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www.carba.co.uk...
However, it is interesting to see what happened on the 9th level. The picture shows that the unprotected steel mullions buckled as they were restrained against thermal expansion. But collapse did not ensue. Why?
The answer is that the loads were taken by multiple alternative load paths – a classic robustness provision. Mullions above from level 10 to 17 and below from level 8 down were able to distribute and share the loads as the 9th level mullions failed. The fact that there were 60 mullions per floor level added to the number of alternative load paths available.
Why was it that although these
alternative load paths existed above the
17th level they did not apparently
prevent the collapses? There are two
answers to this – firstly because there was no effective fire compartmentation of the building; secondly because of the failure of two internal concrete columns. Yes, a portalised pair of 1200 x 500 concrete columns did collapse.
The fire started on the 21st floor level. As shown in the picture taken from the east after the fire, the serviced storey between 16th and 17th levels arrested all the progressive collapse that occurred to the upper superstructure. Such “strong floors” in multi-storey buildings are another classic robustness provision.
originally posted by: neutronflux
a reply to: LaBTop
LT : The atomic explosion diagram is CLEARLY characterized by a really huge spike at the onset.
Can you even try to acknowledge those two HUGE spikes in the above 911 diagram ???
It's the only honestly showing amplitudes diagram for all 4 first events, ever given by LDEO.
1. But what type of wave is that spike? P waves? S waves? Surface waves? Love waves? Rayleigh waves?
2. Is it true the detonation of explosives historically create specific types of seismic waves? And LDEO has a seismic history of previous detentions. And is it false a building collapse without the aid of explosives will not create seismic waves associated with the detention of explosives?
3. Does your seismic evidence show waves associated with the detention of explosives. It has nothing to do with the amplitude of the wave’s spike if that wave is not solely associated with the detention of explosives.
4. If there was seismic evidence of conventional CD, why did AE, Richard Gage, and Steven Jones abandon conventional CD for fizzle no flash / thermite heat based cutting? Are they false flag deniers?
5. Dr Wood has repeatedly debunked seismic evidence of CD at the WTC? Is she a false flag denier?
The composition of the waves is revealing both in terms of the location of the source and the magnitude of the energy transmitted to the ground. The subterranean origin of the waves emitted when WTC1 collapsed is attested by the presence of the P and S body waves along with the Rayleigh surface waves. The placement of the source of the four other explosions is sub-aerial, attested by the unique presence of only Rayleigh waves.
Originally posted by: neutronflux
A reply to: LaBTop
Winning side? Things like not understanding there is no seismic evidence of conventional explosives at the WTC killed the credibility of the truth movement long ago. There is a reason why AE abandoned conventional explosives long ago. There is no proof of detonations that created a pressure wave with the energy to cut steel columns.
By the way, P and S body waves are much smaller in amplitude and energy and propagate through the earth's upper crust somewhat faster than Rayleigh wave
www.ldeo.columbia.edu...
Comparison with Signals from Earthquakes, Gas Explosion and Mine Collapse
The signals at PAL from Collapse 2 and a small felt earthquake beneath the east side of Manhattan on January 17, 2001 are of comparable amplitude and ML (Fig. 4). The character of the two seismograms, however, is quite different. Clear P and S waves are seen only for the earthquake. The 7-km depth of the earthquake suppressed the excitation of short- period Rg, which is so prominent for the collapse. The difference in the excitation of higher frequencies also can be attributed to the short time duration of slip in small earthquakes compared to the combined source time of several seconds of the complex system of the towers and foundations responding to the impacts and collapses. The waves from the WTC events resemble those recorded by regional stations from the collapse of part of a salt mine in western New York on March 12, 1994 (ML 3.6). That source also lasted longer than that of a small earthquake. A truck bomb at the WTC in 1993, in which approximately 0.5 tons of explosive were detonated, was not detected seismically, even at a station only 16 km away.
