高层建筑------英文翻译.doc

Introduction
It is difficult to define a high-rise building . One may say that a low-rise building ranges from 1 to 2 stories . A medium-rise building probably ranges between 3 or 4 stories up to 10 or 20 stories or more .
Although the basic principles of vertical and horizontal subsystem design remain the same for low- , medium- , or high-rise buildings , when a building gets high the vertical subsystems become a controlling problem for two reasons . Higher vertical loads will require larger columns , walls , and shafts . But , more significantly , the overturning moment and the shear deflections produced by lateral forces are much larger and must be carefully provided for .
The vertical subsystems in a high-rise building transmit accumulated gravity load from story to story , thus requiring larger column or wall sections to support such loading . In addition these same vertical subsystems must transmit lateral loads , such as wind or seismic loads , to the foundations. However , in contrast to vertical load , lateral load effects on buildings are not linear and increase rapidly with increase in height . For example under wind load , the overturning moment at the base of buildings varies approximately as the square of a buildings may vary as the fourth power of buildings height , other things being equal. Earthquake produces an even more pronounced effect.


前 沿
高层建筑的定义很难确定。可以说2-3层的建筑物为底层建筑，而从3-4层地10层或20层的建筑物为中层建筑，高层建筑至少为10层或者更多。
尽管在原理上，高层建筑的竖向和水平构件的设计同低层及多层建筑的设计没什么区别，但使竖向构件的设计成为高层设计有两个控制性的因素：首先，高层建筑需要较大的柱体、墙体和井筒；更重要的是侧向里所产生的倾覆力矩和剪力变形要大的多，必要谨慎设计来保证。
高层建筑的竖向构件从上到下逐层对累积的重力和荷载进行传递，这就要有较大尺寸的墙体或者柱体来进行承载。同时，这些构件还要将风荷载及地震荷载等侧向荷载传给基础。但是，侧向荷载的分布不同于竖向荷载，它们是非线性的，并且沿着建筑物高度的增加而迅速地增加。例如，在其他条件都相同时，风荷载在建筑物底部引起的倾覆力矩随建筑物高度近似地成平方规律变化，而在顶部的侧向位移与其高度的四次方成正比。地震荷载的效应更为明显。