Using the discrete element method to assess the seismic vulnerability of aggregated masonry buildings

The seismic vulnerability of masonry aggregates is assessed with an approach based on the discrete element method. In that purpose, a quasi-static push-over procedure has been developed, in which a load pattern, based on the building first mode of vibration, is applied to the studied structure. Using this approach, the magnitude of the horizontal load to be applied for the building to collapse is obtained after a short computation time, as well as a detailed description of the failure mechanism. These results can be useful, for instance, for identifying the weakness of a structure or for comparing quantitatively the vulnerability of different structures. The beneficial and negative effects on the seismic response of the aggregation are assessed by subjecting isolated and aggregated buildings to both in-plane and transverse loads. As observed by engineers during post-seismic field missions, the buildings at the extremities of the aggregate are more prone to damage, because, contrary to the buildings inside the aggregate, they are not efficiently braced by the neighboring structures.