土木工程 英语翻译.doc

2,4 strain capacity 552.4应变能力55 relation between the dynamic modulus of elasticity, determined by transverse vibration of cylinders, and their compressive strength 动态弹性模量之间的关系,由横向振动的汽缸、和他们的抗压强度确定it should also be noted that no information is available regarding the relationship between the static and dynamic modulus of elasticity for concrete with strength in excess of 8000 psi同样应该注意到的是没有信息可以证明关于弹性模量对混凝土强度超过8000 psi静态和动态之间的关系,2,4 strain capacity2.4应变能力The usable strain capacity of concrete can be measured either in compression or in tension ,无论在压缩或拉伸的状态下，混凝土可用应变能力可以测量in the compression mode , 在压缩模式下,it can be measured by either concentric or eccentric compression testing ,应变能力可以通过同心或偏心压缩测试测量in the tensile mode , 在拉伸模式下the behavior under multi axial stress states if outside the scope of this chapter. 在本章的范围之外的多轴向的应力状态下的行为and only the behavior under uniaxial stress condition will be discussed.只在单轴应力状态将被讨论。Stress behavior in compression压缩状态下的应力行为The stress-strain behavior is dependent on a number of parameters which include material variables such as aggregate type and testing variables such as age at testing，loading rate，strain gradient and others noted above应力-应变行为是依赖于大量的参数,其中包括材料变量如骨料类型和测试变量如年龄测试，以及其他人上面所提到的加载速率,应变梯度来测定。The effect of the aggregate type of the stress-stain curve is shown in fig2.32 which indicates that higher strength and corresponding strain are achieved for crushed aggregate from fine-grained diabase and limestone,as compared to concretes made from smooth river gravel and from crushed granite that contained inclusions of a soft mineral图32显示相对于由平滑河流砾石和碎花岗岩,含夹杂物的软矿物组成的混凝土,其总体效果类型的应力斑曲线表明碎骨料从细粒度的辉绿岩和灰岩可以达到更高的强度和相应的应变,A unmber of investigations have been undertaken to obtain the complete stress curves in compression 。上述饼状图已开展调查并获得完整的应力压缩曲线。Axial stress-strain Curves for concrete with compressive strength up to 14000 psi (98mpa) concrete as obtained by different researchers are shown in fig2.33图33显示的是由不同的研究人员测量得混凝土抗压强度高达14000 psi(98 mpa)混凝土的轴向应力-应变曲线It is generally recognized that for concrete of higher strength, 摘要显示一般情况下,对于高强度的混凝土,the shape of the ascending part of the curve become more linear and steeper ,提升部分的形状的曲线越线性越陡峭,the strain at maximum stress is slightly higher ，其最大应力应变越高,and the slope of the descending part become steeper。并且斜率的下降部分变得更陡。The existence of the post peak descending part of the stress-strain curve has been the focus of a recent paper ,邮报的存在峰值下降部分的应力-应变曲线一直是最近一篇论文中争论的焦点,it was concluded that the post peak behavior can be quantified for inclusion in finite element 研究发现该应力应变行为可以被量化后峰值列入有限元56 short term mechanical properties56短期机械性能Fig 2.33effect of the aggregate type on the ascending portion of the stress-strain curves of concrete at 28 days 图2.33骨料种类对混凝土的应力-应变曲线的提升效应为28天Analysis and that it can have considerable influence on the predicted structural behavior and strength 分析结果可以对和结构强度预测产生较大影响 To obtain the descending part of the stress-strain curve .it is necessary to avoid specimen-testing machine interaction .得到应力-应变曲线的下降是必要的,以避免试样测试机交互one approach is to use a closed-loop system with a constant rate of axial strain as a feedback signal for closed-loop operation .另一种方法是使用一个闭环系统的轴向应变恒定速率作为反馈信号闭环来操作。the difficulties of obtaining the post peak behavior experimentally and methods of overcoming these difficulties are described in a study by Ahmad and Shah . 沙艾和哈迈德的一个研究表明获得结果的困难在于怎么研究确定峰值 for very high strength concretes it may be necessary to use the lateral strains as a feedback signal rather than the axial strains . 对于非常高强度混凝土可能有必要使用横向菌株作为反馈信号而不是轴向压力。in a paper by kotsovos , 在一篇由kotsovos写的文章显示it is argued that a more realistic description of the post peak specimen behavior may be a complete and immediate loss of load-carrying capacity as soon as the peak load is exceeded . a different point of view is reflected in another recent paper which suggests that there is usable strength for concrete after peak stress . 一篇更客观的文章认为一旦超过峰值负载的实验标本立即丧失承载能力,。一个不同的角度反映在另一篇论文,可以用混凝土的强度峰值的来表示。