土木工程橋梁方向畢業(yè)設(shè)計(jì)外文及翻譯

1、畢業(yè)設(shè)計(jì)（論文）資料附件:外文文獻(xiàn)原文及譯文t=r.號:級:學(xué)生姓名: 學(xué) 班專業(yè):十木工程（橋梁方向）指導(dǎo)教師:2010年3月What is traffic engineeringTraffic engineering is still a relatively new discipline within the overall bounds of civil engineering. it has nevertheless already been partially planning. the disciplines are not synonymous though. transpor

2、tation planning is concerned with the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, rapid, comfortable, convenient, economical and enviromenally-comparible movement of people and goods. within that broad scope, tr

3、affic engineering deals with those functions in respect of roads, road networks, terminal points , about lands and their relationships with other modes of transportation.Those definitions, based on the 1976 ones of the U.S.institute of transportation engineers are complete than, the British institut

4、ing of civil engineering which deals with traffic planning and design of roads, of frontage development and of parking facilities and with the control of traffic to provide safe, convenient and economical movement of vehicles and pedestrians.The definitions of the disicipline are becoming clearer: t

5、he methodology is developing continuously and becoming increasingly scientific. the early rule-of-thumb techniques are disappearing.Traffic problemThe discipline is young: the problem is large and still growing. in 1920 the total number of motor vehicles, licensed in great Britain was,650,000.fifty

6、year later the comparable figure was 14,950,000-a growth factor of 23 times. in recent years the rate of growth has slackened somewhat, but it is still considerable:19556,466,00019609,439,000196512,938,000197014,950,000197417,247,000In order to see the problem in every day terms ,consider high stree

7、t. anywhere. assuming that present trends continue, it is expected that within the next fifteen years of so the traffic on this road will increase by around forty to fifty persent. if this increased volume of traffic were to be accommodated at thesame standard as today, the road might need to be wid

8、ened by a similar forty to fifty percent-perhaps extra lane of traffic for the pedestrian to cross. In man cases, to accommodate the foreseeable future demand would destroy the character of the whole urban environment, and is clearly unacceptable.the traffic problem is of world-wide concern, but dif

9、ferent countries are obviously at different stagesin the traffic escalation-with America in the lead, while a county has few roads and a relatively low problem, as soon as the country is opened up by a road system, the standard of living and the demand for motor transport both rise, gathering moment

10、um rapidly. eventually-and the stage at which this happens is open to considerable debate-the demand for cars, buses and lorries become satiated. the stage is known as saturation level.For comparison ,car ownership figures in different countries in 1970 were:India0.01 cars/personIsrael0.05cars/perso

11、nJapan0.09 cars/personIreland0.13 cars/personNetherlands0.20 cars/personGreat Britain0.21 cars/personWest Germany0.23 cars/personAustralia0.31 cars/personUSA0.44 cars/personin vehicle ownership is only part of the overall trafficBut the growth problem. obviously,if a country has unlimited roads of e

12、xtreme width, the traffic problem would not rise. no country in the world could meet this requirement: apart from anything else, it would not make economic for each vehicle using the roads. This figure is decreasing steadily.Three possible solutionsThe basic problem of traffic is therefore simple-an

13、 ever-increasing number of vehicles seeking to use too little roade space. the solution to the problem-is else a not-too-difficult choice from three possiblilities:build, sufficient roads of sufficient size to cope with the demand.Restrict the demand for roads by restricting the numbers of licensed

14、vehicles.A compromise between (a) and (b) build some extra roads, using the and the existing road network to their full potential, and at the same time apply some restraint measures, limiting, the increase in demand as far as possible.With no visible end to the demand yet in sight, and 216 with mode

15、rn road-making costs ranging around £ 1 million per kilometer cost of building roads in Britain to cope with an unrestricted demand would be far too great. added to this, such clossal use of space in a crowed island cannot be, seriously considered. in Los Angeles, a city built around the parkin

