It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Originally posted by AHCivilE
This fire alone would not have led to its collapse. The structural damage, however, did allow this fire to to weaken the steel (and heat it causing it to expand and cause greater stresses. to the point were it could no longer support the eccentricity provided by the missing columns. Axial loads are easy enough to support, but when one takes a column designed from concentric load (either tension or compression) and subjects it to extreme eccentricity from an unbalanced load (where two columns are missing next to secure set one would have twice the load and an eccentricity that would lead to a moment approximately equal to ((typical distributed load shared over that section)* 8*(spanlength)^2)/11. That is not exact because of the fashion they constructed it in but its a good approximation. Anyone who really wants a feel for how large steel buildings should sit down with the AISC codebook. I mostly work and concentrate on reinforced concrete and stay away from tall building and stick to bridges, but I can assure you that 99.99 percent of steel structures would fail under this kind of duress.
Originally posted by LeftBehind
Sorry fellas I never said anything about molten steel or steel glowing red.
But it is downright silly to compare an office fire covering acres of space to a burner on either a gas or electric stove.
The comparison has no value whatsoever, as the conditions do not match up at all.
To expect the properties of a burner on a stove to somehow make a point about gigantic office fires is one of the longest stretches imaginable, and to be frank, is laughable.
Originally posted by Nonchalant
Nothing pulverises concrete quite like a mini nuke..
Your scenario is laughable.
Originally posted by LeftBehind
Sorry fellas I never said anything about molten steel or steel glowing red.
But it is downright silly to compare an office fire covering acres of space to a burner on either a gas or electric stove.
The comparison has no value whatsoever, as the conditions do not match up at all.
To expect the properties of a burner on a stove to somehow make a point about gigantic office fires is one of the longest stretches imaginable, and to be frank, is laughable.
Are you really trying to get people to believe that an electric burner on an oven burns hotter than a multistory fire burning acres of office space?
Originally posted by pointman1921
Hmmm.. ok so a building that was not designed to withstand an impact of a jetliner gets hit. Jet fuel goes everywhere and ingnites, lighting everything (carpet, walls, floor tiles, pretty much everything) on fire. This occured a couple hundred feet up with fairly strong winds. I've been around fire a lot in my life and know from first hand experience that when you add any type of wind current to a fire with plenty of fuel you create a furnace type atmosphere.
Once this kind of heat hits a steel beam, it heats the steel beam up. Now if you tried to heat just a cross section of that beam, nothing would really happen. But seeing it's steel and conducts heat fairly well, a large portion of that beam becomes heated, weakened and slightly begins to bend. Now mutiply that by as many beams as were affected. . .
PS..... For those who think the floors below should have stood, take approximately 3/8 to 5/8 of what you think you could lift (approximately the what we design for in structures compared to standard load) and then have someone drop it from 8 feet up and let's see you catch it.
Originally posted by esdad71
That was a fantastic analogy.
The dynamic collapse of energy-absorbing structures is more difficult to understand than the corresponding quasi-static collapse, on account of two effects which may be described as the "strain-rate factor" and the "inertia factor" respectively. The first of these is a material property whereby the yield stress is raised, while the second can affect the collapse mode, etc. It has recently been discovered that structures whose load-deflection curve falls sharply after an initial "peak" are much more "velocity sensitive" than structures whose load-deflection curve is "flat-topped"; that is, when a given amount of energy is delivered by a moving mass, the final deflection depends more strongly on the impact velocity. In this paper we investigate strain-rate and inertia effects in these two types of structure by means of some simple experiments performed in a "drop hammer" testing machine, together with some simple analysis which enables us to give a satisfactory account of the experimental observations. The work is motivated partly by difficulties which occur in small-scale model testing of energy-absorbing structures, on account of the fact that the "strain-rate" and "inertia" factors not only scale differently in general, but also affect the two destinct types of structure differently.
Originally posted by Zaphod58
You mean your mini nuke that caused no radiation sickness, no massive increase in radiation, no EMP, and none of several other effects caused by a nuclear blast?
As for the tritiated water, there were many things in the towers that had small amounts of tritium in them that could have caused that effect.
Originally posted by amfirst
The 911 conspiracy is getting old...too many inconsitancy
Originally posted by Nonchalant
[Did anyone besides FEMA or any other govt agency take radiation readings from any of the sites?
[edit on 7-4-2007 by Nonchalant]
On Sept. 11, I called a medical doctor who lives 7 miles from the Pentagon and warned her that DU could have burned in the hijacked jets that crashed (up to 3000 pounds were used in 747's). She turned on her gamma meter - radiation levels were 8 times higher than normal inside her house. She informed the Nuclear Information ResourceService in Washington DC[Phone: 202-328-0002], and the EPA, FBI, HazMat and other emergency response gencies went to the Pentagon to investigate.
A pile of rubble from the crash was radioactive, but the EPA rep said "oh... it's probably depleted uranium... it's not a health hazard unless you breathe it". Firefighters, Pentagon personel, and communities nearby DID BREATHE IT. There was no followup investigation, and what about the World Trade Center in NY? Radiation almost never gets into the media. It is a taboo subject.
From: "Dr. H. D. Sharma"
[Physicist]
It does not matter whether the planes that hit the World-Trade Towers and the Pentagon have DU or not as long as DU does not catch fire. If DU catches fire -- most likely it will just like in the case of the El-Al plane that caught fire outside Amsterdam (Netherland), it will form aerosols of uranium dioxide. Inhalation of the aerosols can be harmful to human health depending on the quantity inhaled.
The presence of aerosols can be checked with the help of a simple radiation survey meter. Such meters are readily available and the site near the Towers should be checked for gamma-ray emitters as soon as possible. If you do not see any radiation from adioisotopes of thorium-234 and protoactinium-234, you are fairly certain that no DU has become airborne and it is unlikely to be harmful to human health.
Hari Sharma.
Even a few responsible members of the health physics community have questioned tritium's use in exit signs, and alternatives are being developed. On 9-11, hundreds of tritium exit signs were pulverized when the Twin Towers collapsed. The dust was also toxic with asbestos and other pollutants, as well as radioactive so-called "depleted" uranium (and more tritium) from the airplanes. Thousands of 9-11 emergency workers now suffer from lung problems. A 14-year-old boy had a temper tantrum and smashed ONE tritium-laced exit sign at a child care center. The hazardous waste cleanup cost taxpayers a quarter of a million dollars.
Tritium is used in a wide variety of consumer products such as illuminated watches, thermostat dials, and exit signs. Both the natural and human sources contribute to a worldwide background level of tritium.
Originally posted by Zaphod58
And do you have any idea how many NORMAL things in your life have small amounts of tritium in them? Or how much radiation? Smoke alarms for one (and I'm pretty sure there were a few of those around that got smashed).