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One World Trade Center
1 WTC, the tallest skyscraper in the Western Hemisphere, in July 2013.
Alternative names	1 WTC Freedom Tower (pre-2009)
General information
Status	Topped out Interior furnishing and exterior under construction
Type	Office, observation, communication
Architectural style	Contemporary modern
Location	72 Vesey Street New York City, NY 10007 United States
Construction started	April 27, 2006
Opening	2014
Cost	US$3.9 billion (April 2012 estimate)
Height
Architectural	1,776 ft (541.3 m)
Tip	1,792 ft (546.2 m)
Roof	1,368 ft (417.0 m)
Top floor	1,268 ft (386.5 m)
Observatory	1,254 ft (382.2 m)
Technical details
Floor count	104 (+5 basement floors)
Floor area	3,501,274 sq ft (325,279 m)
Lifts/elevators	73
Design and construction
Architect(s)	David Childs (Skidmore, Owings & Merrill)
Developer	Port Authority of New York and New Jersey
Structural engineer	WSP Cantor Seinuk
Main contractor	Tishman Construction
References

One World Trade Center (also 1 World Trade Center or 1 WTC, dubbed the Freedom Tower during initial basework) is the name of two buildings. It most commonly refers to the primary building of the new World Trade Center complex in Lower Manhattan, New York City, and the tallest skyscraper in the Western Hemisphere. The 104-story supertall structure, which shares a name with the northern Twin Tower in the original World Trade Center that was destroyed in the September 11, 2001 terrorist attacks, stands on the northwest corner of the 16-acre (6.5 ha) World Trade Center site, on the site of the original 6 World Trade Center. The building is bordered to the west by West Street, to the north by Vesey Street, to the south by Fulton Street, and to the east by Washington Street. Construction on below-ground utility relocations, footings, and foundations for the building began on April 27, 2006. On March 30, 2009, the Port Authority of New York and New Jersey confirmed that the building would be known by its legal name, One World Trade Center, rather than the colloquial name, Freedom Tower.

The tower's steel structure topped out on August 30, 2012. On May 10, 2013, the final component of the skyscraper's spire was installed, making One World Trade Center the fourth-tallest skyscraper in the world at the time by pinnacle height. Its spire reaches a symbolic height of 1,776 feet (541 m) in reference to the year of the United States Declaration of Independence. It has been the tallest structure in New York City since April 30, 2012, when it surpassed the height of the Empire State Building. The new World Trade Center complex, in which One World Trade Center will open in 2014, will also feature three other high-rise office buildings, located along Greenwich Street, and the National September 11 Memorial & Museum, located just south of One World Trade Center, where the Twin Towers once stood. The construction is part of an effort to memorialize and rebuild following the destruction of the original World Trade Center complex during the attacks of September 11, 2001.

History

Original building

Construction

The construction of the World Trade Center, of which the Twin Towers (One and Two World Trade Center) were the centerpieces, was conceived as an urban renewal project, spearheaded by David Rockefeller, to help revitalize Lower Manhattan. The project was developed by the Port Authority of New York and New Jersey, which hired architect Minoru Yamasaki who came up with the specific idea for twin towers. After extensive negotiations, the New Jersey and New York State governments, which oversee the Port Authority, agreed to support the World Trade Center project at the Radio Row site on the lower-west side of Manhattan. To make the agreement acceptable to New Jersey, the Port Authority agreed to take over the bankrupt Hudson & Manhattan Railroad (renamed as PATH), which brought commuters from New Jersey to the Lower Manhattan site.

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. The design and construction of the World Trade Center twin towers involved many other innovative techniques, such as the slurry wall for digging the foundation, and wind tunnel experiments.

The North Tower (One World Trade Center) began in August 1968; extensive use of prefabricated components helped to speed up the construction process. The first tenants moved into the North Tower in December 1970. Later, four other low-level buildings were constructed as part of the World Trade Center in the 1970s. A seventh building was constructed in the mid-1980s.

Existence

With the construction of Seven World Trade Center in the 1980s, the World Trade Center had a total of seven buildings, but the most notable were the main two towers built in the 1960s—One World Trade Center being the North Tower and Two World Trade Center being the South Tower. Each stood over 1,350 feet (410 m) high, and occupied about 1 acre (4,000 m) of the total 16 acres (65,000 m) of the site's land. During a press conference in 1973, Yamasaki was asked, "Why two 110-story buildings? Why not one 220-story building?" His response was: "I didn't want to lose the human scale."

When completed in 1972, 1 World Trade Center became the tallest building in the world for two years, surpassing the Empire State Building after a 40-year reign. The North Tower stood 1,368 feet (417 m) tall and featured a telecommunications antenna or mast that was added at the top of the roof in 1978 and stood 360 feet (110 m) tall. With the 360-foot (110 m)-tall antenna/mast, the highest point of the North Tower reached 1,728 ft (527 m). The World Trade Center towers held the height record only briefly: Chicago's Sears Tower, finished in May 1973, reached 1,450 feet (440 m) at the rooftop. Throughout their existence, however, the WTC towers had more floors (at 110) than any other building. This number was not surpassed until the advent of the Burj Khalifa, which opened in 2010.

Of the 110 stories, eight were set aside for technical services in mechanical floors (floors 7/8, 41/42, 75/76, and 108/109), which are four two-floor areas that evenly spaced up the building. All the remaining floors were free for open-plan offices. Each floor of the tower had 40,000 square feet (3,700 m) of space for occupancy. The tower, as well as its counterpart, had 3,800,000 square feet (350,000 m) of office space in total. Altogether, the entire complex of seven buildings had a combined 13,400,000 square feet (1,240,000 m) of office space.

