Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
World renowned explosives experts Protec tells you why there is no evidence of an explosion at the WTC.
http://www.implosionworld.com/Article-WTC STUDY 8-06 w clarif as of 9-8-06 .pdf
The World Trade Center towers used neither a steel skeleton nor reinforced concrete. They were designed as square tubes made of heavy, hollow welded sections, braced against buckling by the building floors. Massive foundations descended to bedrock, since the towers had to be safe against winds and other lateral forces tending to overturn them. All this was taken into consideration in the design and construction, which seems to have been first-rate. An attempt to damage the buildings by a bomb at the base had negligible effect. The strong base and foundation would repel any such assault with ease, as it indeed did. The impact of aircraft on the upper stories had only a local effect, and did not impair the integrity of the buildings, which remained solid. The fires caused weakening of the steel, and some of the floors suddenly received a load for which they were not designed.
What happened next was unexpected and catastrophic. The slumped floors pushed the steel modules outwards, separating them from the floor beams. The next floor then collapsed on the one below, pushing out the steel walls, and this continued, in the same way that a house of cards collapses. The debris of concrete facing and steel modules fell in shower while the main structure collapsed at almost the same rate. In 15 seconds or so, 110 stories were reduced to a pile 9 stories high, mainly of steel wall modules and whatever was around them. The south tower collapsed 47 minutes after impact, the north tower 1 hour 44 minutes after impact. The elapsed times show that the impacts were not the proximate cause of collapse; the strong building easily withstood them. When even one corner of a floor was weakened and fell, the collapse would soon propagate around the circumference, and the building would be lost.
It is clear that buildings built in this manner have a catastrophic mode of failure ("house of cards") that should rule out their future construction. It is triggered when there is a partial collapse at any level that breaks the continuity of the tube, which then rolls up quickly, from top to bottom. The collapse has a means of propagation that soon involves the whole structure, bypassing its major strengths and impossible to interrupt. There is no need for an airliner; a simple explosion would do the job. There were central tubes in the towers, for elevators and services, but they appeared to play no substantial role in the collapse, and were not evident in the pictures or wreckage.
Every picture of "Ground Zero" is evidence of explosives used.
EVERYTHING but the steel was exploded into a huge pyroclastic cloud of dust BEFORE it even hits the ground.
If everything WASN'T exploded into dust then the rubble pile of the Twin Towers at Ground Zero would have been HUGE and MUCH HIGHER than it was.
The 110-story towers of the World Trade Center were designed to
withstand as a whole the forces caused by a horizontal impact of
a large commercial aircraft ~Appendix I!. So why did a total collapse
occur? The cause was the dynamic consequence of the prolonged
heating of the steel columns to very high temperature. The
heating lowered the yield strength and caused viscoplastic ~creep!
buckling of the columns of the framed tube along the perimeter of
the tower and of the columns in the building core. The likely
scenario of failure is approximately as follows.
In stage 1 ~Fig. 1!, the conflagration, caused by the aircraft fuel
spilled into the structure, causes the steel of the columns to be
exposed to sustained temperatures apparently exceeding 800°C.
The heating is probably accelerated by a loss of the protective
thermal insulation of steel during the initial blast. At such temperatures,
structural steel suffers a decrease of yield strength and
exhibits significant viscoplastic deformation ~i.e., creepan increase
of deformation under sustained load!. This leads to creep
buckling of columns ~Bazˇant and Cedolin 1991, Sec. 9!, which
consequently lose their load carrying capacity ~stage 2!. Once
more than half of the columns in the critical floor that is heated
most suffer buckling ~stage 3!, the weight of the upper part of the
structure above this floor can no longer be supported, and so the
upper part starts falling down onto the lower part below the critical
floor, gathering speed until it impacts the lower part. At that
moment, the upper part has acquired an enormous kinetic energy
and a significant downward velocity. The vertical impact of the
mass of the upper part onto the lower part ~stage 4! applies enormous
vertical dynamic load on the underlying structure, far exceeding
its load capacity, even though it is not heated. This causes
failure of an underlying multifloor segment of the tower ~stage 4!,
in which the failure of the connections of the floor-carrying
trusses to the columns is either accompanied or quickly followed
by buckling of the core columns and overall buckling of the
framed tube, with the buckles probably spanning the height of
many floors ~stage 5, at right!, and the upper part possibly getting
wedged inside an emptied lower part of the framed tube ~stage 5,
at left!. The buckling is initially plastic but quickly leads to fracture
in the plastic hinges. The part of building lying beneath is
then impacted again by an even larger mass falling with a greater
velocity, and the series of impacts and failures then proceeds all
the way down ~stage 5!.
how many buildings in the world have been built similar to wtc.....
Puts in a statement about controlled press too
Commander Dennis Henry, U.S. Navy Reserve (ret), BS CE, PE Retired from U.S. Navy Reserve, Civil Engineering Corps after 20 years of service. Retired Licensed Professional Engineer, State of Missouri. 34 years of service as a City Engineer, designing bridges, roadways, storm, sanitary sewers, and traffic signals.
"Being a civil engineer and understanding the laws of physics, I know that a building cannot fall at free fall speed without the floors already falling also giving no resistance. I wish our Congressmen were as smart, and also showed some backbone and got a truly independent investigation going. Also, this 911 truth movement has shown to me that our press is as every bit controlled and spits out as much propaganda as I thought Pravda did for the old Soviet Union. My eyes have been awakened to many things, and I have come to learn that we do not live in as free a country as I thought we did, and with the passage of the Patriot Act, the Military Commissions Act, it has become even less so."
