The Real Story of the Twin Towers Bombed in New York and What They Really Symbolized

Fifteen years ago, on September 11, 2001, the World War II complex was bombed in New York. shopping center. 2996 people were killed, over 10 thousand were injured of varying severity. Both Twin Towers have ceased to exist. Another building of the complex, the Marriott Hotel, was buried under the rubble of the first tower. The frames of the four others survived, but they were deemed beyond repair and demolished.

Idea

The idea to build the World Trade Center (WTC) in Manhattan was proposed by the famous billionaire brothers back in the late 1950s. David and former mayor of New York at the time Nelson Rockefellers. They were supported by the local Port Administration. Construction of the complex began in 1966 and cost, according to some estimates, $1.5 billion.

The World Trade Center skyscrapers were designed by an American modernist architect Minoru Yamasaki, who is believed to have won the competition because he proposed to build the towers quickly and cheaply. He worked together with Antonio Brittaiocchi and by Emery Roth & Sons. Before starting to build the two giants of steel, glass and concrete, Yamasaki created hundreds of models. Perhaps he felt that the most grandiose and modern building in the world at that time would become his swan song and therefore tried to express his idea in it. “The World Trade Center should be a symbol of faith in the power of man,” the architect said more than once.

When creating the project, Yamasaki mixed his Gothic tastes and the architectural and ethical ideas of the great Le Corbusier. Subsequently, some critics called the architectonics of the WTC towers limited and boring, and the poverty of form, in their opinion, served as an “indicator of internal disaster.” Some considered these buildings to be the embodiment of the existing social system in the United States.

When the first of the colossi appeared in New York, critics called it “the biggest finger in the sky.” A specialist in technical history Lewis Mumford regarded Twin Towers as "an example of the unintentional gigantism and technological exhibitionism that is now eviscerating the living fabric of every great city." Many people also did not like the narrow (only 46 cm wide) windows of the office premises of the towers. According to the prevailing opinions at that time, the architect made them this way because he was terribly afraid of heights.

However, there was also an opinion that the skyscrapers of the World Trade Center represented a man and a woman. As confirmation, it was pointed out that Yamasaki emphasized the male tower with an elastic antenna, and the female tower with an observation deck gateway. He and She seemed to be on the move towards the Hudson and all of America. The woman, as always, was half a step behind. Perhaps this was an architectural representation of Adam and Eve leaving Paradise? The architect himself definitely did not speak out on this matter.

Design

Dozens of low-rise buildings were demolished to clear space for a grandiose construction project near the city's port. 1.2 million cubic yards of earth were removed and transported to create a 21-meter-deep foundation under the skyscrapers and the Plaza, an underground space that later housed shops, restaurants, banks, airline ticket offices, travel agencies, a new metro station, and maintenance workshops for the twin towers. , warehouses and an underground garage for 2 thousand cars.

When building skyscrapers, an engineering idea was used that was first used to create the IBM office center in Seattle. In this case, the designers also used a structural model of a rigid “hollow tube” of closely spaced columns with a diameter of 990 mm, with floor trusses 83 cm thick, expanding towards the central part. Many steel columns inside the building became the load-bearing part that supported the entire building. The “stiffening ribs” were complex-profile steel floors. This concept made it possible to create spacious spaces inside, not cluttered with unnecessary structures.

The buildings' 64.5 m wide façade was a prefabricated steel lattice with columns 476.25 mm wide. They protected the entire structure from wind and other external overturning loads. The location of the “wind supports” outside the surface of the building prevented the transfer of forces through the membrane of the floors to the center. There were 61 steel beams along each of the four sides of the building along the entire height. Cables were stretched between them along the entire height. They, as well as a package of cables inside the elevator shafts, provided design flexibility. In general, the towers were a combination of steel cages from factory-produced modules measuring 10x3 m and weighing 22 tons. The external columns of the buildings were finished with a silver aluminum alloy. This gave the impression that the skyscrapers had no windows at all. Although there were as many as 43 thousand of them.

The Twins were the first supertall buildings designed without masonry. A special “dry-wall” system was developed for them, fixed in a reinforced steel base. The floors were supported by a series of lightweight trusses on rubber panels located between the outer columns and the elevator section. Both “brothers,” as the designers claimed, were able to withstand hurricane wind and were supposed to withstand even if rammed by a medium-sized aircraft, such as a Boeing 707.

They were constructed mainly from glass, steel and concrete using duralumin and durable titanium. In total, about 400 thousand cubic meters were needed for construction. m of cement, 200 thousand tons of steel and 20 thousand sq. m. m glass.

Operation

The first tower was built by 1970. But officially the World Trade Center in New York was opened only on April 4, 1973 after the second one was put into operation. The complex included five more ground-based structures. Among them are the high-rise Marriott Hotel, a commodity exchange and the 8-story palace of the American Customs House. 8 floors in both high-rise buildings (7-8, 41-42, 75-76 and 108-109) were technical. All others, with a total area of ​​more than 1 million square meters. m, were rented.

The height of the World Trade Center skyscrapers (North Tower - 110 floors, 417 m, South Tower - 104 floors, 415 m) was a constant topic of jokes and anecdotes at that time. Here's one of them. At a press conference after the opening ceremony of the World Trade Center, Yamasaki was asked: “Why two buildings of 110 floors each? Why not one in 220? His answer: “I didn’t want to lose the human scale.”

In the 1990s, the World Trade Center towers housed 10% of all the offices in lower Manhattan. Almost 500 companies had offices there. Thus, in the South Tower, 25 floors for the head office were rented by the investment corporation Morgan Stanley, which manages capital worth $487 billion, and 5 floors were occupied by the Oppenheimer fund with a “modest” $125 billion under management. Fuji Bank was located on four floors . 3 floors each were occupied by the New York Stock Exchange, the insurance company AON, the telecommunications company Verizon (capitalization $17.5 billion), the architectural firm Manciani Duffi (recognized as the best interior designer in 2000) and the law firm Thacher, Proffit & Wood . The computer corporation Sun Microsystems, the New York State Department of Taxation and Finance, and the insurance agency Frenkel&Co had modest, only 2 floors.

On a typical day, 50 thousand employees and 200 thousand visitors and tourists came to work at the World Trade Center. On the 107th floor of the North Tower there was a fashionable and expensive restaurant “Windows to the World”. Americans loved to celebrate weddings there and celebrate various significant events. In the 1990s, tens of thousands of tourists climbed to the observation deck of the South Tower every day. On a clear day, through the suicide fence, they could survey the surrounding area within a radius of 78 km.

The system of 99 elevators in skyscrapers was designed in such a way that high-speed lifts from below went to the beginning of the 2nd and 3rd sections of the building, starting on the 44th and 78th floors. From there, “local” elevators took passengers to the desired floor. Each sectional elevator could lift 55 people at a speed of about 8.5 m per second. In total, the World Trade Center complex had 239 elevators and 71 escalators, which were controlled by a computer center. The windows in the two towers were washed automatically 3 times a week using special machines on moving steel cables.

Destruction

The great design advantage of the New York twins was that the buildings' steel beams were connected to supports located less than a meter apart, forming the building's outer walls. While the vertical supports of most other American skyscrapers are located at a distance of up to 6 m from each other, and the main load in them is transferred to the combined diagonal pillars, damage to which, as a rule, leads to the immediate destruction of the entire building.

The downside was the lack of foam fire-fighting systems that could cope with burning aviation fuel. Concrete is guaranteed to withstand flames for an hour or two. But 91 thousand liters of aviation fuel, which were used to fill both planes sent by terrorists to the World Trade Center buildings, turned the winged cars into thermal bombs. When the combustion temperature exceeded 800 °C, the steel supports began to melt. However, it was later discovered that this was not the main reason for the collapse of Gemini.

A few years after the tragedy, experts unequivocally established that the cause of the collapse was a gradual shift in the center of gravity in the buildings as a result of a fire. The outer columns could not withstand the extraordinary stress.

Oleg KLIMOV

(based on materials from foreign press)

FOR REFERENCE: Minoru Yamasaki — American architect who combined the international style with neoclassical features. Born in Seattle, USA, December 1, 1912 in Japanese family who had American citizenship.

In 1949 he founded his own company. In 1951 he received an award from the American Institute of Architects for a residential complex in St. Louis, USA. True, already in 1972 these buildings were destroyed as “morally obsolete and socially burdensome.”

Among the most famous buildings designed by Minoru Yamasaki are the US Consulate in Kobe, Japan (1955), Lambert Airport in St. Louis, USA (1956), Memorial community center McGregor in Detroit, USA (1958), Dhahran Airport, Saudi Arabia (1961) and Eastern Province Airport in Riyadh (1985).

He built skyscrapers and at the same time was terrified of heights. While working on the WTC buildings, Minoru Yamasaki divorced his wife, married another, then divorced and married again, then again. Eventually he divorced again and returned to his first wife.

