The Seven Wonders of The Modern World
1. The Empire State Building,
New York City
Construction of the Empire State Building began in March of 1930 on the site
of the old Waldorf-Astoria Hotel at 350 Fifth Avenue at 34th Street. It was
completed 14 months later in May, 1931. Designed by the architectural firm of
Shreve, Lamb, & Harmon Associates, the Empire State Building, at 102 stories,
was the tallest building in the world until the completion of the first tower of
the World Trade Center in Lower Manhattan in 1972.
350 Fifth Avenue, between 33rd and 34th Streets, New York, NY 10001
Architects: Shreve, Lamb & Harmon Associates.
Builders: Starrett Brothers & Eken, Inc.
Height: 1,472 feet (448 meters) to top of antennae. 1,250 feet (391
meters) to 102nd floor observatory. 1,050 feet (320 meters) to 86th floor
Volume: 37 million cubic feet.
Area of Site: 83,860 square feet.
Cost including land: $40,948,900. (451,173,508 in today's money)
Cost of building alone: $24,718,000 (272,342,000 in today's money)
Excavation: Begun January 22, 1930, before demolition of old Waldorf-Astoria
Construction: Begun March 17, 1930. Framework rose at the rate of 4.5
stories per week.
Cornerstone: Laid by Alfred E. Smith, former governor of New York, September
Masonry completed: November 13, 1930.
Official opening: May 1, 1931, by President Herbert Hoover, who
pressed a button in Washington, D.C. to turn on the building's lights.
Total time: 7 million man hours, 1 year and 45 days work, including
Sundays and holidays.
Work Force: 3,400 during peak periods.
Exterior: Indiana limestone and granite, trimmed with aluminum and
chrome-nickel steel from the 6th floor to the top.
Interior lobby: Ceiling high marble, imported from France, Italy, Belgium
2. The Itaipu Dam, Paraná River
The Itaipú hydroelectric power plant is the largest development of
its kind in operation in the world. Built from 1975 to 1991, in a binational
development on the Paraná River, Itaipú
represents the efforts and accomplishments of two neighboring countries, Brazil
and Paraguay. The power plant's 18 generating units add up to a total production
capacity of 12,600 MW (megawatts) and a reliable output of 75 million MWh a
year. Itaipú's energy production has broken several records over the recent
years, after the last generating unit was commissioned in 1991. The generation
of 77.212.396 MWh a year in 1995 will again be surpassed in 1996, and the new
record will be around the 80 million MWh a year mark.
The magnitude of the project can also be demonstrated by
the fact that in 1995 Itaipú alone responded for 25% of the energy supply in
Brazil and 78% in Paraguay. The power plant is also a major tourism
attraction in the Foz do Iguaçú area, having received around 9 million
visitors from 162 countries. The Brazilian city of Foz do Iguaçu, also home
of the famous Iguaçú Falls, is located at the Western tip of Paraná State,
right by the border with Paraguay and Argentina.
General Outline of the Project
The Itaipú hydroelectric power
plant, located 14 kilometers North of the International Bridge linking the
cities of Foz do Iguaçú, Brazil, and Ciudad del Este, Paraguay, consists of
a series of various types of dams a total distance of 7,744 meters with a
crest elevation of 225 meters. The Powerhouse is located at the toe of the
main Dam, most of it on the river bed and the rest on the Diversion Channel.
The nominal power of the plant is 12,600 MW, divided between 18 generating
units of 700 MW each, 15 of which are located in the main Powerhouse and the
remaining three on the Diversion Channel. The Spillway is located on the
right bank, and it has 14 segmented sluice-gates with a total discharge rate
of 62,200 cubic meters per second (twice that of the highest flood- level on
record). The Concrete Main Dam is of the hollow gravity type and is
connected to the Spillway by a concrete buttress-type Wing Dam which
continues thereon as a small Cardhfill dike. On the left bank a Rockfill Dam
is linked to the Main Dam and at the other end to an Earthfill Dam. In order
to build the main dam wall and the Powerhouse, the river was diverted
through a Diversion Channel on the left bank.
The volumes of construction in Itaipú are also
impressive. The volume of iron and steel utilized in the Dam structure would
be enough to build 380 Eiffel Towers, and the volume of concrete used in
Itaipú represents 15 times the volume utilized to build the Channel Tunnel
between France and England. Itaipú is one of the Seven Wonders of the Modern
World, according to a worldwide survey conducted by the American Society of
civil Engineers (ASCE).To build the Itaipú Dam, workers reenacted a labor of
Hercules: they shifted the course of the seventh biggest river in the world
(Paraná River, at the Brazil/Paraguay border) and removed more than 50
million tons of earth and rock. The true marvel of Itaipú, though, is its
powerhouse ... a single building that puts out 12,600 megawatts -- enough to
power most of California".
3. The CN Tower, Toronto
It is fitting that
television, the technological wonder that profoundly changed life in the
20th century, spurred the building of the era's tallest freestanding
structure. In the late 1960's, Toronto's soaring skyline began to play havoc
with signals from conventional transmission towers. Signals bouncing off the
city's skyscrapers produced a number of problems, including the annoying
phenomenon of "ghosting" on television sets. Weaker signals competed with
stronger ones, giving viewers the effects of watching two programs at once.
To improve the situation, Canadian National Railways, or CN, proposed
building a transmission tower that would stand head and shoulders - and then
some - above Toronto's tallest buildings.
