土木工程畢業(yè)設(shè)計外文翻譯

1、畢業(yè)設(shè)計（論文） 外文翻譯設(shè)計（論文）題目：寧波新城藝術(shù)賓館2#樓結(jié)構(gòu)設(shè)計與預(yù)算學(xué)專院名稱：業(yè)：建筑工程土木工程學(xué)指生導(dǎo)姓教名：師：顧 麗敏學(xué)號：袁堅06404010101敏2010 年 01 月 10 日寧波工程學(xué)院畢業(yè)設(shè)計（論文） PAGE 13外文原文 I ：A fundamental explanation of the behaviour of reinforced concrete beams in flexure basedon the properties of concrete under multiaxial stressM. D. KotsovosDepartment o

2、f CivilEngineering, Imperial College of Science and Technology, London (U. K.)The paper questions the validityof the generally accepted view that for a reinforced concretestructure to exhibit ductile behaviour under increasing load it is necessary for the stressstrain relationships of concrete to ha

3、ve a gradually descending post-ultimate branch.Experimental data are presented for reinforced concrete beams in bending which indicate the presence of longitudinalcompressive strains on the compressive face in excess of 0.0035. It is shown that these strains, which are essential for ductile behaviou

4、r, are caused by acomplex multiaxial compressive state of stress below ultimate strength rather than postultimate material characteristics. The presenceof a complex stress system provides a fundamental explanation for beam behaviour which does not affect existing design procedures.INTRODUCTIONThe pl

5、ane sections theory not, onlyis generally considered todescribe realistically the deformation responseof reinforced and prestressedconcrete beams under flexure and axial load, but is also formulated so that it provides a design tool noted for both its effectiveness and simplicity 1. The theory descr

6、ibes analytically the relationship between load-carrying capacity and geometric characteristics of a beambyconsideringtheequilibriumconditionsatcriticalcross-sections. Compatibility of deformation issatisfied by the plane cross-sections remain plane assumption and the longitudinal concrete and steel

7、 stresses are evaluated by the material stress-strain characteristics. Transverse stressesand strains are ignored for the purposes of simplicity.The stress-strain characteristics of concrete in compression are considered to be adequately described by the deformational responseof concrete specimens s

8、uch as prisms or cylinders under uniaxial compression and the stress distribution in the compression zone of a cross-section at the ultimate limit state, as proposed by current codes of practice such as CP 110 1, exhibits a shape similar to that shown in figure 1.The figure indicates that the longit

9、udinal stress increases with thedistance from the neutral axis up to a maximum value and then remains constant. Such a shape of stress distribution has been arrived at on the basis of both safety considerations and the widely held view that the stress-strain relationship of concrete in compression c

10、onsists of both an ascending and a gradually descending portion (seefig. 2). The portion beyond ultimate defines the post-ultimate stress capacity ofthe material which, Typical stress-strain relationship for concrete in compression. as indicated in figure 1, is generally considered to make a major c

11、ontribution to the maximum load-carrying capacity of the beam.However, a recent analytical investigation of the behaviour of concrete under concentrations of load has indicated that the post-ultimate strength deformational response of concrete under compressive states of stress has no apparent effec

12、t on the overall behaviour of the structural forms investigated ( 2, 3). If such behaviour is typical for any structure, then the large compressivestrains (in excess of 0.0035) measured on the top surface of a reinforced concretebeam at its ultimate limitstate (see fig. 1), cannot be attributed to p

13、ost-ultimate uniaxial stress-strain characteristics. Furthermore, since the compressive strain at the ultimate strength level of any concrete under uniaxial compression is of the order of0.002 (see fig. 2), it would appear that a realistic prediction of the beam response under load cannot be based s

14、olelyon the ascending portionofthe uniaxial stress-strain relationship of concrete.In view of the above, the work described in the following appraises the widely held view that a uniaxial stress-strainrelationship consisting of an ascending and a gradually descending portion is essential for the rea

15、listic description of the behaviour of a reinforced concrete beam in flexure. Results obtained from beams subjected to flexure under two-point loading indicate that the large strains exhibited by concrete in the compression zone of the beams are due to a triaxial state of stress rather than the unia

16、xial post-ultimate stress-strain characteristics of concrete. It is shown that the assumption that thematerialitselfsuffers a completeand immediateloss of load-carrying capacity when ultimate strength is exceeded is compatible with the observedductilestructuralbehaviourasindicatedbyload-deflexionor

