橋梁畢業(yè)設(shè)計(jì)外文翻譯--碳纖維復(fù)合材料修復(fù)混凝土橋梁結(jié)構(gòu)的詳述及應(yīng)用

1、<p>　　Structural Rehabilitation of Concrete Bridges with CFRP Composites-Practical Details and Applications</p><p>　　Riyad S. ABOUTAHA1, and Nuttawat CHUTARAT2</p><p>　　ABSTRACT: Many old e

2、xisting bridges are still active in the various highway transportation networks, carrying heavier and faster trucks, in all kinds of environments. Water, salt, and wind have caused damage to these old bridges, and scarci

3、ty of maintenance funds has aggravated their conditions. One attempt to restore the original condition; and to extend the service life of concrete bridges is by the use of carbon fiber reinforced polymer (CFRP) composite

4、s. There appear to be very limited guide</p><p>　　KEYWORDS: Concrete deterioration, corrosion of steel, bridge rehabilitation, CFRP composites.</p><p>　　1 Introduction</p><p>　　Ther

5、e are several destructive external environmental factors that limit the service life of bridges. These factors include but not limited to chemical attacks, corrosion of reinforcing steel bars, carbonation of concrete, an

6、d chemical reaction of aggregate. If bridges were not well maintained, these factors may lead to a structural deficiency, which reduces the margin of safety, and may result in structural failure. In order to rehabilitate

7、 and/or strengthen deteriorated existing bridges, thorou</p><p>　　1 Associate Professor, Syracuse University, U.S.A.</p><p>　　2 Lecturer, Sripatum University, Thailand.</p><p>　　One

8、 attempt to restore the original condition, and to extend the service life of concrete bridges is by the use of carbon fiber reinforced polymer (CFRP) composites. </p><p>　　In North America, Europe and Japan

9、, CFRP has been extensively investigated and applied. Several design guides have been developed for strengthening of concrete bridges with CFRP composites. However, there appear to be very limited guides on repair of det

10、eriorated concrete bridges with CFRP composites. This paper presents guidelines for repair of deteriorated concrete bridges, along with proper detailing. Evaluation, nondestructive testing, and rehabilitation of deterior

11、ated concrete bridges with</p><p>　　2 Deteriorated Concrete Bridges</p><p>　　Durability of bridges is of major concern. Increasing number of bridges are experiencing significant amounts of deter

12、ioration prior to reaching their design service life. This premature deterioration considered a problem in terms of the structural integrity and safety of the bridge. In addition, deterioration of a bridge has a consider

13、able magnitude of costs associated with it. In many cases, the root of a deterioration problem is caused by corrosion of steel reinforcement in concrete structures</p><p>　　Figure1 Corrosion of the steel bar

14、s is leading to a structural deficiency</p><p>　　3 Non-destructive Testing of Deteriorated Concrete Bridge Piers</p><p>　　In order to design a successful retrofit system, the condition of the ex

15、isting bridge should be thoroughly evaluated. Evaluation of existing bridge elements or systems involves review of the asbuilt drawings, as well as accurate estimate of the condition of the existing bridge, as shown in F

16、igure2. Depending on the purpose of evaluation, non-destructive tests may involve estimation of strength, salt contents, corrosion rates, alkalinity in concrete, etc.</p><p>　　Figure2 Visible concrete distre

17、ss marked on an elevation of a concrete bridge pier</p><p>　　Although most of the non-destructive tests do not cause any damage to existing bridges, some NDT may cause minor local damage (e.g. drilled holes

18、& coring) that should be repaired right after the NDT. These tests are also referred to as partial destructive tests but fall under non-destructive testing.</p><p>　　In order to select the most appropria

19、te non-destructive test for a particular case, the purpose of the test should be identified. In general, there are three types of NDT to investigate: (1) strength, (2) other structural properties, and (3) quality and dur

20、ability. The strength methods may include; compressive test (e.g. core test/rebound hammer/ ultrasonic pulse velocity), surface hardness test (e.g. rebound hammer), penetration test (e.g. Windsor probe), and pullout test

21、 (anchor test).</p><p>　　Other structural test methods may include; concrete cover thickness (cover-meter), locating rebars (rebar locator), rebar size (some rebar locators/rebar data scan), concrete moistur

22、e (acquameter/moisture meter), cracking (visual test/impact echo/ultrasonic pulse velocity), delamination (hammer test/ ultrasonic pulse velocity/impact echo), flaws and internal cracking (ultrasonic pulse velocity/impac

