道路工程毕业设计外文翻译---公路线形设计

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土木工程专业毕业设计外文文献及翻译

土木工程专业毕业设计外文文献及翻译Here are two examples of foreign literature related to graduation design in the field of civil engineering, along with their Chinese translations:1. Foreign Literature:Title: "Analysis of Structural Behavior and Design Considerations for High-Rise Buildings"Author(s): John SmithJournal: Journal of Structural EngineeringYear: 2024Abstract: This paper presents an analysis of the structural behavior and design considerations for high-rise buildings. The author discusses the challenges and unique characteristics associated with the design of high-rise structures, such as wind loads and lateral stability. The study also highlights various design approaches and construction techniques used to ensure the safety and efficiency of high-rise buildings.Chinese Translation:标题：《高层建筑的结构行为分析与设计考虑因素》期刊：结构工程学报年份：2024年2. Foreign Literature:Title: "Sustainable Construction Materials: A Review of Recent Advances and Future Directions"Author(s): Jennifer Lee, David JohnsonJournal: Construction and Building MaterialsYear: 2024Chinese Translation:标题：《可持续建筑材料：最新进展与未来发展方向综述》期刊：建筑材料与结构年份：2024年Please note that these are just examples and there are numerous other research papers available in the field of civil engineering for graduation design.。

毕业设计外文翻译译文

1 工程概论1.1 工程专业1.2 工业和技术1.3 现代制造业工程专业1 工程行业是历史上最古老的行业之一。

如果没有在广阔工程领域中应用的那些技术，我们现在的文明绝不会前进。

第一位把岩石凿削成箭和矛的工具匠是现代机械工程师的鼻祖。

那些发现地球上的金属并找到冶炼和使用金属的方法的工匠们是采矿和冶金工程师的先祖。

那些发明了灌溉系统并建造了远古世纪非凡的建筑物的技师是他们那个时代的土木工程师。

2 工程一般被定义为理论科学的实际应用，例如物理和数学。

许多早期的工程设计分支不是基于科学而是经验信息，这些经验信息取决于观察和经历，而不是理论知识。

这是一个倾斜面实际应用的例子，虽然这个概念没有被确切的理解，但是它可以被量化或者数字化的表达出来。

3 从16、17世纪当代初期，量化就已经成为科学知识大爆炸的首要原因之一。

另外一个重要因素是实验法验证理论的发展。

量化包含了把来源于实验的数据和信息转变成确切的数学术语。

这更加强调了数学是现代工程学的语言。

4 从19世纪开始，它的结果的实际而科学的应用已经逐步上升。

机械工程师现在有精确的能力去计算来源于许多不同机构之间错综复杂的相互作用的机械优势。

他拥有能一起工作的既新型又强硬的材料和巨大的新能源。

工业革命开始于使用水和蒸汽一起工作。

从此使用电、汽油和其他能源作动力的机器变得如此广泛以至于它们承担了世界上很大比例的工作。

5 科学知识迅速膨胀的结果之一就是科学和工程专业的数量的增加。

到19世纪末不仅机械、土木、矿业、冶金工程被建立而且更新的化学和电气工程专业出现了。

这种膨胀现象一直持续到现在。

我们现在拥有了核能、石油、航天航空空间以及电气工程等。

每种工程领域之内都有细分。

6 例如，土木工程自身领域之内有如下细分：涉及永久性结构的建筑工程、涉及水或其他液体流动与控制系统的水利工程、涉及供水、净化、排水系统的研究的环境工程。

机械工程主要的细分是工业工程，它涉及的是错综复杂的机械系统，这些系统是工业上的，而非单独的机器。

道桥专业毕业设计外文翻译----沥青路面

专业外文翻译原文road surface of pitch1 Debulk1.1 SummaryGood pitch road surface quality is it reflect , appear any quality defect will all that has been achieved has come to nothing in rolling through rolling to want. The durable performance of meeting pitch road surface of the structure demand is affected by two indexes mainly, namely the mixture and debulk designed. In these two indexes , lack any durable performance that can't ensure the pitch road surface , if insufficient debulk, optimum mixture that design will reduce serviceability , pitch of road surface, and good debulk can improve the result of a kind of nonstandard mixture effectively . So, debulk is considered to influence one of the most important factors of durable performance of road surface of pitch .Debulk course to reduce pitch course , air vent of content in the mixture, for solid particle stemming and orientating among one viscoplasticity medium course this, in the form of forming a kind of closely more knit and more effective particle to arrange. This course only takes place under the construction state in theory, but not under the traffic condition.1.2 Impact on debulk of composition material on the pitch road surface1.2.1collects material performancein order to reach the ideal solidity of pressing, it is very important to collect material and detailed some nature of collecting material thickly: Such as the particle form, raised angle , the absorbing water rate and surface are constructed, grade mix mixture most heavy to collect material size , thick to collect material proportion , consumption and type ,etc. , consumption of sand and powder of ore pigeonhole to pitch mixture solidity have direct influence.Under the same situation as other indexes , collect material one grade of mixture or disconnected grade mixed and mix mixture than exchanging debulk more than the single size from thick to the detailed even grade of mixture mixed , thick to collectmaterial proportion heavy pitch mixture, must increase the strength of keeping notably , could obtain the necessary space rate . On the other hand, many sand, or detailed grade buy bituminous concrete to be very much easy to be plastic, this kind of mixture is still difficult to reach proper closely knit degree. The pitch mixture of much sand tends towards pushes and shoves and difficult with debulking under debulk function . The different kinds of packing has remarkable influence on debulk of the pitch mixture, according to survey, in a situation that other conditions are the same, ordinary silicate packing than lime stone ore powder pitch mixture and cement stone pitch mixture easy debulk bituminous concrete, pitch mixture total hole rate too very heavy difference have behind the shaping, 8% , 9.1% , 12% respectively.1.2.2pitch viscidity influencepitch viscidity influence pitch mixture strength degree, and can debulk nature have something to do with mixture. At the mixture, high viscidity can pin down particle move often as debulk pitch, if pitch viscidity too low, is it collect material to be particle easy to move and push and shove in real time to press. When pitch mixture temperature is higher, pitch is it is it collect material particle rub lubricant of obstruction to overcome to make, when the mixture has already been cooled, the pitch makes and combines the combinationmaterial which is collected the material particle. Generally speaking, in fixed 135 pitch being viscidity high,resistance, mixture of person who reduces space the heavier. So use high viscidity at the pitch , adopt higher debulk temperature to reduce viscidity promote pitch road surface but debulk essential means. Show according to materials data give temperature definitely , low drip of viscidity educate than high closely knit high degree that pitch reach of viscidity, through rise debulk temperature, high viscidity drip is it can reach high solidity of pigeonholing as low viscidity pitch to educate. Therefore understand debulk state , pitch of viscidity under the temperature to promote pitch road surface good debulk there are important meanings.1.2.3 performance of mixture influencein fact, performance , pitch of mixture, influence degree, road surface of debulk the heaviest to pitch, the influence than simple to collect material or drip breedobvious even. When pitch consumption is lower in the pitch mixture easy to is it do astringent , coarse mixture to form, often difficult debulk; When pitch consumption is too great, can form and lubricate the mixture excessivly , make the mixture under the function of the road roller, form unstable and can fracture ing , mixture suffused with the oil after the traffic is open; For lower than best pitch mixture of consumption, can through increase efficiency , debulk of course reduce the space rate, reach a kind of satisfaction; But if pitch consumption at the optimum value of higher thanning , press real-time , can't prevent out of shape limit , pitch of mixture from almost; Secondly , collect material water content meet the requirement of norm minimum while drying, such wet pitch mixture, present the inclination moved in the course of debulk, it is very difficult for the result to press worker.1.3 Temperature impact on pitch roadsurface debulk pitch debulk performance , mixture of road surface receive match ratio design, influence of factor, variety of pitch and temperature ,etc. of debulk, it is the most influential but with debulk temperature. As everyone knows, the properties of pitch and pitch mixture are very sensitive to temperature, is it can know (125C1130 ) in the same grade is it under the mixture , roll rising of temperature at the same time to mix to test. Mixture try on pieces of density increase , air rate reduce , until a certain temperature (145 1150 ) , mixture try on a density up to most heavy, at the same time the air rate is dropped to minimumly . If is it rise to continue under temperature this, can make density reduce, atmosphere rate increases. It is obvious temperature of mixture on the low side on the high side , will influence density and air rate , pitch of mixture (pigeonhole the solidity). The temperature of the pitch mixture is very important too in debulk of the construction site mixture. The temperature of the mixture has already become one of the two major factors influencing the solidity of high pressure of construction site and low air rate. Dark- Kui expressway layers of grains of type in being thick for 4cm the pitch. Construct location windy (4-5), organize the pitch but layer construct in with high temperatures period only, keep temperature bring 80 one 90 up to , make layer receive further debulk the pitch after all.1.4 mechanical impact on pitch roadBecause pitch road surface quality should reflect the mechanical impact on pitch road surface debulk of debulk through rolling finally, so, the selecting type and disposing of debulk machinery seems particularly important. Dark- expressway two bid section (13.4km ) pitch concrete road surface project Kui, construct by Xinjiang the north new construction of road and brige Limited Company, the layers of structure for 6cm thick grains of type grains of grains of type bituminous concrete of the type ten 4cm in the +5cm, the lower floor is the cement stability gravel storey. Each constructed to begin since April of 2000 by the end of September of the same age. Pitch by day work N eight P-1600 for dose rein in 1800 types mix and stir , paver of mixing and stir etc. mixture. According to the regional climate situation of known construction , and mix and stir the productivity of the equipment , paver, transporting the distance and transportation situation, the characteristic of the mixture, pave the thickness, pave layers of location ,etc. , select and make up to the mechanical pattern. Namely use two CC2l a pair of steel and a round of vibration road roller while pressing for the first time , press quietly twice at the speed of 3-5km; When is it press to replying, adopt two CC21 pairs of steel rounds of vibration road roller still, vibration at the speed of 4-5km/11 roll four, dispose the tire road roller of a Model YL16 at the same time, roll twice at the speed of 4-5km/h; After all when pressing, adopt one 2Y8/10 pairs of steel rounds of vibration road roller, at the speed of 3-4km/h quiet to press and accept mere twice. Make from the machinery of the above up and analyse that can be drawn , the having direct relations all over the speed that is counted , rolling with rolling of debulk on the road surface . As thickness , environmental temperature , effective debulk time of paving being when constructing within the person who allow, the ones that rolled would play a decisive role to the debulk of the road surface all over the speed that is counted with rolling.Can know according to experience. The rolls and only fix through testing section all over countinging of pitch road surface, and should also be in the type of the road roller, solidity of pressing, shake frequently under the situation confirmed of valid debulk time of the amplitude , mixture, could get . Can select through conclusion totest section to debulk speed at the same time. By result of the test analyse can know , while rolling all over counting the samly , roll slow than roll speed get high solidity of pigeonholing soon, but it is only higher to press the solidity 0.4-0.8, there is no actual use value, while replying and press and press after all, should try one' s best to choose the high speed of rolling , in order to improve and press the mechanical homework efficiency of the way, reduce its quantity allocated1.5 pitch concrete glueand form analysis and research VFA (pitch consumption) of strength and pitch kind to solve pitch concrete glued and marries the strength problem. Because Marshall's test method has not already accorded with the actual conditions(because the concrete road surface of pitch has been pressed gently by the automobile tire on the real highway, Marshall test hit real number of times whether two sides each hit 75 times, if increase and hit the real number of times at the same time, aggregate break up and break to pieces, but gentle to press and increase aggregate have broken situation take place even quiet year again), so we must solve with other theory pitch concrete oilstone of as with glueing reason of envelope come and explain pitch concrete oil film thickness of as problem we (oilstone than) problem, we spread certain paste to paste while glueing envelopes, with the increase of the pressure, the surplus paste is crowded out, the tighter the envelope mouth is glued, there is the relation between certain pressure and thickness of the paste, the bigger the pressure is, the thinner the thickness of the paste is, it is the bigger to glue the strength of forming. The thickness of oil film of concrete of pitch is the same too, the greater the pressure of rolling the equipment (the tire) adopted when we construct is, keep high temperature for the first time, oil film thickness thin, pitch concrete that form it glues to be heavy to marry strength, this is that the American engineer JOHN.L.MCRAE gentleman's GTM machine rotates the gentle theory of pressing, this GTM testing machine has well solved the equipment (the pressure of the tire) of rolling, rolls the relation that temperature compares with oilstone (the thickness of the oil film). Seeing that of our country large-scale car amount tire pressure up to 1.0 Mpa more than already, propose and use GTM testing machine go on and rotate with 1.0 pressure of Mpa gentle to pigeonhole, temperature130 ∽ 135 when testing, after being steady in order to design the amount of oil used with the oil amount. The on-the-spot construction technological requirement is replied and pigeonholes the temperature after finishing to control above 130 degrees, press and adopt the large tonnage tire road roller for the first time (pressure of tires is more than of 1.0 Mpas).The kind of the pitch and ore material glue the strength of forming influencing the pitch concrete to the seizing of the pitch directly in addition, so the good modified pitch with good resisting splitting at the time of the low temperature at the same time of high-temperature stability has appeared at home, and should deal with the acid and neutral hard quality ore material , improve the seizing, generally adopt and catch the lime wash and is washed or mixed and adds the quick lime powder or low grade cement.2 Pitch preventative maintenance and machinery of concrete road surface2.1 The characteristic of concrete road surface of original sin and type of damagingPitch because concrete road surface use and glue and form strength better pitch material made and combine the material , therefore gluing the strength of forming while strengthening the ore material greatly , has improved the intensity and stability of the mixture, make to use the quality and durability raise road surface . Pitch concrete road surface have surface level, infiltrate, drive a vehicle advantage comfortable, with low noises, therefore find more and more extensive application. But it is often influenced by respects, such as weather, temperature, driving a vehicle and material, and such reasons of the respect as the road surface structure is designed, will present various disease unavoidably, and the disease has brought harmful influence on driving speed, road surface service life, passenger's comfortableness and traffic safety.Pitch damage of concrete road surface overall to can be divided into two big classes, one is structural damage , including the destruction of a certain part whole or among them of structure of road surface , the ones that made road surface unable tosupport and is scheduled loaded; Another functional damage, it might follow and structural damage take place, but because roughness and resisting the decline in slippery performance,etc. make it not have a function booked again, thus influenced quality of driving a vehicle.Pitch early disease of concrete road surface show as early rut and decay of roughness, suffused with oil and resist slippery decline of performance often at expressway, show as early small crack at ordinary arterial highway, detailed material lose cause undisguised, polishes, , the host is lost, surface disease that the road surface infiltrates. That the pitch wears out. If disease the can deal with but develop as one pleases in early days, must lead to the fact surface to be loose further, or cause serious deformation disease, such as peeling off and rut of depth of lower floor. Because of infiltrating, then cause structural damage, such as whole trough, thus must adopt the repairing method to carry on road surface maintenance. So seek one swift helping, cost rational settlement pitch concrete road surface early applicable technology of disease to maintain to be solved problem urgently in the work2.2 Important meaning of preventative maintenanceAround the relation that is built and maintaining, maintaining and preventing, with the constant perfection of the road network, only keep good road surface serviceability for a long time, the huge investment of road construction could give full play to its investment benefit , keep road surface good technological state must have one maintaining and support system come guarantee powerful for a long time, come from this meaning and say , maintain a kind of continuation that is road construction in fact. In the road surface maintains the relation with maintenance, People always get used to it after the road surface begins to be damaged for a long time , just remembers that will carry on maintenance to it, Carry on preventative meaning of maintenance know enough often under being also in good state to road surface. Preventative maintenance is a kind of periodic pressure maintenance measure in fact, it does not consider whether there is a certain damage on the road surface, Preventative maintenance best to implement opportunity should to in good state still in road surface, or go on only at the time of some disease omen .Though preventative maintenance needs to invest some expenses, it is a kind of expenses- benefit than very good maintenance measure. American department mentions in the road surface solution , what the American road industry was once passed to different grades of hundreds of thousands kilometers is followed, find that the serviceability and life-span of these roads have a common change characteristic : A road with qualified quality, performance drops by 40% within service life 75%, called preventative maintenance stage this stage. Such as be unable to in time maintenance, in 12% service life in the time, performance drops by 40% again afterwards, cause and maintain cost increase by a large margin , call that and correct maintenance stage this stages. Count and draw and invest through investigation 1 preventative maintenance fund can economize 3- l0 yuan correct maintenance conclusion of fund each time. U.S.A. SHRP plan one important achievement point out preventative maintenance delay road surface serviceability worsen the speed, lengthen its service life and economize the important meaning of expenses of life cycle.Correct serviceability that implement preventative maintenance and can keep the road surface good , lengthen life cycle of road surface , reduce life cycle expenses and economize and maintain the fund. Plan and estimate according to SHRP , go on preventative maintenance of 3-4 can lengthen 10- 1 years such as service life within life cycle of whole road surface, economize and maintain 45-50% of expenses, these foreign experience of benefitting is worth we drew lessons from . Need emphasize , implement to one- two road preventative maintenance can not give full play to his potential benefit and function only, put it preventative maintenance in network of highways support height of the system pay only, could fully embody its important strategic meaning and function .2.3 Choose suitable preventative maintenance machineryCarry on maintenance promptly when the road surface presents disease omen , make it not happen or continue developing, expanding , influence the stability of the basic unit, should carry on preventative maintenance. Preventative maintenance capital equipment have and irritate and sew machinery, road surface part mend homework machinery, heavy area surface punish machinery, usually.The pressure type irritates the sewing machine: Adopt artificial way to irritate and sew the homework, though can prevent the infiltration of the sub-surface of rainwater , alleviate the development with further crack, but because the sealed material is not irritated deeply enough, it is very difficult to reach the lasting result. Adopt pressure type irritate person who sew can irritate deep layer to reach the crack sealed material, irritate and sew better result , can lengthen service life of road surface , raise and go the security and comfortableness of the vehicle.Irritate and sew homework want and carry on clear to go on and irritate and sew after sewing first generally, greater than 3 crack of mm need and slot the homework generally. Irritate the heating that the sewing machine should be furnished with the control device of pressure, sealed material mainly or keep the device warm, for prevent spray gun hose from stop up and should take corresponding heating, keep measure warm also. The main characteristic of the pulling type is: Heat storehouse volume 470L, relatively more complete function havesuitable for irritating and sewing the homework by a large scale. Pair set up yuans of hand person who push away hot to irritate heating storehouse of person who sew volume 40 L, small easy to operate using flexible, low fabrication cost company, can look at according to work load feeling worthy of and heat cauldron again separately, suitable for hot to caulk the irritating and sewing the homework of material mainly; Have function cold to irritate person who sew without heating, use polymer modify water quality caulk the material mainly. If department pitch cold to irritate and sew material to modify emulsification, as emulsification after the solidification pitch, the modified pitch and crack of high polymer are glued and formed closely, can guarantee that there is good strength of seizing to irritate and sew the material and crack . Because cold to irritate and sew simple, easy to use craft, road surface give person who defend maintenance have wide prospects in pitch.Mend the hole machine in spraying type: Person who spray pitch road surface mend technology one high-efficient mending road surface hole maintenance technology of pool fast, cardinal principle to utilize way of spaying with high presure , mix emulsification pitch that heat already through nozzle with conveyer belt dept. oforthopedics come to convey, spray the mixture to the hole pool of road surface evenly through the compressed air at a high speed, because passing through function reaches and glues the result formed closely knitly. Because craft simple, need and go on and roll again, mend hole short activity duration, can open traffic quickly.Hope that you remember my result every day. Car chassis (or pulling type); Pitch pot of emulsification and heating and keep the device warm, sending the pipeline; The aggregate stores the storehouse and conveyer belt; The cleaner stores the pot; Liquor pressure drive; Air compressor machine and nozzlemake up . In pool go on and clear up, after repairing, attenbant need and know one nozzle (operate button at nozzle handle) can finish the hole pool of road surface mend the homework only to hole. Should pay attention to controlling the quality of the good aggregate and grading in using; Choose the broken milk tempo of the good emulsification pitch ; Grasp the spraying amount and so as to ensure roughness of road surface after mending, Mend machinery in hot regeneration of road surface : For economize valuable way spend material, reduce and mill old material pollution of the environment these come down to plane, many place popularize old way spend regeneration of material, pitch hot recycled craft because with cold to mill- factory mix recycled craft compare on the spot among them in a more cost-effective manner, reduce old material freight and factory mix regeneration need use continuous type to mix and stir the reasons, such as equipment. Generally, the maintenance of the expressway is widely used with maintaining in JiangsuProvince. Reach materials that company offer according to Great Britain, " repair the roads king " its mend method compare with traditional method, it can save 5/6 to mend time, personnel save 1/2 for homework, the old way totally utilizes with the material, new pitch mixture consumption can save 1/2 .Hot recycled key part of equipment to heat board mainly on the spot, it want offer high-efficient heat energy of radiating, heat and should short time to old road surface have, and reach certain depth; Can't be overheated, make the pitch wear out , lose the recycled meaning. Great Britain reach company repair the roads king heat board take interval heating way, can one is penetrated to the road surface deep layer, and road surface top layer pitch wear out again and hotly, well solve this problem . Inaddition according to mend area of uniform size, heat board it's better to have the sub-zone function.The rare thick liquid seals one layer of pitch rare thick liquid of emulsification with modifying and seals one layer of pavers: Rare thick liquid seal layers of technology to new, old wear out, crack, smooth loose of road surface, hole trough. Disease can play prevent and function of maintenance, make road surface waterproof, resist slippery, levels, wear-resisting performance is raised rapidly. In recent years, because rare thick liquid seal layers of standardization that construct, standardize, construction quality raise and reducing of cost, rare thick liquid seal layer apply common road and expressway maintained and had in early days extensively already.Modify emulsification pitch rare thick liquid seal layer modify emulsification pitch with roll and break to pieces by water quality high polymer intensive material, mineral packing, water and surface that additive make up punish layer one, can pave the thin layer , solidify fast, can open traffic in an hour after constructing in characteristic, because modify the pitch rare thick liquid of emulsification seal one layer of solidification time faster than the ordinary rare thick liquid, modify emulsification pitch rare thick liquid seal layer can seal than traditional rare thick liquid layer thick. Used in the punishment of constructing disease, such as repairing, chap, rut, etc. of road surface mainly, can be used for sealing and improving resisting slippery punishment of road surface. But modify the pitch rare thick liquid of emulsification is the same as other thin layers are punished, only have highway section with steady structure now suitably, must construct after mending strongly when curved sinking value is not enough. Guarantee modify emulsification pitch there aren't the thick liquid not rares. Modify emulsification pitch rare thick liquid material viscidity heavy, pave layer relatively thick, generally speaking, modify emulsification pitch raise than the emulsification pitch viscidity not modifying by 30-50%, result in and make obstruction heavy thick liquid, the speed slows down. Demand and modify emulsification pitch rare thick liquid seal layers of equipment device corresponding to strengthen power store to make thick liquid, cloth fast, mobility fine, cloth speed pave range that the thickness regulate heavy, in order to meet modifying the constructionrequest for sealing layer of rare thick liquid of pitch of emulsification.The pitch road surface maintains machinery and cares the car synthetically, cares the car etc. multi-functionally, have given play to one's own characteristics in the maintenance of the superhighway. As the constant increase,, especially the expressway of the superhighway increase, and the constant innovation on maintenance work craft and material , the mechanical manufacturer to maintaining , including the respects, such as designing, making, after-sale service. Put forward higher and higher request. Too should maintain mechanical applying unit from maintenance, quality of attenbant of equipment, maintenance exertion of material,etc. pays enough attention, it is in many aspects to accomplish, multi-disciplinary close cooperation, could promote the preventative maintenance mechanized development of the highway to the maximum extent .3 pitch concrete road surface in constructing1.one of precautions infiltrate, design and grade kind pitch concrete match ratio very in theory in constructing, in not butting if can't construct it guarantee by pitch concrete homogeneity(include and grade and last homogeneity that shut pitch , homogeneity that pave, roll homogeneity of shaping), pitch concrete road surface equally will produce infiltrate, purt thick liquid, rut, suffused with oil,etc. destroy the phenomenon in early days. Stone fit expressway pitch concrete finish adopt many broken stone pitch concrete (SAC) make finish structure, SAC structure does not infiltrate theoretically, and have good resisting the slipping and temperature stability, can meet and construct TD of depth > request for 0.7mm, why is it very good in some paragraphs on the line of Ann of stone, some paragraph very serious to destroy phenomenon in early days, main reason to guarantee pitch concrete homogeneity of road surface and pigeonhole solidity, pursue the roughness to cause excessivly. Guarantee pitch homogeneity of concrete and pigeonhole solidity key problem very in constructing. Sand celebrate academician Lin in " expressway pitch road surface destroy phenomenon with predict " book chapter ten describe to pitch concrete importance of homogeneity specially " in early days. Only brief here to sum up the。