17、moment-rotation relationships.EXPERIMENTAL DETAILSSpecimensThree rectangular reinforced concrete beams of 915 mm span and 102 mm height x 51 mm width cross-section were subjected to two-point load with shear spans of 305 mm (see fig. 3). The tension reinforcement consisted of two 6 mm diameter bars

18、witha yield load of 11.8 kN. The bars were bent back at the ends of the beams so as to providecompressionreinforcementalongthewholelengthoftheshear spans.Compression and tension reinforcement along each shear span were linked by seven 3.2 mm diameter stirrups. Neither compression reinforcement nor s

19、tirrups wereprovided in the central portionof the beams. Due to the above reinforcement arrangement all beams failed in flexure rather than shear, although the shear span to effective depthratio was 3.The beams, together with control specimens, were cured under damp hessian at20 for seven days and t

20、hen stored in the laboratory atmosphere (20 o C and 40%R.H.) for about 2 months, until tested. Full details of the concrete mix used are given in table I.TestingLoad was applied through a hydraulic ram and spreader beam in increments of approximately 0.5 kN. Ateach increment the load was maintained

21、constant for approximately 2 minutes in order to measure the load and the deformation response of the specimens. Load was measured by using a load cell and deformation response by using both20mmlongelectricalresistance strain gauges and displacement transducers. The strain gauges were placed on the

22、top and side surfaces of the beams in the longitudnal and the transverse directions as shown in figure 4. The figure also indicates the position of the linear voltage displacement transducers (LVDTs)which were used to measure deflexion at mid-span and at the loaded cross-sections.The measurements we

23、re recorded by an automatic computer-based data-logger (Solatron) capable of measuring strains and displacements to a sensitivity of2microstrain and0.002 ram, respectively.EXPERIMENTAL RESULTSThe main results obtained from the experiments together withinformation essential for a better understanding

24、 of beam behaviour are shown in figures 5 to 14. Figure 5 shows the uniaxial compression stressstrain relationships of the concrete used in the investigation, whereas figures 6 and 7 show the relationships between longitudinal and transverse strains, measured on the top surface of the beams (a) at t

25、he cross-sectionswhere the flexure cracks which eventually cause failure are situated (critical sections) and (b)at cross-sections within the shear span, respectively.Figures 6 and 7 also include the longitudinalstraintransverse strain relationshipcorresponding to the stress-strain relationships of

26、figure 5.Figure 8 shows the typical change in shape of the transverse deformation profile of the top surface of the beams with load increasing to failure and figure 9 provides a schematic representation of the radial forces and stresses developing with increasing load due to the deflected shape of t

27、he beams. Typical load-deflexion relationships of the beams are shown in figure 10, whereas figure 11 depicts the variation on criticalsections of the average vertical strains measuredon the side surfaces of the beams with the transverse strains measured on the top surface. Figure 12 indicates the s

28、trength and deformation response of a typical concrete under various states of triaxial stress and figure 13 presents the typical crack pattern of the beams at the moment of collapse. Finally, figure 14 shows the shape of the longitudinal stress distribution on the compressive zone of a critical sec

29、tion at failure predicted on the basis of the concepts discussed in the following section.中文翻譯 I：在多向應(yīng)力作用下從混凝土的特性看受彎鋼筋混凝土梁變化的一個基本試驗M. D. Kotsovos倫敦皇家科學(xué)與技術(shù)學(xué)院土木工程系本文所探討的問題是通常認為在荷載遞增下鋼筋混凝土結(jié)構(gòu)呈現(xiàn)彈性狀態(tài)， 這必須是因為混凝土的應(yīng)力 -應(yīng)變關(guān)系有一個逐漸遞減的臨界部分的真實性。試驗數(shù)據(jù)顯示受彎鋼筋混凝土梁會在受壓面的縱向壓應(yīng)變超出0.0035。這表明這些應(yīng)變是鋼筋混凝土結(jié)構(gòu)的本質(zhì)， 它是由于一個比極限強度小的復(fù)雜多向

