桥梁专业外文翻译--欧洲桥梁研究.docx

附 录Bridge research in EuropeA brief outline is given of the development of the European Union, together with the research platform in Europe. The special case of post-tensioned bridges in the UK is discussed. In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio: relating to the identification of voids in post-tensioned concrete bridges using digital impulse radar. IntroductionThe challenge in any research arena is to harness the findings of different research groups to identify a coherent mass of data, which enables research and practice to be better focused. A particular challenge exists with respect to Europe where language barriers are inevitably very significant. The European Community was formed in the 1960s based upon a political will within continental Europe to avoid the European civil wars, which developed into World War 2 from 1939 to 1945. The strong political motivation formed the original community of which Britain was not a member. Many of the continental countries saw Britains interest as being purely economic. The 1970s saw Britain joining what was then the European Economic Community (EEC) and the 1990s has seen the widening of the community to a European Union, EU, with certain political goals together with the objective of a common European currency. Notwithstanding these financial and political developments, civil engineering and bridge engineering in particular have found great difficulty in forming any kind of common thread. Indeed the educational systems for University training are quite different between Britain and the European continental countries. The formation of the EU funding schemes e.g. Socrates, Brite Euram and other programs have helped significantly. The Socrates scheme is based upon the exchange of students between Universities in different member states. The Brite Euram scheme has involved technical research grants given to consortia of academics and industrial partners within a number of the states a Brite Euram bid would normally be led by an industrialist.In terms of dissemination of knowledge, two quite different strands appear to have emerged. The UK and the USA have concentrated primarily upon disseminating basic research in refereed journal publications: ASCE, ICE and other journals. Whereas the continental Europeans have frequently disseminated basic research at conferences where the circulation of the proceedings is restricted.Additionally, language barriers have proved to be very difficult to break down. In countries where English is a strong second language there has been enthusiastic participation in international conferences based within continental Europe e.g. Germany, Italy, Belgium, The Netherlands and Switzerland. However, countries where English is not a strong second language have been hesitant participants e.g. France.Post-tensioned concrete rail bridge analysisOve Arup and Partners carried out an inspection and assessment of the superstructure of a 160 m long post-tensioned, segmental railway bridge in Manchester to determine its load-carrying capacity prior to a transfer of ownership, for use in the Metrolink light rail system.Particular attention was paid to the integrity of its post-tensioned steel elements. Physical inspection, non-destructive radar testing and other exploratory methods were used to investigate for possible weaknesses in the bridge.Since the sudden collapse of Ynys-y-Gwas Bridge in Wales, UK in 1985, there has been concern about the long-term integrity of segmental, post-tensioned concrete bridges which may be prone to brittle failure without warning. The corrosion protection of the post-tensioned steel cables, where they pass through joints between the segments, has been identified as a major factor affecting the long-term durability and consequent strength of this type of bridge. The identification of voids in grouted tendon ducts at vulnerable positions is recognized as an important step in the detection of such corrosion.Description of bridgeGeneral arrangementBesses o th Barn Bridge is a 160 m long, three span, segmental, post-tensioned concrete railway bridge built in 1969. The main span of 90 m crosses over both the M62 motorway and A665 Bury to Prestwick