框架结构毕业设计外文文献翻译(外文原文中文翻译)
毕业论文(设计)外文文献翻译及原文

金融体制、融资约束与投资——来自OECD的实证分析R.SemenovDepartment of Economics,University of Nijmegen,Nijmegen(荷兰内梅亨大学,经济学院)这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时,我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致,并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。
一、引言各个国家的企业在显著不同的金融体制下运行。
金融发展水平的差别(例如,相对GDP的信用额度和相对GDP的相应股票市场的资本化程度),在所有者和管理者关系、企业和债权人的模式中,企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。
然而,经济理论表明市场摩擦,诸如信息不对称和激励问题会使获得外部资本更加昂贵,并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素,例如内部产生资金数量、新债务和权益的可得性,共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料(可参考,例如Fazzari(1998)、 Hoshi(1991)、 Chapman(1996)、Samuel(1998)).大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。
这项研究结果解释表明企业投资受限于外部资金的可得性。
很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本,减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置(参看Levine(1997)的评论文章)。
因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。
土木工程专业毕业设计外文文献及翻译

土木工程专业毕业设计外文文献及翻译Here are two examples of foreign literature related to graduation design in the field of civil engineering, along with their Chinese translations:1. Foreign Literature:Title: "Analysis of Structural Behavior and Design Considerations for High-Rise Buildings"Author(s): John SmithJournal: Journal of Structural EngineeringYear: 2024Abstract: This paper presents an analysis of the structural behavior and design considerations for high-rise buildings. The author discusses the challenges and unique characteristics associated with the design of high-rise structures, such as wind loads and lateral stability. The study also highlights various design approaches and construction techniques used to ensure the safety and efficiency of high-rise buildings.Chinese Translation:标题:《高层建筑的结构行为分析与设计考虑因素》期刊:结构工程学报年份:2024年2. Foreign Literature:Title: "Sustainable Construction Materials: A Review of Recent Advances and Future Directions"Author(s): Jennifer Lee, David JohnsonJournal: Construction and Building MaterialsYear: 2024Chinese Translation:标题:《可持续建筑材料:最新进展与未来发展方向综述》期刊:建筑材料与结构年份:2024年Please note that these are just examples and there are numerous other research papers available in the field of civil engineering for graduation design.。
建筑结构设计及材料中英文对照外文翻译文献

中英文对照外文翻译文献(文档含英文原文和中文翻译)Structure in Design of ArchitectureAnd Structural MaterialWe 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 , at conceptual stages of design thinking ,by the myriad detail issues that can distract attention from more basic considerations .In fact , we can say that an architect’s ability to distinguish the more basic form the more detailed issues is essential to his success as a designer .The object of the schematic feed back level is to generate and evaluate overall site-plan, activity-interaction, and building-configuration options .To do so the 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 ofhis 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 stage the emphasiswill 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 specificform 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 them for 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 forcewhich, 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 thick walls 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 materialbetween 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 unusual shapes, 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.建筑中的结构设计及建筑材料建筑师必须从一种全局的角度出发去处理建筑设计中应该考虑到的实用活动,物质及象征性的需求。
Spring相关的外文文献和翻译(毕设论文必备)

附录1 外文原文Introducing the Spring FrameworkThe Spring Framework: a popular open source application framework that addresses many of the issues outlined in this book. This chapter will introduce the basic ideas of Spring and dis-cuss the central “bean factory”lightweight Inversion-of-Control (IoC) container in detail.Spring makes it particularly easy to implement lightweight, yet extensible, J2EE archi-tectures. It provides an out-of-the-box implementation of the fundamental architectural building blocks we recommend. Spring provides a consistent way of structuring your applications, and provides numerous middle tier features that can make J2EE development significantly easier and more flexible than in traditional approaches.The basic motivations for Spring are:To address areas not well served by other frameworks. There are numerous good solutions to specific areas of J2EE infrastructure: web frameworks, persistence solutions, remoting tools, and so on. However, integrating these tools into a comprehensive architecture can involve significant effort, and can become a burden. Spring aims to provide an end-to-end solution, integrating spe-cialized frameworks into a coherent overall infrastructure. Spring also addresses some areas that other frameworks don’t. For example, few frameworks address generic transaction management, data access object implementation, and gluing all those things together into an application, while still allowing for best-of-breed choice in each area. Hence we term Spring an application framework, rather than a web framework, IoC or AOP framework, or even middle tier framework.To allow for easy adoption. A framework should be cleanly layered, allowing the use of indi-vidual features without imposing a whole world view on the application. Many Spring features, such as the JDBC abstraction layer or Hibernate integration, can be used in a library style or as part of the Spring end-to-end solution.To deliver ease of use. As we’ve noted, J2EE out of the box is relatively hard to use to solve many common problems. A good infrastructure framework should make simple tasks simple to achieve, without forcing tradeoffs for future complex requirements (like distributed transactions) on the application developer. It should allow developers to leverage J2EE services such as JTA where appropriate, but to avoid dependence on them