30、的應(yīng)力狀態(tài)而不是塑性材料的特性引起的。 一個復(fù)雜應(yīng)力系統(tǒng)的存在為梁的狀態(tài)提供了一個基本試驗，而不是想象的一個現(xiàn)有設(shè)計過程。引言“剖面” 理論不僅是通常認為能很真實地描述鋼筋混凝土梁和預(yù)應(yīng)力混凝土梁在彎矩和軸向荷載下的變形， 而且能確切地闡述， 所以它提供了一個設(shè)計工具， 因為它的有效和簡單而聞名1 。假設(shè)在臨界橫截面?zhèn)蔷獾模@個理論分析地描述了一個梁的承載能力和幾何特性之間的關(guān)系。變形協(xié)調(diào)必須滿足 “水平橫截面荏苒水平”的假定和縱向混凝土和鋼筋的應(yīng)力是通過材料的應(yīng)力-應(yīng)變的特性來估算的。為了簡化計算，忽略橫向的應(yīng)力和應(yīng)變。受壓混凝土的應(yīng)力 -應(yīng)變特性認為能夠被混凝土試塊的變形充分地描述，例

31、如在極限的有限狀態(tài)下，棱柱體或圓柱體在橫截面的受壓區(qū)受單軸壓力和應(yīng)力， 就像現(xiàn)行規(guī)范所建議的CP1101，顯示出一個與圖 1 相似的形狀。 圖 1 表明縱向應(yīng)力隨著與中和軸的距離增加而增加至最大值，然后保持不變。 這個分布圖已經(jīng)達到安全性和受壓混凝土的應(yīng)力 -應(yīng)變關(guān)系的廣泛觀點，由上升和逐漸下降的兩部分組成 (如圖 2 所示)。超出極限的部分，材料的塑性應(yīng)力能力如圖1 所示，被認為對梁的最大承載能力有較大的作用。圖 1.臨界面破壞建議 CP 為 110 的應(yīng)力和應(yīng)變分布圖 2.受壓混凝土結(jié)構(gòu)的標準應(yīng)力-應(yīng)變關(guān)系然而，最近關(guān)于在集中力作用下的混凝土的變化的一個分析性調(diào)查表明，在壓應(yīng)力作用下混凝土

32、的極限強度變形沒有對所有被調(diào)查的結(jié)果形式的變化產(chǎn)生明顯的影響 (2,3) 。如果這個變化對任何結(jié)果都是典型的，那么在鋼筋混凝土梁的頂面被測的很大的壓應(yīng)變 (超出量 0.0035)在它的極限有限狀態(tài)下 (如圖 1)，不能對極限單軸應(yīng)力 -應(yīng)變特性產(chǎn)生作用。因此，因為壓應(yīng)變在單軸壓力下的任何混凝土的極限強度等級下為 =0.002( 如圖 2 所示) ，在混凝土的單軸應(yīng)力 - 應(yīng)變關(guān)系下降部分，將出現(xiàn)一個在荷載作用下梁變化的現(xiàn)在可行的預(yù)測。根據(jù)以上的觀點，本文的描述都在以下的評價中，廣泛的支持觀點的一個單軸應(yīng)力- 應(yīng)變關(guān)系由一個上升的和一個逐漸下降的部分組成，對受彎的根據(jù)混凝土梁的變化的真實描述是非

33、常必要的。 這個結(jié)果是從梁在兩點荷載作用下彎曲得到，表明很大的應(yīng)變的通過梁受壓的混凝土呈現(xiàn)的，由于三維應(yīng)力而不是一味的混凝土極限應(yīng)力 - 應(yīng)變特性。這表明材料本身受到一個完整和直接的承載能力損失，當極限強度被超過的假定與彈性結(jié)構(gòu)的變化并存的，通過偏心荷載或瞬間旋轉(zhuǎn)關(guān)系表明的。試驗細節(jié)試塊三根矩形鋼筋混凝土梁，跨度 915mm，橫截面為 102mm51mm，受剪區(qū)跨度為 305mm(如圖 2 所示)。受力筋由兩個直徑為 6mm，屈服荷載為 11.8kN 的鋼筋組成。在梁端部鋼筋彎起， 就能為整個受剪跨度提供抗力。 整個受剪跨度內(nèi)壓縮張拉的加強筋布置了七個直徑為3.2mm 的箍筋。在梁的中間部分沒

34、有壓縮加強筋和箍筋。根據(jù)上面所述的鋼筋布置， 所有的梁都是受彎破壞而不是受剪破壞， 盡管剪跨比為 3。所有的梁與受控的試塊一起放在20 o C 的濕麻袋下七天， 然后貯存在實驗室條件下 (20 o C ,40%濕度)2 個月，直到試驗結(jié)束。所有混凝土配料都在表格I 中。試驗過程通過液壓錘和分布梁加載，每次大約增加0.5kN。為了測量荷載和試塊的形變，每次持荷約 2 分鐘。荷載用一個荷載單元來測量， 形變由 20mm 長的電阻應(yīng)變片和位移轉(zhuǎn)換器測得。應(yīng)變片貼在梁縱向和橫向的頂面和側(cè)面(如圖 4 所示)。圖 4 也表明了直流電壓位移轉(zhuǎn)換器（LVDT S）的位置，它是用來測量跨中和加 載橫截面的形變

