World Trade Center

In the 1960s, the prestige of American democracy shaken. To awaken in the minds of people proud of their country and return to the American people optimism and faith in the future, the project was needed All-American - something big that will affect the stunningly minds and feelings of millions of people.


View on screen one of the twin towers. It is evident that the entire outer skin consists of a huge steel rods.
Projects that can capture the imagination of the American people, put forward a lot. One of the architects, actively engaged in the project, was an American architect Minoru Yamasaki Japanese (1912-1986), already well known for his work, including the airport in St. Louis, the complex structures of the Institute of Arts and Crafts in Detroit, American Concrete Institute.
Minoru Yamasaki conceived the project of the World Trade Center in 1962, in January 1964 commissioned architect «Port Authority» made drawings of buildings, and later that year introduced the model in 1:130 of original size, and two years later (5 August 1966), powerful excavators began digging a pit.


The construction of the WTC in 1971.
Before the twin skyscrapers in New York were built on a natural stone base. Manhattan is really a stone, it has a layer of ground stone, granite, it can be seen when we observe the construction of new houses: there are not dug trenches and felled, coal-cutting teeth gnaw steel hammers.
The first problem faced by engineers, was that in the place where they had to get twins, pasture stone was not there. Instead, they found artificial, alluvial soil, which had "belonged to" the Hudson River. This ground was a large number of artificial ground, mixed with layers of gravel, sand, gravel, pebbles, even old ships caught in the artificial soil. The builders have come to despair: additional constraints, the additional costs, additional concrete.
It was not the only problem that await the architect and engineers. The next problem that befell them, were 164 large and small, narrow and wide buildings, mostly of stone, which stood on the site of the future World Trade Center and had to be demolished. It was not difficult to demolish them, but the problem then still remain. It is much harder to leave at the same time in one piece, and then transfer the rich and complex system of underground utilities, fire alarm system, telephone and multicore electrical cables, gas, heat, air and water pipes, do not touch passing near motorway and save numerous hiking roads and transitions.
Another problem was the station of the underground railroad, hence the underwater path of a start in New Jersey, which carries on the work and takes away from the work of hundreds of thousands of people. If the road was closed, New York and all of the United States expected the inevitable economic problems. Underground transport people up until the bottom tier of the complex is not built a new underground station.
I can not say that the work of the builders was easy. That only cost 1.2 million cubic meters. yards of earth, which had to dig up and remove. Instead, the twins was established under the so-called Plaza - an underground space where there are numerous restaurants, banks, travel agencies, airline offices, shops, a new station in New Jersey to the road, much better than the old, warehouses, workshops for the technical service of twins and an underground garage for two thousand cars.
Faced with the difficulty of constructing a building of unprecedented height, the engineers used advanced structural model: a rigid "hollow tube" of closely spaced steel columns with floor trusses, expanding the central part. On the outer surface of each of the four sides of the building along the entire height was 61 steel beam between them, also on the entire height of the wires were strung. The columns, finished with silvery aluminum alloy was 476.25 mm in width and installed just 558.8 mm from each other because of what distance it seemed that the towers does not have windows. Bearing walls are assembled from prefabricated steel blocks, each weighing 22 tons, the height of 36 feet (height of 4 storeys), width of 10 feet. Two hundred thousand tons in total, weighed steel, laid in Gemini.
As soon as the twins grew up, installers stacked intermediate floors of a special, pre-cooked in the factories of corrugated steel and solid concrete slabs. Ceilings were attached to the exterior bearing walls on the outside and inside, the only twins in the steel columns with highly useful feature - they have erected to secure internal lift.