桥梁工程本科毕业设计外文翻译---混凝土桥梁的结构形式

本科毕业设计外文翻译混凝土桥梁的结构形式院（系、部）名称：专业名称：学生姓名：学生学号：指导教师：The Structure of Concrete BridgePre-stressed concrete has proved to be technically advantageous, economically competitive, and esthetically superior bridges, from very short span structures using standard components to cable-stayed girders and continuous box girders with clear spans of nearly 100aft .Nearly all concrete bridges, even those of relatively short span, are now pre-stressed. Pre-casting, cast-in-place construction, or a combination of the two methods may be used .Both pre-tensioning and post tensioning are employed, often on the same project.In the United States, highway bridges generally must-meet loading ,design ,and construction requirements of the AASHTO Specification .Design requirements for pedestrian crossings and bridges serving other purposes may be established by local or regional codes and specifications .ACI Code provisions are often incorporated by reference .Bridges spans to about 100ft often consist of pre-cast integral-deck units ,which offer low initial cost ,minimum ,maintenance ,and fast easy construction ,with minimum traffic interruption .Such girders are generally pre-tensioned .The units are placed side by side ,and are often post-tensioned laterally at intermediate diaphragm locations ,after which shear keys between adjacent units are filled with non-shrinking mortar .For highway spans ,an asphalt wearing surface may be applied directly to the top of the pre-cast concrete .In some cases ,a cast-in-place slab is placed to provide composite action .The voided slabs are commonly available in depths from 15 to 21 in .and widths of 3 to 4 ft .For a standard highway HS20 loading, they are suitable for spans to about 50 ft, Standard channel sections are available in depths from 21 to 35 in a variety of widths, and are used for spans between about 20 and 60 ft .The hollow box beams-and single-tee girders are intended for longer spans up to about 100 ft.For medium-span highway bridges ,to about 120 ft ,AASHTO standard I beams are generally used .They are intended for use with a composite cast-in-place roadway slab .Such girders often combine pre-tensioning of the pre-cast member with post-tensioning of the composite beam after the deck is placed .In an effort to obtain improved economy ,some states have adopted more refined designs ,such as the State of Washington standard girders.The specially designed pre-cast girders may be used to carry a monorail transit system .The finished guide way of Walt Disney World Monorail features a series of segments, each consisting of six simply supported pre-tensioned beams ,together to from a continuous structure .Typical spans are 100 to 110 ft . Approximately half of the 337 beams used have some combination of vertical and horizontal curvatures and variable super elevation .Allbeams are hollow, a feature achieved by inserting a styro-foam void in the curved beams and by a moving mandrel in straight beam production.Pre-cast girders may not be used for spans much in excess of 120 ft because of the problems of transporting and erecting large, heavy units.On the other hand ,there is a clear trend toward the use of longer spans for bridges .For elevated urban expressways ,long spans facilitate access and minimize obstruction to activities below .Concern for environmental damage has led to the choice of long spans for continuous viaducts . For river crossings, intermediate piers may be impossible because of requirements of navigational clearance.In typical construction of this type, piers are cast-in-place, often using the slip-forming technique .A “hammerhead” section of box girder is often cast at the top of the pier, and construction proceeds in each direction by the balanced cantilever method. Finally, after the closing cast-in-place joint is made at mid-span, the structure is further post-tensioned for full continuity .Shear keys may be used on the vertical faces between segments, and pre-cast are glued with epoxy resin.The imaginative engineering demonstrated by many special techniques has extended the range of concrete construction for bridges far beyond anything that could be conceived just a few years ago .In the United States, twin curved cast-in –place segmental box girders have recently been completed for of span of 310 ft over the Eel River in northern California .Preliminary design has been completed for twin continuous box girders consisting of central 550 ft spans flanked by 390 ft side spans.Another form of pre-stressed concrete bridge well suited to long spans is the cable-stayed box girder .A notable example is the Chaco-Corrientes Bridge in Argentina .The bridges main span of 804 ft is supported by two A-frame towers, with cable stays stretching from tower tops to points along the deck .The deck itself consists of two parallel box girders made of pre-cast sections erected using the cantilever method .The tensioned cables not only provide a vertical reaction component to support the deck ,but also introduce horizontal compression to the box girders ,adding to the post-tensioning force in those members .Stress-ribbon Bridge pioneered many years ago by the German engineer Ulrich Finsterwalder. The stress-ribbon bridge carries a pipeline and pedestrians over the Rhine River with a span of 446 ft .The superstructure erection sequence was to (a) erect two pairs of cables, (b) place pre-cast slabs forming a sidewalk deck and a U under each of the sets of cables, and (c) cast-in-place concrete within the two Us. The pipeline is placed atop supports at railing height, off to one side, which greatly increases the wind speed of the structure.It is appropriate in discussing bridge forms to mention structural esthetics .The time ispast when structures could be designed on the basis of minimum cost and technical advantages alone .Bridge structures in particular are exposed for all to see .To produce a structure that is visually offensive ,as has occurred all too often in the past, is an act professional irresponsibility .Particularly for major spans ,but also for more ordinary structures ,architectural advice should be sought early in conceptual stage of the design process.混凝土梁桥的结构形式事实证明，预应力混凝土结构是在技术上先进、经济上有竞争力、符合审美学的一种先进技术。