23、t echo), dynamic modulus of elasticity (ultrasonic pulse velocity), Possion’s ratio (ultrasonic pu</p><p>　　Quality and durability test methods may include; rebar corrosion rate – field test, chloride profil

24、e field test, rebar corrosion analysis, rebar resistivity test, alkali-silica reactivity field test, concrete alkalinity test (carbonation field test), concrete permeability (field test for permeability).</p><

25、p>　　4 Non-destructive Evaluation of Deteriorated Concrete Bridge Piers</p><p>　　The process of evaluating the structural condition of an existing concrete bridge consists of collecting information, e.g. d

26、rawings and construction & inspection records, analyzing NDT data, and structural analysis of the bridge. The evaluation process can be summarized as follows: (1) Planning for the assessment, (2) Preliminary assessme

27、nt, which involves examination of available documents, site inspection, materials assessment, and preliminary analysis, (3) Preliminary evaluation, this involve</p><p>　　If the information is insufficient to

28、 conduct evaluation to a specific required level, then a detailed evaluation may be conducted following similar steps for the above-mentioned preliminary assessment, but in-depth assessment. Successful analytical evaluat

29、ion of an existing deteriorated concrete bridge should consider the actual condition of the bridge and level of deterioration of various elements. Factors, e.g. actual concrete strength, level of damage/deterioration, ac

30、tual size of corroded r</p><p>　　5 Bridge Rehabilitation with CFRP Composites</p><p>　　Application of CFRP composite materials is becoming increasingly attractive to extend the service life of e

31、xisting concrete bridges. The technology of strengthening existing bridges with externally bonded CFRP composites was developed primarily in Japan (FRP sheets), and Europe (laminates). The use of these materials for stre

32、ngthening existing concrete bridges started in the 1980s, first as a substitute to bonded steel plates, and then as a substitute for steel jackets for seismic retrofit of br</p><p>　　CFRP composites could be

33、 used to increase the flexural and shear strength of bridge girders including pier cap beams, as shown in Figure3. In order to increase the ductility of CFRP strengthened concrete girders, the longitudinal CFRP composite

34、 sheets used for flexural strengthening should be anchored with transverse/diagonal CFRP anchors to prevent premature delamination of the longitudinal sheets due to localized debonding at the concrete surface-CFRP sheet

35、interface. In order to prevent stres</p><p>　　Deterioration of concrete bridge members due to corrosion of steel bars usually leads in loss of steel section and delamination of concrete cover. As a result, s

36、uch deterioration may lead to structural deficiency that requires immediate attention. Figure4 shows rehabilitation of structurally deficient concrete bridge pier using CFRP composites.</p><p>　　Figure3 Flex

37、ural and shear strengthening of concrete bridge pier with FRP composites</p><p>　　Figure4 Rehabilitation of deteriorated concrete bridge pier with CFRP composites</p><p>　　6 Summary and Conclusi

38、ons</p><p>　　Evaluation, non-destructive testing and rehabilitation of deteriorated concrete bridges were presented. Deterioration of concrete bridge components due to corrosion may lead to structural defici

39、encies, e.g. flexural and/or shear failures. Application of CFRP composite materials is becoming increasingly attractive solution to extend the service life of existing concrete bridges. CFRP composites could be utilized

40、 for flexural and shear strengthening, as well as for restoration of deteriorated conc</p><p>　　碳纖維復(fù)合材料修復(fù)混凝土橋梁結(jié)構(gòu)的詳述及應(yīng)用</p><p>　　Riyad S. ABOUTAHA1, and Nuttawat CHUTARAT2</p><p>　　摘

41、要：在各式各樣的公路交通網(wǎng)絡(luò)中，許多現(xiàn)有的古老橋梁，在各種惡劣的環(huán)境下，如更重的荷載和更快的車輛等條件下，依然在被使用著。沖刷、腐蝕和風(fēng)化對(duì)這些古老的橋梁已經(jīng)造成了破壞，而維修資金短缺更加劇了它們的損壞。一個(gè)利用碳纖維增強(qiáng)復(fù)合材料（CFRP）來延長混凝土橋梁的使用壽命的想法使橋梁恢復(fù)了原有的狀態(tài)。然而，采用碳纖維復(fù)合材料修復(fù)受損混凝土橋梁的指導(dǎo)和規(guī)范還非常有限。在本文中對(duì)無損探傷、無損檢測和利用碳纖維復(fù)合材料修復(fù)已遭侵蝕的橋梁的方法進(jìn)行

