1、Literature translation. Construction constituent Materials and structural forms are combined to make up the various parts of a building, including the load-carrying frame, skin, floors, and partitions. The building also has mechanical and electrical systems, such as elevators, heating and cooling sy
2、stems, and lighting systems. The superstructure is that part of a building above ground, and the substructure and foundation is that part of a building below ground. The skyscraper owes its existence to two developments of the 19th century: steel skeleton construction and the passenger elevator. Ste
3、el as a construction material dates from the introduction of the Bessemer converter in 1885.Gustave Eiffel (1832-1932) introduced steel construction in France. His designs for the Galerie des Machines and the Tower for the Paris Exposition of 1889 expressed the lightness of the steel framework. The
4、Eiffel Tower, 984 feet (300 meters) high, was the tallest structure built by man and was not surpassed until 40 years later by a series of American skyscrapers. Elisha Otis installed the first elevator in a department store in New York in 1857.In 1889, Eiffel installed the first elevators on a grand
5、 scale in the Eiffel Tower, whose hydraulic elevators could transport 2,350 passengers to the summit every hour. Load-Carrying Frame Until the late 19th century, the exterior walls of a building were used as bearing walls to support the floors. This construction is essentially a post and lintel type
6、, and it is still used in frame construction for houses. Bearing-wall construction limited the height of building because of the enormous wall thickness required； for instance, the 16-story Monadnock Building built in the 1880s in Chicago had walls 5 feet (1.5 meters) thick at the lower floors. In 1
7、883, William Le Baron Jenney (1832-1907) supported floors on cast-iron columns to form a cage-like construction. Skeleton construction, consisting of steel beams and columns, was first used in 1889. As a consequence of skeleton construction, the enclosing walls become a “curtain wall” rather than se
8、rving a supporting function. Masonry was the curtain wall material until the 1930s, when light metal and glass curtain walls were used. After the introduction of buildings continued to increase rapidly. All tall buildings were built with a skeleton of steel until World War . After the war, the short
9、age of steel and the improved quality of concrete led to tall building being built of reinforced concrete. Marina Tower (1962) in Chicago is the tallest concrete building in the United States； its height588 feet (179 meters)is exceeded by the 650-foot (198-meter) Post Office Tower in London and by o
10、ther towers. A change in attitude about skyscraper construction has brought a return to the use of the bearing wall. In New York City, the Columbia Broadcasting System Building, designed by Eero Saarinen in 1962,has a perimeter wall consisting of 5-foot (1.5meter) wide concrete columns spaced 10 fee
11、t (3 meters) from column center to center. This perimeter wall, in effect, constitutes a bearing wall. One reason for this trend is that stiffness against the action of wind can be economically obtained by using the walls of the building as a tube； the World Trade Center building is another example
12、of this tube approach. In contrast, rigid frames or vertical trusses are usually provided to give lateral stability. Floors The construction of the floors in a building depends on the basic structural frame that is used. In steel skeleton construction, floors are either slabs of concrete resting on
13、steel beams or a deck consisting of corrugated steel with a concrete topping. In concrete construction, the floors are either slabs of concrete on concrete beams or a series of closely spaced concrete beams (ribs) in two directions topped with a thin concrete slab, giving the appearance of a waffle
14、on its underside. The kind of floor that is used depends on the span between supporting columns or walls and the function of the space. In an apartment building, for instance, where walls and columns are spaced at 12 to 18 feet (3.7 to 5.5 meters), the most popular construction is a solid concrete s
15、lab with no beams. The underside of the slab serves as the ceiling for the space below it. Corrugated steel decks are often used in office buildings because the corrugations, when enclosed by another sheet of metal, form ducts for telephone and electrical lines. Soils and Foundations All building ar
16、e supported on the ground, and therefore the nature of the soil becomes an extremely important consideration in the design of any building. The design of a foundation depends on many soil factors, such as type of soil, soil stratification, thickness of soil lavers and their compaction, and groundwat
17、er conditions. Soils rarely have a single composition； they generally are mixtures in layers of varying thickness. For evaluation, soils are graded according to particle size, which increases from silt to clay to sand to gravel to rock. In general, the larger particle soils will support heavier load
18、s than the smaller ones. The hardest rock can support loads up to 100 tons per square foot(976.5 metric tons/sq meter), but the softest silt can support a load of only 0.25 ton per square foot(2.44 metric tons/sq meter). All soils beneath the surface are in a state of compaction； that is, they are u
19、nder a pressure that is equal to the weight of the soil column above it. Many soils (except for most sands and gavels) exhibit elastic propertiesthey deform when compressed under load and rebound when the load is removed. The elasticity of soils is often time-dependent, that is, deformations of the
20、soil occur over a length of time which may vary from minutes to years after a load is imposed. Over a period of time, a building may settle if it imposes a load on the soil greater than the natural compaction weight of the soil. Conversely, a building may heave if it imposes loads on the soil smalle
21、r than the natural compaction weight. The soil may also flow under the weight of a building； that is, it tends to be squeezed out. Due to both the compaction and flow effects, buildings tend settle. Uneven settlements, exemplified by the leaning towers in Pisa and Bologna, can have damaging effectst
22、he building may lean, walls and partitions may crack, windows and doors may become inoperative, and, in the extreme, a building may collapse. Uniform settlements are not so serious, although extreme conditions, such as those in Mexico City, can have serious consequences. Over the past 100 years, a change in the groundwater level there has caused some buildings to settle more than 10 feet (3 meters). Because such movements can occur during and after construction, careful analysis of the behavior of soils under a building is
