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1、附录一、英文原文BuildingAbstract: There are a lot of building history and historical buildings, and the development of such as building materials and so on. Till now we have a better technology and science about building.Key words: modern buildings and structural materials, building types and design, compon
2、ents of a building.Modern Buildings and Structural MaterialsMany great buildings built in earlier ages are still in existence and in use. Among them are the Pantheon and Colosseum in Rome , Hagia Sophia in Istanbul; the Gothic churches of France and England, and the Renaissance cathedrals, with thei
3、r great domes, like the Duomo in Florence and St. Peters in Rome .They are massive structures with thick stone walls that counteract the thrust of the great weight. Thrust is the pressure exerted by each part of a structure on its other parts.These great buildings were not the products of knowledge
4、of mathematics and physics. They were constructed instead of the basis of experience and observation, often as the result of trial and error. One of the reasons they have survived is because of the great strength that was built into them-strength greater than necessary in most cases. But the enginee
5、rs of earlier times also had their failure. In Rome, for example, most of the people lived in insula, great tenement blocks that were often ten stories high. Many of them were poorly constructed and sometimes collapsed with considerable loss of life.Today, however, the engineer has the advantage not
6、 only of empirical information, but also of scientific data that permit him to make careful calculations in advance. When a modern engineer plans a structure, he takes into account the total weight of all its component materials. This is known as the dead load, which is the weight of the structure i
7、tself. He must also consider the live load, the weight of all the people, cars, furniture, machines, and so on that the structure will support when it is in use. In structures such as bridges that will handle fast automobile traffic, he must consider the impact, the force at which the live load will
8、 be exerted on the structure. He must also determine the safety factor, that is, an additional capability to make the structure stronger than the combination of the three other factors.The modern engineer must also understand the different stress to which the materials in a structure are subject. Th
9、ese include the opposite forces of compression and tension, In compression the material is pressed or pushed together; in tension the material is pulled apart or stretched, like a rubber band. In addition to tension and compression, another force is at work, namely shear, which we defined as the ten
10、dency of a material to fracture along the lines of stress. The shear might occur in a vertical plane, but it also might run along the horizontal axis of the beam, the neutral plane, where there is neither tension nor compression.Altogether, three forces can act on a structure: vertical-those that ac
11、t up or down; horizontal-those that act sideways; and those that act upon it with a rotating or turning motion. Forces that act at an angle are a combination of horizontal and vertical forces. Since the structures designed by civil engineers are intended to be stationary or stable, these forces must
12、 be kept in balance. The vertical forces, for example, must be equal to each other. If a beam supports a load above, the beam itself must have sufficient strength to counterbalance that weight. The horizontal forces must also equal each other so that there is not too much thrust either to the right
13、or to the left. And forces that might pull the structure around must be countered with forces that pull in the opposite direction.One of the most spectacular engineering failures of modern times, the collapse of the Tacoma Narrows Bridge in 1904, was the result of not considering the last of these f
14、actors carefully enough. When strong gusts of wind, up to six-five kilometers an hour, struck the bridge and also a lateral motion that caused the roadway to fall. Fortunately, engineers learn from mistakes, so it is now common practice to test scale models of bridges in wind runnels for aerodynamic
15、 resistance.The principal construction materials of earlier times were wood and masonry brick, stone, or tile, and similar materials. The Greeks and Romans sometimes used iron rods or clamps to strengthen their buildings. The columns of the Parthenon in Athens, for example, have holes drilled in the
16、m for iron bars that have now rusted away. The Romans also used a nature cement called pozzolana, made from volcanic ash, that become as hard as stone under water.Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. Steel, basically an alloy of iron and a small amount of carbon, had been made up to that time by a laborious process that restricted it to such special uses as sword blades
