Review on the static, low-cycle and high-cycle fatigue behaviour of shear connectors in sustainable steel-concrete composite structures: experimental studies

This paper reviews the static, low-cycle, and high-cycle fatigue behaviour of demountable shear connectors in sustainable steel-concrete composite structures. Steel-concrete composite structures have gained popularity due to their high strength and stiffness, making them ideal for high-rise buildings and bridges. However, conventional non-demountable shear connectors, particularly welded-headed studs, pose challenges in terms of sustainability and recyclability. This paper explores the evolution of shear connectors by introducing the available types, categorising them into non-demountable and demountable types, and assessing their performance under static and varying fatigue loading conditions. Non-demountable shear connectors are first presented as the benchmark to facilitate the comparison. Through detailed evaluations of experimental analyses, the study highlights the ductility, stiffness, and load-bearing capacity under static loading, as well as fatigue resistance of demountable connectors, with a particular focus on the low-cycle fatigue regime. Additionally, the failure modes of a wide variety of demountable shear connectors are assessed. Emerging trends and potential directions for future research are also discussed, including design optimisation of demountable shear connectors, their adoption in prefabrication and modular construction systems, and the mechanical behaviour and durability assessment of shear connectors with or without AI-assisted algorithms.