Steel railway bridges as a legacy of high modernity - Foundations for a holistic decision making between repair and renewal

根据“Verkehrswende”日益增长的需求升级德国铁路公司的铁路网是未来十年德国基础设施发展中最重要的项目。现代化工程还直接影响到自19世纪末以来建造的大量钢铁路桥，这些桥在此期间往往达到了其“名义”寿命。特别是在纪念物部门，关于更新或修复和加强的决定通常是根据比较评估矩阵作出的，到目前为止几乎完全是根据技术和经济标准作出的。另一方面，没有考虑到文化或生态标准，或者最多只是一次性计入。一方面，缺乏适当审议后一种标准的可靠基础；另一方面，技术经济领域的定量评价难以与更为定性的评价相比，尤其是建筑文化领域。在此背景下，该项目旨在为钢桥的整体评估提供可靠的方法基础，其中所有提到的四个标准都得到充分和可比的考虑。重点不是对现有桥梁的评估，而是对其使用历史的一个中心点——在某个阶段维护或更新它们的决定。关键的不是“产品”结构，而是在这些基本选项之间做出决定的过程。在技术、经济、生态、建筑文化四个维度上，首先形成可比的评价关键字，然后将它们组合成一个整体评价体系。第一个重点是通过在内容和概念方面扩展现有的评估方法，规范和阐述生态和建筑文化标准。第二个重点是比较拟订一个尽可能有效的全面评价制度。为此将开发两种变体，可以在DB Netz AG的桥梁建设项目案例研究的第三个重点中进行测试，比较和改进。所获得的知识使我们有可能执行一个有充分根据的评价制度，并在此基础上制定实际例行活动中的适当行动战略。该项目是由BTU Cottbus-Senftenberg建筑史荣誉教授（Werner Lorenz）和伍珀塔尔大学环境兼容基础设施规划系（Felix Huber）合作进行的。

The upgrade of Deutsche Bahn's rail network according to the growing demands of the "Verkehrswende" is the most important project of German infrastructure development in the coming decade. The modernization project also directly affects the still large number of steel railway bridges built since the end of the 19th century, which in the meantime have often reached their “nominal” lifespan. Particularly in the monument sector, the decision on renewal or repair and strengthening is usually made on the basis of comparative assessment matrices, which so far have almost exclusively been based on technical and economic criteria. Cultural or ecological criteria, on the other hand, are not taken into account or are at most included as a lump sum. On the one hand, there is a lack of reliable foundations for an appropriate consideration of the latter criteria; on the other hand, the quantitatively fixable evaluations in the technical and economic fields can hardly be compared with the more qualitative evaluations, especially in the field of building culture.Against this background, the project aims to provide the basis for a robust methodology for the holistic assessment of steel bridges, in which all four criteria mentioned are adequately and comparably taken into account. The focus is not on the evaluation of existing bridges, but on a central point in their use history - the decision to maintain or renew them at a certain stage. It is not the "product" construction that is at stake, but the process of making the decision between these basic options.For the dimensions of technology, economy, ecology and building culture, comparable evaluation keys are first developed, which are then combined in an overall evaluation system. The first focus is on the specification and elaboration of ecological and building culture criteria by extending existing evaluation approaches in terms of content and concept. A second focal point is the comparative formulation of an overall evaluation system that is as efficient as possible. Two variants will be developed for this, which can be tested, compared and sharpened in the third focus in case studies on bridge construction projects of DB Netz AG. The knowledge gained opens up the possibility of implementing a well-founded evaluation system and, building on this, appropriate action strategies in practical routines.The project is carried out in cooperation between the honorary professorship for Construction History at the BTU Cottbus-Senftenberg (Werner Lorenz) and the department of Environmentally Compatible Infrastructure Planning at the University of Wuppertal (Felix Huber).