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1、<p> 2011 屆畢業(yè)設(shè)計(jì)專(zhuān)業(yè)外文翻譯</p><p> 題 目 Text Structure of Buildings</p><p> Reading Material A Structural Planning and design</p><p> Reading Material B Types of Loa
2、ds and Types of Stress</p><p> 專(zhuān) 業(yè) 土木工程 </p><p> 姓 名 王康建 </p><p> 班 級(jí) 07土Y4 </p><p> 學(xué) 號(hào) 0712462
3、0 </p><p> 指導(dǎo)教師 郭獻(xiàn)芳 李雄威 </p><p> 2011 年 1 月 16 日</p><p><b> Contents</b></p><p> UNIT ONEText Introduction to Mechanics of Mat
4、erialsReading Material A Shear Center B Allowable Stress Design and Strength DesignUNIT TWOText The Tensile TestReading Material A Comparative Study of the Mechanical Properties of Ductile and Brittle Materials
5、 B Strength TheoriesUNIT THREEText Application of Mechanics of Materials and Its Study MethodReading Material A Stress B Method of SectionsUNIT FOURText Description of the Force and Displacement MethodReading Mat
6、erial A Types </p><p><b> 目 錄</b></p><p> 一、Foreign original UNIT FIVE</p><p> Text Structure of Buildings·········
7、3;································1-3</p><p>
8、Reading Material A Structural Planning and design····························
9、83;····································&
10、#183;···············4-5</p><p> Reading Material B Types of Loads and Types of Stress·······
11、3;····································
12、183;····································
13、6-8</p><p> ⑴Types of Loads······························
14、;··································6-7</p>
15、<p> ?、芓ypes of stress ································
16、····························7-8</p><p> 二、外文譯文 第五單元</p><
17、;p> 課文 建筑物的結(jié)構(gòu)··································
18、;·························9-10</p><p> 閱讀材料 A 結(jié)構(gòu)的規(guī)劃和設(shè)計(jì)····
19、83;····································&
20、#183;·11</p><p> 閱讀材料 B 荷載類(lèi)型及應(yīng)力類(lèi)型····························
21、······12-13</p><p> ⑴負(fù)載類(lèi)型·························&
22、#183;····································
23、;··············12</p><p> ?、茟?yīng)力類(lèi)型 ·················
24、183;····································
25、····················13</p><p><b> UNIT FIVE</b></p><p> Text Struct
26、ure of Buildings</p><p> [1] Considering only the engineering essentials, the structure of a building can be defined as the assemblage of those parts which exist for the purpose of maintaining shape and
27、stability. Its primary purpose is to resist any loads applied to the building and to transmit those to the ground. </p><p> [2] In terms of architecture, the structure of a building is and does much more
28、 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
29、 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 ignore</p><p>
30、 [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 o
