土木工程外文翻译---建筑钢结构设计的先进分析
附件：译文建筑钢结构设计的先进分析（夏威夷大学土木工程系，美国 夏威夷 96822） 摘要：对设计者，钢结构建筑2005LRFD 规范使得在弹性和塑性范围内之行为与最高负荷极限状态下认明确的结构抵抗成为可能。
有一种提高实际次级分析的方法,来直接测定整体结构的系统响应。
本文尝试用一个简单的、简洁的、合理的综合理解来介绍一些理论和实践方法，这些方法已经在传统的、现代的工艺设计的钢结构建筑结构当中应用。
关键词：先进的分析、钢结构建筑设计、介绍1. 导论结构设计的目的是为了产生一种物质结构能够承受的环境条件。
整个设计过程中,从装载的基础上到尺寸都存在风险和费用,但基本上最终的设计是结构材料的性能和结构构件的几何缺陷的一个反应,特别是在构件生产和加工中诱发的其力学性能及残余应力,它定义了材料与构件在环境动力下的特征响应。
目前, 在工程设计实践中,有一个基本两个阶段过程的设计操作。
首先,结构的每个结构构件上作用的力必须要计算出来；其次，那些有力作用在上面的每一个结构构件的承载力必须要确定。
第一阶段包括分析作用在这些结构构件上的力和弯矩的分布；第二阶段,包括对这些构件的承载能力的认识，来抵抗作用在它们上边的力和弯矩。
越全面的理解这些知识，设计就会更加精确，结构会更加可靠。
因为构件的承载能力取决于作用在构件上的荷载类型、几何缺陷、性质、材料和残余应力的性能，对构件的承载能力的理解,大多数是根据以轴向受力构件的端柱的强度曲线,受弯构件简支梁弯曲强度曲线,构件受到轴力和弯矩相互作用下的梁柱影响曲线的形式的满载实验决定的。
这些构件的强度曲线正式的被编成构件强度曲线或者方程用于实际设计。
将框架结构构件分成三种类型,即柱、梁和梁柱。
它们各自的强度,通过理想节点或边界条件下的满载实验确定,下一阶段必须彻底简化在应力下的材料特性,以这样的方式来很容易的协助工程师分析应力分布,以估量框架结构中的结构构件。
实际上工程师主要基于材料线性弹性条件下的简单模型设计的，因为那些早期的设计基于容许应力法。
在这个过程中,材料的时间有关的影响假定是无关紧要。
这确实是在长期的行指导教师评定成绩 (五级制)：指导教师签字：为下很大的简化了材料性能。
所以这一次独立的简化,现在设计过程集中体现在降低应力水平或者结构上作用工作荷载时的水平。
这个大的安全系数是用来调整设计时考虑非弹性特性来避免失败。
在实际工程中大多数的结构分析基于线弹性分析。
一阶线性弹性分析在早期已经被结构工程师完全证明,而一个结构体系的二阶线性弹性分析已经在发展并在近些年来被逐渐的利用。
2.缩放因子下的一阶弹性结构分析在一个框架框架结构中的杆件的边界条件和一个单独杆件的边界条件是很不同的,它作为柱端强度曲线(铰接端条件)或梁强度曲线的条件(如简支梁端点条件)发展的根据。
为了估算框架构件,构件的边界条件必须调整到相等的端节点条件来进行柱的设计,比如,柱的强度曲线,可以刚好用于确定框架构件必须的尺寸(见图1)。
为实现这一等效,有效长度系数或缩放因子已经被广泛的应用在过去的与引脚端柱强度曲线相关的一个结构体系的框架构件的设计中。
有效长度的方法提供了一个良好的框架结构的设计方法。
该方法已被广泛应用于现代钢结构设计规范,包括在早年的容许应力设计和塑性设计，和在最近数年的负荷和阻力系数的设计[1]。
然而,尽管它很普及,但是有几个主要的局限性和缺点。
图1、结构体系之间相互作用的影响及其组成构件首先它不会给一个准确的对失败因子的估计,因为它不能够用正确的方法考虑结构体系、构件两者之间的强度和稳定性的相互作用的影响。
这是一个公认的事实,结构体系的实际的失效模的往往没有任何的相似，无论是根据有效长度系数K确定的结构体系的弹性屈曲模式。
第二,也许是最严重的限制,可能是当前两阶段阶段设计过程的基本原理：弹性分析是用于确定一个结构体系的每个构件上作用的荷载的分布,而构件的极限强度曲线被开用于设计是基于满布荷载或非弹性分析且每个构件被看成单独的组件[3，2]。
没有验证框架一部分的独立的构件与构件之间的兼容性。
个别构件的强度方程中规定的规格不关心系统的兼容。
因此,尚无明确的保证，所有构件将维持他们在设计荷载作用下的几何形态。
有效长度的计算方法的另一个局限,包括用电脑计算系数K有困难,没有好的电脑设计依据并且没有方法预测一个框架构件的实际强度。
为了达到这一目的,人们越来越趋向需要实际的设计/分析方法,该设计方法能够说明体系和构件之间的兼容性。
通过迅速发展的计算能力、有效性的台式电脑和有用的软件,一种替代的方法来进行直接的结构体系的设计而不使用系数K的发展变得更有吸引力,也具有现实意义。
3.缩放因子下的二阶弹结构分析采用弹性结构分析和缩放因子的钢结构设计可分为两个阶段。
在设计过程中使用缩放因子的最简单的第一阶段的发展是使用放大因子的一阶弹性分析包括通常由规范的来的二次效应[4]。
这是描述在前面的章节。
从逻辑上讲,下一阶段的进展是一个直接的二阶弹性分析而不使用有二阶影响的放大系数[4]。
这两种方法都是基于首先形成定义为第一失败的系统的塑性铰(见图2)。
如前所述,有效长度系数通常会屈服好设计对于框架结构,但它确实有以下的弊端：图2钢结构建筑结构设的计综合分析类型1)、它无法准确捕捉构件之间的相互作用和结构体系的性能和强度；2)、它不能反映出结构体系中适当的内力非弹性重分布；3)、它无法预测的结构体系的失效模式；4)、在缩放因子的计算过程中，不容易实现综合应用计算机设计与使用一致的图表；甚至最近使用AISC-LRFD程序进行抗震设计时遇到困难,因为相同强度的相关公式都必须履行检查[4]。
有些困难甚至更多的在抗震设计中自从额外的问题被提出以来,如：1)、结构是如何在地震中表现的?2)、哪一部分是最关键的地区?3)、如果结构的一部分屈服或破坏将会发生什么事情?4)、如果荷载比那些规范规定的要更大将会发生什么事情?这些问题都不能用传统的和缩放因子一起的LRFD法解决。
相反,接下来描述的下列先进的分析能提供这个信息。
4.各种先进的分析方法先进的分析方法是指任何能捕捉结构体系强度和稳定性及其独立构件，以这样一种方式分开的构件不需要检查。
因此,没有必要计算缩放因子。
通常这些分析也简称为更正式的二阶非弹性分析框架设计(见图2)。
以目前的计算能力,它是一种相当直接的过程结合,稳定性理论和塑性理论对于结构体系分析。
真正的挑战是在工程实践中为此做出这种类型的设计的新思路工作和竞争与现行方法[8]。
4.1、弹塑性铰法弹塑性铰法是最简单的非线性性能材料的近似值，它假设所有的非弹性影响都集中在了塑性铰区。
在这种理想化的条件下,它假设元件只是在形成塑性铰零长度的端点处。
在这里,在弹性分析的先前的部分,根据几何用来形成平衡方程，弹塑性铰法可以分成一阶和二阶塑性分析。
对一阶弹塑性铰分析,使用未变形的几何而非线性几何效被忽视了。
结果,预测的极限承载力和常规的刚塑性分析是一样的。
在二阶弹塑性分析中考虑了形状的改变和几何非线性形状能够在稳定型函数中使用，该函数仅能够一个构件一个构件的用在梁柱元件中来获得二阶效果。
一个关于塑性设计和二阶分析方法的全面介绍可以在由陈和索菲写的书中发现[9]。
二阶弹塑性铰分析仅是一个近似方法[10,11]。
对于破环模式是弹性失稳的细长的构件,这个方法提供了一个很好的近似方法；但是对于坚实的构件且梁柱单元承受轴向载荷和弯矩联合作用,该方法对实际强度和刚度法在塑性范围内由于屈服影响传播而产生过高评价。
该方法首先是一个的适用范围之内对框架设计良好的二阶非弹性分析的近似方法。
它在用于广泛的框架结构分析之前需要进一步改良[12]。
4.2、精确的塑性铰法精简的塑性铰方法是基于对上边描述到的弹塑性铰法一些简单的修改。
名义荷载的概念第一次被引入到传统的弹塑性铰法，它是通过运用附加虚构的等效横向负载估算残余应力的影响、构件的缺陷,但不包括传统程序中的塑性分布。
通过一定的修改,这种精炼的方法被欧洲建筑钢结构协会[13],加拿大标准和澳大利亚标准接受。
然而,柳[10]的研究表明,该方法保守估计下的强度在不同斜柱框架下超过20%的强度并且在独立梁柱承受轴向力和弯矩的情况下过度估测下的强度要达到10%。
接下来,我们将对弹塑性铰法作进一步的修改和精简,以提高其性能的同时使它在工程实践中得到应用。
这些修改分成三类:几何上的、材料上的和连接上的。
这些修改的细节可以在这两个博士论文[10,14,15]以及后续的文件中发现(例如,Refs[16，17])。
这个精简的塑性铰法就是接下来框架设计中所谓的实用先进方法。
4.2、塑性区法塑性区法被认为是“准确的”,因为它是基于一个结构体系最精炼的有限元分析。
在麦圭尔教授的领导下，康奈尔大学的研究团队在过去的二十年也已经研究和证明了这种塑性区分析方法。
这个团队的成员包括Ziemian[19],怀特,Attala[11]和Deierlein[20]以及其他人。
作为对照,弹塑性铰模型被认为是最简单的；而弹塑性区模型则最精确。
在塑性区法中,每个构件沿着长度方向被离散成许多部分,每一个部分被分成许多有限元素。
每个有限元的材料性能是指定具体的性能和残余应力。
构件的性能通过这些有限单元数值积分所获得的。
通过修改更新几何来获得二阶几何效果。
精确的解通过梁柱基准测试部分验证。
该方法适合工程实践中各种各样的简化方法。
5.实用先进的方法先进的实用方法已经成熟，在普渡大学由柳领头在过去15年前就开始了,且有据可查的校准帧,并在2005年负荷及阻力系数钢结构建筑设计规范中采用先进的分析方法。
详细的发展过程在陈和金[22]1997年的“LRFD钢铁设计采用先进的分析”一书中有综合描述。
由此，根据我们工程实践中学到的经验,实用先进的分析方法必须降低到一个序列的等效线性弹性分析。
容许应力设计和在早年为了获得接受应用到工程实践中的弹塑性铰设计是如此的普遍。
接下来,我将简要总结它的发展，根据理想化单一化的几何形状、材料和连接达到这个目标,同时满足当前的LRFD要求。
在这个发展过程中,它最初开始使用熟悉但简化稳定的功能来捕捉二阶效应,继续展示由于残余应力如何传播的可塑性。
这可以解释为减少材料的弹性模量的影响,最后指出的几何缺陷,可以进行进一步的减化弹性模量结构体系的设计过程和弹性分析。
5.1、二阶效应为了捕捉二次效应，陈和吕[23]指出要采取简化稳定作用。
5.2、截面塑性强度这个LRFD截面塑性强度曲线被采用，因为强轴和弱轴都受弯在LRFD规范中，减少的相同的因数取为0.85对强轴而弯曲强度取为90%。
5.3，残余应力CRC正切弹性模数是由于残余应力在轴向荷载下沿构件长度方向逐渐屈服的原因。
在这种方法中,弹性模量E代替惯性矩I被减少是弹性的部分减少的原因。
土木工程专业外文文献及翻译
土木工程专业外文文献及翻译外文文献及翻译学号：学校代码：（二〇一二年六月题目： About Buiding on the Structure Design 学生姓名：学院：土木工程学院系别：建筑工程系专业：土木工程(建筑工程方向) 班级：土木08-4班指导教师：英文原文：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread e某istencebut again difficult in solve of engineering actual problem, this te某t carried on a study analysis to a little bit familiarcrack problem in the concrete engineering, and aim at concretethe circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mi某ture but formation of the inaddition material of quality brittleness not andall the concrete construction transform with oneself,control etc. a series problem, harden model of in the concrete e某istence numerous tiny hole, spirit cave and tiny crack, is e某actly because these beginning start blemish of e某istencejust make the concrete present one some not and all the characteristic of tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of e某pand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of e某istence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of e某ternal appearance, service life, severity will threat arrive people's life and property lot of all of crash of engineerings is because of the unsteady development of the crack with the result age science research with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly ofthe scope just need to adopt valid of measure will it endanger degree control at certain of scope reinforced concrete norm is also e某plicit provision:Some structure at place ofdissimilarity under the condition allow e某istence certain the crack of at under construction should as far as possible adopt a valid measure control crack creation, make the structure don'tappear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention Suo crack and preventionSu constringency crack and preventionto sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation kind crack manyis deep enter or pierce through se某 crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 ° Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion width under the influence of temperature variety foundation after transform stability sink to sink crack also basic tend in stability.crack and prevention。
土木工程毕业设计外文翻译原文+翻译
The bridge crack produced the reason to simply analyseIn recent years, the traffic capital construction of our province gets swift and violent development, all parts have built a large number of concrete bridges. In the course of building and using in the bridge, relevant to influence project quality lead of common occurrence report that bridge collapse even because the crack appears The concrete can be said to " often have illness coming on " while fracturing and " frequently-occurring disease ", often perplex bridge engineers and technicians. In fact , if take certain design and construction measure, a lot of cracks can be overcome and controlled. For strengthen understanding of concrete bridge crack further, is it prevent project from endanger larger crack to try one's best, this text make an more overall analysis , summary to concrete kind and reason of production , bridge of crack as much as possible, in order to design , construct and find out the feasible method which control the crack , get the result of taking precautions against Yu WeiRan.Concrete bridge crack kind, origin cause of formation In fact, the origin cause of formation of the concrete structure crack is complicated and various, even many kinds of factors influence each other , but every crack has its one or several kinds of main reasons produced . The kind of the concrete bridge crack, on its reason to produce, can roughly divide several kinds as follows :(1) load the crack caused Concrete in routine quiet .Is it load to move and crack that produce claim to load the crack under the times of stress bridge, summing up has direct stress cracks , two kinds stress crack onces mainly. Direct stress crack refer to outside load direct crack that stress produce that cause. The reason why the crack produces is as follows, 1, Design the stage of calculating , does not calculate or leaks and calculates partly while calculating in structure; Calculate the model is unreasonable; The structure is supposed and accorded with by strength actually by strength ; Load and calculate or leak and calculate few; Internal force and matching the mistake in computation of muscle; Safety coefficient of structure is not enough. Do not consider the possibility that construct at the time of the structural design; It is insufficientto design the section; It is simply little and assigning the mistake for reinforcing bar to set up; Structure rigidity is insufficient; Construct and deal with improperly; The design drawing can not be explained clearly etc.. 2, Construction stage, does not pile up and construct the machines , material limiting ; Is it prefabricate structure structure receive strength characteristic , stand up , is it hang , transport , install to get up at will to understand; Construct not according to the design drawing, alter the construction order of the structure without authorization , change the structure and receive the strength mode; Do not do the tired intensity checking computations under machine vibration and wait to the structure . 