外文翻譯----混凝土橋結(jié)構(gòu)可靠性研究

1、<p><b>　　附錄A 譯文</b></p><p>　　混凝土橋結(jié)構(gòu)可靠性研究</p><p>　　鋼筋混凝土橋結(jié)構(gòu)敏感于多種惡化機制，包括堿趨于緩和行動和氯化物進入。 實際的研究已經(jīng)被與這些機制和其他問題聯(lián)系起來承擔。 這一直特別在那些案件在過去的大約20年，那些目標是鑒定引起，結(jié)果并且發(fā)展補救策略。 這已經(jīng)改進加強的混凝土的理解長期性能并且導致技

2、術的發(fā)展增加惡化抵抗。 </p><p>　　目前，在一個問題已經(jīng)被鑒定之后，最共同的方法是行動，被稱為重新活躍的維修。 這不可能以前最經(jīng)濟解決辦法，在許多場合，維修比比預防處理方法昂貴。 不過，在惡化是明顯的之前，擁有人經(jīng)常不愿意為預防處理方法支付。 處理方法的盡快應用歸根結(jié)底可能不是這個最佳的解決辦法。 綜合惡化和性能預測模型化對很重要支持積極計劃和檢查，試驗與維修。 這作為年齡和理由給提供資金的維護變得越來

3、越批判性的基礎設施變得越來越重要。</p><p>　　性能評價可以被通過調(diào)查，測試和正式的計算取得， 最好基于盡可能準確代表結(jié)構(gòu)的狀況的場所數(shù)據(jù)。 以把提前檢測的 惡化模型和評價結(jié)合起來工具和性能準則(在元素， 結(jié)構(gòu)或者組水平) 基于維護關于與時間有關的性能剖面圖的政體變得可能。 這鑒于花費程序的全部妻子特別相關。</p><p>　　可靠性分析已經(jīng)作為在這個多客觀的管理過程里的一件重要

4、的工具出現(xiàn)，這必須考慮到安全，功能性和持續(xù)標準。 用簡單術語，一個結(jié)構(gòu)或者一個系統(tǒng)的可靠性是取得特別的性能水平的可能性。 可能性或者可能是這個適當?shù)拇胧驗槿抗こ滔到y(tǒng)對不確定敏感，起因于隨便現(xiàn)象和不完全的知識。 在結(jié)構(gòu)工程方面的可靠性分析使與裝，材料，惡化，模型化和其他因素相關的不確定的確定數(shù)量成為可能。 這些統(tǒng)一到估計在一個結(jié)構(gòu)的使用年限期間達到保證性能水平的可能性的一種方法中。 兩個對安全水平的校準來說在規(guī)則和標準和改進和精煉評

5、價方法學里，這種方法正越來越被在橋工程使用。 這篇文章的目的是在管理易受到惡化的橋過程中略述它的申請。</p><p><b>　　橋梁性能指標</b></p><p>　　當今英國評價代碼最后限制說明(ULS)并且不明確要求使用能力所限制的檢查說明(ULS)。 可以認為一種現(xiàn)有的結(jié)構(gòu)已經(jīng)經(jīng)歷SLS在它的生命期間裝。 不過，被廣泛地相信的撓度的SLS 標準和斷裂不完全

6、考慮到那些問題通過惡化矯柔造作。 基于惡化的象弄臟的銹那樣的標準，失效并且弄碎需要被認為，因為他們清楚影響橋性能，起作用和金融。 這些經(jīng)常關于連接管理策略證明有勢力的因素。</p><p>　　通過明確地考慮到和指定性能水平， 為了建立檢查與維修政體適合特別的結(jié)構(gòu)/ 成員工程師知道重要惡化指標。 這些性能水平超時可以改變， 由于在功能，裝，例如的結(jié)構(gòu)重要等等方面的變化， 在實際之間的關系和要求性能被用圖1 顯示的

7、圖解概念化。 因此，可靠性分析可能用來闡述性能將超過要求的可能性，因此估計結(jié)構(gòu)的可靠性。 性能測量可能與安全，功能性或者任何其他合適的標準有關</p><p>　　解決由氯化物引起的腐蝕</p><p>　　這項特別的工程專心于加強的混凝土惡化的一個具體的領域，特別是起因于氯化物進入。 氯化物存在于在冬天在英國使用的除冰的鹽。 氯離子遷移雖然使凝固，例如以吸收和擴散。 在合適條件下，他們起