Initially conceived as a complex dedicated to companies and organizations directly taking part in "world trade", it at first failed to attract the expected clientele. During the early years, various governmental organizations became key tenants of the World Trade Center including the State of New York. It was not until the 1980s that the city's perilous financial state eased, after which an increasing number of private companies—mostly financial firms tied to Wall Street—became tenants. During the 1990s, approximately 500 companies had offices in the complex including many financial companies such as Morgan Stanley, Aon Corporation, Salomon Brothers and the Port Authority itself. The basement concourse of the World Trade Center included The Mall at the World Trade Center, along with a PATH station. The North Tower became the home of the corporate headquarters of Cantor Fitzgerald, and it also became the headquarters of the Port Authority of New York and New Jersey.

Electrical service to the tower was supplied by Consolidated Edison (ConEd) at 13,800 volts. This service passed through the World Trade Center Primary Distribution Center (PDC) and sent up through the core of the building to electrical substations located on the mechanical floors. The substations stepped down the 13,800 primary voltage to 480/277 volt secondary service, and then further down to 208/120 volt general power and lighting service. The complex also was served by emergency generators located in the sub-levels of the towers and on the roof of 5 WTC.

The 110th floor of 1 World Trade Center (the North Tower) housed radio and television transmission equipment. The roof of 1 WTC contained a vast array of transmission antennas including the 360 ft (approx 110 m) center antenna mast, rebuilt in 1999 by Dielectric Inc. to accommodate DTV. The center mast contained the television signals for almost all NYC television broadcasters: WCBS-TV 2, WNBC-TV 4, WNYW 5, WABC-TV 7, WPIX 11, WNET 13 Newark, WPXN-TV 31 and WNJU 47 Linden. It also had four NYC FM broadcasters: WPAT-FM 93.1, WNYC 93.9, WKCR 89.9, and WKTU 103.5. Access to the roof was controlled from the WTC Operations Control Center (OCC) located in the B1 level of 2 WTC. After the September 11 attacks in 2001, the equipment to broadcast the radio and television stations was moved to the Empire State Building.

On a typical weekday, a combined 50,000 people worked in the North and South towers with another 200,000 passing through as visitors. The complex was so large that it had its own zip code: 10048. The Windows on the World restaurant on top of the North Tower offered expansive views. The Twin Towers became known worldwide, appearing in numerous movies and television shows as well as on postcards and other merchandise, and became seen as a New York icon, in the same league as the Empire State Building, Chrysler Building, and the Statue of Liberty.

Incidents

On February 13, 1975, a three-alarm fire broke out on the 11th floor of the North Tower. Fire spread through the core to the 9th and 14th floors by igniting the insulation of telephone cables in a utility shaft that ran vertically between floors. Areas at the furthest extent of the fire were extinguished almost immediately and the original fire was put out in a few hours. Most of the damage was concentrated on the 11th floor, fueled by cabinets filled with paper, alcohol-based fluid for office machines, and other office equipment. Fireproofing protected the steel and there was no structural damage to the tower. In addition to damage caused by the fire on the 9th - 14th floors, water from the extinguishing of the fires damaged a few floors below. At that time, the World Trade Center had no fire sprinkler systems.

The first Islamist terrorist attack on the World Trade Center occurred on February 26, 1993, at 12:17 p.m., a Ryder truck filled with 1,500 pounds (680 kg) of explosives, planted by Ramzi Yousef, detonated in the underground garage of the North Tower. The blast opened a 100 foot (30 m) hole through five sublevels with the greatest damage occurring on levels B1 and B2 and significant structural damage on level B3. Six people were killed more than a thousand, were injured, and 50,000 other workers and visitors were left gasping for air within the 110 story towers. Many people inside the North Tower were forced to walk down darkened stairwells that contained no emergency lighting, some taking two hours or more to reach safety.

September 11 attacks

At 8:46 a.m., five hijackers crashed American Airlines Flight 11 into the northern facade of the World Trade Center's North Tower (1 WTC).

The North Tower collapsed at 10:28 a.m. after burning for 102 minutes due to structural failure. When the North Tower collapsed, debris fell on the nearby 7 World Trade Center building (7 WTC), damaging it and starting fires. These fires burned for hours, compromising the building's structural integrity, and 7 WTC collapsed at 5:21 p.m.

The attacks resulted in the deaths of 2,996 people, including the 19 hijackers and 2,977 victims. Nearly all of the victims were civilians; 55 military personnel were among those killed at the Pentagon. More than 90% of the workers and visitors who died in the towers had been at or above the points of impact. In the North Tower 1,355 people at or above the point of impact were trapped and died of smoke inhalation, fell or jumped from the tower to escape the smoke and flames, or were killed in the building's eventual collapse. The destruction of all three staircases in the tower when Flight 11 hit made it impossible for anyone above the impact zone to escape. One hundred and seven people below the point of impact died as well.

New building

Planning and development

Following the destruction of the original World Trade Center by Al-Qaeda-affiliated terrorists, there was debate regarding the future of the World Trade Center site. Proposals for its reconstruction began almost immediately, and by 2003, the Lower Manhattan Development Corporation organized a competition to determine how to use the site. Public rejection of the first round of designs, the "Preliminary Design Concepts", led to a second, more open competition in December 2002, in which a design by Daniel Libeskind was selected. This went through many revisions, largely because of disagreements with developer Larry Silverstein, who held the lease to the World Trade Center site on September 11, 2001.