Finite element model of the World Trade Center floor to evaluate the building's structural system

The dimensions of the structure in plan are 63.4x63.4 m, the rigidity cores are 26.8x42.1 m. The WTC towers were designed as a “pipe-in-pipe” (stem structural design) in order to create a continuous space on the floors, not divided walls or columns. This was achieved due to the fact that the outer wall of the tower, in fact, was a set of columns installed side by side, taking on the main vertical load, while the wind load fell mainly on the power columns located in the center of the tower (stiffness core). Starting from the tenth floor, each wall of the tower was composed of 59 columns, 49 power columns were installed in the center of the tower All elevators and staircases passed through the rigidity core, leaving large free space between the core and the perimeter of the tower to accommodate offices.

The floor structure consisted of 10 cm of lightweight concrete laid on permanent formwork made of profiled decking. The corrugated sheeting was laid on secondary (auxiliary) trusses (beams), supported by the main trusses, transmitting the load to the central and peripheral columns. The main trusses had a length of 11 and 18 meters (depending on the span), and were laid in increments of 2.1 m, and were attached from the outside to lintels connecting the peripheral columns at the level of each floor, and from the inside to the central columns. The floor was secured through elastic dampers designed to reduce the impact of building vibrations on the people working in it.

This truss system allowed optimized load redistribution of the floor diaphragms between the perimeter and core, with improved performance between the different materials of flexible steel and rigid concrete allowing the moment structure to transfer influence into compression on the core, which also mainly supported the transmission tower.

The towers also included an "outrigger truss" located between the 107th and 110th floors, which consisted of six trusses along the longitudinal (long) axis of the core and four along the short (transverse) axis, which served to redistribute the load and increase the overall stability of the building, and also to support the antenna spire, which was installed on only one of the towers. NIST determined that this structure played a key role in the sequence of events leading to the complete destruction of the towers.

Possibility of resisting fire and aircraft hits

Like all modern high-rise buildings, the WTC towers were designed and built to withstand a normal fire. Many fire safety features were incorporated during the design and construction phase, and others were added after a 1975 fire that consumed six floors before being contained and extinguished. Tests carried out before the disaster showed that the steel structures of the towers met or even exceeded current fire resistance requirements.

The structural engineers who designed the World Trade Center considered the possibility that a plane could collide with the building. In July 1945, a B-25 Mitchell bomber became disoriented in fog and crashed into the 79th floor of the Empire State Building. A year later, a twin-engine C-45 Beechcraft collided with the skyscraper at 40 Wall Street, and another plane came close to another collision with the Empire State Building.

NIST stated that “American Building Standards do not include requirements for the resistance of buildings when struck by an aircraft. … and thus buildings are not designed to withstand the impact of a fully fueled commercial airliner.” , nevertheless, the designers and architects of the World Trade Center discussed this problem and recognized its importance. Leslie Robertson, one of the chief engineers of the World Trade Center, recalled that the scenario considered was that a Boeing 707 jet would hit the building, disorientated in fog and flying at relatively low speed in search of JFK Airport or Newark Liberty Airport. John Skilling, another WTC engineer, said in 1993 that his subordinates carried out an analysis that showed that the biggest problem if the WTC towers collided with a Boeing 707 would be that all the plane's fuel would end up inside the building and lead to a "terrible fire." and many casualties, but the building itself will remain standing. FEMA wrote that the World Trade Center buildings were built to withstand a collision with a Boeing 707 jet airliner, which weighs 119 tons and has a speed of about 290 km/h, much less in weight and speed than the aircraft used in the September 11 attacks.

NIST found in the archives a three-page report summarizing a study that simulated a Boeing 707 or Douglas DC-8 hitting a building at 950 km/h. The study showed that the building should not collapse as a result of such a hit. But, as NIST experts noted, “the 1964 study did not model the effect of a fire caused by jet fuel spraying into a building.” NIST also noted that in the absence of initial calculations used to model the situation, further comment on this topic would be largely “speculation.” Another document found by NIST was a calculation of the period of oscillation of a building if a plane struck the 80th floor of the World Trade Center tower, but it made no assumptions about the fate of the building after the impact. A property risk assessment report prepared for Silverstain Properties considered the possibility of an aircraft hitting the World Trade Center towers as unlikely but possible. The report's authors cited WTC structural engineers who said the towers should have withstood a collision with a large passenger plane, but burning fuel flowing from the plane to ground level would have damaged the building's skin. Some of the documents related to the analysis of the scenario of an aircraft hitting the towers were lost as a result of the destruction of WTC 1 and WTC 7, which contained documents from the Port Authority of New York and New Jersey and Silverstain Properties.

Aircraft hitting towers

The terrorists flew two Boeing 767 jet airliners, American Airlines Flight 11 (767-200ER) and United Airlines Flight 175 (767-200), into the towers. The North Tower (1 WTC) was hit at 8:46 am by Flight 11, between the 93rd and 99th floors. Flight 175 crashed into the south tower (2 WTC) at 9:03, between floors 77 and 85.

The Boeing 767-200 airliner has a length of 48.5 m, a wingspan of 48 m, and carries on board from 62 tons (-200) to 91 tons (-200ER) of aviation fuel. The planes crashed into the towers at very high speed. Flight 11 was traveling at approximately 700 km/h when it struck the north tower; Flight 175 crashed into Southern at a speed of about 870 km/h. In addition to the fact that the hits caused severe damage to the supporting columns, they caused the explosion of approximately 38 tons of aviation fuel in each tower, which led to the almost immediate spread of a large fire on several floors containing office furniture, paper, carpeting, books, and other flammable materials. The shock wave from hitting the north tower spread down to the first floor, along at least one high-speed elevator shaft, and broke glass on the first floor, causing injuries to several people.

Fire

The lightweight construction of the towers and the lack of solid walls and ceilings led to the fact that aviation fuel spread throughout a fairly large volume of buildings, leading to numerous fires on several floors close to the impact areas of the aircraft. The aviation fuel itself burned out within a few minutes, but combustible materials in the building itself maintained intense fires for another hour or hour and a half. It is possible that if more traditional structures had been in the path of the aircraft, the fires would not have been so centralized and intense - aircraft debris and aviation fuel could have remained primarily in the peripheral area of ​​the building, rather than penetrating directly to its central part. In this case, the towers might have survived, or in any case, would have stood much longer.

Development of the situation

• 9:52 - A fire department helicopter radios that “large pieces of the building may fall from the upper floors of the south tower. We are seeing large parts of the building in limbo.”

• 9:59 - a helicopter reports that the south tower is falling.

Helicopters also reported the development of the situation with the north tower of the World Trade Center.

• 10:20 - Fire Department helicopter reports that the upper floors of the north tower may be unstable.

• 10:21 - it is reported that the south-eastern corner of the tower is warped, and that the tower is beginning to lean towards the south.

• 10:27 - it is reported that the roof of the north tower may collapse at any minute.

• 10:28 am - The fire department receives a report that the north tower has collapsed.

Overload of dispatchers and bad job Communications led to the fact that the fire and police departments of New York had great difficulty in ensuring timely communication, both with their departments and with each other. As a result, the fire brigades located in the towers did not receive orders to evacuate and 343 firefighters died when the buildings collapsed.

WTC towers collapse

The south tower collapsed at 9:59 a.m., 56 minutes after impact. The north tower stood until 10:28, 102 minutes after the plane hit it. The collapsed towers created a huge cloud of dust that covered much of Manhattan. In both cases, a similar process occurred, the upper damaged part of the building collapsed onto the lower floors. Both towers fell almost vertically, although there was a significant deviation from the vertical of the top of the southern tower. Debris and dust were also observed flying from the windows of the building below the rapidly advancing collapse zone.

Tower collapse mechanism

The NIST investigation found that because the planes hit the towers in different ways, the process of destruction of the north and south towers was also slightly different, although it was generally the same in both cases. After being hit by the planes, the internal power columns were seriously damaged, although the external columns suffered relatively little damage. This caused a serious redistribution of the load between them. The upper power structure of the towers played a significant role in this redistribution.

Aircraft that struck buildings stripped fire-resistant coatings from large portions of steel structures, exposing them to direct fire. In the 102 minutes preceding the collapse of the north tower, the temperature of the fire, although well below the melting point of the metal, had reached a sufficient magnitude to cause the weakening of the strength columns in the center of the building, which began to deform and bend under the weight of the upper floors. The NIST report describes this situation as follows:

You can imagine the central load-bearing frame of the north tower in the form of three sections. The lower section (below the destruction zone) was a rigid, stable, intact structure with a temperature close to normal. The upper section, above the destruction zone, was also a rigid box, which also had a lot of weight. The middle section, located between them, was damaged by the impact and explosion of the aircraft, and was also weakened by the fire. The upper part of the load-bearing frame tended to fall lower, but it was held in place by the upper truss structure resting on the peripheral columns. As a result, this design created a large load on the perimeter of the building. Original text(English) At this point, the core of WTC 1 could be imagined to be in three sections. There was a bottom section below the impact floors that could be thought of as a strong, rigid box, structurally undamaged and at almost normal temperature. There was a top section above the impact and fire floors that was also a heavy, rigid box. In the middle was the third section, partially damaged by the aircraft and weakened by heat from the fires. The core of the top section tried to move downward, but was held up by the hat truss. The hat truss, in turn redistributed the load to the perimeter columns. NIST Report, page 29

A similar situation occurred in the south tower (the internal power columns were seriously damaged). The peripheral columns and floor structures of both towers were weakened by the fire, causing the floors on the damaged floors to settle and placing significant stress on the peripheral columns towards the interior of the building.

