土木工程外文翻译.doc

英文翻译1外文原文出处：ACI Structural Journal; Nov/Dec2009, Vol. 106 Issue 6, p858-867, 10p, 2 Diagrams, 4 Charts, 6 Graphs.Gholamreza Fathifazl, A. G. Razaqpur, O. Burkan Isgor, Abdelgadir Abbas, Benoit Fournier, and Simon Foo.USA再生骨料生产的钢筋混凝土梁的抗弯性能一种混合配制新方法被用于检测以粗再生混凝土骨料(简称RCA)制成的钢筋混凝土梁的弯曲性能，在这个方法中，RCA被视为由剩余砂浆和天然骨料两种材料组成的混合物；然而，当它以一定比例混合时，每个阶段的含量和性质就应该被分开来考虑。几种钢筋混凝土梁的制作和测试过程都是采用了混凝土混合物设计的新方法，比如他们的挠度；开裂时刻，屈服时间，最终时刻；裂缝间距，开裂模式和失效模式等方面都还在研究中。调查结果显示，在适用性和承载能力极限状态两方面表明，用RCA混合配制新方法制造的混凝土梁的抗弯性能要比传统的混凝土梁还好。一般的弯曲理论和当前有关弯曲设计的规定是可行的，该规定对再生钢筋混凝土梁不进行任何的更改。关键字：弯曲强度；混合物比例；钢筋混凝土；可操作性能；废物管理。 简介尽管经济和环境因素有利于用再生混凝土骨料(简称RCA)作原料的RCA混凝土的生产，但是建筑业已不能容纳它,特别是在结构应用性方面，部分原因正如以前的研究结论所说的那样，RCA混凝土从本质上来说比用天然骨料制造的常规混凝土差一点。在过去，混合物配制新方法在常规混凝土原料上所做的修改，就是用来设计RCA混凝土混合物的。主要修改就是增加了水泥量，但没有考虑RCA混凝土的剩余灰浆体积分数。虽然在水泥量、水灰比(w/c)以及RCA混凝土的混合比例方面做了适当的调整，所造出的混凝土比最早先生产的RCA混凝土具有更高的抗压强度。尽管如此，这种调整并没有使得RCA混凝土比常规混凝土拥有更优越的弹性模量、粘结强度或应力-应变性能。因此,报道称由RCA混凝土组成的结构构件会体现出较大的变形，更大的裂缝宽度和更小的裂缝间距，并且与常规混凝土构件相比有更低的抗弯强度。这种变化的缺点妨碍了其使用功能，因为它造成了RCA混凝土结构在适用性和持续性使用功能中的不确定因素。为了克服这一问题，有人单独进行了一项调查，其中详细介绍了一项新的RCA混凝土混合物配制方法，被称为等效砂浆体积法（简称EMV法）。在这个方法中，把RCA作为一种由剩余砂浆和天然骨料组成的两阶段复合材料；所以，按比例配制RCA混凝土时，每阶段材料含量不同也对应有不同的产物。由于用EMV方法配制成的RCA混凝土不会出现像用常规方法配制的RCA混凝土本质低劣这个问题。但假设这个说法是合理的，那么用RCA方法制成的混凝土构件不会产生较大的偏转以及较低的极限抗压强度，这与完全用天然骨料制成的常规钢筋混凝土构件具有类似的性质。为了验证这个假定，而进行了广泛的实验研究，通过测试弯曲作用下一定数量的RCA混凝土梁以及起控制作用的梁，仅天然粗骨料与RCA混凝土中的天然骨料类似。调查的几个因素包括挠度，裂缝间距，开裂时刻，屈服时刻，最终的抗弯强度，开裂模式和失效模式。在这研究中使用了两种不同来源的材料，他们所配制出的RCA-M混凝土和RCA-V混凝土是用于研究的，这些材料是分别在蒙特利尔（M）和温哥华（V）的再生混凝土加工厂里获得的。RCA-M混凝土中的天然骨料是天然石灰石，而在RCA-V混凝土中所用的却是天然的河床砂石。 英文原文1Flexural Performance of Steel-Reinforced Recycled Concrete Beams Gholamreza Fathifazl, A. G. Razaqpur, O. Burkan Isgor, Abdelgadir Abbas, Benoit Fournier, and Simon FooACI Structural Journal; Nov/Dec2009, Vol. 106 Issue 6, p858-867, 10p, 2 Diagrams, 4 Charts, 6 GraphsA new method of mixture proportioning is used to investigate the flexural performance of reinforced concrete beams made with coarse recycled concrete aggregate (RCA). In this method, RCA is treated as a two-phase material comprising residual mortar and natural aggregate; therefore, when proportioning the mixture, the relative amount and properties of each phase are considered separately. Several reinforced concrete beams are built and tested using concrete mixtures designed by the new method and their deflection; cracking, yielding, and ultimate moments; crack spacing; cracking patterns; and failure modes are studied. The results show that at both the serviceability and ultimate limit states, the flexural performance of beams made of RCA-concrete proportioned by the new method is comparable to that of beams made of conventional natural aggregate concrete; and the general flexural theory and current code provisions for flexural design are applicable, without alteration, to the reinforced recycled concrete beams.Keywords:flexural strength;mixture proportioning;reinforced concrete;serviceability;waste management.INTRODUCTIONDespite the economic and environmental benefits of concrete produced with recycled concrete aggregates (RCA)1 dubbed