1、山東科技大學泰山科技學院學生畢業設計（論文）外文文獻翻譯Reinforced ConcreteCon crete and rein forced con crete are used as build ing materials in every coun try. In many, in clud ing the Un ited States an d Can ada, rein forced con crete is a dominant structural material in engin eered con structi on.The uni versal n ature of

2、rein forced con crete con structi on stems from the wide availability of rei nforci ng bars and the con stitue nts of con crete, gravel, sand, and cement, the relatively simple skills required in con crete con structi on, and the economy of rein forced con crete compared to other forms of con struct

3、i on. Con crete and rein forced con crete are used in bridges, build ings of all sorts un dergro und structures, water tan ks, televisi on towers, offshore oil explorati on and product ion structures, dams, and eve n in ships.Rein forcedcon crete structures may be cast-i n-placecon crete,con structe

4、d in their fin al locatio n, or they may be precast con crete produced in a factory and erected at the con structi on site. Con crete structures maybe severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engin eer

5、such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whe never loads, or restrai ned shri nkage of temperature changes, give rise to tensile stresses in excess of the tensilestrengthof the con crete. In a pla in con crete beam, the mome nts ab

6、out the n eutral axis due to applied loads are resisted by an internaltension-compressioncouple involving tension in the concrete. Such a beamfails very suddenly and completely when the first crack forms. In a reinforcedconcrete beam,steel bars are embedded in the con crete in such a way that the te

7、nsion forces n eeded for mome nt equilibrium after the con crete cracks can be developed in the bars.The con structi on of a rein forced con crete member invo Ives build ing a from of mold in the shape of the member being built. The form must be strong eno ugh to support both the weight and hydrosta

8、tic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies, wind, and so on. The reinforcement is placed in this form and held in place duri ng the con cret ing operati on. After the con crete has harde ned, the forms are removed. As the forms are removed, props of s

9、hores are in stalled to support the weight of the con crete un til it has reached sufficie nt strength to support the loads by itself.The designer must proportiona concrete memberfor adequate strengthto resist the loads and adequate stiffnessto prevent excessivedeflecti ons. In beam must be proporti

10、 oned so that it can be con structed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the con crete is placed in the form after the reinforcement is in place, the concrete must be able to flow around, between, and past the reinforcementto fill all

11、parts of the formcompletely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials andon a number of value decisions.The choice of structural system is made by thearchitect of engineer early in the design,based on the followi

12、ngcon siderati ons:1. Economy. Freque ntly, the foremost con sideratio n is the overall const of the structure. This is, of course, a fun cti on of the costs ofthe materials and the labor necessary to erect them. Frequently,however,the overall cost is affected as much or more by the overall con stru

13、cti on time since the con tractor and owner must borrow or otherwise allocate money to carry out the con struct ionand will not receive a retur n on thisinvestment untilthe buildingis ready for occupancy. In a typical largeapartme nt of commercial project, the cost of con struct ion financing will b

14、e a significantfraction of the total cost. As a result, financial savingsdue to rapid con structi on may more tha n offset in creased material costs. For this reas on, any measures the desig ner can take to sta ndardize the desig n and forming will gen erally pay off in reduced overall costs.In many

15、 cases the Ion g-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are importa nt con siderati on.2. Suitability of material for architectural and structuralfunction.A rein forced con crete system freque ntly allows the desig ner to comb

16、 ine the architectural and structural functions. Con crete has the adva ntage that it is placed in a plastic condition and is given the desired shapeand texture by meansof the forms and the finishingtechniques. This allowssuch elements ad flat plates or other types of slabs to serve as load-bearinge

17、lements while providing the finished floor and / or ceilingsurfaces. Similarly,rein forcedcon cretewalls can providearchitecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Fin ally, the choice of size of shape is governed by the designer and n

18、ot by the availability of standard manu factured members.3. Fire resista nee. The structure in a buildi ng must withsta nd theeffects of a fire and rema in sta nding while the build ing is evacuated and the fire is exti nguished. A con crete buildi ng in here ntly has a 1- to 3-hour fire rating with

19、out special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratin gs.4. Low maintenan ce. Con crete members in here ntly require less maintenance than do structural steel or timber members. This is particularly true if den se, air-e ntra

20、ined con crete has bee n used forsurfaces exposed to the atmosphere, and if care has bee n take n in the desig n to provide adequate drain age off and away from the structure. Special precauti ons must be take n for con crete exposed to salts such as deici ng chemicals.5. Availability of materials.S