At 9:59, 56 minutes after impact, the settling floor caused severe inward bending of the outer columns on the east side of the south tower, the upper structure transferred this bending force to the central columns, causing them to collapse and the beginning of the collapse of the building, the upper part of the tower in the process deviated towards the damaged wall. At 10:28 a.m., the south wall of the north tower buckled, causing approximately the same sequence of events. As a result of the subsequent collapse of the upper floors, the complete destruction of the towers became inevitable, due to the enormous weight of the part of the buildings that were located above the damage zone.

The reason that the northern tower stood longer than the southern one was a combination of the following three factors: the area where the aircraft hit the northern tower was higher (and the weight of the upper part of the building, accordingly, less), the speed of the aircraft that hit the tower was lower, in addition, the aircraft hit floors whose fire protection has previously been partially improved.

The theory of complete progressive collapse

Ruins of the South Tower (right) and North Tower (left), as well as other World Trade Center buildings

A huge cloud of dust obscured the collapsing towers, making it impossible to determine the exact duration of the destruction based on visual evidence.

Because the NIST report focuses primarily on the mechanisms of the initial collapse, it does not address the subsequent complete collapse of both WTC towers. Initial analyzes explained the collapse by saying that the kinetic energy of the falling upper floors was much greater than what the floors could withstand, which also collapsed, adding kinetic energy to the falling building. This scenario was repeated with increasing speed until the towers were completely destroyed. Although this is the most widely accepted view among civil engineers, it has been criticized for not taking into account the resistance of the underlying structures, which should have slowed, or even stopped, the collapse of the towers.

7 WTC building collapse

FEMA's initial study was inconclusive, and the collapse of 7 WTC was not included in the final NIST report released in September 2005. Except for the letter published Metallurgical Journal, which suggested that the building's steel frame could have melted in a fire, no other studies of this issue were published in scientific journals. The 7 WTC crash was investigated separately from the 1 WTC and 2 WTC crashes, and in June 2004, NIST released a working report that contained several hypotheses about what happened. One hypothesis was the destruction of one of the building's critical support columns, caused by fire or large debris from falling towers, leading to "disproportionate collapse of the entire structure."

NIST diagram showing the bending of Column 79 (circled in orange) that began the progressive collapse of the building.

The order of destruction of 7 WTC in the diagram from the 2004 NIST preliminary report. Column 79 is marked with a circle in the center of the red zone.

NIST's 7 WTC fall model. In the first part of the video, columns 81, 80 and 79 are depicted from left to right.

On November 20, 2008, NIST published the final report on the fall of 7 WTC. The NIST report cited fire as the main cause of destruction, along with a lack of water for firefighters and the automatic fire suppression system to fight the fire. NIST reconstructs the sequence of events as follows: At 10:28 a.m., debris from the falling 1 WTC caused damage to the nearby 7 WTC. Fires also broke out, likely from burning debris from 1 WTC. Firefighters immediately arrived at 7 WTC, but at 11:30 they discovered that there was no water in the fire hydrants to fight the fire - the water came from the city water supply system, destroyed as a result of the falls of towers 1 WTC and 2 WTC. New York City Fire Department ( English), fearing for the lives of firefighters in the event of the destruction of 7 WTC, at 14:30 he recalled the firefighters and stopped fighting to save the building. The fire was observed on 10 floors from the 7th to the 30th, and on floors 7-9 and 11-13 the fire got out of control. Thermal expansion of the beams heated to approximately 400 °C around column 79 in the eastern part of the building in the area of ​​the 13-14th floor led to the failure of the fire-weakened floors adjacent to column 79 from the 13th to the 5th floor. The destruction of the floors deprived column 79 of horizontal support, and it began to bend, which was the immediate cause of the complete destruction of the building within a few seconds. The bending of column 79 led to the transfer of the load to columns 80 and 81, which also began to bend, as a result of which all the floors associated with these columns were destroyed up to the top of the building. The falling floors destroyed truss 2, which led to the fall of columns 77, 78 and 76. As a result of the increased load transferred from the bent columns, the falling of fragments of the floors from above, and the lack of horizontal support from the destroyed floors, all internal columns from east to west began to bend sequentially. Following this, in the area of ​​floors 7-14, the outer columns began to bend, to which the load was transferred from the lowered inner columns and the center, and all floors above the bent columns began to fall down as a single whole, which completed the final destruction of the building at 17:20.

Some authors criticized the city authorities' decision to locate the 7 WTC headquarters on the 23rd floor Office of Emergency Situations(English) Office of Emergency Management ). It was believed that this could have been a significant factor in the destruction of the building. Particularly noted was the placement of large diesel fuel tanks in the building, which were supposed to serve to power emergency power generators. NIST concluded that diesel fuel did not play a role in the destruction of the building, but the rapid evacuation of the Office of Emergency Management was a contributing factor to the poor communication between various agencies and the loss of control over the situation. The main cause of the building's destruction was fire; damage from debris from the falling 1 WTC accelerated the fall of the building, but NIST calculations showed that 7 WTC would have collapsed from an uncontrolled fire alone.

Progress of investigations

First reaction

The destruction of the World Trade Center towers came as a surprise to construction engineers. “Before September 11,” the magazine wrote New Civil Engineer“We quite sincerely could not imagine that a structure of such a scale could suffer such a fate.” Although the damage from the aircraft was severe, it only affected a few floors of each building. The challenge for engineers was to figure out how such local damage caused the complete progressive collapse of three of the world's largest buildings. In an October 2001 BBC interview, English architect Bob Halvorson aptly predicted that there would be much "debate about whether the World Trade Center could have collapsed the way it did." A full analysis would include architectural and structural plans of the World Trade Center, witness testimony, videos of the destruction, debris survey data, etc. Underscoring the complexity of the task, Halvorson said the destruction of the World Trade Center towers is "far beyond the realm of normal experience."

Research credibility

Immediately after the disaster, there was a situation of uncertainty as to who had sufficient authority to conduct an official investigation. Contrary to the practice found in air crash investigations, clear procedures for investigating building collapses simply did not exist.

A short time after the disaster at the base Institute of Civil Engineers(English) Structural Engineers Institute (SEI)) American Society of Civil Engineers(English) American Society of Civil Engineers ASCE), a working group was created, which also involved specialists American Institute of Steel Construction(English) American Institute of Steel Construction ), American Concrete Institute(English) American Concrete Institute ), National Fire Protection Association and Fire Protection Engineering Society(English) Society of Fire Protection Engineers ) . ASCE also invited the Federal Emergency Management Agency (FEMA) to join the work of this group, which later received joint ASCE-FEMA control. This investigation was subsequently criticized by American engineers and lawyers, however, the authority of the above-mentioned organizations was sufficient to conduct the investigation and to provide access to the disaster site for the group's experts. One of the most poignant aspects of the investigation was that clearing the disaster site actually led to the destruction of the remaining components of the building. Indeed, when NIST published its final report, it noted a “lack of physical evidence” as one of the main problems of the investigation. Only a fraction of a percent of the building's remains remained available for investigation after the clearance work was completed, with a total of 236 individual steel fragments recovered.

FEMA released its report in May 2002. Although NIST had already announced its involvement in the investigation in August of that year, in October 2002, under increasing public pressure for a more detailed investigation, Congress passed a bill to create a new group under NIST, which published its report in September 2005.

FEMA's "stack of pancakes" theory

In its early investigations, FEMA developed a theory to explain the collapse of the World Trade Center towers, called the "stack of pancakes" theory. pancake theory). This theory was defended by Thomas Iga and was widely covered by PBS. According to this theory, the connection between the lintels supporting the floor and the columns of the building failed, causing the floor to collapse on the floor below, placing loads on its structure that it was not designed for. Some individual publications have proposed other sets of factors that caused the collapse of the towers, but overall this theory has been accepted by most.

Fires remained the main key factor in this theory. Thomas Iga, a professor of materials science at MIT, described the fires as "the most baffling part of the collapse of the World Trade Center towers." Although the fires were initially thought to have "melted" the steel structures, Iga stated that "the temperatures of the fires in the WTC towers were unusually high, but still certainly not sufficient to cause melting or severe softening of the steel." Aviation kerosene combustion typically results in large fires, but these fires do not have very high temperatures. This led Iga, FEMA and other researchers to believe that there was a weak point, and this point was identified as the floor anchorage to the building's supporting structure. Due to the fire, these fastenings became loose and, when they collapsed under the weight of the floor, collapse began. On the other hand, the NIST report states completely and unequivocally that these fasteners were not destroyed. Moreover, it was their strength that was one of the main reasons for the collapse, since through them a force was transmitted to the peripheral columns, bending the columns inward.

At temperatures above 400-500 °C there is a sharp decrease in the tensile strength and ductility limit (3-4 times), at 600 °C they are close to zero and the bearing capacity of the steel is exhausted.