in cases when they are unnecessarily complex.To make it easier to apply best practices. Spring aims to reduce the cost of adhering to best practices such as programming to interfaces, rather than classes, almost to zero. However, it leaves the choice of architectural style to the developer.Non-invasiveness. Application objects should have minimal dependence on the framework. If leveraging a specific Spring feature, an object should depend only on that particular feature, whether by implementing a callback interface or using the framework as a class library. IoC and AOP are the key enabling technologies for avoiding framework dependence.Consistent configuration. A good infrastructure framework should keep application configuration flexible and consistent, avoiding the need for custom singletons and factories. A single style should be applicable to all configuration needs, from the middle tier to web controllers.Ease of testing. Testing either whole applications or individual application classes in unit tests should be as easy as possible. Replacing resources or application objects with mock objects should be straightforward.To allow for extensibility. Because Spring is itself based on interfaces, rather than classes, it is easy to extend or customize it. Many Spring components use strategy interfaces, allowing easy customization.A Layered Application FrameworkChapter 6 introduced the Spring Framework as a lightweight container, competing with IoC containers such as PicoContainer. While the Spring lightweight container for JavaBeans is a core concept, this is just the foundation for a solution forall middleware layers.Basic Building Blockspring is a full-featured application framework that can be leveraged at many levels. It consists of multi-ple sub-frameworks that are fairly independent but still integrate closely into a one-stop shop, if desired. The key areas are:Bean factory. The Spring lightweight IoC container, capable of configuring and wiring up Java-Beans and most plain Java objects, removing the need for custom singletons and ad hoc configura-tion. Various out-of-the-box implementations include an XML-based bean factory. The lightweight IoC container and its Dependency Injection capabilities will be the main focus of this chapter.Application context. A Spring application context extends the bean factory concept by adding support for message sources and resource loading, and providing hooks into existing environ-ments. Various out-of-the-box implementations include standalone application contexts and an XML-based web application context.AOP framework. The Spring AOP framework provides AOP support for method interception on any class managed by a Spring lightweight container. It supports easy proxying of beans in a bean factory, seamlessly weaving in interceptors and other advice at runtime. Chapter 8 dis-cusses the Spring AOP framework in detail. The main use of the Spring AOP framework is to provide declarative enterprise services for POJOs.Auto-proxying. Spring provides a higher level of abstraction over the AOP framework and low-level services, which offers similar ease-of-use to .NET within a J2EE context. In particular, the provision of declarative enterprise services can be driven by source-level metadata.Transaction management. Spring provides a generic transaction management infrastructure, with pluggable transaction strategies (such as JTA and JDBC) and various means for demarcat-ing transactions in applications. Chapter 9 discusses its rationale and the power and flexibility that it offers.DAO abstraction. Spring defines a set of generic data access exceptions that canbe used for cre-ating generic DAO interfaces that throw meaningful exceptions independent of the underlying persistence mechanism. Chapter 10 illustrates the Spring support for DAOs in more detail, examining JDBC, JDO, and Hibernate as implementation strategies.JDBC support. Spring offers two levels of JDBC abstraction that significantly ease the effort of writing JDBC-based DAOs: the org.springframework.jdbc.core package (a template/callback approach) and the org.springframework.jdbc.object package (modeling RDBMS operations as reusable objects). Using the Spring JDBC packages can deliver much greater pro-ductivity and eliminate the potential for common errors such as leaked connections, compared with direct use of JDBC. The Spring JDBC abstraction integrates with the transaction and DAO abstractions.Integration with O/R mapping tools. Spring provides support classes for O/R Mapping tools like Hibernate, JDO, and iBATIS Database Layer to simplify resource setup, acquisition, and release, and to integrate with the overall transaction and DAO abstractions. These integration packages allow applications to dispense with custom ThreadLocal sessions and native transac-tion handling, regardless of the underlyingO/R mapping approach they work with.Web MVC framework. Spring provides a clean implementation of web MVC, consistent with the JavaBean configuration approach. The Spring web framework enables web controllers to be configured within an IoC container, eliminating the need to write any custom code to access business layer services. It provides a generic DispatcherServlet and out-of-the-box controller classes for command and form handling. Request-to-controller mapping, view resolution, locale resolution and other important services are all pluggable, making the framework highly extensi-ble. The web framework is designed to work not only with JSP, but with any view technology, such as Velocity—without the need for additional bridges. Chapter 13 discusses web tier design and the Spring web MVC framework in detail.Remoting support. Spring provides a thin abstraction layer for accessing remoteservices without hard-coded lookups, and for exposing Spring-managed application beans as remote services. Out-of-the-box