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1、<p>  Long and light——《Bridge design & engineering》</p><p>  Closure of the main span on the Sundoya Bridge in Norway is expected to take place in the first week after Easter. This graceful crossing

2、, the second longest of its type in the world, is being built in situ using high performance concrete </p><p>  Sundoya Bridge is situated in one of Norway's most scenic areas, only 100km south of the Ar

3、ctic Circle. The 538m-long bridge spans Sundet, and when it is complete will provide a ferry-free road connection between Sundoya and the mainland. It is located some 35km west of the city of Mosjoen, close to highway 78

4、 between Mosjoen and Sandnessjoen. </p><p>  It will be the second large bridge project connecting Alstenoya to the mainland, coming more than 12 years after the Helgeland Bridge was opened. The region is no

5、 stranger to world-record scale bridges ?the Helgeland Bridge's 425m long main span was the longest cable-stayed span in the world when it opened in 1992. </p><p>  Sundoya Bridge is divided into three s

6、pans; it has a main span of 298m and two side spans of 120m. The main span will be the second longest span in the world for a continuous post-tensioned cast in place box section concrete bridge. </p><p>  In

7、 terms of its design, consultant Dr Ing Aas-Jakobsen has followed a similar approach to that taken for the Raftsundet Bridge, opened in 1998, to which the Sundoya Bridge will almost be a twin. The two bridges have identi

8、cal main spans, but Raftsundet has four spans as opposed to Sundoya's three. Contractor AS Anlegg, which is part of the joint venture building Sundoya, was also the contractor on the Raftsundet Bridge, and architect

9、Boarch Arkitekter has also worked on the two schemes. </p><p>  In January 2001 the joint venture company AF Sundoybrua won the contract from client Statens Vegvesen to build the Sundoya Bridge. This joint v

10、enture consisted of the contractors Reinertsen Anlegg and NCC Construction. </p><p>  High performance concrete is central to the design of the bridge ?both normal weight HPC and lightweight HPC. Normal weig

11、ht concrete, at approximately 2500kg/m3, is used for the 120m side spans, while lightweight concrete, which weighs in at about 1970kg/m3, is used for construction of the 298m main span. This enables construction to proce

12、ed using the balanced cantilever method. </p><p>  Local rock from Norway is used as the aggregate for the normal weight concrete, but the lightweight concrete required an imported solution. Normally the agg

13、regate used for lightweight concrete in Europe is expanded clay or shale, but this material has high levels of absorption and for this reason, regulations prevent such concrete from being pumped. </p><p>  I

14、n order to address this, the contractor adopted a similar solution to that used on Raftsundet Bridge ?importing Stalite aggregate from South Carolina in the USA. Stalite is produced through thermal expansion of high qual

15、ity slate, and results in a lightweight aggregate that gives concrete of very high strength at low unit weights. Its low absorption of approximately 6% and high particle strength are two of the factors that allow Stalite

16、 to achieve high strength concrete in excess of 82.7MPa, th</p><p>  According to AF Sundoybrua quality manager Jan-Eirik Nilsskog, this material has given a very good result. It produces concrete that is ea

17、sy to pour into the formwork and it gives a good surface finish, he says. It is being pumped some 120m along the bridge deck to the concreting position. Concrete is produced by a transportable mobile plant located only 1

18、km from the bridge site. Constant monitoring of the concrete weight is necessary to ensure that the cantilevers are properly balanced. This is</p><p>  The project began in January 2001 at Aker Verdal with t

19、he production of caissons for the pier bases. In May 2001 the two caissons were towed 500km north to the bridge site. </p><p>  The bridge is being poured in situ using special mobile construction equipment

20、developed by NRS. The cycle for construction of each 5m wide bridge segment is a week, and two mobile units are being used on the Sundoya Bridge. These particular units were built for AS Anlegg to use on the Varodden Bri

21、dge in Kristiansand in Norway, and they have also been used by the same contractor on the Rafsundet Bridge. The design of the central part of the main span of the bridge is based on the use of lightwei</p><p&g

22、t;  The structure is a single cell, prestressed rectangular box girder, largely built using the travelling formwork system from NRS. The box width is 7m and its depth varies from 3m at the centre of the span to 14.5m ove

23、r the piers. Close to the abutments, concrete of quality C25 will be used inside the box girder as ballast. In addition, the designers have included the necessary elements inside the box girder in order to allow the poss

24、ible addition of post-tensioning cables in the future. The long-</p><p>  The pier shaft is formed with twin legs, which are hollow inside. The pier shafts incorporate permanent prestressing cables and they

25、have a constant wall thickness and a width that varies parabolically over their height. </p><p>  Temporary tie-down piers are used to construct the bridge - they are located 35m into each 120m-long side spa

26、n from the main piers. Each consists of an I-shaped shaft, which is tied down to the ground using rock anchors and connected to the box girder by means of prestressing cables. The purpose of these structural elements is

27、to support the cantilever and prevent rotation in strong winds. Once the bridge superstructure is complete and the main pier prestressing is fully tensioned, the temporary</p><p>  The location of the bridge