31、f construction. Artists can sometimes generate shapes that obviate any consideration of science, but architects cannot.</p><p> [4] There are at least three items that must be present in the structure of
32、 a building: </p><p> stability </p><p> strength and stiffness </p><p><b> economy</b></p><p> [5] Taking the first of the three requir
33、ements, 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.</p>
34、<p> [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
35、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. St
36、iffness is different from strength in that it directly involves how much a structu</p><p> [7] Economy of a building structure refers to more than just the cost of the materials used. Construction econom
37、y 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 o
38、f money (interest) are also factors. In most design situations, more than one structural material requires consideration. Competitive alternatives almost always exis</p><p> [8] Apart from these three pr
39、imary 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
40、 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 sim
41、ply, the structure must be appro</p><p> [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
42、 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 b
43、e adequately protected by fireproofing materials. The degree of fire resistance to be provided will depend upon a n</p><p> [10] Third, the structure should integrate well with the building's circula
44、tion 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 coo
45、rdinated 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, </p><p&
46、gt; [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 ju
47、st 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 occ
48、upant standing next to one 40 floors above the street.</p><p> [12] Sometimes the architect must make deliberate attempts to increase the apparent strength or solidness of the structure. This apparent sa
49、fety may be more important than honestly expressing the building's structure, because the untrained viewer cannot distinguish between real and perceived safety. </p><p> Reading Material A</p>&l
50、t;p> Structural Planning and design</p><p> The building designer needs to understand the behavior of physical structures under load. An ability to intuit or "feel" structural behavior is poss
51、essed 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 vit
52、al to the development of this ”sense”。</p><p> Beginning this study of forces and stresses and deformations is most easily done through quantitative methods. These two subjects form the basis for all struct
53、ural planning and design and are very difficult to learn in the abstract.</p><p> In most building design efforts, the initial structural planning is done by the architect. Ideally, the structural and mecha
