Modal analysis of historical masonry structures: linear perturbation and software benchmarking

The mechanical behavior of masonry materials has a common feature: a nonlinear behavior with high compressive strength and very low tensile strength. As a consequence, old masonry buildings generally present cracks due to permanent loads and/or accidental events. Therefore, the characterization of the global dynamic behavior of masonry structures should take into account the presence of existing cracks. This paper presents a numerical approach coupling linear perturbation and modal analysis in order to estimate the dynamic properties of masonry constructions, taking into account the existence of structural damage. First, the approach is validated on a masonry arch subjected to increasing loads, via three FE codes. Then, the same procedure is applied to a real masonry structure affected by a severe crack distribution.