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1973:
World Trade Center History
When they debuted in 1973, the two glistening 110-story towers of New
York City's World Trade Center
(WTC), 1,362 and 1,368 ft high, were more than 100 ft taller than the
city's other world height record holder—the Empire State Building. Their
size was the subject of a joke during the press conference to unveil
the landmarks. WTC architect Minoru Yamasaki was asked: "Why two 110-story
buildings? Why not one 220-story building?" His tongue-in-cheek answer:
"I didn't want to lose the human scale."
But the Towers were not always popular. A World Trade Center was first
proposed in 1960 by the Downtown-Lower Manhattan Development Association
to revitalize seedy "radio row," dominated by electronic stores. Chase
Manhattan Bank Chairman David Rockefeller, founder of the development
association, and his brother, Nelson, New York governor, pushed hard
for the project, insisting it would benefit the entire city.
In 1962, the Port Authority of New York and New Jersey began plans to
build the center. Minoru Yamasaki and Associates of Michigan, and Emery
Roth & Sons, P.C., were hired as architects. Eventually, Yamasaki decided
on two huge towers. Critics charged that a modern monolith would rob
New York of character, ruin the skyline, disrupt television reception,
and strain city services.
However, the project was approved and construction began in 1965.
Five streets were closed off and 164 buildings demolished to create
the 16-acre site. Construction required the excavation of more than
1.2 million cubic yards of earth which created 23.5 acres of land along
the Hudson River, now Battery City Park, a complex of four 60-story
skyscrapers and four apartment buildings.
Before foundation excavation began, the 500 x 1,000-ft site was enclosed by a 3-ft-thick, 70-ft-high concrete cutoff wall built by the slurry trench wall method and keyed 3 ft into rock. Excavation was complicated by two nearby subways that had to be supported without service interruption. A six-level basement was built in the foundation hole. Excavation of 1.2 million cu yd of earth and rock created $90 million of real estate for project owner, the Port of New York Authority. Instead of being trucked off for disposal, spoil was used to create 23 acres of fill in the Hudson River adjacent to the WTC site. It has since been developed as Battery Park City.
The twin towers had the world's highest load-bearing walls. Seattle-based structural engineer Worthington, Skilling, Helle and Jackson designed them as vertical cantilevered steel tubes. Exterior columns were 14-in. square hollow box sections spaced 39 in. center-to-center.
Installation of steel for the load-bearing walls was a problem of logistics. Adjacent city streets were narrow, congested and offered little storage space. Each of the 200,000 pieces of steel had to arrive at the right place at the right time—and for the most part, they did. One of the industry's earliest computer-programmed control systems, which took the owner's engineers six months to set up, helped accomplish this. The twin towers' HVAC system circulated and filtered 9 million cu ft of air per minute to more than 9 million sq ft of office space. Air conditioning was provided by a 2.5-acre refrigeration plant at the fourth basement level. Instead of cooling towers, intake and outflow pipes ran to the river, only 150 ft away.
During peak construction periods, 3,500 people worked at the site. A total of 10,000 people worked on the towers' construction and 60 died in the project which involved more than 700 contracts, coordinated and administered by Tishman Realty and Construction Co., New York City.
They were
the world's tallest buildings for only a short time, since the Sears
Tower in Chicago, which would reach 1,450 ft, was dedicated a month
later. However, the north tower sported a 360-foot television mast that
allowed it to technically remain the world's tallest building. A hotel,
a shopping plaza, and three smaller buildings nearby completed the complex.
Life
in the Towers
Shopping
malls with restaurants, stores, and barbershops dotted the concourses.
The mall underneath the towers contained another 75 stores. The six
basements also included two New York subway stations and the PATH trains
to New Jersey, used by 150,000 people daily.
Some 50,000 people worked in the buildings, while another 200,000 visited
or passed through each day. The top floor observation deck had 26,000
visitors daily, who could see for 45 miles on a clear day. From the
ground, the towers were visible for at least 20 miles.
The 43,600 windows were washed automatically, while the air conditioning system was the world's largest, with 60,000 tons of cooling capacity. It took 250,000 cans of paint each year to spruce up the towers.
Each tower had 97 elevators for passengers and six for freight. Express elevators zoomed skyward at 27 feet per second, reaching the top in 4.8 minutes. More than 300 computer main frames in the towers served the towers' occupants.
In 1976, the elegant Windows on the World restaurant opened at the top of the north tower, followed by Cellar in the Sky. The top floor restaurants attracted such performers as Frank Sinatra, John Lennon, Liza Minnelli, and Mick Jagger. Far below, restaurants in the basement concourse served 30,000 cups of coffee each day, while 87 tons of food was delivered to the towers daily.
Before their collapse, 19 murders were committed and 17 babies born in the towers. They also contained nine chapels representing six different faiths.
As the towers became more famous, they attracted daredevils. Three men parachuted from the top, while one dozen mountain climbers scaled the outside. In 1974 a Frenchman walked a tightrope between the towers.
The twin towers became the most popular postcard image in the world. Some three-dozen movies were made at the towers, including the 1976 remake of King Kong.
The
End
In
1993, terrorists drove a truck packed with 1,100 pounds of explosives
into the basement parking garage at the World Trade Center. Despite
the size of the blast, only six people were killed and 1,000 injured.
After that bombing, the number of parking spaces in the basement garage
was reduced from 1,000 to 600.
Security in the buildings was considerable. The lobby in each building
had 12 X-ray machines and 16 concierge desks. The towers employed over
300 security personnel, used 300 security cameras, and featured 828
emergency doors.
The World Trade Center Twin Towers collapsed after 2 planes crashed against them on September 11th, 2001, during a terrorist attack that caused the deaths of more than 5000 people.
-The World Trade Center had two 110-story buildings, known as the "Twin Towers" and five smaller buildings.
-Tower One was 1,368 feet (414 meters) tall
-Tower Two was 1,362 feet (412 meters) tall
-Architects: Minoru Yamaski & Associates and Emery, Roth & Sons.
-The Twin Towers were the tallest until the Sears Tower surpassed them.
-About 50,000 people worked in the complex, which housed the offices of more than 430 businesses from 26 countries and 9 chapels of 6 different faiths.
-Each tower consisted of 104 passenger elevators and 21,800 windows.
-Automatic window-washing machines cleaned 600,000 square feet of glass.
-The foundation of each tower extended more than 70 feet below ground, resting on solid bedrock and was visible for 20 miles from ground
–Had its own zip code, 10048
–Had 110 floors
-The towers were the best known examples of "tube buildings," which are strenghtened by closely spaced columns and beams in the outer walls.
-Constructed on six acres of landfill
-Built
of aluminum and 200,000 tons of steel
–425,000 cubic yards of concrete
–600,000 square feet of glass
–12,000 miles of electric cables
–Weighed 1.5 million tons
–Contained 198 miles of heating ducts
–Used 23,000 fluorescent light bulbs
Sources:
Engineering news record, Bentley, World Trade Center, David Johnson,
Dan Heller and PBS .