16、g space for, the automobile. our citie are already largely built-and no one would consider ruining their character by pulling them down and rebuilding around the car, thus the first possible soluting is rule out.Even today,in an age of at least semi-affluence in most of the Western World, the car is

17、 still to some extent a status symbol, a symbol of prestige.every family wants to own one, and takes steps saving or borrowing-to get one. as incomes and standards rise the second car becomes the target. any move to restrict the acquisition of the private car would be most unpopular-and politically

18、unlikely.For many purpose the flexibility of the private car-conceptually affording door-to-door personal transport is ideal, and its use can be accommodate. for the mass, movement of people along specific corridors within a limited period of time-i.e. particularly the journey to work it may be less

19、 easily accommodated. other transport mode may be more efficient. some sort of compromise solution is the inevitable answer to the basic traffic problem .it is in the execution of the compromise solution that, traffic engineering comes into its own. traffic engineering ensures that any new facilitie

20、s are not over-deigned and are correctly located to meet the demand. it ensures that the existing facilities are fully used, in the most efficient manner. the fulfillment of these duties may entail the selective throttling of demand: making the use of the car less attractive in the peak periods in o

21、rder that the limited road space can be more efficiently used by public transport.Such restraint measures will often be accompanied by improvements in the public transport services, to accommodate the extra demand for them.Prestressed Concrete BridgesPrestressed concrete has been used extensively in

22、 U.S. bridge construction since its first Introduction from Europe in the late 1940s. Literally thousands of highway bridges of both precast, prestressed concrete and cast-in-place post-tensioned concrete has beenconstructed in the United States. Railroad bridges utilizing prastressedconcrete have b

23、ecome common as well. The use and evolution of prastressed concrete bridges is expected to continue in the years ahead.Short-span BridgesShort-span bridges will be assumed to have a maximum of 45 ft (13.7m).It should be understood that this is an arbitrary figure, and there is no definite line of de

24、marcation between short, moderate, and long spans in highway bridges. Short-span bridges are most efficiently made of precast ,prestressed-concrete hollow slabs, I-beams, solid slabs or cast-place solid slabs. and T-beams of relatively generous proportions.Precast solid slabs are most economical whe

25、n used on very short spans. The slabs can be made in any convenient width,but widths of 3 or 4 ft (0.9 to 1.2m) have been common.Keys frequently are cast in the longitudinal sides of the precast units. After the slabs have been erected and the joints between the slabs have been filled with concrete,

26、 the keys transfer live load shear forces between the adjacent slabs.Precast hollow slabs used in short-span bridges may have round or square voids. They too are generally made in units 3 to 4 ft (0.9 to 1.2 m) wide with thicknesses from 18 to 27 in (45.7 to 68.6cm). Precast hollow slabs can be made

27、 in any convenient width and depth, and frequently are used in bridges having spans from 20 to 50 ft (6.1 to 15.2m). Longitudinal shear keys are used in the joints between adjacent hollow slabs in the same way as with solid slabs. Hollow slabs may or may not be used with a composite, cast-in-place c

28、oncrete topping an accecptable appearance and levelness.Transverse reinforcement normally is provided in precast concrete bridge superstructuresfor the purpose of tying the structure together in the transverse direction. Well-designed ties ensure that the individual longitudinal membersformingthe su

29、perstructure will act as a unit under the effects of the live load. In slab bridge construction, transverse ties most frequently consist of threaded steel bars placed through small holes formed transversely through the member during fabrication. Nuts frequently are used as fasteners at each end of t

30、he bars. In some instances,the transverse ties consist of post tensioned tendons placed, stressed, and grouted after the slabs have been erected. The transverse tie usually extends from one side of the bridge to the other.The shear forces imposed on the stringers in short-span bridges frequently are

31、 too large to be resisted by the concrete alone. Hence, shear reinforcement normally is required. The amount of shear reinforcement required may be relatively large if the webs of the stringers are relatively thin.Concrete diaphragms, reinforced with post-tensioned reinforcement or nonprestressed re

32、inforcement, normally are provided transversely at the ends and at intermediate locations along the span in stringer-type bridges. The disaphragms ensure the lateral-distribution of the live load to the various stringers and prevent individual stringers from displacing or rotating significantly with

