桥梁工程专业毕业论文外文翻译.doc

外文翻译Quick fix: replacement of an old wooden bridge in St Petersburg was completed earlier this year.Rising traffic levels and development demands led to an old tramway bridge being rebuilt as a cable-stayed crossing in the Russian city of St Petersburg. The new Lazarevsky Bridge across the Malaya Nevka was opened to traffic earlier this year, replacing an old wooden structure which was built for trams but recently had only been used by pedestrians. The bridge is located in Petrograd district and connects Krestovsky and Petrogradsky Islands along Pionerskaya and Sportivnaya Streets, both of which are importanat links for local traffic. When it was built in 1949, the crossing was called the Koltovsky Bridge, after the adjacent Malaya Nevka river embankment. But in 1952, it was renamed to commemorate the legendary Russian admiral Mikhail Lazarev. The embankment and the bridge were redesignated the Admiral Lazarev Embankment and Lazarevsky Bridge respectively. Built to the design of engineer VV Blazhevich, the original bridge had 11 spans, the central one being a single-leaf drawspan. It was originally designed for trams and was the only tramway bridge in the city at that time. Its total length was 141m and its width was 11m, the deck consisting of metal baulks and wooden plank flooring. The timber post piers rested on piled foundations of steel pipes. But in 2002 the tramway was closed and since then, the bridge has only been used by pedestrians. Its location meant that Lazarevsky Bridge served the western part of the city-the Petrograd districts including Krestovsky island. All the road traffic to Krestovsky island used the main Krestovsky Bridge which as a consequence was considerably overloaded. Since the Lazarevsky Bridge carried no vehicular traffic it was not considered part of the road network of the district. But plans to build a new stadium at the Seaside Victory Park on Krestovsky Island just 3km from the bridge site meant that a reliable transport connection to the rest of the city was required. The local authority decided that reconstruction of the Lazarevsky Bridge was the best way to provide this. The size of new bridge was determined based on the predicted traffic levels, taking into account the prospective development of the district. According to the forecast, the annual average daily traffic intensity on Lazarevsky Bridge will rise to 16,000 vehicles per day by 2025. Peak loads occur during major sporting events at the stadium when the bridge will be required to help relieve the area of traffic within one hour. This traffic flow includes 4,500 to 5,000 cars, so even if the Petrovsky Bridge were to be rebuilt, the Lazarevsky Bridge needed two lanes of traffic in both directions in order to do this. Taking into consideration the fact that the timber structures of the bridge had been in use for more than 55 years, if the bridge reconstruction had been restricted to the widening and strengthening of the existing superstructure and piers, it would not have ensured the longevity of the fixed bridge and might have led to high operation costs. Another consideration was that the appearance of a multi-span structure with bulky piers would not have fitted into the architectural style that is emerging with construction of modern buildings on Krestovsky Island and the adjacent embankments. As a result, the decision was taken to completely demolish the existing bridge and replace it with a new structure on the same alignment. As part of the project, some of Sportivnaya Street on the right bank had to be widened, and improvement of the adjacent area was also included. The history of the project dates back more than a decade to 1998, when JSC Institute Strojproect won the tender to carry out a feasibility study into the reconstruction of Lazarevsky Bridge and its approaches. Even at this time, the architect Igor Serebrennikov had developed an original architectural concept of the bridge which involved use of a cable-stayed system. This concept was approved by the citys committee for development but financial problems meant that the design was suspended for seven years before it resumed. In 2003, the project was included in the target programme