Criticism was leveled at the limited number of floors that were designated for office space and other amenities in an early plan. Only 82 floors would have been habitable, and the overall office space of the entire rebuilt World Trade Center would have been reduced by more than 3,000,000 square feet (280,000 m) in comparison with the original complex. The floor limit was imposed by Silverstein, who expressed concern that higher floors would be a liability in the event of a future terrorist attack or other incident. Much of the building's height would have consisted of a large, open-air steel lattice structure above the roof of the tower, containing wind turbines and "sky gardens". In a subsequent design, the highest space that could be occupied became comparable to the original World Trade Center, and the open-air lattice was removed from the plans. In 2002, former New York Governor George Pataki faced accusations of cronyism for supposedly using his influence to get the winning architect's bid picked as a personal favor for his friend and campaign contributor, Ron Lauder.

A final design for the "Freedom Tower" was formally unveiled on June 28, 2005. To satisfy security issues raised by the New York City Police Department, a 187-foot (57 m) concrete base was added in April of that year. The design originally included plans to clad the base in glass prisms to address criticism that it looked uninviting and resembled a "concrete bunker". However, this later proved unworkable, as preliminary testing revealed that the prismatic glass easily shattered into large and dangerous shards. As a result, it was replaced by a simpler facade consisting of stainless steel panels and blast-resistant glass.

Contrasting with Libeskind's original plan, the tower's final design tapers octagonally as it rises. Its designers stated that the tower would be a "monolithic glass structure reflecting the sky and topped by a sculpted antenna." Larry Silverstein commented in 2006 on a planned completion date: "By 2012 we should have a completely rebuilt World Trade Center, more magnificent, more spectacular than it ever was." On April 26, 2006, the Port Authority of New York and New Jersey approved a conceptual framework that enabled foundation construction to begin, and a formal agreement was drafted on the following day, the 75th anniversary of the 1931 opening of the Empire State Building. The tower's construction began in May with a formal ceremony that took place when the first construction team arrived. The building's topping out occurred on August 31, 2012, and was completed on May 2, 2013.

In 2009 the Port Authority changed the official title of the building from "Freedom Tower" to "One World Trade Center," stating that this name was the "easiest for people to identify with." The change came after board members voted to sign a 21-year lease deal with Vantone Industrial Co., a Chinese real estate company, which will become the building's first commercial tenant. Vantone plans to create the China Center, a trade and cultural facility, covering 191,000 square feet on floors 64 through 69.

A report in September 2013 revealed that, at the time of the report, the World Trade Center Association (WTCA) continues to negotiate with the One World Trade Center in regard to the title "World Trade Center", as the WTCA purchased the rights to the name in 1986. The WTCA is seeking free office space in the tower worth US$500,000 in exchange for the use of "World Trade Center" on the One World Trade Center tower and associated souvenirs.

In May 2011, detailed floor plans of the tower were displayed on New York City's Department of Finance website, resulting in an uproar from the media and citizens of the surrounding area, who warned that the plans could potentially be used for a future terrorist attack. In April 2012, with the tower's structure nearing completion, the owners of 1 WTC began a public marketing campaign for the building, seeking to draw in visitors and additional tenants.

On November 12, 2013, the Height Committee of the Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH) made the controversial announcement that One World Trade Center was the tallest building in the United States at 1,776 feet, declaring that the mast on top of the building is a spire since it is a permanent part of the building's architecture.

Construction

The symbolic cornerstone of One World Trade Center was laid in a ceremony on July 4, 2004, but further construction work was stalled until 2006 due to disputes over money, security and design. The last major issues were resolved on April 26, 2006, when a deal was struck between developer Larry Silverstein and the Port Authority of New York and New Jersey. For two months during the summer of 2006, explosives were detonated at the World Trade Center construction site, testing the use of charges to clear bedrock for the building's foundations. On November 18, 2006, 400 cubic yards (310 cubic meters) of concrete were poured onto the foundations, carried by as many as 40 trucks. On December 17, 2006, a ceremony was held in Battery Park City, with members of the public invited to sign a 30-foot (9.1 m) steel beam. This beam, the first to be installed, was welded onto the building's base on December 19, 2006. Afterwards, construction of the foundation and further steel installation commenced, and by the end of 2007, the tower's footings and foundations were nearly complete.

In January 2008, two construction cranes were moved onto the construction site. The tower's concrete core began rising in the first months of 2008, and had reached street level by May 17. Construction of the base continued through 2009 and was completed by January 2010. That same month, construction of the office floors began, then afterwards the installation of the first glass windows. In May 2010, the Port Authority stated that they were building nearly one floor of the tower per week, and it was projected that 1 WTC would reach 55 stories by the end of 2010. An advanced "cocoon" scaffolding system was installed to protect workers from falling, marking the first time that such a safety system had been installed on a steel structure in the city.

On December 16, 2010, the Port Authority announced that the tower's construction had reached the 52nd floor, rising to over 600 feet (180 m) and marking the halfway point for the tower's steel frame. By September 11, 2011, ten years after the destruction of the original World Trade Center, the tower's steel had reached the 82nd floor, while its concrete flooring had reached the 72nd floor, and glass cladding had reached the 56th floor.