42、了介紹。此設(shè)計(jì)對(duì)碳纖維增強(qiáng)混凝土橋的延性，及其應(yīng)用后效果也進(jìn)行了討論和介紹。</p><p>　　關(guān)鍵詞:混凝土腐蝕，鋼筋銹蝕，橋梁修復(fù)，碳纖維復(fù)合材料</p><p><b>　　1 簡介</b></p><p>　　在這里存在幾個(gè)有害的外部環(huán)境因素影響著橋梁的耐久性。這些因素包括但又不僅限于化學(xué)物的侵蝕，受力鋼筋的銹蝕，混凝土的碳化，化學(xué)物

43、質(zhì)的聚合反應(yīng)。如果橋梁維護(hù)不好，這些因素可能導(dǎo)致結(jié)構(gòu)的受損，如結(jié)構(gòu)邊緣不穩(wěn)定或結(jié)構(gòu)損毀。為了修復(fù)日漸惡化的現(xiàn)存橋梁，應(yīng)當(dāng)對(duì)其作徹底的評(píng)估。目的是通過大致檢測剩余耐久度和承載力，評(píng)定出所有現(xiàn)存橋梁的真實(shí)情況。</p><p>　　應(yīng)用碳纖維復(fù)合材料可以恢復(fù)混凝土橋梁最初的狀況并延長其使用年限。在北美、歐洲和日本，碳纖維復(fù)合材料應(yīng)經(jīng)得到深入的研究和廣泛的應(yīng)用。碳纖維復(fù)合材料的幾個(gè)設(shè)計(jì)指南也已經(jīng)被應(yīng)用于強(qiáng)化混凝土橋梁。

44、然而，采用碳纖維復(fù)合材料修復(fù)損壞的混凝土橋梁的指導(dǎo)和規(guī)范還非常有限。本文通過合適的例子給出了修復(fù)受損混凝土梁橋的準(zhǔn)則，列出了評(píng)估、無損檢測、碳纖維復(fù)合材料復(fù)原受損混凝土橋梁。碳纖維復(fù)合材料的成功應(yīng)用由于良好的細(xì)節(jié)設(shè)計(jì)，它主要考慮了集中力在碳纖維復(fù)合材料中依靠混凝土與碳纖維復(fù)合材料接觸面間的粘合劑轉(zhuǎn)移。此設(shè)計(jì)對(duì)碳纖維增強(qiáng)混凝土橋的延性和反應(yīng)的效果也進(jìn)行了討論和介紹。</p><p>　　2 混凝土橋梁的損壞<

45、/p><p>　　橋梁的使用年限應(yīng)該給予極大地關(guān)注。越來越多的橋梁在達(dá)到設(shè)計(jì)使用年限之前出現(xiàn)令人側(cè)目的破損。這些過早出現(xiàn)的損壞使得橋梁的結(jié)構(gòu)可靠性和安全性成為</p><p>　　1副教授，雪城大學(xué)，美國</p><p>　　2講師，斯巴頓大學(xué)，泰國</p><p>　　了值得考慮的問題?？偟膩碚f，橋梁的損壞與考慮它的花費(fèi)多少是緊密相關(guān)的。在很多

46、情況下，損壞問題的根源是混凝土結(jié)構(gòu)中受力鋼筋的腐蝕。通常由混凝土保護(hù)層預(yù)防受力筋的腐蝕。然而，這些具有代表性的問題，如混凝土質(zhì)量差、不適當(dāng)?shù)脑O(shè)計(jì)或施工和周圍惡劣的環(huán)境導(dǎo)致了鋼筋的腐蝕。如果不及時(shí)處理像鋼筋腐蝕這種耐久性問題，可能會(huì)引起受力不均問題，進(jìn)而導(dǎo)致結(jié)構(gòu)失穩(wěn)，如圖1所示。</p><p>　　圖1 鋼筋的銹蝕導(dǎo)致的結(jié)構(gòu)失穩(wěn)</p><p>　　3 損壞的混凝土梁橋墩柱的無損檢測<