8、動加固酒吧腐蝕。 腐蝕機制產(chǎn)生銹。 金屬的被增加的體積，由于銹，導致斷裂，失效并且具體的蓋子的弄碎。 在更迅速和廣泛的加固腐蝕里的這結(jié)果。</p><p>　　在一個問題已經(jīng)被鑒定之后，最共同的方法是行動，被稱為重新活躍的維修。 這不可能以前最經(jīng)濟解決辦法，在許多場合，維修比比預防處理方法昂貴。 不過，在惡化是明顯的之前，擁有人經(jīng)常不愿意為預防處理方法支付。 處理方法的盡快應用歸根結(jié)底可能不是這個最佳的解決辦法。

9、 綜合惡化和性能預測模型化對很重要支持積極計劃和檢查，試驗與維修。 這作為年齡和理由給提供資金的維護變得越來越批判性的基礎設施變得越來越重要。</p><p>　　性能評價可以被通過調(diào)查，測試和正式的計算取得， 最好基于盡可能準確代表結(jié)構(gòu)的狀況的場所數(shù)據(jù)。 以把提前檢測的 惡化模型和評價結(jié)合起來工具和性能準則(在元素， 結(jié)構(gòu)或者組水平) 基于維護關于與時間有關的性能剖面圖的政體變得可能。 這鑒于花費程序的全部妻子

10、特別相關。</p><p>　　如果共同不及格，加強在伸縮接頭下面位于的混凝土橋元素特別對氯化物攻擊敏感。 在英國的公路高架橋通常由交叉梁直接在伸縮接頭下面位于的加強的混凝土組成，(參閱圖2)。 很多交叉梁已經(jīng)遭受嚴厲的加固腐蝕，失效和弄碎。 一典型例子在3 圖讓看，加固覆蓋在哪里交叉梁有失效。</p><p>　　一概率惡化模特適合加強零部件被發(fā)展的混凝土橋，考慮到這些結(jié)構(gòu)和他們的環(huán)境的

11、特性。 它以為擴散和吸收都通過混凝土扮演氯化作用遷移的角色， 在到達交叉梁 表面的除冰的鹽的數(shù)量方面的變化性和每年這些數(shù)量怎樣變化。 考慮交叉梁的典型氯化物暴露區(qū)域包括：</p><p>　　●位于破壞的擴大的節(jié)點下面的水平表面。</p><p>　　●位于的這種節(jié)點是浸于水中的。</p><p>　　●位于擴大的緊密的節(jié)點下面的垂直表面，它通常是暴露在道路中的氯化

12、物容易飛濺到的地方等。</p><p>　　數(shù)據(jù)適合很多惡化變量能由實驗室而來雖然研究，有相似的數(shù)據(jù)真正的結(jié)構(gòu)不在。 一個模型的重要的特征是修改最初預言的設備， 基于出版(認為為' 早先') 的數(shù)據(jù)，使用信息和數(shù)據(jù)從實際結(jié)構(gòu)直接獲得。 可靠性分析適合于這個目的好象它能容易包含附加數(shù)據(jù)，不斷改進達到一個性能目標的可能性。 概念與相似不斷改進到達準時的可能性當在一火車上時，有剛剛獲得一些額外信息關于操

13、作條件在前面。</p><p>　　為一個交叉梁 氯化物暴露區(qū)域概率的惡化模型生產(chǎn)的典型的結(jié)果， 類似于用圖3 顯示的領域，圖4.認為一個40%的開始的門檻被為第一個檢查指定， 模型建議它在8 年之后被承擔。 假定檢查表明相當較少的腐蝕開始(僅僅這些大約占10%)并且把歸于， 由于通過場所調(diào)查，對具體的蓋子比期望高，性能外形的修正的預言可能被產(chǎn)生。 橋管理行動可能然后被照著改變。</p><p

14、>　　說明一個限制怎樣說明這個區(qū)域的剖面圖隨以為的條件而變。 惡化模式和契約結(jié)合起來限制狀態(tài)方程。 因此， 組成部分有一個目標每年1 * 10-5的名義上的失效概率， 外形1 建議僅僅17到18 年的壽命，而第2 剖面圖建議30到31 年。 當與橋的正常的預期壽命相比較時，兩個都是短的壽命。 不過，與這些結(jié)果有關系的起始條件以為甲板關節(jié)從開始已經(jīng)失敗。 當他們被為完整的建筑物發(fā)展時，或者，塑造契約強度的表達方式可能是過于保守的。&