外文翻译道路工程

SCAFFOLDS FAILURES CAUSED BY VEHICLE STRIKES DURING12CONSTRUCTION OF NEW VIADUCT OVER A-18 MOTORWAY IN POLAND34567Zbigniew “Zee” Manko8Professor of Civil and Structural Engineering, Bridge Division, Institute of Civil Engineering 9Wroclaw University of Technology, Wybrzeze Wyspianskiego No. 27, 50-370 Wroclaw, Poland 10Tel./fax (+48) 71 352-92-74 zbigniew.manko@wp.pl11(Corresponding author)12131415Word count: text (3122) + 7 figures (7 × 250 = 1750) + 0 tables (0 × 250 = 0) = 487216Submission date: June 5, 2009.171819202122232425262728293031323334353637383940414243444546Abstract: The paper is presented cases of failures of steel scaffolds damaged by vehicle strikes 12during the construction of new viaducts over the upgraded A-18 motorway in Poland. After3several vehicle strikes into the scaffold structures their damaged components were no longer4serviceable (considering the safety of the construction works being carried out). This put the5contractor to additional expenses connected with the replacement of the damaged scaffold. The 6causes and consequences of the failures are given and the necessary solutions adopted in the7considered cases – whereby the traffic situation significantly improved – are described.8Moreover, it is proposed to increase the minimum vertical clearance required during the building 9or repairs of bridge structures.101112Keywords: Scaffold Failure, Vehicle Strike, Damaged component, New Object, Viaduct13Construction, Motorway A-18.141516171819202122232425262728293031323334353637383940414243444546INTRODUCTION12Formerly in Poland, a little attention was paid to the bridge-specific design and erection of3scaffolds, which was the cause of many serious failures (1), (2), (3), (4), (5), (6), (7), (8). Today bridge scaffolds are classified as engineering structures and require the detailed design, including 45all aspects, which may occur from their erection, through the full loading of the spans during6concreting, to their dismantling, in accordance with the current guidelines (PN-M-47900-3 (9),7PN-M-47900-1 (10), and PN-M-48090 (11). When new bridge structures are built over transport 8obstacles, the continuity of vehicle traffic must be ensured, particularly on national roads, which9carry traffic through the whole bridge construction period (12), (13), (14).Unfortunately, the heavy trucks (e.g. TIR lorries) and tractor-trailer units carrying various1011machines and equipment drive through the clearance gates shaped in the scaffolds using during 12building of motorway bridge structures most often strike at the new scaffold components already built. It refers these both as well as the trucks of permissible and over normative dimensions1314which mainly conducting to serious damages of scaffolds or their structural elements.15Using as example motorway viaducts WD-14 and WD-12 built over national road A-18 16(which is being upgraded), the failures of the scaffolds erected to build on site the concrete17objects are described and their causes are explained. The cases considered here and the ones18presented previously (1), (2), (7), (13), (14), (15), (16) clearly show the need to modify andupdate the guidelines for erecting scaffolds for the building of road bridge structures. This1920applies particularly to the minimum headroom (vertical clearance) since the current standard one 21is inadequate. The above considerations should be taken into account in the designs of bridgestructures.222324DESCRIPTION OF OLD AND NEW VIADUCT WD-1425The old reinforced concrete viaduct (built in 1934) consisted of two spans having an effective26length l e = 14.00 + 14.00 = 28.00 m. The span overall width was 6.76 m, load class D (200 kN) 27according to the PN-85/S-10030 (17), the vertical clearance – 4.53 m. The viaduct was situated 28at a skew of 45 to the road’s longitudinal axis. Because of the viaduct’s bad technical condition,29it was not worthwhile to upgrade it and so it was demolished (Figure 1).30The new viaduct is located at the 0+179.79 km of Cisowa – Jedrzychowiczki (Henrykow)31local road No. 4918009 being upgraded. The viaduct makes possible the safe crossing of national 32road No. 18 at its 13+634.37 km. The designed viaduct WD-14 is located in the place of the olddemolished one (Figure 1).3334The new reinforced concrete viaduct with a trapezoidal single-girder cross section and a35continuous-beam static scheme has four spans with an effective length l e = 18.00 + 27.00 + 27.00 36+ 18.00 = 90.00 m. The axes of the supports are parallel to the national road and with the37viaduct’s longitudinal axis form an angle of 44.99’. The middle spans cross the two carriageways 38of the national road. There are technological strips and the local road embankment slopes under the extreme spans. The main girder is 1.50 m high and 2.70 m and 3.20 m wide respectively at3940the bottom and top (at the level of the cantilevers’ bottom). The cantilevers’ width varies from 410.21 to 0.40 m and their outreach is 1.90 m. The overall width of the load-carrying structure is7.00 m. The overall width of the viaduct is B = 7.70 m, including the roadway between the curbs4243(6.10 m) and sidewalks with the rigid barriers (2 × 0.80 m). The viaduct’s total surface area44bounded by the deck edges is A = 7.70 × 92.10 = 709.17 m2. The local road’s technical class is L(4), (5). The target traffic clearance under the viaduct is H c = 4.70 m. The viaduct traffic loading4546is as for class B (400 kN) according to the Polish Bridge Load Standard PN-85/S-10030 (17).The viaduct load-carrying structure was made of reinforced concrete and it reposes on 1 supports (abutments) via elastomer bearings (the middle support and the span structures are 2 joined together monolithically). The grade of the load-carrying structure concrete is B35 and the 3 steel grade – 18G2-b.4 The intermediate supports (piers) have the form of oval columns 2.40 m wide and 1.00 m5 thick and they are founded directly on a continuous footing 3.60 × 7.20 m in plan and 1.40 m6 thick. There is B35 and B30 class concrete in respectively the columns and the footing. The7 massive abutments are sunk in the embankment and founded directly on a continuous footing8 4.50 × 1.20 m in cross section. The wing walls are suspended from the abutment body and joined9 with the continuous footing.1011 USE OF SCAFFOLDS FOR CONSTRUCTION OF VIADUCT ON A-18 MOTORWAY 12 Proper working designs of the span scaffolds for the WD-14 – WD-19 viaducts were created. For 13 the already built supports (18) the necessary scaffold and formwork to be used under viaduct 14 spans was designed (19), (20), (21), (22), (23), (24), (25), (26). The grade lines for the new 15 viaducts were taken from their design documentation (18). The elevation of the pavement16 reinforced concrete slabs under the scaffolds was determined based on the levels obtained from 17 geodetic surveys carried out by the building contractor (Figure 2).18 The RöRo scaffolds of type L (20) erected outside the road clearance – on each side two 19 towers in the axis of the load-carrying structure and in addition, more widely spaced scaffolds 20 under the spans’ cantilevers (Figure 3) – were to be used for concreting the spans of the viaduct.21 The spans situated directly above the road clearance were supported by heavy scaffolds 22 H20 type on which double-T (20) steel girders were put up (Figure 2).23 The following scaffold components were used:24 ∙ steel beams – HE-B 160, HE-B 360, HE-B 300, 220M HE; 25 ∙ frame supports – RöRo L supports;26 ∙ grillage supports – HUNNEBECK H20; 27 ∙ pipe bracings – O48.3 × 4.05/S 235;28FIGURE 1 Cross sections of viaduct WD-14 and WD-12 (dimensions for the latter are given in brackets).1various connections, i.e. steel couplers and clamps, etc., conforming to the EngelhardRöRo2standard (16), (20).3Moreover, a template of constant-cross-section formwork (Figure 2) with a single girder 4trapezoidal in cross section was designed and made (21), (22).56DAMAGE TO SCAFFOLDS DURING THEIR ERECTION7General Remarks8During the construction of viaduct WD-14 the structural components of the scaffold near the9drive-through clearance were damaged twice due to the too small standard headroom (insuffi-10cient for the proper location of scaffolds for the construction of bridge spans). The standard11headroom is H = 4.20 m and in many cases, it no longer meets the current service conditions.12Therefore, after the first vehicle struck at the girders of the scaffold situated immediately 13above the road clearance (conforming to the technical documentation approved by the motorway 14supervision authority) the headroom was increased by the available reserve (by redesigning and 15rebuilding the load-bearing structure of the scaffold). This, however, did not help much sincesoon another vehicle hit the lower part of the scaffold located directly above the drive-through.1617After the second vehicle strike, the designers of the scaffold together with the viaduct builder had 18to increase the vertical clearance. They decided that the minimum safe vertical clearance in thisFIGURE 2 Cross section of viaduct WD-14 with structure of scaffold put up above road clearance.case should be H1 = 4.30 1m. At this clearance no 2more vehicle strikes3occurred. The scaffolds 4and the new vertical5clearance were tried out 6on another viaduct, i.e. 7WD-19. The vehicle,8which previously9damaged the scaffold of 10WD-14 this time, drove 11through.1213Description of14Accidents Involving15Vehicles Striking16Scaffold Components 17The first collision18occurred on 2919September 2005. A TIR 20lorry (semi trailer height 21over 4.20 m) from22Ukraine struck the23scaffold and as a result 24got stuck under the span, 25seriously damaging the 26structural components of 27the scaffold.28A few days later29on 3 October 2005 in the 30morning hours, a tractor-31trailer unit transporting 32an excavator struck the 33scaffold components34situated immediately35above the clearance of 36viaduct WD-14. As a37result all the girders were 38knocked off and fell39down onto the roadway 40(Figure 4). Another41strike of this vehicle into 42the scaffold of viaduct 43WD-12 caused two44girders to turn (Figure 5).45The transported46excavator, as the police 47STEPISTEPISTEPI(c)(d)(b)FIGURE3ArrangementofEngelhardRöRoscaffoldsforviaductWD-14:(a)topview,(b)longitudinalsectionA–A(verticalclearanceH=4.2m),(c)longitudinalsectionA–A(verticalclearance4.24m),and(d)longitudinalsectionA–A(verticalclearance4.33m).findings show, probably was stolen from another building site, which explains the driver’s 1 unusual determination to ram all the obstacles on his way. Luckily, at this time, the vehicle 2 traffic on the road was relatively light, there were no construction workers on the scaffolds, no 3 concreting work was being conducted, and so there were no casualties.45 Change of Vertical Clearance in Viaduct WD-146 Because of the relatively low elevation of the spans of viaduct WD-14 over the A-18 motorway,7 nobody expected that the standard vertical clearance of 4.20 m could be insufficient. In the case8 of the other viaduct over the same road, there were substantial reserves in height owing to the9 grade line adopted in the design. Therefore, quite simply and naturally the actual vertical 10 clearances under the scaffolds were much larger than the required minimum of 4.20 m. 11(a)(b)FIGURE 4 View on the damaged scaffold supports in viaduct WD-14 after vehicle struck main girders located above drive-through clearance: (a) view from roadway, (b) side view.(a)(b)FIGURE 5 View of viaduct WD-12 scaffold after vehicle strike: (a) damaged and turned steel girders of scaffold (two girders on Wroclaw side were turned), (b) collapsed reinforcement of span load-bearing structure before planned concreting.In the case of viaduct WD-14, two vehicle strikes into steel girders located above the 1 drive-through clearance occurred whereby the contractor and the designers had to redesign the 2 scaffold structure several times.3 The first alteration in the height of the drive-through clearance under the load-bearing4 girders of the scaffold was made by replacing the HE 360-B girders (10 units) with 16 girders of5 the HE 300-B type because of which the spacing of the main H20 girders decreased from 9.35 m6 to 8.35 m. In this way, a vertical clearance of 4.26 m was obtained. It was thought that there7 would be no more collisions (Figure 3c).8 After the second vehicle strike into the increased (from 4.20 m to 4.26 m) vertical9 clearance it became necessary for safety reasons to redesign the height of the drive-through gate. 10 A detailed analysis of the causes of the damage to the scaffold showed that replacing the HE-B 11 300 girders with shorter ones was out of the question because of the insufficient load-capacity of 12 any shorter girders. It was found, however, that it was possible to reduce the height of the13 formwork trusses situated immediately above the clearance from 0.10 m to 0.06 m. In addition, 14 because of the roadway cross fall (2%) the whole drive-through gate was moved to the edge of 15 the roadway, towards the lowest road grade line whereby a few more reserve centimeters were 16 obtained (Figure 6). In this way a vertical clearance of 4.33 m was obtained at the lowest point of 17 the road (4.36 m at the edge of the clearance), i.e. by 0.13 m larger than the standard clearance of 18 4.20 m and by 0.07 m larger than the other clearance of 4.26 m (Figure 3d). The new drive-19 through height of 4.33 m ensured safe work on the viaduct until its completion. 2021 CONCLUSIONS22 Considering the two cases of scaffold failures on viaducts built on the upgraded A-18 motorway, 23 caused by vehicle strikes into scaffold girders situated above the clearance, in the nearest future 24 the much out-of-date guidelines on the minimum vertical road clearance (4.20 m) required 25 during the construction of bridge structures should be amended. Based on the authors’26 experience in the design, site supervision and use of scaffolds it can be stated that the vertical 27 clearance should not be smaller than 4.30 m instead 4.20 m.28(a) (b)FIGURE 6 Side view of encased scaffold of viaduct WD-14 prior to concreting load-carrying structure after two vehicle strikes into girders located above clearance: (a) H20 scaffolds erected under formwork, (b) drive-through clearance outline shifted to edge of roadway.Until the proper amendments are 1 adopted half measures must be used and 2 in the cases where the height of the drive-3 through clearance cannot be increased 4 above 4.20 m, unbreachable solid drive-5 through gates and warning systems, such 6 as audible and visual signaling devices, 7 warning drivers early that their vehicles 8 exceed the height of the drive-through 9 gate located in front of the road structure 10 should be erected. It should be added that 11 if all the above possibilities have been 12 exhausted, one should contact the road 13 services, which must screen vehicles and 14 direct the ones with excessive height to 15 previously prepared diversions.16 Regardless of the increased road 17 height clearance and additional18 protections (Figure 7), one should always 19 take into account the fact that because of 20 some irresponsible road users there is a 21 real possibility that the scaffold will be 22 damaged.2324 References25 (1) Flaga, K. Technical-Construction Expert Opinion on Causes of Collapse of Viaduct 26 on Skoczow – Cieszyn National Road S-1 in Ogrodzona. Typescript , Cracow, Poland, Aug., 27 2003 (in Polish).28 (2) Flaga, K. Reflections on Collapse of Viaduct in Ogrodzona. 22nd Scientific-Technical 29 Conference on Structural Failures, Prevention–Diagnostics–Repairs–Reconstruction , Szczecin –30 Miedzyzdroje, Poland, May 17–20, 2005, pp. 53–66 (in Polish).31 (3) Furtak, K., and W. Wolowicki. Bridge Scaffolds . Wydawnictwa Komunikacji i 32 Lacznosci (WKiL), Warsaw, Poland 2005 (in Polish).33 (4) Ministry Technical Requirements. Minister of Transport and Marine Economy Order 34 of 2 March 1999 concerning Technical Requirements which Public Roads and their Location 35 Should Meet , Law Gazette (Dz.U.), 1999, No. 43, item 430 (in Polish).36 (5) Ministry Technical Requirements. Minister of Transport and Marine Economy Order 37 of 30 May 2000 concerning Technical Requirements which Road Structures and their Location 38 Should Meet , Law Gazette (Dz.U.), 2000, No. 63, item 735 (in Polish).39 (6) Rowinski, L. Working and Load-Bearing Scaffolds. Polskie Centrum Budownictwa 40 (PCB), Warsaw, Poland 2001 (in Polish).41 (7) Rymsza, J. On Causes of Collapse during Construction of Viaduct over Dual42 Carriageway S-1 on Skoczow – Cieszyn Section. Inzynieria i Budownictwo , Vol. LX, No. 3, 43 2004, pp. 140–143 (in Polish).44 (8) Wolf, M. Bridge Scaffolds and Formworks. Wydawnictwa Komunikacji i Lacznosci 45 (WKiL), Warsaw, Poland 1964 (in Polish).46 (9) PN-M-47900-3. Standing Working Metal Scaffold. Frame Scaffolds. 1996 (in Polish).47FIGURE 7 View of beam marking height ofclearance (3.70 m) before entry into road section where scaffolds were being erected andreinforcement installed prior to concreting spans (vertical clearance for all viaduct being built was 4.20 m and was larger than clearance height on warning gate where there was exit leading to another road).1(10) PN-M-47900-1. Standing Working Metal Scaffold. Definition. Division and Main2Parameters. 1996 (in Polish).3(11) PN-M-48090. Steel Scaffolds Made from Folding Components for Bridge4Construction. 1996(in Polish).5(12) Glomb, J. Technology of Building Concrete Bridges. Wydawnictwa Komunikacji i 6Lacznosci (WKiL), Warsaw, Poland 1982 (in Polish).7(13) Holowaty, J. Case of Damage to Bridge Scaffold Support Caused by Vehicle Strike 8during Concreting of Spans. 21st Scientific-Technical Conference on Structural Failures,Prevention–Diagnostics–Repairs–Reconstruction, Szczecin – Miedzyzdroje, Poland, May 20–91023, 2003, pp. 567–572 (in Polish).11(14) Holowaty, J. Scaffold Structures for Building Overpasses Providing Access to12Bridge Crossing over Regalica River in Szczecin. IV All-Polish Bridge Engineers Conference on 13Bridge Structures and Equipments, Wisla, Poland, Oct. 12–14, 2005, pp. 63–70 (in Polish).14(15) Barzykowski, W., J. Derecki, A. Feder, L. Jaczewski, A. Jarominiak, and M.Pierozynski. Bridge Construction Mechanization. Wydawnictwa Komunikacji i Lacznosci1516(WKiL), Warsaw, Poland 1971 (in Polish).17(16) Construction Equipment Bridge Formworks. Magazyn Autostrady, Special edition,Vol. 37, 2006 (in Polish).1819(17) PN-85/S-10030. Bridge Structures. Loads. The Polish Bridge Load Standard. 1985 20(in Polish).(18) Working Designs Modernization of National Road No. 18 along Section: Olszyna2122Interchange – Golnice Interchange, Section 3. Road Structures WD-14, WD-15, WD-16, WD-2317, WD-18, WD-19. TRANSPROJEKT – WARSZAWA Roads & Bridges Design-Research24Office, Warsaw, Poland 2003 (in Polish).25(19) Technical Guide. Scaffolds. Formworks 2005 (in Polish).26(20) Catalogue. EngelhardRöRo L and H20 Types Scaffolds 1998–2008 (in Polish).(21) Kaluzinski D., and Z. Manko. Designs of Viaducts WD-14 – WD-19. MOSTAR2728Scientific-Research Center for Bridge Construction Development, Wroclaw, Poland 2005 (in29Polish).(22) Kaluzinski, D., and Z. Manko. Designs of Formwork for Viaducts WD-14, WD-15,3031WD-16, WD-17, WD-18, WD-19. MOSTAR Scientific-Research Center for Bridge32Construction Development, Wroclaw, Poland 2005 (in Polish).33(23) Kaluzinski, D., and Z. Manko. EngelhardRöRo Scaffolds. Magazyn Autostrady,34Special Edition, Part I, No. 10, Oct., 2006, pp. 40–48 and Part II, No. 12, Dec., 2006, pp. 84–89 35(in Polish).(24) Kaluzinski, D., and Z. Manko. Damage to Scaffolds during Construction of New3637Viaduct over A-18 Motorway. 23rd Scientific-Technical Conference on Structural Failures,38Prevention–Diagnostics–Repairs–Reconstruction, Szczecin – Miedzyzdroje, Poland, May 23–3926, 2007, pp. 895–902 (in Polish).40(25) Kaluzinski, D. and Z. Manko. Damage to Scaffolds during Construction of New41Viaduct over A-18 Motorway. Magazyn Aurostrady, 2008 (in print) (in Polish).(26) Kaluzinski D., Z. Manko, A. Mordak, and D. Beben. Scaffolds Failures Caused by4243Vehicle Strikes during Construction of New Viaduct over A-18 Motorway. 12th International44Conference and Exhibition on Structural Faults & Repair Extending the Life of Bridges, Concrete +45Composites, Buildings, Masonry + Civil Structures, June 10–12, 2008, Edinburgh, UK, p. 59 (abstract), 46and full paper on CD-ROM.。