Road. Minimum headroom is 5.18 m from the A665 and the M62 is cleared by approx 12.5 m.The superstructure consists of a central hollow trapezoidal concrete box section 6.7 m high and 4 m wide. The majority of the south and central spans are constructed using 1.27 m long pre-cast concrete trapezoidal box units, post-tensioned together. This box section supports the in site concrete transverse cantilever slabs at bottom flange level, which carry the rail tracks and ballast.The center and south span sections are of post-tensioned construction. These post-tensioned sections have five types of pre-stressing:1. Longitudinal tendons in grouted ducts within the top and bottom flanges.2. Longitudinal internal draped tendons located alongside the webs. These are deflected at internal diaphragm positions and are encased in in site concrete.3. Longitudinal macalloy bars in the transverse cantilever slabs in the central span .4. Vertical macalloy bars in the 229 mm wide webs to enhance shear capacity.5. Transverse macalloy bars through the bottom flange to support the transverse cantilever slabs.Segmental constructionThe pre-cast segmental system of construction used for the south and center span sections was an alternative method proposed by the contractor. Current thinking suggests that such a form of construction can lead to brittle failure of the entire structure without warning due to corrosion of tendons across a construction joint，The original design concept had been for in site concrete construction.Inspection and assessmentInspectionInspection work was undertaken in a number of phases and was linked with the testing required for the structure. The initial inspections recorded a number of visible problems including:1、 Defective waterproofing on the exposed surface of the top flange.2、 Water trapped in the internal space of the hollow box with depths up to 300 mm.3、 Various drainage problems at joints and abutments.4、 Longitudinal cracking of the exposed soffit of the central span.5、 Longitudinal cracking on sides of the top flange of the pre-stressed sections.6、 Widespread sapling on some in site concrete surfaces with exposed rusting reinforcement.AssessmentThe subject of an earlier paper, the objectives of the assessment were:1、 Estimate the present load-carrying capacity.2、 Identify any structural deficiencies in the original design.3、 Determine reasons for existing problems identified by the inspection.Conclusion to the inspection and assessmentFollowing the inspection and the analytical assessment one major element of doubt still existed. This concerned the condition of the embedded pre-stressing wires, strands, cables or bars. For the purpose of structural analysis these elements、had been assumed to be sound. However, due to the very high forces involved,、a risk to the structure, caused by corrosion to these primary elements, was identified. The initial recommendations which completed the first phase of the assessment were:1. Carry out detailed material testing to determine the condition of hidden structural elements, in particularthe grouted post-tensioned steel cables.2. Conduct concrete durability tests.3. Undertake repairs to defective waterproofing and surface defects in concrete.欧洲桥梁研究在欧洲，一个共同研究的平台随着欧盟的发展诞生了。为了举例说明欧洲的研究方法已经被这种方式所替代，一个典型的案例就是有关英国后张法桥梁被讨论的事，爱丁堡大学给出了这个关于用数字化脉冲雷达鉴定后张法混凝土桥梁孔隙的资源互补的案例。引言利用各研究团体的研究成果去验证大量相关论据是所有研究领域所面临的挑战，这是为了能使研究和实践更好地结合，具有针对性。此外，在欧洲，不容忽视的语言壁垒也是一个巨大的障碍,为了避免再次爆发类似于从1939年至1945的第二次世界大战似的的欧洲内战，欧洲国家有了一个共同的政治目的，成立于20世纪60年代的欧共体便是基于这一目的。它的成立带有很强的政治动机，但英国并非这一组织的成员，因为很多的欧洲国家视英国的利益为单纯的经济利益，直到70年代，英国才加入由欧共体转化而来的欧洲经济共同体。到90年代，欧洲经济共同体扩展为欧洲国家联盟，而此时的欧盟既有共同的政治目标又有建立欧洲共同的货币体系的经济目标。随着经济和政治的发展，土木工程，尤其是桥梁工程至今没能形成某种统一阵线。这缘于英国和其他的欧洲国家迥异的大学教育培养体制，欧洲基金计划如苏格拉底计划、大不列颠（英国）欧洲计划等等。对改变这种局面发挥了独特的作用，苏格拉底计划是以各成员国内互派学生学习为基础，而英国欧洲计划主要是给予一些国家的学术机构和工业伙伴以科研援助；它通常是由一个工业国家牵头。关于知识的传播，目前似乎已出现了2种非常不同的方式、英美主要集中于在相关期刊出版物上发表首要的研究成果，例如ASCE、LCE及其它期刊，而欧洲内陆国家主要集中于在专门会议上展示其重要的研究成果，后者存在着局限性，新的研究成果的发布受到了限制。另外，语言也是难以逾越的障碍，那些以英语作为强势外语的欧洲内陆国家积极参与各种国际会议，如德国、意大利、比利时、以及荷兰和瑞士。然而，那些不以英语为强势外语的欧洲国家对国际会议的参与并不积极，比如法国。后张法混凝土铁路桥研究欧而阿朴和他的合作者对曼彻斯特的一座长160M的后张法分段预制施工建造的铁路桥的上部结构的长期稳定性进行了检测和评估，这种技术已被运用于城市轻轨系统。特别需要关注的是后张力法施工的桥梁的完整性。物理检查、非损伤雷达检测及其它的研究方法均已被用来去调查桥梁中潜在的缺陷。自从1985年2月1日英国威尔士地区的一座名叫Ynys-y-Gwas桥梁突然坍塌以来。