Numerical modelling of reinforced concrete frames with masonry infills and rubber joints

Masonry infill walls are critical components of reinforced concrete (RC) frames, which may be damaged even under earthquake events of moderate intensity, thus resulting in significant losses. Recent experimental and numerical studies have investigated innovative solutions for protecting these walls by reducing their interaction with the RC frame. Among these, specially shaped rubber joints were developed that can be inserted between the brick units, and between the masonry wall and the frame. In the present study, a novel computational modelling strategy is developed using ABAQUS to investigate the in-plane behaviour of RC frames with infill walls and rubber joints. The proposed approach employs threedimensional solid finite elements to simulate the concrete components, 3D beam elements for the reinforcing bars, and a mesoscale approach for the infill wall with rubber joint. The numerical strategy is validated against two past experimental studies whose results can be found in the literature, one on RC frames with traditional infill walls, the other on RC frames with traditional walls and walls with rubber joints. The results shed light on the effectiveness of the rubber in minimising the in-plane seismic damage to the bricks, by localizing the deformation mostly in the rubber joints, and reducing the overall stiffness of the infilled system. Further analyses are carried out to investigate the effect of the rubber joints' layout and stiffness on the behaviour and capacity of the system and its components.