NIST report

Organization of the study

As a result of mounting pressure from experts, construction industry leaders and family members following the release of the FEMA report, National Institute of Standards and Technology The Commerce Department's NIST conducted a three-year, $24 million investigation into the destruction and collapse of the World Trade Center towers. The research included a series of experiments, in addition, leading specialists from many third-party organizations were involved in it:

• Structural Engineering Institute of the American Society of Civil Engineers (SEI/ASCE)
• Society of Fire Protection Engineers (SFPE)
• National Fire Protection Association (NFPA)
• American Institute of Steel Construction (AISC)
• Council on Tall Buildings and Urban Habitat (CTBUH)
• Structural Engineers Association of New York (SEANY)

Scope of study and its limitations

The NIST study's scope was limited to examining the "sequence of events from the moment the aircraft was hit until the collapse of each tower began" and also included "a small analysis of the structural behavior of the tower structure once the conditions for its failure had been reached and collapse was imminent." Like many other engineers working on this issue, NIST experts focused on aircraft hits on turrets, simulating the effects of hits such as structural failure, fire spread, etc. in a very high degree of detail. NIST has developed several very high-detail models of various building components, such as floor-supporting lintels, and entire buildings have also been modeled, but at a lower level of detail. These models were static, or quasi-static, and included deformation simulations, but did not include simulations of the movement of structural elements after they were separated from each other. Thus, NIST models are useful for understanding why towers begin to collapse, but do not provide a way to model the collapse itself.

Parallel investigations

In 2003, three engineers from the University of Edinburgh published a report suggesting that the fires alone, even without taking into account the destructive effects of aircraft strikes, were enough to completely destroy the WTC towers. In their opinion, the design of the towers made them uniquely vulnerable to large fires covering several floors at once. When the NIST report was released, Barbara Lane and the English engineering company Arup criticized its conclusion that the destruction caused by aircraft hits was a necessary factor for the collapse of buildings .

Criticism

Some engineers have offered insight into how the towers collapse by developing animated collapse sequences based on dynamic computer models and comparing the resulting results with video footage of the disaster site. In October 2005, the magazine New Civil Engineer relative to a computer model created by NIST. In response, NIST enlisted Colin Bailey of the University of Manchester and Robert Planck of the University of Sheffield to create the computer visualizations needed to work to correct models of tower collapses and bring those models into full agreement with observed events.

Other buildings

Parts of the outer wall of the north tower opposite the remains of the 6 WTC building, which received very serious damage as a result of the fall of the north tower. In the upper right corner are the remains of the 7 WTC building.

On September 11, 2001, the entire World Trade Center complex and the small Greek Orthodox Church of St. Nicholas, which stood on Liberty Street opposite the south tower of the World Trade Center, were destroyed. In addition, many buildings surrounding the complex were damaged to one degree or another.

Consequences

Clearing the disaster site

The huge pile of rubble at the World Trade Center site continued to burn and smolder for another three months, with attempts to control the fire unsuccessful until a significant amount of debris and debris had been removed. The clearance was a very large-scale operation, coordinated by the Department of Construction (DDC). A preliminary clearing plan was prepared on September 22 by Controlled Demolition Inc. (CDI) from Phoenix. Mark Lozo, president of CDI, particularly emphasized the importance of protecting the clay wall (or "bathtub") that protected the WTC foundation from being flooded by the waters of the Hudson. The cleanup was carried out around the clock, involving a large number of contractors, and cost hundreds of millions of dollars. In early November, after about a third of the debris had been cleared, the city government began reducing the involvement of police and firefighters in the cleanup as they searched for the remains of the dead, and shifted priorities to trash removal. This caused objections from firefighters. As of 2007, demolition of some of the buildings surrounding the WTC was ongoing, while construction of the WTC replacement, memorial complex, and Freedom Tower continued.

Controlled demolition versions

There is a theory that the WTC towers could have been destroyed as a result of a planned, controlled demolition, and not as a result of being hit by aircraft. This theory was rejected by NIST, which concluded that no explosives were involved in the collapse of the towers. NIST stated that it did not perform tests to look for explosive residues of any kind in the debris because it was not necessary:

12. Did the NIST investigation look for evidence of the WTC towers being brought down by controlled demolition? Was the steel tested for explosives or thermite residues? The combination of thermite and sulfur (called thermate) "slices through steel like a hot knife through butter."

NIST did not test for the residue of these compounds in the steel.

The responses to questions number 2, 4, 5 and 11 demonstrate why NIST concluded that there were no explosives or controlled demolition involved in the collapses of the WTC towers.

In a 2008 report, NIST also analyzed the WTC Tower 7 explosion hypothesis and concluded that the explosion could not have caused the observed effects. In particular, the smallest amount of explosive that could destroy Column 79 would produce a noise of 130-140 decibels at a distance of 1 km from 7 WTC, but such noise was not noticed by either sound recording equipment or witnesses. This theory has become a prominent part of most of all the "conspiracy theories" that arose as a result of the events of September 11.

Notes

1. Relatives gather at ground zero to mark 9/11, The Associated Press/MSNBC(September 9, 2007). Retrieved November 3, 2007.
2. PartIIC - WTC 7 Collapse (pdf). NIST Response to the World Trade Center Disaster. National Institute of Standards and Technology (April 5, 2005). Archived from the original on March 4, 2012. Retrieved November 1, 2006.
3. Hamburger, Ronald, et al.(pdf). Federal Emergency Management Agency. Archived
4. Snell, Jack, S. Shyam Sunder NIST Response to the World Trade Center Disaster (pdf). National Institute of Standards and Technology (November 12, 2002). Archived from the original on March 4, 2012. Retrieved July 27, 2006.
5. Chapter 1 // . - NIST. - P. p. 6.
6. National Construction Safety Team Final Report on the Collapse of the World Trade Center Towers. - NIST.
7. Barrett, Devlin Steel type in WTC met standards, group says. The Boston Globe. Associated Press (2003). Retrieved May 2, 2006.
8. Glanz, James and Eric Lipton. The Height of Ambition (English) , The New York Times(8 September 2002).
9. Adam Long. PILOT LOST IN FOG; SCENE OF PLANE CRASH LAST NIGHT AIRPLANE CRASHES INTO SKYSCRAPER Ceiling Reduced by Fog, The New York Times(24 May 1946).
10. (pdf). NIST NCSTAR 1-1 Pages 70-71 Archived
11. Leslie E. Robertson. Reflections on the World Trade Center (English) // The Bridge. - National Academy of Engineering, 2002. - Vol. 32. - No. 1. Archived from the original on February 28, 2010.
12. Fahim Sadek. NIST NCSTAR 1-2. Baseline Structural Performance and Aircraft Impact Damage Analysis of the World Trade Center Towers. - NIST, September 2005. - pp. 3-5, 308.
13. Nalder, Eric. (English) The Seattle Times (27-02-1993).
14. Ronald Hamburger, et al. World Trade Center Building Performance Study. - Federal Emergency Management Agency. - P. 1-17.
15. NIST's Working Hypothesis for Collapse of the WTC Towers (Appendix Q). NIST (June 2004). Archived from the original on March 4, 2012. Retrieved December 21, 2007.
16. NIST was informed by the Port Authority that the documents cited were destroyed in the collapse of WTC 1 and the WTC owners documents held in WTC 7 were also lost.
17. Lew, H. S.; Richard W. Bukowski and Nicholas J. Carino Design, Construction and Maintenance of Structural and Life Safety (pdf). NIST NCSTAR 1-1 Page 71. National Institutes of Standards and Technology (2006). Archived from the original on March 4, 2012. Retrieved October 15, 2007.
18. Jane's All the World's Aircraft Boeing 767. Jane's (2001). Retrieved August 19, 2007.
19. Field, Andy A Look Inside a Radical New Theory of the WTC Collapse. Fire/Rescue News (2004). Retrieved July 28, 2006.
20. Gross, John L., Therese P. McAllister Structural Fire Response and Probable Collapse Sequence of the World Trade Center Towers (pdf). Federal Building and Fire Safety Investigation of the World Trade Center Disaster NIST NCSTAR 1-6 Archived
21. Wilkinson, Tim World Trade Center - Some Engineering Aspects (2006). Archived from the original on March 4, 2012. Retrieved July 28, 2006.
22. Lawson, J. Randall, Robert L. Vettori. NIST NCSTAR 1-8 - The Emergency Response P. 37. NIST (September 2005). Archived from the original on March 4, 2012.
23. McKinsey Report - Emergency Medical Service response. FDNY/McKinsey & Company (August 9, 2002). Archived from the original on August 26, 2011. Retrieved July 12, 2007.
24. McKinsey Report - NYPD (August 19, 2002). (inaccessible link - story) Retrieved July 10, 2007.
25. NY Firefighters attack Giuliani. BBC News, July 12, 2007 http://news.bbc.co.uk/2/hi/americas/6294198.stm
26. Bažant, Zdeněk P.; Yong Zhou (2002-01-01). "Why Did the World Trade Center Collapse? - Simple Analysis". J Engrg Mech 128 (1): pp. 2-6. DOI:0.1061/(ASCE)0733-9399(2002)128:1(2) . Retrieved 2007-08-23.
27. Bažant, Zdeněk P.; Mathieu Verdure (March 2007). "Mechanics of Progressive Collapse: Learning from the World Trade Center and Building Demolitions." J Engrg. Mech. 133 (3): pp. 308-319. DOI:10.1061/(ASCE)0733-9399(2007)133:3(308) . Retrieved 2007-08-22.
28. Cherepanov, G.P. (September 2006). "Mechanics of the WTC collapse". Int J Fract(Springer Netherlands) 141 (1-2): 287-289. DOI:10.1007/s10704-006-0081-8. Retrieved 2007-10-07.
29. Hayden, Peter WTC: This Is Their Story. Firehouse Magazine (April 2002). (inaccessible link - story)
30. Observations, findings and Recommendations (pdf). World Trade Center Building Performance Study, (Chapter 8.2.5.1). Federal Emergency Management Agency. Archived from the original on March 4, 2012. Retrieved July 28, 2006.
31. Barnett, J.R.; R.R. Biederman, R.D. Sisson Jr. An Initial Microstructural Analysis of A36 Steel from WTC Building 7. Feature: Letter. The Journal of Materials (2001). Archived from the original on March 4, 2012. Retrieved May 12, 2006.
32. Key Findings of NIST's June 2004 Progress Report on the Federal Building and Fire Safety Investigation of the World Trade Center Disaster. Fact sheets from NIST. National Institute of Standards and Technology (2004). Archived from the original on March 4, 2012. Retrieved July 28, 2006.
33. Interim Report on WTC 7 (pdf). Appendix L. National Institute of Standards and Technology (2004). Archived from the original on March 4, 2012. Retrieved July 28, 2006.
34. NIST Releases Final WTC 7 Investigation Report. National Institute of Standards and Technology (November 20, 2008). Archived from the original on March 4, 2012. Retrieved August 28, 2009.
35. Robert MacNeill, Steven Kirkpatrick, Brian Peterson, Robert Bocchieri. Global Structural Analysis of the Response of World Trade Center Building 7 to Fires and Debris Impact Damage. - November 2008. - pp. 119-120.
36. Questions and Answers about the NIST WTC 7 Investigation. National Institute of Standards and Technology (21 April 2009). Archived from the original on March 1, 2010.
37. Barrett Wayne Grand Illusion: The Untold Story of Rudy Giuliani and 9/11. - Harper Collins. - ISBN 0-06-053660-8
38. Replying to Giuliani
39. Oliver, Anthony Lasting lessons of WTC. New Civil Engineer (June 30, 2005). (inaccessible link - story) Retrieved July 28, 2006.
40. Whitehouse, David WTC collapse forces skyscraper rethink. BBC News (2001). Archived from the original on March 4, 2012. Retrieved July 28, 2006.
41. Snell, Jack. "The Proposed National Construction Safety Team Act." NIST Building and Fire Research Laboratory. 2002.
42. Experts Debate Future of the Skyscraper in Wake of Disaster, Engineering News-Record(September 24, 2001).
43. Glanz, James and Eric Lipton. “Nation Challenged: The Towers; Experts Urging Broader Inquiry In Towers" Fall". New York Times December 25,
44. Dwyer, Jim. "Investigating 9/11: An Unimaginable Calamity, Still Largely Unexamined." New York Times. September 11,
45. NIST. "NIST's Responsibilities Under the National Construction Safety Team Act"
46. Thomas Egar. The Collapse: An Engineer's Perspective. Nova (2002). (inaccessible link - story) Retrieved July 28, 2006.
47. Eagar, Thomas W.; Christopher Musso (2001). Why Did the World Trade Center Collapse? Science, Engineering, and Speculation. JOM, 53(12). The Minerals, Metals & Materials Society. Retrieved on 2006-05-02.
48. Clifton, G. Charles Collapse of the World Trade Center Towers (pdf) (2002). (inaccessible link - story) Retrieved July 28, 2006.

