土建学院土木工程专业外文翻译

1、外文文献翻译Reinforced ConcreteConcrete and reinforced concrete are used as building materials in everycountry.any, including the United Ses and Canada, reinforced concreteis a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the

2、wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete andreinforced concrete are used in bridges, build

3、ings of all sorts undergroundstructures, water,evitowers, offshore oil exploration andproduction structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed heir final location, or they may be precast concrete produced in a factory and erected at the

4、 construction site. Concrete structures may be severe and functional in design, or the shand layout and be whimsical and artistic.Few other building materials off the architect and engineer such versatilityand scope.Concrete is strong in compresbut weaken. As a result, cracksdevelop whenever loads,

5、or restrained shrinkage of temperature changes, giverise to tensile stresses in exs of the tensile strength of the concrete. Ina plain concrete beam, the moments about the neutral axis due to appd loadshe crack concreteare resisted by anernalprescouple involving tenconcrete. Such a beam fails very s

6、uddenly and compley when theforms. In a reinforced concrete beam, steel bars are embeddedhein such a wayt the tenforneeded for moment equilibrium after the he bars.concrete member involves building a fromconcrete cracks can be developedThe construction of a reinforcedof moldto support any forhe shof

7、 the member being built. The form must be strong enoughboth the weight and hydrosic prere of the wet concrete, andappd to it by workers, concrete buggies, wind, and so on. Thereinforcement is placedhis form and held in place during the concretingoperation. After the concrete has hardened, the forms

8、are removed. As the formsare removed, props of shores are installed to support the weight of the concreteuntil is reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength toresist the loads and adequate stiffness to prevent exsiv

9、e deflections. Inbeam must be proportioned sotit can be constructed. For example, thereinforcement must besince the concrete is placededsohet it can be assembledhe field, andform after the reinforcement is in place,the concrete must be able to flow around, betn, and past the reinforcementto fill all

10、 parts of the form compley.The choice of whether a structure should be built of concrete, steel, masonry,or timber depends on the availability of materials and on a number of valuedeci early1.s. The choice of structural system is made by the architect of engineer he design, based on the following co

11、nsiderations:Economy. Frequently, the foremost consideration is the overall const ofthe structure. This is, of course, a function of the costs of the materials andthe labor nesary to erect them. Frequently, however, the overall cost isaffected as much or more by the overall construction time since t

12、he contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commer l project, the cost ofconstruction financing will be a significant fraction

13、 of the total cost. As aresult, finanl savings due toraconstruction may moren offsetincreased material costs. For this to standardize the design and forcosts.reason, any measures the designer can takewill generally pay off in reduced overallany cases the long-term economy of the structure may be mor

14、e importantn theconsideration.cost. As a result, maenance and durability are important2. Suitability of material for architectural and structural function.Areinforced concrete system frequently allows the designer to combine thearchitectural and structural functions. Concrete has the placed in a pla

15、stic condition and is given the desired shof the forms and the finishing techniques. This allowadvantaget it isand texture by meansch elements ad flatplates or other types of slabs to serve as load-bearing elements while providingthe finished floor and / or ceiling surfa. Similarly, reinforced concr

16、etewalls can provide architecturally attractive surfain addition toing theability to resist gravity, wind, or seismic loads. Finally, the choice of sizeof shiserned by the designer and not by the availability of standard members. The structure in a building must withstand the effectsmanufactured3. F

17、ireof a fire and remain standing while the building is evacuated and the fire isextinguished. A concrete building inherently has a 1- to 3-hour fireratingtimberwithout spel fireproofing orothers. Structural steel orbuildings must be fireproofed toattain similar fire ratings.members inherently requir

18、e less ma4. Low maenance. Concreteenancen do structural steel or timber members. This is particularly true if dense,air-entrained concrete has been used for surfaexed to the atmosphere,and if care has been takenaway from the structure. Spehe design to provide adequate drainage ol precautions must be

