The World Trade Center was originally planned to be built on the east side of Lower Manhattan, but the New Jersey and New York state governments, which oversee the Port Authority, could not agree on this location. The Port Authority hired architect Minoru Yamasaki , who came up with the specific idea for twin towers. The towers were designed as framed tube structures , which provided tenants with open floor plans, uninterrupted by columns or walls. This was accomplished using numerous closely spaced perimeter columns to provide much of the strength to the structure, along with gravity load shared with the core columns. The elevator system, which made use of sky lobbies and a system of express and local elevators, allowed substantial floor space to be freed up for use as office space by making the structural core smaller.
Newsday New York. Archived from the original on Construuction 13, Press Room. January 17, All the completed floors were tested but it was found that only one had used a bad batch and it was demolished. Westfield World Trade Center. March 11, What vandalism it would represent what vandalism the present project plans The twin tower construction
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Views Read Edit View history. May Seven World Trade Center opens. November 12, The twin tower construction the beginning of excavation to the completion of the massive foundation took one full year. Engineering News-Record. Boston: Northeastern University Press. In its last iteration, Windows on the World received mixed reviews. Retrieved May 20, Bukowski; Nicholas The twin tower construction. National Public Radio. Archived from the original on July 10, Cudahy, Brian J. Their height was feet. Archived from the original on April 16,
When planning began on the World Trade Center towers, they were only supposed to be ft.
- It opened on April 4, , and was destroyed in during the September 11 attacks.
- There were protests against the construction of the WTC.
In a statement on air , local radio manager Sam Slate said the construction proved that "no home or business is safe from the caprice of government. The anger faded as the skyline made way for seven new buildings, including the landmark Twin Towers, which opened in They were also a symbol of New York City, appearing in numerous films and television shows. On an average weekday in the s, they hosted around 50, employees and 20, visitors.
But the World Trade Center's size and prominence also made it a target for unwanted attention, and ultimately attacks. Over its decades-long history, the structures endured fires, bombings, and robberies, and fell on September 11, when terrorists crashed planes into the towers, killing nearly 3, people and decimating the structures.
Now, after 16 years of construction, the new, seven-building complex on the World Trade Center site is nearing completion. The following aerial images trace the World Trade Center's complicated history, from its groundbreaking in to the grand opening of 3 World Trade Center on June 11, In , workers began demolishing 13 square blocks of Radio Row to make way for the World Trade Center.
The above photo shows the construction site, with the New York Telephone Company in the background and the West Side Highway to the left. By January , construction was in full swing. The building underwent extensive repairs following the bombing, then reopened in November On the morning of September 11, , the World Trade Center site met a devastating end when two planes crashed into the Twin Towers, killing nearly 3, people.
The nine days that followed the attack were dedicated to rescue and recovery efforts. In the wake of the attack, Wall Street came to a standstill.
After being closed for four trading sessions, the stock market reopened on September In , the city held a ceremony to mark the end of its cleanup efforts, which had lasted nearly nine months. The building opened four years later on May 23, Michael Bloomberg, who was New York City's mayor at the time, expressed concern that the national memorial would not be complete by the 10th anniversary of the attack.
Two years later, the memorial debuted on schedule , fulfilling the city's promise to the families of fallen victims. The above image shows the building the day it was finished: November 3, The latest building to be completed, 3 World Trade Center, officially opened on June 11, The structure towers above the reflecting pools at the September 11 Memorial. Hundreds of white oak trees are scattered around the pools, symbolizing the area's renewed growth. Search icon A magnifying glass.
It indicates, "Click to perform a search". Close icon Two crossed lines that form an 'X'. It indicates a way to close an interaction, or dismiss a notification. Aria Bendix.
Construction In popular culture. May 26, Other episodes and films mentioned the attacks directly, or depicted the World Trade Center in alternate contexts. Archived from the original on May 2, February 27, National Geographic :
The twin tower construction. The history of the project
World Trade Center images from construction to today - Business Insider
The World Trade Center was originally planned to be built on the east side of Lower Manhattan, but the New Jersey and New York state governments, which oversee the Port Authority, could not agree on this location.
The Port Authority hired architect Minoru Yamasaki , who came up with the specific idea for twin towers. The towers were designed as framed tube structures , which provided tenants with open floor plans, uninterrupted by columns or walls. This was accomplished using numerous closely spaced perimeter columns to provide much of the strength to the structure, along with gravity load shared with the core columns.
