The seismic performance of multi-wythe masonry walls is known to be generally poor, as they can exhibit local failure modes by wythe separation and collapse of the external wythes. For retrofitting them, it is widely acceptable to install transverse ties in combination with other intervention methods to provide proper connections between the wythes. The value of using transverse ties in heritage multi-wythe masonry walls has been questioned in recent research. Different finite element models

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... e developed to simulate the behaviour of traditional transverse ties installed in multi-wythe walls. A simplified micro-model provided insight regarding stress transfer between the different elements of the system, and suggested that the traditional distribution of ties is inefficient. Macro-models were used to investigate the role of a single tie in resisting different loading conditions and found that the effect is minimal in most cases. The findings were in agreement with previous experimental research. An experimental program was performed to investigate non-traditional configurations and distributions of transverse ties. Large scale three-wythe walls were constructed and subjected to axial compression and lateral in-plane cyclic loads. Transverse ties made of FRP rebar were installed at different angles to the wall surface as opposed to the traditional leveled and perpendicular to the wall surface approach. Differences in the behaviour of the ties were observed including connection technique to the wall as well as the ability to transfer shear loads if placed in certain locations. Inclined transverse ties were grouped to form semi-continuous vertical, horizontal and diagonal elements to produce certain improvements in the structural performance of the wall in terms of lateral strength, stiffness degradation, energy dissipation, and post-peak behaviour.