题目
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英文原文：
Assessment of European seismic design procedures
for steel framed structures
A.Y. Elghazouli
1 Introduction
Although seismic design has bene?ted from substa ntial developments in recent years, the need to offer practical and relatively unsophisticated design procedures inevitably results in various simpli?cations 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 ?ndings 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 modi?ca- tion factor) which is used to reduce the code-speci?ed 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-de?ned plastic mechanism (often referred to as failure mode), coupled with the provision of suf?cient 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 con?g- 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 trends, and reference is also made to recent experimental observations and ?ndings. Amongst the various aspects examined in this paper, particular emphasis is given to capacity design veri?cations 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 clari?cations and possible modi?cations to code procedures are put forward. 2 General considerations
2.1 Limit states and loading criteria
The 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 speci?c 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 de?nes reference elastic response spectra (Se) for acceleration as a function of the period of vibration (T) and the design ground acceleration (ag) on ?rm ground. The elast ic spectrum depends on the soil factor (S), the damping correction factor (η) and pre-de?ned 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 modi?cations for T < TB), to reduce the design forces in accordance with the structural con?guration and expected ductility. For regular structures (satisfying a number of code-speci?ed criteria), a simpli?ed equival ent static approach can be adopted, based largely on the fundamental mode of vibration.
2.2 Behaviour factors
This 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 frames are 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 classi?ed 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。这些假设,某些情况下,有广告影响预期的抗震性能,因此在合理性和可靠性设计的方法下。有必要的设计概念和应用不断评估和修改规则是根据最近的研究和对地震的行为改进的理解。为此,本文在评估潜在的方法和主要流程采用钢结构工程的抗震设计中,用强调欧洲设计规定,制定本规定。