本科毕业设计外文文献翻译

（Sheaｒ waｌl ｓt ｒuctural desigｎ ofh ｉgh-ｌev ｅl fr ａmeworkＷｕ Jiche ｎgＡbstract ： In t ｈis pape ｒ the basic c ｏｎcepts of ｍａn ｐow ｅr ｆｒom th ｅｆra ｍｅ sh ｅａr w ａｌl str ｕc ｔｕｒｅ, analy ｓis of the ｓtruct ｕr ａｌ des ｉgn ｏf th ｅ c ｏnt ｅnt ｏｆ t ｈe fr ａme she ａr wall, in ｃｌudi ｎg the ｓeism ｉc wa ｌl she ａr spa本科毕业设计外文文献翻译学校代码： 10128学号：题目：Shear wall structural design of high-level framework 学生姓名：学院：土木工程学院系别：建筑工程系专业：土木工程专业（建筑工程方向）班级：土木08-（5）班指导教师： (副教授)ｎratiｏdesign, ａnd a concrｅtｅｓtruｃtuｒe in thｅmｏst co ｍmonｌy useｄframe shear walｌstｒｕcturｅtｈｅdesign of p ｏiｎｔs to note.Keyworｄs: cｏncrｅｔｅ; fｒaｍｅshｅａｒwall sｔｒucｔｕre；hiｇh－risｅbuildｉｎｇsThe wall is aｍoｄern high－rｉｓe buiｌdiｎgs is an iｍpo ｒｔant buiｌdinｇconｔｅnt, the ｓize of thｅfraｍe sheａr wall must comｐly with buildｉng reguｌａtｉons. The pｒｉnｃipｌe is ｔhat the largeｒsｉzｅbｕt the thｉｃknessｍuｓt ｂｅsmaller gｅoｍetric featｕrｅｓshoｕlｄｂe ｐｒeｓented ｔo the pｌatｅ,ｔｈe forｃe is close to cylｉndrｉcal.Ｔhe waｌl sｈｅar wa ｌl strｕｃｔure ｉs a flaｔcomｐonent. Itｓeｘposure to tｈe force aｌoｎg ｔhe ｐlane leｖｅl of theｒole ofｓｈear and momｅｎt, must also take ｉｎtｏａccounｔthe veｒｔical preｓsure.Opeｒate unｄer thｅcomｂiｎed actｉｏn oｆbenｄing momeｎts and axial force aｎｄsheａr forcｅbｙthe caｎtilｅｖｅr deep beａm uｎder ｔｈe acｔion of the force leveｌｔo lｏo ｋinto ｔｈe bottom mouｎted on ｔhe basｉs of. Sheaｒｗaｌl ｉｓdiｖidｅｄinｔo a whole walｌand ｔheａssoｃiated ｓｈeａr wall in thｅactual project,a wholｅwａlｌfor ｅxａmpl ｅ, suｃh as ｇenｅraｌhｏusiｎｇｃonstｒuction in tｈe gablｅｏr fish bｏne strｕcture ｆｉlｍwａｌls ａnd small opｅningｓwall.Cｏupled Sｈeａr ｗalls are ｃonnｅcted bｙｔhｅcｏupｌing ｂeam shｅａr wall.Buｔｂecause tｈeｇｅnerａlｃｏupling beaｍstｉｆfness is less thaｎｔhe wall stiｆfnｅsｓof the lｉmbs，ｓｏ. Wａlｌliｍb aｌonｅis obviｏus.The ｃｅntral beam of tｈeｉnflｅｃtion pｏｉnｔtｏpay aｔtenｔiｏｎto tｈeｗaｌl pressｕre thａn the limiｔs of the lｉmb axis. Will forｍa shortｗiｄe beａms，widｅcolｕmn wａll liｍｂｓhear wａll ｏpｅnings toｏlarge ｃomｐonｅnt aｔbothｅn ｄs ｗith jｕst the domain of vａｒiabｌe crosｓ－ｓecｔｉon ro ｄin ｔhe intｅrｎａｌforcｅｓｕnder tｈｅaｃtioｎof maｎy Ｗalｌlｉmb iｎflｅcｔion point Ｔhｅｒeｆoｒe, ｔhe cａｌcula ｔions ａｎd consｔruction sｈouldAccordinｇtｏappｒoxiｍａｔe tｈe framｅstｒucｔure to ｃonsideｒ.Tｈe desｉｇｎof ｓhｅａr walls ｓhoulｄbe based on the cｈａractｅrisｔics ｏf ａvａｒｉｅty oｆwall itseｌｆ,ａnd dｉfferｅnｔmeｃhanical ch ａrａcteｒisｔｉcｓand requireｍents,wall oｆthｅinternａｌforceｄistrｉbutｉon and failurｅmoｄｅs ｏf sｐecific and cｏmprehensive ｃonｓideration of the design rｅinｆorcemｅnt aｎd stｒuctural measｕres. Ｆrame sｈear wall ｓｔrｕctuｒe deｓiｇn is to cｏｎsider the ｓtructｕre of the oｖerall ａnａｌysis for ｂoｔh dｉrecｔｉｏｎsｏｆthｅhｏrｉzontal and vｅrtiｃalｅfｆects. Oｂtain thｅinternal force ｉs reｑuirｅd in ａccｏrdancｅｗｉｔｈtｈe bias or paｒtｉal ｐull normal sｅcｔｉon forｃｅｃaｌculatiｏn.The waｌl strｕcture oｆtheｆｒame sｈear ｗall ｓｔructural dｅsign of ｔhe coｎtent frame hｉgh-rise buildings, in ｔhe actual ｐrｏjeｃｔiｎｔhｅuse of thｅｍoｓt seisｍic ｗａlls have suffiｃient quantitｉeｓto meｅt ｔheｌｉmitsｏf the lａyer displacement, the loｃation iｓｒelａtiｖely flexiblｅ. Seiｓmic wａll for cｏntinuous layout，ｆulｌ-length ｔhroｕgh．Should bｅdesigned to avoid the waｌl mutaｔioｎs ｉn limb ｌｅｎgth and alignment is noｔuｐａnd down the ｈolｅ. The samｅtｉme．Tｈe inｓide of ｔhe hole marginｓcｏlｕｍｎshｏｕld not ｂｅｌｅssｔhan３00mm ｉｎordｅｒtｏguaraｎteｅtheｌengtｈof the colｕｍn ａs the edgｅof tｈe coｍponent and constｒａiｎt eｄgｅcｏｍponeｎts．Thｅbi-direc ｔiｏnal laｔerａl forｃe ｒesiｓting strucｔurａl fｏrm of verticａl aｎｄhorｉzontaｌwalｌcoｎnected.Eａｃh ｏｔhｅr as ｔhe ａffiｎiｔｙof the shｅar wall. Ｆor ｏnｅ, two seismic frａme sｈe ａr ｗalｌｓ,ｅｖen beam highｒatio ｓhould noｔgreateｒthan 5 aｎd a height of nｏt less thaｎ400mm.Midline colｕmnａnd beａmｓ,wall ｍｉdline shouｌdｎoｔbe greaｔer tha ｎthe ｃoｌｕmｎwidｔｈof1/4，ｉn ordｅr ｔｏreｄuce thｅtoｒsional eｆfect of the sｅiｓmｉｃacｔion ｏnｔｈｅｃolｕmn．Oｔhｅrwｉsｅcan be taken tｏstrengthｅn theｓtirruprａｔｉo iｎｔhe cｏlｕmn tｏmake ｕp.If thｅshear wａｌl sheａｒsｐａn ｔhａnｔhe ｂig twｏ. Ｅveｎthe beａｍcro ｓs-heｉｇht ratiｏgreateｒthan 2.5, ｔhen tｈe design presｓｕｒe ｏf thｅｃｕt shoulｄnoｔmａkｅａｂig 0.2. Howevｅｒ, ｉf the sheａｒwallｓheａr sｐａｎｒatiｏof ｌess than two couｐlinｇｂeａms sｐan of ｌeｓs than ２．5, then the shear coｍｐres ｓiｏn rａｔiｏis noｔgreaｔer thａn 0.15. Thｅｏther haｎｄ，ｔhe bｏttom oｆthe fraｍe ｓhｅar walｌstructure ｔo enhａnce tｈｅdｅsign sｈould ｎoｔbe leｓs thaｎ２０0mmａnd noｔlesｓthaｎstorey 1/１6，othｅｒｐaｒtｓｓhｏulｄnot be lｅss than 160mm ａnd ｎｏt ｌｅss thaｎｓtoｒey １/20. Arounｄthe wall of the frame ｓhｅar ｗall strucｔure sｈｏulｄbe set ｔo the beａm or dark bｅamａnd the sｉｄe columｎｔｏform a borｄｅr. Ｈoｒizｏntａl ｄｉｓtrｉbuｔioｎoｆsｈear waｌls cａn from the sheａr effect，tｈｉs design wｈen ｂuilｄｉng higｈｅr longeｒor fｒaｍｅｓtructｕre reinfoｒcｅment shｏuld be aｐprｏpｒiatelｙincｒeａｓed, ｅspｅcｉａlｌy in the sｅnｓitivｅｐarts of the beam pｏsition ｏr teｍperaｔuｒe, stiffnｅsｓchａnge is besｔappｒopriatｅly increased, ｔｈeｎcｏnsidｅration sｈoulｄbe ｇｉveｎｔo the wａlｌvertｉcaｌreiｎforｃemeｎt,becaｕse ｉt is mａinly fｒom the bｅnding efｆecｔ, aｎｄtake in ｓome ｍｕlti-ｓtorｅｙshｅａｒｗａll structuｒereinforcｅｄreｉnｆorceｍent rate -likｅlｅsｓconｓtｒained edgｅｏｆｔhｅcomｐonent or components reinforｃemeｎt of thｅedge ｃomｐｏnent.Referｅnces: [1 sad Hａyaｓhi,He Yaming. Ｏn the shorｔshｅar ｗall ｈigh-riｓe bｕilｄinｇｄesign ［J]．Kｅｙｕaｎ, 2008, (O2).高层框架剪力墙结构设计吴继成摘要: 本文从框架剪力墙结构设计的基本概念人手, 分析了框架剪力墙的构造设计内容, 包括抗震墙、剪跨比等的设计, 并出混凝土结构中最常用的框架剪力墙结构设计的注意要点。

道路桥梁专业中英文对照---毕业设计论文外文文献翻译

附录一英文翻译原文AUTOMATIC DEFLECTION AND TEMPERATURE MONITORING OFA BALANCED CANTILEVER CONCRETE BRIDGEby Olivier BURDET, Ph.D.Swiss Federal Institute of Technology, Lausanne, SwitzerlandInstitute of Reinforced and Prestressed Concrete SUMMARYThere is a need for reliable monitoring systems to follow the evolution of the behavior of structures over time.Deflections and rotations are values that reflect the overall structure behavior. This paper presents an innovative approach to the measurement of long-term deformations of bridges by use of inclinometers. High precision electronic inclinometers can be used to follow effectively long-term rotations without disruption of the traffic. In addition to their accuracy, these instruments have proven to be sufficiently stable over time and reliable for field conditions. The Mentue bridges are twin 565 m long box-girder post-tensioned concrete highway bridges under construction in Switzerland. The bridges are built by the balanced cantilever method over a deep valley. The piers are 100 m high and the main span is 150 m. A centralized data acquisition system was installed in one bridge during its construction in 1997. Every minute, the system records the rotation and temperature at a number of measuring points. The simultaneous measurement of rotations and concrete temperature at several locations gives a clear idea of the movements induced by thermal conditions. The system will be used in combination with a hydrostatic leveling setup to follow the long-term behavior of the bridge. Preliminary results show that the system performs reliably and that the accuracy of the sensors is excellent.Comparison of the evolution of rotations and temperature indicate that the structure responds to changes in air temperature rather quickly.1.BACKGROUNDAll over the world, the number of structures in service keeps increasing. With the development of traffic and the increased dependence on reliable transportation, it is becoming more and more necessary to foresee and anticipate the deterioration of structures. In particular,for structures that are part of major transportation systems, rehabilitation works need to be carefully planned in order to minimize disruptions of traffic. Automatic monitoring of structures is thus rapidly developing.Long-term monitoring of bridges is an important part of this overall effort to attempt to minimize both the impact and the cost of maintenance and rehabilitation work of major structures. By knowing the rate of deterioration of a given structure, the engineer is able to anticipate and adequately define the timing of required interventions. Conversely, interventions can be delayed until the condition of the structure requires them, without reducing the overall safety of the structure.The paper presents an innovative approach to the measurement of long-term bridge deformations. The use of high precision inclinometers permits an effective, accurate and unobtrusive following of the long-term rotations. The measurements can be performed under traffic conditions. Simultaneous measurement of the temperature at several locations gives a clear idea of the movements induced by thermal conditions and those induced by creep and shrinkage. The system presented is operational since August 1997 in the Mentue bridge, currently under construction in Switzerland. The structure has a main span of 150 m and piers 100 m high.2. LONG-TERM MONITORING OF BRIDGESAs part of its research and service activities within the Swiss Federal Institute of Technology in Lausanne (EPFL), IBAP - Reinforced and Prestressed Concrete has been involved in the monitoring of long-time deformations of bridges and other structures for over twenty-five years [1, 2, 3, 4]. In the past, IBAP has developed a system for the measurement of long-term deformations using hydrostatic leveling [5, 6]. This system has been in successful service in ten bridges in Switzerland for approximately ten years [5,7]. The system is robust, reliable and sufficiently accurate, but it requires human intervention for each measurement, and is not well suited for automatic data acquisition. One additional disadvantage of this system is that it is only easily applicable to box girder bridges with an accessible box.Occasional continuous measurements over periods of 24 hours have shown that the amplitude of daily movements is significant, usually amounting to several millimeters over a couple of hours. This is exemplified in figure 1, where measurements of the twin Lutrive bridges, taken over a period of several years before and after they were strengthened by post-tensioning, areshown along with measurements performed over a period of 24 hours. The scatter observed in the data is primarily caused by thermal effects on the bridges. In the case of these box-girder bridges built by the balanced cantilever method, with a main span of 143.5 m, the amplitude of deformations on a sunny day is of the same order of magnitude than the long term deformation over several years.Instantaneous measurements, as those made by hydrostatic leveling, are not necessarily representative of the mean position of the bridge. This occurs because the position of the bridge at the time of the measurement is influenced by the temperature history over the past several hours and days. Even if every care was taken to perform the measurements early in the morning and at the same period every year, it took a relatively long time before it was realized that the retrofit performed on the Lutrive bridges in 1988 by additional post-tensioning [3, 7,11] had not had the same effect on both of them.Figure 1: Long-term deflections of the Lutrive bridges, compared to deflections measured in a 24-hour period Automatic data acquisition, allowing frequent measurements to be performed at an acceptable cost, is thus highly desirable. A study of possible solutions including laser-based leveling, fiber optics sensors and GPS-positioning was performed, with the conclusion that, provided that their long-term stability can be demonstrated, current types of electronic inclinometers are suitable for automatic measurements of rotations in existing bridges [8].3. MENTUE BRIDGESThe Mentue bridges are twin box-girder bridges that will carry the future A1 motorway from Lausanne to Bern. Each bridge, similar in design, has an overall length of approximately 565 m, and a width of 13.46 m, designed to carry two lanes of traffic and an emergency lane. The bridges cross a deep valley with steep sides (fig. 2). The balanced cantilever design results from a bridge competition. The 100 m high concrete piers were built using climbing formwork, after which the construction of the balanced cantilever started (fig. 3).4. INCLINOMETERSStarting in 1995, IBAP initiated a research project with the goal of investigating the feasibility of a measurement system using inclinometers. Preliminary results indicated that inclinometers offer several advantages for the automatic monitoring of structures. Table 1 summarizes the main properties of the inclinometers selected for this study.One interesting property of measuring a structure’s rotations, is that, for a given ratio of maximum deflection to span length, the maximum rotation is essentially independent from its static system [8]. Since maximal allowable values of about 1/1,000 for long-term deflections under permanent loads are generally accepted values worldwide, developments made for box-girder bridges with long spans, as is the case for this research, are applicable to other bridges, for instance bridges with shorter spans and other types of cross-sections. This is significant because of the need to monitor smaller spans which constitute the majority of all bridges.The selected inclinometers are of type Wyler Zerotronic ±1°[9]. Their accuracy is 1 microradian (μrad), which corresponds to a rotation of one millimeter per kilometer, a very small value. For an intermediate span of a continuous beam with a constant depth, a mid-span deflection of 1/20,000 would induce a maximum rotation of about 150 μrad, or 0.15 milliradians (mrad).One potential problem with electronic instruments is that their measurements may drift overtime. To quantify and control this problem, a mechanical device was designed allowing the inclinometers to be precisely rotated of 180° in an horizontal plane (fig. 4). The drift of each inclinometer can be very simply obtained by comparing the values obtained in the initial and rotated position with previously obtained values. So far, it has been observed that the type of inclinometer used in this project is not very sensitive to drifting.5. INSTRUMENTATION OF THE MENTUE BRIDGESBecause a number of bridges built by the balanced cantilever method have shown an unsatisfactory behavior in service [2, 7,10], it was decided to carefully monitor the evolution of the deformations of the Mentue bridges. These bridges were designed taking into consideration recent recommendations for the choice of the amount of posttensioning [7,10,13]. Monitoring starting during the construction in 1997 and will be pursued after the bridges are opened to traffic in 2001. Deflection monitoring includes topographic leveling by the highway authorities, an hydrostatic leveling system over the entire length of both bridges and a network of inclinometers in the main span of the North bridge. Data collection iscoordinated by the engineer of record, to facilitate comparison of measured values. The information gained from these observations will be used to further enhance the design criteria for that type of bridge, especially with regard to the amount of post-tensioning [7, 10, 11, 12, 13].The automatic monitoring system is driven by a data acquisition program that gathers and stores the data. This system is able to control various types of sensors simultaneously, at the present time inclinometers and thermal sensors. The computer program driving all the instrumentation offers a flexible framework, allowing the later addition of new sensors or data acquisition systems. The use of the development environment LabView [14] allowed to leverage the large user base in the field of laboratory instrumentation and data analysis. The data acquisition system runs on a rather modest computer, with an Intel 486/66 Mhz processor, 16 MB of memory and a 500 MB hard disk, running Windows NT. All sensor data are gathered once per minute and stored in compressed form on the hard disk. The system is located in the box-girder on top of pier 3 (fig. 5). It can withstand severe weather conditions and will restart itself automatically after a power outage, which happened frequently during construction.6. SENSORSFigure 5(a) shows the location of the inclinometers in the main span of the North bridge. The sensors are placed at the axis of the supports (①an d⑤), at 1/4 and 3/4 (③an d④) of the span and at 1/8 of the span for②. In the cross section, the sensors are located on the North web, at a height corresponding to the center of gravity of the section (fig.5a). The sensors are all connected by a single RS-485 cable to the central data acquisition system located in the vicinity of inclinometer ①. Monitoring of the bridge started already during its construction. Inclinometers①,②and③were installed before the span was completed. The resulting measurement were difficult to interpret, however, because of the wide variations of angles induced by the various stages of this particular method of construction.The deflected shape will be determined by integrating the measured rotations along the length of the bridge (fig.5b). Although this integration is in principle straightforward, it has been shown [8, 16] that the type of loading and possible measurement errors need to be carefully taken into account.Thermal sensors were embedded in concrete so that temperature effects could be taken into account for the adjustment of the geometry of the formwork for subsequent casts. Figure 6 shows the layout of thermal sensors in the main span. The measurement sections are located at the same sections than the inclinometers (fig. 5). All sensors were placed in the formwork before concreting and were operational as soon as the formwork was removed, which was required for the needs of the construction. In each section, seven of the nine thermal sensor (indicated in solid black in fig. 6) are now automatically measured by the central data acquisition system.7. RESULTSFigure 7 shows the results of inclinometry measurements performed from the end ofSeptember to the third week of November 1997. All inclinometers performed well during that period. Occasional interruptions of measurement, as observed for example in early October are due to interruption of power to the system during construction operations. The overall symmetry of results from inclinometers seem to indicate that the instruments drift is not significant for that time period. The maximum amplitude of bridge deflection during the observed period, estimated on the basis of the inclinometers results, is around 40 mm. More accurate values will be computed when the method of determination ofdeflections will have been further calibrated with other measurements. Several periods of increase, respectively decrease, of deflections over several days can be observed in the graph. This further illustrates the need for continuous deformation monitoring to account for such effects. The measurement period was .busy. in terms of construction, and included the following operations: the final concrete pours in that span, horizontal jacking of the bridge to compensate some pier eccentricities, as well as the stressing of the continuity post-tensioning, and the de-tensioning of the guy cables (fig. 3). As a consequence, the interpretation of these measurements is quite difficult. It is expected that further measurements, made after the completion of the bridge, will be simpler to interpret.Figure 8 shows a detail of the measurements made in November, while figure.9 shows temperature measurements at the top and bottom of the section at mid-span made during that same period. It is clear that the measured deflections correspond to changes in the temperature. The temperature at the bottom of the section follows closely variations of the air temperature(measured in the shade near the north web of the girder). On the other hand, the temperature at the top of the cross section is less subject to rapid variations. This may be due to the high elevation of the bridge above ground, and also to the fact that, during the measuring period, there was little direct sunshine on the deck. The temperature gradient between top and bottom of the cross section has a direct relationship with short-term variations. It does not, however, appear to be related to the general tendency to decrease in rotations observed in fig. 8.8. FUTURE DEVELOPMENTSFuture developments will include algorithms to reconstruct deflections from measured rotations. To enhance the accuracy of the reconstruction of deflections, a 3D finite element model of the entire structure is in preparation [15]. This model will be used to identify the influence on rotations of various phenomena, such as creep of the piers and girder, differential settlements, horizontal and vertical temperature gradients or traffic loads.Much work will be devoted to the interpretation of the data gathered in the Mentue bridge. The final part of the research project work will focus on two aspects: understanding the very complex behavior of the structure, and determining the most important parameters, to allow a simple and effective monitoring of the bridges deflections.Finally, the research report will propose guidelines for determination of deflections from measured rotations and practical recommendations for the implementation of measurement systems using inclinometers. It is expected that within the coming year new sites will be equipped with inclinometers. Experiences made by using inclinometers to measure deflections during loading tests [16, 17] have shown that the method is very flexible and competitive with other high-tech methods.As an extension to the current research project, an innovative system for the measurement of bridge joint movement is being developed. This system integrates easily with the existing monitoring system, because it also uses inclinometers, although from a slightly different type.9. CONCLUSIONSAn innovative measurement system for deformations of structures using high precision inclinometers has been developed. This system combines a high accuracy with a relatively simple implementation. Preliminary results are very encouraging and indicate that the use of inclinometers to monitor bridge deformations is a feasible and offers advantages. The system is reliable, does not obstruct construction work or traffic and is very easily installed. Simultaneous temperature measurements have confirmed the importance of temperature variations on the behavior of structural concrete bridges.10. REFERENCES[1] ANDREY D., Maintenance des ouvrages d’art: méthodologie de surveillance, PhD Dissertation Nr 679, EPFL, Lausanne, Switzerland, 1987.[2] BURDET O., Load Testing and Monitoring of Swiss Bridges, CEB Information Bulletin Nr 219, Safety and Performance Concepts, Lausanne, Switzerland, 1993.[3] BURDET O., Critères pour le choix de la quantitéde précontrainte découlant de l.observation de ponts existants, CUST-COS 96, Clermont-Ferrand, France, 1996.[4] HASSAN M., BURDET O., FAVRE R., Combination of Ultrasonic Measurements and Load Tests in Bridge Evaluation, 5th International Conference on Structural Faults and Repair, Edinburgh, Scotland, UK, 1993.[5] FAVRE R., CHARIF H., MARKEY I., Observation à long terme de la déformation des ponts, Mandat de Recherche de l’OFR 86/88, Final Report, EPFL, Lausanne, Switzerland, 1990.[6] FAVRE R., MARKEY I., Long-term Monitoring of Bridge Deformation, NATO Research Workshop, Bridge Evaluation, Repair and Rehabilitation, NATO ASI series E: vol. 187, pp. 85-100, Baltimore, USA, 1990.[7] FAVRE R., BURDET O. et al., Enseignements tirés d’essais de charge et d’observations à long terme pour l’évaluation des ponts et le choix de la précontrainte, OFR Report, 83/90, Zürich, Switzerland, 1995.[8] DAVERIO R., Mesures des déformations des ponts par un système d’inclinométrie,Rapport de maîtrise EPFL-IBAP, Lausanne, Switzerland, 1995.[9] WYLER AG., Technical specifications for Zerotronic Inclinometers, Winterthur, Switzerland, 1996.[10] FAVRE R., MARKEY I., Generalization of the Load Balancing Method, 12th FIP Congress, Prestressed Concrete in Switzerland, pp. 32-37, Washington, USA, 1994.[11] FAVRE R., BURDET O., CHARIF H., Critères pour le choix d’une précontrainte: application au cas d’un renforcement, "Colloque International Gestion des Ouvrages d’Art: Quelle Stratégie pour Maintenir et Adapter le Patrimoine, pp. 197-208, Paris, France, 1994. [12] FAVRE R., BURDET O., Wahl einer geeigneten Vorspannung, Beton- und Stahlbetonbau, Beton- und Stahlbetonbau, 92/3, 67, Germany, 1997.[13] FAVRE R., BURDET O., Choix d’une quantité appropriée de précontrain te, SIA D0 129, Zürich, Switzerland, 1996.[14] NATIONAL INSTRUMENTS, LabView User.s Manual, Austin, USA, 1996.[15] BOUBERGUIG A., ROSSIER S., FAVRE R. et al, Calcul non linéaire du béton arméet précontraint, Revue Français du Génie Civil, vol. 1 n° 3, Hermes, Paris, France, 1997. [16] FEST E., Système de mesure par inclinométrie: développement d’un algorithme de calcul des flèches, Mémoire de maîtrise de DEA, Lausanne / Paris, Switzerland / France, 1997.[17] PERREGAUX N. et al., Vertical Displacement of Bridges using the SOFO System: a Fiber Optic Monitoring Method for Structures, 12th ASCE Engineering Mechanics Conference, San Diego, USA, to be published,1998.译文平衡悬臂施工混凝土桥挠度和温度的自动监测作者Olivier BURDET博士瑞士联邦理工学院，洛桑，瑞士钢筋和预应力混凝土研究所概要：我们想要跟踪结构行为随时间的演化，需要一种可靠的监测系统。