World news

11.09.2016

The eleventh day of September 2001 went down in history as a tragedy on a global scale, dealing a crushing blow to the faith of citizens of a democratic community in their own safety and integrity. Terrorist attack of September 11, 2001 killed 2 thousand 752 people

The most important signs of demolition work at the World Trade Center

The rapid and strictly vertical collapse of skyscrapers (this happens when a building is targeted for demolition), despite the fact that the “twins” collapsed vertically, the third building was also completely razed to the ground - WTC#7, which was not rammed by planes, all structures were practically destroyed " into crumbs" (this effect is achieved only with professional explosive dismantling), experts heard on the recordings the sounds of several explosions seconds before the collapse, which came from the first floors, captured on many amateur videos, wisps of smoke and flashes almost forty floors below the level where the planes crashed , numerous fragments of glass, steel and human remains found over a very wide radius, including on the roofs of houses, many vertical supporting beams were cut diagonally (such a preparatory procedure is also typical for dismantling), remains of combustion of the Thermate substance, usually used for military purposes for thermal cutting of steel (discovered at the site of the rubble by independent experts), numerous traces of steel supporting structures melted to a lava-like state. The combustion continued even on the fifth or sixth day and was recorded on NASA aerial photographs (airplane kerosene is not capable of creating such high temperatures - a minimum of 1500oC is required!).

The names of specialists who disagree with the official White House version are impressive - leading scientists in the fields of history, defense, psychology, philosophy and applied sciences. Conducted research confirms the opinion that the World Trade Center buildings in New York were destroyed by controlled explosions, and the authorities' version of the Pentagon attack does not stand up to criticism. Scientists are convinced that the government not only allowed the September 11 attacks to occur, but also staged them for political purposes.


The names of the people who made sensational accusations are striking:
Robert M. Bowman is the former director of Project Star Wars, the US Air Force space defense program (101 combat missions).

Fred Burks is a translator for many American presidents and people who are familiar with the political cuisine of America first-hand.

Lloyd de Moos is director of the Institute of Psychohistory, president of the International Psychohistorical Association and editor of the Journal of Psychohistory.

Eric Douglas is a New York architect, chairman of the independent committee reviewing projects for the restoration of the World Trade Center.

James Fetzer is a renowned scientist, professor at McKnight University (Minnesota), former US Marine Corps officer, author and editor of more than 20 academic publications, co-founder of the S9/11T group.

Robert Fritzius - electronic engineering, radar and telecommunications specialist.

Daniel Ganser is a historian, representative of the University of Basel (Switzerland).

Michael Gass - explosives specialist (US Air Force), sapper, author of mine clearance techniques.

Kenyon Gibson is a former naval intelligence officer and the author of several books on the events of 9/11.

Rich Hellner - air traffic control, dispatcher.

Don Jacobs is the former Dean of the School of Education and Professor of Education at Northern Arizona University.

Andrew Johnson is a physicist, computer scientist, and software developer.

Stephen Jones is a physics professor, co-founder of the S9/11T group, and creator of the website.

Peter Kirsch is a renowned pathologist.

Wayne Madsen is a investigative journalist and former intelligence officer.

Richard McGinn is professor of linguistics, Ohio University.

Morgan Reynolds is a professor of economics, a leading economist at the Department of Labor during the George H. W. Bush administration, and director of the criminal justice center at the National Center for Policy Analysis.

E. Martin Schotz - historian, psychiatrist, mathematician.

Glenn Stanish is a pilot and director of the Airline Pilots Association.

Andreas von Bülow - ex-Deputy Minister of Foreign Affairs of Germany, head of the German intelligence services, member of parliament for 25 years.

Jonathan Wilson is a specialist in criminology, University of Winnipeg (Canada).

This is far from full list, allowing you to get an idea of ​​the level of professionalism of the people who made accusations against the American government. What gives them the right to question the official White House narrative? The answer to this question can be found on the website www.st911.org, where 20 reasons for distrust of President Bush are published.

The 9/11 Commission refused to review vast amounts of testimony and evidence. Even the former director of the FBI stated that the mentioned commission was keeping silent real events.
The recording of the interrogations of the dispatchers on duty on September 11 was deliberately destroyed - the tapes were broken by hand, the film was torn into small fragments, and its fragments were thrown into various trash cans.
Congressional investigators discovered that an FBI informant provided housing for two hijackers in 2000. When the commission wanted to question this citizen, the FBI not only refused to comply with this request, but also hid the informant. According to some reports, the FBI took such steps after receiving appropriate instructions from the White House.
A retired U.S. Air Force lieutenant colonel and former director of the Star Wars project recently issued the following statement: “If our government had done nothing that day except to ensure that the normal procedure required in such cases was followed, the Twin Towers would still be standing. thousands of dead Americans would still be alive. Our government's actions are treason!


Recently declassified documents show that in the 60s, the American high command developed a plan to blow up AMERICAN aircraft and commit terrorist attacks against US citizens on American soil.