按照现行的抗震设计实践,这在欧洲被表示Eurocode 8(EC8)(2004),结构也可以设计出系统根据或耗散行为。这位前,藉此结构尺寸进行回应主要集中在弹性范围内,通常是有限的地区地震活动或结构的低特殊用途与重要性。否则,编码的目的是要实现节约型设计被耗散行为在相当大的弹性变形能得到满足在重大的地震事件。在案件的不规则或复杂的结构,详细的非-线性动态的分析可能是必要的。然而,常规结构设计的系统具有耗散通过指定一个经常表演结构行为因素(例如力量还原或修改因素),用它来减少所造成的指定代码，正如有弹性响应谱。这是进行结合的能力设计概念,需要采用一种适宜的容量的确定基于一个预先定义的结构塑料机械(通常称为失效模式),伴随着提供充分的在塑性区和足够的延性等因素为其它地区。虽然基本设计原则的能力设计可能不是故意在各种不同实际的程序代码,可以在常随因为不同的行为假设理想化和理想化设计。
摘要本文检视主要设计方法和行为方面的抗力矩典型配置和中心支撑帧。虽然这项研究主要在欧洲的指导下,我们的讨论也涉及到规定(以1999年,2002年,2003 2005a,b作比较)。在适当的地方,简单的解析治疗，为了说明了引人注目的行为方面和发展趋势参考。最近的实验观测也做了各种努力和成果。重点是给设计验证作为相关要求的含义,时刻帧后屈曲行为和延性需求的支撑框架,因为这些代表问题,谨慎的解释和考虑的设计过程。因此,一定数量的必要的澄清和可能的修改代码程序提出了2种通常的考虑。
2.1极限状态和加载的标准
欧洲的抗震规范,EC8(Eurocode 8 2004年)已经进化数年，最近从一个准标准地位改变了欧洲标准。代码明确采用能力设计方法,及相应程序方面的失效方式控制力的减少和延性需求。其中最主要的优点是相比于其它地震规定,它的成功在很大程度上在维持直接和明确的关系设计的具体程序和整体能力设计的概念。
有两个基本的设计水平,即考虑无倒塌'和損害降低,实质上是指最终和极限状态,分别,地震作用下。无倒塌技术对应的地震作用的要求推荐的概率
的基础上对10%在未来的50年里, 或重现期公元前475年的价值观,而与之关联的損害降低水平相关的概率是赞扬10%在10年内,或重现期95年了。正如人们所预料的那样,能力设计的程序都被更直接地联系在一起的极限状态,但都包含了大量的检查,以确保符合适用性条件。这个时期的振动(T)和设计地面加速度(ag)在坚固的地面上。弹性频谱取决于土壤因子(S),阻尼校正因子(η)和预案光谱周期(肺结核,血中总胆固醇及TD)依次取决于土壤类型
和地震的来源特征。最终的极限状态设计,为球墨铸铁性能无弹性拌匀通过使用此行为因子(q),在过去的版本的EC8是假定捕获作用阻尼。从本质上说,为了避免表演无弹性分析在设计、弹性谱加速度被“问”(除某些修改为T < TB)、降低设计力量依照结构配置和预期的延性。常规结构(满足一定数量的指定代码准则),一个简化的等效静态方法可采用主要基于的基本模式振动。
2.2行为因素
在这项研究中,虽然有些评论有关它的行为是在讨论。同时,k形帧的,
没有考虑到在内,因为它们是不推荐使用对耗散的设计。另一方面,特别支撑帧,抗力矩可以结合的优点和同心支撑帧在条款高延性和刚度的都超出了本研究的范围。参考行为因素应该被视为一个上界即使非线性的动态分析提出更高的价值。常规结构领域的,低地震活动性的方式,也可采用无申请1.5 - 2.0设计程序,认识到耗散一个最低水平的存在固有的超负荷和延性。在这种情况下,构成的-真正的会被视作是延展性差(DCL),在全球弹性分析即可被
利用,和电阻的成员和连接端口可以评价根据2005年Eurocode EC3(3),没有任何附加要求。
项目成本控制 一、引言 项目是企业形象的窗口和效益的源泉。随着市场竞争日趋激烈，工程质量、文明施工要求不断提高，材料价格波动起伏，以及其他种种不确定因素的影响，使得项目运作处于较为严峻的环境之中。由此可见项目的成本控制是贯穿在工程建设自招投标阶段直到竣工验收的全过程，它是企业全面成本管理的重要环节，必须在组织和控制措施上给于高度的重视，以期达到提高企业经济效益的目的。 二、概述 工程施工项目成本控制，指在项目成本在成本发生和形成过程中，对生产经营所消耗的人力资源、物资资源和费用开支，进行指导、监督、调节和限制，及时预防、发现和纠正偏差从而把各项费用控制在计划成本的预定目标之内，以达到保证企业生产经营效益的目的。 三、施工企业成本控制原则 施工企业的成本控制是以施工项目成本控制为中心，施工项目成本控制原则是企业成本管理的基础和核心，施工企业项目经理部在对项目施工过程进行成本控制时，必须遵循以下基本原则。 3.1 成本最低化原则。施工项目成本控制的根本目的，在于通过成本管理的各种手段，促进不断降低施工项目成本，以达到可能实现最低的目标成本的要求。在实行成本最低化原则时，应注意降低成本的可能性和合理的成本最低化。一方面挖掘各种降低成本的能力，使可能性变为现实；另一方面要从实际出发，制定通过主观努力可能达到合理的最低成本水平。 3.2 全面成本控制原则。全面成本管理是全企业、全员和全过程的管理，亦称“三全”管理。项目成本的全员控制有一个系统的实质性内容，包括各部门、各单位的责任网络和班组经济核算等等，应防止成本控制人人有责，人人不管。项目成本的全过程控制要求成本控制工作要随着项目施工进展的各个阶段连续 进行，既不能疏漏，又不能时紧时松，应使施工项目成本自始至终置于有效的控制之下。 3.3 动态控制原则。施工项目是一次性的，成本控制应强调项目的中间控制，即动态控制。因为施工准备阶段的成本控制只是根据施工组织设计的具体内容确