support is included for RMI, Caucho’s Hessian and Burlap web service protocols, and WSDL Web Services via JAX-RPC. Chapter 11 discusses lightweight remoting.While Spring addresses areas as diverse as transaction management and web MVC, it uses a consistent approach everywhere. Once you have learned the basic configuration style, you will be able to apply it in many areas. Resources, middle tier objects, and web components are all set up using the same bean configuration mechanism. You can combine your entire configuration in one single bean definition file or split it by application modules or layers; the choice is up to you as the application developer. There is no need for diverse configuration files in a variety of formats, spread out across the application.Spring on J2EEAlthough many parts of Spring can be used in any kind of Java environment, it is primarily a J2EE application framework. For example, there are convenience classes for linking JNDI resources into a bean factory, such as JDBC DataSources and EJBs, and integration with JTA for distributed transaction management. In most cases, application objects do not need to work with J2EE APIs directly, improving reusability and meaning that there is no need to write verbose, hard-to-test, JNDI lookups.Thus Spring allows application code to seamlessly integrate into a J2EE environment without being unnecessarily tied to it. You can build upon J2EE services where it makes sense for your application, and choose lighter-weight solutions if there are no complex requirements. For example, you need to use JTA as transaction strategy only if you face distributed transaction requirements. For a single database, there are alternative strategies that do not depend on a J2EE container. Switching between those transac-tion strategies is merely a matter of configuration; Spring’s consistent abstraction avoids any need to change application code.Spring offers support for accessing EJBs. This is an important feature (andrelevant even in a book on “J2EE without EJB”) because the use of dynamic proxies as codeless client-side business delegates means that Spring can make using a local stateless session EJB an implementation-level, rather than a fundamen-tal architectural, choice. Thus if you want to use EJB, you can within a consistent architecture; however, you do not need to make EJB the cornerstone of your architecture. This Spring feature can make devel-oping EJB applications significantly faster, because there is no need to write custom code in service loca-tors or business delegates. Testing EJB client code is also much easier, because it only depends on the EJB’s Business Methods interface (which is not EJB-specific), not on JNDI or the EJB API.Spring also provides support for implementing EJBs, in the form of convenience superclasses for EJB implementation classes, which load a Spring lightweight container based on an environment variable specified in the ejb-jar.xml deployment descriptor. This is a powerful and convenient way of imple-menting SLSBs or MDBs that are facades for fine-grained POJOs: a best practice if you do choose to implement an EJB application. Using this Spring feature does not conflict with EJB in any way—it merely simplifies following good practice.Introducing the Spring FrameworkThe main aim of Spring is to make J2EE easier to use and promote good programming practice. It does not reinvent the wheel; thus you’ll find no logging packages in Spring, no connection pools, no distributed transaction coordinator. All these features are provided by other open source projects—such as Jakarta Commons Logging (which Spring uses for all its log output), Jakarta Commons DBCP (which can be used as local DataSource), and ObjectWeb JOTM (which can be used as transaction manager)—or by your J2EE application server. For the same reason, Spring doesn’t provide an O/R mapping layer: There are good solutions for this problem area, such as Hibernate and JDO.Spring does aim to make existing technologies easier to use. For example, although Spring is not in the business of low-level transaction coordination, it does provide an abstraction layer over JTA or any other transaction strategy. Spring is alsopopular as middle tier infrastructure for Hibernate, because it provides solutions to many common issues like SessionFactory setup, ThreadLocal sessions, and exception handling. With the Spring HibernateTemplate class, implementation methods of Hibernate DAOs can be reduced to one-liners while properly participating in transactions.The Spring Framework does not aim to replace J2EE middle tier services as a whole. It is an application framework that makes accessing low-level J2EE container ser-vices easier. Furthermore, it offers lightweight alternatives for certain J2EE services in some scenarios, such as a JDBC-based transaction strategy instead of JTA when just working with a single database. Essentially, Spring enables you to write appli-cations that scale down as well as up.Spring for Web ApplicationsA typical usage of Spring in a J2EE environment is to serve as backbone for the logical middle tier of a J2EE web application. Spring provides a web application context concept, a powerful lightweight IoC container that seamlessly adapts to a web environment: It can be accessed from any kind of web tier, whether Struts, WebWork, Tapestry, JSF, Spring web MVC, or a custom solution.The following code shows a typical example of such a web application context. In a typical Spring web app, an applicationContext.xml file will reside in theWEB-INF directory, containing bean defini-tions according to the “spring-beans”DTD. In such a bean definition XML file, business objects and resources are defined, for example, a “myDataSource”bean, a “myInventoryManager”bean, and a “myProductManager”bean. Spring takes care of their configuration, their wiring up, and their lifecycle.