Methods for assessment existing structures based on measured stresses with a focus on analysis of load combinations, model uncertainties and expansion at the level of the load-bearing system

基于测量应力评估现有结构的方法，重点分析荷载组合、模型不确定性和承载系统层面的扩展

• 批准号: 280831118
• 负责人: Professor Dr.-Ing. Karsten Geißler
• 金额: --
• 依托单位: Fachgebiet Entwerfen und Konstruieren - Stahlbau
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/280831118?language=en
• 关键词: Methods; assessment; existing; structures; based

Due to the large number of old bridges as well as the increase of traffic loads, especially by road bridges, the realistic assessment of existing structures becomes more important. Existing structures are characterized by the possibility of obtaining additional information about actual stresses and their load capacity. Therefore, structural measurements are (or monitoring if performed over a longer period) being used increasingly to assess the condition of existing bridges in a more realistic way. Meanwhile, the possibilities of using structural measurements or monitoring are versatile and the technical conditions for a safe implementation are given. However, it still has to be clarified, to which extent the additional information obtained by structural measurements and monitoring are to be taken into account within the structural safety concept. This research proposal aims to develop the fundamentals of structural reliability in order to integrate more detailed, measurement-based information about actual stresses into the safety concept of assessment of existing bridges. For this purpose, generalized theoretical reliability methods will be developed for assessing existing structures using limit state functions. Furthermore, based on systematical evaluation of these decisive limit state functions for typical bridge structures, generalized approaches to deriving the safety factors for measurement-based structural assessment will be introduced. This concerns ultimate limit state with recording extreme values as well as fatigue limit state with recording loading spectrums. Moreover methods will be developed to determine measurement-based safety factors for several time-dependent loads. These systematical investigations will be done using the example of bridges because firstly, the developed methods are transferrable to the problems of the general structural engineering (by means of stresses determined with less effort usually). Secondly, a direct contribution to the theoretical fundamentals can be given for solving the current and socially relevant problem of the realistic assessment of bridges.

由于旧桥梁数量大量以及交通负荷的增加，尤其是道路桥梁，对现有结构的现实评估变得更加重要。现有结构的特征是获得有关实际应力及其负载能力的其他信息的可能性。因此，结构测量是（如果在更长的时间内执行）被越来越多地用于以更现实的方式评估现有桥梁的状况。同时，使用结构测量或监视的可能性是多功能的，并提供了安全实施的技术条件。但是，仍然必须澄清一下，在结构安全概念中应考虑通过结构测量和监测获得的其他信息。该研究建议旨在开发结构可靠性的基本原理，以将有关实际压力的更详细，基于测量的信息整合到现有桥梁评估的安全概念中。为此，将开发一般的理论可靠性方法，用于使用极限状态功能评估现有结构。此外，基于对这些决定性极限状态功能的系统评估，将引入基于测量的结构评估的安全因素的广义方法。这涉及最终限制状态，即记录极端值以及疲劳限制状态，并具有记录载荷频谱。此外，将开发方法来确定基于测量的安全因子的几个时间依赖性负载。这些系统的研究将以桥梁的示例进行，因为首先，开发的方法可以转移到一般结构工程的问题上（通过通常以减少努力来确定的压力）。其次，可以为理论基础做出直接贡献，以解决桥梁现实评估的当前和社会相关问题。