G. MAGENES and A. DELLA FONTANA University of Pavia

A method for the simplified non-linear seismic analysis (pushover) of unreinforced masonry buildings is presented and discussed. The method is based on an equivalent frame idealization of multistorey walls subjected to in-plane loading. The formulation of the model, which is conceptually simple and makes use of simple strength formulations for piers and spandrels, is briefly described. An elastic-perfectly plastic behaviour with limited plastic deformation is assumed for pier elements. Spandrel beams are formulated similarly to piers, except for shear failure, for which Two alternatives have been considered: elastic-plastic or elastic-brittle behaviour. Applications of the method to multi-storey walls are presented and compared with the results of a more sophisticated non-linear finite element model. The role of the post-elastic behaviour of spandrel beam elements on the global behaviour of walls is discussed.