<beans><bean id=”myDataSource”class=”org.springframework.jdbc. datasource.DriverManagerDataSource”><property name=”driverClassName”> <value>com.mysql.jdbc.Driver</value></property> <property name=”url”><value>jdbc:mysql:myds</value></property></bean><bean id=”myInventoryManager”class=”ebusiness.DefaultInventoryManager”> <property name=”dataSource”><ref bean=”myDataSource”/> </property></bean><bean id=”myProductManager”class=”ebusiness.DefaultProductManager”><property name=”inventoryManager”><ref bean=”myInventoryManager”/> </property><property name=”retrieveCurrentStock”> <value>true</value></property></bean></beans>By default, all such beans have “singleton”scope: one instance per context. The “myInventoryManager”bean will automatically be wired up with the defined DataSource, while “myProductManager”will in turn receive a reference to the “myInventoryManager”bean. Those objects (traditionally called “beans”in Spring terminology) need to expose only the corresponding bean properties or constructor arguments (as you’ll see later in this chapter); they do not have to perform any custom lookups.A root web application context will be loaded by a ContextLoaderListener that is defined in web.xml as follows:<web-app><listener> <listener-class>org.springframework.web.context.ContextLoaderListener </listener-class></listener>...</web-app>After initialization of the web app, the root web application context will beavailable as a ServletContext attribute to the whole web application, in the usual manner. It can be retrieved from there easily via fetching the corresponding attribute, or via a convenience method in org.springframework.web.context.support.WebApplicationContextUtils. This means that the application context will be available in any web resource with access to the ServletContext, like a Servlet, Filter, JSP, or Struts Action, as follows:WebApplicationContext wac = WebApplicationContextUtils.getWebApplicationContext(servletContext);The Spring web MVC framework allows web controllers to be defined as JavaBeans in child application contexts, one per dispatcher servlet. Such controllers can express dependencies on beans in the root application context via simple bean references. Therefore, typical Spring web MVC applications never need to perform a manual lookup of an application context or bean factory, or do any other form of lookup.Neither do other client objects that are managed by an application context themselves: They can receive collaborating objects as bean references.The Core Bean FactoryIn the previous section, we have seen a typical usage of the Spring IoC container in a web environment: The provided convenience classes allow for seamless integration without having to worry about low-level container details. Nevertheless, it does help to look at the inner workings to understand how Spring manages the container. Therefore, we will now look at the Spring bean container in more detail, starting at the lowest building block: the bean factory. Later, we’ll continue with resource setup and details on the application context concept.One of the main incentives for a lightweight container is to dispense with the multitude of custom facto-ries and singletons often found in J2EE applications. The Spring bean factory provides one consistent way to set up any number of application objects, whether coarse-grained components or fine-grained busi-ness objects. Applying reflection and Dependency Injection, the bean factory can host components that do not need to be aware of Spring at all. Hence we call Spring a non-invasiveapplication framework.Fundamental InterfacesThe fundamental lightweight container interface isorg.springframework.beans.factory.Bean Factory. This is a simple interface, which is easy to implement directly in the unlikely case that none of the implementations provided with Spring suffices. The BeanFactory interface offers two getBean() methods for looking up bean instances by String name, with the option to check for a required type (and throw an exception if there is a type mismatch).public interface BeanFactory {Object getBean(String name) throws BeansException;Object getBean(String name, Class requiredType) throws BeansException;boolean containsBean(String name);boolean isSingleton(String name) throws NoSuchBeanDefinitionException;String[] getAliases(String name) throws NoSuchBeanDefinitionException;}The isSingleton() method allows calling code to check whether the specified name represents a sin-gleton or prototype bean definition. In the case of a singleton bean, all calls to the getBean() method will return the same object instance. In the case of a prototype bean, each call to getBean() returns an inde-pendent object instance, configured identically.The getAliases() method will return alias names defined for the given bean name, if any. This mecha-nism is used to provide more descriptive alternative names for beans than are permitted in certain bean factory storage representations, such as XML id attributes.The methods in most BeanFactory implementations are aware of a hierarchy that the implementation may be part of. If a bean is not found in the current factory, the parent factory will be asked, up until the root factory. From the point of view of a caller, all factories in such a hierarchy will appear to be merged into one. Bean definitions in ancestor contexts are visible to descendant contexts, but not the reverse.All exceptions thrown by the BeanFactory interface and sub-interfaces extend org.springframework. beans.BeansException, and are unchecked. This reflects the fact that low-level configuration prob-lems are not usually recoverable: Hence, application developers can choose to write code to recover from such failures if they wish to, but should not be forced to write code in the majority of cases where config-uration failure is fatal.Most implementations