the expansion. NIST computer studies show that this strength while elongating can shear off the bolts connecting the beams to the columns or girders as the restrained beams expand. This strength can also crack the concrete slab at the shear studs and buckle the beam itself as the compression builds up during expansion.
A buckled or bowing (bowing occurs when the bottom flange of a steel beam expands faster than the top flange) long span (typically 40 to 50 feet) beam can impart large tension forces on the connections especially when the deflected beam begins to shrink as it cools. The fireproofing insulation thickness schedules in the Building Code were developed for the short span floors which were used in the older buildings and this insulation defended against weakness in the steel beams which occurs at higher temperatures 1100deg. F (about 600 deg. C). Low temperature expansion effects occur at temperatures below 400 deg. C and have not yet been compensated for in the codes. This deficiency in long span, high-rise office buildings is a new discovery discovered by the study of the collapse of the Twin Towers and Buildings 5 and 7 and was first illuminated by engineering computer studies. WTC 7 met all New York City codes and was not hit by any planes and was destroyed by a fire in ordinary combustible furnishings.
Another important characteristic of large open areas with combustible furnishings is that a fire can spread over the whole area and release a large quantity of heat if not extinguished immediately as by a working water spray system (sprinkler). The water spray systems in both towers were damaged by the forces of plane impacts and in Building 7 the water spray and standpipe water supply were cut off by the tower’s collapse impacts damaging the water mains in the streets.
The other thing about long span floors is that the builders relocate or remove the interior columns to get the open office areas that they wanted in the first place. When a column or columns fail under such large open area circumstances it or they may not be able to redistribute the floor loads to other columns and the collapse is likely to progress upwards. If the building is not protected against progressive collapse, global (total) collapse can ensue. Building 7 collapsed because one key interior column failed after the long span floors failed around it
Arthur Scheuerman
Ret. Battalion Chief, FDNY