Sensitivity analysis of seismic behaviour of masonry aggregates

Masonry buildings in aggregate are the most widespread structural typology in the Italian city centers and they are characterized by a wide structural variety; indeed, they may differ in geometry, materials, construction techniques and state of preservation. Seismic response of buildings in aggregate is influenced by the presence of adjacent ones, since they frequently share the same boundary walls. Therefore, the reciprocal interactions should be taken into account, in order to consider the “aggregate effect”. However, the ordinary lack of information about the entire aggregate makes their analysis more difficult than the case of isolated buildings. Even if several studies have been conducted, the main problems still concern the assessment of the reciprocal interactions between different parts of the same aggregate and the choice of the optimal portion of the aggregate for a unitary modelling. Hence, the aim of this paper is to better understand the “aggregate effect” by assessing the influence of the floors stiffness on the seismic global behavior of ideal case studies, based on the typical masonry aggregates in the North area of Florence. For this purpose, the results of a sensitivity analysis, performed through linear and nonlinear analyses by considering different boundary configurations, are presented.