畢業(yè)設(shè)計(jì)外文文獻(xiàn)翻譯(土木工程類)

1、 PAGE PAGE 11中文翻譯1.1素混凝土是由水泥、水、細(xì)骨料、粗骨料(碎石或；卵石、空氣，通常還有其他外加劑等經(jīng)過(guò)凝固硬化而成。將可塑的混凝土拌合物注入到模板內(nèi),并將其搗實(shí)，然后進(jìn)行養(yǎng)護(hù)，以加速水泥與水的水化反應(yīng)，最終獲得硬化的混凝土。其最終制成品具有較高的抗壓強(qiáng)度和較低的抗拉強(qiáng)度。其抗拉強(qiáng)度約為抗壓強(qiáng)度的格外之一。因此，截面的受拉區(qū)必需配置抗拉鋼筋和抗剪鋼筋以增加鋼筋混凝土構(gòu)件中較弱的受拉區(qū)的強(qiáng)度。.將鋼筋混凝土這種非均質(zhì)截面的兩種組成部用，配置鋼筋后，可以作為任何結(jié)構(gòu)體系的主要構(gòu)件.基礎(chǔ)，大體積混凝土水壩或者連續(xù)延長(zhǎng)已澆筑完畢并且已經(jīng)凝固的混凝土等。對(duì)于,當(dāng)模板清理潔凈后應(yīng)當(dāng)在其上

2、涂油，鋼筋表面的銹及其他有害物質(zhì)也應(yīng)當(dāng)被清除潔凈。澆筑基礎(chǔ)前，應(yīng)將坑底土夯實(shí)并用水浸濕6 英寸，以免土壤從新澆的混凝土中吸取水分.方向分層澆筑,過(guò)分的振搗將導(dǎo)致骨料離析和混凝土泌漿等現(xiàn)象，因而是有害的。50F這將有損與混凝土的強(qiáng)度，同時(shí)也會(huì)影響到水泥水化作用的充分進(jìn)行。截面時(shí)需要進(jìn)行試算并作調(diào)整,依據(jù)施工現(xiàn)場(chǎng)條件、混凝土原材料的供應(yīng)狀況、業(yè)截面，因此設(shè)計(jì)時(shí)第一次接受的數(shù)值將導(dǎo)致一系列的試算與調(diào)整工作.專用程序的使用,使這種設(shè)計(jì)方法更為簡(jiǎn)捷有效，而傳統(tǒng)的方法則是把鋼筋混凝土的復(fù)核與單純的設(shè)計(jì)分別進(jìn)行處理。1。2一牢靠而又最新的資料可以從制造廠商處獲得.（挖方),并把它傾。為了降低土方工程費(fèi)用，填

3、方量應(yīng)當(dāng)?shù)扔谕诜阶詈玫姆桨?。土機(jī)所推運(yùn)的圖的數(shù)量最多，只是運(yùn)輸距離很短.拉鏟挖土機(jī)的缺點(diǎn)是只能挖比它本身低的土,不能施加壓力挖入壓實(shí)的土壤內(nèi)，不能在陡坡上挖土，而且挖。卸都不精確。危急的，而對(duì)拉鏟挖土機(jī)則是不行能的.每種機(jī)械設(shè)備應(yīng)當(dāng)進(jìn)行最適合它的性能的土機(jī)最適用，但其卸料半徑比起裝有正鏟的同一挖土機(jī)的卸料半徑則要小很多. 機(jī)械本身下面的土）,需要時(shí)可以將土運(yùn)至幾百米遠(yuǎn)，然后卸土并在卸土的過(guò)程中把土大致鏟平。在挖掘硬土?xí)r,人們發(fā)覺(jué)在開(kāi)挖場(chǎng)地經(jīng)常用一輛助推拖拉機(jī)(輪式或助推拖拉機(jī)就回到開(kāi)挖的地點(diǎn)去掛念下一臺(tái)鏟運(yùn)機(jī).8 m m）,4304.5m。特殊型式的翻斗車4 m0.5 m的鉸接式翻斗車.必需記