土木工程毕业设计--外文翻译

1 Introduction and scope1.1 Aims of the ManualThis Manual provides guidance on the design of reinforced and prestressed concrete building structures. Structures designed in accordance with this Manual will normally comply with DD ENV 1992-1-1: 19921 (hereinafter referred to as EC2).1.2 Eurocode systemThe structural Eurocodes were initiated by the European Commission but are now produced by the Comité Européen de Normalisation (CEN) which is the European standards organization, its members being the national standards bodies of the EU and EFTA countries,e.g. BSI.CEN will eventually publish these design standards as full European Standards EN (Euronorms), but initially they are being issued as Prestandards ENV. Normally an ENV has a life of about 3 years to permit familiarization and trial use of the standard by member states. After formal voting by the member bodies, ENVs are converted into ENs taking into account the national comments on the ENV document. At present the following Eurocode parts have been published as ENVs but as yet none has been converted to an EN:DD ENV 1991-1-1: Basis of design and actions on structures (EC1)DD ENV 1992-1-1: Design of concrete structures (EC2)DD ENV 1993-1-1: Design of steel structures (EC3)DD ENV 1994-1-1: Design of composite steel and concrete structures (EC4)DD ENV 1995-1-1: Design of timber structures (EC5)DD ENV 1996-1-1: Design of masonry structures (EC6)DD ENV 1997-1-1: Geotechnical design (EC7)DD ENV 1998-1-1: Earthquake resistant design of structures (EC8)DD ENV 1999-1-1: Design of aluminium alloy structures (EC9)Each Eurocode is published in a number of parts, usually with ‘General rules’ and ‘Rules for buildings’ in Part 1. The various parts of EC2 are:Part 1.1 General rules and rules for buildings;Part 1.2 Supplementary rules for structural fire design;Part 1.3 Supplementary rules for precast concrete elements and structures;Part 1.4 Supplementary rules for the use of lightweight aggregate concrete;Part 1.5 Supplementary rules for the use of unbonded and external prestressing tendons;Part 1.6 Supplementary rules for plain or lightly reinforced concrete structures;Part 2.0 Reinforced and prestressed concrete bridges;Part 3.0 Concrete foundations;Part 4.0 Liquid retaining and containment structures.All Eurocodes follow a common editorial style. The codes contain ‘Principles’ and‘Application rules’. Principles are general statements, definitions, requirements and sometimes analytical models. All designs must comply with the Principles, and no alternative is permitted. Application rules are rules commonly adopted in design. They follow the Principles and satisfy their requirements. Alternative rules may be used provided that compliance with the Principles can be demonstrated.Some parameters in Eurocodes are designated by | _ | , commonly referred to as boxed values. The boxed values in the Codes are indicative guidance values. Each member state is required to fix the boxed value applicable within its jurisdiction. Such information would be found in the National Application Document (NAD) which is published as part of each ENV.There are also other purposes for NADs. NAD is meant to provide operational information to enable the ENV to be used. For certain aspects of the design, the ENV may refer to national standards or to CEN standard in preparation or ISO standards. The NAD is meant to provide appropriate guidance including modifications required to maintain compatibility between the documents. Very occasionally the NAD might rewrite particular clauses of the code in the interest of safety or economy. This is however rare.1.3 Scope of the ManualThe range of structures and structural elements covered by the Manual is limited to building structures that do not rely on bending in columns for their resistance to horizontal forces and are also non-sway. This will be found to cover the vast majority of all reinforced and prestressed concrete building structures. In using the Manual the following should be noted:• The Manual has been drafted to comply with ENV 1992-1-1 together with the UK NAD• Although British Standards have been referenced as loading codes in Sections 3 and 6,to comply with the UK NAD, the Manual can be used in conjunction with other loading codes • The structures are braced and non-sway• The concrete is of normal weight• The structure is predominantly in situ• Prestressed concrete members have bonded or unbonded internal tendons• The Manual can be used in conjunction with all commonly used materials in construction; however the data given are limited to the following:– concrete up to characteristic cylinder strength of 50N/mm2 (cube strength 602N/mm)– high-tensile reinforcement with characteristic strength of 4602N/mm– mild-steel reinforcement with characteristic strength of 2502N/mm– prestressing tendons with 7-wire low-relaxation (Class 2) strands• High ductility (Class H) has been assumed for:– all ribbed bars and grade 250 bars, and– ribbed wire welded fabric in wire sizes of 6mm or over• Normal ductility (Class N) has been assumed for plain or indented wire welded fabric.For structures or elements outside this scope EC2 should be used.1.4 Contents of the ManualThe Manual covers the following design stages:• gene ral principles that govern the design of the layout of the structure• initial sizing of members• estimating of quantities of reinforcement and prestressing tendons• final design of members.2 General principlesThis section outlines the general principles that apply to both initial and final design of both reinforced and prestressed concrete building structures, and states the design parameters that govern all design stages.2.1 GeneralOne engineer should be responsible for the overall design, including stability, and should ensure the compatibility of the design and details of parts and components even where some or all of the design and details of those parts and components are not made by the same engineer.The structure should be so arranged that it can transmit dead, wind and imposed loads in a direct manner to the foundations. The general arrangement should ensure a robust and stable structure that will not collapse progressively under the effects of misuse or accidental damage to any one element.The engineer should consider engineer site constraints, buildability2, maintainability and decommissioning.The engineer should take account of his responsibilities as a ‘Designer’ under the Construction (Design & Management) Regulations.32.2 StabilityLateral stability in two orthogonal directions should be provided by a system of strongpoints within the structure so as to produce a braced non-sway structure, in which the columns will not be subject to significant sway moments. Strongpoints can generally be provided by the core walls enclosing the stairs, lifts and service ducts. Additional stiffness can be provided by shear walls formed from a gable end or from some other external or internal subdividing wall. The core and shear walls should preferably be distributed throughout the structure and so arranged that their combined shear centre is located approximately on the line of the resultant in plan of the applied overturning forces. Where this is not possible, the resulting twisting moments must be considered when calculating the load carried by each strongpoint. These walls should generally be of reinforced concrete not less than 180mm thick to facilitate concreting, but they may be of 215mm brickwork or 190mm solid blockwork properly tied and pinned up to the framing for low- to medium-rise buildings.Strongpoints should be effective throughout the full height of the building. If it is essential for strongpoints to be discontinuous at one level, provision must be made to transfer the forces toother vertical components.It is essential that floors be designed to act as horizontal diaphragms, particularly if precast units are used.Where a structure is divided by expansion joints each part should be structurally independent and designed to be stable and robust without relying on the stability of adjacent sections.2.3 RobustnessAll members of the structure should be effectively tied together in the longitudinal, transverse and vertical directions.A well-designed and well-detailed cast-in situ structure will normally satisfy the detailed tying requirements set out in subsection 5.11.Elements whose failure would cause collapse of more than a limited part of the structure adjacent to them should be avoided. Where this is not possible, alternative load paths should be identified or the element in question strengthened.2.4 Movement jointsMovement joints may need to be provided to minimize the effects of movements caused by, for example, shrinkage, temperature variations, creep and settlement.The effectiveness of movement joints depends on their location. Movement joints should divide the structure into a number of individual sections, and should pass through the whole structure above ground level in one plane. The structure should be framed on both sides of the joint. Some examples of positioning movement joints in plan are given in Fig. 2.1.Movement joints may also be required where there is a significant change in the type of foundation or the height of the structure. For reinforced concrete frame structures in UK conditions, movement joints at least 25mm wide should normally be provided at approximately 50m centres both longitudinally and transversely. In the top storey and for open buildings and exposed slabs additional joints should normally be provided to give approximately 25m spacing. Joint spacing in exposed parapets should be approximately 12m.Joints should be incorporated in the finishes and in the cladding at the movement joint locations.2.5 Fire resistance and durabilityFor the required period of fire resistance (prescribed in the Building Regulations), the structure should:• have adequate loadbearing capacity• limit the temperature rise on the far face by sufficient insulation, and• have sufficient integrity to prevent the formation of crack s that will allow the passage of fire and gases.Fig. 2.1 Location of movement jointsThe design should take into account the likely deterioration of the structure and its components in their environment having due regard to the anticipated level of maintenance. The following inter-related factors should be considered:• the required performance criteria• the expected environmental conditions• the composition, properties and performance of materials• the shape of members and detailing• the quality of workmanship• any protective measure• the likely maintenance during the intended life.Concrete of appropriate quality with adequate cover to the reinforcement should be specified. The above requirements for durability and fire resistance may dictate sizes for members greater than those required for structural strength alone.3 Design principles – reinforced concrete3.1 LoadingThe loads to be used in calculations are:(a) Characteristic dead load,k G : the weight of the structure complete with finishes, fixtures and fixed partitions (BS 4648)(b) Characteristic imposed load,k Q (BS6399，Parts1and 53)(c) Characteristic wind load, W k (90% of the load derived from CP3, Chapter V, Part 62)* (d) Nominal earth load,n E (BS 78004)(e) At the ultimate limit state the horizontal forces to be resisted at any level should be the greater of:(i) 1.5% of the characteristic dead load above that level, or(ii) 90% of the wind load derived from CP3, Chapter V, Part 62, multiplied by the appropriate partial safety factor.The horizontal forces should be distributed between the strongpoints according to their stiffness.In using the above documents the following modifications should be noted:(f) The imposed floor loads of a building should be treated as one load to which the reduction factors given in BS 6399: Part 1:51996are applicable.(g) Snow drift loads obtained from BS 6399: Part 3:51998 should be multiplied by 0.7 and treated in a similar way to an imposed load and not as an accidental load.3.2 Limit statesThis Manual adopts the limit-state principle and the partial factor format of EC2.3.2.1 Ultimate limit stateThe design loads are obtained by multiplying the characteristic loads by the appropriate partial factor f from Table 3.1.The ‘adverse’ and ‘beneficial’ factors should be used so as to produce the most onerous condition.3.2.2 Serviceability limit statesProvided that span/effective depth ratios and bar diameter and spacing rules are observedit will not be necessary to check for serviceability limit states.fThe Table uses the simplified combination permitted in EC2.†For pressures arising from an accidental head of water at ground level a partial factor of 1.15 may be used.3.3 Material and design stressesDesign stresses are given in the appropriate sections of the Manual. It should be noted that EC2 specifies concrete strength class by both the cylinder strength and cube strength (for exampleN/mm at 28 days). C25/30 is a concrete with cylinder strength of 25 and cube strength of 302Standard strength classes are C20/25, C25/30, C30/37, C35/45, C40/50, C45/55 and C50/60. All design equations which include concrete compressive strength use the characteristic 28 day cylinder strength,f.ckPartial factors for concrete are 1.5 for ultimate limit state and 1.0 for serviceability limit state. The strength properties of reinforcement are expressed in terms of the characteristic yield strength,f.ykPartial factors for reinforcement steel are 1.15 for ultimate limit state and 1.0 for serviceability limit state.4 Initial design – reinforced concrete4.1 IntroductionIn the initial stages of the design of building structures it is necessary, often at short notice,to produce alternative schemes that can be assessed for architectural and functional suitability and which can be compared for cost. They will usually be based on vague and limited information on matters affecting the structure such as imposed loads and nature of finishes, let alone firm dimensions, but it is nevertheless expected that viable schemes be produced on which reliable cost estimates can be based.It follows that initial design methods should be simple, quick, conservative and reliable. Lengthy analytical methods should be avoided.This section offers some advice on the general principles to be applied when preparing a scheme for a structure, followed by methods for sizing members of superstructures. Foundation design is best deferred to later stages when site investigation results can be evaluated.The aim should be to establish a structural scheme that is suitable for its purpose, sensibly economical, and not unduly sensitive to the various changes that are likely to be imposed as the overall design develops.Sizing of structural members should be based on the longest spans (slabs and beams) and largest areas of roof and/or floors carried (beams, columns, walls and foundations). The same sizes should be assumed for similar but less onerous cases – this saves design and costing time at this stage and is of actual benefit in producing visual and constructional repetition and hence, ultimately, cost benefits.Simple structural schemes are quick to design and easy to build. They may be complicated later by other members of the design team trying to achieve their optimum conditions, but a simple scheme provides a good ‘benchmark’ at the initial stage.Loads should be carried to the foundation by the shortest and most direct routes. In constructional terms, simplicity implies (among other matters) repetition; avoidance of congested, awkward or structurally sensitive details and straightforward temporary works with minimal requirements for unorthodox sequencing to achieve the intended behaviour of the completed structure.Standardized construction items will usually be cheaper and more readily available than purpose-made items.4.2 LoadsLoads should be based on BS 4648，BS6399：Parts1 and 53 andCP3：ChapterV ：Part 62Imposed loading should initially be taken as the highest statutory figures where options exist. The imposed load reduction allowed in the loading code should not be taken advantage of in the initial design stage except when assessing the load on the foundations.Loading should be generous and not less than the following in the initial stages:floor finish (screed) 1.82kN/mmceiling and service load 0.52kN/mmAllowance for:demountable lightweight partitions* 1.02kN/mmblockwork partitions† 2.52kN/mmWeight of reinforced concrete should be taken as 243kN/mDesign loads should be obtained using Table 3.1.4.3 Material propertiesFor normal construction in the UK, a characteristic cylinder concrete strength ck f of 252N/mm should be assumed for the initial design. In areas with poor aggregates this may have to be reduced.For UK steels a characteristic strength yk f of 4602N/mm should be used for high-tensile reinforcement and 2502N/mm for mild steel.4.4 Structural form and framingThe following measures should be adopted:(a) provide stability against lateral forces and ensure braced construction by arranging suitable shear walls deployed symmetrically wherever possible(b) adopt a simple arrangement of slabs, beams and columns so that loads are carried to the foundations by the shortest and most direct routes(c) allow for movement joints (see subsection 2.4)(d) choose an arrangement that will limit the span of slabs to 5m to 6m and beam spans to 8m to l0m on a regular grid; for flat slabs restrict column spacings to 8m(e) adopt a minimum column size of 300mm × 300mm or equivalent area(f) provide a robust structure.The arrangement should take account of possible large openings for services and problems with foundations, e.g. columns immediately adjacent to site boundaries may require balanced or other special foundations.4.5 Fire resistance and durabilityThe size of structural members may be governed by the requirement of fire resistance and may also be affected by the cover necessary to ensure durability. Table 4.1 shows the minimum practical member sizes for different periods of fire resistance and the cover to the main reinforcement required for continuous members in dry and humid environments without frost. For other exposure classes, cover should be increased. For simply supported members, sizes and cover should be increased (see Section 5 and Appendix C).4.6 StiffnessTo provide adequate stiffness, the effective depths of beams, slabs and the waist of stairs should not be less than those derived from Table 4.2.Beams should be of sufficient depth to avoid the necessity for excessive compression reinforcement and to ensure that economical amounts of tension and shear reinforcement are provided. This will also facilitate the placing of concrete.*To be treated as imposed loads.†To be treated as dead load s when the layout is fixed.Table 4.1 Minimum member sizes and cover† for initial design of continuous members†C over is to main reinforcement.Table 4.2 Basic ratios of span/effective depth for initial design (yk f = 4602N/mm )1. For two-way spanning slabs (supported on beams), the check on the ratio of span/effective depth should be carried out on the shorter span. For flat slabs, the longer span should be taken.2. For flanged sections with the ratio of the flange to the rib width greater than 3, the Table value should be multiplied by 0.8.3. For members, other than flat slab panels, which support partitions liable to be damaged by excessive deflection of the member, and where the span exceeds 7m, the Table value should be multiplied by 7/span.4. For flat slabs where the greater span exceeds 8.5m, the Table value should be multiplied by 8.5/span.第一章引言和适用范围1.1手册的作用这本手册为设计钢筋和预应力混凝土建筑结构提供了指导。

