Early skyscrapers
The earliest stage of skyscraper design encompasses buildings built between 1884 and 1945, predominantly in the American cities of New York and Chicago. Cities in the United States were traditionally made up of low-rise buildings, but significant economic growth after the American Civil War and increasingly intensive use of urban land encouraged the development of taller buildings beginning in the 1870s. Technological improvements enabled the construction of fireproofed iron-framed structures with deep foundations, equipped with new inventions such as the elevator and electric lighting. These made it both technically and commercially viable to build a new class of taller buildings, the first of which, Chicago's tall Home Insurance Building, opened in 1885. Their numbers grew rapidly, and by 1888 they were being labelled "skyscrapers".
Chicago initially led the way in skyscraper design, with many constructed in the center of its financial district during the late 1880s and early 1890s. Sometimes termed the products of the Chicago school of architecture, these skyscrapers attempted to balance aesthetic concerns with practical commercial design, producing large, square palazzo-styled buildings hosting shops and restaurants on the ground level and containing rentable offices on the upper floors. In contrast, New York's skyscrapers were frequently narrower towers which, more eclectic in style, were often criticized for their lack of elegance. In 1892, Chicago banned the construction of new skyscrapers taller than, leaving the development of taller buildings to New York.
A new wave of skyscraper construction emerged in the first decade of the 20th century. The demand for new office space to hold the expanding workforce of white-collar staff in the U.S. continued to grow. Engineering developments made it easier to build and live in yet taller buildings. Chicago built new skyscrapers in its existing style, while New York experimented further with tower design. Iconic buildings such as the Flatiron were followed by the tall Singer Tower, the Metropolitan Life Insurance Company Tower, and the Woolworth Building. Though these skyscrapers were commercial successes, criticism mounted as they broke up the ordered city skyline and plunged neighboring streets and buildings into perpetual shadow. Combined with an economic downturn, this led to the introduction of zoning restraints in New York in 1916.
In the interwar years, skyscrapers spread to nearly all major U.S. cities, while a total of around 100 were built in some other Western countries and Asian countries. The economic boom of the 1920s and extensive real estate speculation encouraged a wave of new skyscraper projects in New York and Chicago. New York City's 1916 Zoning Resolution helped shape the Art Deco or "set-back" style of skyscrapers, leading to structures that focused on volume and striking silhouettes, often richly decorated. Skyscraper heights continued to grow, with the Chrysler and the Empire State Buildings each claiming new records, reaching and respectively. With the onset of the Great Depression, the real estate market collapsed, and new builds stuttered to a halt, ending this era of skyscraper construction. Popular and academic culture embraced the skyscraper through films, photography, literature, and ballet, seeing the buildings as either positive symbols of modernity and science, or alternatively examples of the ills of modern life and society. Skyscraper projects after World War II typically rejected the designs of the early skyscrapers, instead embracing the international style; many older skyscrapers were redesigned to suit contemporary tastes or even demolished—such as the Singer Tower, once the world's tallest skyscraper.
Background: 1850–1879
Skyscraper precursors
Tall structures have been built in some form or another for millennia. Egypt's Great Pyramid of Giza, built in the 26th century BC at a height of, would remain the tallest structure on Earth for millennia until it was surpassed in the Middle Ages. The term "skyscraper" was first used in the 1780s to describe a particularly tall horse, before later being applied to, among other things, the sail at the top of a ship's mast, tall hats and bonnets, tall men, and a ball that was hit high into the air. In the 1880s it began to be applied to buildings, first in 1883 to describe large public monuments and then in 1889 as a label for tall office blocks, coming into widespread use over the next decade.Unlike the tall buildings of Antiquity and the Middle Ages, which were primarily built for ceremonial and religious purposes, skyscrapers were largely targeted towards business applications. Various [|technological developments] of the 19th century, which included such design elements as wind bracing and crucially the use of an iron-framed skeleton, further differentiated skyscrapers from earlier tall secular buildings, such as those in the Old Town of Edinburgh.
Development of these skyscrapers was concentrated in the American cities of New York and Chicago, but was not entirely exclusive to them; precursors of the form exist in Europe, especially the United Kingdom. The Ditherington Flax Mill was built in Shropshire in 1797 as the world's first iron-framed building, and as such has been referred to as "the father of the skyscraper".
Commercial and social drivers
Early skyscrapers emerged in the United States as a result of economic growth, the financial organization of American businesses, and the intensive use of land. New York City was one of the centers of early skyscraper construction and had a history as a key seaport located on the small island of Manhattan, on the east coast of the U.S. As a consequence of its colonial history and city planning, New York's real estate was broken up into many small parcels of land, with few large sites. During the first half of the 19th century it became the national center of American finance, and the banks in the financial district of Manhattan competed fiercely with English institutions for international dominance.The Great Fire of 1835 destroyed most of the old financial buildings, and in their place a wide variety of new buildings were erected and demolished in quick succession during the 1840s and 1850s; traveler Philip Hone suggested that the entire city was being rebuilt every decade. Most buildings adopted the Italian Renaissance inspired palazzo-style of architecture popular in England, and rose no more than five or six stories. New York did not have any restrictions on the height of buildings, but in practice low-rise buildings were the norm, at least until 1865, with the tallest buildings being the city's churches. New York's population tripled between 1840 and 1870, and property values soared, increasing by more than 90 percent between 1860 and 1875.
