Skyscraper

a type of tall business buildings of recent development. The meaning of the name is self-evident. It was applied first to the tall buildings that have loomed up, one after another, against the sky line in New York City. The year 1869 marks the beginning of the movement. The motive for building skyscrapers is moneymaking. So far as material and labor go, the cost of a ten-story structure is less than the cost of two five-story buildings of the same floor dimensions, while the cost of the ground on which to build is one-half as great. If rooms on the twentieth floor of an office building can be made as safe, as accessible, and as attractive as similar quarters on a third floor; if they can be built for less money; and if they will command an equal, or better yet, a greater rental, owners will build tall buildings. The same statement holds good for stores, hotels, and flats.

The height of earlier buildings was determined by the height to which tenants and customers could be induced to climb. Poverty, and hired help might, indeed, be forced into attics; sometimes attics and upper floors were provided with hoists and were utilized for storerooms; but experience showed that hotel guests, lawyers, clients, shoppers, and homeseekers refused to climb more than four stairways. Five stories was the business limit, and this height could be made profitable only in congested districts. The five-story limit was removed by the introduction of passenger elevators. Once in an elevator the client cares little for an extra story or two. Business men preferred offices on the fifth floor of a building provided with elevator service to offices on a third floor that could be reached only by climbing. Passenger elevators were introduced in the Fifth Avenue Hotel and the Astor House early in the sixties. Competition led to the introduction of elevators in office buildings. The term "elevator building" acquired a decided rental value.

The increasing safety, speed, and comfort of the passenger elevator, together with progress in fireproof construction, led Henry B. Hyde, president of the Equitable Life Insurance Company, to contract for the erection of a seven-story office building on Broadway. This was considered a rash step. The wise shook their heads and prophesied that the upper floors would stand vacant. Mr. Hyde came back by asking double rental for his sixth and seventh floors, and he got it. When tenants found that upper offices were cleaner, airier, lighter, cooler, and quite as accessible, they were ready to pay higher rentals. The Tribune followed with a nine-story building, the Western Union with a ten-story building, and the race was on. Other examples of these early, heavy-walled skyscrapers are the Ames in Boston and the Monadnock in Chicago, the latter rising to sixteen stories.

In the meantime, architects were studying ways and means of lightening the load which the walls must carry. To this end, and to save space as well, interior walls and piers of masonry were superseded by less bulky steel construction surrounded by hollow tiling. Fireproof construction and the introduction of passenger elevators removed the five-story limit; but for crowded districts, height was still limited by the difficulty of getting room for thick walls. The walls of masonry for a twenty-story building must be thicker than the walls of a five-story building. They need not be four times as massive; but it may be taken as a principle of architecture that the thickness of masonry material, and construction receiving the same, must increase as the height increases. If a proposed building be confined to a narrow lot, there must be a limit to the height of the masonry, lest the interior be reduced to a mere corridor. The escape from this dilemma is intensely interesting. The introduction of steel beams made by the inexpensive Bessemer process enabled architects to build entire interior partitions, floors, stairways, and all, quite independent of the outer wall. The interior became a huge, many-floored, steel-braced, steel cage, capable of standing alone and actually standing on its own part of the foundation. The wall, relieved of the floor burden, was reduced in thickness and became a mere outer wall designed for protection and supporting nothing but its own weight. This "cage" type of construction permitted lighter walls, but still the walls of a high building needed great thickness to support themselves--to prevent toppling.

The crowning step in the evolution of the skyscraper came in an inspiration to get on without the wall at all. As long as the whole interior was a rigid, independent frame, it remained only to devise some way of making it weather-proof; then the wall might go. The Crystal Palace erected in London in 1851, in the main an iron frame set with glass windows, may have given a hint. The skeleton frame of the palace, glass replaced by tiling, may have been a suggestion. The skeleton of the Eiffel Tower of Paris, with panels of tiling, may have suggested the thought, but, anyhow, the idea of "skeleton" construction was hit upon by Mr. Bradford L. Gilbert, the architect of the Tower Building of New York City. He found himself confronted with the problem of erecting a tall office building on a lot twenty-one feet six inches wide. Masonry walls carried to the height desired would have needed to be so thick as to leave scant room inside for elevators, to say nothing of offices to rent. He decided to build a steel frame as in cage construction, to cover the exterior as well as interior columns with tiling, and to fill in the spaces between the exterior beams and columns with tile panels. This was the first skyscraper without walls of masonry. As stated on a bronze tablet on the front of the Tower Building, 50 Broadway, New York, this was "the earliest example of the skeleton construction in which the entire weight of the walls and floors is borne and transmitted to the foundation by a framework of metallic posts and beams."

The modern skyscraper is not a structure of masonry. It is a steel frame building. This first steel building contained only eleven stories, but, by dispensing with walls of masonry, it again raised the limit to which the height of a building may be carried. Numerous skyscrapers of skeleton construction followed. The Times Building contains over twenty stories. The height of the new Singer Building, measured from sidewalk to top of construction, is 612 feet 1 inch; the height of the Metropolitan Building, from sidewalk to top of construction, is 700 feet 3 inches.

Architects claim there is no limit to the height of skeleton construction. Skyscrapers already contain forty stories, and fifty-story buildings are not considered a dream. In 1909 an announcement was made that the original eleven-story skeleton skyscraper, the Tower Building, standing on a lot little over twenty-one feet in width, was to be taken down and replaced by a building of thirty-eight stories.