Assessing the Performance of Masonry Railway Viaducts in the UK by Detecting Hidden Defects and Geometric Features =Structural Engineering

通过检测隐藏缺陷和几何特征来评估英国砖石铁路高架桥的性能=结构工程

• 批准号: 2184142
• 金额: --
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2184142
• 关键词: Assessing; Performance; Masonry; Railway; Viaducts

Masonry railway viaducts in the UK have at large exceeded the modern-day design life of 120 years, for which they were not designed for. More importantly, it must be highlighted that masonry arches were designed (largely) from empirical methods such as Molesworth's formula (small arches) and the 18th century revolutionary method developed by Perronet for multi-span structures (Robinson and Kapoor, 2009). As such, the verification of structural capability for modern day use is a major challenge, particularly considering the lack of as-built information for these structures, changes in loading, poor records of maintenance repairs and challenges with assessing the impact of various defects on structural performance.The key to assessing the structural capability and residual life of masonry railway viaducts begins with verification of the geometric features and defects, including hidden defects. The collection of such data can be a timely process, with numerous access restrictions. This is exacerbated by the occupancy of arches within railway viaducts, which are known as 'tenanted arches'. Network Rail currently have 10425 tenanted arches across their portfolio, many of which include cladding panels, preventing direct visibility of the soffit and piers of arches. In order to view these defects, examiners must arrange access with tenants, remove cladding panels (usually fixed with anchors) then fix the panels back on. It is important to note that the arches were not designed for these cladding fixtures and loads, as well as lighting fixtures and other services suspended from the arch soffit. Many of these arches include shafts, which have been capped or plugged with concrete, which adds another complexity to the global behaviour of the structure.In order to reduce the risk to the operational railway and to the tenants within these structures, there is a need to improve the methods to obtain asset condition data and model the structural behaviour more accurately with the data collected. Non-Destructive Testing (NDT) methods can aid this process and prevent the need to remove cladding panels and also to verify geometric features at track level, via the use of NDT tools on Unmanned Aerial Systems (UAS). This will provide additional benefits such as cost savings for maintenance, improved compliance with safety standards, better relationships with tenants and a more accurate understanding of the residual service life of the structures. The significance of this issue was highlighted when Network Rail released a challenge statement to the public to address the challenges they currently face. The main aim of this study is to determine the viability of using NDT/NDE techniques on Masonry Railway Viaducts in the UK, and to utilise the data captured to improve the capability assessment of the viaducts. The focus of the study will be to capture hidden defects within tenanted arches, where the arch soffit is covered with cladding panels, as well as geometric features (distortions, voids, discontinuities, ring separation etc.) at track level, by deploying UAS equipped with various NDT/NDE equipment. Mohammed Al-SHarif am currently sitting on the Steering Panel for a CIRIA project, on behalf of Network Rail, to develop a best practice guidance document for NDE of Civil Structures. The outcome of this CIRIA project will support the PhD study and enable knowledge transfer between academia and industry.

英国的马斯喀特铁路高架桥已经超过了120年的现代设计寿命，而这不是它们的设计寿命。更重要的是，必须强调的是，圬工拱的设计（主要）来自经验方法，如莫尔斯沃思公式（小拱）和Perronet为多跨结构开发的18世纪世纪革命性方法（罗宾逊和Kapoor，2009）。因此，验证现代使用的结构能力是一个重大挑战，特别是考虑到这些结构缺乏竣工信息，荷载变化，评估砖石铁路高架桥的结构能力和剩余寿命的关键是从验证几何特征开始，包括隐藏的缺陷。收集这类数据可能是一个及时的过程，有许多访问限制。铁路高架桥内的拱形结构被称为“租户拱形结构”，这加剧了这种情况。Network Rail目前在其产品组合中有10425个租户拱门，其中许多包括覆层面板，防止直接看到拱腹和桥墩。为了查看这些缺陷，检查人员必须安排与租户接触，拆除覆面面板（通常用锚固定），然后将面板重新固定。重要的是要注意，拱门的设计不适合这些覆面设备和负载，以及照明设备和其他从拱腹悬挂的服务。许多拱门都包括竖井，竖井已经被混凝土覆盖或堵塞，这给结构的整体行为增加了另一个复杂性。为了降低运营铁路和这些结构内租户的风险，需要改进获取资产状况数据的方法，并利用收集的数据更准确地对结构行为进行建模。无损检测（NDT）方法可以帮助这一过程，并防止需要删除包覆板，并通过在无人机系统（UAS）上使用NDT工具来验证轨道水平的几何特征。这将带来额外的好处，例如节省维修费用，更好地遵守安全标准，改善与租户的关系，以及更准确地了解结构的剩余使用寿命。当网络铁路向公众发布挑战声明以应对他们目前面临的挑战时，这个问题的重要性得到了强调。本研究的主要目的是确定使用无损检测/无损评价技术的可行性在英国的马斯喀特铁路高架桥，并利用捕获的数据，以提高高架桥的能力评估。研究的重点将是捕捉隐藏的缺陷，在租用拱，拱腹覆盖着覆板，以及几何特征（扭曲，空隙，不连续，环分离等）。在轨道水平，通过部署配备各种NDT/NDE设备的UAS。Mohammed Al-Sharif目前代表Network Rail担任CIRIA项目的指导委员会成员，为土木结构的NDE制定最佳实践指导文件。该CIRIA项目的成果将支持博士研究，并实现学术界和工业界之间的知识转移。