Durability Testing and Reliability Analysis of Connections in Lightweight Metal Structures

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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.