土木外文翻译----建筑结构的造价-建筑结构(编辑修改稿)

土木外文翻译----建筑结构的造价-建筑结构(编辑修改稿)内容摘要：

this suggests that creative integration of structural (and mechanical and electrical) design with the total architectural design concept can result in either a reduction in purely construction design concept can result in either a reduction in purely construction costs or more architecture for the same cost. Thus, the degree of success possible depends on knowledge, cleverness, and insightful collaboration of the designers and contractors. The above discussion is only meant to give the reader an overall perspective on total construction costs. The following sections will now furnish the means for estimating the cost of structure alone. Two alternative means will be provided for making an approximate structural cost estimate: one on a square foot of building basis, and another on volumes of structural materials used. Such costs can then be used to get a rough idea of total cost by referring to the “standards” for efficient design given above. At best, this will be a crude measure, but it is hoped that the reader will find that it makes hi m somewhat familiar with the type of real economic problems that responsible designers must deal with. At the least, this capability will be useful in paring alternative systems for the purpose of determining their relative cost efficiency. 3. Squarefoot Estimating As before, it is possible to empirically determine a “standard” persquarefoot cost factor based on the average of costs for similar construction at a given place and time. moreorless efficient designs are possible, depending on the ability of the designer and contractor to use materials and labor efficiently, and vary from the average. The range of squarefoot costs for “normal” structural systems is ﹩ 10 to ﹩ 16 psf. For example, typical office buildings average between ﹩ 12 and ﹩ 16 psf, and apartmenttype structures range from ﹩ 10 to ﹩ each case, the lower part of the range refers to short spans and low buildings, whereas the upper portion refers to longer spans and moderately tall buildings. Ordinary industrial structures are simple and normally produce squarefoot costs ranging from ﹩ 10 to ﹩ 14,as with the more typical apartment building. Although the spans for industrial structures are generally longer than those for apartment buildings, and the loads heavier, they monly have fewer plexities as well as fewer interior walls, partitions, ceiling requirements, and they are not tall. In other words, simplicity of design and erection can offset the additional cost for longer span lengths and heavier loads in industrial buildings. Of course there are exceptions to these averages. The limits of variation depend on a system’s plexity, span length over “normal” and special loading or foundation conditions. For example, the Crown Zellerbach highrise bank and office building in San Francisco is an exception, since its structural costs were unusually high. However, in this case, the use of 60 ft steel spans and freestanding columns at the bottom, which carry the considerable earthquake loading, as well as the special foundation associated with the poor San Francisco soil conditions, contributed to the exceptionally high costs. The design was also unusual for its time and a decision had been made to allow higher than normal costs for all aspects of the building to achieve open spaces and for both function and symbolic reasons. Hence the proportion of structural to total cost probably remained similar to ordinary buildings. The effect of spans longer than normal can be further illustrated. The “usual” floor span range is as follows: for apartment buildings,16 to 25 ft。 for office buildings,20 to 30 ft。 for industrial buildings,25 to 30 ft loaded heavily at 200 to 300 psf。 and garagetype structures span,50 to 60 ft, carrying relatively light(50～ 75 psf) loads(., similar to those for apartment and office structures).where these spans are doubled, the structural costs can be expected to rise about 20 to 30 percent. To increased loading in the case of industrial buildings offers another insight into the dependency of cost estimates on “usual” standards. If the loading in an industrial building were to be increased to 500psf(., two or three times), the additional structural cost would be on the order of another 20 to 30 percent. The reference in the above cases is for floor systems. For roofs using efficient orthotropic (flat) systems, contemporary limits for economical design appear to be on the order of 150 ft, whether of steel or prestressed concrete. Although space frames are often used for steel or prestressed concrete. Although spaceframes are often used for steel spans over 150 ft th。