'Smart repair' strategies using advanced metrology for enhanced structural health monitoring

我们目前的大部分基础设施都是用混凝土等现代材料建造的，已经或将需要大量的维修，在使用中——通常是在其设计寿命相对较短的一段时间之后，或者是为了延长寿命和减少“新建”的成本。目前，仅在英国，每年就有大约6亿英镑用于混凝土基础设施的维修和维护，这个数字在发达国家是许多倍。可维护性和增强的全寿命性能对于有效使用至关重要，对这些结构进行长期监测对于确保结构的全部功能，最大限度地减少对公众的风险和物有所值是非常宝贵的。此外，混凝土基础设施有一个明确的未来：具有长使用寿命的轻质材料的进步被视为可持续发展的必要条件，例如，使用高度耐用的轻质、低能耗混凝土，可用于新型和预制产品，并在其中结合先进的监控系统。然而，从我们的基础设施中实现最大价值的关键是更全面地了解需求和挑战，以便在现有结构的使用寿命期间更好地评估现有结构，以及使用新材料为未来创造更好的结构。在这两种情况下，都需要发展和广泛使用有效的监测系统，安装或改造这些系统以提供可靠和资料丰富的数据，并得到用户社区和工业界的信任。因此，监测和评估修复策略的有效性，作为结构健康监测的一个关键方面，是本提案的目标。这在这个项目中是独一无二的，两个因素结合在一起，使之成为可能：桥梁的可用性，自桥梁搬迁到现在的位置以来，已经应用的损坏情况将被众所周知并密切记录（作为国家物理实验室工作的一部分），以及已经和将要应用于它的修复策略。在这个项目中，解决这个问题的方法是使用新的、校准的监测设备，在维修过程本身和随后的维修过程中，在这两种情况下，都允许对桥梁的修复效果进行定量监测，因此这项工作对国家物理实验室目前的研究是非常补充和增加价值的。传统的SHM提供了一种评估，使大型工程资产的所有者能够更准确地安排维护计划，并可以对可能的结构故障进行早期预警。在这个项目中提出的系统类型将提供潜在问题的早期预警，并有助于更好地规划维护和维修：这里的建议将允许确定，监测和评估维修策略。因此，总体目标是获得更好的信息，以预测可能发生故障的可能性、修复的需要、修复的有效性，从而预测桥梁等结构的可能寿命。这承认了对预测系统的广泛工业需求，该系统可以监测结构并告知资产持有人其健康状态，包括其物理结构和化学变化，其中结构类型可以包括桥梁，建筑物，发电厂，飞机，化工厂等。即使只是考虑到桥梁的情况，一个简单的结构健康状况的明确指示将提供巨大的经济效益，因为仅在英国就有超过10,000座桥梁，每座价值超过100万英镑。提供有效的维修，从而更便宜的维护和更低的运行成本将是显著的效益。

Much of our current infrastructure, built of modern materials such as concrete, has or will require extensive repair, in service - often after even a relatively short period of its design life or to extend that life and reduce the costs on 'new build'. Currently an estimated ~600M is spent annually on the repair and maintenance of concrete infrastructure in the UK alone, a figure that is multiplied many times across the developed nations. Serviceability and enhanced whole life performance are critical to effective use and the long-term monitoring of such structures is invaluable to ensure full structural capability, to minimize risk to the public and give value for money. Further, there is a clear future for concrete infrastructure: the advancement of lightweight materials with a long service life is seen as essential to sustainable development, for example using highly durable lightweight, low energy concrete which can be used in a novel and pre-cast products and incorporating within it advanced monitoring systems. However, critical to achieving the maximum value from our infrastructure is a fuller understanding of the needs and challenges of allowing for better assessment of existing structures during their service lifetime as well as the creation of better structures for the future, using new materials. In both cases effective monitoring systems, installed or retrofitted and used to give reliable and informative data, having the confidence of the user community and industry, need to be developed and used widely. Thus monitoring and evaluation of the efficacy of repair strategies, as a key aspect of structural health monitoring, is the target of this proposal. This is made possible, uniquely in this project, by two factors coming together - the availability of a bridge where the damage conditions that have been applied since the bridge was moved to its present site will be well known and closely documented (as part of work done by NPL), as are the repair strategies that have been and will be applied to it. Addressing this in this project is the use of new, calibrated monitoring devices applied both during the repair procedure itself and subsequently, in both cases to allow the effects of the repair on the bridge to be monitored quantitatively and the work is thus very complementary to and adds value to research currently at NPL. Conventional SHM provides an assessment which allows the owners of large engineering assets to schedule maintenance more accurately, and can give an early warning of possible structural failure. The sort of system proposed in this project will provide early warning of potential problems and help in the better planning of maintenance and repair: the proposal herein will allow the repair strategies to be determined, monitored and evaluated. The overall aim is thus for better information to predict the likely potential for failure, the need for repair, the efficacy of the repair and thus the likely lifetime of a structure such as a bridge. This recognizes the wide industrial need for predictive systems that can monitor structures and inform the asset holder on its state of health, both in terms of its physical structure and chemical changes, where the type of structure could include bridges, buildings, power plant, aircraft, chemical plant etc. Even just considering the situation with bridges, a simple clear indication of the structure's health will provide substantial economic benefits since there are over 10,000 bridges worth more than 1M each in the UK alone - offering effective repair and thus cheaper maintenance and lower running costs would thus be of significant benefit.