Modeling strategies for non-linear seismic analyses: Comparison among EFM and FEM results on an existing URM case study

Italian building heritage is widely composed of masonry buildings, whose characteristics largely vary depending on geographical location, construction techniques and materials typology. This type of structures has shown a high vulnerability to horizontal loads that must not be ignored, especially due to the high seismic hazard of Italian territory. Hence, appropriate numerical models are required to assess the complex structural behavior of unreinforced masonry (URM) existing structures, implementing the non-linear behavior of both materials and structure. In this framework, two different approaches have been widely acknowledged: the Equivalent Frame Model (EFM) and the continuum Finite Element Model (FEM). This paper presents the application and comparison of these modeling strategies to an URM building dating back to XVII century, located in the Italian Alpine region (Roana, Vicenza). Non-linear static analyses were carried out by means of the software 3Muri (EFM), DIANA FEA and Midas FEA-NX (FEM). Results were compared in terms of ultimate resistance, capacity, ductility, and evolution of the damage state. Finally, assessment of the global behavior was carried out according to the Italian seismic code, pointing out the differences of the two approaches. Results showed that the EFM appears to be more conservative than FEM.