Evaluation of the seismic performance of brick masonry walls

Estimating the performance of structural elements requires the assessment of the response of those elements in terms of their response values (i.e. strengths, stresses, drifts, cracks, etc.) against loads and external forces of various kinds. For the seismic performance of masonry structures, until recently this approach was addressed in rather general terms with designers more interested in the survival of the structure in a maximum expected earthquake, with an acceptably low probability of occurrence. This traditional approach to seismic design is being replaced by performance-based design with the required performance depending on the level of the design seismic forces. This paper provides an overview of some of the methods for the evaluation of the in-plane resistance of masonry walls, which are already incorporated in national codes. Some results of recent experimental investigations of the shear capacity of in-plane loaded masonry walls subjected to cyclic loading are also presented with the aim of studying the potential for the application of these new concepts of assessment of seismic performance. The performance of unreinforced masonry walls in relation to the different design performance objectives and performance levels is then discussed