PA VEMENT PROBLEMS CAUSED BY COLLAPSIBLE SUBGRADES By Sandra L. Houston,1 Associate Member, ASCE (Reviewed by the Highway Division) ABSTRACT: Problem subgrade materials consisting of collapsible soils are com- mon in arid environments, which have climatic conditions and depositional and weathering processes favorable to their formation. Included herein is a discussion of predictive techniques that use commonly available laboratory equipment and testing methods for obtaining reliable estimates of the volume change for these problem soils. A method for predicting relevant stresses and corresponding collapse strains for typical pavement subgrades is presented. Relatively simple methods of evaluating potential volume change, based on results of familiar laboratory tests, are used. INTRODUCTION When a soil is given free access to water, it may decrease in volume, increase in volume, or do nothing. A soil that increases in volume is called a swelling or expansive soil, and a soil that decreases in volume is called a collapsible soil. The amount of volume change that occurs depends on the soil type and structure, the initial soil density, the imposed stress state, and the degree and extent of wetting. Subgrade materials comprised of soils that change volume upon wetting have caused distress to highways since the be- ginning of the professional practice and have cost many millions of dollars in roadway repairs. The prediction of the volume changes that may occur in the field is the first step in making an economic decision for dealing with these problem subgrade materials. Each project will have different design considerations, economic con- straints, and risk factors that will have to be taken into account. However, with a reliable method for making volume change predictions, the best design relative to the subgrade soils becomes a matter of economic comparison, and a much more rational design approach may be made. For example, typical techniques for dealing with expansive clays include: (1) In situ treatments with substances such as lime, cement, or fly-ash; (2) seepage barriers and/ or drainage systems; or (3) a computing of the serviceability loss and a mod- ification of the design to "accept" the anticipated expansion. In order to make the most economical decision, the amount of volume change (especially non- uniform volume change) must be accurately estimated, and the degree of road roughness evaluated from these data. Similarly, alternative design techniques are available for any roadway problem. The emphasis here will be placed on presenting economical and simple methods for: (1) Determining whether the subgrade materials are collapsible; and (2) estimating the amount of volume change that is likely to occur in the 'Asst. Prof., Ctr. for Advanced Res. in Transp., Arizona State Univ., Tempe, AZ 85287. Note. Discussion open until April 1, 1989. To extend the closing date one month,