of design and survey works, and the tender for design development was officially announced. Again these works were awarded to JSC Institute Strojproect. The reconstruction design was completed in 2007 and was received positively by the State Expert Review Board; construction began at the end of that year. The structural concept of the bridge was approved based on the comparison of technical and economical options. One of the main restrictions was the strict limitation on the superstructure construction depth. On the one hand, it was limited by the need to maintain underbridge clearance for navigation, while on the other hand the deck level was governed by the height of Admiral Lazarev Embankment, which could not be raised, according to the requirements of the committee for protection of monuments. To meet these almost incompatible conditions it was necessary to make the longitudinal profile of the deck with a vertical curve of radius 1,000m, a radius which is allowable only for very constrained conditions. But even with this minimum vertical curve radius, the limitation for the deck construction depth remained fairly strict-it had to be 1.4m at the maximum. This condition could be met either by a classic five-span continuous beam scheme or by a cable-stayed system. The costs of both options are practically the same but the cable-stayed option was preferred as it was considered more attractive from the architectural point of view. Another benefit was that it would take less time for construction as there was no need for intermediate piers to be built in the river bed. The unconventional appearance of the structure, particularly the shape of the tower and its asymmetric arrangement with its single span, put demands on the design abilities of the engineers from JSC Institute Strojproect, requiring them to cope with non-standard problems. One such problem was the need to provide the required rigidity to the deck while at the same time minimising its weight in order to decrease the moments in the tower elements and balance the system. Hence a single-span cable-stayed bridge with steel deck, orthotropic carriageway slab and a steel tower was selected for construction. The deck is supported by two rows of stays, with five stays in each row. The cable stays pass through the tower and are anchored in the reinforced concrete slab of the counterweight which is located beyond the bridge abutment on Krestovsky Island. The front arch of the tower, which is inclined towards the riverbed, carries the dead anchorages by which means the cable stays and backstays are secured. Tensioning of both sets of cables was carried out by means of active anchors located at the deck and in the counterweight slab. To minimise the total width of the deck, the anchorages are removed to the front surfaces of the main beams. The optimum force distribution in the tower elements was obtained by means of the arch shape that became sharper and elongated in the transverse section of the bridge. The deck consists of a system of longitudinal and transverse H-beams connected via the orthotropic slab with its U-shape stiffeners. The anchorages are located along the transverse beams. At the tower, the deck is rigidly fixed and at pier one it rests on Maurer spherical bearings. The steel part of the deck is made of low-alloy steel grade 10 and 15 and the tower of steel grade 10 (400MPa). The cable stays are VSL standard monostrands and each one is made up of from 50 to 73 strands. The total length of strand used in the bridge is about 31km. Meanwhile the bridge deck pavement consists of two layers of asphalt/concrete 40mm and 50mm placed over the Technoelastomost-S membrane waterproofing layer. The pier foundations are formed of high pile caps resting on bored piles driven deep into the bearing stratum of firm clay. Above the foundation top, the piers are made of cast in situ concrete and faced with granite. Construction was carried out by Mostootryad No 75, a branch of OAO Mostotrest No 6, while the steel deck structure was manufactured by JSC Zavod Metallokonstruktsiy and the steel tower structure was manufactured by NPO Mostovik. For development of the detail design the specialists of automation