54、nical 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 relati
55、onships to be developed between the building form and the structural system. A solid background in structural principles and behavior is needed to make thes</p><p> Structural design, on the other hand, is
56、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 engin
57、eer. 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 alway
58、s done by the struc</p><p> 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 exp
59、erience. 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 analys
60、is and design. If possible, this should be gained from an architectural standpoint, emphasizing the re</p><p> This study of quantitative structures can be thorough enough to permit the architect to do comp
61、letely 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 remem
62、bered 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</p><p> Reading Mate
63、rial B</p><p> Types of Loads and Types of Stress</p><p> Types of Loads</p><p> In general, loads that act on building structures can be divided into two groups; those due to gr
64、avitational 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 obj
65、ects 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 type</p><p> The snow map o
66、f 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
67、 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. </p><p> Natural f
68、orces 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
69、 building codes often require certain types of resistive construction.) A probable wind pressure map is given in Appendix N.</p><p> Earthquakes are also treated as lateral loads (at least for preliminary d
70、esign 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
71、continues in these areas. </p><p> One final type of load is an impact load, usually due to moving equipment, which occurs within or on the structure. Most stru
72、ctural 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
73、govern the design. No permanent damage is done by moderate impact load provided that it does not occur repeatedly. (An earthquake is a good example of a se</p><p> All the tables and maps referred to in thi
74、s text, as part of the appendices, provide rough data only. The designer should consult local building codes, which always take precedence. The designer also bears the Professional responsibility for increasing any recom
75、mended design loads when the situation warrants it. </p><p> Types of stress </p><p> A fundamental concept in the structural analysis of buildings is
76、 that objects are in a state of equilibrium. This means there are no unbalanced forces acting on the structure or its parts at any point. All forces counteract one another, and this results in equilibrium. The structur
