There is no precise definition of how many stories or what height makes a building a skyscraper. "I don't think it is how many floors you have. I think it is attitude," architect T. J. Gottesdiener told the Christian Science Monitor. Gottesdiener, a partner in the firm of Skidmore, Owings & Merrill, designers of numerous tall buildings including the Sears Tower in Chicago, Illinois, continued, "What is a skyscraper? It is anything that makes you stop, stand, crane your neck back, and look up."
Some observers apply the word "skyscraper" to buildings of at least 20 stories. Others reserve the term for structures of at least 50 stories. But it is widely accepted that a skyscraper fits buildings with 100 or more stories. At 102 stories, the Empire State Building's in New York occupied height reaches 1,224 ft (373 m), and its spire, which is the tapered portion atop a building's roof, rises another 230 ft (70 m). Only 25 buildings around the world stand taller than 1,000 ft (300 m), counting their spires, but not antennas rising above them.
The tallest freestanding structure in the world is the CN Tower in Toronto, Canada, which rises to a height of 1,815 ft (553 m); constructed to support a television antenna, the tower is not designed for human occupation, except for a restaurant and observation deck perched at 1,100 ft (335 m). The world's tallest occupied structure is the Petronas Twin Towers in Kuala Lumpur, Malaysia, which reach a height of 1,483 ft (452 m), including spires. The Sears Tower in Chicago boasts the highest occupied level; the roof of its 110th story stands at 1,453 ft (443 m).
In some ways, super-tall buildings are not practical. It is cheaper to build two half-height buildings than one very tall one. Developers must find tenants for huge amounts of space at one location; for example, the Sears Tower encloses 4.5 million square feet (415,000 square meters). On the other hand, developers in crowded cities must make the fullest possible use of limited amounts of available land. Nonetheless, the decision to build a dramatically tall building is usually based not on economics, but on the desire to attract attention and gain prestige.
Several technological advances occurred in the late nineteenth century that combined to make skyscraper design and construction possible. Among them were the ability to mass produce steel, the invention of safe and efficient elevators, and the development of improved techniques for measuring and analyzing structural loads and stresses. During the 1920s and 1930s, skyscraper development was further spurred by invention of electric arc welding and fluorescent light bulbs (their bright light allowed people to work farther from windows and generated less heat than incandescent bulbs).
Traditionally, the walls of a building supported the structure; the taller the structure, the thicker the walls had to be. A 16-story building constructed in Chicago in 1891 had walls 6 ft (1.8 m) thick at the base. The need for very thick walls was eliminated with the invention of steel-frame construction, in which a rigid steel skeleton supports the building's weight, and the outer walls are merely hung from the frame almost like curtains. The first building to use this design was the 10-story Home Insurance Company Building, which was constructed in Chicago in 1885.
The 792-ft (242-m) tall Woolworth Building, erected in New York City in 1913, first combined all of the components of a true skyscraper. Its steel skeleton rose from a foundation supported on concrete pillars that extended down to bedrock (a layer of solid rock strong enough to support the building), its frame was braced to resist expected wind forces, and its high-speed elevators provided both local and express service to its 60 floors.
In 1931, the Empire State Building rose in New York City like a 1,250-ft (381-m) exclamation point. It would remain the world's tallest office building for 41 years. By 2000, only six other buildings in the world would surpass its height.
Reinforced concrete is one important component of skyscrapers. It consists of concrete (a mixture of water, cement powder, and aggregate consisting of gravel or sand) poured around a gridwork of steel rods (called rebar) that will strengthen the dried concrete against bending motion caused by the wind. Concrete is inherently strong under compressive forces; however, the enormous projected weight of the Petronas Towers led designers to specify a new type of concrete that was more than twice as strong as usual. This high-strength material was achieved by adding very fine particles to the usual concrete ingredients; the increased surface area of these tiny particles produced a stronger bond.