RCA-concrete, the construction industry has not embraced it, especially for structural applications, partly due to previous findings that have concluded that RCA-concrete is inherently inferior to conventional concrete made with natural aggregates.2 In the past, mixture proportioning methods for conventional concrete have been applied with minor modifications to design RCA-concrete mixtures. A principal modification has been the increase in the cement content, with no special consideration given to the residual mortar volume fraction of RCA.3 Although by suitable adjustment of the cement content and water-cement ratio (w/c) of mixtures involving RCA, concrete with higher compressive strength than the concrete from which the RCA originated has been produced,3 such adjustments have not resulted in comparable RCA-concrete possessing superior elastic modulus, bond strength, or stress-strain characteristics to similar grade conventional concrete.2,4 Consequently, it has been reported that structural members made from RCA-concrete experience larger deflection, exhibit wider cracks and smaller crack spacing, and have relatively lower flexural strength compared to the companion conventional concrete members.5 This kind of variability constitutes a drawback and discourages its use because it creates uncertainty with respect to the serviceability and long-term performance of RCA-concrete structures.To overcome this problem, in a separate investigation,described in detail elsewhere, the authors developed a new mixture proportioning method for RCA-concrete called the equivalent mortar volume (EMV) method.6 In this method, RCA is treated as a two-phase composite material comprising residual mortar and original natural aggregate; therefore, when proportioning a concrete with RCA, the volume fraction and relevant property of each phase is accounted for. Because an RCA-concrete mixture proportioned by the EMV method does not suffer from the inferiorities of RCA-concrete proportioned by conventional methods, it is reasonable to assume, contrary to previous findings, that reinforced concrete members made of RCA-concrete thus proportioned will not experience larger deflection and lower ultimate flexural strength compared to reinforced concrete members produced with similar grade conventional concrete made entirely with natural aggregates.To verify this assumption, an extensive experimental study was carried out by testing under flexure a number of reinforced RCA-concrete beams made with coarse RCA and companion control beams made of concrete containing only coarse natural aggregate with similar properties as the coarse natural aggregate in RCA. The investigated properties include deflection, crack spacing, cracking moment, yielding moment, ultimate flexural strength, cracking pattern, and failure modes. Two different sources of RCA, designated RCA-M and RCA-V, were used in the study and are obtained from recycled concrete processing plants in Montreal (M) and Vancouver (V), respectively. The natural aggregate in RCA-M was natural limestone, whereas that in RCA-V was natural river-bed gravel. Further details on the characteristics of the RCA used in this study can be obtained from Fathifazl.