【正文】 Structural design involves determining the most suitable proportions of a structure and dimensioning the structural elements and details of which it is posed. This is the most highly technical and mathematical phase of a structural engineering project, but it cannot and certainly should notbe conducted without being fully coordinated with the planning and construction phases of the project. The successful designer is at all times fully conscious of the various considerations that were involved in the preliminary planning for the structure and, likewise, of the various problems that may later be encountered in its construction. Proportion 比, 比率,均衡, 相稱,份, 部份,大小。鋁 梁已經(jīng)在橋梁結(jié)構(gòu)以及一些框架建筑中使用。然后，通常通過先張法或者 后張法，他們給混凝土施加預(yù)應(yīng)力。還有另外一個好處就是鋼 在混凝土中不會生銹。 They also plement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where both pression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tension will develop. Concrete and steel also form such a strong bondthe force that unites themthat 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. Contraction 壓縮 expansion 膨脹 bond 結(jié)合 unite slip 滑動 rust .(使)生銹 corrode 腐蝕 alkaline reaction n.[化] 堿性反應(yīng) 他們還可以以另一種方式相互補(bǔ)充：他們 有幾乎相同的壓縮和膨脹率。成分的 不同比例可以制造出不同強(qiáng)度和重量的混凝 土。 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 powder. 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。鋼材，主要是 鐵合金和少量的碳，在那時要通過費(fèi)力的過 程才能提煉出來，這限制它只能用于一些特 殊用途比如劍刃上。例如， 希臘帕提農(nóng)神廟的立柱，為了插鐵棒在立柱 中鉆孔，這些鐵棒現(xiàn)在已經(jīng)銹蝕了。幸運(yùn)的是，工程師 從錯誤中吸取教訓(xùn)，因此現(xiàn)在通常要在風(fēng)洞 試驗室中進(jìn)行橋梁的縮尺模型試驗以確定其 空氣動力阻力。大橋在風(fēng)中 扭動的場面令人震撼，只使用了三個月。 美國華盛頓州Taa Narrows大橋倒塌的錄 像。如果一片梁要支撐作 用在其上的荷載，梁自身必須要有足夠的強(qiáng) 度來平衡這個重量。 and those that act upon it with a rotating or turning motion. Forces that act at an angle are a bination of horizontal and vertical forces. Since the structures designed by civil engineers are intended to be stationary or stable, these forces must be kept in balance. The vertical forces, for example, must be equal to each other. If a beam supports a load above, the beam itself must have sufficient strength to counterbalance that weight. The horizontal forces must also equal each other so that there is not too much thrust either to the right or to the left. And forces that might pull the structure around must be countered with forces that pull in the opposite direction. act on ...起作用,作用于 act 產(chǎn)生…..的效果，擔(dān)當(dāng)，見效 vertical 垂直的 horizontal 水平的 sideways rotating轉(zhuǎn)動的, 旋轉(zhuǎn)的 turning , 轉(zhuǎn)向 motion , 動作 stationary固定的 stable counterbalance vt使平衡 thrust 推力 opposite direction相反方向，反向 總之，這三個力會作用在結(jié)構(gòu)上：豎直的那些向上或向下作用的力；水平的—那些向 一側(cè)作用的力；以及那些使旋轉(zhuǎn)或轉(zhuǎn)動的作 用力。除了拉力和壓力以外，還有另一種 力作用于結(jié)構(gòu)上，也就是剪力，我們定義使 材料趨于沿著力的作用線斷裂的力為剪力。 The modern engineer must also understand the different stresses to which the materials in a structure are subject. These include the forces of pression and tension. In pression the material is pressed or pushed together。