Analysis of local shear effects in brick masonry infilled RC frames

Masonry infills panels placed among framed structures meshes have a relevant influence in presence seismic actions in terms of strength stiffness and global displacement capacity. In the case of RC structures, the modifications of internal forces due to infill-frame interaction may be not compatible with surrounding frame members strength especially considering additional shear forces arising at the ends of beams and columns in contact with the panel under lateral actions. Such effects may be in many cases the cause of unexpected brittle collapse mechanisms which compromise the safety of the entire structure. In this paper by means of a double (micromodeling and macromodeling) procedure regarding RC meshes infilled with hollow brick masonry, a parametric study is provided defining a connection between local shear forces in critical frame regions and axial force on diagonal pin jointed strut. Proposed strategy allows to predict effective local shear forces using the simple macromodeling approach to reproduce the effect of masonry infills in models.