Influence of soil deposit heterogeneity on the dynamic behaviour of masonry towers

The paper deals with the direct soil-structure interaction numerical modelling of an ideal masonry tower resting on deformable heterogeneous soil deposits. The stratigraphic heterogeneity is modelled dividing each deposit into several layers to implement four different shear wave velocity profiles. The resulting deposits can be classified as class C according to the Italian seismic building code prescriptions. Complete three-dimensional finite element dynamic analyses are carried out assuming a visco-elastic behaviour for both the tower and the soil, with the aim to investigate the effects of the soil heterogeneity on the dynamic response of the structure in the elastic field. Practical relationships are derived from the results to predict the deviation of the tower dynamic behaviour from a fixed-base condition.