of the BeanFactory interface do not merely provide a registry of objects by name; they provide rich support for configuring those objects using IoC. For example, they manage dependen-cies between managed objects, as well as simple properties. In the next section, we’ll look at how such configuration can be expressed in a simple and intuitive XML structure.The sub-interface org.springframework.beans.factory.ListableBeanFactory supports listing beans in a factory. It provides methods to retrieve the number of beans defined, the names of all beans, and the names of beans that are instances of a given type:public interface ListableBeanFactory extends BeanFactory {int getBeanDefinitionCount();String[] getBeanDefinitionNames();String[] getBeanDefinitionNames(Class type);boolean containsBeanDefinition(String name);Map getBeansOfType(Class type, boolean includePrototypes,boolean includeFactoryBeans) throws BeansException}The ability to obtain such information about the objects managed by a ListableBeanFactory can be used to implement objects that work with a set of other objects known only at runtime.In contrast to the BeanFactory interface, the methods in ListableBeanFactory apply to the current factory instance and do not take account of a hierarchy that the factory may be part of. The org.spring framework.beans.factory.BeanFactoryUtils class provides analogous methods that traverse an entire factory hierarchy.There are various ways to leverage a Spring bean factory, ranging from simple bean configuration to J2EE resource integration and AOP proxy generation. The bean factory is the central, consistent way of setting up any kind of application objects in Spring, whether DAOs, business objects, or web controllers. Note that application objects seldom need to work with the BeanFactory interface directly, but are usu-ally configured and wired by a factory without the need for any Spring-specific code.For standalone usage, the Spring distribution provides a tiny spring-core.jar file that can be embed-ded in any kind of application. Its only third-party dependency beyond J2SE 1.3 (plus JAXP for XML parsing) is the Jakarta Commons Logging API.The bean factory is the core of Spring and the foundation for many other services that the framework offers. Nevertheless, the bean factory can easily be usedstan-dalone if no other Spring services are required.附录2 中文译文Spring框架介绍Spring框架:这是一个流行的开源应用框架,它可以解决很多问题。
MVC设计模式THE-MVC-WEB-DESIGN-PATTERN大学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:MVC设计模式文献、资料英文题目:THE MVC-WEB DESIGN PATTERN文献、资料来源:文献、资料发表(出版)日期:院(部):专业:班级:姓名:学号:指导教师:翻译日期: 2017.02.14MVC设计模式Ralph F. Grove计算机科学,詹姆斯麦迪逊大学,哈里森堡,美国弗吉尼亚州***************Eray Ozkan计算机科学,詹姆斯麦迪逊大学,哈里森堡,美国弗吉尼亚州*****************关键字:web,web框架,设计模式,模型-视图-控制器模式摘要:模型-视图-控制器模式被引用为许多web开发框架的基础架构。
然而,用于web开发的MVC 版本随着原来的Smalltalk的MVC的演变而发生了一些改变。
本文介绍了对这些变化的分析,并提出了一种独立的Web-MVC模式,用于更准确的描述MVC是如何在web框架中实现的。
1.介绍模型-视图-控制器(Modle-View-Controller,MVC)设计模式被一些web应用框架作为基础架构,例如,Rails,以及Struts。
MVC最初是在施乐帕克研究中心(Goldberg和Robson,1985)开发的Smalltalk编程环境中实现的。
为了适应web框架,MVC已经演变成了另一种方式,最终成为一种不同于其他任何设计模式,也与原始的Smaltalk完全不同的模式的实现。
本文的第一个目标是介绍MVC设计模式,其中包括它的原始形态(第2节)以及现代众所周知的用于web应用框架的变更后的形态(第3节)。
第二个目标是对这个模式演变后发生的变化进行评估,同时呈现演变后版本的有效性(第3节)。
最后,我们提出了一个标准的MVC-Web设计模式的描述,用于反映目前在web框架中模式的使用,同时又能保持原始的MVC中令人满意的特性。
基于MVC的web应用框架的修订版本已经被提出了(Chun, Yanhua, 和Hanhong, 2003) (Barrett和Delaney, 2004)。
英文论文(外文文献)翻译成中文的格式与方法

英文论文(外文文献)翻译成中文的格式与方法英文论文(外文文献)翻译成中文的格式与方法本文关键词:外文,英文,中文,翻译成,文献英文论文(外文文献)翻译成中文的格式与方法本文简介:在撰写毕业设计(论文)或科研论文时,需要参考一些相关外文文献,了解国外的最新研究进展,这就需要我们找到最新最具代表性的外文文献,进行翻译整理,以备论文写作时参考,外文文献中英文文献占绝大多数,因此英文论文准确的翻译成中文就显得尤为重要!一、外文文献从哪里下载1、从知网国际文献总库中找英文论文(外文文献)翻译成中文的格式与方法本文内容:在撰写毕业设计(论文)或科研论文时,需要参考一些相关外文文献,了解国外的最新研究进展,这就需要我们找到最新最具代表性的外文文献,进行翻译整理,以备论文写作时参考,外文文献中英文文献占绝大多数,因此英文论文准确的翻译成中文就显得尤为重要!一、外文文献从哪里下载1、从知网国际文献总库中找,该数据库中包含14,000多家国外出版社的文献,囊括所有专业的英文文献资料。
2、一些免费的外文数据库或网站,为了方便大家查找,编者整理成文档供大家下载:国外免费文献数据库大全下载3、谷歌学术检索工具,检索时设置成只检索英文文献,键入与专业相关的关键词即可检索。
二、英文论文翻译格式与要求翻译的外文文献的字符要求不少于1.5万(或翻译成中文后至少在3000字以上)。
字数达到的文献一篇即可。
翻译的外文文献应主要选自学术期刊、学术会议的文章、有关着作及其他相关材料,应与毕业论文(设计)主题相关,并作为外文参考文献列入毕业论文(设计)的参考文献。
并在每篇中文译文首页用"脚注"形式注明原文作者及出处,中文译文后应附外文原文。
需认真研读和查阅术语完成翻译,不得采用翻译软件翻译。
中文译文的编排结构与原文同,撰写格式参照毕业论文的格式要求。
参考文献不必翻译,直接使用原文的(字体,字号,标点符号等与毕业论文中的参考文献要求同),参考文献的序号应标注在译文中相应的地方。
建筑学Modern-Architecture现代建筑大学毕业论文外文文献翻译及原文

建筑学Modern-Architecture现代建筑⼤学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:现代建筑⽂献、资料英⽂题⽬:Modern Architecture⽂献、资料来源:⽂献、资料发表(出版)⽇期:院(部):专业:班级:姓名:学号:指导教师:翻译⽇期: 2017.02.14建筑学毕业设计的外⽂⽂献及译⽂⽂献、资料题⽬:《Advanced Encryption Standard》⽂献、资料发表(出版)⽇期:2004.10.25外⽂⽂献:Modern ArchitectureModern architecture, not to be confused with 'contemporary architecture', is a term given to a number of building styles with similar characteristics, primarily the simplification of form and the elimination of ornament. While the style was conceived early in the 20th century and heavily promoted by a few architects, architectural educators and exhibits, very few Modern buildings were built in the first half of the century. For three decades after the Second World War, however, it became the dominant architectural style for institutional and corporate building.1. OriginsSome historians see the evolution of Modern architecture as a social matter, closely tied to the project of Modernity and hence to the Enlightenment, a result of social and political revolutions.Others see Modern architecture as primarily driven by technological and engineering developments, and it is true that the availability of new building materials such as iron, steel, concrete and glass drove the invention of new building techniques as part of the Industrial Revolution. In 1796, Shrewsbury mill owner Charles Bage first used his ‘fireproof’ design, which relied on cast iron and brick with flag stone floors. Such construction greatly strengthened the structure of mills, which enabled them to accommodate much bigger machines. Due to poor knowledge of