The other primary raw material for skyscraper construction is steel, which is an alloy of iron and carbon. Nearby buildings often limit the amount of space available for construction activity and supply storage, so steel beams of specified sizes and shapes are delivered to the site just as they are needed for placement. Before delivery, the beams are coated with a mixture of plaster and vermiculite (mica that has been heat-expanded to form sponge-like particles) to protect them from corrosion and heat. After each beam is welded into place, the fresh joints are sprayed with the same coating material. An additional layer of insulation, such as fiberglass batting covered with aluminum foil, may then be wrapped around the beams.
To maximize the best qualities of concrete and steel, they are often used together in skyscraper construction. For example, a support column may be formed by pouring concrete around a steel beam.
A variety of materials are used to cover the skyscraper's frame. Known as "cladding," the sheets that form the exterior walls may consist of glass, metals, such as aluminum or stainless steel, or masonry materials, such as granite, marble, or limestone.
Design engineers translate the architect's vision of the building into a detailed plan that will be structurally sound and possible to construct.
Designing a low-rise building involves creating a structure that will support its own weight (called the dead load) and the weight of the people and furniture that it will contain (the live load). For a skyscraper, the sideways force of wind affects the structure more than the weight of the building and its contents. The designer must ensure that the building will not be toppled by a strong wind, and also that it will not sway enough to cause the occupants physical or emotional discomfort.
Each skyscraper design is unique. Major structural elements that may be used alone or in combination include a steel skeleton hidden behind non-load-bearing curtain walls, a reinforced concrete skeleton that is in-filled with cladding panels to form the exterior walls, a central concrete core (open column) large enough to contain elevator shafts and other mechanical components, and an array of support columns around the perimeter of the building that are connected by horizontal beams to one another and to the core.
Because each design is innovative, models of proposed super tall buildings are tested in wind tunnels to determine the effect of high wind on them, and also the effect on surrounding buildings of wind patterns caused by the new building. If tests show the building will sway excessively in strong winds, designers may add mechanical devices that counteract or restrict motion.
In addition to the superstructure, designers must also plan appropriate mechanical systems such as elevators that move people quickly and comfortably, air circulation systems, and plumbing.
The Construction Process
Each skyscraper is a unique structure designed to conform to physical constraints imposed by factors like geology and climate, meet the needs of the tenants, and satisfy the aesthetic objectives of the owner and the architect. The construction process for each building is also unique. The following steps give a general idea of the most common construction techniques.
- 1 Construction usually begins with digging a pit that will hold the foundation. The depth of the pit depends on how far down the bedrock lies and how many basement levels the building will have. To prevent movement of the surrounding soil and to seal out water from around the foundation site, a diaphragm wall may be constructed before the pit is dug. This is done by digging a deep, narrow trench around the perimeter of the planned pit; as the trench is dug, it is filled with slurry (watery clay) to keep its walls from collapsing. When a section of trench reaches the desired depth, a cage of reinforcing steel is lowered into it. Concrete is then pumped into the trench, displacing the lighter slurry. The slurry is recovered and used again in other sections of the trench.
- 2 In some cases, bedrock lies close to the surface. The soil on top of the bedrock is removed, and enough of the bedrock surface is removed to form a smooth, level platform on which to construct the building's foundation. Footings (holes into which the building's support columns can be anchored) are blasted or drilled in the bedrock. Steel or reinforced concrete columns are placed in the footings.
- 3 If the bedrock lies very deep, piles (vertical beams) are sunk through the soil until they are embedded in the bedrock. One technique involves driving steel piles into place by repeatedly dropping a heavy weight on their tops. Another technique involves drilling shafts through the soil and into the bedrock, inserting steel reinforcing rods, and then filling the shafts with concrete.
- 4 A foundation platform of reinforced concrete is poured on top of the support columns.
The superstructure and core
Once construction of a skyscraper is underway, work on several phases of the structure proceeds simultaneously. For example, by the time the support columns are several stories high, workers begin building floors for the lower stories. As the columns reach higher, the flooring crews move to higher stories, as well, and finishing crews begin working on the lowest levels. Overlapping these phases not only makes the most efficient use of time, but it also ensures that the structure remains stable during construction.