33、 respect to the adjacent stringers.No generalities will be made here about the relative cost of each of the above types of construction; construction costs are a function of many variables which prohibit meaningful generalizations. However, it should be noted that the stringer type of construction r

34、equires a considerably greater construction depth that is required for solid, hollow, or channel slab bridge superstructures. Stringer construction does not require a separate wearing surface, as do the precastslab types of construction, unless precast slabs are used to span between the stringers in

35、 lieu of the more commonly used cast-in-place reinforced concrete deck. Stringer construction frequently requires smaller quantities of superstructure materials than do slab bridges (unless the spans are very short). The construction time needed to complete a bridge after the precast members have be

36、en erected is greater with stringer framing than with the slab type of framing.Bridges Of Moderate SpanAgain for the purpose of this discussion only, moderate spans for bridges of prestressedconcrete are defined as being from 45 to 80 ft (13.7 to 24.4m). Prestressed concrete bridges in this span ran

37、ge generally can be divided into two types: stringer-type bridges and slab-type bridges. The majority of the precast prestressed concrete bridges constructed in the United States have been stringer bridges using I-shaped stringers, but a large number of precast prestressed concrete bridges have been

38、 constructed with precast hollow-box girders (sometimes also called stringers). Cast-in-place post-tensioned concrete has been used extensively in the construction of hollow-box girder bridges-a form of construction that can be considered to be a slab bridge.Stringer bridges, which employ a composit

39、e, cast-in-place deck slab, have been used in virtually all parts of the United States. These stringers normally are used at spacing s of about 5 to 6 ft (1.5 to 1.8m). The cast-in-place deck is generally from 6.0 to 8.0 in(15.2 to 20.3cm) in thickness. This type of framing is very much the same as

40、that used on composite-stringer construction for short-span bridges.Diaphram details in moderate-span bridges are generally similar to those of the short spans, with the exception that two or three interior diaphragms sometime are used, rather than just one at midspan as in the short-span bridge.As

41、in the case of short-span bridges, the minimum depth of construction in bridges of moderate span is obtained by using slab construction, which may be either solid -or hollow -box in cross sect ion. Average con struct ion dep ths are requires when stringers with large flanges are used in composite co

42、nstruction, and large construction depths are required when stringers with small bottom flanges are used. Composite construction may be developed through the use of cast-in-place concrete decks or with precast concrete decks. Lower quantities of materials normally are required with composite constru

43、ction , and the dead weight of the superstructure normally is less for stringer construction than for slab construction.Long-Span BridgesPrestressed concrete bridges having spans of the order of 100ft are of the same general types of construction as structures having moderate span lengths, with the

44、single exception that solid slabs are not used for long spans. The stringer spacings are frequently greater (with stringers at 7 to 9 ft) as the span lengths of bridges increase. Because of dead weight considerations, precast hollow-box construction generally is employed for spans of this length onl

45、y when the depth of construction must be minimized. Cast-in-place post-tensioned hollow-box bridges with simple and continuous spans frequently are used for spans on the order of 100 ft and longer.Simple, precast, prestressed stringer construction would be economical in the United States in the span

46、s up to 300 ft under some conditions. However, only limited use has been made of this type of construction on spans greater than 100 ft. For very long simple spans, the advantage of precasting frequently is nullified by the difficulties involved in handling, transporting, and erecing the girders, wh

47、ich may have depths as great as 10 ft and weigh over 200 tons. The exceptions to this occur on large projects where all of the spans are over water of sufficient depth and character that precast beams can be handled with floating equipment, when custom girder launchers can be used, and when segmenta

48、l construction techniques can be used.The use of cast-in-place , post-tensioned, box-girder bridges has been extensive. Although structures of these types occasionally are used for spans less than 100ft, they more often are used for spans in excess of 100 ft and have been used in structuresHaving sp

