【0179】9[畢業(yè)設(shè)計(jì)]某住宅樓工程畢業(yè)設(shè)計(jì)（清單）
【0179】9[畢業(yè)設(shè)計(jì)]某住宅樓工程畢業(yè)設(shè)計(jì)（清單）,0179,畢業(yè)設(shè)計(jì),住宅樓,工程,清單
It is said that necessity is the mother of all invention. If that is the case, then the need for striking, elegant cable-stayed bridges that can span greater lengths and be more easily maintained over the course of longer lives has yielded a significant new invention that may well benefit bridge designers the world over.
Driven by a desire to push the design of single-plane cable-stayed bridges beyond their current limits—both in span length and in aesthetic appeal—while still delivering an economic solution that is easy to construct and maintain, FIGG, an engineering firm based in Tallahassee, Florida, has created a novel system for routing stay cables from one end of a bridge deck, through the bridge’s pylon, and then down to the other end of the deck in a way that precludes the possibility of cable-to-cable interactions.
The innovation has been employed on two new bridges—the Veterans’ Glass City Skyway Bridge, which carries Interstate 280 across the Maumee River in Toledo, Ohio (see “Ohio DOT Endorses Design for Maumee River Crossing,” Civil Engineering, September 2000, page 12), and the Penobscot Narrows Bridge and Observatory, which carries U.S. Route 1 over the Penobscot River in southeastern (“down east”) Maine near the coastline (see “Observatory to Cap Maine Crossing,” Civil Engineering, April 2004, pages 15–17).
The cradle offers benefits both during construction and over the life of the bridges. Most important of all, it permits the use of the largest number of strands within a single stay cable in the world: 156, an increase of more than 70 percent over the second-highest number known to have been used in the United States. It also makes it possible to increase the distance between stay cables by approximately 50 percent when used with precast delta frames to facilitate a single plane of stay cables, resulting in aesthetically superior designs. This is accomplished by having all the strands parallel as they travel from the anchors at the deck level through the cradle in the pylon and back to the deck. Individual sleeve pipes located within the cradle system enable each strand to act independently of adjacent strands. This also permits the cables to be much larger and to be spaced farther apart, which translates into longer spans.
Furthermore, the cradle system lowers initial costs by reducing the amount of materials and labor needed because no anchorages in the pylon are required. This simplifies construction operations by allowing all of the cable-stressing operations to be performed at the bridge deck level rather than within the (often restricted) confines of the pylon, high above the bridge deck. The system also includes removable “reference” strands in each stay cable that provide a simple, reliable method for verifying the condition of the stay cables in the future. Because the cradle system does not require strands to be grouted, they can be individually removed, inspected, and replaced, even when there is traffic on the bridge. Bridge owners can thus safely and accurately assess the conditions of the stay cables at any time over the course of the bridge’s life. In the case of the Maine bridge, new strand materials can be tested
side-by-side with traditional materials in an actual setting, as opposed to a process of computer simulation.
What is more, the cradle system makes possible the use of a wider variety of pylon designs—some with much smaller and more elegant cross-sectional shapes—that can be constructed more economically. Engineers can thus design pylons that are far more unusual and aesthetically pleasing than has been the case in the past.
The cradle design works with the natural flow of forces because the forces transmitted through the cradle naturally compress the pylon in an efficient manner, the stresses being applied radially along the curve of the cradle (see the illustrations on page 41). In traditional systems, anchorages within the pylon required large tension ties to resist the high splitting forces that would be generated. Using the cradle system eliminates this requirement and further enhances the elegance of the pylon shapes.
The development of this new technique began in early 2000. The Ohio Department of Transportation (ODOT) and the Toledo Metropolitan Area Council of Governments had formed what was called the Maumee River Crossing Task Force Design Committee to assess and communicate the communities’ perspective on the developing design. The task force chose glass as the theme for the new cable-stayed bridge. Meetings involving a diverse cross section of the community had made the public’s views clear: the bridge was to feature glass in a very visible and striking way in recognition of Toledo’s industrial heritage as a leader in the glass industry. Many families in the area had worked in the local glass industry for generations, and it was important to them that the crossing be a symbol of the “Glass City,” as Toledo has come to be known. The public was also of the opinion that the bridge design should champion a product that had been of the utmost importance to the area’s economy. The task force further determined that residents wanted the bridge design to be light, simple, and elegant.
