外文翻譯tallbuildingstructure外文翻譯(文件)
【正文】 fficient. The advantage of this system is that the force exerted on a body by acceleration is simply the corresponding seismic coefficient multiplied by the weight of the body. This is in accordance with Equation (1) in which a/g is the seismic coefficient. Activity of faults All faults are not considered to present the same hazard. Some are classified as active since it is believed that these faults may undergo movement from time to time in the immediate geologic future. Unfortunately in the present stateoftheart there is a good deal of uncertainty in the identification of potentially active faults. For example, the fault that generated the San Fernando earthquake did not even appear on any published geological maps of the area. This fault was discovered to be active only when it actually slipped and ruptured the ground surface. Accordingly the identification of active faults and geologically hazardous areas for land use criteria and for hazard reduction by special engineering may be of questionable value. Only in very recent years have geologists begun to try to evaluate the potential activity of faults that have no historical record of activity. By close inspection of a fault, visible in the side walls of a trench that cuts across the fault, it is sometimes possible to determine if it has been active in recent times. For example, if the trace of the fault extends through a recent alluvial material, then there must have been slippage since that material was deposited. However fault ruptures may be very difficult or impossible to see in imbedded material such as sand and gravel. Also of course the location of the fault must be known and it must reach the surface of the ground in order to inspect it by trenching. Evidence of the historical activity of a fault may sometimes be obtained by observing the faulting of geologically young deposits exposed in a trench. Such deposits are generally bedded and well consolidated so that fault rupture can easily be seen. The approximate time of formation of a fault rupture or scarp has in some cases been determined by radiocarbon analysis of pieces of wood found in the rupture or scarp. In addition to evidence of young fault activity obtained by trenching, there also may be topographic evidence of young faulting such as is obvious along the San Andreas fault. Vertical aerial photographs are one of the most important methods for finding topographic evidence of active faults. This evidence, which includes scarps, offset channels, depressions, and elongated ridges and valleys, is produced by fault activity. The age of these topographic features and therefore the time of the fault activity, can be estimated by the extent to which they are weathered and eroded. 二、外文譯文： 高層建筑結(jié)構(gòu) 高樓大廈已經(jīng)著迷，從人類文明的開始，其建設(shè)是國防和最初其后教會的目的。s crust, termed a fault. The earth on one side of the fault slides or slips horizontally and /or vertically with respect to the earth on the opposite side, and this generates a vibration that is transmitted outward in all directions. This vibration c
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