英文翻译2外文原文出处：International Journal of Applied Science, Engineering and Technology 5:4 2009.Nasim Shatarat and Adel Assaf .USA.分析多跨简支预制桥梁的抗震性能和要求1.介绍华盛顿州在1950年和1960年期间所建造的桥梁一般都采用多跨简支（简称MSSS）预制系统。这个系统被科学家们证实,在当时是易于设计和建造桥梁的。设计师们使用预先设计的一整套部件，上层建筑和下部结构组件的选择是基于对某些全球性桥梁的特点和桥梁的尺寸来的，如柱子的高度，桥梁路面宽度，弯曲偏斜和跨度桥梁。由此，地基条件或其他组件的改变可能是因为引入了地质条件。这些桥梁的上层建筑包括支承于混凝土桥墩上的混凝土梁，桥墩通常是一根3英尺4.5英尺（0.91米1.37米）大的横梁，一般靠很多3英尺（0.91米）长的圆柱支承着。而柱子的数量取决于桥的倾斜量及路面宽度，扩展基础或桩地基都是过去共同使用的基础系统。 华盛顿州1960年间在多跨简支预应力混凝土桥梁的设计思路中，很少或者说根本没有注意到地震力。抗震规范规定一定要保证适当的延展性和合理的抗震性能，比如钢筋闭合长度、搭接长度和梁支座长度可以不予考虑，只有一组梁是用来抵抗支承桥面发生横向运动的。纵向位移基本不常见，主梁和梁帽上方的接触长度假定足够承担纵向位移。承台是一种常用的支座，支承在条形基础或深基础上。最近，华盛顿州交通部（简称WSDOT）全面将地震分析程序投入使用，用以评估现有桥梁在地震危害中的薄弱点，并确定最有效的改造方案。这项研究调查的多座多跨简支预制桥中，其中具有代表性的一座坐落在华盛顿州。这座桥建于20世纪60年代,在1979年和2001年桥面先后拓宽了两次。这一研究项目的主要目的是，确定桥梁在地震中的薄弱点，因而可以大力发展改进措施。桥梁的地震薄弱性进行评估使用的两个地震评价方法，是联邦公路管理局（简称FHWA）在公路桥梁抗震加固改造手册中所提出，就是方法C和方法D2。 英文原文2Seismic Behavior and Capacity/Demand Analyses of a Simply-Supported Multi-Span Precast BridgeNasim Shatarat and Adel Assaf International Journal of Applied Science, Engineering and Technology 5:4 2009I.INTRODUCTIONACOMMONLY used type of bridges in Washington State (WA) in the 1950s and 1960s is Multi-Span-Simply-Supported (MSSS) precast system. This system was proven at the time to be easy to be designed and to be constructed. The designers used a pre-designed tabulated set of bridge components, where the superstructure and the substructure components are selected based on certain global characteristics and dimensions of the bridge such as, height of the columns, roadway width, bent skewness and span length. The pre-designed bridges always hold the same assumptions in terms of material strength. Then, modification to footings or other components might be introduced based on site Conditions.The superstructure of these bridges consist of prestressed concrete girders that are supported by concrete bents, which usually consist of a cap beam that is 3ft x 4.5 ft (0.91 x 1.37 m) supported by a number of circular columns, typically 3 ft (0.91 m). The number of the columns depends on the bridge skewness and the roadway width. Spread footings or footings on timber piles were the common footing systems used.The MSSS prestressed concrete bridges built in Washington State in the 1960s were designed with little or no attention to seismic forces. Seismic provisions that guarantee appropriate ductility and acceptable seismic performance such as confinement, rebar splice length and girder seat-length were not considered. Only couple of girder stops where used tosupport the bridge deck against accidental lateral movement. Longitudinal restrainers were not commonly provided, as the contact length between the girders and the top of the cap beam was assumed to be sufficient to accommodate longitudinal displacement. Abutments were typically seat-type supported on strip footing or ti