49、ans in excess of 300 ft. Structurally efficient in flexure, especially for continuous bridges, the box girder is torsionally stiff and hence an excellent type of structure for use on bridges that have horizontal curvature. Some governmental agencies use this form of construction almost exclusively i

50、n urban areas where appearance from underneath the superstructure, as well as from the side, is considered important.交通工程介紹什么是交通工程交通工程仍然是在土木工程的總的界限內(nèi)的一種相對新的訓(xùn)練。雖然如 此交通工程已經(jīng)部分計(jì)劃 .可是，訓(xùn)練不同義。 計(jì)劃的運(yùn)輸涉及計(jì)劃， 功能的 設(shè)計(jì)，為運(yùn)輸?shù)娜魏畏绞绞炀毜慕?jīng)營管理， 為了為人和貨物的安全，迅速， 舒適，方便，節(jié)約和環(huán)境運(yùn)動作準(zhǔn)備。在那寬的范圍內(nèi)， 交通工程關(guān)于道 路，道路網(wǎng)絡(luò)，端子點(diǎn)，關(guān)于土地和他們的有運(yùn)輸?shù)钠渌绞降年P(guān)系處

51、理那 些功能。那些定義，那些定義， 基于那些美國研究院的 1976 個(gè)工程師完整 的運(yùn)輸比較英國土木工程的設(shè)立， 處理計(jì)劃的交通和道路的設(shè)計(jì)， 空地發(fā) 展和停放設(shè)備并且與一起要提供安全， 方便和節(jié)約運(yùn)動的車輛和行人的掌握 的交通。那些訓(xùn)練的定義變得清楚：那些方法學(xué)連續(xù)發(fā)展并且變得越來越科 學(xué)。早的經(jīng)驗(yàn)法則技術(shù)正消失。交通問題這些紀(jì)律不成熟： 存在著很大的問題并且仍然增長。 在 1920 輛機(jī)動車的 總數(shù)，在英國批準(zhǔn)是 650，000.50 年以后那些可比較數(shù)字在 14，950， 000 一增長系數(shù)的 23 倍.在近年成長率已經(jīng)有點(diǎn)減弱，但是這仍然是相當(dāng)多的19556,466,00019609,

52、439,000196512,938,000197014,950,000197417,247,000為了看見在每天條件的問題，考慮高速公路。如果提出趨勢，繼續(xù)， 預(yù) 計(jì)在交通在這道路上的如此的今后 15 年內(nèi)將以百分之 40 的大約增加到百 分之 50 .如果交通的這被增加的卷是成為在與今天相同的標(biāo)準(zhǔn)的計(jì)量， 行人 穿過，道路可能通過相似的百分之 40 到 50 或許交通的額外的小路需要加 寬。 在人情況里， 接受可預(yù)知的將來的需求將破壞整個(gè)都市的環(huán)境的性格,并且顯然不可接受。交通問題具有世界范圍關(guān)心， 但是不同的國家顯而易 見在在交通與逐步上升的遙遙領(lǐng)先美國里的不同的階段， 當(dāng)一個(gè)縣有很少 道

53、路和相對低的問題時(shí)， 那些國家一被打開以道路系統(tǒng)，那些生活水平和 那些需求就適合電動機(jī)運(yùn)輸都上升 ,迅速抽打沖力 .最終和舞臺對這發(fā)生哪 個(gè)易受到相當(dāng)多辯論需求適合變得滿足的小汽車，公共汽車和運(yùn)貨汽車。 . 這一階段被稱為飽和階段。對比較來說，汽車所有權(quán)把不同國家計(jì)算進(jìn)去在 1970 年印度0.01 輛/人以色列0.05輛/人日本0.09輛/人愛爾蘭0.13輛/人荷蘭0.20輛/人英國0.21輛/人西德0.23輛/人澳大利亞0.31輛/人美國0.44輛/人但是在車輛所有權(quán)方面的發(fā)展只是總的交通問題的一部分 .顯而易見，如 果一個(gè)國家有極端的寬度無限的道路，交通問題將不上升。世界上的沒有國 家能