- 5 If steel columns and cross-bracing are used in the building, each beam is lifted into place by a crane. Initially, the crane sits on the ground; later it may be positioned on the highest existing level of the steel skeleton itself. Skilled workers either bolt or weld the end of the beam into place (rivets have not been used since the 1950s). The beam is then wrapped with an insulating jacket to keep it from overheating and being weakened in the event of a fire. As an alternative heat-protection measure in some buildings, the steel beams consist of hollow tubes; when the superstructure is completed, the tubes are filled with water, which is circulated continuously throughout the lifetime of the building.
- 6 Concrete is often used for constructing a building's core, and it may also be used to construct support columns. A technique called "slip forming" is commonly used. Wooden forms of the desired shape are attached to a steel frame, which is connected to a climbing jack that grips a vertical rod. Workers prepare a section of reinforcing steel that is taller than the wooden forms. Then they begin pouring concrete into the forms. As the concrete is poured, the climbing jack slowly and continuously raises the formwork. The composition of the concrete mixture and the rate of climbing are coordinated so that the concrete at the lower range of the form has set before the form rises above it. As the process continues, workers extend the reinforcing steel grid that extends above the formwork and add extensions to the vertical rod that the climbing jack grips. In this way, the entire concrete column is built as a continuous vertical element without joints.
- 7 In a steel-skeleton building, floors are constructed on the layers of horizontal bracing. In other building designs, floors are supported by horizontal steel beams attached to the building's core and/or support columns. Steel decking (panels of thin, corrugated steel) is laid on the beams and welded in place. A layer of concrete, about 2-4 in (5-10 cm) thick, is poured on the decking to complete the floor.
The Empire State Building was intended to end the competition for tallest building. It was to tower 102 stories, 1,250 ft (381 m) above Manhattan's streets. Its developers, John J. Raskob and Pierre Samuel Du Pont, along with former New York Governor Alfred E. Smith, announced in August 1929 their intention to build the world's tallest building. They chose the construction firm Starrett Brothers and Eken, and the architectural firm Shreve, Lamb, and Harmon for the project with William F. Lamb as the chief designer. If is set back from the street above the fifth floor and then soars uninterrupted for more than 1,000 ft (305 m) to the 86th floor. The exterior is limestone and granite and vertical chrome-nickel-steel alloy columns extend from the sixth floor to the top. The building contained 67 elevators and 6,500 glass windows, topped with a 200-ft (61-m) mooring mast for dirigibles.
The Empire State Building was completed on April 11, 1931, 12 days ahead of schedule and officially opened on May 1, 1931. The building took its place in history as the tallest building ever built, holding this title for more than 40 years. It was not until 1972, when the 1,348-ft-(411-m-) tall twin towers of the World Trade Center were completed that the Empire State Building was surpassed in height. The World Trade Center in turn was surpassed in 1974 by the Sears Tower in Chicago, which at 1,453 ft (443 mj became the tallest building in the world.
- 8 In most tall buildings, the weight of the structure and its contents is borne by the support columns and the building's core. The exterior walls themselves merely enclose the structure. They are constructed by attaching panels of such materials as glass, metal, and stone to the building's framework. A common technique is to bolt them to angle brackets secured to floor slabs or support columns.
- 9 When a story of the building has been enclosed by exterior walls, it is ready for interior finishing. This includes installation of such elements as electrical wires, telephone wires, plumbing pipes, interior walls, ceiling panels, bathroom fixtures, lighting fixtures, and sprinkler systems for fire control. It also includes installation of mechanical components like elevators and systems for air circulation, cooling, and heating.
- 10 When the entire superstructure has been completed, the top of the building is finished by installing a roof. This may be built much like a floor, and then waterproofed with a layer of rubber or plastic before being covered with an attractive, weather—resistant layer of tiles or metal.