A Toronto firm prepared the initial design, enlisting the aid
of engineering experts the world over. Their original plan showed three towers
linked by structural bridges. Gradually the design evolved into a single
1,815.5-foot-tall tower comprised of three hollow "legs." Foundation work began
in 1973. Giant backhoes excavated more than 62,000 tons of earth and shale to a
depth of 50 feet from a along the shore of Lake Ontario in Toronto harbour.
Next, prestressed concrete and reinforced steel were arranged in a Y-shaped
pattern 22 feet thick. Each hollow leg of the Y would carry its fair share of
the tower's 130,000-ton burden.
The foundation took only four months to complete. The
tower itself presented a challenge of height never before met by the
technique of poured concrete. To meet that challenge, engineers designed a
huge mold known as a slip form. Concrete was poured 24 hours a day, five
days a week, and as it hardened, the mold moved upward by means of a ring of
hydraulic jacks. The ascending slip form gradually decreased in girth to
give the tower its tapering shape. When the tower reached the 1,100-foot
mark, the builders made preparations for the SkyPod, a seven-story structure
housing two observation decks, a revolving restaurant, a nightclub, and
broadcasting equipment. The SkyPod is anchored by 12 steel-and-wooden
brackets that were slowly pushed up the tower by 45 hydraulic jacks.
Concrete formed the SkyPod's "walls," and a doughnut-shaped ring, called a
radome, was added to its base to protect the delicate microwave dishes
receiving radio and television transmissions. The SkyPod is reached by four
high-speed, glass-fronted elevators whose rapid rise simulates a jetliner's
takeoff, unless weather conditions call for a much slower ascent.
The concrete tower continues above the SkyPod, ending at
the Space Deck 1,465 feet up. The Space Deck receives support from
cantilevers extending out of the concrete section beneath it. After a
58-second elevator ride from the SkyPod below, visitors can enjoy
breathtaking vistas from a glass-enclosed balcony. On a clear day they might
be able to glimpse sites 75 miles away. For the last phase of construction,
a Sikorsky Skycrane helicopter arrived to install the tower's 335-foot
communications mast. One by one the helicopter lifted about 40 seven-ton
sections of the mast to the top of the tower, where workers braved blustery
March winds to receive them. When the sections were in place, they were
secured by a total of 40,000 bolts. Afterward, the entire mast was covered
by a fiberglass-reinforced sheathing to prevent icing.
Of interest to Torontonians since construction began, the
CN tower gained additional fans with the arrival of the helicopter.
Nicknamed Olga, its daily schedule was printed in newspapers, and changes
were announced as breaking news on radio and television. With Olga, the mast
assembly took a little longer than three weeks; without Olga, the job would
have lasted six months. Completed in 1975, the tower had cost $57 million
(236,216,000 in today's money) to build, a bargain compared with other
modern wonders. It also boasted incredible statistics of precision and
safety. During construction, surveyors' transits up to a thousand feet away
focused on optical plumbs mounted on the slip-form base. The constant
surveillance kept the structure an incredible 1.1 inches within plumb.
Engineers established a wind-tolerance standard for the
tower of 260 miles an hour, a level well above nature's most extreme
demands. Counterweights on the antenna correct for wobble in high winds.
Because the tower is an easy target for lightning, copper grounding wires
were installed. As a result, visitors can safely view some 75 spectacular
strikes a year. The CN Tower is a work in progress. In recent years the
tower gained two new elevators to accommodate an increase in visitors. To
accomplish this, the 2,579-step metal staircase was moved to the interior of
the structure. In addition, a glass floor was added to the SkyPod's
observation deck. Brave visitors, the majority not surprisingly children,
inch out over the visual void. More often than not the experience is
pronounced, "Awesome!" Almost twice as tall as the Eiffel Tower and more
than three times the height of the Washington Monument, the CN Tower has
taken proud ownership of Toronto's skyline, while exorcising the ghosts from
its TV sets.
4. The Panama Canal, Panama
Among the great peaceful endeavors of mankind that have
contributed significantly to progress in the world, the construction of the
Canal stands as an awe-inspiring achievement. The unparalled engineering
triumph was made possible by an international work force under the
leadership of American visionaries, who made the centuries-old dream of
uniting the two great oceans a reality. In 1534, Charles I of Spain ordered
the first survey of a proposed canal route through the Isthmus of Panama.
More than three centuries passed before the first construction was started.
The French labored 20 years, beginning in 1880, but disease and financial
problems defeated them.
In 1903, Panama and the United States signed a treaty by
which the United States undertook to construct an inter-oceanic ship canal
across the Isthmus of Panama. The following year, the United States
purchased from the French Canal Company its rights and properties for $40
million and began construction. The monumental project was completed in ten
years at a cost of about $387 million (7,192,727,272 in today's money)..
Since 1903 the United States has invested about $3 billion in the Canal
enterprise, approximately two-thirds of which has been recovered. The
building of the Panama Canal involved three main problems -- engineering,
sanitation, and organization. Its successful completion was due principally
to the engineering and administrative skills of such men as John F. Stevens
and Col. George W. Goethals, and to the solution of extensive health
problems by Col. William C. Gorgas. The engineering problems involved
digging through the Continental Divide; constructing the largest earth dam
ever built up to that time; designing and building the most massive canal
locks ever envisioned; constructing the largest gates ever swung; and
solving environmental problems of enormous proportions.
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