28、, only about 100km south of the Arctic Circle, has meant that special measures have to be introduced to allow construction work to continue all year round. Apart from the obvious need to provide site lighting for much of

29、 the wintertime, the challenge of concreting in temperatures which can be as low as 0 C has to be overcome. Hot concrete is produced for the bridge ?sometimes up to 30 C and the formwork has to be insulated to keep the c

30、oncrete warm. Electric heating cab</p><p>  Construction of the new bridge began in January 2000 and is expected to be complete in September this year. The construction of the cantilever started in summer la

31、st year and is due to be finished in April. When Bd&e went to press, the project was on schedule for opening to traffic in late autumn.</p><p>  Project Team </p><p>  Client: Statens Vegves

32、en</p><p>  Contractor: AF Sundoybrua (AS Anlegg, NCC Construction) </p><p>  Consultant: Dr Ing Aas-Jakobsen</p><p>  Architect: Boarch Arkitekter</p><p>  超輕大跨度橋——Sun

33、doya</p><p>  挪威的在 Sundoya 橋上的主跨有望在復(fù)活節(jié)的后第一個(gè)星期望合龍. 它是一座大跨度的,在世界的它的同類型中第二長(zhǎng),建造在 situ 的長(zhǎng)大橋。 </p><p>  Sundoya橋位于挪威的風(fēng)景最好的區(qū)域之一,距北極圈以南只有100 km. 538 m長(zhǎng)的橋跨跨越 Sundet河 ,而且它將會(huì)是連結(jié) Sundoya 和大陸的通道. 橋址位于 Mosjoe

34、n城往西35 km, 在 Mosjoen 和 Sandnessjoen 之間的第 78 公路結(jié)束. </p><p>  它將會(huì)是連結(jié) Alstenoya 到大陸的第二大橋,在Helgeland 橋12 年后建成. 這個(gè)區(qū)域?qū)τ谑煜蛄菏澜缂o(jì)錄的人并不陌生,當(dāng)它開通的時(shí)候 ,Helgeland 橋的 425 m 長(zhǎng)的主跨是世界最長(zhǎng)的斜拉橋的,從1992起到現(xiàn)在. </p><p>  Su

35、ndoya 橋被區(qū)分為三個(gè)跨徑:它有 298 m 的一個(gè)主跨和二個(gè)120 m 的邊跨. 長(zhǎng)的主跨使它成為世界第二跨度的后張預(yù)應(yīng)力連續(xù)箱梁鋼構(gòu)橋. </p><p>  以它的設(shè)計(jì)原則,顧問Ing Aas- Jakobsen博士提到它的設(shè)計(jì)方式是效仿在1998年建成的Raftsundet 橋,到時(shí)候它和Sundoya 橋?qū)?huì)幾乎是雙胞胎. 二座橋有同一的主跨, 但是 Raftsundet 有四個(gè)跨度而Sundoya

36、's 只有三個(gè). 承包商As Anlegg ,是投資Sundoya 的一個(gè)投資方,以前同時(shí)也是 Raftsundet 橋的承包商,而且建筑師 Boarch Arkitekter 也同時(shí)是此兩橋的建設(shè)單位. </p><p>  在 2001 年1月合資公司 AF Sundoybrua 和客戶Statens egvesen 簽訂了建設(shè)合同,是 Sundoya 橋的主要投資方. 這一個(gè)共同投資由承包商 Rei

37、nertsen Anlegg 和 NCC 建筑所組成。</p><p>  高強(qiáng)混凝土是此橋的設(shè)計(jì)是主要組成部分,包括正常的重量 HPC 和輕量級(jí) HPC。普通混凝土,在大約 2500 公斤/m3容重 ,用在兩個(gè)120 m 邊跨上;高強(qiáng)混凝土,容重在大約 1970 公斤/m3,作為 298 m 主跨的建筑材料. 這使建筑能夠著手進(jìn)行使用懸臂施工法。</p><p>  從挪威來的本地的巖石

38、被用當(dāng)做邊跨普通混凝土的集料,但是高強(qiáng)混凝土需要進(jìn)口石料,挪威本土并沒有. 能被用作歐洲的輕量級(jí)高強(qiáng)混凝土集料的是擴(kuò)大泥土或頁(yè)巖,但是這材料有高吸水性。因?yàn)檫@個(gè)理由,混凝土不能采用泵送。 </p><p>  為了解決這個(gè)難題,承包商采用了在 Raftsundet 橋上用過的相似的解決辦法。采用從美國(guó)的南卡羅萊那進(jìn)口來的 Stalite 集料. Stalite集料通過加熱高容重的石板,使其內(nèi)部產(chǎn)生膨脹而生成一種輕

