Influence of masonry infill modelling on the seismic response of reinforced concrete frames

In this study the influence of masonry infills modelling on the seismic response of reinforced concrete frames is investigated. First, various models are described and discussed, then an reinforced concrete frame, designed to be representative of an existing building in Italy, is analysed by means of numerical non linear static (push-over) analyses considering both the bare frame (as a reference model) and the infilled one. Different macro-models based on the equivalent strut approach are used with the aim of carrying out a comparison between them. The analyses are performed by means of the OpenSees software package. Beams and columns are modelled with elastic beam elements connected in series to zero-length nonlinear rotational springs located at members ends for representing plastic hinges. The infills are modelled with truss elements, to which a uniaxial material is assigned. The parameters which characterize the uniaxial material change with the infill model adopted. The results show that there is a noticeable difference of stiffness and strength estimated by means of different models.