The US Defense Department, responsible for the safety of citizens, has been conducting exercises for many years, developing a version of using kamikaze aircraft against the World Trade Center buildings and other American skyscrapers. “Various types of civil and military aircraft were used to practice actions in the event of a possible terrorist attack. In other words, the Pentagon used REAL EXISTING AIRCRAFT to simulate an attack on high-rise buildings, including the Twin Towers. Why did the department “turn out to be unprepared” - remains a question.
In addition, the military was practicing options for similar attacks on the Pentagon.
On the morning of September 11, American defense and intelligence agencies conducted military exercises to combat terrorism using REAL aircraft and fake "radar tags", which misled the controllers.
It was on the morning of September 11 that the government conducted maneuvers simulating a terrorist air attack on the World Trade Center.
Despite the government's claims of ignorance of the terrorist plane, the US Secretary of Transportation testified to the commission that Vice President Cheney personally monitored the pilots of the ill-fated Flight 77 many miles before the vehicle approached the Pentagon.
The third building of the World Trade Center (building No. 7) collapsed on September 11, despite the fact that it was not hit by terrorist planes. It collapsed as if it had no walls or ceilings. Before the tragedy, only small local fires were noted in the building. It is the only steel frame building in the world to be destroyed by fire, which by definition cannot happen.
According to a number of FBI employees, the World Trade Center buildings collapsed as a result of the explosion of bombs planted inside it.
MSNBC claims that police believed that one of the explosions at the World Trade Center could have been caused by a truck full of explosives located inside the building. In their opinion, explosive devices could have been placed both in the building itself and in its immediate vicinity.
The explosions may have been caused by "bombs" and "secondary devices," according to the New York City Fire Department's safety chief. Firefighters believed there were bombs in the building.
A spokesman for the National Demolition Association said the collapse of the Twin Towers resembled a "classically planned demolition of a building."
Eyewitnesses of the explosion claim that the explosions occurred much BELOW the area hit by the planes. Moreover, they happened BEFORE the first plane hit the building.
According to the testimony of a certain police officer, destructive explosions on the upper floors occurred at intervals of 15 minutes. The building collapsed only after that.

Scientists managed to collect and systematize dozens of facts that were “overlooked” by the authorities, distorted their essence, or (what is especially scary) did not find a place on the pages of official reports. Every aspect of the official version raises doubts among the inquisitive and literate reader who wants to know the truth about what happened.

Terrorist attack or controlled explosion?


According to representatives of science, "the fire (fire) could not lead to the destruction of the steel structures of the building." Supporters of the official (government) version of the tragic events keep silent about this fact. Moreover, according to a report signed by the Directorate of the National Institute of Standards and Technology (2005), the steel structures of the buildings were destroyed allegedly as a result of fires. At the same time, science does not know a single similar fact.

Interestingly, the towers were designed with the possibility of air attack in mind and were built with the design strength to withstand a collision with such a colossus as a Boeing 767.

"They were designed to withstand all sorts of impacts, including tornadoes, bombings or collisions with huge airliners," says Hyman Brown, project manager for the Twin Towers (2001).

The theory about the destruction of the building as a result of fire and melting of the supporting steel structures is also absurd. According to experts, the destruction of skyscrapers is reminiscent of a “controlled detonation,” when a certain amount of explosives is placed in supporting structures and triggered in the desired sequence.

During a controlled detonation, the destruction of a building occurs suddenly - at first there is nothing, but the next moment the structure disintegrates. The steel structure at high temperature cannot suddenly break. This happens gradually - the horizontal beams begin to sag, and then the vertical steel columns become deformed.

But the video recording of the destruction of the towers did not record similar processes even on the floors located above the hole left by the plane. In addition, the art of controlled detonation of a high-rise building is to ensure that the exploded skyscraper does not fly apart in all directions, but “sags” in such a way that the debris remains exclusively at the construction site. This is what happened with the towers.

According to Marc Loisier, president of a major controlled detonation company, such an explosion "must be completely planned, and the explosives must be placed in a certain order." All 110 floors of the twin towers collapsed very neatly. In case of an unplanned explosion construction waste would have covered the entire area, but this did not happen.

In a controlled detonation, the remains of a building fall to the surface at free fall speed, which does not happen in a random disaster. To do this, demolitionists first place explosives under the support systems of the lower floors, so the upper ones fall down, meeting virtually no resistance.

According to the commission's report, the south tower collapsed in 10 seconds, which corresponds to a controlled explosion. Moreover, this technique makes it possible to “cut” load-bearing steel structures into pieces of a certain length, which was recorded in New York. The huge cloud of dust that formed at the site of the towers after the explosion also serves as indirect evidence of a controlled explosion. Colonel John O'Dowd of the US Army Corps of Engineers came to this conclusion. “It seemed that the air at the site of the World Trade Center explosion was saturated with cement dust.”

Another proof of a planned explosion is a huge amount of molten steel at the site of the collapse of the towers. Thus, Peter Tully, head of the construction company Tully Construction, and Mark Loisier reported on “lakes of molten steel” discovered at the site of collapsed buildings in underground elevator shafts. Meanwhile, the collision of the plane with the building and the subsequent ignition of aviation fuel could not lead to the formation of temperatures at which steel structures begin to melt. The mystery of the explosion of the Twin Towers, according to scientists, still remains unsolved. What about the government? It remains inactive, refusing to divulge information that contradicts the official theory.

Shortly after the events of September 11, more than 500 New York City fire and ambulance personnel gave oral testimony pointing out some of the inconsistencies noted during the response to the terrorist attack. The New York City mayor's office did everything possible not to make these facts public or to refute them.

Only in August 2005, The New York Times and a group of relatives of the victims, as a result of a lengthy trial and a number of appeals, managed to force the mayor's office to publish the mentioned testimonies of direct witnesses to the death of the WTC.

Witness accounts refute government theories, proving that the events of 9/11 were a well-planned terror attack.

Unfortunately, American officials do not want to conduct an independent investigation, establish the truth and punish those responsible. Why is this happening? Who benefits from this and why? These questions remain unanswered, but the public is not satisfied with the Bush administration's position, and the S9/11T group does not intend to stop its activities. Soon we will expect new details that will reveal the essence of these tragic events and the hypocrisy of officials. If the statements of American scientists turn out to be true, “controlled detonation” may well lead to an uncontrollable reaction from society - not only the American one, but also the world one. And then the authors of the biggest hoax in the history of mankind may not be in trouble, writes Konstantin VASYLKEVICH

THE BEHAVIOR OF THE US SECURITY SERVICES PROVES IMPOSSIBLY THAT THE 9/11 TERROR ATTACKS IN THE USA ARE THEIR HANDS.

In their haste to blame Muslims for this, in their haste to strike at Afghanistan, they made an investigation against the intelligence services themselves impossible.

“The US government announced the creation of a new structure within its intelligence services (numbering 170,000 people with an annual budget of $37 billion), designed to coordinate the efforts of different departments, as well as for the extrajudicial physical destruction of terrorists around the world, that is, to kill individuals undesirable to the “world behind the scenes” (previously, the CIA hid such operations, now there is no need for this: it is enough to declare someone a “terrorist”). This was a new step in the global war “against terrorism,” declared after the terrorist attacks of September 11, 2001, which gave the United States a free hand to forcefully subjugate the entire planet. Even then, many democratic countries adopted laws facilitating surveillance, preventive arrests, electronic wiretapping, and the abolition of the secrecy of bank deposits; Measures of political censorship were introduced in democratic media, including the closure of sites on the Internet that “distribute hate propaganda.” That is, the extrajudicial repressions of the special services against their own citizens were significantly expanded.” "TOMORROW", N30, 2002."

The BUSH administration used the Boeing attack as a pretext for invading Iraq and Afghanistan in order to realize its dream of world hegemony under the banner of the fight against terrorism.

Construction of the North Tower was completed in 1971, and two years later the South Tower was also commissioned. The official opening date of the World Trade Center in New York is April 4, 1973.
Characteristics of the World Trade Center Towers:
As a result, the twin towers became the tallest skyscrapers in the United States. Each “giant brother” had 110 floors. The height of the 1st WTC building was 526.3 meters including the antenna. The last floor in the South Tower rose 411 m from the ground, and in the North Tower - 413! The depth of the foundation was 23 meters underground. The length of power cables exceeded 5,000 kilometers, and the total power electrical network amounted to about 80,000 kW. Thus, the builders really managed to bring to life the “Project of the Century,” which became one of the symbols of the United States, the pride of the American people. In the last years of the Complex's existence, about 50,000 people came to work at the World Trade Center every day, and another 200,000 people a week visited the World Trade Center as tourists. An Observatory was established in the South Tower on the 107th floor. The observation deck offered a magnificent view of the city. In the North Tower, on the level between the 106th and 107th floors, there was a chic restaurant “Windows on the World”, which was opened in 1976 and was the “highest” food outlet in the world. At that time, no one could have imagined that these towers would ever fall. After all, the frame of the building, according to engineers, could withstand a blow of colossal force, for example, when rammed by an airplane. Moreover, the towers were not afraid of the strongest gusts of wind that raged at an altitude of 400 meters. The design of the skyscrapers was highly durable and stable, thanks to facades made in the form of steel frames and aluminum modular sections built into them. These elements measured 10x3.5 meters. All technical tricks were in vain, since when the planes crashed, it was not the destructive force of the collision that played a decisive role, but the high temperature. As a result of the explosion of fuel tanks containing over 5000 liters of gasoline, the steel was instantly heated to 1000 degrees Celsius! This is what triggered the collapse.

Destruction of the World Trade Center.

Evidence of explosives in the Twin Towers.