4、住翻被稱為后卸卡車。1.3規(guī)范的主要目的是供應(yīng)一般性的設(shè)計(jì)原理和計(jì)算方法，以便驗(yàn)算結(jié)構(gòu)的平安 ,通常把它構(gòu)的破壞概率（危急率)成反比。,通常有兩種類型的極限狀態(tài),即：(1）強(qiáng)度極限狀態(tài)，它相當(dāng)于結(jié)構(gòu)能夠達(dá)到的最大承載力量。其例子包括結(jié)構(gòu)的局部屈曲和整體不穩(wěn)定性;某此界面失效,隨后結(jié)構(gòu)轉(zhuǎn)變?yōu)闄C(jī)構(gòu)；疲憊破壞;引起結(jié)構(gòu)幾何外形顯著變化的彈性變形或塑性變形或徐變;敏感性。（2）使用極限狀態(tài)，它對(duì)應(yīng)著結(jié)構(gòu)的使用功能和耐久性.器例子包括結(jié)構(gòu)失穩(wěn)之前的過(guò)大變形和位移；早期開(kāi)裂或過(guò)大的裂縫;較大的振動(dòng)和腐蝕。依據(jù)不同的平安度條件,可以把結(jié)構(gòu)驗(yàn)算所接受的計(jì)算方法分成：（1)確定性的方法,在這種方法中,把主要參數(shù)

5、看作非隨機(jī)參數(shù).（2）概率方法，在這種方法中,主要參數(shù)被認(rèn)為是隨機(jī)參數(shù)。 經(jīng)過(guò)按規(guī)定的平安系數(shù)進(jìn)行折減后的材料強(qiáng)度作比較。衡量的.由理論分析確定的這一最大強(qiáng)度應(yīng)不小于結(jié)構(gòu)承受計(jì)算荷載所算得的強(qiáng)度（極限狀態(tài)).計(jì)算荷載等于分別乘以荷載系數(shù)的活載與恒載之和。（使用)（使）相比較。依據(jù)前兩種方法和后兩種方法的四種可能組合，我們可以得到一些有用的計(jì)算方法。通常接受下面兩種計(jì)算方法：確定性的方法，這種方法接受容許應(yīng)力.概率方法，這種方法接受極限狀態(tài).,然后將這些隨機(jī)平安系數(shù)組合成確定的平安系數(shù)。概率法取決于：（1)制作和安裝過(guò)程中材料強(qiáng)度的隨機(jī)分布（整個(gè)結(jié)構(gòu)的力學(xué)性能數(shù)值的分散性）;（2）截面和結(jié)構(gòu)幾何

6、尺寸的不確定性（由結(jié)構(gòu)制作和安裝造成的誤差和缺陷而引起的);對(duì)作用在結(jié)構(gòu)上的活載和恒載的猜測(cè)的不確定性;所接受的近似計(jì)算方法有關(guān)的不精確性（實(shí)際應(yīng)力與計(jì)算應(yīng)力的偏差)。 此外，概率理論意味著可以基于下面幾個(gè)因素來(lái)確定允許的危急率，例如:建筑物的重要性和建筑物破壞造成的危害性；由于建筑物破壞使生活受到威逼的人數(shù);修復(fù)建筑的可能性；建筑物的預(yù)期壽命。全部這些因素均與經(jīng)濟(jì)和社會(huì)條件有關(guān)，例如：建筑物的初始建設(shè)費(fèi);建筑物使用期限內(nèi)的折舊費(fèi)；(3）由于建筑物破壞而造成的物質(zhì)和材料損失費(fèi)；在社會(huì)上造成的不良影響;精神和心理上的考慮。就給定的平安系數(shù)而論,全部這些參數(shù)的確定都是以建筑物的最佳成本為依據(jù)的。但

7、是，應(yīng)當(dāng)考慮到進(jìn)行全概率分析的困難.對(duì)于這種分析來(lái)說(shuō),應(yīng)當(dāng)了解活載及(半概率方法。外文翻譯Reinforced ConcretePlain concrete is formed from a hardened mixture of cement ,water ,fine aggregate, orgravel)，airandoftenotheradmixtures.Theplasticmix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical

