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 columns are 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. The complete 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.

Workman on the frame of the Empire State Building
Image: Taken by Lewis Hine, edited by Durova,
Public domain, via Wikimedia Commons