Millions of people around the world watched the events around the World Trade Center in live CNN on September 11, 2001 and could hardly believe their eyes. They saw huge plumes of smoke over Manhattan and saw the towers collapse... in a strange way. They didn't fall apart; they are "FOLDED" in a way that many have seen in CONTROLLED DEMOLITION: the building does not collapse chaotically, scattering debris over a wide area; rather, it collapses on itself. This is exactly how the World Trade Center towers collapsed.
That the destruction of the towers was controlled was immediately noticed by some astute observers:
Well, is it just me, or has anyone else realized that it wasn't plane attacks that destroyed the World Trade Center? For me personally, this is the most frightening moment of this morning. ...
If you look at the timing, you will see that everything happened as follows:
- The plane crashes into the 1st tower, making a hole in the very top part. Then quite expected things happen:
- The tower remains standing. The reinforced concrete building is *extremely* strong. Terrorists have already detonated a large bomb *inside* this same building without much damage. ...

The second plane crashes into the second tower, lower and at higher speed. He punches a larger hole in it, and debris rains down on the streets, but the building nevertheless stands and looks quite solid.
- The second building begins to burn, also up from the collision site.
- About half an hour later, the fire in the first building *goes out*. It is still smoldering and black smoke is coming out, but there is no flame. ...
- The fire in the second building went out.
- The second building suddenly crumbles into dust, as if a smooth wave ran from above the building (above the place of combustion) down through all floors at the same speed. The debris predominantly falls inward. Individual solid pieces do not fall off the building and do not collapse on the surrounding buildings. ... The destruction started from the top (above the collision site). It happens evenly. All structural elements are destroyed sequentially, so that no load-bearing skeleton remains. The destruction is uniform, symmetrical and absolute.
To sum it up: this all looks like demolition - because that's what it is.
- The first tower collapses as a result of a similar “wave”.
There is no doubt that the planes that crashed into the towers caused serious damage. But look at the photographs - these buildings were simply *razed to the ground*. Demolition of a building does not require a lot of explosives, but they must be placed in the right places (in direct contact with structural elements) and detonated in an even, synchronized sequence. ...
This message appeared on the Internet on September 11th, a few hours after the destruction of the Twin Towers. From the very beginning, some people were not deceived.

There was a problem with the explosives theory at first: there were no media reports that anyone heard explosions immediately before the World Trade Center collapsed. But for last year Such reports have appeared, and there is even video footage in the public domain showing that there were actually explosions inside the Twin Towers before they collapsed.
Television viewers watching the horrific events of September 11th saw explosions before the towers collapsed. Television images show what appears to be a large explosion close to ground level near the 47-story Salomon Brothers building, known as WTC 7, before the first tower collapsed.
... One witness, whose office is near the World Trade Center, told AFP that he was standing in the crowd on Church Street, about two and a half blocks from the South Tower, when he saw "a series of short flashes coming from inside the building between 10 and 15 floors." He saw about 6 of these short flashes accompanied by a "crack" before the tower collapsed. Each tower had six load-bearing columns.
One of the first firefighters in the second tower attacked, Louie Cacchioli, 51, told People Weekly on September 24: "I was taking firefighters in the elevator to the 24th floor to evacuate employees. During the last lift, a bomb exploded. We believe that bombs were planted in the building."
Kim White, 32, an employee on the 80th floor, also reported hearing an explosion. "Suddenly the whole building shook, then started swaying. We didn't know what was happening," she told People. "We gathered all the people from the floor to the stairwells... at that time we all thought it was a fire... We went down to the 74th floor... then there was another explosion."
(Many testimonies insist on the presence of bombs at the WTC collapse).
A Danish website offers a 4-hour video containing evidence of what happened on September 11th and what was suppressed or ignored by the mainstream media:
Video clips of falling Towers were often edited in ways that prevented viewers from getting the "full picture" of the entire collapse of the towers. ... During my 1000 hours of video investigation, I found very few "full-length, long-range images" that showed the towers in their entirety (top to bottom). Most of the video clips we have seen about 9/11 (and in the weeks since) are edited versions...[which] completely fail to show the numerous "clouds" from EXPLODING bombs "burst out of the windows" of the World Trade Center façade well below the impact site. ... Some people in the “editorial room” did not want to show us the “Full Picture”!
But some of the most important video evidence of the BOMB remains! In my video I will show you 5 significant "CLOWS OF DUST" from destructive bombs exploding INSIDE the World Trade Center Towers. These "bomb clouds" were located approximately 20 and 40 levels BELOW the "impact level" of the falling towers. ... They provide complete proof of the presence of Bombs of Destruction, detonated WAY BELOW the "impact point level."
("Bombs Inside the World Trade Center").
________________________________________
The WebFairy 911 Memorial website has some very interesting videos. Particularly interesting is the clear evidence of explosions that occurred during the fall of the North Tower.
The left photo is footage of a controlled demolition: note what WebFairy calls "demolition firecrackers," the clouds of debris and dust that are thrown horizontally by the detonation of charges placed at multiple levels in the building that will be demolished.
Now look at the photo on the right: this is footage of the collapse of the North Tower. Two horizontal bursts from the explosions are clearly visible before the debris reaches the bottom of the frame.
________________________________________

But it wasn't just the Twin Towers that were deliberately destroyed, but also the building known as WTC 7.
"Unquoted by the monopolized press, some firefighters who survived Black Tuesday insist that there were explosions in the buildings, in parts of the twin towers of the World Trade Center, separately and away from the impact of the planes crashing into the buildings. ... Were explosives detonated inside the buildings remotely to demolish the towers, as they do with old buildings? And there is good reason to believe that the explosives inside caused the mysterious collapse, already on the evening of Black Tuesday, of Building 7 of the World Trade Center complex.
(Sherman H. Skolnick: "The Overthrow of the American Republic", Part 14).
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The Twin Towers collapsed in a very strange manner, leaving virtually nothing but metal fragments of the outer wall and a huge amount of fine ash and dust, with no central steel columns of the lower sixty floors standing or fallen. This is very strange. Look at all that dust (click on the picture to enlarge it, and also see the next two photos of the dust clouds). It was as if some kind of high-energy destruction beam was focused on the towers, pulverizing each concrete block into tiny particles of ash and dust.
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But while some form of dark technology may have been used to bring down the Twin Towers, we don't need to prove it, since the fall could well be explained by a controlled demolition using explosives. In fact (as Christopher Bollyn first pointed out in his Open Letter), evidence of large explosions was recorded by seismographs located 34 km from the WTC:

“A sharp peak of short duration” - this is what an underground nuclear explosion looks like on a seismograph.
The seismograph that recorded this data worked at Columbia University's Lamont-Doherty Earth Observatory. The American Geophysical Union published a report in the November 20th issue of Eos, but the authors misinterpreted the data. They speculated and reported that the two largest signals were caused by the fall of the Twin Towers. But:
"During the collapse, most of the energy from the falling pieces was absorbed by the towers and surrounding structures, transforming them into debris and dust, or causing other damage - but without producing significant ground shaking."
(Dr. Arthur Lerner-Lam, director of Columbia University's Center for Hazards and Risk Research, as quoted in Earth Institute News).
So, if most of the energy from the falling debris was dissipated and did not cause the major peaks in the seismic record, then what was it? Perhaps large explosions at the lowest levels (minus 7th level) of the Twin Towers' foundation, near the load-bearing steel columns where they rested on the rock of Manhattan? Maybe even small NUCLEAR explosions?
This, together with numerous small explosions at every tenth or so level of the load-bearing steel columns, may explain an observation that the official version does not explain: why did the lower part of the massive steel support columns not remain standing after the collapse? If the official story is correct that the destruction was the result of collisions and fire, which occurred only on the upper floors, and that the floors then "settled" on top of each other, one would expect steel columns at the core of, say, the 20 or 30 lower floors , should have remained standing, which did not happen. But this becomes understandable if the bases of the steel columns were destroyed by explosions at the rock level. With the base destroyed and supporting steel columns broken by explosions on different levels Twin Towers, the upper floors lost their support and collapsed to ground level in about ten seconds.
Further evidence of the presence of explosives comes from video footage of the collapse of the South Tower, with approximately 30 of the top floors tilting as the collapse began. If the floors were "sat" on top of each other, as the official version claims, then these upper floors should have fallen straight down. But if explosions somewhere near the impact level broke the steel supporting columns in the center, then it is clear why the upper floors tilted (possibly towards the damaged corner where the plane crashed).
Explosive devices could be enclosed in a heat-resistant shell to prevent them from exploding in a fire. If synchronicity was important, then they could be detonated remotely (by radio or microwave signal) at the right time. Even if the fire disabled the bombs at the plane impact level, it would not be able to damage the bombs below the fire level. No wires, processors or clockworks are needed, just a way to trigger each device with a unique signal. Even a synchronized sequence might not be necessary - the simultaneous explosion of all devices at ground level might be sufficient to achieve the desired result.
The time t required for an object to fall from a height h (in vacuum) is calculated by the formula t = sqrt(2h/g), where g is the acceleration of gravity. Thus, an object falling from the top of one of the towers (using h = 1306 feet (398 meters) and g = 32.174 feet/sec2 (9.81 meters/sec2)) would take 9.01 seconds to hit the ground, if we neglect air resistance and a few seconds longer if we take into account air resistance. The Twin Towers collapsed in 10 - 15 seconds, which is close to free fall. Immediately after the destruction began, the upper floors would have shattered the steel lintels in all 85 or so floors of the lower levels. Even if it took a second per floor, the collapse would have taken more than a minute. But material from the upper floors collapsed onto the lower floors at a rate of at least six floors per second. This is only possible if all structural elements of the lower 85 floors were completely destroyed before the collapse began. Since the lower floors were not damaged by the aircraft impact and fire, the removal of structural support on these floors must have occurred for another reason - and the most obvious possibility is explosives. That. the speed of collapse (not much faster than the speed of free fall) is strong evidence that the Twin Towers were destroyed during a controlled demolition using explosives (or other destructive technology) at all levels.
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For a week after the collapse of the Twin Towers, there were areas below the surface that remained extremely hot.
"AVIRIS data acquired on September 16, 2001, detected a number of thermally hot spots at the site of the World Trade Center collapse. Analysis of the data found temperatures above 800oF (430oC) at these locations (some over 1300oF (700oC))."
("American Geological Observations Report").
What was the source of this heat? Maybe residual effects from underground nuclear explosions?