While under construction, the tower was specially illuminated on several occasions. On the weekend of July 4, 2011, it was lit up in the colors of the American flag to commemorate Independence Day, and it was lit up in the same colors on September 10 to mark the 10th anniversary of the September 11 terrorist attacks. On October 27, it was illuminated in pink in honor of Breast Cancer Awareness Month. On December 11, the Port Authority illuminated the tower in multicolored lights to celebrate the holiday season. On February 24, 2012, the building was lit up in red in honor of Archbishop of New York Timothy Dolan, who became a cardinal on February 18. On June 14, 2012, it was illuminated in red, white, and blue to honor Flag Day. In August, it was illuminated in red in honor of the Armed Forces. On September 8, 2012, it was again illuminated in red, white, and blue to honor the 11th anniversary of the September 11 attacks. On June 24, 2013, One World Trade Center was again illuminated in red, white, and blue to celebrate the Fourth of July. On November 12, 2013, three hundred red, white, and blue lights were lit up.

On January 31, 2012, the Port Authority stated that the tower's loading dock would not be finished in time to move equipment into the completed building, and that five temporary loading bays would be added instead, at a cost of millions. The temporary Trans Hudson station will not be removed until its replacement is completed, preventing access to the planned loading area. By March 2012, One World Trade Center's steel had reached the 93rd floor, and on March 30, the 100th floor was reached at a height of 1,240 feet (380 m). Though this floor was numbered as floor 100, it was in fact the 94th floor constructed since the intervening space was occupied by the high-ceilinged mechanical 91st floor. The incomplete tower became New York City's tallest building by roof height, superseding the 1,250-foot (380 m) roof height of the Empire State Building, on April 30, 2012. However, the Empire State Building's total spire height of 1,454 feet (443 m) remained unsurpassed until 2013, when One World Trade Center's antenna was installed.

On June 2, 2012, a fire broke out on the 89th floor of the tower, but was extinguished by New York City firefighters before causing any injuries or serious structural damage. However, firefighting efforts were delayed because the tower's emergency standpipes were found to be dry. On June 14, 2012, President Barack Obama visited the construction site and signed a steel beam that would be hoisted to the top of the tower. Obama wrote, "We remember, we rebuild, we come back stronger!"

In August 2012, One World Trade Center's steel officially topped out at the nominal 104th floor, at a total height of 1,368 feet (417 m). The tower's antenna was shipped to New York in November 2012; the first antenna section was hoisted to the top of the tower on December 12, 2012, and installed on January 15, 2013.

By March 2013, two sections of the antenna had been installed. The spire was expected to be completed on April 29, 2013, but weather delayed the delivery of the final pieces. On May 10, 2013, the final piece of the spire was lifted to the top of One World Trade Center, bringing it to its full height of 1,776 feet (541 m), and making it the third-tallest building in the world.

As of April 2014, the exterior elevator shaft is being removed, podium glass continues to be installed, and interior decorating and finishings are being installed. Installation of concrete flooring and steel fittings is now complete. The building will be ready for occupancy by late 2014. One World Trade Center, following interior fit-out, is scheduled to open to the public by then.

• The original twin WTC towers, c. 2000.

• 1 WTC under construction behind the World Financial Center in June 2011.

• 1 WTC under construction (to the left), as seen from a helicopter on April 30, 2012.

Estimated cost and funding

A February 2007 estimate put the initial construction cost of One World Trade Center at about US$3 billion, or $1,150 per square foot ($12,380 per square meter). However, by April 2012 the tower's total estimated cost had risen to $3.9 billion, making it the most expensive single building in the world at the time. The tower's construction was partly funded with approximately $1 billion of insurance money recouped by Silverstein in connection with the September 11 attacks. The State of New York provided $250 million toward construction costs, and the Port Authority agreed to finance a further $1 billion through the sale of bonds. A series of bridge and tunnel toll hikes were also implemented by the Port Authority to raise funds, with a 56 percent toll increase scheduled between 2011 and 2015; however, the proceeds of these toll hikes were not ultimately used to pay for the tower's construction.

Architecture and design

Many of Daniel Libeskind's concepts from the 2002 competition were later discarded from the tower's design. One World Trade Center's final design consisted of simple symmetries and a more traditional profile, intended to bear comparison with selected elements of the contemporary New York skyline. The tower's central spire draws from precedents such as the Empire State Building and the Chrysler Building, and is also visually reminiscent of the North Tower of the original World Trade Center, rather than being an off-center spire intended to echo the Statue of Liberty.

The building's footprint is a 200-foot (61 m) square with an area of 40,000 square feet (3,700 m), nearly identical to the footprints of the original Twin Towers. The tower rises from a 185-foot (56 m) windowless concrete base, designed to protect it against truck bombs and other ground-level terror threats. Originally, the base was intended to be clad in decorative prismatic glass, but a simpler glass-and-steel façade was adopted when this proved unworkable. The current base cladding design consists of angled glass fins protruding from stainless steel panels, similar to those on 7 World Trade Center. LED lights behind the panels will illuminate the base at night. Cable-net glass façades on all four sides of the building for the higher floors, designed by Schlaich Bergermann, will be consistent with the other buildings in the complex. They measure 60 feet (18 m) high and range in width from 30 feet (9.1 m) on the east and west sides (for access to the observation deck) to 50 feet (15 m) on the north side, and 70 feet (21 m) on the south for primary tenant access. The curtain wall was manufactured and assembled in Portland, Oregon, by Benson Industries, using glass made in Minnesota by Viracon.

