A new discrete element model for the evaluation of the seismic behaviour of Unreinforced Masonry Buildings

The evaluation of the nonlinear seismic response of masonry buildings represents a subject of considerable importance whose resolution is nowadays a main research topic in earthquake engineering. Refined nonlinear finite element models require a huge computational cost that makes these methods unsuitable for practical application. In this paper an innovative discrete-element model, conceived for the simulation of the in-plane behaviour of masonry buildings, is presented. The basic idea of the proposed approach is to approximate the in-plane nonlinear response of masonry walls by an equivalent discrete element. This element is able to reproduce the typical in-plane collapse behaviour of a masonry wall subjected to earthquake loading. The reliability of the proposed approach has been evaluated by means of nonlinear incremental static analyses performed on masonry structures, for which theoretical and/or experimental results are available in the literature. The proposed computational strategy provides a relatively simple and practical tool which could be of significant value for the design and the vulnerability assessment of unreinforced masonry structures in seismic areas.