Elevator system, used in buildings, too, was unique. Twin Towers were the first super-high buildings designed without any masonry. Worried that the intense air pressure created by high-speed elevators, could bend the standard shafts, engineers designed a solution using "suhostennuyu" system, as set forth in the strong steel base. Elevators with a standard configuration for serving 110 floors would require the lower half of the area for the location of the premises of mines. Otis Elevators developed a fast and compact system in which passengers have been replaced by a "sky lobbies" on the 44th and 78th floors, which reduced the number of mines in half. In total, the World Trade Center complex had 239 elevators and 71 escalators, which are controlled by the computer center of the Port Authority. Each lift capacity of 4536 pounds could lift 55 people at a rate of rise - about 8.5 meters per second.
Laying the foundation pit dug in the north tower began in August 1968 including the forces of Italian workers who started working at 8 am and worked until 15:30 with a 40-minute break for lunch at a normal rate, but after half of the fourth worked at double rate: the foreman received $ 40 per hour, respectively, or $ 80 per hour in the evening, and overtime were the rule rather than the exception. [1] Construction proceeded quickly, and despite the difficulties encountered dealing with the financing. The budget of New York in 1965 -1970 years. amounted to 6 billion dollars. To get the money to invest in the construction of World Trade Center, the city issued bonds with a guarantee of repayment. But in 1970 The New York understood the financial crisis. He came up and the term of payments on the bonds. Construction was almost frozen. To save the situation had to introduce a new, higher tax rates in the field of entrepreneurship. Found another source of revenue money: they began to rent out as office space Twins future. And they expected huge - 100 thousand square meters. m Of all the difficulties, managed to finally "get out". North Tower building completed in 1971, the South - in the 1973 Inauguration of the World Trade Center took place on April 4, 1973.
In the section of the tower were square, with sides of 65 meters each Tower - 110 floors. The foundations of structures have gone underground for 23 meters on the skeletons of buildings spent 200 thousand tons of rolled steel, and electrical cable networks, with total capacity of 80,000 kilowatts, stretch for 3000 miles - half the distance from New York to London, across the Atlantic. The structure of the buildings was simple and reasonable. Elevations in the form of steel frames and mounted on aluminum sections are modular size 3,5 × 10 m, prefabricated punching. Such a design earthquake-resistant and can withstand the pressure of the wind is very strong at high altitude. On assurances of architects, each World Trade Center towers could withstand a collision with a few planes, but the September 11, 2001, both WTC towers collapsed to the ground.
Fire February 13, 1975
February 13, 1975 heard three fire alarm on the 11th floor of the North Tower. The fire spread to the central empty tubes to the 9th and 14th floors because of the fire telephone wire in the mine, located vertically between floors. The areas where the fire had penetrated through the wires, was extinguished almost immediately, with a flashpoint managed a few hours. Most of the damage came on the 11th floor where the fire started in an office full of paper, liquid for printing machines and other office equipment. Fire steels himself against the melting point of the skeleton was saved, and the tower had not suffered any structural damage. In second place on the damage caused the lower floors were affected not so much on fire, but from fire foam. At that time, the World Trade Center did not have a system for extinguishing a fire.
A terrorist act February 26, 1993


The destruction of the basement
February 26, 1993 at 12:17 pm of the day at the World Trade Center drove a truck with 680 kg of explosives was driven by Ramzi Youssef. It exploded in the underground garage of the North Tower. As a result of the blast through the five underground floors was done by a hole diameter of 30 meters, causing maximum damage on the levels B1 and B2 in their entire history, and substantial damage to the level of B3. Six people were killed (including during a stampede at the exit) and 50 000 workers and visitors could not breathe because of lack of oxygen at 110 floors of the towers. Many people who were inside the North Tower, I had to go down the dark stairs, and for some it took over two hours.
Josef fled to Pakistan shortly after the explosion, but was arrested in Islamabad in February 1995 and extradited to the U.S. for trial. Sheikh Omar Abdel Rahman in 1996, was accused of involvement in the bombing and other plots. Yousef and Ide Izmoil were sentenced to life imprisonment in 1997 for his involvement in the explosion. Four others are also involved in the bombing were convicted in May of 1994, according to court for the conspirators was a complete destabilization of the North Tower, followed by her had to follow the South - that is, the complete destruction of both towers.
After the explosion took the restoration of the affected floors, especially because they were carrying the structural load and were supporting. The wall of the liquid cement after the explosion was in danger, were also lost metal plates that prevent water pressure from the other side of Hudson. Cooler on sublevel B5, supplying the full range of air the World Trade Center was brought down.
After the attack the port authorities have photoluminescent signs on the walls. The system of notification of the fire had to be completely replaced because the wiring and alarm system of the original system have failed. In memory of the victims was created by reflecting pond with the names of those killed in the blast. As a result of Sept. 11 memorial was destroyed. The new memorial is common for victims of the explosion and the attack will appear in a new complex being built on the site of the former World Trade Center.
The destruction of September 11, 2001