From the 20th floor upwards, the square edges of the tower's cubic base are chamfered back, transforming the building's shape into eight tall isosceles triangles, or an elongated square antiprism. Near its middle, the tower forms a perfect octagon in-plan, and then culminates in a glass parapet whose shape is a square oriented 45 degrees from the base. A 408-foot (124 m) sculpted mast containing the broadcasting antenna – designed in a collaboration between SOM, artist Kenneth Snelson (who invented the tensegrity structure), lighting designers and engineers – is secured by a system of cables, and rises from a circular support ring which will contain additional broadcasting and maintenance equipment. At night, an intense beam of light will be projected above the spire, being visible over 1,000 feet (300 m) into the air above the tower.

David Childs of Skidmore, Owings and Merrill, the architect of One World Trade Center, said the following regarding the tower's design:

We really wanted our design to be grounded in something that was very real, not just in sculptural sketches. We explored the infrastructural challenges because the proper solution would have to be compelling, not just beautiful. The design does have great sculptural implications, and we fully understand the iconic importance of the tower, but it also has to be a highly efficient building. The discourse about Freedom Tower has often been limited to the symbolic, formal and aesthetic aspects but we recognize that if this building doesn't function well, if people don't want to work and visit there, then we will have failed as architects.

Layout

One World Trade Center's top floor is designated as 104. The building has 86 usable above-ground floors, of which 78 will be assigned as office space (approximately 2,600,000 square feet or 240,000 square meters). The base occupies floors 1–19, including a 65-ft-high (20 m) public lobby. The office stories will begin at floor 20, and run through floor 63. There is a sky lobby on floor 64, and then office floors resume between floors 65–90. Meanwhile, floors 91–99 and 103–104 are designated as mechanical space.

The tower's design also includes a three-story observation deck located on floors 100–102, as well as broadcast and antenna facilities. Similar to the arrangement at the Empire State Building, observatory visitors are segregated from the users of the tenant floors with their own separate entrance next to the museum, descending down to a below-ground security screening area. Below-ground tenant parking and storage, shopping, and access to PATH and New York City Subway trains and the World Financial Center are also provided at the World Trade Center Transportation Hub and the Fulton Street/Fulton Center, Chambers Street, and Cortlandt Street stations, respectively. The building has approximately 55,000 square feet (5,100 m) of below-ground retail space. A plan to build a restaurant near the top of the tower, similar to the original World Trade Center's Windows on the World, was abandoned as logistically impractical. The tower's window-washing tracks are located on a 16-square-foot area which will be denoted as floor 110, in a symbolic reference to the 110 stories of the original Twin Towers.

Design evolution

The original design went through significant changes after the Durst Organization joined the Port Authority of New York and New Jersey in 2010 as the co-developer of the project.

• The 185-foot (56 m) base of the tower:
  • Its corners were originally designed to slope gently upward, and had prismatic glass.
  • The corners were later squared off. In addition, its walls are now covered in "hundreds of pairs of 13-foot vertical glass fins set against horizontal bands of eight-inch-wide stainless-steel slats."
• The spire:
  • It was originally intended to be enclosed with a protective radome described as a "sculptural sheath of interlocking fiberglass panels".
  • It remained an antenna instead; however, the Council on Tall Buildings and Urban Habitat announced that the building is officially 1776 feet tall. Douglas Durst, the chairman of the Durst Organization, stated that the design change would save $20 million. However, the tower's architect, Skidmore Owings & Merrill, strongly criticized the move. David Childs, the lead designer, stated: "Eliminating this integral part of the building's design and leaving an exposed antenna and equipment is unfortunate...We stand ready to work with the Port on an alternate design." After joining the project in 2010, the Durst Organization had proposed eliminating the radome to save costs, but was rejected by the Port Authority's then-executive director, Christopher O. Ward. Ward's September 2011 replacement, Patrick Foye, later changed the Port Authority's position. In 2012, Douglas Durst gave a statement regarding the final decision: "(the antenna) is going to be mounted on the building over the summer. There's no way to do anything at this point."
• The large triangular plaza on the west side of 1 World Trade Center, facing the Hudson River, which is at an elevation to Vesey Street to the north and West Street to the east:
  • It was planned to have stainless steel steps reaching down to the streets.
  • Instead it will be a terrace. Durst also removed a skylight set into the plaza which was designed to allow natural light into the observation deck lobby below ground. The plaza is now 5 ft 8 in (1.73 m) higher than the adjacent sidewalk. The terrace above sidewalk level that is accessible by a staircase on Vesey Street. The terrace would be paved in granite, and have 12 sweetgum trees in addition to the block-long planter/bench.

The Port Authority formally approved all these revisions, which were first reported by the New York Post. Patrick Foye, the executive director of the Port Authority, said in a telephone interview that he thought that the changes were "few and minor." Douglas Durst stated that the edits to the original design were made so that the building could be built, rather than for design purposes. The contract negotiated between the Port Authority and the Durst Organization specifies that the Durst Organization receive a $15 million fee and a percentage of "base building changes that result in net economic benefit to the project." The specifics of the signed contract give Durst 75 percent of savings up to $24 million, and further returns stepping down thereafter (to 50 percent, 25 percent and 15 percent as the savings increase).

Height

The roof of the top floor of One World Trade Center is 1,368 feet (417 m) tall, including a 33 ft 4 in (10.16 m) parapet; this is identical to the roof height of the North Tower of the original World Trade Center. The building's antenna/spire complex brings One World Trade Center to a pinnacle height of 1,776 feet (541 m), a figure symbolic of the 1776 United States Declaration of Independence. If the antenna is included in the building's official height, as defined by the Council on Tall Buildings and Urban Habitat (CTBUH), One World Trade Center surpasses the 1,671-foot (509 m) height of Taipei 101 and is the world's tallest all-office building, and the fourth-tallest skyscraper in the world, behind the Burj Khalifa, Abraj Al Bait, and Shanghai Tower.