19、 taken for concrete exndedto saltch as deicing chemicals.5. Availability of materials.Sand, gravel, cement, and concrete mixingfacilities are very widely available, and reinforcing steel can be transportedto most job sites more easilyn can structural steel. As a result, reinforcedconcrete is frequen

20、tly used in remote areas.On the other hand, there are a number octorst may cause one to selecta material othern reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lowernits compressive strength ( about 1/10 ), and hence concrete ibject to cracking.In str

21、uctural uses this ise by using reinforcement to carry tensileforand limit crack widths to within acceptable values. Unless care is takenin design and construction, however, these cracks may be unsightly or may allowpenetration of water. When this occurs, water or chemicalch as road deicingsalts may

22、cause deterioration or staining of the concrete. Spel designslare required in such cases.he case of water-retaining structures, spes and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-platructure involvesthree steps not encounteredhe constructio

23、n of steel or timber structures.These are ( a ) the construction of the forms, ( b ) the removal of these forms,and (c) propor shoring the new concrete to support its weight until itsstrength is adequate. Each of these steps involves labor and / or materials,which are not nesary with other forms of

24、construction.3. Relatively low strength per uni t of weight for volume.The compressivestrength of concrete is roughly 5 to 10%t of steel, while its unit densityis roughly 30%t of steel. As a result, a concrete structure requires a largervolume and a greater weight of materialn does a comparable stee

25、l structure.As a result, long-span structures are often built from steel.4.Time- dependentvolumechanges.Bothconcreteandsteelundergo-approximay the same amount of thermal expanand contraction.Because there is less mass of steel to be heated or cooled, and because steelis a better concrete, a steel st

26、ructure is generally affected by temperaturechanges to a greater extentn is a concrete structure. On the other hand,concrete undergoes frying shrinkage, which, if restrained, may cause deflectionsor cracking. Furthermore, deflections will tend to increase with time,doubling, due to creep of the conc

27、rete under sustained loads.siblyIn almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughouttheir profes al careers. Much of this te

28、xt is directly concerned with thebeior and proportioning of componentstmakeOnce willup typical reinforcedthe beior of these e the background toconcrete structures-beams, columns, and slabs.individual elements is understood, the designeryze and design a wide range of complex structures, such as found

29、ations,buildings, and bridges, comed of these elements.Since reinforced concrete is a no homogeneous materialt creeps, shrinks,and cracks, its stresses cannot be accuray predicted by the traditionalequations derived in a course in strength of materials for homogeneouselasticmaterials. Much of reinfo

30、rced concrete designherefore empirical, i.e.,design equations and design methods are based on experimental and time-provedresults instead of being derived exclusively from theoretical formulations.A thorougderstanding of the be the designer to convert an otherwisestructural elements and thereby take

31、ior of reinforced concrete will allowbrittle materialo tough ductileadvantage of concretes desirablecharacteristics, its high compressive strength, its firedurability., and itsConcrete, a stone like material, is made by mixing cement, water, fineaggregate ( often sand ), coarse aggregate, and freque

32、ntly other additives (te,modify properties )o a workable mixture. In its unhardened or plastic sconcrete can be placed in forms to produce a large variety of structural elements.Although the hardened concrete by itself, i.e., without any reinforcement, isstrong in compres, it lacks tensile strengnd

33、therefore cracks easily.Because unreinforced concrete is brittle, it cannot undergo large deformationsunder load and failddenly-without warning. The addition fo steelreinforcement to the concrete reduthe negative effects of its two principalinherent weaknesses, itsceptibility to cracking and its bri

34、ttleness. Whenthe reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforcedconcrete, is used extensively to construct foundations, structural frames,storage takes, sroofs, highways, walls, dams, cs, and innumera

35、ble otherstructures and building products. Two other characteristics of concretet are present even when concrete is reinforced are shrinkage and creep, but thenegative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standardst control impor

36、tants of design and construction. The pure of codes it produtructuressot the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originatedand controlled by spelists who are concerned with the proper use of a specificmater

37、ial or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to coverconstruction in a given region, often a city or a se. The objective of abuilding code is also to protect the public by accounting for the influence