15、lt;/p><p>　　可靠性分析提供對待不確定的一種合理和一致的框架。 這可能是相似的結(jié)構(gòu)可以被通過超時改變的性能外形比較用的一件有用的管理工具。 結(jié)果必須被小心解釋，并且經(jīng)得起常識和工程判別法。 敏感性分析被強烈推薦，并且可能被容易執(zhí)行。很多數(shù)據(jù)收集和測試在惡化模型過程中做的解釋。 假使有與保持安全，可靠基礎結(jié)構(gòu)系統(tǒng)相關的費用，這一凝固的努力以勤奮和組織能產(chǎn)生結(jié)實的好處在哪里的一地區(qū)。</p>&l

16、t;p>　　說明一個限制怎樣說明這個區(qū)域的剖面圖隨以為的條件而變。 惡化模式和契約結(jié)合起來限制狀態(tài)方程。 因此， 組成部分有一個目標每年1 * 10-5的名義上的失效概率， 外形1 建議僅僅17到18 年的壽命，而第2 剖面圖建議30到31 年。 當與橋的正常的預期壽命相比較時，兩個都是短的壽命。 不過，與這些結(jié)果有關系的起始條件以為甲板關節(jié)從開始已經(jīng)失敗。 當他們被為完整的建筑物發(fā)展時，或者，塑造契約強度的表達方式可能是過于保守

17、的。</p><p>　　可靠性分析提供對待不確定的一種合理和一致的框架。 這可能是相似的結(jié)構(gòu)可以被通過超時改變的性能外形比較用的一件有用的管理工具。 結(jié)果必須被小心解釋，并且經(jīng)得起常識和工程判別法。 敏感性分析被強烈推薦，并且可能被容易執(zhí)行。很多數(shù)據(jù)收集和測試在惡化模型過程中做的解釋。假使有與保持安全，可靠基礎結(jié)構(gòu)系統(tǒng)相關的費用，這一凝固的努力以勤奮和組織能產(chǎn)生結(jié)實的好處在哪里的一地區(qū)。這項特別的工程專心于加強

18、的混凝土惡化的一個具體的領域，特別是起因于氯化物進入。氯化物存在于在冬天在英國使用的除冰的鹽。 氯離子遷移雖然使凝固，例如以吸收和擴散。 在合適條件下，他們起動加固酒吧腐蝕。腐蝕機制產(chǎn)生銹。金屬的被增加的體積，由于銹，導致斷裂，失效并且具體的蓋子的弄碎。在更迅速和廣泛的加固腐蝕里的這結(jié)果。</p><p>　　說明一個限制怎樣說明這個區(qū)域的剖面圖隨以為的條件而變。 惡化模式和契約結(jié)合起來限制狀態(tài)方程。因此，組成部

19、分有一個目標每年1 * 10-5的名義上的失效概率，外形1 建議僅僅17到18 年的壽命，而第2 剖面圖建議30到31 年。當與橋的正常的預期壽命相比較時，兩個都是短的壽命。不過，與這些結(jié)果有關系的起始條件以為甲板關節(jié)從開始已經(jīng)失敗。當他們被為完整的建筑物發(fā)展時，或者，塑造契約強度的表達方式可能是過于保守的。</p><p>　　如果共同不及格，加強在伸縮接頭下面位于的混凝土橋元素特別對氯化物攻擊敏感。 在英國的

20、公路高架橋通常由交叉梁直接在伸縮接頭下面位于的加強的混凝土組成。很多交叉梁已經(jīng)遭受嚴厲的加固腐蝕，失效和弄碎。 一典型例子在3 圖讓看，加固覆蓋在哪里交叉梁有失效。</p><p><b>　　總而言之： </b></p><p>　　這項工作受到公路辦事處的的大力支持而得以順利進行， 所表示的觀點意見僅代表作者的想法，并不一定被公路辦事處接受或分享。</p&

21、gt;<p><b>　　附錄B 外文原文</b></p><p>　　Reliability of concrete bridge structure</p><p>　　Reinforced concrete structures are susceptible to a variety of deterioration mechanisms, i

22、ncluding alkali-thaw action and chloride ingress. Substantial research has been undertaken in relation to these mechanisms and other problems. This has particularly been the case over the last 20 years or so, where the o