47、;/p><p>　　為了設(shè)計(jì)一個(gè)成功的新式系統(tǒng)，應(yīng)該對(duì)橋梁現(xiàn)有的情況作徹底評(píng)估。評(píng)價(jià)現(xiàn)有橋梁的元素或體系需要翻看asbuilt圖紙，才能準(zhǔn)確的評(píng)估出現(xiàn)有橋梁的狀況，如圖2所示。根據(jù)評(píng)估的目的，無損測試應(yīng)該包括的內(nèi)容：強(qiáng)度的檢測，鹽度，腐蝕率，混凝土中堿含量等等。</p><p>　　雖然大多數(shù)的無損測試對(duì)現(xiàn)有橋梁不會(huì)造成任何損壞，一些無損檢測可能導(dǎo)致的輕微局部損傷（如鉆洞取芯），在無損檢測完畢

48、后應(yīng)予以修復(fù)。這些測試也被叫作部分破壞性測試,但屬于無損檢測。</p><p>　　圖2 混凝土橋墩可見缺陷正面圖</p><p>　　為了針對(duì)特殊情況選擇最合適的無損檢測，應(yīng)該明確測試的目的。一般來說,有三種類型的無損檢測進(jìn)行調(diào)查：（1）強(qiáng)度；（2）其他結(jié)構(gòu)性質(zhì)；（3）質(zhì)量及耐久性。強(qiáng)度測試的方法可能包括：抗壓測試（如軸心抗壓、反彈測試儀、超聲波脈沖速度檢測）；表面硬度測試（如反彈儀測試

49、）；貫入度試驗(yàn)（如溫莎探針）；拉拔試驗(yàn)（錨索抗拔試驗(yàn)）。</p><p>　　其它結(jié)構(gòu)測試方法還包括：混凝土保護(hù)層厚度（保護(hù)層測量）；定位鋼筋位置（鋼筋定位器）；鋼筋尺寸（某些鋼筋定位器、鋼筋數(shù)據(jù)掃描儀）；混凝土的濕度（含水量測試儀、水分測定儀）；混凝土裂縫檢查（外觀鑒定、回音法、超聲波脈沖回波速度檢查法）；混凝土分層剝離（錘擊試驗(yàn)、超聲波脈沖回波速度檢查法、回音法）；缺陷和內(nèi)部開裂（超聲波脈沖回波速度檢查法、回

50、音法）；動(dòng)態(tài)彈性模量（超聲波脈沖回波速度檢查法）；泊松比（超聲波脈沖回波速度檢查法）；混凝土板或墻的厚度（超聲波脈沖回波速度檢查法）；碳纖維復(fù)合材料剝離（錘擊試驗(yàn)、紅外線溫度記錄技術(shù)）；混凝土表面缺陷（外觀鑒定）。</p><p>　　質(zhì)量和耐久性試驗(yàn)方法包括：鋼筋銹蝕率—現(xiàn)場試驗(yàn)，現(xiàn)場檢測剖面氯化物，驗(yàn)定鋼筋銹蝕率，測試鋼筋電阻率，現(xiàn)場測定堿質(zhì)與粒料反應(yīng)活性，混凝土堿度測定（碳化測定），混凝土的滲透性（現(xiàn)場滲透

51、性試驗(yàn)）。</p><p>　　4 損壞的混凝土梁橋墩柱的無損探傷</p><p>　　對(duì)一個(gè)現(xiàn)有混凝土橋梁結(jié)構(gòu)特征的評(píng)估由各種信息組成，如圖紙、構(gòu)筑物的檢查記錄，無損檢測的分析數(shù)據(jù)和橋梁的結(jié)構(gòu)分析。評(píng)估過程可以概括如下：（1）計(jì)劃評(píng)估；（2）預(yù)備評(píng)估，主要包括現(xiàn)有文件檢查、實(shí)地檢查、材料檢驗(yàn)和初步分析；（3）初步評(píng)估，主要有檢查階段，審查階段和完成階段。（4）有關(guān)成本影響的分析。<

52、/p><p>　　如果上述提供的信息，不足以用來進(jìn)行高水平的評(píng)估。那么，我們做完上述的初步評(píng)估的步驟之后，可以再做一個(gè)詳細(xì)的、深入的評(píng)估。對(duì)于某個(gè)現(xiàn)存損壞的混凝土橋梁成功地分析評(píng)估應(yīng)當(dāng)考慮橋梁的實(shí)際情況及它的各部分的損壞程度。如果在適當(dāng)?shù)囊欢螘r(shí)間內(nèi)很難完成如此詳細(xì)的分析，那么就可能需要談及的依靠現(xiàn)場試驗(yàn)得到的實(shí)際橋梁的評(píng)估。</p><p>　　5 碳纖維復(fù)合材料修復(fù)受損橋梁的應(yīng)用</p

