Skyscrapers are the world’s tallest buildings. They first appeared in New York and Chicago at the end of the 19th century. Skyscrapers are often like small cities. They offer space for offices, apartments, shops, hotels, restaurants and other services. Tens of thousands of people live and work there.

Building Skyscrapers

Skyscrapers have two parts: the foundation is the part below the ground and the superstructure is the part above the ground. Both sections hold the weight of the building.

A skyscraper needs careful planning before it can be built. First a big hole a few stories deep is dug into the earth. Sometimes this foundation reaches into solid rock. Then steel and concrete beams and columnsare placed into it. They carry the weight of the superstructure.

When the foundation is finished cranes are used to raise a steel frame up into the sky. The pieces of this frame are bolted together. As it moves upward other workers lay floors and hang in the outside walls. Thecomplete structure of the skyscraper must be finished before the inside systems can be installed.

A skyscraper must also be able to hold off strong winds. Modern buildings are able to swing a few metres in each direction, like a tree, without damaging the structure. Sometimes a steel core rises upwards from the inside of the building to give it better support.

Service areas

Corridors , staircases, elevators, heating systems, air conditioning and electrical systems belong to the most important inner elements of a skyscraper. Although the outside structure can be completed in a few weeks it may take years to finish the whole building.

Pumps bring clean water to all parts of the skyscraper, thedrainage system carries away water and waste materials.

Air conditioning and heating systems control the temperature in the building the whole year round. Electrical systems provide power and communication throughout the building and wires carry electricity to each floor. Elevators are the most important systems of a skyscraper. They carry people up and down at speeds of up to 500 metres per minute.