The elevator system, which made use of sky lobbies and a system of express and local elevators, allowed substantial floor space to be freed up for use as office space by making the structural core smaller. Extensive use of prefabricated components helped to speed up the construction process. A seventh building, 7 World Trade Center , was opened in In , Austin J. Tobin became the Executive Director of the Port Authority , beginning a year career during which he oversaw the planning and development of the World Trade Center.
In , a year after the war formally ended, the New York State Legislature passed a bill that called for a "world trade center" to be established. This trade center would increase New York City's role in transatlantic trade. Dewey to develop plans for the project. Meanwhile, the Financial District of Lower Manhattan was left out of the economic boom of financial industries there.
David Rockefeller suggested that the Port Authority would be a logical choice for taking on the project  because it had experience with similar large engineering projects, and also because the Port Authority, rather than Rockefeller, would be paying for the complex's construction.
Tobin remarked that the proposed project should be the World Trade Center, and not just a generic "world trade center". The States of New York and New Jersey also needed to approve the project, given their control and oversight role of the Port Authority. Even though Nelson Rockefeller had been warned of the hastiness of the deal, owing to the fact that it highlighted the price disparity between the two agreements, the New York state legislature approved the bill anyway.
After taking a walk around the Radio Row neighborhood, Schachter concluded that the site could be used for the World Trade Center. The new location not only was closer to New Jersey, but also was able to utilize the unused air rights above the Hudson Terminal: although other developers were theoretically allowed to build atop the terminal, none had done so. Tozzoli to lead the new office.
This would become the site of 7 World Trade Center , although that building was not added until much later. The two blocks to the west and east of the "cork" were occupied by the New York Telephone Company Building and the Federal Building, respectively.
The site for the World Trade Center was the location of Radio Row, which was home to commercial or industrial tenants, over one thousand offices, many small businesses, and approximately residents. Small Businessman" in a mock funeral. The Port Authority opened an office to assist tenants with relocation; although this offer was accepted by some tenants, it was protested by others. Nadel believed that this would allow the Port Authority to convince individual tenants to move out, thus causing an exodus of merchants from the area.
However, when the meeting did occur in mid-June , Nadel immediately rejected Tobin's proposal to give him a storefront space in the World Trade Center. The dispute with local business owners went through the court system to the New York State Court of Appeals. Although several lower courts refused to hear the merchants' cases, they also ruled that the World Trade Center did not serve a "public purpose" and that the plan had caused harm to Radio Row merchants, contrary to what Tobin had claimed.
However, in public, he acted as though the judges had already ruled in his favor on the constitutional question. Under the state law, the Port Authority was required to assist business owners in relocating, something it had been doing since First, the agency approached the United States Customs Service because the Customs Service had been dissatisfied with its current headquarters, the Alexander Hamilton U.
Custom House on the tip of Lower Manhattan. The Port Authority then solicited the New York state government, since there were too few private companies willing to move to the World Trade Center. After considering these facts, Tobin and Tozzoli determined that the only way to make the World Trade Center appealing to private entities was to make the trade center the world's largest.
Fearing controversy, Tobin kept this plan secret from the public. Tozzoli dismissed the three planners who had worked on the original World Trade Center study, due to their lack of creative designs for the World Trade Center complex. Tozzoli had a general idea of what should be in the trade center, but had not yet devised the specific details of the design.
Yamasaki remarked that the "obvious alternative, a group of several large buildings, would have looked like a housing project. Another major limiting factor in the buildings' designs was elevators.
Thus, the local elevators can be stacked within the same elevator shaft. Yamasaki's final design for the World Trade Center was unveiled to the public on January 18, , with an eight-foot model. The plaza was modelled after Mecca , incorporating features such as a vast delineated square, a fountain , and a radial circular pattern.
Yamasaki described the plaza as "a mecca, a great relief from the narrow streets and sidewalks of the Wall Street area. The World Trade Center design brought criticism of its aesthetics from the American Institute of Architects and other groups. Guy F. Monti, the Port Authority's Chief Engineer, oversaw the project. As an interstate agency, the Port Authority was not subject to local laws and regulations of the City of New York, including building codes.
Nonetheless, the Port Authority required architects and structural engineers to follow the New York City building codes. At the time when the World Trade Center was planned, new building codes were being devised to replace the version that was still in place. The structural engineers ended up following draft versions of the new building codes, which incorporated "advanced techniques" in building design.
The World Trade Center towers included many structural engineering innovations in skyscraper design and construction , which allowed the buildings to reach new heights and become the tallest in the world. Traditionally, skyscrapers used a skeleton of columns distributed throughout the interior to support building loads, with interior columns disrupting the floor space. The buildings used high-strength, load-bearing perimeter steel columns which acted as Vierendeel trusses.