3, Using stage, the heavy-duty vehicle which goes beyond the design load passes the bridge; Receive the contact , striking of the vehicle , shipping; Strong wind , heavy snow , earthquake happen , explode etc.. Stress crack once means the stress of secondary caused by loading outside produces the crack. The reason why the crack produces is as follows, 1, In design outside load function , because actual working state and routine , structure of thing calculate have discrepancy or is it consider to calculate, thus cause stress once to cause the structure to fracture in some position. Two is it join bridge arch foot is it is it assign " X " shape reinforcing bar , cut down this place way , section of size design and cut with scissors at the same time to adopt often to design to cut with scissors, theory calculate place this can store curved square in , but reality should is it can resist curved still to cut with scissors, so that present the crack and cause the reinforcing bar corrosion. 2, Bridge structure is it dig trough , turn on hole , set up ox leg ,etc. to need often, difficult to use a accurate one diagrammatic to is it is it calculate to imitate to go on in calculating in routine, set up and receive the strength reinforcing bar in general foundation experience. Studies have shown , after being dug the hole by the strength component , it will produce the diffraction phenomenon that strength flows, intensive near the hole in a utensil, produced the enormous stress to concentrate. In long to step prestressing force of the continuous roof beam , often block the steel bunch according to the needs of section internal force in stepping, set up the anchor head, but can often see the crack in the anchor firm section adjacent place. So if deal with improper, in corner or component form sudden change office , block place to be easy to appear crack strengthreinforcing bar of structure the. In the actual project, stress crack once produced the most common reason which loads the crack. Stress crack once belong to one more piece of nature of drawing , splitting off , shearing. Stress crack once is loaded and caused, only seldom calculate according to the routine too, but with modern to calculate constant perfection of means, times of stress crack to can accomplish reasonable checking computations too. For example to such stresses 2 times of producing as prestressing force , creeping ,etc., department's finite element procedure calculates levels pole correctly now, but more difficult 40 years ago. In the design, should pay attention to avoiding structure sudden change (or section sudden change), when it is unable to avoid , should do part deal with , corner for instance, make round horn , sudden change office make into the gradation zone transition, is it is it mix muscle to construct to strengthen at the same time, corner mix again oblique to reinforcing bar , as to large hole in a utensil can set up protecting in the perimeter at the terms of having angle steel. Load the crack characteristic in accordance with loading differently and presenting different characteristics differently. The crack appear person who draw more, the cutting area or the serious position of vibration. Must point out , is it get up cover or have along keep into short crack of direction to appear person who press, often the structure reaches the sign of bearing the weight of strength limit, it is an omen that the structure is destroyed, its reason is often that sectional size is partial and small. Receive the strength way differently according to the structure, the crack characteristic produced is as follows: 1, The centre is drawn. The crack runs through the component cross section , the interval is equal on the whole , and is perpendicular to receiving the strength direction. While adopting the whorl reinforcing bar , lie in the second-class crack near the reinforcing bar between the cracks. 2, The centre is pressed. It is parallel on the short and dense parallel crack which receive the strength direction to appear along the component. 3, Receive curved. Most near the large section from border is it appear and draw into direction vertical crack to begin person who draw curved square, and develop toward neutralization axle gradually. While adopting the whorl reinforcing bar , can see shorter second-class crack among the cracks. When the structure matches muscles less, there are few but wide cracks, fragility destruction may take place in thestructure 4, Pressed big and partial. Heavy to press and mix person who draw muscle a less one light to pigeonhole into the component while being partial while being partial, similar to receiving the curved component. 5, Pressed small and partial. Small to press and mix person who draw muscle a more one heavy to pigeonhole into the component while being partial while being partial, similar to the centre and pressed the component. 6, Cut. Press obliquly when the hoop muscle is too dense and destroy, the oblique crack which is greater than 45?? direction appears along the belly of roof beam end; Is it is it is it destroy to press to cut to happen when the hoop muscle is proper, underpart is it invite 45?? direction parallel oblique crack each other to appear along roof beam end. 7, Sprained. Component one side belly appear many direction oblique crack, 45?? of treaty, first, and to launch with spiral direction being adjoint. 8, Washed and cut. 4 side is it invite 45?? direction inclined plane draw and split to take place along column cap board, form the tangent plane of washing. 9, Some and is pressed. Some to appear person who press direction roughly parallel large short cracks with pressure.(2) crack caused in temperature changeThe concrete has nature of expanding with heat and contract with cold, look on as the external environment condition or the structure temperature changes, concrete take place out of shape, if out of shape to restrain from, produce the stress in the structure, produce the temperature crack promptly when exceeding concrete tensile strength in stress. In some being heavy to step foot-path among the bridge , temperature stress can is it go beyond living year stress even to reach. The temperature crack distinguishes the main characteristic of other cracks will be varied with temperature and expanded or closed up. The main factor is as follows, to cause temperature and change 1, Annual difference in temperature. Temperature is changing constantly in four seasons in one year, but change relatively slowly, the impact on structure of the bridge is mainly the vertical displacement which causes the bridge, can prop up seat move or set up flexible mound ,etc. not to construct measure coordinate , through bridge floor expansion joint generally, can cause temperature crack only when the displacement of the structure is limited, for example arched bridge , just bridge etc. The annual difference in temperature of our country generally changes therange with the conduct of the average temperature in the moon of January and July. Considering the creep characteristic of the concrete, the elastic mould amount of concrete should be considered rolling over and reducing when the internal force of the annual difference in temperature is calculated. 2, Rizhao. After being tanned by the sun by the sun to the side of bridge panel , the girder or the pier, temperature is obviously higher than other position, the temperature gradient is presented and distributed by the line shape . Because of restrain oneself function, cause part draw stress to be relatively heavy, the crack appears. Rizhao and following to is it cause structure common reason most , temperature of crack to lower the temperature suddenly 3, Lower the temperature suddenly. Fall heavy rain , cold air attack , sunset ,etc. can cause structure surface temperature suddenly dropped suddenly, but because inside temperature change relatively slow producing temperature gradient. Rizhao and lower the temperature internal force can adopt design specification or consult real bridge materials go on when calculating suddenly, concrete elastic mould amount does not consider converting into and reducing 4, Heat of hydration. Appear in the course of constructing, the large volume concrete (thickness exceeds 2. 