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
(文档含英文原文和中文翻译) 中英文对照外文翻译 基于拉格朗日乘数法的框架结构合理线刚度比的研究 【摘要】框架结构是一种常见的多层高层建筑结构；列的合理线刚度比研究是框架结构优化设计中的一个重要方面。本论文研究合理线刚度比时，框架梁、柱的
侧移刚度根据拉格朗日乘数法结构优化的理论和在框架梁、柱的总物质的量一定的前提下，取得最高值。与传统的估计方法和试算梁柱截面尺寸不同，梁、柱的合理的截面尺寸可以在初步设计阶段由派生的公式计算。这种方法不仅作为计算框架梁、柱的截面尺寸基础，确认初步设计阶，而且也被用做类似的结构梁柱合理线刚度比研究的参考。此外，在调整帧梁、柱的截面尺寸的方法的基础上，降低柱的轴向的压缩比，从而达到剪切压缩比和提高结构的延展性。 【关键词】拉格朗日数乘法框架结构刚度比截面尺寸 1 引言 在混凝土框架结构初步设计的期间，通常，框架梁截面高度通过跨度来估算，和截面宽度根据高宽比估算; 框架柱的截面尺寸是根据柱轴压缩的支持柱的面积的比率估算[1]。然而，在估计过程中，初步设计阶段中的一个重要的链，未考虑到柱侧移刚度的影响[2]。列侧移刚度越大，结构层间位的刚度越大，剪切型框架结构的层间位移将越较小。所以，总结构越小的侧向位移将减少地震灾害[3] 所造成的损失。论文的核心是如何得到列侧移刚度的最大值。 同时，列侧移刚度的值与框架梁-柱线刚度直接相关。本论文的目的是为了得到一个合理的框架梁 - 柱的线刚度比，在某个控制范围内获得列侧移刚度的最大值。 计算列横向位移的方法有两种方法：刚度拐点点法和修改拐点法。拐点的方法假定关节的旋转角度为0（当梁柱线性刚度比是大于或等于3时，柱的上端和下端的关节的旋转角度可以取为0，因为它实际上是相当小），即梁的弯曲刚性被视为无穷大。拐点的方法主要是应用于具有比较少层的框架结构。但对于多层、高层框架结构，增加柱截面会导致梁柱线刚度比小于3，在水平荷载作用下，框架结构的所有关节的旋转角度的横向位移会发生不可忽视。因此，一位日本教授武藤提出修改拐点法[4]，即D-值方法。本文采用D-值列侧移刚度的计算法，因为它着重于多层、高层框架结构。 少数在国内外对框架梁柱合理线刚度比的研究，只有梁七黹，源于列侧移刚度的计算方法，比D-值法更加应用广泛；申得氏指出在多层、高层框架结构的柱侧向刚度计算中存在的问题，补充和修改底部和顶部层的列侧向刚度计算公式;
专业资料 学院： 专业：土木工程 姓名： 学号： 外文出处：Structural Systems to resist (用外文写) Lateral loads 附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 抗侧向荷载的结构体系 常用的结构体系 若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。 这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。 如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类： 1.抗弯矩框架。 2.支撑框架，包括偏心支撑框架。 3.剪力墙，包括钢板剪力墙。 4.筒中框架。 5.筒中筒结构。 6.核心交互结构。 7. 框格体系或束筒体系。 特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。 将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并
不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。 虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。 抗弯矩框架 抗弯矩框架也许是低，中高度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。 我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。 支撑框架 支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。
姓名： 学号： 10447425 X X 大学 毕业设计（论文）外文翻译 （2014届） 外文题目Developments in excavation bracing systems 译文题目开挖工程支撑体系的发展 外文出处Tunnelling and Underground Space Technology 31 (2012) 107–116 学生XXX 学院XXXX 专业班级XXXXX 校内指导教师XXX 专业技术职务XXXXX 校外指导老师专业技术职务 二○一三年十二月
