毕业论文外文翻译-随时间变化的钢筋混凝土阻力分析.doc

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1、附件1：原文随时间变化的钢筋混凝土阻力分析摘要对钢筋混凝土材料时间相关性的分析方法进行介绍，讨论钢筋混凝土的作用机理，然后再研究随时间而定的钢筋混凝土抵抗力。此外，钢筋混凝土结构中的钢材腐蚀也是需要被分析的。鉴定随时间而变的抵抗力的实际统计方法，包括物质的材料，结构尺寸，影响计算的确定。另外，范例中估计随时间而变钢筋混凝土结构构件的抵抗力是给的。关键字不定分析 ；随时间变化的抵抗力；钢筋混凝土1介绍：因为钢筋混凝土材料适用于很多地方，并且价格便宜，所以它在土木工程中是一种非常有用的材料。因此，这种材料大量的被使用。然而，传统的建筑结构设计和钢筋混凝土材料的研究很少注意到钢筋混凝土强度和时间的关

2、系，尤其是作用在材料上的不同影响作用几乎是不予研究的。直到近年来，在建筑施工中的一些研究才涉及这个问题关于钢筋混凝强度与时间相关性的。已做过的关于钢筋混凝土柱破坏概率的研究表明低强度的钢筋混凝土柱破坏概率低于偶然的荷载作用下的破坏概率。并且这种计算方法已经被运用到随时间而变化的破坏概率的计算上。低强度的和Liu4 混凝土结构耐久性上的研究认为这种作用加速了其的破坏。并且Lu 6等已经论述钢筋腐蚀的情况。一般而言，依赖不同因素的钢筋混凝土抵抗力明显减小。在对混凝土结构安全性校核上,基础理论为钢筋混凝土耐久性分析提供了建议。研究随时间而变的钢筋混凝土结构的性质的是必要的。影响钢筋混凝土机理的因素

3、许多因素对钢筋混凝土抵抗力都产生影响。在水区域内存在着超过50种化学腐蚀元素,水在其中工作并且起调节作用。获得一次相关钢筋混凝土模型的实际方法是一种多因素理解方法。通常，对于单一的因素，许多结果只考虑到混凝土的碳化作用，碳化的厚度可以用下面公式来表示：可以写为：D ( t) = K t (1)式中D ( t)，K和t分别为厚度，速度系数与碳化的时间。到目前为止，虽然有许多模型被运用到钢筋的断裂，疲劳破坏中，但是还没有大家都认可的结论存在。一般而言，能够降低钢筋混凝土的抵抗力的变量有钢筋的几何尺寸，周边环境情况以及随时间而变的抵抗力等。显而易见，钢筋混凝土抵抗力的变化是的一个随机函数过程或者说是

4、一系列材料和结构变量的相互作用。钢筋混凝土在空气中的碳化被称之为中和反应。它是合成物与在空中的CO2以及钢筋混凝土中的碱性材料缓慢中和的过程。在空气中完全地碳化密实混凝土中的钢筋保护层需要花费几十年的时间，但是碳化非密实混凝土的只要几年。如果稀薄的碳化材料的含量比较高，则钢筋混凝土强度就会下降并且在碳化过程中结构的横截面也会加快缩小。碳化作用会造成碱度的降下和钢筋的腐蚀。钢筋腐蚀是钢筋表面中的铁不断地失去电子然后在溶于水，再在有氧的条件下与水发生反应。所以，消耗几倍时间大量的浸蚀材料。这样可以使产生钢筋混凝土保护层产生裂缝，并且沿着钢筋方向降低钢筋与混凝土之间的粘结力，从而造成钢筋混凝土结构承

5、载能力的损失。近来的研究表明钢筋最严重的腐蚀是非碳化保护层15mm处。另一方面,由于不完善的表层和在混凝土上的裂缝，使腐蚀的开始时间可能会提前，并且腐蚀速度也可能大大地提高。当钢筋应力小于其屈服点时，其破坏速度是固定的。但是当钢筋应力超过屈服点时，破坏速度将提高几倍。后者被称为应力破坏，它是脆性的和危险的体现。钢的锈蚀会减小钢筋的承压面积，破坏粘结力以及降低结构的有效性。空气的腐蚀以及所有的液体都会对钢筋混凝土产生巨大的影响。它们会造成钢筋混凝土的腐蚀，混凝土保护层厚度的减少，最终加快钢筋的锈蚀。当结构承担活荷载时，钢筋混凝土结构产生疲劳破坏,造成强度极限和刚度的递减，而且使其产生并且扩大裂缝