38、 ofthe local environmental conditions on construction. For example, localauthorities may specify additional provis to account for such regionalconditions as earthquake, heavy snow, or tornados. National structural codesgenrally are incorporatedo local building codes.The American Concrete Institute (

39、 ACI ) Building Code covering the designof reinforced concrete buildings. It contains provis covering all aspectsof reinforced concrete manufacture, design, and construction. It includesspecifications on quality of materials,s on mixing and placing concrete,design amptions for theysis of continuous

40、structures, and equations forproportioning members for design for.All structures must be proportioned so they will not fail or deformexsively under anysible condition of service. Therefore it is importantt an engineer use great care inipating all the probable loads to whicha structure will be subjec

41、ted during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the for produced by wind, impact, shrinkage, temperature change, creep and supportsettlements, earthquake, and so forth.The load assote

42、d with the weight of the structure itself and its permanentcomponents is called the dead load. The dead load of concrete members, whichibstantial, should never be neglected in design compuions. The exacte been sized.magnitude of the dead load is not known accuray until membersSinome figure for the d

43、ead load must beused in compuions to size the. After a structure has beenmembers, its magnitude must be estimated atyzed, the members sized, and architecturals completed, the dead loadcan be computed more accuray. If the computed dead load is approximay equalto the initial estimate of its value ( or

44、 slightly less ), the design is complete,but if a significant difference exists betn the computed and estimated valuesof dead weight, the compuions should be revised using an improved value ofdead load. An accurate estimate of dead load is particularly important when spansare long, say over 75 ft (

45、22.9 m ), because dead load constitutes a major portion of the design load.Live loads assoted with building use are specific items of equipment andoccupants in a certain area of a building, building codes specify values ofuniform live for whiembers are to be designed.After the structure has been siz

46、ed for vertical load, it is checked for windin combination with dead and live load as specifiednot usually control the size of members in building lesshe code. Wind loads don 16 to 18 stories,but for tall buildings wind loadse significant and cause large fortodevelophe structures. Under these condit

47、ions economy can be achieved onlyby selecting a structural systemthe ground efficiently.t is able to transfer horizontal loadso钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。很多地区，包括，钢筋混凝土在工程建设中是主要的结构材料。钢筋混凝土建筑的普遍性源于和钢筋的广泛供应和混凝土的组成成分，砾石，沙子，水泥等，混凝土施工所需的技能相对简单，与其他形式的建设相比，钢筋混凝土更加经济。混凝土及钢筋混凝土用于桥梁、各种结构建筑、水池、电视塔、海洋石油勘探建筑

48、、工业建筑、大坝，甚至用于造船业。钢筋混凝土结构可能是现浇混凝土结构，在其最后位置建造，或者他们可能是在一家工厂生产混凝土预制件，再在施工现场安装。混凝土结构在设计上可能是普通的和多功能的，或形状和布局是奇想和艺术的。其他很少几种建材能够提供建筑和结构如此的通用性和广泛适用性。混凝土有较强的抗压力但抗拉力很弱。因此，混凝土，每当承受荷载时，或约束收缩或温度变化，引起拉应力，在超过抗拉强度时，裂缝开始发展。在素混凝土梁中，中和轴的弯矩是由在混凝土内部拉压力偶来抵抗作用荷载之后的值。这种梁当出现第一道裂缝时就突然完全地断裂了。在钢筋混凝土梁中，钢筋是那样埋置于混凝土中，以至于当混凝土开裂后弯矩平衡

49、所需的拉力由纲筋中产生。钢筋混凝土构件的建造包括以被建构件的形状支摸板。模型必须足够强大，以至于能够支承自重和湿混凝土的静水压力，工人施加的任何力量都适用于它，具体推车，风压力，等等。在混凝土的过程中，钢筋将被放置在摸板中。在混凝土硬化后，模板都将被移走。当模板被移走时，支撑将被安装来承受混凝土的重量直到它达到足够的强度来承受自重。设计师必须使混凝土构件有足够的强度来抵抗荷、载和足够的刚度来防止过度的挠度变形。除此之外，梁必须设计合理以便它能够被建造。例如，钢筋必须按构造设计，以便能在现场装配。由于当钢筋放入摸板后才浇筑混凝土，因此混凝土必须能够流过钢筋及摸板并完全充满摸板的每个角落。被建成的

