Formulazione di un modello meccanico per l’analisi di vulnerabilità sismica del costruito in muratura

Among the different approaches proposed in the literature for the vulnerability assessment, mechanical models seem particularly attractive. In fact, on the basis of few (easily traceable) mechanical and geometrical parameters, they allow to describe the seismic response of a structure, usually in terms of capacity curve. Focusing the attention on masonry buildings, these models are usually based on simplified hypotheses of the structural response. In particular in the most of the cases, they assume: the vertical compressive stress state on masonry resistant walls as uniform; floors as infinitely stiff; masonry piers as fully coupled. However, these hypotheses may result not equally suitable in case of a systematic application on masonry existing buildings. In fact, in many cases, floors are flexible (wooden floors or vaults) and the presence of “weak” spandrels (e.g. if tie rods or r.c. beam coupled lack) reduces the coupling of masonry piers. Thus, they may led to results which are on unsafe side. In the paper, a review of the model described in Cattari et al. (2004) is proposed by introducing some corrective factors aimed to consider these distinctive features. The comparison with the results from non linear numerical analyses shows the suitability of the proposed model.