FIGG led two community workshops, or design charettes, during which the public was presented with a variety of aesthetic options. Community voting showed a clear preference for a single-pylon design. The consensus was that by creating a single tall pylon—403 ft (123 m)—using glass on the top 196 ft (60 m) and on all four sides, the new bridge would be visually stunning. In keeping with this directive, the top of the pylon takes on a prismatic shape, its panels of treated glass reflecting sunlight during the day on all four sides. Behind the glass are light-emitting diodes (LEDS) that enable the pylon to stand as a beacon at night. (The led fixtures are controlled remotely and capable of literally millions of color combinations. In fact, various color schemes have been preprogrammed, some schemes marking major holidays and others exhibiting team colors for statewide sporting events.)
有人說(shuō)需求是一切發(fā)明的母親。如果真的是這樣，那么引人注目的，優(yōu)雅的斜拉橋能夠橫跨更大的距離和使得橋梁在更長(zhǎng)的使用壽命中的維護(hù)變得更簡(jiǎn)單將是一項(xiàng)可以讓全球橋梁設(shè)計(jì)者都受益的重要的新發(fā)明。
在推動(dòng)單面斜拉橋超越現(xiàn)有極限（在跨度和美觀兩方面）的需求的驅(qū)使下，同時(shí)用一種在建造和維護(hù)過(guò)程中都經(jīng)濟(jì)的解決方法，F(xiàn)IGG，一家位于Florida首府Tallahassee的工程公司，發(fā)明了一個(gè)新穎的體系。該體系的斜拉索的傳力路徑是將力從橋面板的一端通過(guò)橋塔傳下至橋面板的另一端。這種方法就可以排除斜拉索間互相作用的可能性。
這種創(chuàng)新的方法被應(yīng)用在兩座新橋上。一座是老兵玻璃城航線大橋，這座大橋連接著280洲際公路橫跨流經(jīng)Toledo, Ohio的Maumee河；另一座是Penobscot 紐約灣海峽大橋和天文臺(tái)，這座大橋連接著美國(guó)1號(hào)公路橫跨位于靠近海岸線的Maine 洲東南面的Penobscot河。
這個(gè)支架為橋梁的建造過(guò)程和其使用壽命中都帶來(lái)了好處。最重要的是，它使得一根拉索中繩的股數(shù)達(dá)到了世界范圍內(nèi)的最大值：156。這個(gè)值比美國(guó)境內(nèi)用過(guò)的第二多的股數(shù)多了70％。也使得當(dāng)它用于預(yù)制的三角形框架（可使得單面斜拉索更方便）的斜拉索的距離增加大約50％成為了可能。這樣就可以實(shí)現(xiàn)美學(xué)上的非凡設(shè)計(jì)。這是通過(guò)在繩股從橋面板水平面的支座穿過(guò)橋塔中的支架然后返回到橋面板過(guò)程中使得所有的繩股平行來(lái)實(shí)現(xiàn)的。位于支架系統(tǒng)內(nèi)的獨(dú)立套管使得每股繩都能不受相鄰繩股的影響而單獨(dú)作用。這也使拉索可以做得比以前大得多并且拉索間的距離也可以更大，也就是說(shuō)橋梁可以橫跨更大的距離。