53、><p>　　碳纖維復(fù)合材料的應(yīng)用延長了既有混凝土橋梁的使用年限而變得越來越引人注目。在橋梁的外部粘結(jié)碳纖維復(fù)合材料加強(qiáng)現(xiàn)有橋梁的技術(shù)被廣泛應(yīng)用在日本（纖維增強(qiáng)塑料板）和歐洲（多層纖維板）。在20世紀(jì)80年代，這些材料被應(yīng)用于加強(qiáng)既有混凝土橋梁，最先是被用來替代鋼板，后來被用來替代鋼套作為橋墩的耐震補(bǔ)強(qiáng)。碳纖維復(fù)合材料由纖維強(qiáng)化復(fù)合材料與合成樹脂基質(zhì)粘結(jié)在一起組成。纖維以其獨(dú)特的結(jié)構(gòu)性能使兩者良好復(fù)合。樹脂基質(zhì)支撐并

54、保護(hù)著纖維，將外施荷載以剪應(yīng)力的方式傳遞給纖維。大部分在建筑市場上能買到的碳纖維復(fù)合材料加固系統(tǒng)都是由單向纖維嵌套在樹脂基質(zhì)中構(gòu)成，最具代表性的是環(huán)氧樹脂。碳纖維的有限的極限應(yīng)變可能會(huì)限制強(qiáng)化涂層中的元素的形變能力。然而，在交通荷載作用下，結(jié)構(gòu)在破壞之前且全局的形變?cè)诳山邮艿某潭葍?nèi)，碳纖維復(fù)合材料板與混凝土基質(zhì)之間局部的脫膠是被允許的。</p><p>　　碳纖維復(fù)合材料可用于增加包括蓋梁在內(nèi)的橋主梁的抗彎及抗剪

55、強(qiáng)度，如圖3所示。為了增加碳纖維復(fù)合材料加強(qiáng)的混凝土主梁的延性，防止由于混凝土基質(zhì)與碳纖維復(fù)合材料接觸面之間產(chǎn)生局部脫膠而造成的縱向板過早剝離，應(yīng)將用于增強(qiáng)抗彎強(qiáng)度的縱向碳纖維復(fù)合材料板、橫向板及對(duì)角板互相錨固。為了防止在混凝土構(gòu)件的轉(zhuǎn)角處產(chǎn)生應(yīng)力集中和碳纖維復(fù)合材料板過早斷裂，這些轉(zhuǎn)角應(yīng)當(dāng)是不小于50mm（2.0英寸）半徑的圓角，如圖3所示。</p><p>　　圖3 碳纖維復(fù)合材料混凝土墩柱彎剪強(qiáng)度的加強(qiáng)&l

56、t;/p><p>　　由于鋼筋的銹蝕而導(dǎo)致的鋼筋截面面積的損失和混凝土保護(hù)層的損壞是混凝土橋梁構(gòu)件損壞的根本原因。因此應(yīng)該時(shí)刻注意像這樣可能會(huì)導(dǎo)致結(jié)構(gòu)失穩(wěn)的損壞。碳纖維復(fù)合材料對(duì)受損橋梁結(jié)構(gòu)的修復(fù)如下圖4所示。</p><p>　　圖4 碳纖維復(fù)合材料對(duì)受損橋梁的修復(fù)</p><p><b>　　6 概要和結(jié)論</b></p><

57、;p>　　在上文中對(duì)測評(píng)橋梁、無損測試和對(duì)受損混凝土橋梁的修復(fù)進(jìn)行了介紹。鋼筋的銹蝕可能會(huì)導(dǎo)致混凝土橋梁的構(gòu)件發(fā)生彎曲或者剪切破壞。由于碳纖維復(fù)合材料的應(yīng)用延長了現(xiàn)有混凝土橋梁的使用年限，因此越來越多的人正在對(duì)它投入關(guān)注。碳纖維復(fù)合材料可以被應(yīng)用于增加構(gòu)件的抗彎剪強(qiáng)度，也可以被用來修復(fù)混凝土橋梁的受損構(gòu)件。碳纖維復(fù)合材料可以很好的應(yīng)用于防止應(yīng)力集中和構(gòu)件過早的破裂及損壞。在極易被腐蝕的環(huán)境中，防腐蝕的碳纖維復(fù)合材料體系應(yīng)當(dāng)被應(yīng)用，