77、al element or object does not accelerate because the net force acting on it is zero, but it does respond to these forces internally. It is pushed or pulled and otherwise deformed, giving off energy as heat as it resi<
78、/p><p> These stresses are named by their action or behavior (i.e., tension, compression, shear, and bending). Tensile and compressive stresses which act through the axis or center of mass of an object are eve
79、nly distributed over the resisting area and result in all the material fibers being stressed to like amounts. Shearing stresses and, more important, bending stresses are not uniform and usually result in a few fibers of
80、material being deformed to their limit while others re- main unstressed or near</p><p> Assuming for the moment that we have a material equally strong in tension, compression, shear, and bending, it would b
81、e best to load it in tension to achieve its maximum structural capacity. Compressive forces, if applied to a long slender structure, can cause buckling. Buckling always occurs under less load than would be required to fa
82、il the materials in true compression (i.e., crushing). Of course, materials are not equal in strength when loaded in different ways. Some materials have almost n</p><p><b> 第五單元</b></p>
83、<p> 課文 建筑物的結(jié)構(gòu)</p><p> [1] 如果只考慮工程要點(diǎn)建筑物結(jié)構(gòu)可以定義為保持形狀與穩(wěn)定而存在的那些部分的集合。其主要目的是抵制任何作用于建筑物上的負(fù)載,并將其傳輸?shù)降厣稀?lt;/p><p> [2] 根據(jù)建筑,建筑的結(jié)構(gòu)不止那些。它是建筑形式的不可分割的一部分并在不同程度上是那種形式的產(chǎn)物。熟練使用上,建筑結(jié)構(gòu)可以建立或加強(qiáng)建筑
84、體量和平面之間的順序和節(jié)奏。它可以直觀地主導(dǎo)或隱性。它可以發(fā)展和諧或沖突。它可以同時(shí)受限和解放。不幸的是在某些的情況下,它不能被忽略。它是物質(zhì)性的。</p><p> [3] 結(jié)構(gòu)也必須保持建筑形式的工程化。原則與物理、數(shù)學(xué)工具依據(jù)建造提供了區(qū)分理性與非理性形式的基本原理。藝術(shù)家有時(shí)可以產(chǎn)生消除任何科學(xué)考慮的形狀,但建筑師卻不能。</p><p> [4]存在至少三個(gè)必須出現(xiàn)在建筑結(jié)構(gòu)
85、上的項(xiàng)目:</p><p><b> 穩(wěn)定</b></p><p><b> 強(qiáng)度和剛度</b></p><p><b> 經(jīng)濟(jì)</b></p><p> [5] 采取這三種的需求的第一個(gè),顯然,穩(wěn)定需要保持形狀。一個(gè)不穩(wěn)定的建筑結(jié)構(gòu)意味著不平衡的力或缺乏平衡和隨之加速
86、的結(jié)構(gòu)或其構(gòu)件。</p><p> [6] 強(qiáng)度的要求意味著被選擇抵制通過(guò)結(jié)構(gòu)負(fù)載和形狀產(chǎn)生的應(yīng)力必須是足夠的。的確,一個(gè)“安全系數(shù)”是經(jīng)常被提供的,以致于在預(yù)期的荷載作用下,一個(gè)給定的材料是不強(qiáng)調(diào)一個(gè)甚至接近其破裂點(diǎn)的水平。被稱(chēng)為剛度的材料屬性是和強(qiáng)度要求是一起被考慮的。剛度不同于強(qiáng)度,因?yàn)樗苯由婕敖Y(jié)構(gòu)在荷載作用下的拉傷和偏斜多少。強(qiáng)度高但剛度弱的材料在抵抗應(yīng)用力價(jià)值方面將變形太多。</p>
87、<p> [7] 建筑結(jié)構(gòu)經(jīng)濟(jì)涉及到的不僅是材料使用費(fèi)。工程經(jīng)濟(jì)是一個(gè)復(fù)雜的主題,涉及原料、 制造、 安裝及保養(yǎng)。必須考慮設(shè)計(jì)和建設(shè)勞動(dòng)成本和能源消耗成本。建設(shè)速度和錢(qián) (利息) 的成本也是因素。在大多數(shù)的設(shè)計(jì)情況下,多個(gè)結(jié)構(gòu)材料需要考慮。競(jìng)爭(zhēng)的選擇幾乎總是存在的,選擇是不明顯的。</p><p> [8] 除了這三個(gè)主要要求,其他幾個(gè)因素是值得強(qiáng)調(diào)的。首先,結(jié)構(gòu)或結(jié)構(gòu)系統(tǒng)必須與建筑的功能相關(guān)。它不