There have been numerous reports detailing the cause of the World Trade Center Tower collapse on September 11, 2001. Most have provided qualitative explanations; however, simple quantitative analyses show that some common conclusions are incorrect; for example, the steel could not melt in these flames and there was more structural damage than merely softening of the steel at elevated temperatures
A computer simulation of the 2001 World Trade Center attacks supports a federal agency's findings that the initial impact from the hijacked airplanes stripped away crucial fireproofing material and that the weakened towers collapsed under their own weight.
The two-year Purdue University study, funded in part by the National Science Foundation, was the first to use 3-D animation to provide visual context to the attacks, said Christoph Hoffmann, a professor of computer science and one of the lead researchers on the project.
"One thing it does point out... is the absolute essential nature of fireproofing steel structures," Hoffmann told The Associated Press. "This is something that wasn't done originally in the World Trade Center when it was built. It wasn't code at that time."
Mete Sozen, a professor of structural engineering and a lead investigator on the simulation, said Purdue researchers hope their work leads to better structural design and building codes to prevent similar collapses.
"In the unfortunate development that we shall have to design structures to survive such events, the methods we have developed and will be developing will be of great use to designers," Sozen said.
The animation, intended in part to help engineers design safer buildings, begins with a map of lower Manhattan as it appeared on Sept. 11, 2001. The video then shows a plane slicing through several stories of the World Trade Center's north tower and follows the disintegrating plane through the interior and out the opposite side.
The report concludes that the weight of the aircraft's fuel, when ignited, produced "a flash flood of flaming liquid" that knocked out a number of structural columns within the building and removed the fireproofing insulation from other support structures, Hoffmann said.
The simulation also found that the airplane's metal skin peeled away shortly after impact and shows how the titanium jet engine shafts flew through the building like bullets.
Ayhan Irfanoglu, a Purdue professor of civil engineering, said half of the building's weight-bearing columns were concentrated at the cores of the towers.
"When that part is wiped out, the structure comes down," Irfanoglu said. "We design structures with some extra capacity to cover some uncertainties, but we never anticipate such heavy demand coming from an aircraft impact. If the columns were distributed, maybe, the fire could not take them out so easily."
This photograph shows the south tower just as it is collapsing. It is evident that the building is falling over to the left. The North Tower collapsed directly downwards, on top of itself. The same mechanism of failure, the combination of impact and subsequent fire damage, is the likely cause of failure of both towers. However, it is possible that a storey on only one side of the South Tower initially collapsed, resulting in the "skewed" failure of the entire tower.
The gigantic impact forces caused by the huge mass of the falling structure landing on the floors below travelled down the columns like a shockwave faster than the entire structure fell. The clouds of debris coming from the tower, several storeys below the huge falling mass, probably result from the sudden and almost explosive failure of each floor, caused by the "shockwave".
Why the World Trade Center Towers Fell
* It was the simultaneous fires, on multiple floors, rather than burning jet fuel (much of which was consumed in the initial fireballs), that weakened the structural steel elements enough to precipitate the collapse.
* Robust and redundant steel framing, adequate and well-lighted stairways, and emergency training contributed to the towers' resilience and the safe egress of occupants.
* Lightweight fireproofing, probably blown off of the structural steel, sprinkler supply pipes severed by flying debris, gypsum wallboard around the stairwells, which collapsed and blocked access, and the grouping of stairwells in the buildings' core, which increased their vulnerability to a single impact, may have contributed to the collapse or hindered the escape of occupants above the impact zones.
I dare say that Toro took some people to school tonight.
With the press of a button at 5:47 PM on October 24, 1998, Detroit Mayor Dennis Archer dropped the J.L. Hudson Department Store from his city’s skyline and into the history books and record books.
Hudson’s was the tallest department store in the country and was second in square footage only to Macy’s anchor Store in New York. It dominated the retail market in the city through the 1970’s before closing its doors in 1983.
The store was built in 12 separate stages, the first in 1911 and the last in 1946. The complex had two retail basements and 23 above grade retail floors, including mezzanines. Two additional basements and six upper stories in a tower, provided storage and mechanical support for the 2.2 million square foot building. In all there were 33 levels in the structure.
Under CDI direction, Homrich/NASDI’s 21 man crew needed three months to investigate the complex and four months to complete preparations for CDI’s implosion design. During that period, the lower two basements of the structure were filled with engineered fill and the perimeter basement walls bermed to 1st basement level with soil to support perimeter walls which would surely have failed under soil and hydrostatic loads once the horizontal support of the Hudson’s internal structure was removed by the implosion.
CDI’s 12 person loading crew took twenty four days to place 4,118 separate charges in 1,100 locations on columns on nine levels of the complex. Over 36,000 ft of detonating cord and 4,512 non-electric delay elements were installed in CDI’s implosion initiation system, some to create the 36 primary implosion sequence and another 216 micro-delays to keep down the detonation overpressure from the 2,728 lb of explosives which would be detonated during the demolition.
Why would NIST try to forensically analyse collapse without the building plans? NO where in their product does it say they had plans.
Why would NY state courts let guiliani steel the NYC building plans when NIST needed them for engineering analysis? They ignored federal and state freedom of information laws.
Why would thousands of tons of steel(evidence) go to India and China when the US steel industry needs the steel?