0), after building because cement water send out heat, cause inside very much high temperature, the internal and external difference in temperature is too large, cause the surface to appear in the crack. Should according to actual conditions in constructing, is it choose heat of hydration low cement variety to try one's best, limit cement unit's consumption, reduce the aggregate and enter the temperature of the mould , reduce the internal and external difference in temperature, and lower the temperature slowly , can adopt the circulation cooling system to carry on the inside to dispel the heat in case of necessity, or adopt the thin layer and build it in succession in order to accelerate dispelling the heat. 5, The construction measure is improper at the time of steam maintenance or the winter construction , the concrete is sudden and cold and sudden and hot, internal and external temperature is uneven , apt to appear in the crack. 6, Prefabricate T roof beam horizontal baffle when the installation , prop up seat bury stencil plate with transfer flat stencil plate when welding in advance, if weld measure to be improper, iron pieces of nearby concrete easy to is it fracture to burn. Adopt electric heat piece draw law piece draw prestressing force at the component ,prestressing force steel temperature can rise to 350 degrees Centigrade , the concrete component is apt to fracture. Experimental study indicates , are caused the intensity of concrete that the high temperature burns to obviously reduce with rising of temperature by such reasons as the fire ,etc., glueing forming the decline thereupon of strength of reinforcing bar and concrete, tensile strength drop by 50% after concrete temperature reaches 300 degrees Centigrade, compression strength drops by 60%, glueing the strength of forming to drop by 80% of only round reinforcing bar and concrete; Because heat, concrete body dissociate ink evaporate and can produce and shrink sharply in a large amount(3) shrink the crack causedIn the actual project, it is the most common because concrete shrinks the crack caused. Shrink kind in concrete, plasticity shrink is it it shrinks (is it contract to do ) to be the main reason that the volume of concrete out of shape happens to shrink, shrink spontaneously in addition and the char shrink. Plasticity shrink. About 4 hours after it is built that in the course of constructing , concrete happens, the cement water response is fierce at this moment, the strand takes shape gradually, secrete water and moisture to evaporate sharply, the concrete desiccates and shrinks, it is at the same time conduct oneself with dignity not sinking because aggregate,so when harden concrete yet,it call plasticity shrink. The plasticity shrink producing amount grade is very big, can be up to about 1%. If stopped by the reinforcing bar while the aggregate sinks, form the crack along the reinforcing bar direction. If web , roof beam of T and roof beam of case and carry baseplate hand over office in component vertical to become sectional place, because sink too really to superficial obeying the web direction crack will happen evenly before hardenning. For reducing concrete plasticity shrink,it should control by water dust when being construct than,last long-time mixing, unloading should not too quick, is it is it take closely knit to smash to shake, vertical to become sectional place should divide layer build. Shrink and shrink (do and contract). After the concrete is formed hard , as the top layer moisture is evaporated progressively , the humidity is reduced progressively , the volume of concrete is reduced, is called and shrunk to shrink (do and contract). Because concrete top layermoisture loss soon, it is slow for inside to lose, produce surface shrink heavy , inside shrink a light one even to shrink, it is out of shape to restrain from by the inside concrete for surface to shrink, cause the surface concrete to bear pulling force, when the surface concrete bears pulling force to exceed its tensile strength, produce and shrink the crack. The concrete hardens after-contraction to just shrink and shrink mainly .Such as mix muscle rate heavy component (exceed 3% ), between reinforcing bar and more obvious restraints relatively that concrete shrink, the concrete surface is apt to appear in the full of cracks crackle. Shrink spontaneously. Spontaneous to it shrinks to be concrete in the course of hardenning , cement and water take place ink react, the shrink with have nothing to do by external humidity, and can positive (whether shrink, such as ordinary portland cement concrete), can negative too (whether expand, such as concrete, concrete of slag cement and cement of fly ash). The char shrinks. Between carbon dioxide and hyrate of cement of atmosphere take place out of shape shrink that chemical reaction cause. The char shrinks and could happen only about 50% of humidity, and accelerate with increase of the density of the carbon dioxide. The char shrinks and seldom calculates . The characteristic that the concrete shrinks the crack is that the majority belongs to the surface crack, the crack is relatively detailed in width , and criss-cross, become the full of cracks form , the form does not have any law . Studies have shown , influence concrete shrink main factor of crack as follows, 1, Variety of cement , grade and consumption. Slag cement , quick-hardening cement , low-heat cement concrete contractivity are relatively high, ordinary cement , volcanic ash cement , alumina cement concrete contractivity are relatively low. Cement grade low in addition, unit volume consumption heavy rubing detailed degree heavy, then the concrete shrinks the more greatly, and shrink time is the longer. For example, in order to improve the intensity of the concrete , often adopt and increase the cement consumption method by force while constructing, the result shrinks the stress to obviously strengthen . 2, Variety of aggregate. Such absorbing water rates as the quartz , limestone , cloud rock , granite , feldspar ,etc. are smaller, contractivity is relatively low in the aggregate; And such absorbing water rates as the sandstone , slate , angle amphibolite ,etc. are greater, contractivity is relatively high. Aggregate grains of foot-path heavy to shrink light inaddition, water content big to shrink the larger. 3, Water gray than. The heavier water consumption is, the higher water and dust are, the concrete shrinks the more greatly. 4, Mix the pharmaceutical outside. It is the better to mix pharmaceutical water-retaining property outside, then the concrete shrinks the smaller. 5, Maintain the method . Water that good maintenance can accelerate the concrete reacts, obtain the intensity of higher concrete. Keep humidity high , low maintaining time to be the longer temperature when maintaining, then the concrete shrinks the smaller. Steam maintain way than maintain way concrete is it take light to shrink naturall. 6, External environment. The humidity is little, the air drying , temperature are high, the wind speed is large in the atmosphere, then the concrete moisture is evaporated fast, the concrete shrinks the faster. 7, Shake and smash the way and time. Machinery shake way of smashing than make firm by ramming or tamping way concrete contractivity take little by hand. Shaking should determine according to mechanical performance to smash time , are generally suitable for 55s / time. It is too short, shake and can not smash closely knit , it is insufficient or not even in intensity to form the concrete; It is too long, cause and divide storey, thick aggregate sinks to the ground floor, the upper strata that the detailed aggregate stays, the intensity is not even , the upper strata incident shrink the crack. And shrink the crack caused to temperature, worthy of constructing the reinforcing bar againing can obviously improve the resisting the splitting of concrete , structure of especially thin wall (thick 200cm of wall ). Mix muscle should is it adopt light diameter reinforcing bar (8 |? construct 14 |? ) to have priority , little interval assign (whether @ 10 construct @ 15cm ) on constructing, the whole section is it mix muscle to be rate unsuitable to be lower than 0 to construct. 3%, can generally adopt 0 . 3%~0. 5%.(4), crack that causes out of shape of plinth of the groundBecause foundation vertical to even to subside or horizontal direction displacement, make the structure produce the additional stress, go beyond resisting the ability of drawing of concrete structure, cause the structure to fracture. The even main reason that subside of the foundation is as follows, 1, Reconnoitres the precision and is not enough for , test the materials inaccuratly in geology. Designing, constructing without fully grasping the geological situation, this is the main reason that cause the ground not to subside evenly .Such as hills area or bridge, district of mountain ridge,, hole interval to be too far when reconnoitring, and ground rise and fall big the rock, reconnoitring the report can't fully reflect the real geological situation . 