View on fire the World Trade Center
Main article: A terrorist act Sept. 11, 2001, destruction of the World Trade Center towers in New York, the conspiracy theories regarding the events of September 11, 2001
September 11, 2001 terrorists hijacked Flight 11 American Airlines' and made a deliberate collision of it with the North Tower at 08:46 (on the northern facade, between 93 and 99 storeys). After seventeen minutes the second group of terrorists crashed at the same stolen plane Flight 175 (United Airlines Flight 175) Airlines United Airlines in the South Tower (Floors 77-85). Because of the devastation caused by the North Tower of the airframe, were completely blocked all the exits from the building above place of the collision, resulting in the trap were 1344 people. Beat the second aircraft, unlike the first, came closer to the corner of a skyscraper, and one stairwell remained intact. However, few people could easily come down on it until the collapse of the structure. Yet, despite the fact that the plane hit the South Tower fell below here were trapped between floors or killed just under 700 people - far fewer than in the North. At 9:59 South Tower had collapsed due to fire, damaged the steel structural elements, the already weakened by the collision with the aircraft. North Tower collapsed at 10:28 am, after the fire, which lasted 102 minutes.
At 17:20 September 11, 2001 East Penthouse collapsed seventh corps of the World Trade Center (WTC-7), and at 17:21 had collapsed the entire building because of fire spontaneously arising irreversibly destroy its structure. The third building of the World Trade Center, Marriott (WTC-3), was hurt by falling twin towers. The three remaining buildings in the complex were seriously affected by fallen debris, and were eventually torn down, as beyond repair.
Deutsche Bank building on the other side of Liberty Street, opposite the World Trade Center complex was later found to be unsuitable for finding the people in it because of the high content of toxic substances on the premises, and now this building demolished.  Fiterman Hall of the Public Manhattan College in the West Broadway, 30, is also intended to be demolished due to extensive injuries suffered during the attack.


World Trade Center in flames. The moment of collision the second hijacked plane to South Tower
After the attack the media reported that may have been affected tens of thousands of people, as during normal working hours in the complex could be more than 50 000 people. The attack 9/11 were issued 2752 death certificates, including the name of Felicia Dunn-Jones, whose death was registered in May 2007, Dunn-Jones died five months after the terrorist attack because of the terrible state of the lungs, caused by clouds of flying dust during the collapse of World Trade Center towers. Two more victims were later added to the official list of victims: a doctor Snea Anne Philip (Sneha Anne Philip), which was last seen the day before the attack, and Leon Hayward, who died in 2008 of lymphoma, provoked by the inhalation of air saturated with dust, risen in the collapse of the Twin Towers. Cantor Fitzgerald Investment Bank, LP, housed on floors 101-105 of the World Trade Center, lost 658 employees - more than any other institution, even a company Marsh and McLennan, located directly under the premises of the bank on the 93-101 floors (where the plane crashed terrorists) and lost 295 people. In third place on the casualties (175 people) - Aon Corporation (Aon Corporation). Another 343 firefighters died in New York City, 84 employees of the Port Authority - Port Authority of New York and New Jersey, including 37 members of the Police Department Port Authority - Port Authority Police Department (PAPD), and 23 officers of the Police Department in New York. Of all the people who were in the towers when they collapsed, were extracted alive, only 20 people, including policemen PAPD - Will and John McLaughlin Gimeno (eighteenth and nineteenth survivors). [Edit] Consequences
As a result, all seven of the buildings were destroyed, three tallest buildings (North Tower, South Tower and WTC-7) hit (WTC-7 building was attacked, and the official version of the cause of his destruction of the internal fires were due to being hit by debris during attacks on the Twin Towers (before and after the building is not destroyed by fire)), the hotel "Marriott" was almost completely destroyed the WTC rubble-1 and WTC-2, three other buildings had suffered such damage that they have been found unfit for rehabilitation and later demolished. As a result of the collapse of WTC-2 had suffered irreparable damage to the 40-storey building of Deutsche Bank, which is now dismantled.
In place of the collapsed twin towers erected memorial.