The perimeter columns were designed to provide support for virtually all lateral loads such as wind loads and to share the gravity loads with the core columns. The perimeter structure was constructed with extensive use of prefabricated modular pieces, which consisted of three columns, three stories tall, connected by spandrel plates.
The spandrel plates were located at each floor, transmitting shear stress between columns, allowing them to work together in resisting lateral loads. The building's core housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The North Tower's structural core was oriented with the long axis east to west, while the South Tower's was oriented north to south. All elevators were located in the core. Each building had three stairwells, also in the core, except on the mechanical floors where the two outside stairwells temporarily left the core in order to avoid the express elevator machine rooms, and then rejoined the core by means of a transfer corridor.
The large, column-free space between the perimeter and core was bridged by prefabricated floor trusses. The floors supported their own weight, as well as live loads , provided lateral stability to the exterior walls, and distributed wind loads among the exterior walls. The top chords of the trusses were bolted to seats welded to the spandrels on the exterior side and a channel welded to the core columns on the interior side.
The floors were connected to the perimeter spandrel plates with viscoelastic dampers, which helped reduce the amount of sway felt by building occupants. Hat trusses or "outrigger truss" located from the th floor to the top of the buildings were designed to support a tall communication antenna on top of each building. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower. Subjects were recruited for "free eye exams," while the real purpose of the experiment was to subject them to simulated building sway and find out how much they could comfortably tolerate.
Davenport to develop viscoelastic dampers to absorb some of the sway. These viscoelastic dampers, used throughout the structures at the joints between floor trusses and perimeter columns, along with some other structural modifications reduced the building sway to an acceptable level.
The structural engineers on the project also considered the possibility that an aircraft could crash into the building. In July , a B bomber that was lost in the fog had crashed into the 78th and 79th floors of the Empire State Building. A year later, another airplane crashed into the 40 Wall Street building, and there was another close call at the Empire State Building.
Sprayed-fire resistant materials SFRMs were used to protect some structural steel elements in the towers, including all floor trusses and beams. Gypsum wallboard in combination with SFRMs, or in some cases gypsum wallboard alone, was used to protect core columns. Vermiculite plaster was used on the interior-side and SFRMs on the other three sides of the perimeter columns for fire protection.
The Port Authority was in the process of replacing it, but replacement had been completed on only 18 floors in the North Tower, including all the floors affected by the aircraft impact and fires on September 11,  and on 13 floors in the South Tower, although only three of these floors 77, 78, and 85 were directly affected by the aircraft impact. The New York City building codes did not require sprinklers for high-rise buildings, except for underground spaces.
In accordance with building codes, sprinklers were originally installed only in the underground parking structures of the World Trade Center. By , nearly all of the South Tower and 85 percent of the North Tower had sprinklers installed  and the entire complex was retrofitted by Even once the agreement between the states of New Jersey, New York, and the Port Authority had been finalized in , the World Trade Center plan faced continued controversy.
Wagner Jr. By , by which time the intended scale of the scheme had been made public with plans for twin story towers, private real estate developers and members of the Real Estate Board of New York also expressed concerns about the World Trade Center's much-"subsidized" office space going on the open market, competing with the many vacancies in the private sector.
The city and developers used a myriad of arguments to stall construction for two years. Wagner's successor, John Lindsay , and the New York City Council raised concerns about the limited extent that the Port Authority involved the city in the negotiations and deliberations. This dispute went on for two years, during which time the projected price of the World Trade Center increased sharply. By July , neither the city or the Port Authority were able to come to an agreement. Groundbreaking was on August 5, , marking the beginning of construction of the World Trade Center's foundations.
This method was used in place of conventional dewatering methods because lowering the groundwater table would cause large settlements of nearby buildings not built on deep foundations.
The slurry method involved digging a trench , and as excavation proceeded, filling the space with a "slurry" mixture. The mixture, composed of bentonite , plugged holes and kept water out. When the trench was dug out, a steel cage was inserted and concrete was poured in, forcing the "slurry" out.
The "slurry" method was devised by Port Authority chief engineer John M. Kyle Jr. Towards the end of , work began on building the slurry wall, led by Montreal -based Icanda, a subsidiary of an Italian engineering firm, Impresa Costruzioni Opere Specializzate I.
Construction work began on the North Tower in August with construction beginning on the South Tower by January Steel as a cost-saving measure. Extensive use of prefabricated parts for the perimeter framing and floor truss systems helped speed up the construction process and reduce costs, while providing greater quality control.
From there, they were brought in the early morning hours through the Holland Tunnel to the construction site, then lifted into place by a crane.