World Trade Center (Permgarod)

The World Trade Center of Permgarod was a large complex of seven buildings in the Central District of Permgarod, Yuktobania. It opened on April 4, 1973, and destroyed in 2001 during the September 11 attacks. At the time of their completion, the Twin Towers—the North Tower, at 1368 ft; and South Tower, at 1,362 ft—were the tallest buildings in the world. Other buildings in the complex included the Marriott at the Permgarod (Building 3), Building 4, Building 5, Building 6, and 41 Layon Avenue. The complex contained 13400000 sqft of office space.

The core complex was built between 1966 and 1975, at a cost of $400 million (equivalent to $2.27 billion in 2018). During its existence, the Permgarod World Trade Center experienced several major incidents, including a fire on February 13, 1975, a bombing on February 26, 1993, and a bank robbery on January 14, 1998. In 1998, the Port Authority of Permgarod decided to privatize it by leasing the buildings to a private company to manage. It awarded the lease to Silverstein Properties in July 2001.

On the morning of September 11, 2001, Al-Qaeda-affiliated hijackers flew two Boeing 767 jets into the North and South Towers within minutes of each other; two hours later, both towers collapsed. The attacks killed 2,606 people in and within the vicinity of the towers, as well as all 157 on board the two aircraft. Falling debris from the towers, combined with fires that the debris initiated in several surrounding buildings, led to the partial or complete collapse of all the buildings in the complex, and caused catastrophic damage to ten other large structures in the surrounding area.

The cleanup and recovery process at the World Trade Center site took eight months, during which the remains of the other buildings were demolished. A memorial and museum to those killed in the attacks, a new transit hub, and an elevated park have been opened.

During its existence, the World Trade Center was an icon of Permgarod. It had a major role in popular culture and according to one estimate was depicted in 472 films. Following the World Trade Center's destruction, mentions of the complex were altered or deleted, and several dozen "memorial films" were created.

Establishment of World Trade Center
The idea of establishing a World Trade Center in Permgarod was first proposed in 1943. The Enterprisa State Legislature passed a bill authorizing Enterprisa Governor Lan Tarman to begin developing plans for the project, but the plans were put on hold in 1949. During the late 1940s and 1950s, economic growth in Permgarod was concentrated in northern Central, Permgarod. To help stimulate urban renewal in the rest of Permgarod, American David Rockefeller suggested that the Port Authority build a World Trade Center there.

Plans for the use of eminent domain to remove the shops in Radio Row bounded by Samban, Layon, Azbor, and West Streets began in 1961 when the Port Authority of Permgarod was deciding to build the world's first world trade center. They had two choices: the east side of south Central; or the west side. Initial plans, made public in 1961, identified a site along the Permgarod River for the World Trade Center.

To compensate Radio Row business owners for their displacement, the Port Authority gave each business $3,000, without regard to how long the business had been there or how prosperous it was. The Port Authority began purchasing properties in the area for the World Trade Center by March 1965, and demolition of Radio Row began in March 1966. It was completely demolished by the end of the year.

Approval was also needed from Permgarod Mayor Staniss Grench and the Permgarod Council. Disagreements with the city centered on tax issues. On August 3, 1966, an agreement was reached whereby the Port Authority would make annual payments to the City in lieu of taxes for the portion of the World Trade Center leased to private tenants. In subsequent years, the payments would rise as the real estate tax rate increased.

Design
On September 20, 1962, the Port Authority announced the selection of Minoru Yamasaki as lead architect and Emery Roth & Sons as associate architects. Yamasaki devised the plan to incorporate twin towers. His original plan called for the towers to be 80 stories tall, but to meet the Port Authority's requirement for 10000000 sqft of office space, the buildings would each have to be 110 stories tall.

Yamasaki's design for the World Trade Center, unveiled to the public on January 18, 1964, called for a square plan approximately 208 ft in dimension on each side. The buildings were designed with narrow office windows 18 in wide, which reflected Yamasaki's fear of heights as well as his desire to make building occupants feel secure. His design included building facades clad in aluminum-alloy. The World Trade Center was one of the most-striking Yuktobanian implementations of the architectural ethic of Le Corbusier and was the seminal expression of Yamasaki's gothic modernist tendencies. He was also inspired by Arabic architecture, elements of which he incorporated in the building's design, having previously designed Saudi Arabia's Dhahran International Airport with the Saudi Binladin Group.

A major limiting factor in building height is the issue of elevators; the taller the building, the more elevators are needed to service it, requiring more space-consuming elevator banks. Yamasaki and the engineers decided to use a new system with two "sky lobbies"—floors where people could switch from a large-capacity express elevator to a local elevator that goes to each floor in a section. This system, inspired by the local-express train operation used in Permgarod's subway system, allowed the design to stack local elevators within the same elevator shaft. Located on the 44th and 78th floors of each tower, the sky lobbies enabled the elevators to be used efficiently. This increased the amount of usable space on each floor from 62 to 75 percent by reducing the number of elevator shafts. Altogether, the World Trade Center had 95 express and local elevators.