88、應(yīng)從形式上沖突。例如線性函數(shù)要求一個(gè)線性的結(jié)構(gòu),因此不適合給有圓頂?shù)谋}g球館蓋以屋頂。同樣,劇院必須有大、 無(wú)障礙物阻擋視線的范圍,但高級(jí)餐廳可能不一定。簡(jiǎn)單地說(shuō),結(jié)構(gòu)必須適合它作為住房的功能。</p><p> [9] 第二,結(jié)構(gòu)必須是防火的。顯然,結(jié)構(gòu)系統(tǒng)必須能夠保持其完整性,至少直到居民是安全的。建筑規(guī)范規(guī)定建筑必須抗火不塌的小時(shí)數(shù)。這些結(jié)構(gòu)材料用于那些固有抗火或通過(guò)防水材料被充分保護(hù)的元素。被提供的抗火
89、程度將取決于一大批項(xiàng)目,包括空間的使用和占有荷載、 它的尺寸和建筑物位置。</p><p> [10] 第三,結(jié)構(gòu)應(yīng)也與這座大樓的流通系統(tǒng)很好地集成。它不應(yīng)與水和垃圾管道系統(tǒng),空氣調(diào)節(jié)系統(tǒng)或 (最重要的)人的運(yùn)動(dòng)有沖突。很明顯的是,各種建筑系統(tǒng)必須與設(shè)計(jì)過(guò)程相協(xié)調(diào)。人們可以設(shè)計(jì)在任何一個(gè)的系統(tǒng)內(nèi)順序的分步方式,但他們所有的設(shè)計(jì)應(yīng)以并行方式移動(dòng)完成??臻g上,建筑物的所有各部分是相互依存的。</p>
90、<p> [11] 第四,結(jié)構(gòu)必須心理和物理安全一樣,在風(fēng)中劇烈搖擺的高層建筑框架也許實(shí)際上是不危險(xiǎn)的但也許使建筑還是一樣不適宜居住。太”彈性”的輕質(zhì)樓板系統(tǒng)會(huì)使用戶(hù)感到不舒適。不被分割的豎框打斷的大玻璃窗可能相當(dāng)安全但將對(duì)臨近一個(gè)街道上的一40層樓非常不安全。</p><p> [12] 有時(shí)建筑師必須故意試圖增加結(jié)構(gòu)表面強(qiáng)度或硬度。這種明顯的安全也許比真誠(chéng)地表現(xiàn)建筑結(jié)構(gòu)更重要,因?yàn)槲唇?jīng)訓(xùn)練的觀察
91、者無(wú)法區(qū)分真正的和可預(yù)見(jiàn)的安全。</p><p><b> 閱讀材料 A</b></p><p><b> 結(jié)構(gòu)的規(guī)劃和設(shè)計(jì)</b></p><p> 建筑設(shè)計(jì)者需要了解負(fù)載下的物理結(jié)構(gòu)的行為。本能或“感覺(jué)”結(jié)構(gòu)行為的能力是通過(guò)那些已有很多涉及結(jié)構(gòu)定性和定量的分析的經(jīng)驗(yàn)獲得的。隨之而來(lái)的怎樣建立不同材料和、形狀的力、
92、應(yīng)力和變形知識(shí)對(duì)這種“感覺(jué)” 的發(fā)展至關(guān)重要。</p><p> 開(kāi)始力、應(yīng)力和變形的研究是最容易通過(guò)定量方法實(shí)現(xiàn)的。形成所有結(jié)構(gòu)規(guī)劃和設(shè)計(jì)基礎(chǔ)的這兩個(gè)主題是非常難以抽象學(xué)習(xí)的。</p><p> 在大多數(shù)建筑設(shè)計(jì)的努力下,最初的結(jié)構(gòu)計(jì)劃是由建筑師完成的。理想的情況下,結(jié)構(gòu)和機(jī)械咨詢(xún)師應(yīng)從項(xiàng)目構(gòu)想到施工竣工伴隨建筑師左右工作。但是,在大多數(shù)的情況下,建筑師必須做出一些有關(guān)結(jié)構(gòu)形式和結(jié)構(gòu)
93、體系之間被發(fā)展的關(guān)系的初始假設(shè)。在結(jié)構(gòu)的原則和行為方面的扎實(shí)背景需要做這些與任何信心合理程度有關(guān)的假設(shè)。結(jié)構(gòu)層的形狀、 所有主要支持元素的位置、 系統(tǒng)的方向性 (如果有的話(huà))主要結(jié)構(gòu)材料和跨度長(zhǎng)度的初步確定都是結(jié)構(gòu)規(guī)劃進(jìn)程的組成部分。</p><p> 另外一方面,結(jié)構(gòu)設(shè)計(jì)是由建筑師和工程師共同完成的。提供對(duì)以前的假設(shè)的合理性進(jìn)行檢查的主要結(jié)構(gòu)元素大小的初步測(cè)定是通過(guò)建筑師和工程師完成的。最后,渉及所有的零部件
94、全面的分析、結(jié)構(gòu)詳細(xì)的論述和結(jié)構(gòu)材料、施工方法細(xì)則的最終結(jié)構(gòu)設(shè)計(jì)幾乎總是由結(jié)構(gòu)工程師完成的。</p><p> 在這兩個(gè)的領(lǐng)域中,結(jié)構(gòu)規(guī)劃是比結(jié)構(gòu)設(shè)計(jì)的復(fù)雜得多。它涉及到前面提到的“對(duì)結(jié)構(gòu)的感受”或來(lái)自經(jīng)驗(yàn)的直覺(jué)。結(jié)構(gòu)設(shè)計(jì)可以從講座和書(shū)上學(xué)到,但很可能的是結(jié)構(gòu)規(guī)劃卻不能。不過(guò),一些見(jiàn)解和判斷可以從結(jié)構(gòu)分析與設(shè)計(jì)中的最小背景中發(fā)展而來(lái)。如果可能的話(huà),這應(yīng)該來(lái)自一個(gè)建筑觀點(diǎn),不論可能在哪,都強(qiáng)調(diào)數(shù)量和最終質(zhì)量之間的
95、關(guān)系,而不是來(lái)自一個(gè)工程的方法。</p><p> 雖然這種深度不是絕對(duì)必要的,但是這項(xiàng)定量結(jié)構(gòu)研究可能足夠徹底地允許建筑師完全做較小項(xiàng)目的分析。至少,它應(yīng)提供知識(shí)和可能與咨詢(xún)工程師一起工作的必要詞匯。必須記住的是,建筑師接收更多的教育是面向創(chuàng)造力的而不是工程師所做的,因此需要保持對(duì)設(shè)計(jì)的控制。它可以向建筑師提問(wèn)智能問(wèn)題并建議可行的選擇。如果結(jié)構(gòu)忽略殘缺的話(huà),一些設(shè)計(jì)決策實(shí)際上將被他人完成。</p>