23、bjective has been to identify causes, consequences and develop remediation strategies. This has improved understanding of long-term behaviour of reinforced concrete and resulted in the devel</p><p>　　At pres

24、ent, the most common approach is to act after a problem has been identified, known as re-active maintenance. This may not be the most economic solution since, in many cases, maintenance is more costly than preventative t

25、reatments. However, owners are often reluctant to pay for preventative treatments before deterioration is apparent. Early application of treatments may not be the optimal solution in the long run. Integrated deterioratio

26、n and performance prediction modeling is essential to</p><p>　　Performance assessment can be achieved through surveys, testing and formal calculations, ideally based on site data that represent, as accuratel

27、y as possible, the state of the structure. By integrating predictive deterioration models with assessment tools and performance criteria (at element, structure or group level) it becomes possible to base the maintenance

28、regime on time-dependent performance profiles. This is particularly relevant in the context of whole-wife costing procedures.</p><p>　　Substantial research has been undertaken in relation to these mechanisms

29、 and other problems. This has particularly been the case over the last 20 years or so, where the objective has been to identify causes, consequences and develop remediation strategies. This has improved understanding of

30、long-term behaviour of reinforced concrete and resulted in the development of techniques to increase deterioration resistance.</p><p>　　At present, the most common approach is to act after a problem has been

31、 identified, known as re-active maintenance. This may not be the most economic solution since, in many cases, maintenance is more costly than preventative treatments. However, owners are often reluctant to pay for preven

32、tative treatments before deterioration is apparent. Early application of treatments may not be the optimal solution in the long run. Integrated deterioration and performance prediction modeling is essential to</p>

33、<p>　　Reliability analysis has emerged as an important tool in this multi-objective management process, which must take into account safety, functionality and sustainability criteria. In simple terms, the reliabili

34、ty of a structure or a system is the probability of achieving a particular performance level. Probability or likelihood is the appropriate measure, since all engineering systems are susceptible to uncertainties, arising

35、 from random phenomena and incomplete knowledge. Reliability analysis in</p><p>　　Although data for many deterioration variables can be derived from laboratory studies, there is an absence of similar data re

36、al structures. An important feature of the model is the facility to modify initial predictions, based on published (known as ‘prior’) data, using information and data obtained directly from the actual structures. Reliabi

37、lity analysis is appropriate for this pursose as if it can readily incorporate additional data, updating the probability of reaching a performance target. </p><p>　　Typical results produced by the probabilis

38、tic deterioration model for a crossbeam chloride exposure zone, similar to the delaminated area shown in Figure 3,are shown in Figure 4.Assuming a threshold of 40% initiation is specified for the first inspection, the mo

39、del suggests that it should be undertaken after eight years .Assuming that inspection indicates significantly less corrosion initiation (e.g.only about 10%) and attributed, through site investigations, to concrete cover

40、being higher than </p><p>　　Figure 5 illustrates how a limit state profile for this zone changes with assumed conditions. The deterioration model has been integrated with bond limit state equations .Thus, as

41、suming that the component has a target nominal probability of failure of 1×10-5 per year, profile 1 suggests a lifetime of only 17 to 18 years, whereas Profile 2 suggests 30 to 31 years. Both are short lifetimes whe

42、n compared with the normal life expectancy of bridges. However, initial conditions relating to these resul</p><p>　　Substantial research has been undertaken in relation to these mechanisms and other problems

43、. This has particularly been the case over the last 20 years or so, where the objective has been to identify causes, consequences and develop remediation strategies. This has improved understanding of long-term behaviour

44、 of reinforced concrete and resulted in the development of techniques to increase deterioration resistance.</p><p>　　At present, the most common approach is to act after a problem has been identified, known

45、as re-active maintenance. This may not be the most economic solution since, in many cases, maintenance is more costly than preventative treatments. However, owners are often reluctant to pay for preventative treatments b

46、efore deterioration is apparent. Early application of treatments may not be the optimal solution in the long run. Integrated deterioration and performance prediction modeling is essential to</p><p>　　Bridge

47、performance criteria</p><p>　　Current UK assessment codes are concerned with ultimate limit states (ULS) and do not explicitly require checking of serviceability limit states (ULS). It is assumed that an exi

48、sting structure has experienced SLS loads during its life. However, the widely accepted SLS criteria of deflection and cracking do not fully take into account the problems posed by deterioration. Deterioration-based crit