Various factors are taken into consideration when assuring quality control. Because of the huge scale of skyscrapers, a small positioning error at the base will be magnified when extended to the roof. In addition to normal surveying instruments, unusual devices like global positioning system (GPS) sensors and aircraft bombsights may be used to verify the placement and alignment of structural members.
Soil sensors around the building site are used to detect any unexpected earth movement caused by the construction activity.
Excavation of the foundation pit and basement levels require the removal of enormous amounts of dirt. When the 110-story World Trade Center towers were built in New York in the early 1970s, more than I million cubic yards (765,000 cubic meters) of soil and rock were removed and dumped in the Hudson River to create 23.5 acres (95,100 square meters) of new land, on which another skyscraper was later constructed.
Plans have been developed for several new skyscrapers that would break existing height records. For example, a 108-story building at 7 South Dearborn Street in Chicago, expected to be completed by 2004, will be 1,550 ft (473 m) tall. It will provide 43 acres (174,000 square meters) of enclosed space on a lot only 200 ft (61 m) square.
In 1956, American architect Frank Lloyd Wright announced plans for a mile-high (1.6-km tall) skyscraper in which 100,000 people could work. In 1991, another American architect, Dr. Eugene Tsui, designed a 2-mile (3,220-m) tall building that would provide space for living, working, and recreation for 1,000,000 people. Although such buildings may be theoretically constructable, they are currently impractical. For example, human comfort levels limit elevator speeds to no more than 3,000 ft/min (915 m/min). To accommodate the 100,000 people working in Wright's proposed structure, the number of elevator shafts would have taken up too large a portion of the building's area.
Improvements in elevator technology will be important for future skyscraper designs. Self-propelled, cableless elevator cars that move horizontally, as well as vertically, have been proposed, but are still under development. Computerized car dispatching systems using fuzzy logic could be refined to carry people more efficiently by grouping passengers whose destinations are near each other.
Where to Learn More
Books Dunn, Andrew. Structures: Skyscrapers. New York: Thomson Learning, 1993.
Michael, Duncan. How Skyscrapers Are Made. New York: Facts on File Publications, 1987.
Hayashi, Alden M. "The Sky's the Limit." Scientific American Presents: Extreme Engineering (Winter 1999): 66 ff.
Richey, Warren. "New Rush of Buildings Reaching for the Clouds." The Christian Science Monitor (July 8, 1998): 1.
Dankwa, E. T. New York Skyscrapers.http://mx3.xoom.com/iNetwork/NYC (March 2000).
"Ultima's Tower, Two-Mile High Sky City." Tsui Design & Research.http://www.tdrinc.com/ultima.html (March 2000).
"Skyscraper." How Products Are Made. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/skyscraper
"Skyscraper." How Products Are Made. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/skyscraper
SKYSCRAPERS entered American parlance around 1890, describing ten-to fifteen-story commercial buildings mostly in Chicago and New York. Dependent on the passenger elevator, telephone, and incandescent bulb for internal circulation, communication, and illumination, the structural potential of its steel frame ensured that the economic benefit of multiplying lot size twenty, fifty, or one hundred times would render municipal height restrictions obsolete. Well before New York's 1913 Woolworth Building opened at 792 feet (54 stories), the world's tallest edifice excepting the Eiffel Tower in Paris, it was a social convention to wonder if the only limit to upward growth were the heavens themselves.
Artistic hesitation characterized skyscraper design from the beginning, less so in Chicago than in New York. Although skyscrapers' determining features were steel and height, architects were inclined to hide steel inside highly decorated, thick masonry walls. In addition, they negated height by wrapping every few stories with a protruding cornice interrupting vertical flow or by periodically shifting styles, so, as a building ascended, it resembled a stack of small structures. Those willing to embrace height tended to base form on historical analogies, usually French gothic cathedrals or Italian medieval towers.