8、hydration reaction lf the cement/water mix， resulting in hardenedconcreteThe finished product has high compressive strength, and low resistance totension， such that its tensile strength is approximately one tenth lf its compressivestrength。 Consequently， tensile and shear reinforcement in the tensil

9、e regions ofsections has to be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from thehomogeneity of standard wood or steel sections that requires a modified approach to the basicprincipl

10、esofstructuraldesign.Thetwocomponentsoftheheterogeneousreinforced concrete section are to be so arranged and proportioned that optimal use ismade of the materials involved. This is possible because concrete can easily be given anydesired shape by placing and compacting the wet mixture of the constit

11、uent ingredients are properly proportioned， the finished product becomes strong, durable, and, incombination with the reinforcing bars， adaptable for use as main members of anystructural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it

12、 is a column, a bean ， a wall， a slab， a foundation。 a masscolumns, or an extension of previously placed and hardened concrete。 For beams，columns, and walls, the forms should be well oiled after cleaning them, and the should be cleared of rust and other harmful materialsIn foundations, theearth shou

13、ld be compacted and thoroughly moistened to about 6 in. in depth to avoidabsorption of the moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-drivenvibrators of either the immersion or external type, as the

14、 case requires， unless it isplaced by pumping。 It must be kept in mind ， however， that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures 50F。 Itisnecessarytomain

15、tainsuchaconditioninorderthatthe chemicalhydrationreactioncantakeplaceIfdryingistoorapidsurface duetocrackingaswellasthefailuretoattainfullchemicalhydration.It is clear that a large number of parameters have to be dealt with in proportioning a element, such as geometrical width，depth，area of reinfor

16、cement，strain, concrete strain， steel stress， and so on. Consequently, trial and adjustmentis necessary in the choice of concrete sections, with assumptions based on conditions at site， availability of the constituent materials， particular demands of the owners, architectural and headroomrequirement

17、s, the applicable codes, and environmental reinforced concrete is often a siteconstructed composite, in contrast to the standard millfabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be

18、 analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive attherequiredsection ，thefirstdesigninputstepgeneratesintoaseriestrial-and-adjustmentanalyses。The trial-and adjustment procedures for the ch

19、oice of a concrete section lead to theconvergence of analysis and design. Hence every design is an analysis once a trialsectionis chosen。 The availability of handbooks， charts, and personal computers andprograms supports this approach as a more efficient, compact, and speedy instructional method com

20、pared with the traditional approach of treating the analysis of reinforcedconcrete separately from pure design.EarthworkBecause earthmoving methods and costs change more quickly than those in anyother branch of civil engineering，this is a field where there are real opportunities for theenthusiast. I

21、n 1935 most of the methods now in use for carrying and excavating earthwith rubbertyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab， though they are still widely used are

22、 only a few of the many current methods。To keep his knowledge of earthmoving equipment up to date an engineer musttherefore spend tine studying modern machines. Generally the only reliable up-todateinformation on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmovi

23、ng means cutting into ground where its surface is too high（ cuts ), and dumping the earth in other places where the surface is too low ( fillsToreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of eq

24、ual volume so as toreduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more thananythingelsewhich decidesitscheapness Fromthe availablemaps ahdlevels theengineering must try to reach as man

25、y decisions as possible in the drawing office bydrawing cross sections of the earthwork. On the site when further information becomes availablehecanmakechangesinjissectionsandlayout，butthedrawinglfficeworkwillnot have been lost. It will have helped him to reach the best solution in the shortest time

26、。The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine 。 This is not always possible ， but when it canbe done it isideal, being both quick and cheap。 Draglines, bulldozers and face shovels an do this。Thelargestradiusisobtainedwiththedragline

27、，andthelargesttonnageofearthismoved bulldozerthough only over short distances.The disadvantages of the dragline arethat it must dig below itself， it cannot dig with force into compacted material, it cannotdig on steep slopws,and its dumping and digging are not accurate。Face shovels are between bulld

28、ozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a draglineEach piece of equipment should be level of their tracks and for deep