6、。通常疲劳破坏可以被分为固定和随机破坏，前者被用来决定荷载周期，而后者相对于任意的材料和荷载而言。除以上所述外，还有其他许多因素对其有影响。例如温度（包括温度的高低，变化周期，冻害, 湿度（包括干湿周期），以及荷载的调幅。荷载的调幅可以使钢筋混凝土结构的抵抗力降低。3任意时间相关性分析属于该情况结构的随机变量是彼此相互独立的,并且认为随时间变化为特征的材料，以随机时间相依函数为特征的钢筋混凝土可以用下面公式来表示： 式中：这一随机变量指出了结构材料与试验材料性质的差异；是建筑试验材料性质的差异系数，是试验材料的随机变量。根据统计理论，平均值和标准自差系数 （3） 式中表示平均值，表示随机过程的

7、标准自差系数 , 和 分别 是试验材料性质的平均值和自差系数标准以及随机变量 。同样地，任意与其类似的解析模型多半可以认为，用来研究任意随时间变化的钢筋混凝土结构的几何参数和计算方法。同样地，与其类似的分析模型的随时间变化的钢筋混凝土结构的几何参数和计算方法多半可以这样来研究。钢筋混凝土的抵抗力可以用抵抗力函数R ( x1 , x2 , , xn )表示。其中 表示计算结构的参数，例如材料，几何形状，计算方法等。另外，考虑到疲劳工作，计算模型和最初参数以及与时间相关的抵抗力模型可以用下式表示： 式中 ： (R0, t) 是随机抵抗过程，R0 是最初阻力，,是随机过程的疲劳破坏，Kp是计算模型的

8、不可测定参数，xi表示随机过程的物质参数。许多关于钢锈蚀的实验表明钢的侵蚀过程与正规随机过程相一致。分离程序，随机时间相关的抵抗力( R0, t)可以简单地表示为: 式中：R ( t)是由时间决定的函数，而R0是任意初阻力。另外，其它的不能确定的情况应该被考虑 ，例如未确定实际材料的抵抗力大小，几何学尺寸，和计算模型。对于简单结构，任意过程的抵抗力函数， 可以简单写成： 式中：是与时间有关的函数，计算模型是计算模型的不可测定参数，以及是由计算模型决定的结构抵抗力。 对于单一结构构件用等式( 7)表示，可以写作： 式中：,以及分别表示为随时间变化的计算参数，钢筋混凝土结构构件几何形状和材料的特征

9、。是材料抵抗力标准值。平均值和标准偏差等式( 8)分别如下式表示： 在具体施工应用中，混凝土结构阻力随机过程的递减函数按以下公式计算： 式中的是混凝土结构阻力的随机过程，, 是相关的随机变量，以及 是随时间变化的函数。基于混凝土结构设计的耐久性等级，等式（11）可以采用下列公式确定： 式中当钢筋混凝土达到极限时混凝土的抵抗力平均值；当钢筋混凝土达到极限时钢筋的抵抗力平均值；钢筋混凝土中的混凝土的标准偏差系数；钢筋混凝土中的钢筋的标准偏差系数；，分别为混凝土和钢抵抗力减小系数，; ，涉及到结构的材料，可以从材料实验中获得； 工程应用测试轴向受压钢筋混凝土的结构构件，从而得到一些结构阻力的统计资料

10、。考虑初始值C30 的混凝土的平均值，标准偏差；;20MnSi的钢筋，平均值，偏差标准偏差; 初始阶段的尺寸是。混凝土和钢的抵抗力减小系数可以分别从Ref 4处获得，。在这种条件下，轴向受压的钢筋混凝土结构相关随机时间抵抗力可以从中获得。根据钢筋混凝土结构的设计理论，抵抗力函数，式中和分别为混凝土和钢筋的初阻力。其次在论文中使用该理论建议，来计算随机时间而定的抵抗力。一些统计数据见表格1。从计算结果中可以清楚的看到，钢筋混凝土的阻力明显地随时间增加而减小。这个现象是重要，并且在校核钢筋混凝土的安全性上是不能忽略的。表1 轴向受压的钢筋混凝土结构构件随时间变化的抵抗力时间/年0102030405

11、0平均值kN762520732395713656688575651744598732标准偏差kN124863119380116473112949108028101105变化系数0163701629016320164001657016885 结论 对于土木工程的研究，设计，建设，钢筋混凝土结构的特征是非常重要的。任意随时间变化的钢筋混凝土材料的研究对于结构测试，钢筋混凝土结构的养护，安全评估是必需的。为了结构可靠性的设计，任意随时间变化的实际抵抗力应该被确定。 在论文里针对以材料为特征钢筋混凝土进行研究，其中对混凝土产生影响的因素有混凝土碳化，钢筋腐蚀。针对随时间而变钢筋混凝土结构的抵抗力，影响

