Micro and Macro-modeling Techniques for the Simulation of the Masonry Infilled R/C Frames under Earthquake Type Loading

Three types of numerical simulation techniques for the masonry infills are adopted in the current paper, namely a micro-modeling technique, a macro-modeling technique and a simulation where the masonry infill and the joint interface between the surrounding frame and the infill is represented by a diagonal strut model. Initially, the hysteretic behavior of three R/C frames with masonry infills tested at the Laboratory of Strength of Materials and Structures of the University of Thessaloniki are examined when they are subjected to horizontal cyclic loads. Non-linear finite simulations are employed, that can describe the reduction of strength and initial stiffness. The inelastic behavior of the frame is simulated including the non-linear simulations of the masonry infill, the formation of plastic hinges for the R/C frame at pre-defined locations and the sliding or the separation of the masonry infill from the surrounding R/C frame. The second part of the present work examines the effectiveness of the micro-modeling technique and that of the diagonal strut model for the numerical simulation of masonry infills inside R/C frame specimens when different types of openings are considered. The results from three framed masonry infill specimens that were tested under horizontal cyclic loading at the University of Osijek have been also utilized for the validation of the micro-model technique and the diagonal strut model that is proposed. Differences and similarities between the adopted numerical modeling techniques are commented and discussed.