A way to prove that the supporting steel columns of the Twin Towers were destroyed by explosives would be to examine their debris for what metallurgists call "twinning." But the WTC rubble was cleared as quickly as possible, and no investigative study of the rubble was allowed by the FBI or other government agency. Almost all of the 300,000 tons of steel from the Twin Towers were sold to New York scrap metal dealers and exported to places like China and Korea as quickly as ships could be loaded, thus destroying evidence. See "The Mountain of Debris Begins to Shrink," which shows that Controlled Demolition Inc. (a world leader in the demolition of high-rise buildings) apparently took good care to ensure that the rubble was removed and disposed of as quickly as possible, and was able to provide a detailed plan for these activities 11 days after the destruction of the Twin Towers, which suggests that this company has detailed information about the Towers. Gemini and the entire World Trade Center complex before 9/11.
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One could argue that the World Trade Center had hundreds of security guards and hundreds of surveillance cameras (possibly). With such a security force, it would be possible to plant a couple of bombs, but planting many of them (especially powerful enough to destroy the bases of load-bearing steel columns) seems impracticable. However, the World Trade Center changed hands 11 weeks before the attack. The new owner is Larry Silverstein. The destruction of the WTC and George W. Bush's declaration of the "War on Terrorism" turned out (and could have been predicted) to be extremely beneficial to Israel in its brutal suppression of the Palestinian people, in its efforts to destroy the Palestinian leadership, called "terrorist", and in its attempts to dominate all Arab neighbors . The new owners of the World Trade Center could easily be persuaded to cooperate in a plan with such obvious benefits for Israel. But if 11 weeks is considered insufficient time to plant explosives, then what about several years?

Terrorist attack or controlled explosion?
According to representatives of science, "the fire (fire) could not lead to the destruction of the steel structures of the building." Supporters of the official (government) version of the tragic events keep silent about this fact. Moreover, according to a report signed by the Directorate of the National Institute of Standards and Technology (2005), the steel structures of the buildings were destroyed allegedly as a result of fires. At the same time, science does not know a single similar fact.
Interestingly, the towers were designed with the possibility of air attack in mind and were built with the design strength to withstand a collision with such a colossus as a Boeing 767.
"They were designed to withstand all sorts of impacts, including tornadoes, bombings or collisions with huge airliners," says Hyman Brown, project manager for the Twin Towers (2001).
The theory about the destruction of the building as a result of fire and melting of the supporting steel structures is also absurd. According to experts, the destruction of skyscrapers is reminiscent of a “controlled detonation,” when a certain amount of explosives is placed in supporting structures and triggered in the desired sequence.
During a controlled detonation, the destruction of a building occurs suddenly - at first there is nothing, but the next moment the structure disintegrates. The steel structure at high temperature cannot suddenly break. This happens gradually - the horizontal beams begin to sag, and then the vertical steel columns become deformed.
But the video recording of the destruction of the towers did not record similar processes even on the floors located above the hole left by the plane. In addition, the art of controlled detonation of a high-rise building is to ensure that the exploded skyscraper does not fly apart in all directions, but “sags” in such a way that the debris remains exclusively at the construction site. This is what happened with the towers.
According to Marc Loisier, president of a major controlled detonation company, such an explosion "must be completely planned, and the explosives must be placed in a certain order." All 110 floors of the twin towers collapsed very neatly. In an unplanned explosion, construction debris would have covered the entire area, but this did not happen.
In a controlled detonation, the remains of a building fall to the surface at free fall speed, which does not happen in a random disaster. To do this, demolitionists first place explosives under the support systems of the lower floors, so the upper ones fall down, meeting virtually no resistance.
According to the commission's report, the south tower collapsed in 10 seconds, which corresponds to a controlled explosion. Moreover, this technique makes it possible to “cut” load-bearing steel structures into pieces of a certain length, which was recorded in New York. The huge cloud of dust that formed at the site of the towers after the explosion also serves as indirect evidence of a controlled explosion. Colonel John O'Dowd of the US Army Corps of Engineers came to this conclusion. “It seemed that the air at the site of the World Trade Center explosion was saturated with cement dust.”
Another proof of a planned explosion is a huge amount of molten steel at the site of the collapse of the towers. Thus, Peter Tully, head of the construction company Tully Construction, and Mark Loisier reported on “lakes of molten steel” discovered at the site of collapsed buildings in underground elevator shafts. Meanwhile, the collision of the plane with the building and the subsequent ignition of aviation fuel could not lead to the formation of temperatures at which steel structures begin to melt. The mystery of the explosion of the Twin Towers, according to scientists, still remains unsolved. What about the government? It remains inactive, refusing to divulge information that contradicts the official theory.
Shortly after the events of September 11, more than 500 New York City fire and ambulance personnel gave oral testimony pointing out some of the inconsistencies noted during the response to the terrorist attack. The New York City mayor's office did everything possible not to make these facts public or to refute them.
Only in August 2005, The New York Times and a group of relatives of the victims, as a result of a lengthy trial and a number of appeals, managed to force the mayor's office to publish the mentioned testimonies of direct witnesses to the death of the WTC.
Witness accounts refute government theories, proving that the events of 9/11 were a well-planned terror attack.

Unfortunately, American officials do not want to conduct an independent investigation, establish the truth and punish those responsible. Why is this happening? Who benefits from this and why? These questions remain unanswered, but the public is not satisfied with the Bush administration's position, and the S9/11T group does not intend to stop its activities. Soon we will expect new details that will reveal the essence of these tragic events and the hypocrisy of officials. If the statements of American scientists turn out to be true, “controlled detonation” may well lead to an uncontrollable reaction from society - not only the American one, but also the world one. And then the authors of the biggest hoax in the history of mankind may be in trouble.

Reference.
Currently, on the site of the twin towers, construction is underway of three new skyscrapers, under the working names Tower No. 2, No. 3 and No. 4, and a tower 541 meters high, which received the symbolic name “Freedom Tower”. All new buildings will be strikingly different from the first towers that fell in the terrorist attack. The groundbreaking ceremony for the new World Trade Center was held in July 2004, and construction itself began on April 27, 2006. The site is being developed by Larry Silverstein, a real estate entrepreneur. According to the plan, the completion of the Freedom Tower should take place before 2013. In addition to this tower, the new World Trade Center in New York will also include a residential skyscraper, three high-rise office buildings, a museum and memorial to the victims of the tragedy of September 11, 2001, as well as a concert and exhibition center. Many Americans dubbed the 540-meter skyscraper the “Tower of Fear” because... During its construction, innovative technologies will be used to prevent destruction in the event of a terrorist attack of any force. In particular, it is planned to encase the first 52 meters of the building in a concrete frame, and use prismatic glass for the exterior decoration; this is the only way to avoid the notorious “stone bag” visual effect.

In the United States, suicide bombers from the terrorist organization Al-Qaeda hijacked four passenger planes, sending two of them to the symbol of business New York - the World Trade Center towers, and the other two - to the Pentagon and, presumably, the White House or the Capitol. All aircraft except the last one reached their targets. The fourth hijacked plane crashed into a field near Shanksville, Pennsylvania.

New York District Judge George Daniels issued a default judgment ordering Iran to pay $7.5 billion to relatives and other representatives of those killed at the World Trade Center and the Pentagon. The judge determined that Iranian authorities must pay another three billion to insurers who covered property damage and other material losses. Earlier, Judge Daniels ruled that Tehran could not prove its non-involvement in providing assistance to the organizers of the terrorist attack, and therefore the Iranian authorities bear a share of responsibility for the damage caused during it.

On the site of the destruction of the Twin Towers in New York on September 11, 2011, there was the World Trade Center Memorial. It consists of two square fountain pools located right at the bases of the former twin towers, along the inner walls of which streams of water cascade into square holes located at the bottom of each of the pools.

The names of 2,983 terrorist victims (including six who died in the 1993 World Trade Center attack) are carved into bronze slabs that line the parapets of both fountains.

The new World Trade Center complex was opened. It is the fourth tallest skyscraper in the world - its height is 541 meters. Construction began in April 2006 on the corner of a 65,000-square-meter site where the twin towers of a destroyed shopping center previously stood.

Celebrated in the United States as Patriot Day since 2009, after the approval of Act 111-13 of the US General Law, this date is also referred to as the national Day of Service and Remembrance.

The material was prepared based on information from RIA Novosti and open sources