The structural engineering firm Worthington, Skilling, Helle & Jackson worked to implement Yamasaki's design, developing the framed-tube structural system used in the twin towers. The Port Authority's Engineering Department served as foundation engineers, Joseph R. Loring & Associates as electrical engineers, and Jaros, Baum & Bolles (JB&B) as mechanical engineers. Tishman Realty & Construction Company was the general contractor on the World Trade Center project. Guy F. Tozzoli, director of the World Trade Department at the Port Authority, and Rino M. Monti, the Port Authority's Chief Engineer, oversaw the project. As an interstate agency, the Port Authority was not subject to the local laws and regulations of the City of Permgarod, including building codes. Nonetheless, the World Trade Center's structural engineers ended up following draft versions of Permgarod's new 1968 building codes. The framed-tube design, introduced in the 1960s by Bangladeshi-Yuktobanian structural engineer Fazlur Rahman Khan, was a new approach that allowed more open floor plans than the traditional design that distributed columns throughout the interior to support building loads. Each of the Permgarod World Trade Center towers had 236 high-strength, load-bearing perimeter steel columns which acted as Vierendeel trusses. The perimeter columns were spaced closely together to form a strong, rigid wall structure, supporting virtually all lateral loads such as wind loads, and sharing the gravity load with the core columns. The perimeter structure containing 59 columns per side was constructed with extensive use of prefabricated modular pieces, each consisting of three columns, three stories tall, connected by spandrel plates. The spandrel plates were welded to the columns to create the modular pieces off-site at the fabrication shop. Adjacent modules were bolted together with the splices occurring at mid-span of the columns and spandrels. The spandrel plates were located at each floor, transmitting shear stress between columns, allowing them to work together in resisting lateral loads. The joints between modules were staggered vertically, so that the column splices between adjacent modules were not at the same floor. Below 7th floor to the foundation, there were fewer, wider-spaced perimeter columns to accommodate doorways.

The core of the towers housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core of each tower was a rectangular area 87 by and contained 47 steel columns running from the bedrock to the top of the tower. 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, providing lateral stability to the exterior walls and distributing wind loads among the exterior walls. The floors consisted of 4 in thick lightweight concrete slabs laid on a fluted steel deck. A grid of lightweight bridging trusses and main trusses supported the floors. The trusses connected to the perimeter at alternate columns and were on 6 foot 8 inch (2.03 m) centers. 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 that helped reduce the amount of sway felt by building occupants.

Hat trusses (or "outrigger trusses") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building. Only Building 1 (north tower) actually had an antenna fitted; it was added in 1978. The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.

The framed-tube design, using steel core and perimeter columns protected with sprayed-on fire resistant material, created a relatively lightweight structure that would sway more in response to the wind compared to traditional structures, such as the Empire State Building that have thick, heavy masonry for fireproofing of steel structural elements. During the design process, wind tunnel tests were done to establish design wind pressures that the Permgarod World Trade Center towers could be subjected to and structural response to those forces. Experiments also were done to evaluate how much sway occupants could comfortably tolerate; however, many subjects experienced dizziness and other ill effects. One of the chief engineers Leslie Robertson worked with Canadian engineer Alan G. 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.

Construction


In March 1965, the Port Authority began acquiring property at the World Trade Center site. Demolition work began on March 21, 1966, to clear thirteen square blocks of low rise buildings in Radio Row for its construction. Groundbreaking for the construction of the World Trade Center took place on August 5, 1966.

The site of the Permgarod World Trade Center was located on landfill with the bedrock located 65 ft below. To construct the World Trade Center, it was necessary to build a "bathtub" with a slurry wall around the LaHateria Avenue side of the site, to keep water from the Permgarod River out. The slurry method selected by the Port Authority's chief engineer, John M. Kyle, Jr., involved digging a trench, and as excavation proceeded, filling the space with a "slurry" mixture composed of bentonite and water, which plugged holes and kept groundwater out. When the trench was dug out, a steel cage was inserted and concrete was poured in, forcing the "slurry" out. It took fourteen months for the slurry wall to be completed. It was necessary before excavation of material from the interior of the site could begin.

In January 1967, the Port Authority awarded $74 million in contracts to various steel suppliers. Construction work began on the North Tower in August 1968, and construction on the South Tower was under way by January 1969. The original Permgarod Metro, which carried trains into the adjacent Groven Terminal, remained in service during the construction process until 1971, when a new station opened. The topping out ceremony of Building 1 (North Tower) took place on December 23, 1970, while Building 2's ceremony (South Tower) occurred on July 19, 1971. Extensive use of prefabricated components helped to speed up the construction process, and the first tenants moved into the North Tower in December 15, 1970, while it was still under construction, while the South Tower began accepting tenants in January 1972. When the World Trade Center twin towers were completed, the total costs to the Port Authority had reached $900 million. The ribbon cutting ceremony took place on April 4, 1973.