土木专业英语课件lesson2.doc

Lesson 2 Introduction to structural designNew words1. framework frame+work=frame 构架，框架; frame structure, 框架结构2. constraintvt. constrain 约束，强迫；n. constraint 约束 3. collaborate vt. 合作，通敌；collaboration, collaborative 4. evaluation vt. evaluate, value; assess, assessment5. fixturevt. fix, fixture 固定设备，固定物，夹具6. partition vt. n 分割，划分， make apart; partition wall7. overlook8. cranen. 超重机，鹤9. fatigue vt.vi.n 疲劳 fatigue strength, fatigue failure10. driftv.n 漂流，漂移，雪堆11. enumerate v. list 列举12. plumbingn. (卫生，自来水)管道，plumber 管道工13. ventilation n. 通风， ventilate, ventilate a room, a well-ventilated room, vent 通风口14. accessibility n. 可达性， access, n. vt. 通道，接近；accessible 易接近的，可达到的 15. coden. vt 代码，编码，规范16. administer v. 管理，执行；administrate, 管理 17. metropolitan a. 大城市，of metropolis 18. consolidatev. 巩固，strengthen，reinforce; consolidation19. prescriptionn. 规定，命令，药方；prescribe 20. municipalityn. 市政当局，直辖市， municipal government21. specification n. 详述，规格, 规范；specify 22. mandaten. 书面命令，委托，Phrases and expressions 1. functional design功能设计2. bending moment弯矩3. dead load4. live load5. nonstructural components非结构构件6. force due to gravity7. gravity load8. building code9. design specifications 设计规程10. nonprofit organization非赢利组织，弄non-government organization 11. the National Building Code12. the Uniform Building Code13. the Standard Building Code14. Building Officials and Code Administrators International (BOCA) 国际建筑公务员与法规管理人员联合会15. AISC美国钢结构学会 American Institute of Steel Construction 16. AASHTO 美国公路和运输工作者协会American Association of State Highway and Transportation Officials17. AREA美国铁道工程协会the American Railway Engineering Association 18. AISI美国钢铁学会American Iron and Steel InstituteIntroduction to Structural DesignStructural design The structural design of building, whether of structural steel or reinforced concrete, requires the determination of the overall proportions and dimensions of the supporting framework and the selection of the cross sections of individual members. 建筑结构设计，不论是钢结构还是钢筋混凝土结构，都需要确定其支承结构的整体比例和尺寸以及各构件的截面尺寸。In most cases the functional design, including the establishment of the number of stories and the floor plan, will have been done by an architect, and the structural engineer must work within the constraints imposed by this design. 在大多数情况下，功能设计，包括楼层层数和楼层平面的确定，将要由建筑师来完成，因而结构工程师必须在此约束条件下工作。Ideally, the engineer and architect will collaborate throughout the design process so that the project is completed in an efficient manner. 在理想状态下，工程师和建筑师将在整个设计过程中协同工作从而高效地完成设计工作。In effect, however, the design can be summed up as follows: 然而，事实上，设计过程可概括如下：The architect decides how the building should look; the engineer must make sure that it doesnt fall down. 建筑师确定建筑物的外观，工程师必须确保其不会倒塌。Although this is an oversimplification, it affirms the first priority of the structural engineer: safety. Other important considerations include serviceability (how well the structure performs in terms of appearance and deflection) and economy. 尽管这样说过分简单，但它明确了工程师的第一个主要任务，即，确保安全。其它要考虑的因素包括适用性（就外观和挠曲而言其工作性能如何）。An economical structure requires an efficient use of materials and construction labor. Although this can usually be accomplished by a design that requires a minimum amount of material, savings can often be realized by using slightly more material if it results in a simpler, more easily constructed projects. 经济的结构要求对材料和人工的有效使用，尽管这通常都能通过要求最少材料来取得，但通过采用稍多的材料，但能使建筑物更简单和更容易建造常常会实现节约的目的。LoadsThe forces the act on a structure are called loads. They belong to one of two broad categories, dead load and live load. 作用在结构物上的各种力称为荷载，它们属于一两种广义类型，恒载和活载。Dead loads are those that are permanent, including the weight of the structure itself, which is sometimes called the self-weight. 恒载是那些永久荷载，包括结构自身的重量，有时也称为自重。Other dead loads in a building include the weight of nonstructural components such as floor coverings, suspended ceilings with light fixtures, and partitions. 其它建筑物恒载包括非结构构件的重量，如楼面面层、带有灯具的吊顶以及隔墙。All of the loads mentioned thus far are forces due to gravity and are referred to as gravity loads. 至此所提的各种荷载都是由重力所引起，因而称为重力荷载。Live loads, which can also be gravity loads, are those that are not as permanent as dead loads. 活载也可以是重力荷载，它们是那些不如恒载那样永久的荷载。This type may or may not be acting on the structure as any given time, and the location may not be fixed. 这类荷载可能也可能不总是作用在结构物上，且作用位置也可能不是固定的。Examples of live load include furniture, equipment, and occupants of buildings. 活荷载包括家具、设置和建筑物的居住者。In general, the magnitude of a live load is not as well defined as that of a dead load, and it usually must be estimated. In many cases, a given structural member must be investigated for various positions of the live load so that a potential failure situation is not overlooked. 通常，活荷载的大小不如恒载那样确定，常常必须估计。在许多情况下，必须研究活荷载作用在一给定的结构构件的各个位置以便不会漏掉每个可能的破坏情形。Building codesBuilding must be designed and constructed according to the provisions of a building codes, which is a legal document containing requirements related to such things as structural safety, fire safety, plumbing, ventilation, and accessibility to the physically disabled. 建筑物必须根据各种建筑规范的条款设计和建造，规范是一种法律文件，包含各种要求，如建筑安全、防火安全、上下水、通风和体残人的可达性等。A building code has the force of law and is administered by a governmental entity such as a city, a county, or, for some large metropolitan areas, a consolidated government. 建筑规范具有法律效力，由政府部位发布，如城市、县、对于大的城区，如联合政府。Building codes do not give design provisions, but they do specify the design requirements and constraints that must be satisfied. 建筑规范并不给出设计规定，但却规定设计必须满足的各种要求和约束条款。Of particular importance to the structural engineer is the prescription of minimum live loads for buildings. 对结构工程师特别重要的是建筑物的最小活荷载规定。Although the engineer is encouraged to investigate the actual loading conditions and attempt to determine realistic values, the structure must be able to support these specified minimum loads. 尽管鼓励工程师研究实际荷载工况以确定真实的荷载值，结构必须能支承这些规定的最小荷载。Design specificationsIn contrast to building codes, design specifications give more specific guidance for the design of structural members and their connections. 与建筑规范不同，设计规程给出结构构件及其连接的更具体的指南。They present the guidelines and criteria that enable a structural engineer to achieve the objectives mandated by a building code. 它们给出各种方针和标准，使结构工程师能建筑规范所规定的目标。Design specifications represent what is considered to be good engineering practice based on their latest research. 根据其最新研究，设计规程结出认为是好的工程作法。They are periodically revised and updated by supplements or by completely new editions. 它们通过补充或通过发布新版本得到定期修订和更新。As with model building codes, design specifications are written in a legal format by nonprofit organizations. 如同一般建筑规范，设计规程由非赢利组织编写。They have no legal standing on their own, but by presenting design criteria and limits in the form of legal mandates and prohibitions, they can easily be adopted, by reference, as part of a building code. 尽管它们本身并无法律地位，但却以法令和禁令的形式给出设计准则和限制，以参考文献的形式，它们可容易地被录入，并作为建筑规范的一部分。