An explosion at a gasoline tank farm near Newark NJ on January 7, 1983 generated observ- able P and S waves and short-period Rg waves (ML 3) at PAL. Its Rg is comparable to that for WTC collapse 2. Similar arrivals were seen at station AMNH in Manhattan, which is no longer operating, at a distance of 15 km. AMNH also recorded a prominent seismic arrival at the time expected for an atmospheric acoustic wave. We know of no microbarograph recordings of either that explosion or the events at the WTC. Many people asked us if the arrivals at seismic stations from the WTC events propagated in the atmosphere. We find no evidence of waves arriving at such slow velocities. Instead the seismic waves excited by impacts and collapses at the WTC are short-period surface waves, i.e. seismic waves traveling within the upper few kilometers of the crust.
Originally posted by: neutronflux
A reply to: LaBTop
www.carba.co.uk...
However, it is interesting to see what happened on the 9th level. The picture shows that the unprotected steel mullions buckled as they were restrained against thermal expansion. But collapse did not ensue. Why?
The answer is that the loads were taken by multiple alternative load paths – a classic robustness provision. Mullions above from level 10 to 17 and below from level 8 down were able to distribute and share the loads as the 9th level mullions failed. The fact that there were 60 mullions per floor level added to the number of alternative load paths available.
Why was it that although these alternative load paths existed above the17th level they did not apparently prevent the collapses? There are two answers to this – firstly because there was no effective fire compartmentalization of the building; secondly because of the failure of two internal concrete columns. Yes, a portaled pair of 1200 x 500 concrete columns did collapse.
The fire started on the 21st floor level. As shown in the picture taken from the east after the fire, the serviced story between 16th and 17th levels arrested all the progressive collapse that occurred to the upper superstructure. Such “strong floors” in multi-story buildings are another classic robustness provision.
1. The towers did not have a traditional concrete core. Floors were only supported on the ends of the floor trusses.
2. WTC 7 was not as open as the towers, but had floor connections not at traditional angles.
3. The WTC buildings did not have “classic robustness provision“ that prevented the total collapse of the Madrid Windsor. is that a false statement?
911review.com...
There appears to be no basis for the claim that the large spikes preceded the "collapses", nor that the energy indicated by those spikes was more than could be accounted for by the approximately 110 megawatt-hours of gravitational energy stored in the elevated mass of each Tower. And there is strong evidence contradicting the idea that the seismic spikes indicated underground explosions including:
There is no support in the large body of photographic and video collapse evidence for the idea of powerful explosions in the Towers' basements at the onset of the collapses. Instead the evidence shows waves of destruction proceeding methodically downward from the crash zones to the ground.
Underground explosions would have produced strong P waves, but the seismic stations registered only strong S waves. P waves oscillate horizontally -- parallel to the direction of travel; whereas S waves oscillate vertically -- perpendicular to the direction of travel.
An analysis of the timeline of the North Tower collapse on the 9-11Research site corroborates the idea that the large seismic spikes were produced by rubble reaching the ground.
The amplitude of a periodic variable (LT : wave) is a measure of its change over a single period. There are various definitions of amplitude, which are all functions of the magnitude of the difference between the variable's extreme values. In older texts the phase is sometimes called the amplitude.
snip
Maximum magnitude computes the maximum value of the absolute value of the amplitudes within a timed window.
( en.wikipedia.org... )
Similar arrivals were seen at station AMNH in Manhattan, which is no longer operating, at a distance of 15 km.
originally posted by: LaBTop
originally posted by: LaBTop
""and claiming only one did"". HuH?
Yup
Two steel framed construction collapses there
Only the upper few, outer floor steel parts of the Windsor Tower in Madrid PARTIALLY collapsed, since those were the ones where the spray-on insulation wasn't attached yet. When the partial collapse reached the floor where it WAS attached everywhere, the collapse sequence immediately got halted by the still intact, unbend or weakened steel.
the-pre-collapse-inward-bowing-of-wtc2.t4760/
www.metabunk.org...
en.m.wikipedia.org...
Detonating cord is also employed directly in building demolition where thin concrete slabs need be broken via channels drilled parallel to the surface, an advantage over dynamite since a lower minimum of explosive force may be used and smaller diameter holes are sufficient to contain the explosive.[2] Anything much more substantial than these uses requires the use of additional explosives.
This article reveals that there were cabling ducts located underneath the metal floorpans which could be used for simple cable installation