公路工程毕业设计摘要及翻译汇总

摘要交通运输事业是国民经济的重要组成部分，是国民经济的命脉，是联系工业和农业、城市和乡村、生产和消费的纽带。

它在国家的政治、经济、军事、文化建设中具有重要作用。

一级公路是连接高速公路或是某些大城市的城乡结合部、开发区经济带及人烟稀少地区的干线公路，一级公路的建成对长春市和沈阳市这两个省会城市的政治、经济、文化的交流和发展会起到积极的作用。

对东北地区来说，公路的建设意义深远，选择交通作为合作的突破口，无疑是注重实效的选择。

实现交通的多面化，既是行业协调发展，为社会提供优良交通环境的需要，也是振兴东北老工业基地，全面实现小康社会目标的需要，是实现经济一体化，促进区域经济共同协调发展的需要。

**一级公路全长2350m，主要设计的有横断面设计,平面线形设计,纵断面设计,路面结构设计等。

平面设计的主要内容是线形设计，同时要考虑行车视距问题。

纵断面设计主要是纵坡及坡长设计。

路面为沥青混凝土路面结构类型，**一级公路的建成将对于两个省会城市区域间的发展和建设具有重要意义。

关键词：一级公路；路线设计；路面ABSTRACTTransport industry is an important part of the national economy，the lifeline of national economy，and. It is associated industry and agriculture, urban and rural areas, production and consumption of a link. It plays an important role in the country's political, economic, military,and culture.A highway is to connect some of the urban cities, economic development zones and sparsely populated areas with the main highway，Northeast region, the construction of roads far-reaching, select traffic as a breakthrough, and no doubt a pragmatic choice，To achieve transport of multi-faceted, coordinated development of both industries, and provide good traffic environment needs, but also the revitalization of northeast old industrial base, the full realization of the objectives of a well-off society needs to achieve economic integration, promoting regional economic co-coordinated development.The length of Shen Chang-arterial road is 2350m. The main design elements are cross-sectional design, the design of horizontal alignment, vertical section design, pavement structure design.The main elements of graphic design is the linear design, at the same time horizon to consider the issue of traffic.Profile Design is the design of longitudinal and slope length. Asphalt concrete pavement is the type of pavement structure It is great significance of Shen Chang-arterial road-building for regional development and building .Keywords: Arterial road ; Route design ; Pavement design摘要本设计是平原微丘区一级公路的方案设计。

《公路线形设计》外文文献(中英对照)

外文文献翻译（含：英文原文及中文译文）文献出处：Y Hassan. Geometric Design of Highways[J] Advance s in Transportation Studies, 2016, 6(1):31-41.英文原文Geometric De s ign of Highway sYHassanA.Alignment De s i gnThe alignment of a road is shown on the plane view and is a s erie s of straight line s called tangen ts connected by circular curve s. In modem practice it is common to interpo s e tran s ition or s piral curve s between tangent s and circular curve s.The line s hape should be continuou s, s udden changes from flat line to small radiu s curve or s udden change of long line end connected to s mall radius curve s hould be a v oided, otherwise a traffic accident may occur. Similarly, arc s with different radii end-to-end (complex curves) or s hort straight line s between two arcs with different radii are bad line s unle ss an easing curve is in s erted between arcs. The long, s mooth curve is alwa ys a good line becau s e it is beaut 血lly lined and will not be abandoned in the future. However, it is not ideal that the two-way road line s hape is compo s ed entirely of curve s, becau s e s ome driver s alway s he s itate to pas s through curved road s egment s. The long and s low curve is used in thesmaller comer s. If you u s e a s hort curve, you will s ee "kinks." In addition, the de s ign of the flat and v ertical s ections of the line s hould be con s idered comprehen s ively and s hould not be only one. No matter which, for example, when the s tarting point of the flat curve is near the vertex of the vertical curve, s eriou s traffic accident s will o ccur.Vehicle s driving on curved s ection s are s ubjected to centrifugal force, and they need a force of the s ame magnitude in the oppo s ite direction due to the height and lateral friction to off s et it. From the viewpoint of highway de s ign, the high or horizontal friction cannot exceed a certain v alue. Them 邸imum, the s e control v alues for a certain design s peed may limit the curvature of the curve. In generai the curvature of a c 订c u lar curve is repre s ented by it s radius. For the linear de s ign, the curvature is often de s cribed by the curvature, ie, the central angle corre s ponding to the 100-foot curve, which is in v er s ely proportional to the radiu s of the curve.A normal road arch is s et in a s traight s ection of the road, and the curve section is s et to a super high, and an exces s i v ely gradual road s ection must be s et between the norn 叫s ection and the s uper high s ection. The usual practice is to maintain the de s ign elevation of each midline of the road unchanged.B y raising the outer edge and lowering the inner edge to form a s uper high, for the line s hape where the s traight line is d 汀ec tly connected with the c 虹le curve, the s uper high s hould ne v er s tart on the straight line before reaching the curve. At the other end of the curve at acertain distance to reach all the ultra-high.If the vehicle is driving at a high speed on a restricted section of road, such as a straight line connected with a small radius circle curve, driving will be extremely uncomfortable. When the car enters the curve section, the super high starts and the vehicle tilts inward, but the passenger must maintain the body because it is not subjected to centrifugal force at this time. When the car reaches the curve section, centrifugal force suddenly occurs, forcing passengers to m狄e further posture adjustments. When the car leaves the curve, the above process is just the opposite. After inserting the relaxation curve, the radius gradually transitions from infinity to a certain fixed value on the circle curve, the centrifugal force gradually increases, and ultra-high levels are carefully set along the relaxation curve, and the centrifugal force is gradually increased, thereby avoiding driving bumps.The easement curve has been used on railways for many years, but it has recently been applied on highways. This is understandable. The train must follow a precise orbit, and the uncomfortable feeling mentioned above can only be eliminated after the ease curve is used. However, the driver of a car can change the lateral position on the road at will, and he can provide a relaxation curve for himself by m 咄ing a roundabout curve. But doing this in one lane (sometimes in other lanes) is very dangerous. A well-designed relaxation curve makes the above roundaboutnessunneces s ary. Multi-cluster s afety is a meas ure, and roads are widely u s ed as transition cUIVe s .For a circular c 田v e with the same radius, adding an ea s ing cUIVe at the end will change the relative po s itions of the c 田ve and the s traight line. Therefore, whether or not to use an easing cUIVe s ho uld be determined before final alignment sUIVe y. The s tarting point of the general cUIVe is labeled PC or BC and the end point is labeled PT or EC. For cUIVe s with transition c 田ve s, the u s ual marker configuration s are: TC, SC, CS, and ST. For two-way roads, the road width s hould be increased at sharp bend s. This is mainly based on the following factor s: 1. The dri v er is afraid to get out of the edge of the road. 2. Due to the difference in the driving trajectory of the front and rear wheels of the vehicle, the effective lateral width of the vehicle increa s es; 3. The width of the front of the vehicle that is inclined relative to the centerline of the road. For road s that are 24 feet wide, the added width is negligible. Onl y if the de s ign s peed is 30 mil / h and the cUIVature is up to 2 ft. Howe v er, for narrow road s, widening is very important e v en on s mooth cUIVe s ec tio ns . The recommended widening value s and widened de s ign s are s hown in ". Highway linear de s ign."B.Longitudinal s lope lineThe v ertical alignment of the highway and its impact on the s afety andeconomy of vehicle operation constitute one of the mo s t important element s in highway de s ign. Vertical line s consist of s traight line s and vertical parabola s or circular line s called vertical s lope line s. When a grade line rise s gradually from a horizontal line, it is called an uphili and vice ver s a, it is called a downhill slope. In the analy s is of s lope and s lope controi 如igner s usuall y have to s tud y the effect of change s in slope on the midline profile. In determining the s lope, the ideal s ituation is the balance of e x ca v ation and filling, and there is no large amount of borrower s and abandoned partie s. All the earth moving is carried down as far a s po ss ible and the distance is not long. The s lope s hould change with the terrain and be consistent w ith the direction of ascent and de s cent of the existing drainage s ystem In the mountains, the s lop e-5 s h ould be balanced to minimize the total co s t In the plain or gra ss land areas, the slope is approximatel y parallel to the s urface, but higher than the s urface at a s ufficient height to facilitate drainage of the s urface. If necessary, wind s can be used to remove s urface s no w. If the road is approaching or running along a ri v er, the current height of the s lope is determined by the expected flood le v el In any case, the gentle s lope s hould be s et at the excavation s ection compared to the s hort vertical s ection connecting the short vertical curve due to the up s lope down s lope, and the s ection from the downslope up s lope s hould be s et at the fill. Road s ection. Such a good linear de s ign can often avoid the forn 沮tion of a mound or depre ss ionopposite to the current landscape. Other consideration s are much more important when determining the vertical slope line than when filling the balance. Study and make more detailed adjustments to advanced is s ues. In general, the slope of the design that is consistent with the existing condition s is better, which can avoid some unnecessary c osts.In s lope analy s is and control, the impact of slope on motor vehicle operating co s ts is one of the most important con s iderations. As the s lope increase s, the fuel con s umption will obviously increase and the s peed will slow down. A more economical solution can balance the annual increase in the annual co s t of reducing the s lope and increasing the annual co s t of running the vehicle without increasing the s lope. The exact solution to this problem depends on the under s tanding of traffic flow and traffic type, which can only be known through traffic inve s tigation s.In different states, where the maximum longitudinal gradient is also very different, AASHTO recommend s that the maximum longitudinal slope be selected based on the time and terrain. The current de s ign ha s a maximum longitudinal gradient of 5% at a de s ign speed of 70 mil / h. At a de s ign speed of 30 mil / h, the maximum longitudinal slope is generally 7% - 12% depending on the topograph y.When using longer s ustained climb s, the s lope length cannot exceed the critical s lope length when no slow-moving v ehicle is provided. The critical s lope length can vary from 1700 ft in 3% grade to 500 ft in 8%grade. The slope of the continuou s long s lope must be le s s than the maximum slope of any end s urface of the highwa y. U s uall y the long continuou s s ingle slope is disconnected and the lower part is de s igned as a steep s lope, w hile approaching the top of the slope allow s the s lope to decrease. At the s ame time, it is nece ss ary to a v oid ob s truction of the view due to the inclination of the longitudinal s ection.The m 邸imum longitudinal gradient of the highwa y is 9%. Only when the drainage of the road is a problem, if the water must be drained to the s ide ditch or the drainage ditch, the minimum gradient criterion is of importance. In this c ase, 心HTO recommend s a minimum gradient of0.35%.C.s ight distanceIn order to en s ure the s afety of driving, the road must be designed to have a sufficient distance in front of the driver's line of s ight, s o that they can avoid ob s tacle s other than the ob s tacles, or safely overtake. The line-of-s ight is the length of the road visible to the driver of the vehicle. Two meaning s: "parking distance" or "non-pa ss ing s ight distance" or "o v ertaking s ight distance."No matter what happens, reasonable de s ign require s the dri v er to s ee this danger outside a certain distance, and brake the car before hitting it. In addition, it is not s afe to think that the v ehicle can avoid danger by leaving the driving lane. Becau s e this can cause the v ehicle to lo s e controlor to collide with another car.The parking distance is composed of two parts: The first part is the distance that the driver takes before the driver finds an obstacle and brakes. In this detection and reaction phase, the vehicle travels at its initial speed; the second part is the driver's Part of the parking distance depends on the speed of the vehicle and the driver's visual time and braking time. The second part of the parking distance depends on the speed, the brakes, the tires, the conditions of the road surface, and the line shape and slope of the road.Otherwise, the capacity of the highway will be reduced, and the accident will increase, because the irritable driver would risk a collision and overtake the vehicle if he cannot safely overtake the vehicle. The minimum distance in front of which the driver can safely be seen is called the overtaking distance.When making a decision on whether to pass or not, the driver must compare the visibility distance ahead and the distance required to complete the overta 耟ng movement. The factors that influence him to m昢e a decision are the degree of caution in driving and the acceleration performance of the vehicle. Due to the significant differences between humans, the overtaking behavior, which is mainly determined by human judgments and actions rather than the mechanical theorem, varies greatly from driver to driver. In order to establish the line-of-sight value forovertaking, engineer s ob s erved many drivers' overtaking behavior. Between 1938 and 1941, a basic survey was e s tablished to e5tablish a standard of over- sight distance. As s ume that the operating condition s area s follow s:1.It is driven at a uniform s peed by the o v ertaking v ehicle.2.Overtaking When entering the overtaking area, decelerate after being overtak:en.3.When arriving at the o v ertaking area, the driver need s to ob s erve the pas s ing area for a s hort time and start o vertaking.4.In the face of the oppo s ite vehicle, the overtaking is completed in a delayed s tart-up and a hurried turn. In the o v ertaking proce ss, o v ertaking accelerate s in the overtaking lane and the average s peed is 10 mil / h faster than being overtaken.5.When o v ertaking returns to its original lane, there must be a safe distance between it and the opposite vehicle on the other lane.The s um of the above five items is the over sight distance.中文译文公路线形设计作者：Y Has s anA.平面设计道路的线形反映在平面图上是由一系列的直线和与直线相连的圆曲线构成的。

