Testing and design protocol of dissipative devices for out-of-plane damage

During the past few decades, various technical solutions have been developed to improve the seismic performance of structural connections, as these determine the global response of buildings as much as single structural elements. However, in the case of heritage buildings, standard strengthening systems might have collateral effects owing to their high stiffness in comparison with historic substrata. Furthermore, little technical guidance is given to designers for dimensioning the retrofit of connections. Drawing on these observations, the authors have developed, in collaboration with Cintec Ltd, two dissipative devices. These are able to restore the connection between perpendicular masonry walls and to control relative displacements, thus reducing the load stress resultants transmitted to the substratum and the risk of pull-out or punching failures. The paper gives an overview of the experimental work conducted to identify performance parameters and exemplifies how these can be used for designing the strengthening, while satisfying code performance requirements.