Durability Testing and Reliability Analysis of Connections in Lightweight Metal Structures

在建筑物和桥梁等民用基础设施的设计中，美学和可持续性方面的考虑，如减少用户延迟成本和长期环境影响，越来越多地导致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质模块化解决方案可以实现显著的效益，这些解决方案可以延长使用寿命，提高预制程度，降低运输和安装成本，并显著缩短建造时间。这些材料也特别适合于“解构设计”这一新兴概念，这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，如何在结构使用寿命结束时更容易拆卸，以促进更高的再利用率。为了确保轻质金属结构在可持续性和社会效益方面发挥最大潜力，需要进行基础研究，为这些结构开发更耐用、更可靠的连接概念。* 在此背景下，当前提案描述了开拓性研究，旨在增加以下连接类型的知识水平并开发改进的设计规则和性能特征：i）模块化金属结构中的防滑螺栓连接，ii）缆索支撑结构中鞍形支座处的缆索，以及iii）轻质铝桥面板中的搅拌摩擦焊（FSW）接头。在每个项目中，研究生将采用类似的研究工具，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，专家们仍在努力充分理解和准确建模，包括：腐蚀，磨损，微动疲劳和变幅（VA）加载对疲劳行为的影响。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、几何设计和各种方式的表面增强来改善连接性能的方法。 预计这一及时的研究将有助于更好地理解连接行为的更广泛的基本原理，并提出新的创新连接概念，这些概念最终将被纳入标准，并改变我们设计新建筑和桥梁的方式。通过这项研究培训的高素质人员（HQP）将受到加拿大建筑部门的高度追捧，他们将在那里发挥领导作用，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.