【文章內(nèi)容簡介】 內(nèi)部液體壓力，從而達到水密性。此后，預(yù)應(yīng)力開發(fā)步伐的加快在美國的坦克和管道，水，液體的數(shù)千輛坦克，儲氣庫的建成和預(yù)應(yīng)力壓力管道鋪設(shè)在隨后的二，三十年的里程。 線性預(yù)應(yīng)力繼續(xù)在歐洲和法國發(fā)展，特別是通過別出心裁的尤金的Freyssinet，提出在1923年至1928年的方法，他介紹了現(xiàn)在眾所周知和公認的Freyssinet系統(tǒng)。 。五米哈伊洛夫，俄羅斯，德國，樓倫哈德和TY美國林也作出了很大貢獻預(yù)應(yīng)力混凝土設(shè)計的藝術(shù)和科學(xué)。林的負載均衡方法值得特別提及的是，在這方面，因為它大大簡化，特別是在連續(xù)結(jié)構(gòu)設(shè)計過程中。這些20世紀的發(fā)展，導(dǎo)致在世界各地，特別是美國和預(yù)應(yīng)力的廣泛使用。通常情況下，大幅度提高抗壓強度混凝土用于預(yù)應(yīng)力結(jié)構(gòu)比普通鋼筋混凝土建造的。這有幾個原因：（1）高強度混凝土通常有較高的彈性模量。這意味著應(yīng)用預(yù)應(yīng)力下的初始彈性應(yīng)變的降低和減少蠕變，這大約是成正比的彈性應(yīng)變。預(yù)應(yīng)力損失減少的結(jié)果。（2）在后張法施工，高承載強調(diào)在預(yù)應(yīng)力筋轉(zhuǎn)移到直接承擔(dān)對混凝土的錨固件，其中梁的最終結(jié)果。這個問題可以通過增加錨固件的大小或增加混凝土的承載能力，提高其抗壓強度符合。后者通常是更經(jīng)濟。 今日建筑用預(yù)應(yīng)力混凝土地下結(jié)構(gòu)，電視發(fā)射塔，浮式儲油和海上建筑物，電站，核反應(yīng)堆容器，橋梁系統(tǒng)的種類繁多，包括段和斜拉索橋。他們表現(xiàn)出預(yù)應(yīng)力概念及其包羅萬象的應(yīng)用程序的通用性。在所有這些結(jié)構(gòu)的發(fā)展和建設(shè)的成功，是由于在材料技術(shù)的進步不小的措施，特別是預(yù)應(yīng)力鋼，積累的知識，在估算預(yù)應(yīng)力部隊的短期和長期虧損。附件1：外文資料翻譯原文building types and designA building is closely bound up with people，for it provides with the necessary space to work and live in . As classified by their use ,buildings are mainly of two types :industrial buildings and civil buildings .industrial buildings are used by various factories or industrial production while civil buildings are those that are used by people for dwelling ,employment ,education and other social activities . Industrial buildings are factory buildings that are available for processing and manufacturing of various kinds ,in such fields as the mining industry ,the metallurgical industry ,machine building ,the chemical industry and the textile industry . factory buildings can be classified into two types singlestory ones and multistory ones .the construction of industrial buildings is the same as that of civil buildings .however ,industrial and civil buildings differ in the materials used and in the way they are used . Civil buildings are divided into two broad categories: residential buildings and public buildings .residential buildings should suit family life .each flat should consist of at least three necessary rooms : a living room ,a kitchen and a toilet .public buildings can be used in politics ,cultural activities ,administration work and other services ,such as schools, office buildings, parks ,hospitals ,shops ,stations ,theatres ,gymnasiums ,hotels ,exhibition halls ,bath pools ,and so on .all of them have different functions ,which in turn require different design types as well. Housing is the living quarters for human beings .the basic function of housing is to provide shelter from the elements ,but people today require much more that of their housing .a family moving into a new neighborhood will to know if the available housing meets its standards of safety ,health ,and fort .a family will also ask how near the housing is to grain shops ,food markets ,schools ,stores ,the library ,a movie theater ,and the munity center . In the mid1960’s a most important value in housing was sufficient space both inside and out .a majority of families preferred singlefamily homes on about half an acre of land ,which would provide space for sparetime activities .in highly industrialized countries ,many families preferred to live as far out as possible from the center of a metropolitan area ,even if the wage earners had to travel some distance to their work .quite a large number of families preferred country housing to suburban housing because their chief aim was to get far away from noise ,crowding ,and confusion .the accessibility of public transportation had ceased to be a decisive factor in housing because most workers drove their cars to work .people we’re chiefly interested in the arrangement and size of rooms and the number of bedrooms . Before any of the building can begin ,plans have to be drawn to show what the building will be like ,the exact place in which it is to go and how everything is to be done. An important point in building design is the layout of rooms ,which should provide the greatest possible convenience in relation to the purposes for which they are intended .in a dwelling house ,the layout may be considered under three categories : “day”, “night” ,and “services” .attention must be paid to the provision of easy munication between these areas .the “day “rooms generally include a diningroom ,sittingroom and kitchen ,but other rooms ,such as a study ,may be added ,and there may be a hall .the livingroom ,which is generally the largest ,often serves as a diningroom ,too ,or the kitchen may have a dining alcove .the “night “rooms consist of the bedrooms .the “services “prise the kitchen ,bathrooms ,larder ,and waterclosets .the kitchen and larder connect the services with the day rooms . It is also essential to consider the question of outlook from the various rooms ,and those most in use should preferably face south as possible .it is ,however ,often very difficult to meet the optimum requirements ,both on account of the surroundings and the location of the roads .in resolving these plex problems ,it is also necessary to follow the local townplanning regulations which are concerned with public amenities ,density of population ,height of buildings ,proportion of green space to dwellings ,building lines ,the general appearance of new properties in relation to the neighbourhood ,and so on . There is little standardization in industrial buildings although such buildings still need to ply with local townplanning regulations .the modern trend is towards light ,airy factory buildings .generally of reinforced concrete or metal construction ,a factory can be given a “shed ”type ridge roof ,incorporating windows facing north so as to give evenly distributed natural lighting without sunglare .Assessment of natural radioactivity levels and radiation hazards due to cement industry AbstractThe cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentrations of 226Ra, 232Th and 40K in Assiut cement and other local cement types from different Egyptian factories has been measured by using γray spectrometry. From the measured γray spectra, specific activities were determined. Th