而且，由于橋塔內(nèi)不需要支座所以材料的用量和人力的使用都減少了，從而支架系統(tǒng)降低了橋梁的初始成本。由于拉索的張拉操作都在橋面板上進(jìn)行而不是在高高的橋塔上那么局限的范圍內(nèi)進(jìn)行所以施工操作也變得簡(jiǎn)化了。這個(gè)體系還包括在每個(gè)斜拉索中都有可移動(dòng)的參考繩股，這樣為將來(lái)檢驗(yàn)拉索的使用情況提供了一個(gè)簡(jiǎn)單可靠的方法。因?yàn)橹Ъ芟到y(tǒng)不要求用水泥漿添塞繩股，所以即使是在橋上有車(chē)輛和行人的情況下它們可以被單獨(dú)地移除，檢查和替換。這樣一來(lái)橋梁的業(yè)主在橋梁的使用壽命期間隨時(shí)都可以安全地，準(zhǔn)確地對(duì)拉索的情況進(jìn)行評(píng)估。在Maine橋的案例中，新的繩股材料和傳統(tǒng)的材料可以在實(shí)際中進(jìn)行并行的測(cè)試而不需要用電腦仿真。
而且，支架系統(tǒng)使得橋塔設(shè)計(jì)的多樣化成為了可能，有些可以采用小得多的更優(yōu)雅的截面形式，這樣施工也更經(jīng)濟(jì)。工程師在將來(lái)也就可以設(shè)計(jì)出不尋常的，更美的橋塔了。
支架的設(shè)計(jì)應(yīng)該和力的自然傳遞結(jié)合起來(lái)因?yàn)榱νㄟ^(guò)支架力以一種有效的方式擠壓橋塔。應(yīng)力沿著支架的曲線輻射地分布。在傳統(tǒng)的系統(tǒng)中，橋塔內(nèi)的支座要求連接有很大的拉力以抵抗可能產(chǎn)生的突發(fā)的力。支架系統(tǒng)就沒(méi)有這個(gè)要求而且進(jìn)一步加強(qiáng)了橋塔形狀的美觀性。
這項(xiàng)新技術(shù)的開(kāi)發(fā)始于2000年年初，俄亥俄交通部和托萊多城市地區(qū)政府委員會(huì)成立了一個(gè)稱為Maumee 河跨越任務(wù)力學(xué)設(shè)計(jì)委員會(huì)的機(jī)構(gòu)對(duì)委員會(huì)的深化設(shè)計(jì)的效果圖進(jìn)行交流和評(píng)估。任務(wù)力學(xué)設(shè)計(jì)委員會(huì)把玻璃選作新型斜拉橋的主題。包括各種各樣的橫截面的委員會(huì)會(huì)議讓大眾的觀點(diǎn)明朗起來(lái)：橋?qū)?huì)以醒目的和震撼人心的方式成為玻璃的象征。這座橋代表著托萊多在玻璃行業(yè)中領(lǐng)先的工業(yè)傳統(tǒng)。很多家庭好幾代人都在當(dāng)?shù)夭ＡЧI(yè)中工作。隨著托萊多的出名，讓這座橋梁成為玻璃之城的象征是很重要的。人們還認(rèn)為橋梁的設(shè)計(jì)應(yīng)
該使得一個(gè)產(chǎn)品成為冠軍產(chǎn)品對(duì)地區(qū)經(jīng)濟(jì)的發(fā)展來(lái)說(shuō)是最重要的。任務(wù)力學(xué)設(shè)計(jì)委員會(huì)還進(jìn)一步?jīng)Q定居民們希望橋的設(shè)計(jì)應(yīng)該輕盈，簡(jiǎn)潔和優(yōu)雅。
FIGG成立了2個(gè)公眾車(chē)間或者說(shuō)設(shè)計(jì)研討組，在此期間向大眾展示各種外觀。大眾投票的結(jié)果清楚地顯示人們想要的是只有一個(gè)橋塔的設(shè)計(jì)。大家一致認(rèn)為應(yīng)該建造一個(gè)高為403英尺（123米）的橋塔，并在其上面的196英尺（60米）部分和橋塔的四周都使用玻璃。這座新橋?qū)?huì)看起來(lái)驚艷無(wú)比。為了達(dá)到這個(gè)目標(biāo)，橋塔的頂部采用了棱鏡的形狀。在白天，經(jīng)過(guò)處理的玻璃面會(huì)從四個(gè)方向反射太陽(yáng)光。在玻璃里面放置了發(fā)光二極管（LED燈），這樣在夜間橋塔就可以像一個(gè)燈塔般屹立。（LED設(shè)備由遙控控制，它可以形成數(shù)百萬(wàn)種漸變的顏色組合。有一些組合標(biāo)志著主要的節(jié)日而另一些則表示洲內(nèi)體育賽事團(tuán)隊(duì)的顏色。）
收藏