iron's properties as a construction material, a number of early mills collapsed. It was not until the early 1830s that Eaton Hodgkinson introduced the section beam, leading to widespread use of iron construction, this kind of austere industrial architecture utterly transformed the landscape of northern Britain, leading to the description, "Dark satanic mills" of places like Manchester and parts of West Yorkshire. The Crystal Palace by Joseph Paxton at the Great Exhibition of 1851 was an early example of iron and glass construction; possibly the best example is the development of the tall steel skyscraper in Chicago around 1890 by William Le Baron Jenney and Louis Sullivan. Early structures to employ concrete as the chief means of architectural expression (rather than for purely utilitarian structure) include Frank Lloyd Wright's Unity Temple, built in 1906 near Chicago, and Rudolf Steiner's Second Goetheanum, built from1926 near Basel, Switzerland.Other historians regard Modernism as a matter of taste, a reaction against eclecticism and the lavish stylistic excesses of Victorian Era and Edwardian Art Nouveau.Whatever the cause, around 1900 a number of architects around the world began developing new architectural solutions to integrate traditional precedents (Gothic, for instance) with new technological possibilities. The work of Louis Sullivan and Frank Lloyd Wright in Chicago, Victor Horta in Brussels, Antoni Gaudi in Barcelona, Otto Wagner in Vienna and Charles Rennie Mackintosh in Glasgow, among many others, can be seen as a common struggle between old and new.2. Modernism as Dominant StyleBy the 1920s the most important figures in Modern architecture had established their reputations. The big three are commonly recognized as Le Corbusier in France, and Ludwig Mies van der Rohe and Walter Gropius in Germany. Mies van der Rohe and Gropius were both directors of the Bauhaus, one of a number of European schools and associations concerned with reconciling craft tradition and industrial technology.Frank Lloyd Wright's career parallels and influences the work of the European modernists, particularly via the Wasmuth Portfolio, but he refused to be categorized with them. Wright was a major influence on both Gropius and van der Rohe, however, as well as on the whole of organic architecture.In 1932 came the important MOMA exhibition, the International Exhibition of Modern Architecture, curated by Philip Johnson. Johnson and collaborator Henry-Russell Hitchcock drew together many distinct threads and trends, identified them as stylistically similar and having a common purpose, and consolidated them into the International Style.This was an important turning point. With World War II the important figures of the Bauhaus fled to the United States, to Chicago, to the Harvard Graduate School of Design, and to Black Mountain College. While Modern architectural design never became a dominant style in single-dwelling residential buildings, in institutional and commercial architecture Modernism became the pre-eminent, and in the schools (for leaders of the profession) the only acceptable, design solution from about 1932 to about 1984.Architects who worked in the international style wanted to break with architectural tradition and design simple, unornamented buildings. The most commonly used materials are glass for the facade, steel for exterior support, and concrete for the floors and interior supports; floor plans were functional and logical. The style became most evident in the design of skyscrapers. Perhaps its most famous manifestations include the United Nations headquarters (Le Corbusier, Oscar Niemeyer, Sir Howard Robertson), the Seagram Building (Ludwig Mies van der Rohe), and Lever House (Skidmore, Owings, and Merrill), all in New York. A prominent residential example is the Lovell House (Richard Neutra) in Los Angeles.Detractors of the international style claim that its stark, uncompromisingly rectangular geometry is dehumanising. Le Corbusier once described buildings as "machines for living", but people are not machines and it was suggested that they do not want to live in machines. Even Philip Johnson admitted he was "bored with the box." Since the early 1980s many architects have deliberately sought to move away from rectilinear designs, towards more eclectic styles. During the middle of the century, some architects began experimenting in organic forms that they felt were more human and accessible. Mid-century modernism, or organic modernism, was very popular, due to its democratic and playful nature. Alvar Aalto and Eero Saarinen were two of the most prolific architects and designers in this movement, which has influenced contemporary modernism.Although there is debate as to when and why the decline of the modern movement occurred, criticism of Modern architecture began in the 1960s on the grounds that it was universal, sterile, elitist and lacked meaning. Its approach had become ossified in a "style" that threatened to degenerate into a set of mannerisms. Siegfried Giedion in the 1961 introduction to his evolving text, Space, Time and Architecture (first written in 1941), could begin "At the moment a certain confusion exists in contemporary architecture, as in painting; a kind of pause, even a kind of exhaustion." At the Metropolitan Museum of Art, a 1961 symposium discussed the question "Modern Architecture: Death or Metamorphosis?" In New York, the coup d'état appeared to materialize in controversy around the Pan Am Building that loomed over Grand Central Station, taking advantage of the modernist real estate concept of "air rights",[1] In criticism by Ada Louise Huxtable and Douglas Haskell it was seen to "sever" the Park Avenue streetscape and "tarnish" the reputations of its consortium of architects: Walter Gropius, Pietro Belluschi and thebuilders Emery Roth & Sons. The rise of postmodernism was attributed to disenchantment with Modern architecture. By the 1980s, postmodern architecture appeared triumphant over modernism, including the temple of the Light of the World, a futuristic design for its time Guadalajara Jalisco La Luz del Mundo Sede International; however, postmodern aesthetics lacked traction and by the mid-1990s, a neo-modern (or hypermodern) architecture had once again established international pre-eminence. As part of this revival, much of the criticism of the modernists has been revisited, refuted, and re-evaluated; and a modernistic idiom once again dominates in institutional and commercial contemporary practice, but must now compete with the revival of traditional architectural design in commercial and institutional architecture; residential design continues to be dominated by a traditional aesthetic.