In Chicago, Louis Sullivan referred to the classical column, but in his pioneering search for a self-referential skyscraper aesthetic, he transformed base, shaft, and capital into commercial ground floor, office tier, and attic for ancillary services, each function indicated externally. By recessing windows and walls a few inches behind columns and mullions, he privileged vertical elements of the frame to create, he wrote in 1896, "a proud and soaring thing" that was "every inch of it tall." Although highly regarded by critics, Sullivan's "system of vertical construction" was not widely adopted by architects, not even his Chicago School (c. 1885–1915) colleagues, whose so-called "utilitarian" building facades, less ornamented and more fenestrated than Sullivan's, closely followed in composition the grid pattern of the frame, which in reality is nondirectional.
Chicago School buildings were America's principal contribution to the formative stages of what was soon labeled "modern architecture." The implication, which might be encapsulated in the phrase "form follows structure," was disregarded in the United States during the 1920s, but it was taken up in Europe, particularly in Germany,
where in 1921 and 1922 Ludwig Mies van der Rohe proposed free-form skyscrapers entirely encased with glass panels clipped to the edges of floor slabs. Of the 265 entries from 23 countries to the 1922 Chicago Tribune headquarters competition, 37 were German, notable among them Walter Gropius and Adolf Meyer's grid of reinforced concrete completely filled with windows. These and other European designs conclusively demonstrated what Chicagoans had almost perceived. Since load-bearing walls were structurally unnecessary, a skyscraper's facade could be reduced to little more than frame and glazing. The lesson was ignored when the Tribune Company selected Raymond Hood and John Mead Howells's decidedly unglassy, neogothic cousin to the Woolworth Building.
Until large-scale private sector construction halted during the Great Depression, American skyscrapers were either historical pastiches or tips of the hat to European art deco. Most famous were New York's Chrysler, Empire State, and Rockefeller Center buildings (of 1930 and 1931), featuring diagonal or zigzag "jazz age" ornament and equal amounts of glass and masonry in alternating vertical or horizontal strips forming crisp, rectilinear facades that nonetheless hide the frame. Two exceptions were noteworthy: Hood's 1929–1931 McGraw-Hill Building, designed with André Fouilhoux, in New York; and William Lescaze's 1929–1932 Philadelphia Savings Fund Society Building, designed with George Howe. Both were in what was labeled "the international style," which made structurally determined form something of a fetish.
It was fitting that the European émigrés Fouilhoux (from Paris) and Lescaze (from Zurich) figured prominently in the reconfiguration of American skyscrapers, because a third European, Mies van der Rohe, who arrived in Chicago in 1938, almost single-handedly completed the process, beginning with his 1946–1949 Promontory Apartments. More than any other edifice, his 1954–1958 Seagram Building in New York made the flatroofed, glass-walled, steel-or concrete-framed, minimally ornamented box a corporate signature as well as an indication that derivations of European modernism had captured the mainstream of American architecture.
A comparison of the two McGraw-Hill Buildings in New York suggests how much had changed since 1929. The first, by Hood with Fouilhoux, is bluish-green glazed terra-cotta and steps back five times before reaching its penthouse, which is sided with huge firm-name graphics. Its thirty-five richly textured, horizontally articulated stories complement the vertical thrust of the elevator shafts and stairwell. Although resolutely international in style, it resembles no other building. The four identical facades of the second McGraw-Hill Building, built in 1973 by Harrison, Abramovitz, and Harris, soar without interruption or variation through forty-five stories of closely spaced reddish granite columns. Devoid of graphics, it is a clone of the flanking Celanese and Exxon Buildings by the same architects. In less than half a century, collective anonymity replaced architectural individuality in every American city.
The low profile adopted by American corporations after World War II gave way in the 1980s to a more assertive public posture expressed architecturally in post-modernism (POMO): the return of polychrome, ornament, and historical reference enlivened by mixtures of nonorthogonal with rectilinear geometries. Rejecting the Mies-inspired modernist box and companion frame-based aesthetic, POMO recaptured a spirit of experimentation akin to that of the European 1920s but enhanced by an array of new materials and technologies, including computer-assisted design. The sky was again the limit in terms not of height but of artistic possibility.
