Experimental analysis of masonry infilled frames using digital image correlation

A measurement technique (digital image correlation) is used for a critical evaluation of simplified models for infilled framed structures. It allows for the assessment of displacement and strain fields in the panel of interest. Several specimens, including infilled and partially infilled frames were subjected to cyclic lateral loads. It was found that two very different deformation mechanisms appear in the masonry panels namely, a first one during the hardening phase and another one, completely different, during the softening stage. For the former, strain concentration bands are observed. After the peak load, horizontal bands appear in the middle of the panels. The Polyakov assumption, i.e. that the panel can be replaced by struts in the analysis, is validated in the hardening stage. However, the orientation of the struts suggested in the literature was not found experimentally. The experimental results demonstrate that the inclination of the bands depends on the brick dimensions and arrangement. Further, the final failure mechanism corresponds to a sliding shear mode.