96、<p><b> 閱讀材料 B</b></p><p><b> 荷載類(lèi)型及應(yīng)力類(lèi)型</b></p><p><b> 負(fù)載類(lèi)型</b></p><p> 一般情況下,作用在建筑結(jié)構(gòu)上的荷載可分為兩組 :由于地球引力產(chǎn)生的荷載和由于其他自然因素和元素引起的荷載。重力負(fù)荷可以進(jìn)一步
97、分為兩個(gè)組別: 活荷載和恒荷載。建設(shè)活荷載包括在結(jié)構(gòu)內(nèi)或它的頂部上的人和大多數(shù)可移動(dòng)的物體。雪是活荷載。大鋼琴、 冷藏室或水床也是。附錄O代表性地提供了一些在建筑結(jié)構(gòu)內(nèi)占據(jù)的各種類(lèi)型的活荷載。研究證實(shí)了這些數(shù)字表示一個(gè)結(jié)構(gòu)生命期內(nèi)活荷載的可能最大值。這種負(fù)荷很少會(huì)被意識(shí)到。在空間使用上的意外變化更有可能。人們可以感覺(jué)如果一個(gè)廢棄的學(xué)校用作 (存儲(chǔ)保齡球) 的倉(cāng)庫(kù)可能導(dǎo)致的問(wèn)題。另外一方面,恒載一般包括建筑物內(nèi)的不動(dòng)的物體。(內(nèi)部和外部)
98、 的墻壁、 地板、 機(jī)械電氣設(shè)備和結(jié)構(gòu)元素本身都是恒載的例子。</p><p> 附錄 N中的雪地圖提供最大的雪荷載,它可以在美國(guó)各地被合理預(yù)測(cè)。像活荷載的值,這樣大的降雪很少發(fā)生。然而,我們必須為一些可能性水平設(shè)計(jì)而不應(yīng)該忘記正如發(fā)生于 1974 年美國(guó)東南部的超過(guò)500毫米降雪的情況,它導(dǎo)致許多小建筑毀壞。</p><p> 自然力不是由于作用在建筑上的重力,而是由風(fēng)和地球地震提供
99、的。風(fēng)荷載是橫向的負(fù)荷,它隨高度而產(chǎn)生不同強(qiáng)度。(颶風(fēng)和龍卷風(fēng)呈現(xiàn)了特別設(shè)計(jì)的問(wèn)題,并且當(dāng)?shù)亟ㄖㄒ?guī)通常需要某些抵制施工的類(lèi)型。) 一個(gè)可能的風(fēng)壓地圖被載于附錄N。</p><p> 地震(至少因?yàn)槌醪皆O(shè)計(jì)意圖)也被視為橫向荷載,但眾所周知,在地震中的建筑物也受到垂直力的作用。設(shè)計(jì)方法因如龍卷風(fēng)和地震的災(zāi)難荷載而不完善,并且研究在這些領(lǐng)域繼續(xù)前進(jìn)。</p><p> 最終類(lèi)型的負(fù)載是一
100、種沖擊荷載,通常,由于發(fā)生在結(jié)構(gòu)內(nèi)或結(jié)構(gòu)上的移動(dòng)設(shè)備引起的。大多數(shù)結(jié)構(gòu)材料能承受一種比慢慢地應(yīng)用的負(fù)載較高規(guī)模的突然和臨時(shí)的負(fù)載。由于這個(gè)原因,當(dāng)這些荷載控制設(shè)計(jì)時(shí),指定的許用應(yīng)力幅度是基本增長(zhǎng)的。無(wú)永久性損傷是通過(guò)提供不反復(fù)出現(xiàn)的適度沖擊荷載實(shí)現(xiàn)的。(地震是一個(gè)嚴(yán)重和重復(fù)沖擊荷載的好例子。</p><p> 所有涉及在此文中的圖表作為這些附錄的一部分,它只提供粗略的數(shù)據(jù)。設(shè)計(jì)者應(yīng)咨詢(xún)當(dāng)?shù)厥冀K優(yōu)先的建筑法規(guī)。當(dāng)
101、情況需要時(shí),設(shè)計(jì)人員也承擔(dān)著增加任何推薦設(shè)計(jì)荷載的職業(yè)責(zé)任。</p><p><b> 應(yīng)力類(lèi)型</b></p><p> 建筑結(jié)構(gòu)分析中的一個(gè)基本概念是對(duì)象處于平衡的狀態(tài)。這意味著作用在結(jié)構(gòu)或其部件上的任何一點(diǎn)沒(méi)有不平衡力。所有力都一個(gè)一個(gè)抵消,這將導(dǎo)致力的平衡。因?yàn)樗鼪](méi)有凈力作用在結(jié)構(gòu)元素或?qū)ο笊?,故它不加速,但是它?duì)這些內(nèi)力產(chǎn)生響應(yīng)。它是受推或受拉的,否則它
102、會(huì)變形, 釋放出和它抗拒力一樣的能量。不同類(lèi)型和規(guī)模的內(nèi)部應(yīng)力伴隨著提供這種阻力的變形。</p><p> 這些應(yīng)力是通過(guò)它們的行動(dòng)或行為 (即,拉伸、 壓縮、 剪切,和彎曲) 命名的。通過(guò)作用在軸或?qū)ο筚|(zhì)心的拉伸和壓縮應(yīng)力是均勻地分布在抗區(qū)上的并將產(chǎn)生所有像數(shù)額一樣被強(qiáng)調(diào)的材料光纖。更重要的是,剪應(yīng)力、彎曲應(yīng)力并不一致,并通常產(chǎn)生一些物質(zhì)纖維,但其他材料保持無(wú)應(yīng)力或接近這樣時(shí)這種材料將變形到極至。到目前為止,
103、彎曲是結(jié)構(gòu)上承受荷載的最有效方式。</p><p> 假設(shè)目前我們?cè)诶臁?壓縮、 剪切,和彎曲上有同樣強(qiáng)烈的的材料,最好在張力上加載它以實(shí)現(xiàn)其最大的結(jié)構(gòu)容量。應(yīng)用到一個(gè)細(xì)長(zhǎng)結(jié)構(gòu)上的壓力會(huì)導(dǎo)致屈曲。屈曲總是將要在真正壓縮(即粉碎)使材料失效的較小荷載發(fā)生。當(dāng)然,當(dāng)以不同方式加載時(shí),材料將在強(qiáng)度上不平等。一些材料幾乎沒(méi)有拉伸強(qiáng)度,并且難以概括。正如后續(xù)章節(jié)解釋的那樣,剪力將引起拉伸和壓縮 ;且彎曲實(shí)際上是剪拉壓的
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