2, The geological difference of the ground is too large. Building it in the bridge of the valley of the ditch of mountain area, geology of the stream place and place on the hillside change larger, even there are weak grounds in the stream, because the soil of the ground does not causes and does not subside evenly with the compressing. 3, The structure loads the difference too big. Under the unanimous terms, when every foundation too heavy to load difference in geological situation, may cause evenly to subside, for example high to fill out soil case shape in the middle part of the culvert than to is it take heavy to load both sides, to subside soon heavy than both sides middle part, case is it might fracture to contain 4, The difference of basic type of structure is great. Unite it in the bridge the samly , mix and use and does not expand the foundation and a foundation with the foundation, or adopt a foundation when a foot-path or a long difference is great at the same time , or adopt the foundation of expanding when basis elevation is widely different at the same time , may cause the ground not to subside evenly too 5, Foundation built by stages. In the newly-built bridge near the foundation of original bridge, if the half a bridge about expressway built by stages, the newly-built bridge loads or the foundation causes the soil of the ground to consolidate again while dealing with, may cause and subside the foundation of original bridge greatly 6, The ground is frozen bloatedly. The ground soil of higher moisture content on terms that lower than zero degree expands because of being icy; Once temperature goes up , the frozen soil is melted, the setting of ground. So the ground is icy or melts causes and does not subside evenly . 7, Bridge foundation put on body, cave with stalactites and stalagmites, activity fault,etc. of coming down at the bad geology, may cause and does not subside evenly . 8, After the bridge is built up , the condition change of original ground . After most natural grounds and artificial grounds are soaked with water, especially usually fill out such soil of special ground as the soil , loess , expanding in the land ,etc., soil body intensity meet water drop, compress out of shape to strengthen. In the soft soil ground , season causes the water table to drop to draw water or arid artificially, the ground soil layer consolidates and sinks again,reduce the buoyancy on the foundation at the same time , shouldering the obstruction of rubing to increase, the foundation is carried on one's shoulder or back and strengthened .Some bridge foundation is it put too shallow to bury, erode , is it dig to wash flood, the foundation might be moved. Ground load change of terms, bridge nearby is it is it abolish square , grit ,etc. in a large amount to put to pile with cave in , landslide ,etc. reason for instance, it is out of shape that the bridge location range soil layer may be compressed again. So, the condition of original ground change while using may cause and does not subside evenly Produce the structure thing of horizontal thrust to arched bridge ,etc., it is the main reason that horizontal displacement crack emerges to destroy the original geological condition when to that it is unreasonable to grasp incompletely , design and construct in the geological situation.桥梁裂缝产生原因浅析近年来，我省交通基础建设得到迅猛发展，各地建立了大量的混凝土桥梁。
土木工程专业外文翻译--建筑物的结构
外文原文Text Structure of BuildingsReading Material A Structural Planning and design Reading Material B Types of Loads and Types of StressContentsUNIT ONEText Introduction to Mechanics of MaterialsReading Material A Shear CenterB Allowable Stress Design and Strength DesignUNIT TWOText The Tensile TestReading Material A Comparative Study of the Mechanical Properties of Ductile and Brittle MaterialsB Strength TheoriesUNIT THREEText Application of Mechanics of Materials and Its Study MethodReading Material A StressB Method of SectionsUNIT FOURText Description of the Force and Displacement MethodReading Material A Types of BeamsB Methods of Joints and Sections for Analyzing a TrussUNIT FIVEText Structure of BuildingsReading Material A Structural Planning and DesignB Types of Loads and Types of StressUNIT SIXText Purpose of Structural Analysis, Modeling of Structures and Relation of Analysis and DesignReading Material A Matrix Analysis of Structures by the Stiffness MethodB Equilibrium of Single MembersUNIT SEVENText Properties of Concrete and Reinforced ConcreteReading Material A Property of Structural SteelB Nature of Wood and MasonryUNIT EIGHTText Building Code (Ⅰ)Reading Material A Building Code (Ⅱ)B Building Code (Ⅲ)UNIT NINEText Early History of Cement and ConcreteReading Material A The Hydration ReactionB Distress and Failure of ConcreteUNIT TENText Advantages and Disadvantages of Concrete and Its Water-Cement Ratio Reading Material A Slump Test and Concrete ProportioningB Curing ConcreteUNIT ELEVENText MortarReading Material A Water RetentivelyB Cement Mortar and Lime MortarUNIT TWELVEText General Planning ConsiderationsReading Material A HousingB HouseUNIT THIRTEENText Factory DesignReading Material A Modern Building ConstructionB BuildingUNIT FOURTEENText Fundamental Objective of Structural Dynamics AnalysisReading Material A Organization of the TextB Methods of Discret iza tionUNIT FIFTEENText Contents of Theory of ElasticityReading Material A Basic Assumptions in Classical ElasticityB Members in a State of Two-Dimensional StressUNIT SIXTEENText Historical Development of Finite Element MethodReading Material A General Description of the Finite Element MethodB Introduction of Displacement ApproachAppendix ⅠVocabularyAppendix ⅡTranslation for ReferenceAppendix ⅢKey to Exercises目录一、Foreign original UNIT FIVE1.Text Structure of Buildings··········································1-32.Reading Material A Structural Planning anddesign·················································································4-5 3.Reading Material B Types of Loads and Types ofStress·················································································6-8⑴Types of Loads································································6-7⑵Types of stress····························································7-8二、外文译文第五单元1.课文建筑物的结构···························································9-102.阅读材料 A 结构的规划和设计 (11)3.阅读材料 B 荷载类型及应力类型··································12-13⑴负载类型 (12)⑵应力类型 (13)UNIT FIVEText Structure of Buildings[1] Considering only the engineering essentials, the structure of a building can be defined as the assemblage of those parts which exist for the purpose of maintaining shape and stability. Its primary purpose is to resist any loads applied to the building and to transmit those to the ground.[2] In terms of architecture, the structure of a building is and does much more than that. It is an inseparable part of the building form and to varying degrees is a generator of that form. Used skillfully, the building structure can establish or reinforce orders and rhythms among the architectural volumes and planes. It can be visually dominant or recessive. It can develop harmonies or conflicts. It can be both confining and emancipating. And, unfortunately in some cases, it cannot be ignored. It is physical.[3] The structure must also be engineered to maintain the architectural form. The principles and tools of physics and mathematics provide the basis for differentiating between rational and irrational forms in terms of construction. Artists can sometimes generate shapes that obviate any consideration of science, but architects cannot.[4] There are at least three items that must be present in the structure of a building:stabilitystrength and stiffnesseconomy[5] Taking the first of the three requirements, it is obvious that stability is needed to maintain shape. An unstable building structure implies unbalanced forces or a lack of equilibrium and a consequent acceleration of the structure or its pieces.[6] The requirement of strength means that the materials selected to resist the stresses generated by the loads and shapes of the structure (s) must be adequate. Indeed, a "factor of safety" is usually providedso that under the anticipated loads, a given material is not stressed to a level even close to its rupture point. The material property called stiffness is considered with the requirement of strength. Stiffness is different from strength in that it directly involves how much a structure strains or deflects under load. A material that is very strong but lacking in stiffness will deform too much to be of value in resisting the forces applied.