based on the above mentioned experimental investigations ,基于上述实验调查different analytical representations for the stress-strain curve have been proposed ,不同的应力-应变曲线分析显示,they include use of a fractional equation , 它们包括使用一个分式方程or a combined power and exponential equation and serpentine curve ,the fractional equation is a comprehensive , 或结合力量和指数方程和蜿蜒的曲线,是一个综合性的分式方程yet simple way of characterizing the stress-strain response of concrete in compression . the fractional equation can be written as但简单的表明混凝土在压缩状态下的应力-应变响应的分数方程可以写成这个Where FC is the compressive stress at strain fc and e the maximum stress and corresponding strainFC表示的是压应力,应变FC和e“分别表示的是最大应力和相应的应变A and B are parameters which determine the shape of the curve A和B是确定曲线的形状参数, The values of the parameters A and B which control the shape of the ascending and the descending parts ,这些A和B参数值可以控制形状的升序和降序,respectively ,may be estimated by分别可以估计 Where FC is the compressive strength in psi and w is the unit weight in pcf ,FC是抗压强度,psi和w是pcf,的单位重量The parameters A B and E are as recommended by AHMAD and shah and were determined from the statistical analysis of the experimental results on 3*6in 参数B和E是艾哈迈德和沙阿决心从推荐的在3 * 6统计分析来研究实验结果concrete cylinders these cylinders were tested under strain controlled conditions in a closed-loop testing machine and had compressive strengths ranging from 3000 to 11000 psi 应变控制的闭环条件下测试的混凝土钢瓶压缩优势从3000到11000 psistress-strain behavior in tension应力-应变行为在张力 the direct tensile stress-strain curve is difficult to obtain ,直接测得拉伸应力-应变曲线是很难获得,due to difficulties in testing concrete in direct tension, 原因在于测试混凝土直接张力困难比较大,only limited and often conflicting data are available 只有那些有限的和经常相互矛盾的数据是可用的direct tensile tests were carried out on tapered cylindrical specimens of 4.7 in .dismeter and 11.8 in .length 直接拉伸试验,研究了直径为4.7和长度为11.8 英寸的.锥形圆柱试件 for the application of the load ,对于应用程序的负载,steel platens were glued to the top and bottom of the specimens ,粘在顶部和底部的钢压板in order to provide plane-parallel and axial connection of these platens , 是那些为了提供平行平面和轴向连接的a special gluing press was designed .这些压板是按特殊的设计比例胶合而成。 some 500 direct tensile tests , 300compressive and 300 splitting tests were performed . 一些500直接拉伸试验,300抗压和300年分裂进行了测试A typical stress-strain curve with a 95 confidence region for concrete subjected to direct tension is shown in fig 2.34,一个典型的应力-应变曲线与95年的置信区域混凝土遭受直接张力显示在图2.34中, the stress-strain curve shown in the figure is for dry specimens .应力-应变曲线的图中所示的是干标本。the results may vary slightly for specimens tested in moist conditions ,在潮湿条件下测试标本的结果可能会略有不同, a study at northwestern by Gopalaratham and Shah points out that due to the localized nature of the past-cracking deformations intension ,西北大学的一项Gopalaratham和沙的研究表明,产生局部变形的本质是由于内部的先期开裂no unique tensile stress-strain relationship exists .according to this study , 根据这项研究表明没有独特的拉伸应力-应变关系的存在。,the uniaxial tensile strength can be estimated by fc, 单轴抗拉强度可以估计fc,and the tangent modulus of elasticity is identical in tension and compression ,和切线弹性模量的张力和压缩相同的,the stress-strain relationship in tension before peak is less nonlinear than in compression 在之前施压状态下的应力应变关系比峰值非线性压缩状态下较平缓laser speckle interferometry was employed in a recent study ,在最近的一项研究采用了激光散斑干涉法to investigate the behavior of concrete subjected to uniaxial tension , 来探讨混凝土在单轴拉伸下的状态unique post-peak stress-strain and stress-deformation behavior were not observed. 并未观察到独特的高峰后应力-应变和应力变形行为。The stress-strain response of concrete was found to be sensitive to gauge-length , 混凝土的应力-应变曲线反应的是所发现的混凝土敏感表长度,strains measured within a gauge length inside the micro cracking zone were two orders of magnitude higher than values previously reported.菌株在标距长度测量的内部微裂缝区的两个数量级值高于之前的报道。In a recent study , 最近的研究显示,it was shown that while the use of strain gauges would lead to non-objective constitutive stress-strain relations , 结果表明:虽然应变仪的使用会产生非客观的本构应力-应变关系,interferometric measurements on notched specimens allow an indirect determination of the local stress-strain and stress-separation relations. 在误差允许的范围内,干涉测量在切口标本可以间接确定当地的应力-应变关系和应力分离。guo and zhang tested 29 specimens in direct tension and obtained complete stress-derived for the stress-displacement curves . 郭和张测试29标本中直接张力和获得完整的应力派生的应力位移曲线。Flexural tension弯曲张力While the information on the stress-strain behavior in tension is severely limited , 尽管这些信息在应力-应变行为在张力是极其有限的virtually no data are available regarding the strain capacity in flexural tension . 几乎没有数据可用关于应变能力在弯曲张力。this is an area for which research is sorely needed to provide a basis for design where flexural cracking is an important consideration 弯曲裂纹是一个迫切需要提供一些基础设计的研究领域,2.5 poisons ratio2.5抑制剂的比率poisons ratio under uniaxial loading conditions is defined as the ratio of lateral strain to strain in the direction of loading .抑制剂的比率在单轴加载条件下的定义是横向应变的比值来应变方向的荷载in the inelastic range, due to volume dilation resulting from internal micro cracking ,在非弹性范围,由于体积膨胀产生的内部微裂纹,the apparent poissons ratio is not constant but is an increasing function of the axial strain.明显的泊松比不是固定的,而是是一个递增函数的轴向应变。Experimental data on the values of poissons ratio for high strength concrete is very limited .泊松比的实验数据值显示高强度混凝土是非常有限的 based on the available experimental information , poissons ratio of higher strength concrete