35、。測量數(shù)據(jù)記錄在計算機自動數(shù)據(jù)記錄儀中， 能夠測量應(yīng)變和形變的靈敏度分別為 2 微應(yīng)變和 0.002mm。試驗結(jié)果主要的試驗結(jié)果是從試驗中得到的， 能更好地了解梁的變化， 所示圖 5 至圖14 的信息是必不可少的。圖 5 表明結(jié)果的單軸壓應(yīng)力 -應(yīng)變關(guān)系應(yīng)用于調(diào)查中， 而圖 6 和圖 7 表明縱向應(yīng)變與橫向應(yīng)變的關(guān)系，分別位于(a)彎曲裂縫最終導(dǎo)致破壞橫截面出和 (b)受剪區(qū)跨內(nèi)的橫截面出。圖 6 和圖 7 也包含了縱向應(yīng)變 -橫向應(yīng)變與圖 5 的應(yīng)力-應(yīng)變關(guān)系是一致的。圖 8 中標準的改變在梁頂面的橫向形變輪廓圖中和圖9 提供一個軸力和應(yīng)力隨著荷載的增加而增大， 導(dǎo)致梁向下變形的圖框表示方法

36、。 梁的標準偏心荷載關(guān)系如圖 10 所示，而圖 11 描述了測得平均豎向應(yīng)變的梁側(cè)面的臨界截面變形和橫 向應(yīng)變在頂面測得。圖 12 中標準結(jié)果的強度和形變在各種狀態(tài)的十三軸應(yīng)力下河圖 13 所呈現(xiàn)的梁標準裂縫圖樣在破壞的瞬間。 最后圖 14 表明在臨界截面的受壓區(qū)傷縱向應(yīng)力的分布形狀，可根據(jù)概念來預(yù)測破壞，在以下部分將被討論。圖 3.梁的細節(jié)外文原文 II:Some questions on the corrosion of steel in concrete.Part : Corrosion mechanism and monitoring, service life prediction

37、and protection methodsJ.A. Gonzdlez , S. Felifd, .PRodffguez , W. Lfpez , E. Ramlrez , C. Alonso , C. AndradeABSTRACTThis second part addresses some important issues that remain controversial despitethevastamountsofworkdevotedtoinvestigatingcorrosionin concrete-embeddedsteel. Specifically,these refe

38、r to: 1) the relative significance of galvanic macrocouples and corrosion microcells in reinforced concrete structures; 2) the mechanism by which reinforcements corrode in an active state; 3) the best protective methods forpreventing orstopping reinforcement corrosion; 4) the possibility of a reliab

39、le prediction of the service life of a reinforced concrete structure ; and 5) the best corrosion measurement and control methods. The responses provided are supported by experimental results, most of which were obtained by the authors themselves.INTRODUCTIONConcrete-embeddedsteel is known to remain

40、in apassive state under normal conditions as a result of the highlyalkaline pH ofconcrete. The passivity of reinforcements ensures unlimited durability of reinforced concrete (1KC) structures. However, there are some exceptional conditions that disrupt steel passivity and cause reinforcements to be

41、corroded inan active state. This has raised controversial interpretations, some of which were discussed in Part I of this series 1. This Part II analyses though far from exhaustively, other - to the authors minds at least - equally interesting issues on which no general consensus has been reached.MA

42、TERIALS AND METHODSThe reader is referred to Part I for a detailed description of the materials and methods used in this work. Most of the experimental results discussedherein were obtained withthe same types of specimens and slabs.Galvanic couples were determined on speciallydesigned specimens, suc

43、h as those shown in Figs. 1 and 2.Near-real conditions were simulated by using a beam that was 160cm long and 7 x 10 cm in cross-section. The beam was made from 350 kg cement/m 3, half of which contained no additives, while the other half included 3% CaC12 by cement weight 2, (Fig.1). Inorder to stu

44、dy the effect ofthe Sanod/Scathoa ratio on galvanic macrocouples, they were modelled by surrounding a small carbon steel anode with a stainless steel (AISI 304) cathode and vice versa(Fig. 2). In this way, the ratios consistensy was assured. In addition, the potential and icorr of stainless steal an

