Proceedings of the Canadian Society of Civil Engineering Annual Conference 2021
Mass timber has proven to be a sustainable alternative to steel and concrete and its use in construction has increased significantly in the last decade. With building codes relaxing height limitations, there is a need for novel connection solutions for the next generation of tall timber buildings. There is also a need to ensure that mass timber products are being used responsibly and sustainably, with deconstruction and reuse being identified as important factors in this pursuit. This paper presents and discusses a new hybrid shear connection for mass timber buildings that allows for easy construction, deconstruction, and reuse of the structural elements. The connection consists of a fully threaded steel rod embedded into a CLT panel and reinforced with a layer of epoxy-based grout. The structural performance of shear connections with varying rod diameter and steel strength-grade, grout thickness, and CLT grade is analyzed. An insight into the behaviour under quasi-static monotonic incremental loads is given based on a comprehensive experimental campaign, with a total of 84 push-out tests performed on squared CLT specimens. Experiments show that strong and stiff behaviour can be achieved and that the yield point is clearly identifiable, supporting optimum capacity design strategies. This allows for the connection to be protected from damage and therefore reusable. Observed failure modes suggest that load-carrying capacity and stiffness models, as per common wood bolted connections, can be developed. This high-performance shear connection has great potential for deconstruction and reuse and supports prefabricated hybrid CLT-based structural solutions for large-scale building construction.