12、钢筋混凝土的其他因素和解析方法是被建议的。附件2：外文Time-varying resistance of reinforced concreteAbstract: Reinforced concrete analysis of the correlation time are introduced, discussed the mechanism of reinforced concrete, and then study with time-dependent resistance of reinforced concrete.In addition, steel reinforced c

13、oncrete structure also needs to be analysis of the corrosion.Identification of resistance to change over time the actual statistical methods, including physical materials, structure size calculation to determine impact.In addition, the sample estimated change over time the resistance of reinforced c

14、oncrete structures is given.Keywords: uncertainty analysis; resistance over time; reinforced concrete1.Description:Because reinforced concrete material used in many places, and the price is cheap, so it is a very useful in civil engineering materials.Therefore, a lot of this material is used.However

15、, the traditional structural design and construction of reinforced concrete reinforced concrete little attention to the relationship between intensity and time, especially the role of the different effects of the material is almost no study of the role.Until recent years, several studies in building

16、 construction was related to this issue - on the strength of reinforced concrete and time-related nature.Has been done on reinforced concrete columns of the failure probability that low-intensity failure probability of reinforced concrete columns under load than accidental damage probability.And thi

17、s method has been applied to changes over time, the failure probability calculation.Low intensity and Liu 4 research on the durability of concrete structures that this effect accelerate its destruction.And Lu 6, have already discussed the case of steel corrosion.In general, rely on different factors

18、 significantly reduced the resistance of reinforced concrete.In checking on the safety of concrete structures, the basic theory for the durability of reinforced concrete to provide recommendations.Of change over time the nature of reinforced concrete structures is necessary.2.Factors that affect the

19、 mechanism of reinforced concreteMany factors have an impact resistance of reinforced concrete.Memory in the water area more than 50 chemicals in the corrosive elements, water, work and play in which the regulatory role.Reinforced concrete model to obtain a related approach is a practical understand

20、ing of multi-factor approach.Typically, for a single factor, many of the results only take into account the effect of concrete carbonation, carbonation thickness can be expressed using the following formula:Can be written as: D (t) = K t (1)Where D (t), K and t are the thickness, the speed factor an

21、d carbonization time.So far, although many models have been applied to the reinforcement of the fracture, fatigue failure, but has not accepted the conclusions of all existence.In general, to reduce the resistance of reinforced concrete reinforcement geometry variables, the surrounding environment a

22、s well as resistance to change over time and so on.Clearly, resistance to change is reinforced concrete, a random function or set of materials, processes and structure of variable interactions.Reinforced concrete carbonation in the air is called in and response.It is complex and CO2 in the air as we

23、ll as the basic material of reinforced concrete and in the slow process.Carbonation in the air fully dense protective layer of reinforced concrete will take decades, but the non-compacting concrete carbonation as long as several years.If the thin material with high content of carbon, the strength of

24、 reinforced concrete will drop and the structure in the carbonization process will speed up the narrow cross-section.Carbonation can cause lowering of alkalinity and steel corrosion.The surface of the steel reinforcement corrosion of iron is steadily losing its electronic and then in water, and then

25、 under the conditions in the aerobic react with water.Therefore, the consumption of time many times a lot of erosion materials.This allows the production of reinforced concrete protective layer cracks, and along the direction of Jiangdi Gangjin the bond between steel bars and concrete strength, rein

26、forced concrete structure, resulting in the loss of carrying capacity.Recent studies suggest that the most serious corrosion of non-reinforced carbon protective layer 15mm place.On the other hand, due to imperfections on the surface and the cracks in the concrete, so that corrosion may be ahead of t

27、he start time, and the corrosion rate may be greatly increased.When the steel stress is less than the yield point, the damage rate is fixed.But when the steel stress exceeds the yield point, the damage rate will increase several times.The latter is known as stress fracture, which is brittle and dang

28、erous embodiment.Corrosion of steel reinforcement will reduce the pressure area, destroy the structure of bond strength and reduced effectiveness.Corrosion of the air and all of reinforced concrete liquid will have a huge impact.They can cause corrosion of reinforced concrete, concrete cover thickne