中⽂译⽂:现代建筑现代建筑,不被混淆与'当代建筑' , 是⼀个词给了⼀些建筑风格有类似的特点, 主要的简化形式,消除装饰等. 虽然风格的设想早在20世纪,并⼤量造就了⼀些建筑师、建筑教育家和展品,很少有现代的建筑物,建于20世纪上半叶. 第⼆次⼤战后的三⼗年, 但最终却成为主导建筑风格的机构和公司建设.1起源⼀些历史学家认为进化的现代建筑作为⼀个社会问题, 息息相关的⼯程中的现代性,从⽽影响了启蒙运动,导致社会和政治⾰命.另⼀些⼈认为现代建筑主要是靠技术和⼯程学的发展, 那就是获得新的建筑材料,如钢铁, 混凝⼟和玻璃驱车发明新的建筑技术,它作为⼯业⾰命的⼀部分. 1796年, shrewsbury查尔斯bage⾸先⽤他的'⽕'的设计, 后者则依靠铸铁及砖与⽯材地板. 这些建设⼤⼤加强了结构,使它们能够容纳更⼤的机器. 由于作为建筑材料特性知识缺乏,⼀些早期建筑失败. 直到1830年初,伊顿Hodgkinson预计推出了型钢梁, 导致⼴泛使⽤钢架建设,⼯业结构完全改变了这种窘迫的⾯貌,英国北部领导的描述, "⿊暗魔⿁作坊"的地⽅如曼彻斯特和西约克郡. ⽔晶宫由约瑟夫paxton的重⼤展览, 1851年,是⼀个早期的例⼦,钢铁及玻璃施⼯; 可能是⼀个最好的例⼦,就是1890年由William乐男爵延长和路易沙利⽂在芝加哥附近发展的⾼层钢结构摩天楼. 早期结构采⽤混凝⼟作为⾏政⼿段的建筑表达(⽽⾮纯粹功利结构) ,包括建于1906年在芝加哥附近,劳埃德赖特的统⼀宫, 建于1926年瑞⼠巴塞尔附近的鲁道夫斯坦纳的第⼆哥特堂,.但⽆论原因为何, 约有1900多位建筑师,在世界各地开始制定新的建筑⽅法,将传统的先例(⽐如哥特式)与新的技术相结合的可能性.路易沙利⽂和赖特在芝加哥⼯作,维克多奥尔塔在布鲁塞尔,安东尼⾼迪在巴塞罗那, 奥托⽡格纳和查尔斯景mackintosh格拉斯哥在维也纳,其中之⼀可以看作是⼀个新与旧的共同⽃争.2现代主义风格由1920年代的最重要⼈物,在现代建筑⾥确⽴了⾃⼰的名声. 三个是公认的柯布西耶在法国, 密斯范德尔德罗和⽡尔特格罗⽪乌斯在德国. 密斯范德尔德罗和格罗⽪乌斯为董事的包豪斯, 其中欧洲有不少学校和有关团体学习调和⼯艺和传统⼯业技术.赖特的建筑⽣涯中,也影响了欧洲建筑的现代艺术,特别是通过⽡斯穆特组合但他拒绝被归类与他们. 赖特与格罗⽪乌斯和Van der德罗对整个有机体系有重⼤的影响.在1932年来到的重要moma展览,是现代建筑艺术的国际展览,艺术家菲利普约翰逊. 约翰逊和合作者亨利-罗素阁纠集许多鲜明的线索和趋势, 内容相似,有⼀个共同的⽬的,巩固了他们融⼊国际化风格这是⼀个重要的转折点. 在⼆战的时间包豪斯的代表⼈物逃到美国,芝加哥,到哈佛⼤学设计⿊⼭书院. 当现代建筑设计从未成为主导风格单⼀的住宅楼,在成为现代卓越的体制和商业建筑, 是学校(专业领导)的唯⼀可接受的, 设计解决⽅案,从约1932年⾄约1984年.那些从事国际风格的建筑师想要打破传统建筑和简单的没有装饰的建筑物。
本科毕业设计外文文献翻译

(Shear wall st ructural design ofh igh-lev el fr ameworkWu Jiche ngAbstract : In t his pape r the basic c oncepts of man pow er from th e fra me sh ear w all str uc ture, analy sis of the struct ur al des ign of th e c ont ent of t he fr ame she ar wall, in cludi ng the seism ic wa ll she ar spa本科毕业设计外文文献翻译学校代码: 10128学 号:题 目:Shear wall structural design of high-level framework 学生姓名: 学 院:土木工程学院 系 别:建筑工程系 专 业:土木工程专业(建筑工程方向) 班 级:土木08-(5)班 指导教师: (副教授)nratiodesign, and a concretestructure in themost co mmonly usedframe shear wallstructurethedesign of p oints to note.Keywords: concrete; frameshearwall structure;high-risebuildingsThe wall is amodern high-rise buildings is an impo rtant buildingcontent, the size of theframe shear wall must comply with building regulations. The principle is that the largersizebut the thicknessmust besmaller geometric featuresshouldbe presented to the plate,the force is close to cylindrical.The wall shear wa ll structure is a flatcomponent. Itsexposure to the force along the plane level of therole ofshear and moment, must also take intoaccountthe vertical pressure.Operate under thecombined action ofbending moments and axial force andshear forcebythe cantilever deep beam under the action of the force levelto loo kinto the bottom mounted on the basis of. Shearwall isdividedinto a whole walland theassociated shear wall in theactual project,a wholewallfor exampl e, such as generalhousingconstruction in the gableor fish bone structure filmwalls and small openingswall.Coupled Shear walls are connected bythecoupling beam shear wall.Butbecause thegeneralcoupling beamstiffness is less thanthe wall stiffnessof the limbs,so. Walllimb aloneis obvious.The central beam of theinflection pointtopay attentionto thewall pressure than the limits of the limb axis. Will forma shortwide beams,widecolumn wall limbshear wall openings toolarge component atbothen ds with just the domain of variable cross-section ro din the internalforcesunder theactionof many Walllimb inflection point Therefore, the calcula tions and construction shouldAccordingtoapproximate the framestructure to consider.The designof shear walls shouldbe based on the characteristics of avariety ofwall itself,and differentmechanical ch aracteristicsand requirements,wall oftheinternalforcedistribution and failuremodes of specific and comprehensive consideration of the design reinforcement and structural measures. Frame shear wall structure design is to consider the structure of the overall analysis for both directionsofthehorizontal and verticaleffects. Obtain theinternal force is required in accordancewiththe bias or partial pull normal section forcecalculation.The wall structure oftheframe shear wall structural design of the content frame high-rise buildings, in the actual projectintheuse of themost seismic walls have sufficient quantitiesto meet thelimitsof the layer displacement, the location isrelatively flexible. Seismic wall for continuous layout,full-length through.Should bedesigned to avoid the wall mutations in limb length and alignment is notupand down the hole. The sametime.The inside of the hole marginscolumnshould not belessthan300mm inordertoguaranteethelengthof the column as the edgeof the component and constraint edgecomponents.Thebi-direc tional lateral force resisting structural form of vertical andhorizontalwallconnected.Each other as the affinityof the shear wall. For one, two seismic frame she ar walls,even beam highratio should notgreaterthan 5 and a height of not less than400mm.Midline columnand beams,wall midline shouldnotbe greater tha nthe columnwidthof1/4,in order toreduce thetorsional effect of the seismicaction onthecolumn.Otherwisecan be taken tostrengthen thestirrupratio inthe column tomake up.If theshear