當(dāng)現(xiàn)代工程師設(shè)計一個結(jié)構(gòu)時，他 要考慮所有組成材料的總重量。但更早的時期的工 程師也有過失敗。軸向壓力來自于結(jié)構(gòu)的其它部份 對其的傳導(dǎo)。s in Rome. They are massive structures with thick stone walls that counteract the thrust of their great weight. Thrust is the pressure exerted by each part of a structure on its other parts. Pantheon 帕提儂神廟 Colosseum ，角斗場 Hagia Sophia 圣索非亞教堂 Istanbul 伊斯坦布兒(土耳其首都) renaissance文藝復(fù)興時期 cathedral gothic church dome ，穹頂 duomo , 中央寺院 Florence 佛羅倫薩 St. Peter‘s 圣彼得大教堂 massive , 大塊的, 魁偉的, 結(jié)實的 counteract ，對抗 thrust 推力引申為軸向壓力 exert 施加(壓力等) ，作用,施加 許多偉大的建筑很早就修建了現(xiàn)在仍然還 存在并在使用中。必須 考慮安全因素，因為施工很危險。在其它情況下, 土木工 程師被分配到其它領(lǐng)域的項目上工作。在建筑設(shè)計中, 工程師經(jīng)常作為建筑或結(jié)構(gòu)公司的顧問。許多工程師, 通常在一起工作組成一個 團(tuán)隊，這個團(tuán)隊包括測量員、土力學(xué)方面的 專家和設(shè)計施工方面的專家，來參與制定這 些可行性研究。研究包括勘測工程位置的地形和地 基特點(diǎn)。 Civil engineering projects are almost always unique。 Research is one of the most important aspects of scientific and engineering practice. A researcher usually works as a member of a team with other scientists and engineers. He or she is often employed in a laboratory that is financed by government or industry. Areas of research connected with civil engineering include soil mechanics and soil stabilization techniques, and also the development and testing of new structural materials. soil mechanics finance ...經(jīng) 費(fèi), 負(fù)擔(dān)經(jīng)費(fèi) soil stabilization土壤加固法，研究是科學(xué)和工程實踐的當(dāng)中最重要的一 個方面。從而, 他們會得到在職的培 訓(xùn)，這個培訓(xùn)將向管理人員證明他們將理論轉(zhuǎn)化為 實踐的能力。 或他們也許喜歡 與政府機(jī)構(gòu)當(dāng)中處理水資源的機(jī)構(gòu)之一共事。 or they may prefer to work with one of the government agencies that deal with water resource. Indeed, the choice is large and varied.近年來，許多不同的公 司和政府機(jī)構(gòu)為爭奪工程師而競爭。為準(zhǔn)備使學(xué)生成為一名土木工程師, 這些專業(yè) 課程可能會涉及諸如大地測量、土力學(xué)，或水力學(xué)。 因此,再一次充分說明, 工程師 負(fù)責(zé)（承擔(dān)）的工程在許多不同和重要的方 面影響社會,這些方面是他們所知道的。但如果不給計算機(jī)清楚和準(zhǔn) 確指令和信息，換句話說，一個好程序，它 也是無用的。 統(tǒng)計數(shù)學(xué)的一個重要方面是概率, 它涉及當(dāng) 有改變問題的結(jié)果的不同的因素, 或變量時， 可能會發(fā)生什么。許多政府管轄部門 還有（一套）認(rèn)證程序，這一程序要求工科 畢業(yè)生在他們能積極地開始（從事）他們的 事業(yè)之前，通過（認(rèn)證）考試, 這種考試類似 于律師職業(yè)里的律師考試一樣。 In the university, mathematics, physics, and chemistry are heavily emphasized throughout the engineering curriculum, but particularly in the first two or three years. Mathematics is very important in all branches of engineering, so it is greatly stressed. Today, mathematics includes courses in statistics, which deals with gathering, classifying, and using numerical data, or pieces of information. mathematics curriculum branch n. (學(xué)科)分科 stress 強(qiáng)調(diào) courses ,路線 statistics n. 統(tǒng)計學(xué),統(tǒng)計 deal with涉及，處理 An important aspect of statistical mathematics is probability, which deals with what may happen when there are different factors, or variables, that can change the results of a problem. Before the construction of a bridge is undertaken, for example, a statistical study is made of the amount of traffic (which) the bridge wi