One World Trade Center is the second-tallest freestanding structure in the Western Hemisphere, as its pinnacle height is exceeded by that of the CN Tower in Toronto by approximately 12 m (39.4 ft). The Chicago Spire, with a planned height of 2,000 feet (610 m), was expected to exceed the height of One World Trade Center, but its construction was canceled in 2009 due to financial difficulties.

After the changes in the design of One World Trade Center's spire were revealed in May 2012, questions were raised as to whether the 408-foot (124 m) structure would still qualify as a spire and thus be included in the building's official architectural height. As the building's spire is not enclosed in a radome as originally planned, it may instead be classified as a simple antenna which, according to the CTBUH, is not included in a building's official height. Without the inclusion of the antenna mast, One World Trade Center's official height would be its roof height of 1,368 feet (417 m), making it the third-tallest building in the United States, behind the Willis Tower and Trump International Hotel & Tower, both located in Chicago. Additionally, while the building is the tallest in New York City now either way, without the antenna it would be surpassed in 2015 by the under-construction 432 Park Avenue, which is expected to rise to a height of 1,398 feet (426 m). One World Trade Center's developers have disputed the claim that the spire should be reclassified as an antenna following the redesign, with Port Authority spokesman Steve Coleman reiterating that "One World Trade Center will be the tallest building in the Western Hemisphere." The CTBUH announced in 2012 that it would wait to make its final decision as to whether or not the redesigned spire would count towards the building's official height. On November 12, 2013, the CTBUH announced that the spire on One World Trade Center would count as part of the building's official height, giving it a final height of 1,776 ft and making it the tallest building in the Western Hemisphere.

Sustainability

Like the other buildings of the rebuilt World Trade Center complex, One World Trade Center includes a number of sustainable architecture features. Much of the building's structure and interior is made from recycled materials, including gypsum boards and ceiling tiles, and about 80 percent of its waste products are also being recycled. Although the roof area of any tower is comparatively limited, the building will implement a rainwater collection and recycling scheme for its cooling systems. The building's PureCell phosphoric acid fuel cells will generate 4.8  Megawatts (MW) of power, and its waste steam will also help generate electricity. The New York Power Authority selected UTC Power to provide the tower's fuel cell system, which will rank as one of the largest installations of fuel cells in the world once complete. The tower will also make use of off-site hydroelectric and wind power. The windows are made of an ultra-clear glass which allows maximum daylight to pass through, while interior lighting is equipped with dimmers that automatically lower the lights on sunny days, thereby reducing energy costs. Like all of the new facilities at the World Trade Center site, One World Trade Center will be heated by steam, with limited oil or natural gas utilities located on-site.

One World Trade Center is expected to receive a Leadership in Energy and Environmental Design (LEED) Gold Certification, making it one of the most environmentally sustainable buildings of its size in the world.

Safety and security

Security features

Along with the protection offered by the reinforced concrete base, a number of other safety features were included in the building's design, in order to better prepare it for a major accident or terrorist attack. In line with the new philosophy set by 7 World Trade Center, the building features 3-foot (91 cm) thick reinforced concrete walls for all stairwells, elevator shafts, risers, and sprinkler systems; extra-wide, pressurized stairwells; a dedicated set of stairwells exclusively for the use of firefighters; and biological and chemical filters throughout its ventilation system. By way of comparison, the Twin Towers used a purely steel central core to house their utility functions, protected only by a system of lightweight drywall panels.

The building is no longer 25 feet (8 m) away from West Street, as the Twin Towers were; at its closest point, West Street is 65 feet (20 m) away. The windows on the side of the building facing in this direction are equipped with specially tempered blast-resistant plastic, which looks nearly the same as the glass used in the other sides of the building. The Port Authority has stated: "Its structure is designed around a strong, redundant steel moment frame consisting of beams and columns connected by a combination of welding and bolting. Paired with a concrete-core shear wall, the moment frame lends substantial rigidity and redundancy to the overall building structure while providing column-free interior spans for maximum flexibility."

In addition to optimal safety design, new security measures will also be implemented. All vehicles will be screened before they enter the site via the underground roadway, including for radioactive materials. Visitors to the National September 11 Memorial undergo airport-style screening as part of the "Interim Operating Period", which was expected to end on December 31, 2013; the security screening is still in effect as of early 2014. Four hundred closed-circuit surveillance cameras will be placed in and around the site, with live camera feeds being monitored around the clock by the NYPD. A computer system will use video-analytic computer software designed to detect potential threats such as unattended bags and retrieve images based on descriptions of terror or other criminal suspects. New York City and Port Authority police will patrol the site. Once the World Trade Center site is fully completed, the plaza will be opened entirely to the public, as was the original World Trade Center plaza.

Incidents

The tower was scaled in March 2014 by 16-year-old New Jersey resident Justin Casquejo, who entered the site through a hole in a fence. He was subsequently arrested on trespassing charges and apologized for the disruption, but gave no apology for trespassing. He allegedly dressed like a construction worker, then snuck in and convinced an elevator operator into giving him a lift to the tower’s 88th floor, according to news sources. He then used stairways to get to the 104th floor, walked past a sleeping security guard, and climbed up a ladder to get to the antenna, where he took pictures for two hours. The elevator operator has since been reassigned, and the guard was fired. It was then revealed that officials at One World Trade Center had failed to install any security cameras inside the building, which facilitated Casquejo's entry to the site.