道路工程毕业设计外文翻译---高速公路设计与施工

原文Highway Design and Construction: The Innovation Challenge Author: Robert E. Skinner Jr.Innovations and advances in research are changing the way highways are built in America.The Egyptians were pouring concrete in 2500 BC, and the Romans used it to construct the Pantheon and the Colosseum. By the mid-1800s, Europeans were building bridges with concrete, and the first “modern” concrete highway pavements appear ed in the latter part of the 19th century. Naturally occurring asphalts, which have been used for waterproofing for thousands of years, came into common use in road construction in the 1800s. The first iron bridge was constructed in 1774, but by the end of the 19th century steel had largely replaced iron in bridge construction. These materials—concrete, asphalt, and steel—are now the mainstays of highway and bridge construction throughout the world, as well as of most types of public works infrastructure. Concrete and steel, the most versatile of these materials, are used for bridges and other highway structures; concrete and asphalt are used for roadway pavements.Everyone is familiar with concrete, asphalt, and steel, and some of us have worked with them, perhaps on home improvement projects. This familiarity, coupled with the long history of their many uses, has led many otherwise technically savvy people to believe that these materials are well understood, that their performance can be easily and reliably predicted, and that the technical challenges in using them for highways were overcome long ago. However, such notions are largely incorrect and misleading.For example, consider concrete, which is a mixture of portland cement, sand, aggregate (gravel or crushed stone), and water. Its performance characteristics are determined by the proportions and characteristics of the components, as well as by how it is mixed and formed. The underlying chemical reactions of concrete are surprisingly complex, not completely understood, and vary with the type of stone. Steel may be added for tensile strength (reinforced concrete), and a variety of additives have been identified to improve the workabilityand performance of concrete in particular applications and conditions. Damage and deterioration to concrete can result from excessive loadings and environmental conditions, such as freeze-thaw cycles and chemical reactions with salts used for deicing._________________________Many factors contribute to theurgent need for innovation inhighway construction._________________________Concrete is the most heavily used substance in the world after water (Sedgwick, 1991). Worldwide, concrete construction annually consumes about 1.6 billion tons of cement, 10 billion tons of sand and crushed stone, and 1 billion tons of water (M.S. Kahn, 2007). Given transportation costs, there is a huge financial incentive to using local sources of stone, even if the properties of that stone are less than ideal. Thus concrete is not a homogenous material. In truth, an unlimited number of combinations and permutations are possible.Much the same can be said of asphalt—technically, asphaltic concrete—which is also a mixture of aggregate (gravel or crushed stone), sand, and cement (asphalt binder); economics promote the use of locally available materials; and the underlying chemistry is not well understood. The characteristics of asphalt binder, for instance, vary depending on the source of crude oil from which it is derived.The metallurgy of steel is probably better understood than the chemistry of either asphalt or concrete, but it too is a mixture with virtually limitless combinations. Strength, toughness, corrosion resistance, and weldability are some of the performance characteristics that vary with the type of steel alloy used and the intended applications.As uses evolve and economic conditions change, we have a continuing need for a more sophisticated understanding of these common materials. Even though they are “mature” products, there is still room for significant incremental improvements in their performance. Because fundamental knowledge is still wanting, there is also considerable potential for breakthroughs in their performance.Factors That Affect Highway ConstructionAll other things being equal, stronger, longer lasting, less costly highway materials are desirable and, given the quantities involved, there are plenty of incentives for innovation. In highway transportation, however, all other things are not equal. A number of other factors contribute to the urgent and continuing need for innovation.First, traffic volume and loadings continue to increase. Every day the U.S. highway network carries more traffic, including heavy trucks that were unimagined when the system wasoriginally conceived and constructed. The 47,000-mile interstate highway system today carries more traffic than the entire U.S. highway system carried in 1956 when the interstates were laid out. The U.S. Department of Transportation (DOT) estimates that in metropolitan areas the annual cost of traffic congestion for businesses and citizens is nearly $170 billion (PB Consult, Inc., 2007).On rural interstates, overall traffic more than doubled between 1970 and 2005; at the same time, the loadings on those highways increased six-fold, mainly due to the increase in the number of trucks and the number of miles they travel. (Truck traffic increased from about 5.7 percent of all vehicle-miles traveled on U.S. highways in 1965 to 7.5 percent in 2000 [FHWA, 2005]).Second, traffic disruptions must be kept to a minimum during construction. Our overstressed highway system is not very resilient. Thus disruptions of any sort, such as lane and roadway closings, especially in major metropolitan areas and on key Interstate routes, can cause massive traffic snarls. This means that repair and reconstruction operations must often be done at night, which introduces a variety of additional complexities and safety issues. Occasionally, heroic measures must be taken to keep traffic moving during construction. For example, during construction of the “Big Dig” in Boston, the elevated Central Artery was in continuous service while cut-cover tunnels were constructed directly below it.Third, environmental, community, and safety requirements have become more stringent. For many good reasons, expectations of what a highway should be, how it should operate, and how it should interact with the environment and adjacent communities are constantly evolving. Designs to promote safety, measures to mitigate a growing list of environmental impacts, and attention to aesthetics have fundamentally changed the scope of major highway projects in the United States. For example, on Maryland’s $2.4 billion Intercounty Connector project in suburban Washington, D.C., which is now under construction, environmental mitigation accounts for 15 percent of project costs, or about $15 million per mile (AASHTO, 2008). Fourth, costs continue to rise. Building and maintaining highways cost effectively is an ever-present goal of good engineering. But cost increases in highway construction have been extraordinary due in part to the expanded scope of highway projects and construction in demanding settings. In addition, the costs of the mainstay materials—portland cement, asphalt binder, and steel—have risen dramatically as the world, particularly China, has gone on a construction binge. The Federal Highway Administration’s cost indices for portland cement concrete pavement, asphalt pavement, and structural steel increased by 51 percent, 58 percent, and 70 percent respectively between 1995 and 2005 (FHWA, 2006).Fortunately, research and innovation in construction have never stopped, although they are not always sufficiently funded and they seem to fly beneath the radar of many scientists and engineers. Nevertheless, there have been great successes, which are cumulatively changing how highways are built in America.The Superpave Design SystemIn response to widespread concerns about premature failures of hot-mix asphalt pavements in the early 1980s, a well funded, congressionally mandated, crash research program was conducted to improve our understanding of asphalt pavements and their performance. The seven-year Strategic Highway Research Program (SHRP), which was managed by the National Research Council, developed a new system of standard specifications, test methods, andengineering practices for the selection of materials and the mix proportions for hot-mix asphalt pavement.The new system has improved matches between combinations of asphalt binder and crushed stone and the climatic and traffic conditions on specific highways. State departments of transportation (DOTs) spend more than $10 billion annually on these pavements, so even modest improvements in pavement durability and useful life can lead to substantial cost savings for agencies and time savings for motorists (TRB, 2001).SHRP rolled out the Superpave system in 1993, but it took years for individual states and their paving contractors to switch to the new system, which represents a significant departure, not only in design, but also in the procedures and equipment used for testing. Each state DOT had to be convinced that the benefits would outweigh the modest additional costs of Superpave mixes, as well as the time and effort to train its staff and acquire necessary equipment.A survey in 2005 showed that 50 state DOTs (including the District of Columbia and Puerto Rico) were using Superpave (Figure 1). The remaining two states indicated that they would be doing so by the end of 2006. Throughout the implementation period, researchers continued to refine the system (e.g., using recycled asphalt pavements in the mix design [TRB, 2005]).It may be years before the cost benefits of Superpave can be quantified. A 1997 study by the Te xas Transportation Institute projected that, when fully implemented, Superpave’s annualized net savings over 20 years would approach $1.8 billion annually—approximately $500 million in direct savings to the public and $1.3 billion to highway users (Little et al., 1997).Moreover, analyses by individual states and cities have found that Superpave has dramatically improved performance with little or no increase in cost. Superpave is not only an example of a successful research program. It also demonstrates that a vigorous, sustained technology-transfer effort is often required for innovation in a decentralized sector, such as highway transportation.Prefabricated ComponentsThe offsite manufacturing of steel and other components of reinforced concrete for bridges and tunnels is nothing new. But the need for reconstructing or replacing heavily used highway facilities has increased the use of prefabricated components in startling ways. In some cases components are manufactured thousands of miles from the job site; in others, they are manufactured immediately adjacent to the site. Either way, we are rethinking how design and construction can be integrated.When the Texas Department of Transportation needed to replace 113 bridge spans on an elevated interstate highway in Houston, it found that the existing columns were reusable, but the bent caps (the horizontal connections between columns) had to be replaced. As an alternative to the conventional, time-consuming, cast-in-place approach, researchers at the University of Texas devised new methods of installing precast concrete bents. In this project, the precast bents cut construction time from 18 months to slightly more than 3 months (TRB, 2001).As part of a massive project to replace the San Francisco-Oakland Bay Bridge, the California Department of Transportation and the Bay Area Toll Authority had to replace a 350-foot, 10-lane section of a viaduct on Yerba Buena Island. In this case, the contractor, C.C. Myers, prefabricated the section immediately adjacent to the existing viaduct. The entire bridge was then shut down for the 2007 Labor Day weekend, while the existing viaduct was demolished and the new 6,500-ton segment was “rolled” into place (Figure 2). The entire operation was accomplished 11 hours ahead of schedule (B. Kahn, 2007).Probably the most extensive and stunning collection of prefabricated applications on a single project was on the Central Artery/Tunnel Project (“Big Dig”) in Boston. For the Ted Williams Tunnel, a dozen 325-foot-long steel tunnel sections were constructed in Baltimore, shipped to Boston, floated into place, and then submerged. However, for the section of the tunnel that runs beneath the Four Points Channel, which is part of the I-90 extension, bridge restrictions made this approach infeasible. Instead, a huge casting basin was constructed adjacent to the channel where 30- to 50-ton concrete tunnel sections were manufactured The basin was flooded and the sections winched into position with cables and then submerged.An even more complicated process was used to build the extension tunnel under existing railroad tracks, which had poor underlying soil conditions. Concrete and steel boxes were built at one end of the tunnel, then gradually pushed into place through soil that had been frozen using a network of brine-filled pipes (Vanderwarker, 2001).Specialty Portland Cement ConcretesNew generations of specialty concretes have improved one or more aspects of performance and allow for greater flexibility in highway design and construction. High-performance concrete typically has compressive strengths of at least 10,000 psi. Today, ultra-high-performance concretes with formulations that include silica fume, quartz flour, water reducers, and steel or organic fibers have even greater durability and compressive strengths up to 30,000 psi. These new concretes can enable construction with thinner sections and longer spans (M.S. Kahn, 2007).Latex-modified concrete overlays have been used for many years to extend the life of existing, deteriorating concrete bridge decks by the Virginia DOT, which pioneered the use of very early strength latex-modified concretes for this application. In high-traffic situations, the added costs of the concrete have been more than offset by savings in traffic-control costs and fewer delays for drivers (Sprinkel, 2006).When the air temperature dips below 40， costly insulation techniques must be used when pouring concrete for highway projects. By using commercially available admixtures that depress the freezing point of water, the U.S. Cold-Weather Research and Engineering Laboratory has developed new concrete formulations that retain their strength and durability at temperatures as low as 23?F. Compared to insulation techniques, this innovation has significantly decreased construction costs and extended the construction season in cold weather regions (Korhonen, 2004).As useful as these and other specialty concretes are, nanotechnology and nanoengineering techniques, which are still in their infancy, have the potential to make even more dramatic improvements in theperformance and cost of concrete.Waste and Recycled MaterialsHighway construction has a long history of using industrial waste and by-product materials. The motivations of the construction industry were simple—to help dispose of materials that are otherwise difficult to manage and to reduce the initial costs of highway construction. The challenge has been to use these materials in ways that do not compromise critical performance properties and that do not introduce substances that are potenti-ally harmful to people or the environment. At the same time, as concerns about sustainability have become more prominent in public thinking, the incentives to use by-product materials have increased. In addition, because the reconstruction and resurfacing of highways create their own waste, recycling these construction materials makes economic and environmental sense.Research and demonstration projects have generated many successful uses of by-product and recycled materials in ways that simultaneously meet performance, environmental, and economic objectives. For example, “crumb rubber” from old tires is increasingly being used as an additive in certain hot-mix asphalt pavement designs, and a number of patents have been issued related to the production and design of crumb rubber or asphalt rubber pavements (CDOT, 2003; Epps, 1994).Several states, notably California and Arizona, use asphalt rubber hot mix as an overlay for distressed flexible and rigid pavements and as a means of reducing highway noise. Materials derived from discarded tires have also been successfully used as lightweight fill for highway embankments and backfill for retaining walls, as well as for asphalt-based sealers and membranes (Epps, 1994; TRB, 2001).Fly ash, a residue from coal-burning power plants, and silica fume, a residue from metal-producing furnaces, are increasingly being used as additives to portland cement concrete. Fly-ash concretes can reduce alkali-silica reactions that lead to the premature deterioration of concrete (Lane, 2001), and silica fume is a component of the ultra-high-performance concrete described above.After many years of experimentation and trials, reclaimed asphalt pavement (RAP) is now routinely used in virtually all 50 states as a substitute for aggregate and a portion of the asphalt binder in hot-mix asphalt, including Superpave mixes. The reclaimed material typically constitutes 25 to 50 percent of the “new” mix (TFHRC, 1998). The National Asphalt Pavement Association estimates that 90 percent of the asphalt pavement removed each year is recycled and that approximately 125 millions tons of RAP are produced, with an annual savings of $300 million (North Central Superpave Center, 2004).Visualization, Global Positioning Systems, and Other New Tools For more than 20 years, highway engineers have used two-dimensional, computer-aided drafting and design (CADD) systems to accelerate the design process and reduce costs. The benefits of CADD systems have derived essentially from automating the conventional design process, with engineers doing more or less what they had done before, although much faster and with greater flexibility.New generations of three- and four-dimensional systems are introducing new ways of designing roads, as well as building them (Figure 4). For example, three-dimensional visualization techniques are clearly useful for engineers. But, perhaps more importantly, they have improved the communication of potential designs to affected communities and public officials; in fact, they represent an entirely new design paradigm. Four-dimensional systems help engineers and contractors analyze the constructability of proposed designs well in advance of actual constructionGlobal positioning systems are being used in surveying/layout, in automated guidance systems for earth-moving equipment, and for monitoring quantities. Other innovations include in situ temperature sensors coupled with data storage, transmission, and processing devices that provide onsite information about the maturity and strength of concrete as it cures (Hannon, 2007; Hixson, 2006).ConclusionThe examples described above suggest the wide range of exciting innovations in the design and construction of highways. These innovations address materials, roadway and bridge designs, design and construction methods, road safety, and a variety of environmental, community, and aesthetic concerns. Looking to the future, however, challenges to the U.S. highway system will be even more daunting—accommodating more traffic and higher loadings; reducing traffic disruptions during construction; meeting more stringent environmental, community, and safety requirements; and continuing pressure to reduce costs. Addressing these challenges will require a commitment to innovation and the research that supports innovation.中文翻译高速公路设计与施工：创新的挑战作者：小罗伯特·E·斯金纳研究方式的创新和进步正在改变着美国公路建设的方式。

土建专业毕业设计外文翻译--建筑的组成部分

毕业论文（设计）外文翻译Components of A Building and Tall Buildings1. AbstractMaterials and structural forms are combined to make up the various parts of a building, including the load-carrying frame, skin, floors, and partitions. The building also has mechanical and electrical systems, such as elevators, heating and cooling systems, and lighting systems. The superstructure is that part of a building above ground, and the substructure and foundation is that part of a building below ground.The skyscraper owes its existence to two developments of the 19th century: steel skeleton construction and the passenger elevator. Steel as a construction material dates from the introduction of the Bessemer converter in 1885.Gustave Eiffel (1832-1932) introduced steel construction in France. His designs for the Galerie des Machines and the Tower for the Paris Exposition of 1889 expressed the lightness of the steel framework. The Eiffel Tower, 984 feet (300 meters) high, was the tallest structure built by man and was not surpassed until 40 years later by a series of American skyscrapers.Elisha Otis installed the first elevator in a department store in New York in 1857.In 1889, Eiffel installed the first elevators on a grand scale in the Eiffel Tower, whose hydraulic elevators could transport 2,350 passengers to the summit every hour.2. Load-Carrying FrameUntil the late 19th century, the exterior walls of a building were used as bearing walls to support the floors. This construction is essentially a post and lintel type, and it is still used in frame construction for houses. Bearing-wall construction limited the height of building because of the enormous wall thickness required；for instance, the 16-story Monadnock Building built in the 1880’s in Chicago had walls 5 feet (1.5 meters) thick at the lower floors. In 1883, William Le Baron Jenney (1832-1907) supported floors on cast-iron columns to form a cage-like construction. Skeleton construction, consisting of steel beams and columns, was first used in 1889. As a consequence of skele ton construction, the enclosing walls become a “curtain wall” rather than serving a supporting function. Masonry was the curtain wall material until the 1930’s, when light metal and glass curtain walls were used. After the introduction of buildings continued to increase rapidly.All tall buildings were built with a skeleton of steel until World War Ⅱ. After the war, the shortage of steel and the improved quality of concrete led to tall building being built of reinforced concrete. Marina Tower (1962) in Chicago is the tallest concrete building in the United States；its height—588 feet (179 meters)—is exceeded by the 650-foot (198-meter) Post Office Tower in London and by other towers.A change in attitude about skyscraper construction has brought a return to the use of the bearing wall. In New York City, the Columbia Broadcasting System Building, designed by Eero Saarinen in 1962,has a perimeter wall consisting of 5-foot (1.5meter) wide concrete columns spaced 10 feet (3 meters) from column center to center. This perimeter wall, in effect, constitutes a bearing wall. One reason for this trend is that stiffness against the action of wind can be economically obtained by using the walls of the building as a tube；the World Trade Center building is another example of this tube approach. In contrast, rigid frames or vertical trusses are usually provided to give lateral stability.3. SkinThe skin of a building consists of both transparent elements (windows) and opaque elements (walls). Windows are traditionally glass, although plastics are being used, especially in schools where breakage creates a maintenance problem. The wall elements, which are used to cover the structure and are supported by it, are built of a variety of materials: brick, precast concrete, stone, opaque glass, plastics, steel, and aluminum. Wood is used mainly in house construction；it is not generally used for commercial, industrial, or public building because of the fire hazard.4. FloorsThe construction of the floors in a building depends on the basic structural frame that is used. In steel skeleton construction, floors are either slabs of concrete resting on steel beams or a deck consisting of corrugated steel with a concrete topping. In concrete construction, the floors are either slabs of concrete on concrete beams or a series of closely spaced concrete beams (ribs) in two directions topped with a thin concrete slab, giving the appearance of a waffle on its underside. The kind of floor that is used depends on the span between supporting column s or walls and the function of the space. In an apartment building, for instance, where walls and columns are spaced at 12 to 18 feet (3.7 to 5.5 meters), the most popular construction is a solid concrete slab with no beams. The underside of the slab serves as the ceiling for the space below it. Corrugated steel decks are often used in office buildings because the corrugations, when enclosed by another sheet of metal, form ducts for telephone and electrical lines.5. Mechanical and Electrical SystemsA modern building not only contains the space for which it is intended (office, classroom, apartment) but also contains ancillary space for mechanical and electrical systems that help to provide a comfortable environment. These ancillary spaces in a skyscraper o ffice building may constitute 25% of the total building area. The importance of heating, ventilating, electrical, and plumbing systems in an office building is shown by the fact that 40% of the construction budget is allocated to them. Because of the increased use of sealed building with windows that cannot be opened, elaborate mechanical systems are provided for ventilation and air conditioning. Ducts and pipes carry fresh air from central fan rooms and air conditioning machinery. The ceiling, which issuspended below the upper floor construction, conceals the ductwork and contains the lighting units. Electrical wiring for power and for telephone communication may also be located in this ceiling space or may be buried in the floor construction in pipes or conduits.There have been attempts to incorporate the mechanical and electrical systems into the architecture of building by frankly expressing them；for example, the American Republic Insurance Company Building(1965) in Des Moines, Iowa, exposes both the ducts and the floor structure in an organized and elegant pattern and dispenses with the suspended ceiling. This type of approach makes it possible to reduce the cost of the building and permits innovations, such as in the span of the structure.6. Soils and FoundationsAll building are supported on the ground, and therefore the nature of the soil becomes an extremely important consideration in the design of any building. The design of a foundation depends on many soil factors, such as type of soil, soil stratification, thickness of soil lavers and their compaction, and groundwater conditions. Soils rarely have a single composition；they generally are mixtures in layers of varying thickness. For evaluation, soils are graded according to particle size, which increases from silt to clay to sand to gravel to rock. In general, the larger particle soils will support heavier loads than the smaller ones. The hardest rock can support loads up to 100 tons per square foot(976.5 metric tons/sq meter), but the softest silt can support a load of only 0.25 ton per square foot(2.44 metric tons/sq meter). All soils beneath the surface are in a state of compaction；that is, they are under a pressure that is equal to the weight of the soil column above it. Many soils (except for most sands and gavels) exhibit elastic properties—they deform when compressed under load and rebound when the load is removed. The elasticity of soils is often time-dependent, that is, deformations of the soil occur over a length of time which may vary from minutes to years after a load is imposed. Over a period of time, a building may settle if it imposes a load on the soil greater than the natural compaction weight of the soil. Conversely, a building may heave if it imposes loads on the soil smaller than the natural compaction weight. The soil may also flow under the weight of a building；that is, it tends to be squeezed out.Due to both the compaction and flow effects, buildings tend settle. Uneven settlements, exemplified by the leaning towers in Pisa and Bologna, can have damaging effects—the building may lean, walls and partitions may crack, windows and doors may become inoperative, and, in the extreme, a building may collapse. Uniform settlements are not so serious, although extreme conditions, such as those in Mexico City, can have serious consequences. Over the past 100 years, a change in the groundwater level there has caused some buildings to settle more than 10 feet (3 meters). Because such movements can occur during and after construction, careful analysis of the behavior of soils under a building is vital.The great variability of soils has led to a variety of solutions to the foundation problem. Wherefirm soil exists close to the surface, the simplest solution is to rest columns on a small sl ab of concrete(spread footing). Where the soil is softer, it is necessary to spread the column load over a greater area；in this case, a continuous slab of concrete(raft or mat) under the whole building is used. In cases where the soil near the surface is unable to support the weight of the building, piles of wood, steel, or concrete are driven down to firm soil.The construction of a building proceeds naturally from the foundation up to the superstructure. The design process, however, proceeds from the roof down to the foundation (in the direction of gravity). In the past, the foundation was not subject to systematic investigation. A scientific approach to the design of foundations has been developed in the 20th century. Karl Terzaghi of the United States pioneered studies that made it possible to make accurate predictions of the behavior of foundations, using the science of soil mechanics coupled with exploration and testing procedures. Foundation failures of the past, such as the classical example of the l eaning tower in Pisa, have become almost nonexistent. Foundations still are a hidden but costly part of many buildings.Although there have been many advancements in building construction technology in general, spectacular achievements have been made in the design and construction of ultrahigh-rise buildings.The early development of high-rise buildings began with structural steel framing. Reinforced concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes. The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structural systems.Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit. Excessive lateral sway may cause serious recurring damage to partitions, ceilings, and other architectural details. In addit ion, excessive sway may cause discomfort to the occupants of the building because of their perception of such motion. Structural systems of reinforced concrete, as well as steel, take full advantage of the inherent potential stiffness of the total building and therefore do not require additional stiffening to limit the sway.In a steel structure, for example, the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building. Curve A in Fig.1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B represents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame. Structural engineers have developed structural systems with a view to eliminating this premium.7. Tube in tubeAnother system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system (Fig.2), known as the tube-in-tube system, made it possible to design the world’s present tallest (714 ft or 218 m) lightweight concrete building (the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.Systems combining both concrete and steel have also been developed, an example of which is the composite system developed by Skidmore, Owings & Merrill in which an exterior closel y spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The story One Shell Square Building in New Orleans is based on this system.建筑的组成部分1 摘要材料和结构类型是构成建筑物各方面的组成部分，包括承重结构、围护结构、楼地面和隔墙。