[7] Economy of a building structure refers to more than just the cost of the materials used. Construction economy is a complicated subject involving raw materials, fabrication, erection, and maintenance. Design and construction labor costs and the costs of energy consumption must be considered. Speed of construction and the cost of money (interest) are also factors. In most design situations, more than one structural material requires consideration. Competitive alternatives almost always exist, and the choice is seldom obvious.[8] Apart from these three primary requirements, several other factors are worthy of emphasis. First, the structure or structural system must relate to the building's function. It should not be in conflict in terms of form. For example, a linear function demands a linear structure, and therefore it would be improper to roof a bowling alley with a dome. Similarly, a theater must have large, unobstructed spans but a fine restaurant probably should not. Stated simply, the structure must be appropriate to the function it is to shelter.[9] Second, the structure must be fire-resistant. It is obvious that the structural system must be able to maintain its integrity at least until the occupants are safely out. Building codes specify the number of hours for which certain parts of a building must resist the heat without collapse. The structural materials used for those elements must be inherently fire-resistant or be adequately protected by fireproofing materials. The degree of fire resistance to be provided will depend upon a number of items, including the use and occupancy load of the space, its dimensions, and the location of the building.[10] Third, the structure should integrate well with the building's circulation systems. It should not be in conflict with the piping systemsfor water and waste, the ducting systems for air, or (most important) the movement of people. It is obvious that the various building systems must be coordinated as the design progresses. One can design in a sequential step-by-step manner within any one system, but the design of all of them should move in a parallel manner toward completion. Spatially, all the various parts of a building are interdependent.[11] Fourth, the structure must be psychologically safe as well as physically safe. A high-rise frame that sways considerably in the wind might not actually be dangerous but may make the building uninhabitable just the same. Lightweight floor systems that are too “bouncy" can make the users very uncomfortable. Large glass windows, uninterrupted by dividing mullions, can be quite safe but will appear very insecure to the occupant standing next to one 40 floors above the street.[12] Sometimes the architect must make deliberate attempts to increase the apparent strength or solidness of the structure. This apparent safety may be more important than honestly expressing the building's structure, because the untrained viewer cannot distinguish between real and perceived safety.Reading Material AStructural Planning and designThe building designer needs to understand the behavior of physical structures under load. An ability to intuit or "feel" structural behavior is possessed by those having much experience involving structural analysis, both qualitative and quantitative. The consequent knowledge of how forces, stresses, and deformations build up in different materials and shapes is vital to the development of this ”sense”。
土木工程 外文翻译 外文文献 英文文献
一、外文原文Talling building and Steel construction Although there have been many advancements in building construction technology in general. Spectacular archievements have been made in the design and construction of ultrahigh-rise buildings.The early development of high-rise buildings began with structural steel framing.Reinforced concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes.The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structual systems.Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit.Excessive lateral sway may cause serious recurring damage to partitions,ceilings.and other architectural details. In addition,excessive sway may cause discomfort to the occupants of the building because their perception of such motion.Structural systems of reinforced concrete,as well as steel,take full advantage of inherent potential stiffness of the total building and therefore require additional stiffening to limit the sway.In a steel structure,for example,the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building.Curve A in Fig .1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B represents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.Structural engineers have developed structural systems with a view to eliminating this premium.Systems in steel. Tall buildings in steel developed as a result ofseveral types of structural innovations. The innovations have been applied to the construction of both office and apartment buildings.Frame with rigid belt trusses. In order to tie the exterior columns of a frame structure to the interior vertical trusses,a system of rigid belt trusses at mid-height and at the top of the building may be used. A good example of this system is the First Wisconsin Bank Building(1974) in Milwaukee.Framed tube. The maximum efficiency of the total structure of a tall building, for both strength and stiffness,to resist wind load can be achieved only if all column element can be connected to each other in such a way that the entire building acts as a hollow tube or rigid box in projecting out of the ground. This particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this system is in the twin structural steel towers of the 110-story World Trade Center building in New York Column-diagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with diagonal members interesting at the centre line of the columns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Centre in Chicago, using as much steel as is normally needed for a traditional 40-story building.Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the column-diagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The 110-story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept. The Sears tower, at a height of 1450 ft(442m), is the world’s tallest building.Stressed-skin tube system. The tube structural system was developed for improving the resistance to lateral forces (wind and earthquake) and thecontrol of drift (lateral building movement ) in high-rise building. The stressed-skin tube takes the tube system a step further. The development of the stressed-skin tube utilizes the façade of the building as a structural element which acts with the framed tube, thus providing an efficient way of resisting lateral loads in high-rise buildings, and resulting in cost-effective column-free interior space with a high ratio of net to gross floor area.Because of the contribution of the stressed-skin façade, the framed members of the tube require less mass, and are thus lighter and less expensive. All the typical columns and spandrel beams are standard rolled shapes,minimizing the use and cost of special built-up members. The depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which would encroach on valuable space, is minimized. The structural system has been used on the 54-story One Mellon Bank Center in Pittburgh.Systems in concrete. While tall buildings constructed of steel had an early start, development of tall buildings of reinforced concrete progressed at a fast enough rate to provide a competitive chanllenge to structural steel systems for both office and apartment buildings.Framed tube. As discussed above, the first framed tube concept for tall buildings was used for the 43-story DeWitt Chestnut Apartment Building. In this building ,exterior columns were spaced at 5.5ft (1.68m) centers, and interior columns were used as needed to support the 8-in . -thick (20-m) flat-plate concrete slabs.Tube in tube. Another system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system known as the tube-in-tube system , made it possible to design the world’s present tallest (714ft or 218m)lightweight concrete bu ilding( the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.Systems combining both concrete and steel have also been developed, an examle of which is the composite system developed by skidmore, Owings &Merril in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The 52-story One Shell Square Building in New Orleans is based on this system.Steel construction refers to a broad range of building construction in which steel plays the leading role. Most steel construction consists of large-scale buildings or engineering works, with the steel generally in the form of beams, girders, bars, plates, and other members shaped through the hot-rolled process. Despite the increased use of other materials, steel construction remained a major outlet for the steel industries of the U.S, U.K, U.S.S.R, Japan, West German, France, and other steel producers in the 1970s.二、原文翻译高层结构与钢结构近年来，尽管一般的建筑结构设计取得了很大的进步，但是取得显著成绩的还要属超高层建筑结构设计。
