Reinforced concrete (RC) structures with masonry infill walls constitute a significant portion of buildings, since their use is common in many countries due to the good performances of infills with respect to temperature, noise, moisture, fire and durability. Therefore, RC structures with masonry infill walls are popular form of construction in seismic regions too. Although, infill walls are mostly considered as non-structural elements and thus are typically neglected in the design process, the observations after earthquakes have shown that they interact with the structural system during seismic actions and that the traditional infill walls, connected with the mortar to the surrounding frame, are vulnerable to earthquake motions. Beside economic loss due to the repair or reconstruction of some infills, repair of damages to structural system, equipment, rental and relocation costs and general income losses, sometimes the consequences were total collapses of buildings and loss of human lives. Therefore, a huge effort has been made to consider the interaction of the structural system with the infill walls, but due to the complexity of the infill wall behaviour, no practical design procedures or solutions have been developed.
This research topic deals with the both experimental and numerical investigation of the behaviour of masonry infills. The research has two directions that overlap. The first is detailed investigation and understanding of all the factors influencing the behaviour of infills and the second one is developing the measures for the improvement of their behaviour. In order to achieve this, experimental testing of the system components as well as the infilled RC frames is performed. The testing is performed for in-plane loading and out-of-plane loading, as well as for combination of these two loading directions. Based on this experiments detailed numerical models for the analysis of infills are developed.
In the next period, additional experimental tests are planned to investigate different loading combinations and boundary conditions, as well as different geometric characteristics of the infill walls and RC frame. Parallel with that, comprehensive parametric studies are performed in order to derive the best solution that is optimized for the practical use in everyday design and construction practice.