Less than a week later, four people—three male parachutists (one of whom was a construction worker at the site) and their lookout—were also arrested, but for a BASE jump they conducted on September 30, 2013. They had posted their video of their doing the jump online.

As a result of these incidents, the Durst Organization's head of security at One World Trade Center, David Velazquez, resigned on March 28, 2014.

Controversy

The social center of the old World Trade Center included a spectacular restaurant on the 107th Floor, called Windows on the World, and its Greatest Bar in the World; these were tourist attractions in their own right, and a social gathering spot for people who worked in the towers. This restaurant also housed one of the most prestigious wine schools in the United States, called "Windows on the World Wine School", run by wine personality Kevin Zraly. Despite numerous assurances that these local landmarks and global attractions would be rebuilt, the Port Authority scrapped plans to rebuild these WTC attractions, which has outraged some observers.

The fortified base of the tower has been a source of controversy. A number of critics (notably Deroy Murdock of the National Review) have suggested that it is alienating and dull, and reflects a sense of fear rather than freedom, leading them to dub the project "the Fear Tower". Nicolai Ouroussoff, the architecture critic for the New York Times, calls the tower base decorations a "grotesque attempt to disguise its underlying paranoia".

America's Response Monument

The statue America's Response Monument, a life-and-a-half scale bronze monument commemorating the actions of U.S. Special Operations Forces in the first few weeks of the War in Afghanistan, was introduced to the public during the Veteran's Day Parade in New York City on November 11, 2011. The statue was displayed on a float which traveled from Fifth Ave at 23rd and north to Fifth Ave at 56th. It was dedicated the same day in a ceremony led by Vice President Joe Biden and Lt. Gen. John Mulholland, commander of Special Operations Command and formerly commander of Task Force Dagger during the initial days of the War in Afghanistan. It was temporarily located in the West Street Lobby inside One World Financial Center in New York City opposite Ground Zero.

It is the first publicly accessible monument to United States special forces. A monument commemorating the Green Berets also exists on Meadows Memorial Field at Fort Bragg, N.C. The land at One World Trade Center for the monument was donated by a private Wall Street firm.

On October 19, 2012, the monument was rededicated in front of the building. The base of the sculpture bears its title, "America's Response Monument", and the Latin subtitle De Oppresso Liber. The subtitle, traditionally translated as "to free the oppressed", is the motto of the Green Berets, by whom the monument was inspired. A piece of steel from the original World Trade Center is embedded in the base. In an uncommon move, the bronze statue is positioned so that the soldier atop the horse is looking back over his shoulder at the World Trade Center, as if keeping watch over it. The monument is dedicated to the actions of United States special forces personnel who fought as part of Operation Enduring Freedom. It is the first publicly accessible monument to American special forces personnel.

The statue was dedicated by Lieutenant General John Mulholland, Deputy Commanding General of U.S. Army Special Forces Command. Soldiers representing the United States Army Special Operations Command also attended the dedication ceremony. The land for the monument was donated by a private Wall Street firm. The statue's cost of over $750,000 was paid entirely by hundreds of private citizens, including a number of survivors of the September 11 attacks.

Owners and tenants

One World Trade Center is owned principally by the Port Authority of New York and New Jersey. Around 5 percent equity of the building was sold to the Durst Organization, a private real estate company, in exchange for an investment of at least US$100 million. The Durst Organization assisted in supervising the building's construction, and manages the building for the Port Authority, having responsibility for leasing, property management and tenant installations. By September 2012, around 55 percent of the building's floor space had been leased.

Current tenants

Government

In 2006, the State of New York agreed to a 15-year lease of 415,000 square feet (38,600 m) of space inside 1 WTC, with an option to extend the term of the lease and occupy up to 1,000,000 square feet (90,000 m). The General Services Administration (GSA) initially agreed to lease approximately 645,000 square feet (59,900 m) of space, and New York State's Office of General Services (OGS) planned to lease approximately 412,000 square feet (38,300 m) of space. However, in July 2011, the GSA ceded most of its leased floor space to the Port Authority, and the OGS withdrew from the lease agreement. In April 2008, the Port Authority announced that it was seeking a bidder to operate the 18,000 sq ft (1,700 m) observation deck on the tower's 102nd floor; in 2013, Legends Hospitality Management agreed to operate the observatory in a 15-year, $875 million deal.

Vantone China Center

The building's first lease was announced on March 28, 2009, as a joint project between the Port Authority and Beijing-based Vantone Industrial Co. A 190,810 sq ft (17,727 m) "China Center", combining business and cultural facilities, is to be located between floors 64 and 69, to represent Chinese business and cultural links to the United States, and to serve American companies that wish to conduct business in China. Vantone Industrial's lease is for 20 years and 9 months. In April 2011, a new interior design for the China Center was unveiled, featuring a vertical "Folding Garden" based on an initial proposal by the Chinese artist Zhou Wei.

Condé Nast

On August 3, 2010, Condé Nast Publications signed a tentative agreement to move the headquarters and offices of its magazines into One World Trade Center, occupying up to 1,000,000 square feet (90,000 m) of floor space. On May 17, 2011, Condé Nast reached an agreement with the Port Authority, securing a 25-year lease with an estimated value of $2 billion. On May 25, 2011, Condé Nast finalized the lease agreement, leasing 1,008,012 square feet (93,647.4 m) of office space on floors 20–41 of the tower. The lease also covers 30,000 square feet (2,800 m) of usable space in the podium and below grade floors, for mail, messenger services, and storage use. On January 17, 2012, it was reported that Condé Nast would be leasing an additional 133,000 square feet (10,000 m) of space, occupying floors 42–44 of the tower.

