Pushover analysis of reinforced concrete framed structures: comparison between response obtained using beam or multi-layered shell elements

In the context of the seismic vulnerability assessment of existing reinforced concrete buildings, the load-carrying capacity of structures is strongly affected by steel and concrete mechanical properties and construction details. In this work, the institute “A. De Gasperi – R. Battaglia”, located in Norcia, is chosen as case study. Two different modelling strategies have been adopted by using beam elements or multi-layered shell elements for the structural schematization. The non-linear behavior and the ductile or brittle failure mode of shell elements are evaluated using PARC_CL 2.0 crack model, implemented as user subroutine in Abaqus Code. The non-linear ductile behavior of beam elements is evaluated using, at each integration point, the moment/curvature and the axial force/strain relationships which are uncoupled. Brittle failure mode in columns, beams and beam-to-column joints are calculated using post-processing procedures based on analytical formulations provided by Italian NCT 2018 and Eurocode 8 Standard Code. The main scope of this paper is thus the evaluation of the structural response of the case study by using nonlinear finite element analyses, highlighting the benefits of using beam or shell element modeling