开挖工程支撑体系的发展 1.引言 几乎所有土木工程建设项目（如建筑物，道路，隧道，桥梁，污水处理厂，管道，下水道）都涉及泥土挖掘的一些工程量。往往由于由相邻的结构，特性线，或使用权空间的限制，必须要一个土地固定系统，以允许土壤被挖掘到所需的深度。历史上，许多挖掘支撑系统已经开发出来。其中，现在比较常见的几种方法是：板桩，钻孔桩墙，泥浆墙。 土地固定系统的选择是由技术性能要求和施工可行性（例如手段，方法）决定的，包括执行的可靠性，而成本考虑了这些之后，其他问题也得到解决。通常环境后果（用于处理废泥浆和钻井液如监管要求）也非常被关注（邱阳、1998）。 土地固定系统通常是建设项目的较大的一个组成部分。如果不能按时完成项目，将极大地影响总成本。通常首先建造支撑，在许多情况下，临时支撑系统是用于支持在挖掘以允许进行不断施工，直到永久系统被构造。临时系统可以被去除或留在原处。 打桩时，因撞击或振动它们可能会被赶入到位。在一般情况下，振动是最昂贵的方法，但只适合于松散颗粒材料，土壤中具有较高电阻（例如，通过鹅卵石）的不能使用。采用打入桩系统通常是中间的成本和适合于软沉积物（包括粘性和非粘性），只要该矿床是免费的鹅卵石或更大的岩石。 通常，垂直元素（例如桩）的前安装挖掘工程和水平元件（如内部支撑或绑回）被安装为挖掘工程的进行下去，从而限制了跨距长度，以便减少在垂直开发弯矩元素。在填充情况下，桩可先设置，从在斜坡的底部其嵌入悬挑起来，安装作为填充进步水平元素（如搭背或土钉）。如果滞后是用来保持垂直元素之间的土壤中，它被安装为挖掘工程的进行下去，或之前以填补位置。 吉尔- 马丁等人（2010）提供了一个数值计算程序，以获取圆形桩承受轴向载荷和统一标志（如悬臂桩）的单轴弯矩的最佳纵筋。他们开发的两种优化流程：用一个或两个直径为纵向钢筋。优化增强模式允许大量减少的设计要求钢筋的用量，这些减少纵向钢筋可达到50％相对传统的，均匀分布的加固方案。 加固桩集中纵向钢筋最佳的位置在受拉区。除了节约钢筋，所述非对称加强钢筋图案提高抗弯刚度，通过增加转动惯量的转化部分的时刻。这种增加的刚性可能会在一段时间内增加的变形与蠕变相关的费用。评估相对于传统的非对称加强桩的优点，对称，钢筋桩被服务的条件下全面测试来完成的，这种试验是为了验证结构的可行性和取得的变形的原位测量。 基于现场试验中，用于优化的加强图案的优点浇铸钻出孔（CIDH）在巴塞罗那的
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
（ 二 〇 一 二 年 六 月 外文文献及翻译 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 of prevention and processing Abstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processing Foreword Concrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The 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 endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the
英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,
毕业设计(论文)外文资料翻译 系：机械工程系 专业：土木工程 姓名： 学号： 外文出处：Design of prestressed (用外文写) concrete structures 附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 8-2简支梁布局 一个简单的预应力混凝土梁由两个危险截面控制：最大弯矩截面和端截面。这两部分设计好之后，中间截面一定要单独检查，必要时其他部位也要单独调查。最大弯矩截面在以下两种荷载阶段为控制情况，即传递时梁受最小弯矩M G的初始阶段和最大设计弯矩M T时的工作荷载阶段。而端截面则由抗剪强度、支承垫板、锚头间距和千斤顶净空所需要的面积来决定。所有的中间截面是由一个或多个上述要求，根它们与上述两种危险截面的距离来控制。对于后张构件的一种常见的布置方式是在最大弯矩截面采用诸如I形或T形的截面，而在接近梁端处逐渐过渡到简单的矩形截面。这就是人们通常所说的后张构件的端块。对于用长线法生产的先张构件，为了便于生产，全部只用一种等截面，其截面形状则可以为I形、双T形或空心的。在第5 、 6 和7章节中已经阐明了个别截面的设计，下面论述简支梁钢索的总布置。 梁的布置可以用变化混凝土和钢筋的办法来调整。混凝土的截面在高度、宽度、形状和梁底面或者顶面的曲率方面都可以有变化。而钢筋只在面积方面有所变化，不过在相对于混凝土重心轴线的位置方面却多半可以有变化。通过调整这些变化因素，布置方案可能有许多组合，以适应不同的荷载情况。这一点是与钢筋混凝土梁是完全不同的，在钢筋混凝土梁的通常布置中，不是一个统一的矩形截面便是一个统一的T形，而钢筋的位置总是布置得尽量靠底面纤维。 首先考虑先张梁，如图 8-7，这里最好采用直线钢索，因为它们在两个台座之间加力比较容易。我们先从图（a）的等截面直梁的直线钢索开始讨论。这样的布置都很简单，但这样一来，就不是很经济的设计了，因为跨中和梁端的要求会产生冲突。通常发生在跨度中央的最大弯矩截面中的钢索，最好尽量放低，以便尽可能提供最大力臂而提供最大的内部抵制力矩。当跨度中央的梁自重弯矩M G相当大时，就可以把c.g.s布置在截面核心范围以下很远的地方，而不致在传递时在顶部纤维中引起拉应力。然而对于梁端截面却有一套完全不同的要求。由于在梁端没有外力矩，因为在最后的时刻，安排钢索要以c.g.s与 c.g.c在结束区段一致，如此同样地获得克服压力分配的方法。无论如何，如果张应力在最后不能承受，放置 c.g.s.