21、and, gravel, ceme nt, and con cretemixi ng facilities are very widely available, and rein forci ng steel canbe tran sported to most job sites more easily tha n can structural steel. As a result, re in forced con crete is freque ntly used in remote areas.On the other hand, there are a nu mber of fact

22、ors that may cause one to select a material other tha n rein forced con crete. These in clude:1. Low tensile strength. The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to crack in g. In structural uses this is overcome by using r

23、ei nforceme nt to carry ten sile forces and limit crack widths to with in acceptable values. Un less care is take n in desig n and con struct ion, however, these cracks maybe unsightly or mayallow penetration of water. Wherthis occurs, water or chemicals such as road deicing salts may cause deterior

24、ation or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and /of prestress ing are required to preve nt leakage.2. Forms and shori ng.The con structi on of a cast-i n-place structureinvo Ives three steps not enco

25、un tered in the con struct ion of steel or timber structures. These are ( a ) the con struct ion of the forms, ( b ) the removal of these forms, and (c) propp ing or shori ng the new con crete to support its weight until its strength is adequate. Each of these steps invoIves labor and / or materials

26、, which are not necessary with other forms of con structi on.3. Relatively low strengthper unitof weight for volume. Thecompressive strength of concrete is roughly 5 to 10%that of steel, while its unit den sity is roughly 30% that of steel. As a result, a con cretestructure requires a larger volume

27、and a greater weight of material than does a comparable steel structure. As a result, Iong-span structures are ofte n built from steel.4. Time-depe ndent volume cha nges. Both con crete and steelundergo-approximately the same amount of thermal expansionandcon tracti on. Because there is less mass of

28、 steel to be heated or cooled, and because steel is a better con crete, a steel structure is gen erallyaffected by temperature cha nges to a greater exte nt tha n is a con crete structure.On the other hand, con crete un dergoes fryi ng shri nkage, which,ifrestrained,may cause deflections or cracking

29、. Furthermore,deflecti ons will tend to in crease with time, possibly doubli ng, due to creep of the con crete un der susta ined loads.engineeringand architecturecon crete for structures and requires basic knowledge ofIn almost every branch of civil extensive use is made of reinforced foundations.En

30、gineers and architects rein forced con crete desig n throughout their professi onal careers. Muchof this text is directly concerned with the behavior and proportioningof components that makeup typical reinforcedconcrete structures-beams, colu mns, and slabs. Once the behavior of these in dividual el

31、eme nts is un derstood, the desig ner will have the backgro und to an alyze and desig n a wide range of complex structures, such as foun datio ns, buildi ngs, and bridges, composed of these eleme nts.Si nee rei nforced concrete is a no homogeneous material that creeps, shri nks, and cracks, its stre

32、sses cannot be accurately predicted by the traditional equations derived in a course in strength of materials forhomoge neous elastic materials. Much of rein forced con crete desig n in therefore empirical, i.e., design equations and design methods are based on experime ntal and time-proved resultsi

33、n steadof being derivedexclusively from theoretical formulati ons.A thorough un dersta nding of the behavior of rein forced con crete will allow the desig ner to con vert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete sdesirable characteri

34、stics, its high compressive stre ngth, itsfireresista nee, and its durability.Concrete, a stone like material, is madeby mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives (that modify properties ) into a workable mixture. In its un harde ned or pla

35、stic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile stre ngth and therefore cracks easily. Because unrein forced con crete is brittle, it c

36、annot undergo large deformations under load and fails sudde nly-without warni ng. The additi on fo steel rein forceme nt to the con crete reduces the n egative effects of its two prin cipalin here ntweaknesses, its susceptibility to cracking and its brittleness.Whentherein forceme nt is stro ngly bo

37、n ded to the con crete, a strong, stiff, and ductile con struct ionmaterial is produced. This material, calledrei nforced con crete,is used exte nsively to con struct foun dati ons,structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and buil

38、ding products. Twoother characteristics of concrete that are present even when concreteisrein forced are shri nkage and creep, but the n egative effects of these properties can be mitigated by careful desig n.A code is a set tech ni cal specificati ons and sta ndards that con trol importa nt details

39、 of desig n and con struct ion. The purpose of codes it produce structures so that the public will be protected from poor of in adequate and con struct ion.Two types f coeds exist. One type, called a structural code, is orig in ated and con trolled by specialists whoare concerned with the proper use