54、滿足這要求：除其它任何事情外，不將適合每輛車輛使用道路做經(jīng)濟(jì)。 這個(gè)數(shù)字正穩(wěn)定地減少。3 個(gè)可能的解決辦法基本問題的交通因此簡單一不斷增加車輛的數(shù)量想辦法使用太少道路空間。解決的方法問題其他一不也困難選擇從 3 可能性：建造，應(yīng)付需求的足夠的大小的足夠的道路。通過限制批準(zhǔn)的車輛的數(shù)量限制對道路的需求。在(A)和(b)之間的妥協(xié)建造一些額外的道路，使用和那些已經(jīng)存在的道路網(wǎng)絡(luò)兌一他們的全部潛能， 并且同時(shí)使用一些抑制測量，限制，盡可能 需求增加。汽車仍沒有需求的可見的結(jié)局可以看見， 以及 216 由于在英國在大樓道路的 每公里費(fèi)用 100 萬英鎊左右范圍應(yīng)付一個(gè)無限制的需求的現(xiàn)代使道路的費(fèi)用 將

55、太大。增加這項(xiàng)費(fèi)用，如此狹小，喧囂的島一樣的使用空間不能被認(rèn)真地 考慮。.在洛杉磯，城市在那些停車空地到處建造適合，那些汽車。我們的城 市已經(jīng)被基本上建造， 沒有人將考慮通過在汽車周圍使他們虛弱和再造毀壞 他們的性格， 因此第一個(gè)可能的解決辦法就是規(guī)章。即使今天， 在一個(gè)至少半富裕的時(shí)代在大多數(shù)西方的世界里， 然在某種程度上是身份象征，一個(gè)威望的象征。每家庭想要擁有一輛車，并 且采取措施救或者借得到一輛。當(dāng)收入和標(biāo)準(zhǔn)上漲時(shí)，二手車成為目標(biāo)。限 制獲得私人汽車的任何行動將是非常不受歡迎的和在政治上不太可能。很多目的個(gè)人運(yùn)輸理想，它使用可能接受的買得起挨門挨戶的私人汽車 觀念的靈活性。很多目的個(gè)人

56、運(yùn)輸理想，它使用可能適應(yīng)的買得起挨門挨戶 的私人汽車觀念的靈活性 .那些群眾，運(yùn)動的人以來沿著具體走廊在有限時(shí)期 內(nèi)即. 特別要設(shè)法安排的那些旅行可能被較少容易容納。 其他運(yùn)輸方式可能更 有效率。有點(diǎn)妥協(xié)解決辦法是不可避免 基本的交通問題的答案。這是執(zhí)行 這個(gè)妥協(xié)解決辦法那，交通工程得到它所應(yīng)得。交通工程保證任何新設(shè)備沒 被過于屈尊正確地位于滿足需求。它保證現(xiàn)有的設(shè)備被完全使用，以非常有 效率的方式。 . 那些履行的這些職責(zé)需要那些選擇需求的調(diào)節(jié)可能： 在那些山 峰時(shí)期內(nèi)使那些使用的那些不那么有吸引力的汽車， 為了公共運(yùn)輸可能更 有效地使用有限的道路空間。這樣的抑制措施經(jīng)常伴隨著在公開傳送服務(wù)方面的改進(jìn)，以便接受對他 們的額外的需求。預(yù)應(yīng)力混凝土橋梁預(yù)應(yīng)力混凝土自 20 世紀(jì) 90 年代末期首次在歐洲發(fā)明以來，被廣泛應(yīng)用 于美國橋梁的建設(shè)。在美國，上千的公路橋梁建設(shè)中使用了后張預(yù)制預(yù)應(yīng)力 混凝土和現(xiàn)澆混凝土。而且，預(yù)應(yīng)力混凝土在鐵路橋梁中的應(yīng)用也變的非常 普及。并且，近些年來預(yù)應(yīng)力混凝土橋梁在不斷的應(yīng)用和改進(jìn)。短跨徑橋梁：跨徑小于 13.7m 的橋梁，稱為短跨徑