You do know what an architect does don't you? Certainly NOT if you think they design skyscrapers ...
They design the esthetics of a room or building ... NOT the actual structure - that's for the civil engineers to do!!!!
Skyscraper design and construction
From Wikipedia, the free encyclopedia
A workman on the framework of the Empire State Building
The design and construction of skyscrapers involves creating safe, habitable spaces in very high buildings. The buildings must support their weight, resist wind and earthquakes, and protect occupants from fire. Yet they must also be conveniently accessible, even on the upper floors, and provide utilities and a comfortable climate for the occupants. The problems posed in skyscraper design are considered among the most complex encountered given the balances required between economics, engineering, and construction management.
1 Basic design considerations
2 Loading and vibration
2.1 Shear walls
2.2 Steel frame
2.3 Tube frame
3 The elevator conundrum
4 See also
6 Further reading
7 External links
Basic design considerations
Good structural design is important in most building designs, but particularly for skyscrapers since even a small chance of catastrophic failure is unacceptable given the high prices of construction. This presents a paradox to civil engineers: the only way to assure a lack of failure is to test for all modes of failure, in both the laboratory and the real world. But the only way to know of all modes of failure is to learn from previous failures. Thus, no engineer can be absolutely sure that a given structure will resist all loadings that could cause failure, but can only have large enough margins of safety such that a failure is acceptably unlikely. When buildings do fail, engineers question whether the failure was due to some lack of foresight or due to some unknowable factor.
Loading and vibration
Taipei 101 endures a typhoon (2005)
The load a skyscraper experiences is largely from the force of the building material itself. In most building designs, the weight of the structure is much larger than the weight of the material that it will support beyond its own weight. In technical terms, the dead load, the load of the structure, is larger than the live load, the weight of things in the structure (people, furniture, vehicles, etc.). As such, the amount of structural material required within the lower levels of a skyscraper will be much larger than the material required within higher levels. This is not always visually apparent. The Empire State Building's setbacks are actually a result of the building code at the time, and were not structurally required. On the other hand, John Hancock Center's shape is uniquely the result of how it supports loads. Vertical supports can come in several types, among which the most common for skyscrapers can be categorized as steel frames, concrete cores, tube within tube design, and shear walls.
The wind loading on a skyscraper should also be considered. In fact, the lateral wind load imposed on super-tall structures is generally the governing factor in the structural design. Wind pressure increases with height, so for very tall buildings, the loads associated with wind are larger than dead or live loads.
Other vertical and horizontal loading factors come from varied, unpredictable sources, such as earthquakes.
OR maybe if I put it in language that my father (also a Civil Engineer, and who worked with the firm that built the CN Tower) taught me regarding architects ... They don't know shyte about buildings except how to make them look pretty
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,
An example of a skyscraper ground floor design and 6uilding frame.
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.
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