Karantoni, Fillitsa1 and Pantazopoulou, Stavroula2
1 Assistant Professor, Department of Civil Engineering, University of Patras, Greece, firstname.lastname@example.org
2 Professor, Department of Civil Engineering, York University, Toronto, ON, Canada, email@example.com
The paper reviews two performance-based frameworks that may be used as the basis for the development of a seismic assessment code for load-bearing unreinforced masonry (URM) structures; these are the recently drafted EN 1998-3 (2020) provisions  and the Hellenic draft code for seismic assessment of load-bearing URM structures . Important URM characteristics that set them apart from common engineered construction are: the frequent absence of diaphragm action, the excessive distributed mass in the massive load-bearing walls, and the inherent brittleness and negligible tensile strength of URM. For seismic evaluation of URM structures, both guidelines define performance limits for assessment of the individual elements, and acceptance criteria based on deformation demand and supply measures at selected levels of performance. But the required methods of analysis and allowable simplifications and confidence limits differ between the two frameworks thereby influencing the demand and the calculation of member capacities. Mechanistic models that form the background to the basic acceptance criteria associated with reference performance limits are considered, but implementation differs in the two approaches, resulting from the idealizations allowed during modelling. The paper summarizes the two draft provisions with regards to member idealization and performance in an effort to understand and evaluate these differences, using as background the available evidence regarding deformation limits of masonry walls under in plane and out of plane actions.