土木工程专业钢筋混凝土结构设计毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土结构设计文献、资料英文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文参考资料及译文译文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and thestress of steel bars will increase . When the steel approaches the yielding stress ƒy , thedeflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large cross sections .As concrete has high modulus of elasticity, reinforced concrete structures are usuallystiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(b)Reinfoced concrete beam(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures are cheaper.(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforcedconcrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressed concrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid。
土木工程专业毕业设计外文文献翻译2篇
土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。
钢结构设计外文翻译参考文献
钢结构设计外文翻译参考文献In the United States。
XXX (ASD)。
Plastic Design (PD)。
and Load and Resistance Factor Design (LRFD)。
In ASD。
stress ns are based on first-order elastic analysis。
XXX。
In PD。
first-order plastic hinge analysis is used in structural analysis。
XXX progressive collapse effects are not included in PD。
they are XXX LRFD。
first-order XXX。
and the XXX。
All three design methods require independent checks。
including K factor ns。
In this paper。
XXX structural system and its components are related。
but the current LRFD n of the American Institute of Steel n (AISC) separates them。
In practical ns。
the XXX in the effective length factor。
This is described in the excerpt from the Technical Memorandum on Social Science Research。
Volume 5.Although the maximum internal forces of the structure and the maximum internal forces of the components are interdependent (but not necessarily coexisting)。
土木工程外文翻译框架EE---结构特性分析
本外文文献来自《Simplified Design of Steel Structures》（《钢结构简化设计丛书第七版》）,作者James Ambrose（詹姆斯·安布罗斯）。
INVESTIGATION OF STRUCTURAL BEHA VIORInvestigating how structures behave is an important part of structural design: it provides a basis for ensuring the adequacy and safety of a design, In this section I discuss structural investigation in general. As I do throughout this book. I focus on material relevant to structural design tasks.Purpose of InvestigationMost structures exist because they are needed. Any evaluation of a structure thus must begin with an analysis of how effectively the structure meets the usage requirements.Designers must consider the following three factors:●Functionality. or the general physical relationships of the structure's form.detail. durability. fire resistance. deformation resistance. and so on.●Feasibility. including cost. availability of materials and products. andpracticality of construction.●Safety. or capacity 10 resist anticipated loads.MeansAn investigation of a fully defined structure involves the following:1.Determine the structure's physical being-materials, form, scale. orientation.location. support conditions, and internal character and detail.2.Determine the demands placed on the structure-that is. loads.3.Determine the structure's deformation limits.4.Determine the structure's load response-how it handles internal forces andstresses and significant deformations.5.Evaluate whether the structure can safely handle the required structural tasks.Investigation may take several forms. You can●Visualize graphically the structure's deformation under load.●Manipulate mathematical models.●Test the structure or a scaled model, measuring its responses to loads.When precise quantitative evaluations are required. use mathematical models based on reliable theories or directly measure physical responses. Ordinarily. mathematical modeling precedes any actual construction-even of a test model. Limit direct mea-surementto experimental studies or to verifying untested theories or design methods. Visual AidsIn this book, I emphasize graphical visualization; sketches arc invaluable learning and problem-solving aids. Three types of graphics are most useful: the free-body diagram. the exaggerated profile of a load-deformed structure. and the scaled pial.A free-body diagram combines a picture of an isolated physical clemen I with representations of all external forces. The isolated clement may be a whole structure or some part of it.For example. Figure 4.1a shows anentire structure-a beamand-eolumn rigidbent-and the external forces (representedby arrows). which include gravity. wind.and the reactive resistance of thesupports (called the reactions). Note:Such a force system holds the structurein static equilibrium.Figure 4.lb is a free-body diagramof a single beam from the bent.Operating on the beam are two forces: itsown weight and the interaction betweenthe beam ends and the columns 10 whichthe beam is all ached. These interactionsare not visible in the Ireebody diagram ofthe whole bent. so one purpose of thediagram for the beam is to illustrate theseinteractions. For example. note that the columns transmit to theendsofthe beams horizontal and vertical forces as well asrotational bending actions.Figure 4.lc shows an isolated portion ofthe beam length. illustrating the beam's internal force actions. Operating on this free body arc its own weight and the actions of the beam segments on the opposite sides of the slicing planes. since it is these actions that hold the removed portion in place in the whole beam.Figure 4.ld. a tiny segment. or particle. of the beam material is isolated, illustrating the interactions between this particle and those adjacent to it. This device helps designers visualize stress: in this case. due to its location in the beam. the particle is subjected to a combination of shear and linear compression stresses.An exaggerated profile of a load-deformed structure helps establish the qualitative nature of the relationships between force actions and shape changes. Indeed. you can infer the form deformation from the type of force or stress. and vice versa.IGURE 4.1Free-body diagrams.For example. Figure shows {he exaggerated deformation of the bent in Figure 4.1 under wind loading. Note how you can determine the nature of bending action in each member of the frame from this figure. Figure 4.2b shows the nature of deformation of individual particles under various types of stress.FIGURE 4.2 Structural deformationThe scaled plot is a graph of some mathematical relationship or real data. For example, the graph in Figure 4.3 represents the form of a damped ibration of an elastic spring. It consists of the plot of the displacements against elapsed time t. and represents the graph of the expression.FIGURE 4.3 Graphical plot of a damped cyclic motion.Although the equation is technically sufficient to describe the phenomenon, the graphillustrates many aspects of the relationship. such as the rate of decay of the displacement. the interval of the vibration. the specific position at some specific elapsed time. and so on..4.2 METHODS OF INVESTIGATION AND DESIGNTraditional structural design centered on the working stress method. a method now referred to as stress design or allowable stress design (ASD). This method. which relies on the classic theories of elastic behavior, measures a design's safety against two limits: an acceptable maximum stress (called allowable working stress) and a tolerable extent of deformation (deflection. stretch. erc.). These limits refer to a structure's response to service loads-that is. the loads caused by normal usage conditions. The strength me/hod, meanwhile, measures a design's adequacy against its absolute load limit-that is. when the structure must fail.To convincingly establish stress. strain. and failure limits, tests were performed extensively in the field (on real structures) and laboratories (on specimen prototypes. or models). Note: Real-world structural failures are studied both for research sake and to establish liability.In essence. the working stress method consists of designing a structure to work at some established percentage of its total capacity. The strength method consists of designing a structure tofail. but at a load condition well beyond what it should experience. Clearly the stress and strength methods arc different. but the difference is mostly procedural.The Stress Method (ASD)The stress method is as follows:1.Visualize and quantify the service (working) load conditions as intelligentlyas possible. You can make adjustments by determining statistically likelyload combinations (i.e , dead load plus live load plus wind load). consideringload duration. and so on.2.Establish standard stress. stability, and deformation limits for the variousstructural responses-in tension. bending, shear, buckling. deflection, and soon.3.Evaluate the structure's response.An advantage of working with the stress