File:Downtown Chicago, 1874.jpg|thumb|left|Currier and Ives' 1874 map of Chicago shows low-rise buildings constructed after the fire of 1871|alt=A drawing of many square four- to five-story buildings, flatly covered
Further west, the city of Chicago became the other major site in the development of early skyscrapers. In contrast to New York, Chicago emerged as a major metropolis only in the mid-19th century, growing from a village of, and. Chicago became the railroad hub for the American West and the primary trading city for the emerging territories, famous for its commercial culture. It saw itself as different from the cities on the east coast and was immensely proud of its status as a growing, vibrant center. As early as 1868, its commercial buildings were touted as being "unequalled in the East for grandeur, business, or wealth", but such claims were regarded as risible.
By the 1870s, Chicago had become the main financial center for the West, but in October 1871 the Great Chicago Fire destroyed the majority of the wooden structures within the city. The city was rebuilt on large plots of land in a grid network and followed new city ordinances that prohibited construction in wood. These factors encouraged the building of taller properties in new innovative designs, which, like New York, saw a range of businesses and services being packed into single buildings. Especially popular in the post-fire era were "commercial blocks", several-story masonry buildings built to property lines with only one street facade that was adorned in such styles as Italianate, Classical Revival, and English Gothic. Such blocks, which were very flexible in their use, had already been prolific before the fire, and early post-fire reconstruction differed from the old styles downtown only in scale.
The construction of taller buildings during the 1870s was hindered by the financial Panic of 1873 and the ensuing economic depression, which lasted until around 1879. Construction slowed, and property values slumped. By 1880, however, the recovery was well underway, with new construction in New York returning to the pace of 1871, and the economic upturn making the construction of taller buildings an attractive financial option again, establishing many of the preconditions for the development of the skyscraper.
Technological developments
The emergence of skyscrapers was made possible by technological improvements during the middle of the 19th century. One of these developments was the iron framed building. Masonry buildings supported their internal floors through their walls, but the taller the building, the thicker the walls had to become, particularly at the base. In the 1860s, French engineers experimented with using built-up plate girders made of wrought iron to construct buildings supported by internal metal frames. These frames were stronger than traditional masonry and permitted much thinner walls. The methodology was extensively described in engineering journals and was initially used to build warehouses.Using these metal frames for taller buildings, however, meant exposing them to increased wind pressure. As a consequence, protective wind bracing had to be introduced, enabled by the work of Augustin-Jean Fresnel who produced equations for calculating the loads and moments on larger buildings. Metal-framed buildings were also vulnerable to fire and required special fireproofing. French engineers had made advances in this area in the early 19th century, and major breakthroughs came with the work of architect Peter Wight in the 1860s. Spurred on by the catastrophic fires in Chicago in 1871 and Boston in 1872, his findings were turned into a wide variety of patented fireproofing products during the 1870s.
Taller, heavier buildings such as skyscrapers also required stronger foundations than smaller buildings. Earlier buildings had typically rested their foundations on rubble, which was in turn laid down on the soft top layer of the ground called the overburden. As buildings became taller and heavier, the overburden could not support their weight, and foundations increasingly needed to rest directly on the bedrock below. In both New York and Chicago this required digging down a considerable distance through soft soil and often below the water table, risking the hole filling up with water before the foundations were complete. The deeper the foundations needed to be, the greater the challenge. Special water-tight boxes called caissons were invented to deal with this problem in England in 1830 and adopted in the U.S. during the 1850s and 1860s.
The development of the elevator was also essential to the emergence of the early skyscrapers, as office buildings taller than around six stories would have been impractical without them. Powered elevators were first installed in England during the 1830s and spread to U.S. factories and hotels by the 1840s. Elevators using hoist ropes, however, could only function effectively in low-rise buildings, and this limitation encouraged the introduction of the hydraulic elevator in 1870, even though early models contained dangerous design flaws. By 1876 these problems had been resolved, providing a solution for servicing the early skyscrapers.
New environmental technologies in heating, lighting, ventilation and sanitation were also critical to creating taller buildings that were attractive to work in. Central heating could not be easily extended to serve larger buildings; in the 1850s, a system using low-pressure steam and steam-operated fans became adopted in the construction of the later skyscrapers. Many U.S. buildings were lit by gas, but this carried safety risks and was difficult to install in taller buildings. As an alternative, electric lights were installed from 1878 onwards, powered by basement generators. Ventilation was also a challenge, as smoke drifting into offices from the streets and the fumes from the gas lighting made air quality a major health issue. A steam-driven, forced-draft ventilation system was invented in 1860 and became widely used in taller buildings by the 1870s, overcoming much of the problem. Improvements in iron piping permitted running hot and cold water and sanitation facilities to be installed throughout taller buildings for the first time.