Skyscraper is the name given to the world’s tallest buildings. These giant structures first appeared during the late 1800’s in Chicago and New York City. Skyscrapers provide space for offices, apartments, stores, hotels, restaurants, sports clubs, and other facilities. Some skyscrapers have so much space and serve so many functions that they resemble small cities.
Building skyscrapers.
Skyscrapers have two main parts, the foundation (the part below ground) and the superstructure (the part above ground). Both parts help support the load (weight or force) of the building. In skyscrapers over 40 stories tall, the wind load—that is, the force of the wind blowing against the sides of the building—becomes more important than the weight. The superstructure transmits the load to the foundation. The foundation consists of steel or concrete columns called piles that rest on a layer of solid rock or soil. The foundation transmits the load to this supporting layer.
In most buildings less than four stories high, the walls transmit the load to the foundation, but skyscrapers require a different type of construction. In skyscrapers, a steel or concrete frame supports the building much as a skeleton supports a body. The walls transmit no load but merely hang on the frame like curtains. The beams, girders, and columns that make up this skeleton carry the loads of the roof, walls, and floors.
Building a skyscraper requires careful planning. First, the construction crew digs a hole one or more stories deep for the foundation. During this process, factory-made pieces of the frame, such as steel beams and columns, are delivered to the site. After completing the foundation, the crew uses cranes to raise the pieces of the frame and then bolts them together.
As the frame goes up, other workers lay the floors and put on the outside walls. They finish the lower stories before completing the top of the skyscraper, but they must complete the entire building before installing elevators and other systems. A construction firm can put up a skyscraper frame in a few weeks, but it may take several years to finish the building.
Service areas.
A skyscraper’s interior contains rentable space and service areas. Service areas include corridors, stairs, lobbies, elevators, and machine rooms. These areas provide such internal systems as plumbing, air conditioning, electrical systems, and elevators.
Plumbing systems
consist of a water supply system and a drainage system. The water supply system brings clean water to plumbing fixtures. In a skyscraper, pumps increase the pressure within the pipes so that water reaches the upper floors of the building. The drainage system carries away water and waste materials.
Air conditioning systems
control the temperature within skyscrapers. Most air conditioners used in large buildings heat air by blowing it over coils filled with hot water or steam. A boiler heated by a gas or oil burner produces the hot water or steam. In some air conditioners, electric heaters warm the air. To cool the air, most air conditioners blow the air over coils filled with cold water or a chemical refrigerant.
The air conditioning system then circulates the warmed or cooled air throughout the skyscraper. Fans blow conditioned air into a room through ducts. Other fans return used air and blow some of it out of the building. The system returns the remaining used air to the air conditioner and mixes it with air from outside.
Electrical systems
provide power and communication systems. In many skyscrapers, power from the local utility company enters at the base of the building. Wires carry the electric current to each floor and supply power for lighting, office equipment, and other purposes. Electrical systems also provide skyscrapers with communication systems, including telephones and computers. In some skyscrapers, builders mount a second floor on top of the structural floor to create a space for the wiring needed for telephone, computer, and power systems. In others, ducts within the structural floor enclose wiring.
Elevators
in skyscrapers travel at speeds as high as 2,000 feet (600 meters) per minute. A group of elevators typically serves a zone of 15 to 20 floors (see Elevator ).
History.
The many parts and systems of a modern skyscraper did not all appear at once. The skyscraper developed in stages during the second half of the 1800’s. At that time, builders began to use safety elevators, metal frames, and other new technologies that made the modern skyscraper possible. Before elevators, for example, the height of buildings was limited by the number of stairs people were willing or able to climb. 
Skyscrapers first emerged in Chicago and New York City. In these cities, business people wanted concentrated centers that would provide quick access to offices, warehouses, and banks. Rising land costs also increased the desire to build upward. The Home Insurance Building (1884-1885) in Chicago, designed by William Le Baron Jenney, was a well-known “ancestor” of the skyscraper. This 10-story building, which was demolished in 1931, had a metal frame that supported much of its load.