Prospective tenants

On January 27, 2012, it was announced that Chadbourne & Parke, a Midtown Manhattan-based law firm, would be signing a lease to around 300,000 square feet (30,000 m) of space in One World Trade Center. However, negotiations broke down and the deal failed abruptly in March 2012.

Key figures

Larry Silverstein

Larry Silverstein of Silverstein Properties, the leaseholder and developer of the complex, retains control of the surrounding buildings, while the Port Authority has full control of the tower itself. Silverstein signed a 99-year lease for the World Trade Center site in July 2001, and remains actively involved in most aspects of the site's redevelopment process. However, he was involved in an insurance dispute regarding the tower. In March 2007 Silverstein appeared at a rally of construction workers and public officials outside of an insurance industry conference to highlight what he describes as the failures of insurers Allianz & Royal and Sun Alliance to pay $800 million in claims related to the attacks. Insurers cite an agreement to split payments between Mr. Silverstein and the Port Authority as a cause for concern.

David Childs

David Childs, one of Silverstein's favorite architects, joined the project at the urging of Silverstein and developed a proposal for 1 WTC, initially in collaboration with Daniel Libeskind. The tower's design was revised by Childs in May 2005 to address security concerns. He is the project architect of the tower, and is responsible for overseeing its day-to-day design development from inception to completion.

Daniel Libeskind

Architect Daniel Libeskind won the invitational competition to develop a plan for the World Trade Center's redevelopment in 2002. He included an initial proposal, "Memory Foundations", for the design of 1 WTC, a building with aerial gardens and windmills with an off-center spire. Libeskind later denied a request to place the tower in a more rentable location next to the PATH station and instead placed it a block west, because in profile it would line up with, and resemble, the Statue of Liberty. Most of Libeskind's designs were later scrapped, and other architects were chosen to construct the other WTC buildings. Nonetheless, one element of Libeskind's initial plan was reflected in the final design – the tower's symbolic height of 1,776 feet (541 m).

Daniel and John Tishman

Daniel R. Tishman – along with his father John Tishman, builder of the original World Trade Center – led the construction management effort for Tishman Realty & Construction, the selected builder for 1 WTC.

Douglas and Jody Durst

Douglas and Jody Durst, the co-presidents of the Durst Organization, a real estate development company, won the right to invest at least $100 million in the project on July 7, 2010. The Durst Organization is a family-owned company that specializes in the development, managing, leasing, and operation of sustainable commercial construction space. Condé Nast, a long-time Durst tenant, also confirmed a tentative deal to move into 1 World Trade Center in August 2010, and finalized the deal on May 26, 2011. The contract negotiated between the Port Authority and the Durst Organization specifies that the Durst Organization will receive a $15 million fee and a percentage of “base building changes that result in net economic benefit to the project.” The specifics of the signed contract give Durst 75 percent of savings up to $24 million and stepping down thereafter (to 50 percent, 25 percent and 15 percent) as the savings increased. Since their joining the project, significant hanges have been made to the building, including the 185 foot base of the tower, the spire of the tower, and the plaza to the west of the building facing the Hudson River. The Port Authority has approved all the revisions.

Port Authority construction workers

A WoodSearch Films short-subject documentary was uploaded to YouTube on August 31, 2010, entitled How does it feel to work on One World Trade Center?. Nearly all of the construction workers interviewed praised the unity and work ethic of the new World Trade Center's construction team. Others spoke of the importance they believed the construction of the tower had to the people of the United States. A deputy foreman, George Collins, said, "All the men are working in conjunction to put this building up. They all know how important this is to the country – and to show the world what us Americans can do – and get this done, union and proud." Another deputy foreman, Scott Williams, commented, " camaraderie of the crew is very good."

In popular culture

See also

• Buildings and architecture of New York City
• List of tallest buildings in New York City
• List of buildings with 100 floors or more
• List of tallest buildings in the world
• List of tallest freestanding structures in the world
• List of tenants in One World Trade Center – Lists the tenants of the original 1 WTC, or North Tower, prior to the September 11 attacks
• One World Trade Center in popular culture
• Tallest buildings in the United States

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Further reading

• Reeve, Simon (1999). The New Jackals: Ramzi Yousef, Osama bin Laden and the Future of Terrorism. Northeastern University Press.
• Darton, Eric (1999). Divided We Stand: A Biography of New York's World Trade Center. Basic Books. ISBN 0-465-01727-4.

External links

• Official website maintained by the Durst Organization and Cushman & Wakefield
• WTC Progress – Maintained by the Port Authority of New York and New Jersey
• World Trade Center – Maintained by Silverstein Properties
• One World Trade Center on CTBUH's Skyscraper Center database
• Ground Zero Cams and 1WTC Live Cam – Live camera and time lapse photos of the WTC site
• LowerManhattan.Info – Official site for Lower Manhattan Construction Command Center
• Glass, Steel and Stone – History of Freedom Tower designs

• Buildings and structures in Manhattan
• Buildings and structures under construction in the United States
• Daniel Libeskind buildings
• Financial District, Manhattan
• Office buildings in New York City
• Skidmore, Owings & Merrill buildings
• Skyscrapers in Manhattan
• Skyscrapers over 350 meters
• World Trade Center
• 2014 in New York