Globalization of capital internationalized the profession. For example, four architects were invited in 2000 to submit proposals for a new New York Times headquarters: Norman Foster of London; Renzo Piano with offices in Paris and Genoa; Cesar Pelli, the Argentina-born dean of the Yale School of Art and Architecture; and Frank Gehry, a Toronto native residing in California. Gehry produced a twisting, undulating, concave and convex agglomeration of sinewy, computer-generated, non-Euclidean shapes that appears to be one tower or three, depending on the viewer's vantage point. Like the other submissions, it makes no reference except for signage to site or function, suggesting that any one of the four could be erected anywhere to serve any purpose. Sharing only the absence of similarity, they are as far removed from the modernist box as that was from the Woolworth Building.
During the course of a century, an American commercial building type, stylistically conditioned by historical precedent or by the steel frame, became an omnifunctional symbol of globalization conditioned only by architectural imagination. Technical limits to skyscraper height may be approaching, but form has no limits at all.
Goldberger, Paul. The Skyscraper. New York: Knopf, 1981.
Scuri, Piera. Late-Twentieth-Century Skyscrapers. New York: Van Nostrand Reinhold, 1990.
Twombly, Robert. Power and Style: A Critique of Twentieth-Century Architecture in the United States. New York: Hill and Wang, 1995.
Van Leeuwen, Thomas A. P. The Skyward Trend of Thought: The Metaphysics of the American Skyscraper. Cambridge, Mass.: MIT Press, 1988.
"Skyscrapers." Dictionary of American History. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/skyscrapers
"Skyscrapers." Dictionary of American History. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/skyscrapers
skyscraper, modern building of great height, constructed on a steel skeleton. The form originated in the United States.
Development of the Form
Many mechanical and structural developments in the last quarter of the 19th cent. contributed to its evolution. With the perfection of the high-speed elevator after 1887, skyscrapers were able to attain any desired height. The earliest tall buildings were of solid masonry construction, with the thick walls of the lower stories usurping a disproportionate amount of floor space. In order to permit thinner walls through the entire height of the building, architects began to use cast iron in conjunction with masonry. This was followed by cage construction, in which the iron frame supported the floors and the masonry walls bore their own weight.
The next step was the invention of a system in which the metal framework would support not only the floors but also the walls. This innovation appeared in the Home Insurance Building in Chicago, designed in 1883 by William Le Baron Jenney—the first building to employ steel skeleton construction and embody the general characteristics of a modern skyscraper. The subsequent erection in Chicago of a number of similar buildings made it the center of the early skyscraper architecture. In the 1890s the steel frame was formed into a completely riveted skeleton bearing all the structural loads, with the exterior or thin curtain walls serving merely as an enclosing screen.
Legal and Aesthetic Refinements
In 1892 the New York Building Law made its first provisions for skeleton constructions. There followed a period of experimentation to devise efficient floor plans and aesthetically satisfying forms. In New York City the Flatiron Building by D. H. Burnham was constructed in 1902, the Metropolitan Life Insurance Tower in 1909, and the Woolworth Building, 60 stories high, by Cass Gilbert, in 1913. The last, with Gothic ornamentation, exemplifies the general tendency at that time to adapt earlier architectural styles to modern construction. The radical innovator Louis Henry Sullivan gave impetus to a new, bold aesthetic for skyscrapers. An excellent example is his design for the Wainwright building in St. Louis (1890–91). Frank Lloyd Wright also contributed his unorthodox vision to such structures as the Price Tower (1953) in Bartlesville, Okla.
In 1916, New York City adopted the Building Zone Resolution, establishing legal control over the height and plan of buildings and over the factors relating to health, fire hazard, and assurance of adequate light and air to buildings and streets. Regulations regarding the setting back of exterior walls above a determined height, largely intended to allow light to reach the streets, gave rise to buildings whose stepped profiles characterize the American skyscraper of subsequent years.