29、ss reduction, and ultimately accelerate the corrosion of steel.When the structure bear live loads, fatigue of reinforced concrete structures destroyed, causing the ultimate strength and stiffness of the decline, Erju and expanded to produce cracks.Fatigue failure usually can be divided into fixed an

30、d random destruction, the former was used to determine the load cycle, while the latter relative to the terms of any of the materials and loads.Apart from the above, there are many other factors affecting them.For example, temperature (including temperature, height, change cycle, frost, humidity (in

31、cluding wet and dry cycles), and the load amplitude.AM loading can reduce the resistance of reinforced concrete structures.3.Any time correlationThe structure of the situation is a random variable is independent of each other, and that over time the material is characterized by random time-dependent

32、 function characteristics of reinforced concrete that can use the following formula:Where: The structure of the random variable that material properties of materials and test the difference;The nature of building test materials is different coefficient of random variables to test the material.Accord

33、ing to statistical theory, the mean and standard deviation coefficient of self-(3)Where indicated, on average,Since the random process that the standard deviation coefficient, Respectively, to test the material properties and the mean and standard deviations of coefficients and random variables.Simi

34、larly, any analytical model to its most similar to that used to study any time-varying geometric parameters of reinforced concrete structure and method of calculation.Likewise, a similar analysis model with time-varying geometric parameters of reinforced concrete structures and computational methods

35、 to study the most can be.The resistance of reinforced concrete resistance function can be R (x1, x2, , xn) said.Which expressed the calculation of the structure parameters, such as materials, geometry, calculation methods.In addition, taking into account the fatigue of work, and the initial model p

36、arameters and model with time-related resistance can be expressed as follows:Where: R (R0, t) is a random process of resistance, R0 is the initial resistance, is a random process of fatigue failure, Kp can not be measured to calculate the model parameters, xi random process that the material paramet

37、ers.Many experiments show that the corrosion on the steel corrosion process of steel is consistent with the regular random process.Separation process, random time-dependent resistance R (R0, t) can be simply expressed as:Where: R (t) is determined by the time function, and R0 is an arbitrary initial

38、 resistance.In addition, other circumstances can not be determined should be considered, for example, the resistance of materials determined the actual size, geometry, size, and computational models.For simple structures, the resistance function of any process, you can simply write:Where: is the tim

39、e-related functions, calculation model is to calculate the model parameters can not be measured, and the model determined by the structure of resistance.For a single structural component with equation (7) that can be written as: Where:, and, respectively, for the calculation of parameters over time,

40、 reinforced concrete structural geometry and material characteristics.The material resistance to the standard value.Mean and standard deviation of equation (8), respectively, be expressed as follows: In the specific construction applications, the resistance of concrete structures decreasing function

41、 of random process in the following formula:Where is the resistance of the random process of concrete structures, is related random variables, and is a function of change over time.Durability design of concrete structures based on rank, equation (11) can be determined using the following formula: Wh

42、ere - when the reinforced concrete to reach the limits of the average resistance of concrete;- When the reinforced concrete resistance to limit the average;- Reinforced concrete in the standard deviation coefficient of concrete;- Reinforced concrete are the standard deviation coefficient;, Respectiv

43、ely, decreased resistance of concrete and steel factor;, related to the structure of the material, the experiment can be obtained from the material;4 ApplicationAxial compression tests of reinforced concrete structural members, resulting in some structural resistance statistics.Consider the initial

44、value:C30 concrete in the mean, standard deviation; 20MnSi reinforcement, the average deviation of standard deviation; the size of the initial phase is.Resistance of concrete and steel, respectively, from the reduction factor to Ref 4 obtained.Under these conditions, the axial compression of the rei

45、nforced concrete structure can be related to resistance to derive random time.According to the design of reinforced concrete structure theory, the resistance function, where and are the initial resistance of concrete and steel.Secondly, the paper proposed to use the theory to calculate the random ti

46、me-dependent resistance.Some statistics, see Table 1.From the results can clearly see that the resistance of reinforced concrete with time significantly increases.This phenomenon is important, and in checking on the safety of reinforced concrete can not be ignored.Table 1, the axial compression of t

47、he reinforced concrete structural resistance to change over timeTime / year 01,020,304,050Average / kN 7625.20 7323.95 7136.56 6885.75 6517.44 5987.32Standard deviation / kN 1248.63 1193.80 1164.73 1129.49 1080.28 1011.050.1637 0.1629 0.1632 0.1640 coefficient of variation 0.1657 0.16885 Conclusion For civil engineering research, design, construction, characteristic of reinforced concrete structures is very important.Any change over time of reinforced concrete for structural testing, reinforced con