method is that you focus on the usage condition (real or anticipated). The principal disadvantage comes from your forced detachment from real failure conditions-most structures develop much different forms of stress and strain as they approach their failure limits.The Strength Method (LRFD)The strength method is as follows:1.Quantify the service loads. Then multiply them by an adjustmentfactor'( essentially a safety factor) to produce thejaclOred load.2.Visualize the various structural responses and quantify the structure'sultimate (maximum, failure) resistance in appropriate terms (resistance tocompression, buckling. bending. etc.). Sometimes this resistance is subjectto an adjustment factor, called theresistancefacror. When you employ loadand resistance factors. the strength method is now sometimes called foad andresistancefaaor design (LRFD) (see Section 5.9).pare the usable resistance ofthe structu re to the u ltirnatc resistancerequired (an investigation procedure), or a structure with an appropriateresistance is proposed (a design procedure).A major reason designers favor the strength method is that structural failure is relatively easy to test. What is an appropriate working condition is speculation. In any event, the strength method which was first developed for the design of reinforced con-crete structures, is now largely preferred in all professional design work.Nevertheless, the classic theories of clastic behavior still serve as a basis for visualizing how structures work. But ultimate responses usually vary from the classic responses, because of inelastic materials, secondary effects, multi mode responses, and so on. In other words, the usual procedure is to first consider a classic, elastic response, and then to observe (or speculate about) what happens as failure limits are approached.结构特性分析研究结构的特性在结构设计中是一个很重要的部分，它是保证设计安全性和适用性的基础。
土木工程专业外文翻译--钢筋混凝土结构设计
外文原文：Design of Reinforced Concrete StructuresSecond Edition(USA) Williams·Alan2Structure in Design of Architecture And StructuralMaterial，China Water Power Press，Beijing,2002. P37～57钢筋混凝土结构设计第二版(美)艾伦·威廉斯著第二章，在建筑学的设计构成和结构的材料，中国水利水电出版社，北京,2002.P37页～57页.Structure in Design of Architecture And Structural Material We have and the architects must deal with the spatial aspect of activity, physical, and symbolic needs in such a way that overall performance integrity is assured. Hence, he or she well wants to think of evolving a building environment as a total system of interacting and space forming subsystems. Is represents a complex challenge, and to meet it the architect will need a hierarchic design process that provides at least three levels of feedback thinking: schematic, preliminary, and final.Such a hierarchy is necessary if he or she is to avoid being confused , atconceptual stages of design thinking ,by the myriad detail issues that candistract attention from more basic considerations .In fact , we can say thatan architect’s ability to distinguish the more basic form the more detailedissues is essential to his success as a designer .The object of the schematic feed back level is to generate and evaluate overallsite-plan, activity-interaction, and building-configuration options .To do sothe architect must be able to focus on the interaction of the basic attributes of the site context, the spatial organization, and the symbolism as determinants of physical form. This means that ,in schematic terms ,the architect may first conceive and model a building design as an organizational abstraction of essential performance-space in teractions.Then he or she may explore the overall space-form implications of the abstraction. As an actual building configuration option begins to emerge, it will be modified to include consideration for basic site conditions.At the schematic stage, it would also be helpful if the designer could visualize his or her options for achieving overall structural integrity and consider the constructive feasibility and economic of his or her scheme .But this will require that the architect and/or a consultant be able to conceptualize total-system structural options in terms of elemental detail .Such overall thinking can be easily fed back to improve the space-form scheme.At the preliminary level, the architect’s emphasis will shift to the elaboration of his or her more promising schematic design options .Here the architect’s structural needs will shift to approximate design of specific subsystem options. At this stage the total structural scheme is developed to a middle level of specificity by focusing on identification and design of major subsystems to the extent that their key geometric, component, and interactive properties are established .Basic subsystem interaction and design conflicts can thus be identified and resolved in the context of total-system objectives. Consultants can play a significant part in this effort; these preliminary-level decisions may also result in feedback that calls for refinement or even major change in schematic concepts.When the designer and the client are satisfied with the feasibility of a design proposal at the preliminary level, it means that the basic problems of overall design are solved and details are not likely to produce major change .The focus shifts again ,and the design process moves into the final level .At this stagethe emphasis will be on the detailed development of all subsystem specifics . Here the role of specialists from various fields, including structural engineering, is much larger, since all detail of the preliminary design must be worked out. Decisions made at this level may produce feedback into Level II that will result in changes. However, if Levels I and II are handled with insight, the relationship between the overall decisions, made at the schematic and preliminary levels, and the specifics of the final level should be such that gross redesign is not in question, Rather, the entire process should be one of moving in an evolutionary fashion from creation and refinement (or modification) of the more general properties of a total-system design concept, to the fleshing out of requisite elements and details.To summarize: At Level I, the architect must first establish, in conceptual terms, the overall space-form feasibility of basic schematic options. At this stage, collaboration with specialists can be helpful, but only if in the form of overall thinking. At Level II, the architect must be able to identify the major subsystem requirements implied by the scheme and substantial their interactive feasibility by approximating key component properties .That is, the properties of major subsystems need be worked out only in sufficient depth to very the inherent compatibility of their basic form-related and behavioral interaction . This will mean a somewhat more specific form of collaboration with specialists then that in level I .At level III ,the architect and the specific form of collaboration with specialists then that providing for all of the elemental design specifics required to produce biddable construction documents . Of course this success comes from the development of the Structural Material. The principal construction materials of earlier times were wood and masonry brick, stone, or tile, and similar materials. The courses or layers were bound together with mortar or bitumen, a tar like substance, or some other binding agent. The Greeks and Romans sometimes used iron rods or claps to strengthen their building. The columns of the Parthenon in Athens, for example, have holes drilled in themfor iron bars that have now rusted away. The Romans also used a natural cement called puzzling, made from volcanic ash, that became as hard as stone under water. Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. Steel, basically an alloy of iron and a small amount of carbon had been made up to that time by a laborious process that restricted it to such special uses as sword blades. After the invention of the Bessemer process in 1856, steel was available in large quantities at low prices. The enormous advantage of steel is its tensile force which, as we have seen, tends to pull apart many materials. New alloys have further, which is a tendency for it to weaken as a result of continual changes in stress.Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone and clay, which is heated and then ground into a power. It is mixed at or near the construction site with sand, aggregate small stones, crushed rock, or gravel, and water to make concrete. Different proportions of the ingredients produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, the two substances complement each other.They also complement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tensions will develop. Concrete and steel also form such a strong bond─ the force that unites them─ that the steel cannot slip within the concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid. The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices. It was no longer necessary to use thickwalls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors. Both these changes served to reduce the cost of construction. It also became possible to erect buildings with greater heights and longer spans.Since the weight of modern structures is carried by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.Another advance in steel construction is the method of fastening together the beams. For many years the standard method was riveting. A rivet is a bolt with a head that looks like a blunt screw without threads. It is heated, placed in holes through the pieces of steel, and a second head is formed at the other end by hammering it to hold it in place. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting a steel material between them under high heat.Priestess’s concrete is an improved form of reinforcement. Steel rods are bent into the shapes to give them the necessary degree of tensile strengths. They are then used to priestess concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to the shapes of the steel rods. When the rods are run through the channels, they are then bonded to the concrete by filling the channels with grout, a thin mortar or binding agent. In the other (and more common) method, the priestesses steel rods are placed in the lower part of a form that corresponds to the shape of the finished structure, and the concrete is poured around them. Priestess’s concrete uses less steel and less concrete. Because it is a highly desirable material. Progressed concrete has made it possible to develop buildings with unusualshapes, like some of the modern, sports arenas, with large spaces unbroken by any obstructing supports. The uses for this relatively new structural method are constantly being developed.中文译文：在建筑学的设计构成和结构的材料我们有，并且建筑师一定在一个如此的方法中处理活动，身体检查和代号需要的空间方面全部的表现正直被保证。
土木工程(抗震)外文翻译----欧洲对钢框架结构抗震设计的评估
本科生毕业设计外文翻译题目出处/ content/b35k24747458435l/ 姓名学号 00000000学院 XX学院专业 XX工程指导教师2011年X月X日英文原文：Assessment of European seismic design proceduresfor steel framed structuresA.Y. Elghazouli1 IntroductionAlthough seismic design has benefited from substantial developments in recent years, the need to offer practical and relatively unsophisticated design procedures inevitably results in various simplifications and idealisations. These assumptions can, in some cases, have advert implications on the expected seismic performance and hence on the rationale and reliabil- ity of the design approaches. It is therefore imperative that design concepts and application rules are constantly appraised and revised in light of recent research findings and improvedunderstanding of seismic behaviour. To this end, this paper focuses on assessing the under- lying approaches and main procedures adopted in the seismic design of steel frames, with emphasis on European design provisions.In accordance with current seismic design practice, which in Europe is represented by Eurocode 8 (EC8) (2004), structures may be designed according to either non-dissipative or dissipative behaviour. The former, through which the structure is dimensioned to respond largely in the elastic range, is normally limited to areas of low seismicity or to structures of special use and importance. Otherwise, codes aim to achieve economical design by employ- ing dissipative behaviour in which considerable inelastic deformations can be accommodated under significant seismic events. In the case of irregular or complex structures, detailed non- linear dynamic analysis may be necessary. However, dissipative design of regular structures is usually performed by assigning a structural behaviour factor (i.e. force reduction or modifica- tion factor) which is used to reduce the code-specified forces resulting from idealised elastic response spectra. This is carried out in conjunction with the capacity design concept which requires an appropriate determination of the capacity of the structure based on a pre-defined plastic mechanism (often referred to as failure mode), coupled with the provision of sufficient ductility in plastic zones and adequate over-strength factors for other regions. Although the fundamental design principles of capacity design may not be purposely dissimilar in various codes, the actual procedures can often vary due to differences in behavioural assumptions and design idealisations.This paper examines the main design approaches and behavioural aspects of typical config- urations of moment-resisting and concentrically-braced frames. Although this study focuses mainly on European guidance, the discussions also refer to US provisions (AISC 1999, 2002, 2005a,b) for comparison purposes. Where appropriate, simple analytical treatments are presented in order to illustrate salient behavioural aspects and tr ends, and reference is also made to recent experimental observations and findings.Amongst the various aspects examined in this paper, particular emphasis is given to capacity design verifications as well as the implications of drift-related requirements in moment frames, and to the post-buck- ling behaviour and ductility demand in braced frames, as these represent issues that warrant cautious interpretation and consideration in the design process. Accordingly, a number of necessary clarifications and possible modifications to code procedures are put forward. 2 General considerations2.1 Limit states and loading criteriaThe European seismic code, EC8 (Eurocode 8 2004) has evolved over a number of years changing status recently from a pre-standard to a full European standard. The code explicitly adopts capacity design approaches, with its associated procedures in terms of failure mode control, force reduction and ductility requirements. One of the main merits of the code is that, in comparison with other seismic provisions, it succeeds to a large extent in maintaining a dire ct and unambiguous relationship between the specific design procedures and the overall capacity design concept.There are two fundamental design levels considered in EC8, namely ‘no-collapse’ and ‘damage-limitation’, which essentially refer to ultimate and serviceability limit states, respec- tively, under seismic loading. The no-collapse requirement corresponds to seismic action based on a recommended probability of exceedance of 10% in 50 years, or a return period of 475 years, whilst the values associated with the damage-limitation level relate to arecommended probability of 10% in 10 years, or return period of 95 years. As expected, capacity design procedures are more directly associated with the ultimate limit state, but a number of checks are included to ensure compliance with serviceability conditions.The code defines reference elastic response spectra (Se) for acceleration as a function of the period of vibration (T) and the design ground acceleration (ag) on firm ground. The elast ic spectrum depends on the soil factor (S), the damping correction factor (η) and pre-defined spectral periods (TB , TC and TD) which in turn depend on the soil type and seismic source characteristics. For ultimate limit state design, inelastic ductile performance is incorporated through the use of the behaviour factor (q) which in the last version of EC8 is assumed to capture also the effect of viscous damping. Essentially, to avoid performing inelastic analysis in design, the elastic spectral acceleration s are divided by ‘q ’ (excepting some modifications for T < TB), to reduce the design forces in accordance with the structural configuration and expected ductility. For regular structures (satisfying a number of code-specified criteria), a simplified equival ent static approach can be adopted, based largely on the fundamental mode of vibration.2.2 Behaviour factorsThis type of frame has special features that are not dealt with in this study, although some comments relevant to its behaviour are made within the discussions. Also, K-braced framesare not considered herein as they are not recommended for dissipative design. On the other hand, eccentrically-braced frames which can combine the advantages of moment-resisting and concentrically-braced frames in terms of high ductility and stiffness, are beyond the scope of this study. The reference behaviour factor should be considered as an upper bound even if non-linear dynamic analysis suggests higher values. For regular structures in areas of low seismicity, a ‘q ’ of 1.5–2.0 may be adopted without applying dissipative design procedures, recognizing the presence of a minimal level of inherent over-strength and ductility. In this case, the struc- ture would be classified as a low ductility class (DCL) for which g lobal elastic analysis can be utilized, and the resistance of members and connections may be evaluated according to EC3 (Eurocode 3 2005) without any additional requirements.中文翻译：欧洲对钢框架结构抗震设计的评估1介绍虽然抗震设计实质性进展受益匪浅,近年来,需要提供实用和相对简单的设计方法,不可避免地导致各种各样的简化和理想化。