division of the Institute prepared complex 3-D models of the tower and cable stay anchorages in PRO-E software which were used for analysis and as a basis for the fabrication of the structures by NPO Mostovik. The use of this successful PRO-E modelling enabled the complicated tower structures to be manufactured within a relatively short time. Taking into consideration the constraints imposed on the bridge construction, JSC Institute Strojproect suggested some modifications to the detailed design. One such proposal was to replace the cable backstays of the tower with rigid ties made of low-alloy steel grade 10 which would be fixed rigidly at the tower arches and counterweight. Temporary supports would be installed under the deck anchorages These modifications allowed the erection of the back-stays to be considerably simplified, and would also eliminate the need to tension the backstays, cutting in half the time for the cable-stay installation. In addition it meant that the cable-stays supporting the deck could be tensioned in a single operation, once the asphalt and concrete pavement had been installed on the bridge. Analysis included successive tensioning of cable-stay pairs from the longest pair down to the shortest pair with the subsequent final tensioning of the two longest pairs. Apart from the forces, the vertical displacements of the deck at the breakaway points on the temporary supports had to be controlled. The actual tensioning works were carried out in compliance with the design solutions. The data on the forces and displacements at each stage were handed over by the general contractor to the designers, and if necessary, the required corrections were introduced to the design. On the whole, the calculated data showed a high correlation with the actual parameters. In fact it took the general contractor only 17 months to complete construction of all the works involved in the bridge construction. The new cable-stayed bridge has fitted harmoniously into the surrounding landscape. By avoiding placement of intermediate piers in the riverbed it was possible to open up views along the Malaya Nevka. The arch tower acts as a symbolic gateway to the island and stands out distinctly against its background of sky and trees. The architectural expressiveness of the bridge is determined by the general asymmetrical composition and the dynamic shape of the tower formed by two inclined arches, a light and gently-curved deck, and the elegant outline of the cable stay arrangement. At night time, the appearance of the bridge is highlighted by architectural lighting. Tatiana Gurevich is project manager and Yuri Krylov is head of the structural steel department at JSC Institute Strojproect桥梁的快速修复圣彼得堡一座旧木桥今年的更换工作在俄罗斯的圣彼得堡，崛起的交通水平和发展要求促使一个旧的电车轨道桥被改造为一个斜拉桥。新的Lazarevsky大桥横跨马来亚内芙卡，并与今年早些时候建成通车，取代了一座本来供有轨电车通行但是现在只供行人行走的旧木质桥。这座桥坐落于彼得格勒区，并且沿着Pionerskaya和Sportivnaya街道将Krestovsky和Petrogradsky群岛连接了起来，这两者都是当地的交通枢纽。它始建于1949年，当时被称为Koltovsky桥，相邻马来亚内芙卡河堤。但在1952年，为了纪念传说中的俄罗斯海军上将米哈伊尔拉扎列夫，路堤及桥梁被易名为拉扎列夫海军上将路堤和Lazarevsky桥。这座桥由VV Blazhevich工程师设计，最初桥有11跨，中央一个是单叶。它最初是设计用于电车，并且是当时该市唯一的一座电车轨道桥。总长度为141m，总宽度为11m，层面由金属和木质材料组成。木材支柱支撑的码头建在钢管桩基础上。但是在2002年时，电车轨道被关闭，从那时起，这座桥只供行人使用。这座桥梁的位置就意味着它服务这座城市的西部包括Krestovsky岛的彼得格勒区。所有到Krestovsky岛的车辆都用主要这个岛的Krestovsky桥，这自然导致该桥大大超载。由于Lazarevsky桥并没有承受车辆荷载，所以它不被认为是彼得格勒区的交通网络的一部分。但是，Krestovsky岛上计划在victory公园里兴建一个体育场，离海边仅有3公里，这意味着城市的其余部分需要一个可靠的连接方式。当地政府认为解决这个问题最好的办法就是重建Lazarevsky桥。新桥的规模取决于现有交通水平，并且考虑到了该地区未来的发展。据预测，到2025年，Lazarevsky桥的全年平均日交通量将上升至16000车次。车流高峰发生在体育场馆举行重大赛事时，此时该桥须能在一小时内纾缓这个地段的交通。这股交通流包括4,500至5,000辆车，所以即使Petrovsky桥能够重建，Lazarevsky桥也需要双向四车道来达到疏通效果。考虑到这座木质桥已经使用了55年以上，如果在限制上层建筑宽度和加强现有上层建筑的基础上重建，也许不能保证桥梁的寿命，而且会导致产生较高的运营成本。另外一个值得考虑的问题是，一个拥有庞大突堤的多跨桥的外观不会与现代建筑和邻近堤岸的风格相融合。因此，人们决定彻底拆除现存的桥梁，再在原来的位置上建造一座新的桥梁。作为项目的一部分，右岸Sportivnaya街道的一部分必须加宽，并且还要改善邻近的地区。这个项目的历史可以追溯到1998年，那是JSC研究所刚刚中标，它提出了一套对Lazarevsky桥进行重建的方法。即使在这个时候，建筑师伊戈尔谢列布连尼科夫曾经提出过一种关于桥梁原创性的建筑观念，其中就包括使用斜拉桥系统。这个概念曾经被市政府批准，但是由于财政问题，这个设计在重新恢复之前曾经被暂停了七年。2003年，该项目被列入目标工程和方案设计工作，开发设计招标正式公布。这项工作又一次被授予了JSC研究所。重建计划在2007年底完成并且被国家审查委员会积极地接收；建设工作就在当年年底开始。在进行技术可行性和经济适用性比较的基础上，大桥的结构概念获得了认可。一个主要的限制是桥梁上部结构高度的严格限制。一方面，为了通航，桥梁必须保持一定的桥下净空，另一方面，桥面高度又被拉扎列夫海军上将限制，为了保护文物 ，桥面高度不能提高。为了满足这些几乎是相互矛盾的条件，桥面纵向剖面的曲线半径只能为1000m，只有这样才能满足所有的条件。但是即使采用了这种最小的剖