Durability Testing and Reliability Analysis of Connections in Lightweight Metal Structures

在建筑和桥梁等民用基础设施的设计中，减少用户延误成本和长期环境影响等美学和可持续性考虑越来越多地促使设计师考虑使用轻质金属结构。在材料成本适度增加的情况下，通过使用更耐用的合金和轻型模块化解决方案，可以实现显著的效益，这些解决方案允许更长的使用寿命、更高的预制度、更低的运输和安装成本，并显著缩短建造时间。这些材料也特别适合于“为解构而设计”(DFD)，这是一个新兴的概念，它涉及在设计阶段仔细考虑，主要是通过材料选择和连接设计，在结构使用寿命结束时如何更容易地拆卸，以促进更高的重复利用率。为了确保在轻质金属结构提供的可持续性和社会效益方面实现最大潜力，需要进行基础研究，以便为这些结构开发更耐用和可靠的连接概念。*在此背景下，当前的提案描述了开创性的研究，旨在增加知识水平，并为以下连接类型开发改进的设计规则和性能特征：i)模块化金属结构中的抗滑螺栓连接，ii)缆索支撑结构中鞍座支撑处的缆索，以及iii)轻型铝桥面板中的搅拌摩擦焊接(FSW)节点。在每个项目中，研究生将使用类似的研究工具，包括：耐久性测试、有限元(FE)建模、非线性断裂力学以及风险和可靠性分析。这项研究将调查复杂的现象，专家们仍在努力完全理解和准确模拟这些现象，包括：腐蚀、磨损、微动疲劳和变幅(VA)载荷对疲劳行为的影响。计划中的实验将验证分析模型，这些模型将用于研究通过材料选择、几何设计和通过各种方法进行表面增强来改善连接性能的方法。*预计这项及时的研究将导致对连接行为的更广泛基本原理的更好理解，并提出新的和创新的连接概念，这些概念最终将被采纳为标准，并改变我们设计新建筑和桥梁的方式。通过这项研究培养的高素质人才(HQP)将受到加拿大建筑业的高度追捧，他们将担任领导角色，因为他们将获得耐久性评估、可靠性分析和可持续基础设施设计方面的专业知识。

In the design of civil infrastructure, such as buildings and bridges, aesthetics and sustainability considerations such as reducing user delay costs and long term environmental impacts are increasingly leading designers to consider the use of lightweight metal structures. With a modest increase in material cost, significant benefits can be realized through the use of more durable alloys and lightweight modular solutions that allow for longer service lives, a higher degree of prefabrication, reduced transportation and installation costs, and significantly reduced build times. These materials also lend themselves particularly well to “design for deconstruction” (DfD) – an emerging concept, which involves careful consideration at the design stage, largely through the material selection and connection design, of how a structure can be more easily taken apart at the end of its service life to facilitate higher rates of reuse. In order to ensure that the highest potential is achieved in terms of the sustainability and societal benefit offered by lightweight metal structures, fundamental research is needed to develop more durable and reliable connection concepts for these structures.*** Against this background, the current proposal describes pioneering research aimed at increasing the state-of-knowledge and developing improved design rules and performance characteristics for the following connection types: i) slip-resistant bolted connections in modular metal structures, ii) cables at the saddle supports in cable-supported structures, and iii) friction-stir welded (FSW) joints in lightweight aluminum bridge deck panels. In each project, graduate students will employ similar research tools, including: durability testing, finite element (FE) modelling, non-linear fracture mechanics, and risk and reliability analysis. This research will investigate complex phenomena, which experts are still struggling to fully understand and accurately model, including: corrosion, wear, fretting fatigue, and variable amplitude (VA) loading effects on fatigue behaviour. The planned experiments will validate analytical models, which will be used to investigate ways of improving connection performance through material selection, geometric design, and surface enhancement by various means.*** It is expected that this timely research will lead to an improved understanding of the broader fundamentals of connection behaviour and the proposal of new and innovative connection concepts, which will eventually be adopted in standards and change the way that we design new buildings and bridges. The high quality personnel (HQP) trained through this research will be highly sought after by the Canadian construction sector, where they will take on leadership roles, due to the specialized knowledge they will acquire in durability assessment, reliability analysis, and sustainable infrastructure design.