40、 of a specific material or who are involved with the safe design of a particular class of structures.The sec ond type of code, called a build ing code, is established to cover con struct ion in a give n region, ofte n a city or a state. The objective of a build ing code is also to protect the public

41、 by acco un ti ng for the in flue nee of the local en vir onmen tal con diti ons on con structi on. For example, local authorities may specifyadditionalprovisions toaccount for such regionalconditionsas earthquake, heavy snow, ortorn ados. Nati onal structural codes gen rally are in corporated into

42、local build ing codes.The American Concrete Institute ( ACI ) Building Code covering the desig n of rein forcedcon crete build in gs. It contains provisi ons coveri ngall aspects of re in forced con crete manu facture, desig n, and con structi on. It includes specificationson quality of materials, d

43、etails on mixing andplacing concrete,design assumptions for the analysisof continuousstructures, and equati ons for proporti oning members for desig n forces.All structures must be proportioned so they will not fail or deform excessively un der any possible con diti on of service. Therefore it is im

44、portant that an engineer use great care in anticipatingall the probableloads to which a structure will be subjected during its lifetime.Although the desig n of most members is con trolled typically by dead and live load acting simultaneously,considerationmust also be given tothe forces produced by w

45、ind, impact, shrinkage, temperature change, creep and support settleme nts, earthquake, and so forth.The load associated with the weight of the structure itself and its perma nent comp onents is called the dead load. The dead load of con crete members, which is substantial,should never be neglected

46、in designcomputations. The exact magnitude of the dead load is not known accurately until members have been sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the memberssized, an

47、d architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initialestimate of its value ( or slightly less ), the design is complete,but if a significantdifferenee exists between the computed and estimatedvalues of dead w

48、eight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly importa nt whe n spa ns are long, say over 75 ft ( 22.9 m ),because dead load con stitutes a major porti on of the desig n load.Live loads associated with building use ar

49、e specific items of equipme nt and occupa nts in a certa in area of a build ing, buildi ng codes specify values of un iform live for which members are to be desig ned.After the structure has bee n sized for vertical load, it is checkedfor wi nd in comb in ati on with dead and live load as specified

50、in the code. Wind loads do not usually con trol the size of members in buildi ng lessthan 16 to 18 stories, but for tall buildings wind loads becomesignificant and cause large forces to develop in the structures.Under theseconditionseconomycan be achieved only by selectinga structural systemthat is

51、able to tran sfer horiz on tal loads into the ground efficie ntly.鋼筋混凝土在每一個國家，混凝土及鋼筋混凝土都被用來作為建筑材料。很多地區，包括美國和加拿大，鋼筋混凝土在工程建設中是主要的結構材料。 鋼筋混凝土建筑 的普遍性源于鋼筋的廣泛供應和混凝土的組成成分，礫石，沙子，水泥等，混凝 土施工所需的技能相對簡單，與其他形式的建設相比，鋼筋混凝土更加經濟。混 凝土及鋼筋混凝土用于橋梁、各種地下結構建筑、水池、電視塔、海洋石油勘探 建筑、工業建筑、大壩，甚至用于造船業。鋼筋混凝土結構可能是現澆混凝土結構， 在其最后位置建造，或者他們

52、可能 是在一家工廠生產混凝土預制件， 再在施工現場安裝。混凝土結構在設計上可能 是普通的和多功能的，或形狀和布局是奇想和藝術的。其他很少幾種建材能夠提 供建筑和結構如此的通用性和廣泛適用性。混凝土有較強的抗壓力但抗拉力很弱。因此，混凝土，每當承受荷載時，或 約束收縮或溫度變化，引起拉應力，在超過抗拉強度時，裂縫開始發展。在素混 凝土梁中，中和軸的彎矩是由在混凝土內部拉壓力偶來抵抗作用荷載之后的值。 這種梁當出現第一道裂縫時就突然完全地斷裂了。 在鋼筋混凝土梁中，鋼筋是那 樣埋置于混凝土中，以至于當混凝土開裂后彎矩平衡所需的拉力由綱筋中產生。鋼筋混凝土構件的建造包括以被建構件的形狀支摸板。模型必

