FINITE-DISCRETE ELEMENT MODELLING OF MULTIPLE SHAKE TABLE TESTS ON UNREINFORCED MASONRY PROTOTYPES

Laboratory testing on prototypes of historical structures up to severe damage systematically shows the appearance of relevant discontinuities, related to the manufacturing process of masonry buildings as an assemblage both at the material level (laying of strong units in weak mortar) and at the construction level (weak connection between walls and between vertical and horizontal elements). Accounting for the formation of such discontinuities is challenging but necessary to reasonably replicate large amplitude shaking table tests. This paper presents a number of numerical simulations performed by the authors in the last decade of several testing campaigns on unreinforced masonry elements (walls prone to disintegration, cross vaults, wall enclosures) and small building aggregates. The modelling strategy falls within the finite-discrete element method, accounting for the elastic deformation of masonry units, as well as cracking, complete separation and creation of new contacts at the interfaces. Furthermore, the accrued experience allows to guide some modelling choices related to unit size, unit shape and Young’s modulus. Finally, the advantages (avoiding the a priori selection of a collapse mechanism, investigating the role of the vertical component) and disadvantages (neglecting the masonry compressive strength) of the investigated approach are discussed.