With the complex structural and planning problems solved, architects still seek solutions to the difficulties of integrating skyscrapers with community requirements of hygiene, transportation, and commercial interest. In New York during the 1950s, public plazas were incorporated into the designs of the Lever House by Gordon Bunshaft and the Seagram Building of Mies van der Rohe. These International style buildings are also examples of the effective use of vast expanses of glass in skyscrapers. More recently, numerous skyscrapers have been constructed in a number of postmodern modes.
By convention, a skyscraper is a building that is used primarily for human habitation with the greatest majority of its height divided into occupiable floors. Freestanding structures used primarily for broadcasting or sightseeing are classified as towers. The height of a building is measured from the sidewalk level of the main entrance to the structural top of the building. This includes spires but does not include television antennas, radio antennas, or flagpoles. By this definition the tallest building is the Burj Khalifa, Dubai, United Arab Emirates, which was topped off in 2009 at 2,717 ft (828 m) and 160 stories; it is also tallest structure in the world. Taipei 101, Taipei, Taiwan, is the second tallest at 1,671 ft (509 m) and 101 stories in 2003. The twin Petronas Towers (opened 1997) in Kuala Lumpur, Malaysia, are the third tallest; 88 stories high and topped by twin spires, they stand 1,483 ft (456 m) tall. The Willis Tower (opened 1974, formerly the Sears Tower) in Chicago is the tallest building in the United States; its 110 stories rise 1,454 ft (443 m) with an additional 253 ft (77 m) for the television antenna on top.
Among the highest New York City skyscrapers are One World Trade Center, the primary building in the new World Trade Center complex, with 104 stories, 1,776 ft (541 m) high; 432 Park Ave., with 96 stories, 1,396 ft (424 m) high; the Empire State Building, with 102 stories, 1,250 ft (381 m) high; the Chrysler Building, with 77 stories, 1,048 ft (319 m) high; 60 Wall Tower, with 67 stories, 950 ft (290 m) high; and the GE (formerly RCA) Building in Rockefeller Center, with 70 stories, 850 ft (259 m) high. The former World Trade Center, which was the tallest building in the city until it was destroyed (Sept., 2001) by a terrorist attack, had two unstepped, rectangular towers of 110 stories each, one 1,362 ft (415 m) and the other 1,368 ft (417 m) high.
See K. Sabbagh, Skyscraper: The Making of a Building (repr. 1991); C. Willis, Form Follows Finance: Skyscrapers and Skylines in New York and Chicago (1995); P. Johnson and J. Dupre, Skyscrapers (1996); D. Hoffmann, Frank Lloyd Wright, Louis Sullivan, and the Skyscraper (1999); S. B. Landau and C. W. Condit, The Rise of the New York Skyscraper, 1865–1913 (repr. 1999).
"skyscraper." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/skyscraper
"skyscraper." The Columbia Encyclopedia, 6th ed.. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/skyscraper
Bletter & and Robinson (1975);
Condit (1952, 1960, 1961, 1964, 1968, 1973);
H H Sturgis (1985);
D. Hoffmann (1988);
S. Landau & and Condit (1996);
C. Willis (1995);
Zukowsky (ed.) (1987)
"skyscraper." A Dictionary of Architecture and Landscape Architecture. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/skyscraper
"skyscraper." A Dictionary of Architecture and Landscape Architecture. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/skyscraper
"skyscraper." World Encyclopedia. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/skyscraper
"skyscraper." World Encyclopedia. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/skyscraper
sky·scrap·er / ˈskīˌskrāpər/ • n. 1. a very tall building of many stories. 2. another term for skysail.
"skyscraper." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/skyscraper-0
"skyscraper." The Oxford Pocket Dictionary of Current English. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/skyscraper-0
"skyscraper." Oxford Dictionary of Rhymes. . Encyclopedia.com. (May 22, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/skyscraper
"skyscraper." Oxford Dictionary of Rhymes. . Retrieved May 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/skyscraper