Skyscrapers

The name "skyscrapers" is a coined word for a modern
building of great height, constructed on a steel skeleton.
It originated in the United States and many mechanical and
structural development sin the last quarter of the 19th
century contributed to its evolution. With the perfecting
of high-speed electric elevators, skyscrapers were free to
attain any desired heights. 

The earliest tall buildings were of solid masonry
construction with the thick walls of the lower stories
requiring an enormous amount of floor space. As greater
heights were planned, the need arose for a form of
construction that would permit thinner walls through the
entire height of the building. Architects began to use cast
iron with masonry, and this was followed by cage
construction, in which the iron frame supported the floors
and the masonry walls bore their own weight. 

The next step was invention of a system in which the metal
framework would support not only the floors but also the
walls. This was designed by William Le Baron Jenny in 1883,
in the Home Insurance Building in Chicago. It was the first
building in the world that employed steel skeleton
construction and resembled a modern skyscraper. A number of
other similar constructions followed, making Chicago the
birthplace of the early skyscrapers. 

In the 1890's, the steel frame was developed into its final
form, that of a completely riveted skeleton bearing all the
structural loads, with the exterior or thin curtain walls
serving merely as an enclosing screen. There followed a
period of numerous experiments in in devising efficient
floor plans and in seeking a satisfying architectural form. 

In 1916, New York city adopted the Building Zone
Resolution, establishing legal control over the height and
plan of buildings and over the factors relating to health,
fire hazard, and assurance of adequate light and air to
buildings and streets. Regulations regarding the setting
back of exterior walls above a determined height gave rise
to the setback buildings whose stepped profiles
characterize the contemporary American skyscraper.