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Debris Effects on BRIdge resiliencE and Flooding

碎片对桥梁弹性和洪水的影响

基本信息

批准号：
NE/R009015/1
负责人：
Gustavo De Almeida
金额：
$ 9.2万
依托单位：
University of Southampton
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FR009015%2F1
关键词：
Debris Effects BRIdge resiliencE Flooding

项目摘要

Engineers, scientists and the lay public alike have long been troubled by the complex and sometimes catastrophic interplay between rivers and bridges. River bridges have their foundations built on river beds, which can undergo significant scour during flood events. The term scour denotes the erosion of the river bed soil that occurs as a result of fast and turbulent water flowing close to the bridge pier. When the descent of the bed caused by scour is too deep, the foundations may be undermined or simply incapable of sustaining the bridge, in which case the whole structure can be severely damaged or even collapse. Most bridge collapses that occur throughout the world are caused by this phenomenon. A further complication that occurs in rivers that transport large amounts of floating material (tree trunks, branches or human debris, often called 'debris') is the accumulation of this material at bridge piers forming a jam. These debris jams alter the flow by directing the velocity towards the bed, which exacerbates scour and increases the risk of bridge collapse. Debris jams also produce large forces on the pier, further contributing to the prospects of bridge failure. A wide body of research now acknowledges that debris ranks high among the causes of bridge failures around the world, being responsible for approximately 30% of bridge failures in the UK and the US. In addition to the threats posed to bridge safety, the blockage of bridges by debris leads to increased upstream water levels that can result in flooding of adjacent areas. As many bridges are located in urban areas-where costly assets are located and more people are exposed- debris jams can considerably increase the risk of flooding. The above problems are expected to become more frequent in the future as a result of i) increased river flows due to climate change, ii) increased number of bridges and population exposed to flooding that will follow from socio-economic growth. Recent events highlight the urgency for improved risk assessment and mitigation methods to build up the resilience of these key pieces of infrastructure. For example, during the 2009 and 2015 Cumbrian floods respectively 244 and 80 bridges were either damaged or lost.The project partners, Network Rail and the Environment Agency, are directly affected by the issues above. Network Rail owns more than 8,000 bridges near or close to waterways. The Environment Agency owns approximately 2,000 bridges over water courses. In addition, the Environment Agency is responsible for managing the risk of flooding from main rivers, estuaries and the sea. Until recently, the tools that were available to the project partners (as well as other stakeholders directly affected by these issues) to assess debris-induced risk were not based on strong science and were considerably limited. A recent assessment of these methods has demonstrated serious inconsistencies and inaccuracies, therefore rendering them inadequate for the management of risk of important infrastructure systems. Recent research conducted at University of Southampton has delivered a step-change in our understanding of how debris jams at bridge piers grow. These new results and predictive capabilities now pave the way for significant improvements in the way that the project partners assess risk, and therefore to a more effective use of resources to mitigate the risk of failure of critical infrastructures.The overarching aim of the project is to bridge the gap between this recent research and the practical needs of the project partners by translating the previous research into a robust, accurate and user-oriented methodology to assess the effects of debris jams on bridge resilience and flooding. The outcomes of the project will enable the project partners to take more informed decisions on how to prioritise investments to build up the resilience of critical infrastructure.

工程师、科学家和普通公众长期以来一直为河流和桥梁之间复杂的、有时甚至是灾难性的相互作用所困扰。河桥的基础建在河床上，在洪水期间可能会遭受严重冲刷。冲刷一词是指由于靠近桥墩的快速而湍急的水流而发生的河床土壤侵蚀。当冲刷造成的河床下降过深时，地基可能会被破坏或根本无法支撑桥梁，在这种情况下，整个结构可能会受到严重破坏，甚至倒塌。世界各地发生的大多数桥梁倒塌都是由这种现象引起的。在运输大量漂浮物质（树干、树枝或人类残骸，通常称为“碎片”）的河流中发生的另一个复杂情况是这些物质在桥墩处堆积，形成堵塞。这些碎片堵塞通过将速度导向河床来改变流动，从而加剧冲刷并增加桥梁倒塌的风险。碎片堵塞还会对桥墩产生巨大的作用力，进一步加剧桥梁破坏的可能性。大量研究现已承认，碎片在世界各地桥梁失效的原因中名列前茅，在英国和美国，碎片约占桥梁失效的 30%。除了对桥梁安全构成威胁外，桥梁被碎片堵塞还会导致上游水位上升，从而导致邻近地区发生洪水。由于许多桥梁位于城市地区，那里有昂贵的资产，而且有更多的人暴露在危险之中，碎片堵塞会大大增加洪水的风险。由于 i) 由于气候变化导致河流流量增加，ii) 社会经济增长导致遭受洪水影响的桥梁数量和人口增加，预计上述问题在未来将变得更加频繁。最近发生的事件凸显了改进风险评估和缓解方法的紧迫性，以增强这些关键基础设施的弹性。例如，在 2009 年和 2015 年坎布里亚洪水期间，分别有 244 座和 80 座桥梁被损坏或丢失。项目合作伙伴英国铁路网和环境局直接受到上述问题的影响。 Network Rail 拥有 8,000 多座靠近水道的桥梁。环境署拥有大约 2,000 座跨河道桥梁。此外，环境局还负责管理主要河流、河口和海洋的洪水风险。直到最近，项目合作伙伴（以及受这些问题直接影响的其他利益相关者）可用于评估碎片引发的风险的工具还没有基于可靠的科学依据，而且相当有限。最近对这些方法的评估表明存在严重的不一致和不准确之处，因此它们不足以管理重要基础设施系统的风险。南安普顿大学最近进行的研究使我们对桥墩碎片堵塞如何发展的理解发生了重大变化。这些新的结果和预测能力现在为项目合作伙伴评估风险的方式的重大改进铺平了道路，从而更有效地利用资源来减轻关键基础设施的故障风险。该项目的总体目标是通过将之前的研究转化为稳健、准确和面向用户的方法来评估碎片堵塞对桥梁的影响，从而弥合最近的研究与项目合作伙伴的实际需求之间的差距。复原力和洪水。该项目的成果将使项目合作伙伴能够就如何确定投资优先顺序以增强关键基础设施的弹性做出更明智的决策。