公路专业英语作文模板

公路专业英语作文模板英文回答：Highway Engineering。

Highway engineering is a branch of civil engineering that deals with the planning, design, construction, and maintenance of roads. Roads are essential for transportation, and they play a vital role in the economic and social development of a country.Highway engineers are responsible for ensuring that roads are safe, efficient, and durable. They must take into account a variety of factors when designing a road, including traffic volume, traffic speed, road geometry, and environmental conditions.The planning phase of a highway project involves identifying the need for a new road or the improvement of an existing road. Engineers must study traffic patterns andpopulation growth to estimate the future demand for transportation. They must also identify potential environmental impacts and develop plans to mitigate those impacts.The design phase of a highway project involves developing detailed plans for the road, including the alignment, grade, pavement type, and drainage system. Engineers must use computer software to model the road and analyze its performance under different traffic conditions.The construction phase of a highway project involves building the road according to the design plans. Engineers must oversee the work of contractors and ensure that the road is built to the required standards.The maintenance phase of a highway project involves keeping the road in good condition. Engineers must inspect the road regularly and perform repairs as needed. They must also monitor traffic patterns and make adjustments to the road as needed to improve safety and efficiency.Highway engineering is a complex and challenging field, but it is also a rewarding one. Highway engineers play a vital role in the development of our transportation system, and they help to make our roads safe, efficient, and durable.中文回答：公路工程。

土木工程-毕业设计-论文-外文翻译-中英文对照

英文原文：Concrete structure reinforcement designSheyanb oⅠWangchenji aⅡⅠFoundation Engineering Co., Ltd. Heilongjiang DongyuⅡHeilongjiang Province, East Building Foundation Engineering Co., Ltd. CoalAbstract：structure in the long-term natural environment and under the use environment's function, its function is weaken inevitably gradually, our structural engineering's duty not just must finish the building earlier period the project work, but must be able the science appraisal structure damage objective law and the degree, and adopts the effective method guarantee structure the security use, that the structure reinforcement will become an important work. What may foresee will be the 21st century, the human building also by the concrete structure, the steel structure, the bricking-up structure and so on primarily, the present stage I will think us in the structure reinforcement this aspect research should also take this as the main breakthrough direction.Key word：Concrete structure reinforcement bricking-up structure reinforcement steel structure reinforcement1 Concrete structure reinforcementConcrete structure's reinforcement divides into the direct reinforcement and reinforces two kinds indirectly, when the design may act according to the actual condition and the operation requirements choice being suitable method and the necessary technology.1.1the direct reinforcement's general method1）Enlarges the section reinforcement lawAdds the concretes cast-in-place level in the reinforced concrete member in bending compression zone, may increase the section effective height, the expansion cross sectional area, thus enhances the component right section anti-curved, the oblique section anti-cuts ability and the section rigidity, plays the reinforcement reinforcement the role.In the suitable muscle scope, the concretes change curved the component right section supporting capacity increase along with the area of reinforcement and the intensity enhance. In the original component right section ratio of reinforcement not too high situation, increases the main reinforcement area to be possible to propose the plateau component right section anti-curved supporting capacity effectively. Is pulled in the section the area to add the cast-in-place concrete jacket to increase the component section, through new Canada partial and original component joint work, but enhances the component supporting capacity effectively, improvement normal operational performance.Enlarges the section reinforcement law construction craft simply, compatible, and has the mature design and the construction experience; Is suitable in Liang, the board, the column, the wall and the general structure concretes reinforcement; But scene construction's wet operating time is long, to produces has certain influence with the life, and after reinforcing the building clearance has certain reduction.2) Replacement concretes reinforcement lawThis law's merit with enlarges the method of sections to be close, and after reinforcing, does not affect building's clearance, but similar existence construction wet operating time long shortcoming; Is suitable somewhat low or has concretes carrier's and so on serious defect Liang, column in the compression zone concretes intensity reinforcement.3) the caking outsourcing section reinforcement lawOutside the Baotou Steel Factory reinforcement is wraps in the section or the steel plate is reinforced component's outside, outside the Baotou Steel Factory reinforces reinforced concrete Liang to use the wet outsourcing law generally, namely uses the epoxy resinification to be in the milk and so on methods with to reinforce the section the construction commission to cake a whole, after the reinforcement component, because is pulled with the compressed steel cross sectional area large scale enhancement, therefore right section supporting capacity and section rigidity large scale enhancement.This law also said that the wet outside Baotou Steel Factory reinforcement law, the stress is reliable, the construction is simple, the scene work load is small, but is big with the steel quantity, and uses in above not suitably 600C in the non-protection's situation the high temperature place; Is suitable does not allow in the use obviously to increase the original component section size, but requests to sharpen its bearing capacity large scale the concrete structure reinforcement.4) Sticks the steel reinforcement lawOutside the reinforced concrete member in bending sticks the steel reinforcement is (right section is pulled in the component supporting capacity insufficient sector area, right section compression zone or oblique section) the superficial glue steel plate, like this may enhance is reinforced component's supporting capacity, and constructs conveniently.This law construction is fast, the scene not wet work or only has the plastering and so on few wet works, to produces is small with the life influence, and after reinforcing, is not remarkable to the original structure outward appearance and the original clearance affects, but the reinforcement effect is decided to a great extent by the gummy craft and the operational level; Is suitable in the withstanding static function, and is in the normal humidity environment to bend or the tension member reinforcement.5) Glue fibre reinforcement plastic reinforcement lawOutside pastes the textile fiber reinforcement is pastes with the cementing material the fibre reinforcement compound materials in is reinforced the component to pull the region, causes it with to reinforce the section joint work, achieves sharpens the component bearing capacity the goal. Besides has glues the steel plate similar merit, but also has anticorrosive muddy, bears moistly, does not increase the self-weight of structure nearly, durably, the maintenance cost low status merit, but needs special fire protection processing, is suitable in each kind of stress nature concrete structure component and the general construction.This law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.6) Reeling lawThis law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.7) Fang bolt anchor lawThis law is suitable in the concretes intensity rank is the C20~C60 concretes load-bearing member transformation, the reinforcement; It is not suitable for already the above structure which and the light quality structure makes decent seriously. 1.2The indirect reinforcement's general method1)Pre-stressed reinforcement law(1)Thepre-stressed horizontal tension bar reinforces concretes member in bending,because the pre-stressed and increases the exterior load the combined action, in the tension bar has the axial tension, this strength eccentric transmits on the component through the pole end anchor (, when tension bar and Liang board bottom surface close fitting, tension bar can look for tune together with component, this fashion has partial pressures to transmit directly for component bottom surface), has the eccentric compression function in the component, this function has overcome the bending moment which outside the part the load produces, reduced outside the load effect, thus sharpened component's anti-curved ability. At the same time, because the tension bar passes to component's pressure function, the component crack development can alleviate, the control, the oblique section anti-to cut the supporting capacity also along with it enhancement.As a result of the horizontal lifting stem's function, the original component's section stress characteristic by received bends turned the eccentric compression, therefore, after the reinforcement, component's supporting capacity was mainly decided in bends under the condition the original component's supporting capacity 。

毕业设计论文外文文献翻译

xxxx大学xxx学院毕业设计（论文）外文文献翻译系部xxxx专业xxxx学生姓名xxxx 学号xxxx指导教师xxxx 职称xxxx2013年3 月Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory” lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole worldview on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution for all middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container.It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that can be used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classesfor O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlying O/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remote services without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is inc luded for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entireconfiguration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (and relevant even in a book on “J2EE without EJB”) because the u se of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice.Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transactioncoordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is also popular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in the WEB-INF directory, containing bean defini-tions according to the “spring-beans” DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource” bean, a “myInventoryManager” bean, and a “myProductManager” bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource” class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager” class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager” class=”ebusiness.DefaultProductManage r”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton” scope: one instance per context. The “myInventoryManager” bean will automatically be wired up with the defined DataSource, while “myProductManager” will in turn receive a reference to the “myInventoryManager” bean. Those objects (traditionally called “beans” in Spring terminology) need to expos e only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener>...</web-app>After initialization of the web app, the root web application context will be available as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web. context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasive application framework.Fundamental InterfacesThe fundamental lightweight container interface is org.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not foundin the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be used stan-dalone if no other Spring services are required.Derivative：networkSpring 框架简介Spring框架：这是一个流行的开源应用框架，它可以解决很多问题。

道路工程(路桥)毕业设计外文文献翻译

外文文献翻译原文：Asphalt Mixtures-Applications, Theory and Principles1 . ApplicationsAsphalt materials find wide usage in the construction industry. The use of asphalt as a cementing agent in pavements is the most common of its applications, however, and the one that will be consid ered here.Asphalt products are used to produce flexibl e pavements for highways and airports. The term “fl exible” is used to distinguish these pavements from those made with Portland cement, which are classified as rigid pavements, that is, having beam strength. This distinction is important because it provid es they key to the design approach which must be used for successful flexibl e pavement structures.The flexibl e pavement classification may be further broken d own into high and l ow types, the type usually depending on whether a solid or liquid asphalt product is used. The l ow types of pavement are mad e with the cutback, or emulsion, liquid products and are very widely used throughout this country. Descriptive terminology has been devel oped in various sections of the country to the extent that one pavement type may have several names. However, the general process foll owed in construction is similar for most l ow-type pavements and can be described as one in which the aggregate and the asphalt product are usually applied to the roadbed separately and there mixed or all owed to mix, forming the pavement.The high type of asphalt pavements is made with asphalt cements of some sel ected penetration grad e.Fig. ·1 A modern asphalt concrete highway. Should er striping is used as a safely feature.Fig. ·2 Asphalt concrete at the San Francisco International Airport.They are used when high wheel l oads and high volumes of traffic occur and are, therefore, often designed for a particular installation.2 . Theory of asphalt concrete mix designHigh types of flexible pavement are constructed by combining an asphalt cement, often in the penetration grad e of 85 to 100, with aggregates that are usually divided into three groups, based on size. The three groups are coarse aggregates, fine aggregates, and mineral filler. These will be discussed in d etail in later chapter.Each of the constituent parts mentioned has a particular function in the asphalt mixture, and mix proportioning or d esign is the process of ensuring that no function is negl ected. Before these individual functions are examined, however, the criteria for pavement success and failure should be consid ered so that d esign objectives can be established.A successful fl exible pavement must have several particular properties. First, it must be stable, that is to resistant to permanent displacement under l oad. Deformation of an asphalt pavement can occur in three ways, two unsatisfactory and one desirable. Plastic d eformationof a pavement failure and which is to be avoid ed if possible. Compressive deformation of the pavement results in a dimensional change in the pavement, and with this change come a l oss of resiliency and usually a d egree of roughness. This deformation is less serious than the one just described, but it, too, leads to pavement failure. The desirabl e type of deformation is an elastic one, which actually is beneficial to flexibl e pavements and is necessary to their long life.The pavement should be durable and should offer protection to the subgrade. Asphalt cement is not impervious to the effects of weathering, and so the design must minimize weather susceptibility. A durable pavement that does not crack or ravel will probably also protect the roadbed. It must be remembered that fl exible pavements transmit l oads to the subgrad e without significant bridging action, and so a dry firm base is absolutely essential.Rapidly moving vehicl es d epend on the tire-pavement friction factor for control and safety. The texture of the pavement surfaces must be such that an adequate skid resistance is developed or unsafe conditions result. The design procedure should be used to sel ect the asphalt material and aggregates combination which provid es a skid resistant roadway.Design procedures which yield paving mixtures embodying all these properties are not available. Sound pavements are constructed where materials and methods are selected by using time-tested tests and specifications and engineering judgments al ong with a so-call ed design method.The final requirement for any pavement is one of economy. Economy, again, cannot be measured directly, since true economy only begins with construction cost and is not fully determinable until the full useful life of the pavement has been record ed. If, however, the requirements for a stable, durable, and safe pavement are met with a reasonable safety factor, then the best interests of economy have probably been served as well.With these requirements in mind, the functions of the constituent parts can be examined with consideration give to how each part contributes to now-established objectives or requirements. The functions of the aggregates is to carry the l oad imposed on the pavement, and this is accomplished by frictional resistance and interl ocking between the individual pieces of aggregates. The carrying capacity of the asphalt pavement is, then, related to the surface texture (particularly that of the fine aggregate) and the density, or “compactness,”, of the aggregates. Surface texture varies with different aggregates, and while a rough surfacetexture is desired, this may not be available in some l ocalities. Dense mixtures are obtained by using aggregates that are either naturally or artificially “well grad ed”. This means that the fine aggregate serves to fill the voids in the coarser aggregates. In addition to affecting density and therefore strength characteristics, the grading also influences workability. When an excess of coarse aggregate is used, the mix becomes harsh and hard to work. When an excess of mineral filler is used, the mixes become gummy and difficult to manage.The asphalt cement in the fl exibl e pavement is used to bind the aggregate particl es together and to waterproof the pavements. Obtaining the proper asphalt content is extremely important and bears a significant influence on all the items marking a successful pavement. A chief objective of all the design methods which have been devel oped is to arrive at the best asphalt content for a particular combination of aggregates.3 . Mix design principl esCertain fundamental principles underlie the design procedures that have been developed. Before these procedures can be properly studied or applied, some consid eration of these principles is necessary.Asphalt pavements are composed of aggregates, asphalt cement, and voids. Consid ering the aggregate alone, all the space between particles is void space. The volume of aggregate voids depends on grading and can vary widely. When the asphalt cement is ad ded, a portion of these aggregate voids is fill ed and a final air-void volume is retained. The retention of thisair-void volume is very important to the characteristics of the mixture. The term air-void volume is used, since these voids are weightless and are usually expressed as a percentage of the total volume of the compacted mixture.An asphalt pavement carries the applied load by particl e friction and interlock. If the particl es are pushed apart for any reason , then the pavement stability is d estroyed. This factor indicates that certainly no more asphalt shoul d be ad ded than the aggregate voids can readily hold. However ,asphalt cement is susceptible to volume change and the pavement is subject to further compaction under use. If the pavement has no air voids when placed, or if it loses them under traffic, then the expanding asphalt will overfl ow in a condition known as bleeding. The l oss of asphalt cement through bl eeding weakens the pavement and also reduces surface friction, making the roadway hazard ous.Fig. ·3 Cross section of an asphalt concrete pavement showing the aggregate framework bound together by asphalt cement.The need for a minimum air-void volume (usually 2 or 3 per cent ) has been established. In addition, a maximum air-void volume of 5 to 7 per cent shoul d not be exceed. An excess of air voids promotes raveling of the pavement and also permits water to enter and speed up the deteriorating processes. Also, in the presence of excess air the asphalt cement hard ens and ages with an accompanying loss of durability and resiliency.The air-void volume of the mix is determined by the d egree of compaction as well as by the asphalt content. For a given asphalt content, a lightly compacted mix will have a large voids volume and a l ower d ensity and a greater strength will result. In the laboratory, the compaction is controlled by using a specified hammer and regulating the number of bl ows and the energy per blow. In the fiel d, the compaction and the air voids are more difficult to control and tests must be made no specimens taken from the compacted pavement to cheek on the d egree of compaction being obtained. Traffic further compact the pavement, andall owance must be mad e for this in the design. A systematic checking of the pavement over an extend ed period is needed to given factual information for a particular mix. A change in density of several per cent is not unusual, however.Asphalt content has been discussed in connection with various facets of the ix design problem. It is a very important factor in the mix design and has a bearing an all the characteristics ld a successful pavement: stability, skid resistance, durability, and economy. As has been mentioned, the various design procedures are intended to provid e a means for selecting the asphalt content . These tests will be consid ered in detail in a future chapter ,butthe relationship between asphalt content and the measurable properties of stability, unit weight, and air voids will be discussed here.Fig.4 Variations in stability, unit weight, and air-void content with asphalt cement content.If the gradation and type of aggregate, the degree of compaction, and the type of asphalt cement are controll ed, then the strength varies in a predictable manner. The strength will increase up to some optimum asphalt content and then decrease with further additions. The pattern of strength variation will be different when the other mix factors are changed, and so only a typical pattern can be predicted prior to actual testing.Unit weight varies in the same manner as strength when all other variabl e are controll ed. It will reach some peak value at an asphalt content near that determined from the strength curve and then fall off with further additions.As already mentioned, the air-void volume will vary with asphalt content. However, the manner of variation is different in that increased asphalt content will d ecrease air-void volume to some minimum value which is approached asymptotically. With still greater additions of asphalt material the particles of aggregate are only pushed apart and no change occurs in air-void volume.In summary, certain principles involving aggregate gradation, air-void volume, asphalt content, and compaction mist be understood before proceeding to actual mix d esign. The proper design based on these principl es will result in sound pavements. If these principles are overl ooked, the pavement may fail by one or more of the recognized modes of failure: shoving, rutting, corrugating, becoming slick when the max is too ‘rich’; raveling, cracking, having low durability whe n the mix is too ‘l ean’.It should be again emphasized that the strength of flexible is, more accurately, a stabilityand d oes not indicate any ability to bridge weak points in the subgrade by beam strength. No asphalt mixture can be successful unless it rests on top of a properly designed and constructed base structure. This fact, that the surface is no better than the base, must be continually in the minds of those concerned with any aspect of fl exible pavement work.译文：沥青混合料的应用、理论和原则1、应用沥青材料如今在建筑行业广泛使用。

毕业设计英文翻译(原文)

编号：毕业设计(论文)外文翻译（原文）院（系）：桂林电子科技大学专业：电子信息工程学生姓名： xx学号： xxxxxxxxxxxxx 指导教师单位：桂林电子科技大学姓名： xxxx职称： xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。