49、eria such as rust staining, delamination and spalling need to be considered because they clearly influe</p><p>　　By explicitly considering and specifying performance levels, the engineer is aware of the impo

50、rtant deterioration indicators in order to establish the inspection and maintenance regime for the particular structure/member. These performance levels may change over time, due to changes in function, loading, structur

51、e importance etc. for example, the relationship between actual and required performance is conceptualized by the diagram shown in Figure 1. Thus, reliability analysis may be used to form</p><p>　　Modeling ch

52、loride-induced deterioration </p><p>　　This particular project concentrated on one specific area of reinforced concrete deterioration, specifically arising from chloride ingress. Chlorides are present in de-

53、icing salts used in the UK during winter. Chloride ions migrate though the concrete, e.g. by absorption and diffusion. Under suitable conditions, they initiate reinforcement bar corrosion. The corrosion mechanism produce

54、s rust. The increased volume of the metal, due to the rust, leads to cracking, delamination and spalling of the </p><p>　　Reinforced concrete bridge elements located below expansion joints are particularly s

55、usceptible to chloride attack if the joint fails. Highway viaducts in the UK typically consist of a reinforced concrete crossbeam directly located below the expansion joint,(see Figure 2).Many crossbeams have suffered se

56、vere reinforcement corrosion, delamination and spalling. A typical example is shown in Figure 3, where the reinforcement cover over the crossbeam has delaminated. </p><p>　　A probabilistic deterioration mode

57、l for reinforced concrete bridge components was developed, taking into account the characteristics of these structures and their environment. It assumes that both diffusion and absorption play a part in chlotide migratio

58、n through the concrete, the variability in the quantity of de-icing salts reaching the crossbeam surface and how these quantities vary annually. Typical chloride exposure zones considered for the crossbeams include the:

59、</p><p>　　● Horizontal surface below a failed </p><p>　　● expansion joint where water ponding can occur </p><p>　　● vertical surface below a failed expansion joint </p><p

60、>　　surfaces below an intact expansion joint, but exposed to traffic spray etc.</p><p>　　Although data for many deterioration variables can be derived from laboratory studies, there is an absence of simila

61、r data real structures. An important feature of the model is the facility to modify initial predictions, based on published (known as ‘prior’) data, using information and data obtained directly from the actual structures

62、. Reliability analysis is appropriate for this pursose as if it can readily incorporate additional data, updating the probability of reaching a performance target. </p><p>　　Typical results produced by the p

63、robabilistic deterioration model for a crossbeam chloride exposure zone, similar to the delaminated area shown in Figure 3,are shown in Figure 4.Assuming a threshold of 40% initiation is specified for the first inspectio

64、n, the model suggests that it should be undertaken after eight years .Assuming that inspection indicates significantly less corrosion initiation (e.g.only about 10%) and attributed, through site investigations, to concre

65、te cover being higher than </p><p>　　Laboratory and site data are essential for improved deterioration modeling and reliability .Much data collection and test interpretations made in the deterioration models

66、. Given the costs associated with maintaining safe, reliable infrastructure systems, this is an area where a concreted effort by industry and organizations could yield substantial benefits.</p><p>　　Figure 5

67、 illustrates how a limit state profile for this zone changes with assumed conditions. The deterioration model has been integrated with bond limit state equations .Thus, assuming that the component has a target nominal pr

68、obability of failure of 1×10-5 per year, profile 1 suggests a lifetime of only 17 to 18 years, whereas Profile 2 suggests 30 to 31 years. Both are short lifetimes when compared with the normal life expectancy of bri

69、dges. However, initial conditions relating to these resul</p><p>　　Concluding remarks</p><p>　　Reliability analysis provides a rational and consistent framework for treating uncertainties .It ca

70、n be a useful management tool with which similar structures can be compared through performance profiles which change over time. The results must be interpreted with care, and stand up to common sense and engineering jud

71、gement . Sensitivity analysis is strongly recommended, and can be readily performed. </p><p>　　Laboratory and site data are essential for improved deterioration modeling and reliability .Much data collection

72、 and test interpretations made in the deterioration models. Given the costs associated with maintaining safe, reliable infrastructure systems, this is an area where a concreted effort by industry and organizations could

73、yield substantial benefits. </p><p>　　Acknowledgements</p><p>　　This work was performed with the support of the Highways Agency. The views expressed are those of the authors and are not necessar