53、須足夠強大， 以至于能夠支承自重和濕混凝土的靜水壓力，工人施加的任何力量都適用于它， 具體的手推車，風壓力，等等。在混凝土的運作過程中，鋼筋將被放置在摸板中。 在混凝土硬化后，模板都將被移走。當模板被移走時，支撐將被安裝來承受混凝 土的重量直到它達到足夠的強度來承受自重。設計師必須使混凝土構件有足夠的強度來抵抗荷、載和足夠的剛度來防止過 度的撓度變形。除此之外，梁必須設計合理以便它能夠被建造。例如，鋼筋必須 按構造設計，以便能在現場裝配。由于當鋼筋放入摸板后才澆筑混凝土， 因此混 凝土必須能夠流過鋼筋及摸板并完全充滿摸板的每個角落。被建成的結構材料的選擇是混凝土，還是鋼材、砌體，或木材，取決于

54、是否 有材料和一些價值決策。結構體系的選擇是由建筑師或工程師早在設計的基礎上 決定的，考慮到下列因素：1. 經濟。常常首要考慮的是結構的總造價。當然，這是隨著材料的成本和安裝構件的必需勞動力改變的。然而，總投資常常更受總工期的影響，因為承包商和業主必須借款或貸款以便完成建設，在建筑物竣工前他們從此項投資中將得不 到任何回報。在一個典型的大型公寓或商業項目中， 建筑成本的融資將是總費用 的一個重要部分。因此，金融儲蓄，由于快速施工可能多于抵消增加材料成本。 基于這個原因，設計師可以采取任何措施規范設計來減輕削減的成本。在許多情況下，長期的經濟結構可能比第一成本更重要。因此，維修和耐久 性是重要的

55、考慮因素。2. 用于建筑與結構功能適宜的材料。鋼筋混凝土體系經常讓設計師將建筑與結構的功能相結合。混凝土被放置在塑性條件下借助于模板和表面加工來造出 想要的形狀和結構，這是它具有的優勢。在提供成品樓或天花板表面時，這使得平板或其他形式的板作為受力構件。 同樣，鋼筋混凝土墻壁能提供有吸引力的建 筑表面，還有能力抵御重力、風力，或地震荷載。最后，大小和形狀的選擇是由 設計師而不是由提供構件的標準決定的。3. 耐火性。建筑結構必須經受得住火災的襲擊，并且當人員疏散及大火撲 滅之時建筑物仍然保持不倒。鋼筋混凝土建筑特殊的防火材料及其他構造措施情 況下，自身具有1-3個小時的耐火極限。鋼結構或木結構必須

56、采取防火措施才能 達到類似的耐火極限。4低維護。混凝土構件本身比結構鋼或木材構件需要更少的維修。如果致 密，尤其如此，加氣混凝土已經被用于暴露于大氣中的表面，如果在設計中已經采取謹慎措施，以提供足夠的排水和遠離的結構。必須采取的特別預防措施是讓 混凝土接觸到鹽，如除冰化學品。5.材料的供應。砂、碎石、水泥和混凝土攪拌設備是被非常廣泛使用的， 以及鋼筋比結構鋼更容易運到多數工地。 因此，鋼筋混凝土在偏遠地區經常使用。另一方面，有一些因素可能會導致選擇鋼筋混凝土以外的材料。這些措施包括：1 .低抗拉強度。混凝土的抗拉強度是遠低于其抗壓強度（約1 / 10 ），因此，混凝土易經受裂縫。在結構用途時，

57、用鋼筋承受拉力，并限制裂縫寬度在 允許的范圍內來克服。不過，在設計和施工中如果不采取措施，這些裂縫可能會 有礙觀瞻，或可允許水的浸入。發生這種情況時， 水或化學物質如道路除冰鹽可 能會導致混凝土的惡化或污染。這種情況下，需要特別設計的措施。 在水支擋結 構這種情況下，需要特別的措施和/或預應力，以防止泄漏。2.支摸。建造一個現澆結構包括三個步驟，在鋼或木結構的施工中是遇不 到的。這些都是（a）支摸（b）拆摸（c ）安裝支撐，直至其達到足夠的強 度以支承其重量。上述每個步驟，涉及勞動力和 /或材料，在其他結構形式中， 這是沒有必要的。3 .每單位重量或量的相對低強度。該混凝土抗壓強度大約是鋼材抗壓強度5至10 % ,而其單位密度大約是鋼材密度的 30 %。因此，一個混凝土結構， 與鋼結構相比，需要較大的體積和較大重量的材料。因此，大跨度結構，往往建 成鋼結構。4 .時間依賴的量的變化。混凝土與鋼進行大約同樣數量的熱膨脹和收縮時， 有比較少量的鋼材加