50、结构材料的选择是混凝土，还是钢材、砌体，或木材，取决于是否有材料和一些价值决策。结构体系的选择是由建筑师或工程师早在设计的基础上决定的，考虑到下列：1.经济。常常首要考虑的是结构的总造价。当然，这是随着材料的成本和安装构件的必需劳动力改变的。然而，总投资常常更受总工期的影响，因为承包商和业主必须借款或以便完成建设，在建筑物竣工前他们从此项投资中将得不到任何回报。在一个典型的大型公寓或商业项目中，建筑成本的融资将是总费用的一个重要部分。因此，金融储蓄，由于快速施工可能多于抵消增加材料成本。基于这个原因，设计师可以采取任何措施规范设计来减轻削减的成本。在许多情况下，长期的经济结构可能比第一成本更重

51、要。因此，维修和耐久性是重要的考虑。2 .用于建筑与结构功能适宜的材料。钢筋混凝土体系经常让设计师将建筑与结构的功能相结合。混凝土被放置在塑性条件下借助于模板和表面加工来造出想要的形状和结构，这是它具有的优势。在提供成品楼或天花板表面时，这使得平板或其他形式的板作为受力构件。同样，钢筋混凝土墙壁能提供有吸引力的建筑表面，还有能力抵御重力、风力，或的。荷载。最后，大小和形状的选择是由设计师而不是由提供构件的标准决定3 .耐火性。建筑结构必须经受得住火灾的，并且当疏散及大火扑灭之时建筑物仍然保持不倒。钢筋混凝土建筑特殊的防火材料及其他构造措施情况下，自身具有1-3 个小时的耐火极限。钢结构或木结构

52、必须采取防火措施才能达到类似的耐火极限。4 .低。混凝土构件本身比结构钢或木材构件需要更少的维修。如果致密，尤其如此，加气混凝土已经被用于于大气中的表面，如果在设计中已经采取谨慎措施，以提供足够的排水和远离的结构。必须采取的特别预防措施是让混凝土接触到盐，如除冰化学品。5 .材料的供应。砂、碎石、水泥和混凝土搅拌设备是被非常广泛使用的，以及钢筋比结构钢更容易运到多数工地。因此，钢筋混凝土在偏远地区经常使用。另一方面，有一些可能会导致选择钢筋混凝土以外的材料。这些措施包括：1 .低抗拉强度。混凝土的抗拉强度是远低于其抗压强度（约 1 / 10 ） ，因此，混凝土易经受裂缝。在结构用途时，用钢筋承

53、受拉力，并限制裂缝宽度在允许的范围内来克服。不过，在设计和施工中如果不采取措施，这些裂缝可能会有碍观瞻，或可允许水的浸入。发生这种情况时，水或化学物质如道路除冰盐可能会导致混凝土的或污染。这种情况下，需要特别设计的措施。在水支挡结构这种情况下，需要特别的措施和/或预应力，以防止泄漏。2 .支摸。建造一个现浇结构包括三个步骤，在钢或木结构的施工中是遇不到的。这些都是（a）支摸 （b）拆摸（ c ） 安装支撑，直至其达到足够的强度以支承其重量。上述每个步骤，涉及劳动力和/或材料，在其他结构形式中，这是没有必要的。3 . 每 ，而其重量或量的相对低强度。该混凝土抗压强度大约是钢材抗压强度 5 至 10密度大约是钢材密度的 30 。因此，一个混凝土结构，与钢结构相比，需要较大的体积和较大重量的材料。因此，大跨度结构，往往建成钢结构。4 .时间依赖的量的变化。混凝土与钢进行大约同样数量的热膨胀和收缩时，有比较少量的钢材加热或冷却，因为钢与混凝土相比是一个较好的导体，钢结构比混凝土结构在更大程度上更易受温度变化