What is a skeletal building structure?

A skeletal building structure is a steel frame that is built to support a large building or skyscraper. The structure consists of metal beams forming vertical columns crossed with steel girders for stability.

Skeletal building structures are formed by riveting together steel support beams and girders. For the largest and tallest buildings, diagonal girders are added for extra support. The places where the horizontal girders meet the vertical columns signal new floors. The entire skeleton is supported by a wide grid of girders on top of a concrete pad that forms the building's foundation. Insulation, walls, windows and interior components are added to complete the building.