The growing popularity of timber as a building material fuelled by a increasing rise of both environmental and social sustainability is pushing timber structures to new heights. Taller and more complex timber structures are leading to higher capacity connections being required to continuing ensuring safe, efficient, robust, and reliable timber structural designs. Connections play an important role in the overall safety and reliability of timber structures by introducing ductility into the structural system to counteract the inherent brittle material behaviour of wood. Steel-timber connections are a common practical connection choice for high capacity connection systems to maintain ductility requirements as structures increase in height. To allow for a higher capacities, these connections are increasing not only the size of the timber members being joined together but also increasing the size and number of fasteners. Both of these two effects increase the likelihood of brittle failure mechanisms to occur; however, the likelihood of brittle failure modes is still a complex function of both material and geometric properties. The aim of this master’s thesis is to develop a better understanding of when brittle failure mechanisms in high capacity timber connections occur to assist in the inclusion of explicit brittle failure models in reliable and robust timber connection design methods in tall timber structures. Simulation of material and geometric parameters of timber connections are presented to qualitatively assess the impact on capacity of the connection and the likelihood of brittle failure.