39、量級(jí)在單位抗壓重非常高的石料。它的低吸收大約 6%和高的粒子力量是兩個(gè)允許 Stalite 超過 82.7 MPa的因素。 制造業(yè)者聲稱,它和水泥漿糊的合計(jì)束縛和兼容性減少微- 裂痕而且提高耐久性,而且它的低吸收制造混合而且泵送是容易的. </p><p>  依照 AF Sundoybrua 項(xiàng)目經(jīng)理Eirik Nilsskog 的說法 ,這材料已經(jīng)給一個(gè)非常好的性能. 它容易被注入結(jié)構(gòu)框架,而且表面平整。他說

40、,它能被抽120 m,沿著需要凝結(jié)的橋面板位置. 混凝土在距橋只有 1 km的一個(gè)可運(yùn)輸?shù)囊苿?dòng)場(chǎng)地生產(chǎn). 不時(shí)的重量監(jiān)控是必需的,以便懸臂施工時(shí)能適當(dāng)?shù)钠胶? 這在每次運(yùn)送前都需要被測(cè)試. </p><p>  計(jì)劃在 2001 年1月在和彈藥箱的制造廠地Aker Verdal 為碼頭開始. 在2001 年5月二個(gè)彈藥箱將被拖放到距橋位置的北方500 km處. </p><p>  建筑在

41、situ的橋梁應(yīng)用了被 NRS改良過的特別移動(dòng)的建筑儀器.每 5 m 的橋面板澆筑需要一個(gè)星期, Sundoya 橋上一共使用了二個(gè)可動(dòng)裝置. 這些特別的裝置專為As Anlegg生產(chǎn),其已經(jīng)在挪威的Kristiansand 的 Varodden 橋上使用,現(xiàn)在他們也已經(jīng)被相同承包商橋用在Rafsundet 上。當(dāng)結(jié)構(gòu)的其他部份使用較標(biāo)準(zhǔn)的類型 C65 的時(shí)候 , 橋的主跨的中央部份的設(shè)計(jì)以輕量級(jí)具體物 LC60 的使用為基礎(chǔ)。 因?yàn)楹?/p>

42、水的強(qiáng)腐蝕性,混凝土的質(zhì)量一定需要特別好的. </p><p>  結(jié)構(gòu)是單獨(dú)部分,先期預(yù)應(yīng)力的矩形箱形結(jié)構(gòu),大量的被移動(dòng)的NRS 的 formwork 系統(tǒng)生產(chǎn)應(yīng)用。 箱梁寬度是 7 m ,而且它的高度從在跨中的3 m 變化到在碼頭支座上的 14.5 m。和鄰接結(jié)構(gòu)相似,C25 的混凝土塊在箱梁內(nèi)將會(huì)被用作壓載物. 除此之外,設(shè)計(jì)者已經(jīng)考慮在箱梁內(nèi)預(yù)留允許添加后預(yù)應(yīng)力鋼絞線的空間。如此長(zhǎng)期的行為不被完全知道,因

43、此,主跨在使用期間可能下?lián)系目赡鼙仨毐豢紤]。道路的寬度是從在邊之上的人行橫道到在另一邊的7.5 m ,而且橋的總寬度是10.3 m.包括2 m寬度的人行橫道。 </p><p>  橋梁的上部結(jié)構(gòu)與內(nèi)空的雙薄壁墩固結(jié)在一起. 碼頭橋使用長(zhǎng)期預(yù)應(yīng)力鋼絞線,而且他們有固定腹板厚度和高度呈拋物線形變化的箱梁。</p><p>  臨時(shí)約束也被應(yīng)用到此座橋梁上。它們位于以每距主跨中心120米分段區(qū)

44、的前35米處.組成I形的軸,使用巖石錨的固結(jié)到地面,而后經(jīng)由預(yù)力鋼絞線連接到箱梁. 這些結(jié)構(gòu)目的在于支援懸桁而且避免在強(qiáng)烈的風(fēng)作用下扭轉(zhuǎn)。橋上部構(gòu)造施工完成而且主要的預(yù)應(yīng)力束被完全張拉后, 臨時(shí)約束將會(huì)被去除。 橋的位置,距北極圈大約100 km,氣候條件很差,意謂著建筑工作中間必須使用特別的措施. 除了在冬季明顯的需要提供照明之外,同樣地在低達(dá)-30攝氏度的低溫中混凝土的凝結(jié)也必須被克服. 橋梁建設(shè)時(shí)現(xiàn)澆混凝土有時(shí)達(dá)到 30攝氏度而且

45、框架必須被絕緣使混凝土保持溫度。通過電暖氣的電纜在早先施工結(jié)束前也被用在混凝土的加溫. </p><p>  Sundoya橋在 2000 年1月開始建筑,預(yù)期在9月份完工。 懸臂的建筑在去夏天開始和預(yù)定在四月完成. 直至 Bd& e發(fā)布消息的時(shí)候,計(jì)劃是在秋季通車.</p><p>  Sundoya橋(挪威)基本資料:</p><p>  客戶: Sta

46、tens Vegvesen</p><p>  承包商: AF Sundoybrua(As Anlegg,NCC 建筑) </p><p>  顧問: Ing Aas-Jakobsen 博士</p><p>  業(yè)主: Boarch Arkitekter </p><p>  ——原文摘自《Bridge(design&engineer

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