Numerical modelling of column failure due to the local shear interaction in infilled RC frames

The presence of masonry infills in Reinforced Concrete (RC) frames leads to the increase in their lateral strength and stiffness. Nevertheless, post-earthquake observed damage showed that infills can also cause potential brittle failures due to the local interaction with structural elements, thus producing a limitation of deformation capacity of the surrounding frame. A proper numerical model both for infills and RC members is necessary to reliably detect the shear failure of columns due to the local interaction with the masonry infill. Several researches dealt with this topic, by using the equivalent strut model or more complex models like the double- and triple-strut models or FEMapproaches. Nevertheless, the choice of the proper modelling strategies and degrading shear strength model is still a frontier issue for the most recent research works. This paper presents a preliminary numerical investigation on column shear failure due to the local interaction with masonry infills, starting from the results of some experimental tests on infilled frames presented in the literature, which exhibited this kind of failure. Different shear strength models and different strategies of macro-modeling for infills are applied to numerically reproduce the column shear failure and the global response. The modeling strategies are lastly compared with the experimental results to provide a support towards the choice of the most reliable numerical approach.