土木工程专业外文翻译--建筑物的结构.doc

外文原文 TextStructure of Buildings Reading Material AStructural Planning and design Reading Material BTypes of Loads and Types of Stress ContentsUNIT ONETextIntroduction to Mechanics of MaterialsReading Material A Shear CenterB Allowable Stress Design and Strength DesignUNIT TWOTextThe Tensile TestReading Material A Comparative Study of the Mechanical Properties of Ductile and Brittle Materials B Strength TheoriesUNIT THREETextApplication of Mechanics of Materials and Its Study MethodReading Material A StressB Method of SectionsUNIT FOURTextDescription of the Force and Displacement MethodReading Material A Types of BeamsB Methods of Joints and Sections for Analyzing a TrussUNIT FIVETextStructure of BuildingsReading Material A Structural Planning and DesignB Types of Loads and Types of StressUNIT SIXTextPurpose 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 SEVENTextProperties of Concrete and Reinforced ConcreteReading Material A Property of Structural SteelB Nature of Wood and MasonryUNIT EIGHTTextBuilding Code ()Reading Material A Building Code ()B Building Code ()UNIT NINETextEarly History of Cement and ConcreteReading Material A The Hydration ReactionB Distress and Failure of ConcreteUNIT TENTextAdvantages and Disadvantages of Concrete and Its Water-Cement RatioReading Material A Slump Test and Concrete ProportioningB Curing ConcreteUNIT ELEVENTextMortarReading Material A Water RetentivelyB Cement Mortar and Lime MortarUNIT TWELVETextGeneral Planning ConsiderationsReading Material A HousingB HouseUNIT THIRTEENTextFactory DesignReading Material A Modern Building ConstructionB BuildingUNIT FOURTEENTextFundamental Objective of Structural Dynamics AnalysisReading Material A Organization of the TextB Methods of DiscretizationUNIT FIFTEENTextContents of Theory of ElasticityReading Material A Basic Assumptions in Classical ElasticityB Members in a State of Two-Dimensional StressUNIT SIXTEENTextHistorical Development of Finite Element MethodReading Material A General Description of the Finite Element MethodB Introduction of Displacement ApproachAppendix VocabularyAppendix Translation for ReferenceAppendix Key to Exercises 目 录一、Foreign original UNIT FIVE1. Text Structure of Buildings··········································1-32. Reading Material AStructural Planning and design·················································································4-53. Reading Material BTypes of Loads and Types of Stress·················································································6-8Types of Loads································································6-7Types 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···········································113. 阅读材料 B 荷载类型及应力类型··································12-13负载类型············································································12 应力类型 ··········································································13UNIT FIVEText Structure of Buildings1 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: stability strength and stiffness economy5 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 provided so 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 systems for 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”。Beginning this study of forces and stresses and deformations is most easily done through quantitative methods. These two subjects form the basis for all structural planning and design and are very difficult to learn in the abstract.In most building design efforts, the initial structural planning is done by the architect. Ideally, the structural and mechanical consultants should work side by side with the architect from the conception of a project to the final days of construction. In most cases, however, the architect must make some initial assumptions about the relationships to be developed between the building form and the structural system. A solid background in structural principles and behavior is needed to make these assumptions with any reasonable degree of confidence. The shape of the structural envelope, the location of all major supporting elements, the directionality (if any) of the system, the selection of the major structural materials, and the preliminary determination of span lengths are all part of the structural planning process.Structural design, on the other hand, is done by both the architect and the engineer. The preliminary determination of the size of major structural elements, providing a check on the rationality of previous assumptions, is done by the architect and/or the engineer. Final structural design, involving a complete analysis of all the parts and components, the working out of structural details, and the specifying of structural materials and methods of construction is al- most always done by the structural engineer.Of the two areas, structural planning is far more complex than structural design. It involves the previously mentioned “feeling for structure” or intuition that comes through experience. Structural design can be learned from lectures and books, but it is likely that structural planning cannot. Nevertheless, some insight and judgment can be developed from a minimal background in structural analysis and design. If possible, this should be gained from an architectural standpoint, emphasizing the relationship between the quantities and the resulting qualities wherever possible, rather than from an engineering approach.This study of quantitative structures can be thorough enough to permit the architect to do completely the analysis for smaller projects, although such depth is not absolutely necessary. At the very least it should provide the knowledge and vocabulary necessary to work with the consulting engineer. It must be remembered that the architect receives much more education that is oriented toward creativity than does the engineer, and therefore needs to maintain control over the design. It is up to the architect to ask intelligent questions and suggest viable alternatives. If handicapped by structural ignorance, some of the design decisions will, in effect, be made by others.Reading Material BTypes of Loads and Types of StressTypes of LoadsIn general, loads that act on building structures can be divided into two groups; those due to gravitational attraction and those resulting from other natural causes and elements. Gravity loads can be further classified into two groups: live load and dead load. Building live loads include people and most movable objects within the structure or on top of it. Snow is a live load. So is a grand piano, a safe, or a water bed. Appendix O provides some typically recommended live loads for various types of occupancy within building structures. Research bears out that these figures represent probable maximum values for live loads during the lifetime of a structure. Such loads are seldom realized. What is more likely is an unexpected change in the use of the space. One can sense the problems that might result if an abandoned school is purchased for use as a warehouse (to store bowling balls). Dead loads, on the other hand, generally include the immovable objects in a building. The walls (both interior and exterior), floors, mechanical and electrical equipment, and the structural elements themselves are examples of dead loads.The snow map of Appendix N gives the maximum snow load that can reasonably be expected in various parts of the United States. Like the live-load values, such large snowfalls seldom occur. Nevertheless, we must design for some level of probability and should not forget such occurrences as the more than-500-millimeter snowfall that hit the southeastern United States in 1974, resulting in many small building failures. Natural forces not due to gravity that act on buildings are provided by wind and earth-quakes. Wind load is a lateral load that varies in intensity with height. (Hurricanes and tornadoes present special design problems, and local building codes often require certain types of resistive construction.) A probable wind pressure map is given in Appendix N. Earthquakes are also treated as lateral loads (at least for preliminary design purposes), but it is well known that buildings in earthquakes are subjected to vertical forces as well. De-sign methods are not fully developed for disaster loadings such as tornadoes and earthquakes, and research continues in these areas. One final type of load is an impact load, usually due to moving equipment, which occurs within or on the structure. Most structural materials can withstand a sudden and temporary load of higher magnitude than a load that is applied slowly. For this reason, the specified permissible stress magnitudes are substantially increased when such loads govern the design. No permanen