45、d those of the passive structures were very similar.Fig. 1 - Beam used to measure icoTr and Ecorr inFig. 2 -Scheme of galvanic macrocouples embedded concrete with and without chlorides and toin chloride- containing mortar used to study the illustrate the significance of passive steel/activeeffect of

46、 the Sanod/Scathodratio and their relative steel macrocouples.significance to corrosion microcells.RESULTS AND DISCUSSIONWhat is the relative significance of galvanic macrocouples and corrosion microcells in RC structures ?According to several authors 3, 5, the polarization resistance method provide

47、s an effective means for estimating the corrosion rate of steel in P,C ; the method is quiterapid,convenient,non-destructive,quantitativeandreasonably precise. However,itisuncertainwhetheritmaygiverisetoserious errorswith highly-polarized electrodes by the effect of passive/active area galvanic macr

48、ocouples in the reinforcements 6.Based on the authors own experience with the behaviour of galvanic macrocouples in PC, the contribution of these macrocouples to overall corrosion is very modest rehtive to that of the corrosion microcells formed in the active areas of reinforcements in the presence

49、of sufficient oxygen and moisture 2, 7, 8. Thus, it has been experimentally checked that:Galvanic macrocouples have a slight polarizing effect on anodic areas in wet concrete, whose potential is thereby influenced in only a few millivolts.On the other hand, macrocouples have a strong polarizing effe

50、ct on passive areas despite the low galvanic currents involved relative to the overall corrosion current.As a result, galvanic currents can result in grossly underestimated icorr values for the active areas since they are often smaller than 10% of the ico= values estimated from polarization resistan

51、ce measurements.The corrosive effect ofcoplanar macrocouples on RC structures only proves dangerous within a small distance from the boundary of active and passive areas.Fig. 3 compares the estimated icorr and ig values, in mortar containing 3 o A CaC12,per anode surface unit for a number of anode/c

52、athodesurface ratios for AISI 304 stainless steel/carbon steel macrocouples in support of the above conclusions 9.By what mechanism do reinforcements corrode in an active state ?When the passive state is lost, the rate of reinforcement corrosion in inversely proportional to the resistivity of concre

53、te over a wide resistivity range 10. BecauseFig. 3 - Relative significance of corrosion microcellsFig. 4- Trends in ico. and Ecorr for (icorr) and galvanic macrocouples (i.) in corrosionspecimens exposed to an oxygen-freeof steel embedded in mortar containing no chloride.environment.Both currents we

54、re calculated relative to Sanod (carbon steel in the macrocouples of Fig. 2).the environments relative humidity and ionic additives of concrete determineconcrete resistivity, these factors, together with oxygen availability at reinforcement surfaces,control the corrosion rate 11.The electric resisti

55、vity of water-saturated concrete structures is relatively verylow, and the corrosion rate is believed to be essentially controlled by the diffusion of dissolved oxygen through the concrete cover up to reinforcements. This is consistent with the widespread belief that the sole possible cathodic react

56、ion in neutral and alkaline solutions is oxygen reduction.The significance ascribed to the role of oxygen justifies the efforts to determine its diffusion coefficient in concrete12, 13. The variety of methods and experimental conditions used for this purpose have led to a wide range of diffusivity v

57、alues (from 10 -12 to 10 -8 m2/s) for oxygen incement paste 14.Since the diffusion coefficient of oxygen in aqueous solutions (1)O2 = 10 -5 cm2/s-1), is saturation concentration (CO2 = 2.1 x 10 -7 mol/cm 3) and the approximate thickness of diffusion layers in stagnant solutions (8 = 0.01 cm) are wel

58、lknown, the limiting diffusion current can be calculated as :ilo2 = - z FD02C02/r = 8 x 10 -4 A/cm 2 (80 pA/cm 2)where z is the number of equivalents per mole (4) and F the Faraday (96,500 A.s/eq).For 1-cm thick mortar covers of average porosity 15%(see Fig. 1 in Part I) 1 and a diffusioja layer thi

59、ckness of the same order as the cover thickness, 11o2 = 0.12 laA/cm 2, which is quite consistent withthe icorr values estimated under pore saturation conditions at the end of the curingprocess, both for mortars containing no chloride ions and for those including 2, 4 or 6% C1- 16.On the other hand,

60、icorr values of ca. 10 liA/cm 2 (see Fig. 9 in Part I) 4 have been obtained by several authors for mortars with chlorides or carbonated mortarswhich are incompatible with the rates allowed by the limitingdiffusion current of oxygen. Therefore, in some circumstances, alternative cathodic processes al