EXAMPLE OF THE BENEFITS OF A DISSIPATIVE ROOF DIAPHRAGM IN THE SEISMIC RESPONSE OF MASONRY BUILDINGS

The paper discusses the role of a ductile dissipative roof-diaphragm in the re- sponse of masonry structures subjected to out-of plane rocking of peripheral masonry walls. The benefits of this design choice are highlighted referring to a case study building repre- sentative of a recurrent typology of single nave masonry church, characterized by transverse diaphragm-arches. The activation of a controlled rocking of the nave lateral walls, allowed by the non-linear response of the roof diaphragm, is shown to be a resource in order to re- duce the in-plane shear action on the façade and triumphal arch head walls. A criterion to proportion the roof strength is suggested in order to limit the walls rocking amplitude within acceptable values to satisfy the required damage limit state. The results, here presented refer- ring to a case study application, are part of a research work dealing with the role of the rock- ing mechanism in the safety of masonry buildings against earthquake actions.