学校 毕业设计（论文）附件 外文文献翻译 学号： xxxxx 姓名： xxx 所在系别： xxxxx 专业班级： xxx 指导教师： xxxx 原文标题： Building construction concrete crack of prevention and processing 2012年月日 .
建筑施工混凝土裂缝的预防与处理1 摘要 混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。 关键词：混凝土裂缝预防处理 前言 混凝土是一种由砂石骨料、水泥、水及其他外加材料混合而形成的非均质脆性材料。由于混凝土施工和本身变形、约束等一系列问题，硬化成型的混凝土中存在着众多的微孔隙、气穴和微裂缝，正是由于这些初始缺陷的存在才使混凝土呈现出一些非均质的特性。微裂缝通常是一种无害裂缝，对混凝土的承重、防渗及其他一些使用功能不产生危害。但是在混凝土受到荷载、温差等作用之后，微裂缝就会不断的扩展和连通，最终形成我们肉眼可见的宏观裂缝，也就是混凝土工程中常说的裂缝。 混凝土建筑和构件通常都是带缝工作的，由于裂缝的存在和发展通常会使内部的钢筋等材料产生腐蚀，降低钢筋混凝土材料的承载能力、耐久性及抗渗能力，影响建筑物的外观、使用寿命，严重者将会威胁到人们的生命和财产安全。很多工程的失事都是由于裂缝的不稳定发展所致。近代科学研究和大量的混凝土工程实践证明，在混凝土工程中裂缝问题是不可避免的，在一定的范围内也是可以接受的，只是要采取有效的措施将其危害程度控制在一定的范围之内。钢筋混凝土规范也明确规定：有些结构在所处的不同条件下，允许存在一定宽度的裂缝。但在施工中应尽量采取有效措施控制裂缝产生，使结构尽可能不出现裂缝或尽量减少裂缝的数量和宽度，尤其要尽量避免有害裂缝的出现，从而确保工程质量。 混凝土裂缝产生的原因很多，有变形引起的裂缝：如温度变化、收缩、膨胀、不均匀沉陷等原因引起的裂缝；有外载作用引起的裂缝；有养护环境不当和化学作用引起的裂缝等等。在实际工程中要区别对待，根据实际情况解决问题。 混凝土工程中常见裂缝及预防: 1.干缩裂缝及预防 干缩裂缝多出现在混凝土养护结束后的一段时间或是混凝土浇筑完毕后的一周左右。水泥浆中水分的蒸发会产生干缩，且这种收缩是不可逆的。干缩裂缝的产生主要是由于混凝土内外水分蒸发程度不同而导致变形不同的结果：混凝土受外部条件的影响，表面水分损失过快，变形较大，内部湿度变化较小变形较小，较大的表面干缩变形受到混凝土内部约束，产生较大拉应力而产生裂缝。相对湿度越低，水泥浆体干缩越大，干缩裂缝越易产 1原文出处及作者：《加拿大土木工程学报》
7 Rigid-Frame Structures A rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders. The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rig id frames are considered economical for buildings of up to' about 25 stories, above which their drift resistance is costly to control. If, however, a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components. As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically inc lude the following stages: 1. Estimation of gravity load forces in girders and columns by approximate method. 2. Preliminary estimate of member sizes based on gravity load forces with arbitrary increase in sizes to allow for horizontal loading. 3. Approximate allocation of horizontal loading to bents and preliminary analysis of member forces in bents. 4. Check on drift and adjustment of member sizes if necessary. 5. Check on strength of members for worst combination of gravity and horizontal loading, and adjustment of member sizes if necessary. 6. Computer analysis of total structure for more accurate check on member strengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift.. 7. Detailed design of members and connections.