wall shearspan thanthe big two. Eventhe beamcro ss-height ratiogreaterthan 2.5, then the design pressure of thecut shouldnotmakeabig 0.2. However, if the shearwallshear spanratioof less than two couplingbeams span of less than 2.5, then the shear compres sion ratiois notgreater than 0.15. Theother hand,the bottom ofthe frame shear wallstructure to enhance thedesign should notbe less than200mmand notlessthanstorey 1/16,otherpartsshouldnot be less than 160mm and not less thanstorey 1/20. Aroundthe wall of the frame shear wall structure shouldbe set to the beam or dark beamand the side columntoform a border. Horizontal distributionofshear walls can from the shear effect,this design when building higher longeror framestructure reinforcement should be appropriatelyincreased, especially in the sensitiveparts of the beam position or temperature, stiffnesschange is bestappropriately increased, thenconsideration shouldbe givento the wallverticalreinforcement,because it is mainly from the bending effect, andtake in some multi-storeyshearwall structurereinforcedreinforcement rate -likelessconstrained edgeofthecomponent or components reinforcement of theedge component.References: [1 sad Hayashi,He Yaming. On the shortshear wall high-rise buildingdesign [J].Keyuan, 2008, (O2).高层框架剪力墙结构设计吴继成摘要: 本文从框架剪力墙结构设计的基本概念人手, 分析了框架剪力墙的构造设计内容, 包括抗震墙、剪跨比等的设计, 并出混凝土结构中最常用的框架剪力墙结构设计的注意要点。
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附录1:外文原文外文翻译附录2:外文翻译钢筋混凝土建筑在地震中的抗倒塌安全性研究(二):延性和非延性框架的对比分析(Abbie B. Liel1, Curt B. Haselton2, and Gregory G. Deierlein3)摘要:本文是两篇配套论文的第二篇,旨在探讨钢筋混凝土框架结构在地震中的抗倒塌安全性,并检验加利福尼亚州在20世纪70年代中期之前所建非延性框架结构建筑的可靠性。
基于对结构响应的非线性动态模拟进行概率评估,以此来计算对应于不同的地运动特性和结构类型时结构倒塌的危险。
评估的对象是一套不同高度的非延性钢筋混凝土框架结构原型,它们是根据1967年版《统一建筑规范》中的抗震规定设计的。
结果表明,当处于一个典型的加利福尼亚高震场地时,非延性钢筋混凝土框架结构发生倒塌的年平均频率范围为(5~14)×10-3,这比按现代规范设计的结果高出约40倍。
这些数据表明新规范对延性构造和能力设计要求是行之有效的,这使得在过去的30年中新建的钢筋混凝土建筑物的安全性得到明显改善。
通过对延性和非延性结构的安全性比较,有助于出台新的规章来评估和减轻现有的钢筋混凝土框架结构建筑物地震倒塌的危险。
关键词:倒塌;地震工程;结构可靠度;钢筋混凝土结构;建筑;商业;地震影响。
引言20世纪70年代中期以前加利福尼亚州建设的钢筋混凝土框架结构缺乏好的抗震设计理念(例如:加强柱子、钢筋延性构造),这使得它们很容易在地震中发生倒塌。
这些非延性钢筋混凝土框架结构在经历了加利福尼亚州1971年圣费尔南多大地震,1979年英皮里尔谷大地震,1987年惠蒂尔纳罗斯大地震,1994年北山大地震和世界上其他地方发生的无数地震之后,已经遭受了很严重的地震损害。
这些因素促使人们关注加利福尼亚州的近40000栋钢筋混凝土建筑,其中的一部分在未来地震中可能会发生倒塌而危害生命财产安全。
然而,我们缺乏足够的数据来衡量建筑的危险程度,因而无法确定是大量的建筑均存在这种危险,还是只有特定的建筑物才存在危险。
一栋建筑物发生倒塌的危险大小,不仅取决于其原设计采用的建筑规范中的规定,也取决于结构布置、施工质量、建筑位置和场地的地震特性。
除了需要准确评估倒塌的风险之外,选择合适的危险承受值和最低的安全标准也是需要考虑的问题。
在这方面,通过比较评估根据新老建筑规范设计出的建筑物,能帮我们找到一种评估手段来确定目前设计能够接受的风险水平。
20世纪70年代中期以来,随着对地震破坏和钢筋延性的深入了解,建筑规范中对于钢筋混凝土抗震设计和构造措施的要求发生了显著变化。
同老式非延性钢筋混凝土框架结构相比,现代规范要求在高地震地区的框架结构要进行各种能力设计来防止或延缓不利的破坏形式(如柱剪切破坏,梁柱节点破坏)。
虽然人们普遍同意对于建筑规范的这些修改是适当的,但还是缺少足够的数据以量化其对地震安全性的改善程度。
这项研究采用基于性能的地震工程方法,以评估地震引起非延性钢筋混凝土框架结构倒塌的可能性。
基于性能的地震工程提供了一个概率框架,利用非线性时程模拟将地面运动强度与结构响应和建筑性能联系起来。
对非延性钢筋混凝土框架结构的评估基于原型结构所做的测试,这套结构是根据1967年《统一建筑规范》设计的。
这些原型结构代表了1950年至1975年间在加州建造的普通钢筋混凝土框架结构。
通过对非延性混凝土框架结构原型的非线性动态分析可以预测倒塌的发生,而在结构倒塌过程中利用仿真模型能够捕获强度和刚度的变化特征。
抗倒塌性能评估的成果是一系列保障建筑安全的措施,并将地震中抗倒塌能力与地震灾害联系到一起。
我们将这些结果与另一篇配套论文中的关于延性钢筋混凝土框架结构的数据进行比较。
原型钢筋混凝土框架结构这些非延性钢筋混凝土框架结构原型考虑了结构高度的变化,结构布置和细部设计,能够覆盖加州旧钢筋混凝土框架结构建筑物设计和性能的的预期范围。
制作原型时,我们查阅了钢筋混凝土部件和框架的关键参数,这些参数是由哈兹尔顿等人通过分析和实验获得的。
本项研究共制作了26个非延性钢筋混凝土框架原型建筑物。
本文主要侧重于这些设计中的12个,高度从2层到12层变化,并包括具有可替换设计细节的周边和空间框架侧向抵抗系统。
原型建筑均设计为有着20厘米平面楼板系统和7.6米柱间距的办公楼房。
2层和4层建筑的平面尺寸为38.1m×53.3m,8层和12层建筑的平面尺寸为38.1m×38.1m。
建筑首层层高4.6m,其余层层高4.0m。
我们参考了20世纪60年代在加州建设的钢混建筑的原结构图,来为原型结构选择典型的结构部置和几何形状。
原型仅限于无填充墙的钢筋混凝土框架,并且在高度和平面上比较规则,没有出现明显的强度或刚度突变。
非延性钢混原型结构是按照1967年《统一建筑规范》中的最高地震烈度区(3区)设计的,那个时代加州的大部分都属于这个烈度区。
二维框架的结构设计是由所需的强度和刚度控制的,应满足重力和地震荷载组合的要求。
设计也符合所有相关的建筑规范要求,包括最大和最小配筋率和最大箍筋间距。
1967年《统一建筑规范》规定,如果采用了延性构造措施,可以适当地减小基底剪应力。
然而,本研究并没有进行这种折减,只考虑标准的细部构造。
表1总结了每个结构的设计细节,在Liel 和Deierlein处可以获得非延性钢混原型的完整资料。
有4个4层和12层的原型做了细部加强,这会在随后的文章里作介绍。
我们将非延性原型钢混框架结构的抗倒塌性能与配套论文中的延性原型钢混结构做了对比。
如表2总结,这些延性框架的设计依据了《国际建筑规范》(ICC 2003)、ASCE 7 (ASCE 2002),、和 ACI 318 (ACI 2005)中的规定,并符合所有相关规范中关于强度,刚度,承载能力和特殊框架构造的要求。
这些结构得益于自20世纪70年代以来钢筋混凝土抗震设计规范不断增加的条款,包括各种关于能力设计的规定(例如:强柱弱梁,节点抗剪承载力设计)和构造措施的改进(例如,在梁柱塑性铰区增加横向约束,提高对搭接的要求,闭合箍筋)。
这套延性钢混框架是按照在土壤类型为Sd类的典型高震洛杉矶场地设计的,它处在2003版IBC设计地图的过渡区域。
表1 原型延性和非延性框架的设计属性附注:a)1967年《统一建筑规范》(UBC)中设计基底剪切系数取值为C=0.05/T(1/3)≤0.10。
对于抵抗力矩的框架T=0.1N,N是层数(ICBO 1967);b)现代建筑的设计基底系数根据设计场地的反应谱取值。
洛杉矶场地的设计反应谱SDS=1.0g,SD1=0.60g。
计算式采用的周期根据规范公式算得,是结构的高度(英尺),并且规定了计算周期的上限()(ASCE 2002);c)柱子的属性沿结构高度变化,此处列出的是首层柱子的属性;d)各构件横向钢筋的配置由所需的剪切强度确定。
每个位置至少有两根3号钢筋;e)延性钢筋混凝土框架横向钢筋的配置由所需的剪切强度确定。
所有的弯锚都有抗震构造,并使用4号钢筋(ACI 2005);f)梁属性沿结构的高度变化,此处列出的是第二层梁的属性;g)所设计结构的梁柱构造优于平均水平;h)所设计结构的节点构造由于平均水平。
表2 原型延性和非延性框架的建模参数附注:a)此处列出的是首层柱的参数;b)轴向荷载包括恒荷载和25%的活荷载;c)有效割线刚度为通过40%屈服强度时的割线刚度;d)滞后能量耗散的计算公式为;e)参数获得于对结构模型的特征值分析;f)所设计结构梁柱的构造优于平均水平;g)所设计结构的节点构造优于平均水平。
对比表1所示的结构,我们可以看出在过去四十年间钢筋混凝土框架抗震设计规范的变化。
尽管对设计基底剪力的方程进行了修改,但对于相同高度的延性和非延性钢混框架结构,计算的结果还是相当接近的,只有在计算最矮的结构时才有较大的偏差。
两组建筑物之间明显的差别是部件的设计和构造措施,特别是在数量、布局、和横向加固方面。
现代钢混框架结构受剪切能力设计规定的影响,对于箍筋间距有着更严格的限制,例如:在延性钢筋混凝土梁和柱中横向钢筋要加密2到4倍。
最小配箍率保证了柱子有足够的强度来延缓楼层机构的形成。
因此,在节点处柱强度与梁强度的比值延性钢筋混凝土框架结构平均比非延性钢筋混凝土框架结构高出约30%。
非延性钢混框架结构对于梁柱节点区域的设计或加固也没有特别规定,而延性钢混框架结构的柱子则要求规定的尺寸并添加横向钢筋,以满足节点剪力的需要。
为满足特殊框架结构对节点剪切强度的要求,通常增加柱子的尺寸,从而减小轴压比。
非线性仿真模型每个原型非延性钢混框架的非线性分析模型,都包括一个二维三开间的侧向抗力系统,如图1所示。
分析模型能够体现柱子、梁、梁柱节点材料的非线性和大尺寸效应(P-Δ效应),这对于模拟框架的倒塌时十分重要的。
我们用端部部分铰接的构件模拟梁、柱及其节点,这些铰被部分约束以模拟真实情况,类似于弹簧铰。
结构模型不包括任何非结构构件或支撑重力荷载的部件,它们都不属于横向支撑系统。
本模型是在OpenSees中建造的,该软件具有强大的计算功能。
图 1. 钢筋混凝土框架结构分析模型示意图在另一篇配套论文中,用集中弹簧模拟非弹性的梁、柱、节点,它们是根据三线图和伊瓦拉等人的滞后原则理想化而来的。
根据一系列经验关系,我们对代表梁和柱构件的非线性弹簧特性进行了预测,这些关系将柱子的设计特征同建模参数联系起来,并与实验数据进行了校核。
用于改进经验关系的试验,包括大量非延性构造的钢筋混凝土柱。
预测的模型参数反映非延性和延性钢筋混凝土构件的弯矩-转角行为的差异。
正如配套论文中所说的,由于缺少足够的梁的数据,对于钢筋混凝土梁的模型参数的校核是建立在柱子在低轴压水平下被测试的基础上的。
图2(a)显示了延性及非延性柱(均为4层建筑)的单调骨干曲线的性质。
众所周知,最大塑性转角θcap,pl对预测倒塌的发生有重要影响,它是柱子约束钢筋和轴压水平的函数,延性钢筋混凝土柱比非延性钢筋混凝土柱大约大2.7倍。
延性钢筋混凝土柱还有更强的后期旋转能力(θpc),这决定了的柱子屈服后强度退化的速度。
图2(b)表明在一个典型的地震加载过程中,柱的强度和刚度不断下降。
起始曲线的减弱过程由弱化参数λ控制,这是一个耗能的过程。
在非延性柱中由于缺少足够的约束,并且轴压荷载更大,其耗能的能力要比延性柱小很多。
模型参数需要校准到预期的水平。
在分析时需计入重力荷载,并忽略轴向、弯曲、剪切变形之间的相互作用,而这些因素对高层建筑物的影响是十分明显的。
图 2. 用非弹性弹簧模拟位于4层框架结构首层中的钢筋混凝土柱,其特点是:(a)单调;(b)循环。
表2中为非延性和延性的原型钢筋混凝土柱的建模参数。