29、digs in compact is most usefulbut its dumping radius is considerably less than thatofthe same escavator fitted with a face shovel。Rubbertyred bowl scrapers are indispensable for fairly level digging where thedistance of transport is too much tor a dragline or face shovel. They can dig the material d

30、eeply （butonly belowthemselves)to afairlyflatsurface, carryithundredsofmeters and level it roughly during the dumping。For hard digging it isoften found economical to keep a pusher tractor ( wheeled or tracked） on the diggingsite, to push each scraper as it returns to dig 。 As soon as the scraper is

31、full,the pusher tractorreturns to the beginning of the dig to heop to help the nest scraper。Bowl scrapers are often extremely powerful machines；many makers build scrapersof8 cubicmetersstruckcapaciy which carry10 mheape。 The largestself-propelraperareof19mstruccapacit(25mheaped）andy driven by a trac

32、tor engine of 430 horse-powers.Dumpers areprobablthecommonest rubber-tyrranspoinctheycanalsoconveniently be used for carrying concrete or other buildngpeaavethe earth container over the front axle on lrybeels, and the containertips forwards on most yphough in articulated dumpers the direction of tip

33、 can be standard types are of aumSpecial types include teing dumper ofup to 4 m and the articulated type ofThe distinction between dumpersand dump trucks must be remembered .dumpers tip forwards and the driver sits behindDump trucks are strengthened tipping lorries, infrontlftheloadandtheloadisdumpe

34、d behindhim， sotheyaresometimescalledrear-dumptrucks2。3 Safety of Structurescomputational methods in order to verify safety oTtucy factor ”, which according to modern trends is independent of the nature and combination of the materuse， can usually be defined as the ratio between the onoatio is also

35、proportionaltotheinverseoftheprobabilityriskoffailureofthestructure.Failure has to be considered not only as overall collapse of the structure butunserviceabiliy ccording to a more precise. Common deinihe reachingdesignedforTherearetwocategoriesoflimitstate（1）Ultimatelimitsate,which correspondsto th

36、ehighestvalueof the structure; failure of some sections and subsequent transformation of the structuremechanism； failuyfatige elastrplastideformatioorcreepthacauseasubstantihangeofthegeometryofthestructurndsensitivifthestructuo alternating ladto fire and to explsions（2)Serviclimistateswhicharefuncti

37、onoftheuseanddurabilifthe structureExamplesincludeexcessivedeformationsands instabiitearly or excessive rarge vibratonand corrosonComputational methods used to verify structures with respect to the different safetyconditions can be separated into:Deterministicmethods,inwhichthemainparametersareconsi

38、derednonrandom parameters. parameters.Alternatively， with respect to the different use of factors of safety, computationalmethods can be separated into:（1）Allowable stress method, in which the stresses computed under maximumloads are compared with the strength of the material reduced by given safety

39、 factors. (2)Limitstatesmethod,inwhichthestructuremaybeproportionedonthebasisofits maximum strength。 This strength, as determined by rational analysis, shall not beless than that required to support a factored load equalto thesum ofthefactoredliveload and dead load ( ultimate state 。The stresses cor

40、responding to working（ service ) conditions with unfactored liveanddeadloadsarecompared withprescribedvalues （servicelimit state ）.Fromthefour possible combinations of the first two and second two methods, we can obtain some usefulcomputational methods. Generally， two combinations prevail:(1)determi

41、nisticmethods, which make use of allowable stresses。（2)Probabilistic methods, which make use of limit states。The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then combinedto define t

42、he safety factor。 probabilistic approaches depend upon :（1） Random distribution of strength of materials with respect to the conditionsof fabrication and erection ( scatter of the values of mechanical properties through out thestructure );（2)Uncertainty of the geometry of the cross-section sand of t

43、he structure( faults and imperfections due to fabrication and erection of the structure ；(3）structure;Uncertainty of the predicted live loads and dead loads acting on the（4)Uncertainty related to the approximation of the computational method used（ deviation of the actual stresses from computed stresses ).Furthermore， probabilistic theories mean that the allowable risk can be based onseveralfactors， such as ：(1) Importance of the